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SKULL BASE 360°
Below presentation is
SKULL BASE 360°-Part 1
For
SKULL BASE 360°-Part 2
Please click or copy/paste in URL ...
Great teachers – All this is their work .
I am just the reader of their books .
Prof. Paolo castelnuovo
Prof. Aldo Stamm P...
For Other powerpoint presentatioins
of
“ Skull base 360° ”
I will update continuosly with date tag at the end as I am
gett...
Below presentation is
SKULL BASE 360°-Part 1
Indetail eloborate description for
each part of skullbase360 done at
www.skul...
Approach
1. External corridor doesn’t matter except cosmesis , only
internal corridor matters – so in Open approaches of skull
base...
Prof. Amin Kassam
CORRIDOR SURGERY
• Video 1
https://www.youtube.com/watch?v=J6ji53nKQy
0
Video 2
https://www.youtube.com/...
External carotid artery ligation – Note at division of common carotid , external
carotid artery is medial to internal caro...
Only to lesion lateral to meridian
of pupil in frontal sinus we have
to do osteoplastic flap
The landmarks for canine foss...
Enhanced T1-weighted magnetic resonance imaging (MRI),
coronal section demonstrates a right nasoethmoidal lesion (adenocar...
“Up & below” approach to frontal
sinus
Illustration of the septal incisions necessary to achieve good access to the entire
anterior wall of the maxillary sinus f...
(A) The microdebrider blade has been passed through an inferior meatal antrostomy. Note the anterior fulcrum (nasal
vestib...
The red arrows demonstrate
the endonasal approach, and the green arrows represents the transmaxillary
approach. The blue r...
Note that in the transmaxillary approach the
structures in the lateral wall of the sphenoid sinus are seen in a
more
perpe...
Close-up view of the cavernous sinus through the
transmaxillary
approach. Gasser.: gasserian.
The pink and orange lines
demonstrate the possible angles of maneuver in transmaxillary
approach.
In green is emphasized t...
General view of the radial endoscopic accesses to the skull
base --- The green arrows represent the endonasal approaches,
...
Modified denkers approach - Blue dotted line shows
the medial maxillary wall. (B) Panoramic view after removing the medial...
Schematic demonstrating how the removal of the lateral
aspect of the piriform overture (in the red circle) enables a wider...
Use combination of approaches when ever it is necessary -
Combined Transmastoid Middle Cranial
Fossa Approach
Rt lower cranial nerve shwannoma, which approach will be
better ,which approach will be better considering this side is
do...
Answer
• Amit Keshri says - eight nerve was normal,so was 7th,removed tumor
completely with retrolab approach and to get s...
Posterior wall of maxillary sinus
Periosteum after removal of
posterior bony wall of maxillary
sinus – this periosteum mus...
MPP/VN
LPP/V2
Anteriorly MPP & LPP are fused & posterioly only they are divided .
Anteriorly MPP & LPP are fused & posterioly only they are divided .
Erosion of right greater wing of
sphenoid in a case of maxillary
carcinoma
Medial pterygoid is in line with lateral wall of Sphenoid
-- The superior vertical limb represents the paraclival ascendin...
Lateral part of Posterior choanae is MPP
ET is just posterior to MPP
Lateral part of Posterior choanae is MPP
Medial pterygoid is in line with
Paraclival carotid
Tracking of infraorbital nerve leads to V2 & tracking of V2 leads to Trigeminal ganglion/ Middle
cranial fossa [ one of th...
Zygomatic nerve [ ZN ]
Infraorbital groove near inferior orbital fissure – If we drill supero-lateral to
infraorbital nerve it is nothing but Inf...
Infraorbital groove near inferior orbital fissure – If we drill
supero-lateral to infraorbital nerve it is nothing but Inf...
Red ring = V2
Inferior orbital foramen continues as pterygomaxillary fissure .
One line along Vidian nerve & another
line along V2
Lateral to LPP & infra-orbital nerve [ or
V2 ] is Infratemporal fossa
One transverse line from Vidian nerve connecting
vertical line of V 2 & another transverse line from V2
The space above transverse line of Vidian nerve is Pterygoid Recess of
sphenoid – Read the CT – scan/ Plane the surgery by...
The space above transverse line of V2 is
Middle cranial fossa ( Meckel’s cave ) –
Read the CT – scan/ Plane the surgery by...
Pterygo-palatine fossa
Pterygopalatine fossa. A, V2 (blue dotted line) coming out
from the foramen rotundum; B, green-yellow dotted line shows th...
EC – Ethmoidal crest – left nose
PVC , VC & FR are in 45 degree angle
line
Endoscopic view of PPG
Tracking of infraorbital nerve leads to V2 & tracking of V2 leads to Trigeminal ganglion/ Middle
cranial fossa [ one of th...
Zygomatic nerve [ ZN ]
Endoscopic view of foramen rotundum
area
Infratemporal fossa
Lateral pterygoid muscle devides
internal maxillary artery into 3 parts
1. The maxillary artery & Buccal nerve enters the infratemporal fossa between the
superior and inferior head of the
latera...
.
Anteriorly lingual nerve & posteriorly Inferior Alveolar
nerve coming lateral to medial pterygoid muscle
Forceps behind IAN Forceps behind LN
IAN = Inferior alveolar nerve
Triangle formed by temporalis muscle ,
MPM & LPM
Mandibulotomy approach Endospic view
Post-maxillectomy “Fat pad” over temporalis muscle – which
is seen as Fat Pad [ FP ] in the triangle formed by temporalis
...
Internal carotid artery going medial & posterior to
medial pterygoid muscle into Parapharyngeal space &
becoming Paraphary...
Internal carotid artery going medial & posterior
to medial pterygoid muscle into Parapharyngeal
space & becoming Paraphary...
After removing the LPM you will see Tensor veli palatini muscle (TVPM) coming
vertically downwards from anterior surface o...
After removing the LPM you will see Tensor veli palatini muscle (TVPM) coming
vertically downwards from anterior surface o...
Hand model --
left hand = medial & lateral pterygoid
right hand = index is parapharyngeal
carotid , middle is IJV , ring i...
Parapharyngeal space
Internal carotid artery going medial & posterior to
medial pterygoid muscle into Parapharyngeal space &
becoming Paraphary...
Post-styloid compartment = carotid space
Sphenoid osteum
Sphenoid osteum present at the juction of upper 2/3rd
& lower 1/3rd junction of Superior turbinate – this
became very usef...
Three sequential indentations are made with the blunt end of the 4-mm
microdebrider blade starting at the medial upper lim...
L-OCR & M-OCR
L-OCR – Triangle
1. Upper boarder – Optic nerve & Opthalmic artery
2. Posterior boarder – Clinoidal carotid
3. Lower board...
The optic strut has two neural-
facing surfaces( yellow dotted
lines) and one vascular-facing
surface (red dotted line).
[...
The bone of the anterior clinoid (AC) process
has been left in place, positioned within the
lateral opticocarotid recess.
...
classification of the ophthalmic artery types
http://www.springerimages.com/Images/MedicineAndPublicHealth/1-
10.1007_s101...
In both type a = intradural type,
b = extradural supra-optic strut types Opthalmic
foramen is in Optic canal
In Type c = extradural trans-optic strut type , the Opthalmic
foramen in Optic strut
L-ocr is the space in Optic strut - not the space
in Anterior clinoid process
Note Optic strut
Note Optic strut
- Right Op...
Pneumatization of anterior clinoid process – in various planes + onodi cell on
both sides of sphenoid [ when transverse se...
The same cadaver photo what you are seeing in CT scan above – Note the supraoptic
pneumatisation [ present in anterior cli...
ICAcl clinoidal portion of the internal carotid artery , The clinoidal
segment of the internal carotid artery faces the po...
Red ring – Pneumatization in Optic
strut – which is nothing but L-OCR
M-OCR
Sagittal sections and superior views of the sellar region showing the optic nerve and
chiasm, and carotid artery. The pref...
1. M-OCR is nothing but Middle Clinoid Process [ indicated by
Green Button in both photos ]
2. M-OCR is the junction point...
The mOCR is located just medial tothe paraclinoidal-supraclinoidal ICA transition and inferior to
the distal cisternal seg...
1. The mOCR is placed at the confluence of the sella, tuberculum sellae, carotid
protuberance, optic canal and planum sphe...
Limits of the bone resection – Inner ring in below photo
• Posterior ethmoidal arteries
• Medial OCRs
SIS & IIS
Pituitary present between “ four blues”
SIS – superior intercavernous sinus &
IIS – inferior intercavernous sinus
1. Note ASIS & PSIS
2. Note Subarachnoid space at antero-superior area , which is the potential
CSF leak area in pituitary...
PSIS – Posterior superior intercavernous sinus
ASIS & PSIS together called CIRCULAR SINUS
Cavernous Sinus
Right cavernous sinus dissection. The quadrilateral delimits the right cavernous sinus area.
a Before periosteal layer rem...
Clivus
1. Upper Clivus
2. Middle Clivus
3. Lower Clivus
Basi occiput & basi sphenoid
Groove for medulla on Lower Clivus [ =
Basi Occiput ]
The 6 linear landmarks of the PCF superimposed on a midsagittal T1-weighted MR
imaging from a patient with CMI: herniation...
1. Upper clivus – Upto 6th nerve entry dorello’s canal (petro-clival junction)
2. Middle clivus – from 6th nerve to jugula...
Pneumatization of the sphenoid sinus
The middle third (M. 1/3rd) begins at the sella
floor (SF) and extends to the floor of the sphenoid sinus (SSF), and the l...
Pregnant of upper clivus is Sella
Infrapetrous Approach
Carotid-Clival window – Mid clivus
a. Petrosal face
b.Clival face
See the lower clivus relation to the
cochlea
In conchal sphenoid surgical landmarks –
1. posterior end of vomer or
keel of sphenoid tells about
the position of pituita...
See the relationship between lower boarder of posterior end of vomer &
clivus – vomer lower boarder is at junction of mid ...
http://www.neurosurgicalapproaches.
com/2013/08/25/
Anterior cranial fossa dura Posterior cranial fossa dura
Very rare specimen..The vbj is far
inferior to floor of sphenoid sinus
The foramen lacerum (FL) is located lateral to the floor of the sphenoid sinus
at the level of the
spheno-petro-clival con...
Infrapetrous Approach
Carotid-Clival window – Mid clivus
a. Petrosal face
b.Clival face
When we are drilling lower clivus – lateral to
hypoglossal canal we get Jugular fossa
Inferior clival line (Fernandez-Miranda et al. 2012 )
The longus capitis and rectus capitis anterior muscle attach on the ...
Transcochlear approach
Note CL [ Lower clivus ] in these
photos after drilling of cochlea
Note CL [Lower clivus ] in these photos after drilling of cochlea
The clivus bone (CL) can be seen
medial to the internal ...
Note CL [Lower clivus ] in these photos
after drilling of cochlea
BT- basal turn of the cochlea Fig. 8.34 The bone medial ...
Note CL [Lower clivus ] in these photos
after drilling of cochlea
Note cochlear aqueduct [ CA ]
Here ICA is vertical part ...
Note CL [ clivus ] in these photos after
drilling of cochlea
Note CL [Lower clivus ] in these photos
after drilling of cochlea
Note the contralateral vertebral
artery [ CVA ] in below...
Lower clivus in Infratemporal fossa
approach
PVC – is occupied by Ascending
palatine artery (APA)
Craniopharyngioma removal -
Lilliquest membrane & Basillar artery
V3 & MMA
V 3 falls like niagara falls from middle cranial fossa to infratemporal
fossa 90 degrees away from V1 & V2 – it is anterio...
ATN = Auriculotemporal nerve
MMA
IAN = Inferior alveolar nerve
My forceps touched the lingual nerve , posterior to this LN is Inferior
alveolar nerve – These two nerves present in trian...
Chorda[CT] attached to LN
Chorda[CT] attached to LN
Schematic diagram for infratemporal
fossa approach
Sometimes V3 can be seen in the sphenoid sinus
– in “pneumosinus dilatans multiplex”
The greater wing of sphenoidal is almost completely pnematised.
So is the temporal bone on the left.the Left carotid can b...
V3 & MMA
V3 & MMA
V3[MN] & MMA & ET in lateral & Anterior skull base – see the
relationship of ET tube which is medial to V3 & MMA
Posterior boarder of Lateral pterygoid bone
leads to Foramen Ovale [ FO ] – Dr.Kuriakose
Posterior boarder of Lateral Pterygoid bone leads to Foramen
Ovale [ FO ] – Dr.Kuriakose
Endoscopically [ Anterior skull base ] if we follow upper end of LPT posteriorly we can
reach V3 [ Posterior boarder of La...
In Infratemporal fossa approach- Posterior boarder of Lateral
pterygoid bone leads to Foramen Ovale [ FO ] – Dr.Kuriakose
V3 is anterior (infront) to Horizontal carotid (=
Petrous carotid ) & ET – It cause indentation on the
ET also .
In open approaches in maxillary swing approach as long
as you stay lateral to ET you will not injure the
horizontal part o...
Petrous carotid & paraclival carotid is
SADDLE shape – LEG of the rider is V3
V 3 is anteriror to all the 3 structures - Petrous carotid
& ET & Parapharyngeal carotid [ very imp ]
Cochlea in anterior skull base
b is cochlea in middle cranial
fossa – cochlear angle between
GSPN & IAC
V3 is an important landmark
to locate the post-styloid compartment, as it is anterior
to this space (Falcon et al. 2011 ) .
TP & LP
See the relationship of MPP & TP
which is just posterior
Sinus of Morgagni - In nasopharyngeal carcinoma, the tumor may
extend laterally and involve this sinus involving the Mandi...
See the relationship between
LPP & V3 which is just posterior
Eustachian tube
ET is just posterior to MPP [ Lateral part of Posterior choanae is MPP ]
ET is just posterior to MPP
ET is pointing like an ARROW the posterior genu
of internal carotid [ ICAp & CF is parapharyngeal
carotid ]
Sinus of Morgagni - In nasopharyngeal carcinoma, the tumor may
extend laterally and involve this sinus involving the Mandi...
black asterisks medial corridor to ICAp – TVPM attached to
anterior surface of ET – so if we go inbetween MPM & TVPM
we re...
Bony-cartilagenous junction of ET tube is at posterior
genu of carotid - ET is pointing like an ARROW the
posterior genu o...
Yellow arrow - Bony-cartilagenous junction of ET tube is
at posterior genu of carotid - ET is pointing like an
ARROW the p...
V 3 is anteriror to all the 3 structures - Petrous carotid
& ET & Parapharyngeal carotid [ very imp ]
ET tube in SPF [Spheno-petrosal fissure]
At bony-cartilagenous junction of ET tube – Horizonal
carotid & Parapharyngeal carotid is above & below ET -
My understand...
In open approaches in maxillary swing approach as long
as you stay lateral to ET you will not injure the
horizontal part o...
Fossa of Rossenmuller apex is laceral carotid [ Foramen Lacerum ]
pharyngeal recess (fossa of Rosenmüller), which projects...
endonasal approaches to expose the
area between the ICAs belong to the sagittal plane, and the
approaches
around the ICA d...
Note that the eustachian tube indicates the carotid canal only approximately. In other words, it lies on
a different CORON...
Note that the eustachian tube indicates the carotid canal only approximately. In other
words, it lies on
a different CORON...
Surgeons should have in mind that the external orifi ce of the carotid canal is not on
the same
coronal plane of the foram...
SOF [ Superior Orbital Fissure ]
Parts of SOF
1. Lateral part- LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal
N.,Trochlear N.
2.Middle par...
Parts of SOF
1. Lateral part- LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal
N.,Trochlear N.
2.Middle par...
Accessing intraconal lesions endonasally requires manipulation of the extraocular
muscles. The nerve branches that supply ...
SOF is the space between two Structs – Superiorly OS [
Optic Strut ] & Inferiorly MS [ Maxillary Strut ]
SOF is the space between two Structs – Superiorly OS [
Optic Strut ] & Inferiorly MS [ Maxillary Strut ]
SOF is the space between two Structs – Superiorly OS [
Optic Strut ] & Inferiorly MS [ Maxillary Strut ]
Anterior view of ...
Yellow line = “nasal” part of SOF
Clinically, the SOF and CS apex
represents a continuum.
endoscopic endonasal viewpoint the nasal window to
SOF is above V2, and below the lateral
optico-carotid recess.
blue-sky ...
Zonule of zinn - inserts on the infraoptic tubercle, which is often
found as a canal located beneath the optic strut .
The structure Infero-lateral to SOF is –
Horizontal part of carotid
Anterior to L-OCR is Superior Orbital
Fissure
SOF - Anterior
SOF - Posterior
MS- Maxillary strut /// Average
distance from the FR at PPF and the vertical segment of ICAc is
35 mm [ 3.5cm ] (Amin et a...
SOF , Middle Fossa , V3 in line
vertically
GSPN-VIDIAN NERVE
GSPN passes above Horizontal [=petrous] carotid & passes
underneath V3 & crosses petro-paraclival carotid junction at
fora...
The bone overlying the internal auditory canal has been removed
and the dura of the canal has been removed near the fundus...
Fig. 2.62 The course of the horizontal segment of the internal carotid
artery (ICAh), as seen from the middle cranial foss...
Fig. 5.47 The view after completion of the middle crannial fossa approach. AE Arcuate eminence,
BB Bill’s bar, C Cochlea, ...
In Infratemporal fossa - Note that the
greater petrosal nerve (GPN) is adherent
to the dura, and that retracting the dura
...
Foramen lacerum
AFL = Anterior foramen
lacerum
* [ black asterisk ] = foramen
lacerum
Petrolingual area = foramen
lacerum
After elevating V3 anterior[infront] to ET & petrous carotid
observe -- GSPN continues as VN [ VN is lateral to paraclival...
GSPN & GSPN groove in Surpra petrous window
ET eustachian tube, GPN greater petrosal nerve, MCFd dura of the middle crania...
Vidian nerve is formed by GSPN & Deep petrosal nerve – so GSPN (passes
underneath V3) crosses laterally the Horizontal car...
Trans-pterygoid approch-- Vidian Artery present in 60% & enters at the junction of Horizontal
carotid & paraclival carotid...
Vidian nerve - lateral to paraclival carotid &
medial to FO [ Foramen Ovale ]- actually it is
GSPN
Vidian canal & Spheno-palatine
foramen are in 90 degrees
Vidian nerve - lateral to paraclival
carotid
Vidian nerve - lateral to paraclival carotid
Vidian nerve - lateral to paraclival
carotid
Vidian nerve - lateral to paraclival carotid
Close vision of the middle cranial
fossa. The gasserian ganglion has been rem...
Vidian nerve - lateral to paraclival
carotid
Axial T2-weighted magnetic resonance imaging (MRI) sequence
at the level of the vidian canal: 1, clivus; 2, pterygoid; 3,
...
The space between V1 & V 2 and V2 & V3
is sphenoid sinus
Middle cranial fossa approach –
the nerve between V2 & V3 is VN
A...
Infratemporal fossa approach
type C
Middle cranial fossa approach –
the nerve between V2 & V3 is VN
Foramen lacerum
AFL = Anterior foramen
lacerum
* [ black asterisk ] = foramen
lacerum
Petrolingual area = foramen
lacerum
Vidian artery – origin from Laceral
segment
Lateral Recess is the space between V2
& Vidian nerve .
Courtesy – Dr. Satish Jain , Jaipur
Lateral Recess is the space between V2
& Vidian nerve .
Here TI [ trigeminal impression ] is V2
LRSS = Lateral recess of the
sphenoid sinus
Floor of Lateral recess is by ET ----
BS basisphenoid, ET eustachian tube, LRSS lateral recess of the sphenoid sinus, OPPB...
Surpra petrous window
ET eustachian tube, GPN greater petrosal nerve, MCFd dura of the middle cranial fossa, MMA
middle me...
Carotid nerve
Middle cranial fossa approach
The middle fossa retractor is fixed at the petrous
ridge (PR).
AE Arcuate eminence, GPN Greater petrosal
nerve, M Middle m...
Petrous apex bone
Petrous apex - Quadrangular area
Petrous apex – Triangular area
Triangles
http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-cavernous-sinus-
cadaver-study - Endoscopic view o...
6th nerve is parallel to V1 – in the same direction of V1
http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-
cavernous-sinus-cadaver-study- Endoscopic view of...
1.Supra Trochanteric & Infratrochanteric Triangles
2. Upper & lower dural rings
http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-cavernous-
sinus-cadaver-study -Endoscopic view of...
http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-
cavernous-sinus-cadaver-study - Endoscopic view (...
Triangles of Middle cranial fossa – see Ant. Medial & Ant. Lateral triangles in both photos.
http://www.eneurosurgery.com/...
Fig. 22.31 Clinoidal and oculomotor triangles
have been opened and the anterior clinoid removed
up to the optic strut, exp...
Opticocarotid traiangle by Pterional
approach
CAROTID
KISSING CAROTIDS
1. http://radiopaedia.org/articles/kissing-carotids
2. http://www.ncbi.nlm.nih.gov/pubmed/17607445
• The ...
Cervical kissing carotids – here also papaphayrngela kinking
present http://www.radrounds.com/photo/cervical-kissing-
caro...
An Aberrant Cervical Internal Carotid Artery in the Mouth
http://amjmed.org/an-aberrant-internal-carotid-artery-in-the-mou...
Intrasellar kissing carotid arteries -This anomaly is particularly
important since it may cause or mimic pituitary disease...
Looping / Kinking of
Parapharyngeal carotid
kinking or looping of the ICAp - when looping present para-pharyngeal carotid
comes to pre-styloid compartment – previousl...
The stylopharyngeus and styloglossus
muscles are critical landmarks, being usually placed anterior to the great
vessels (D...
Cervical kissing carotids – here also papaphayrngela kinking
present http://www.radrounds.com/photo/cervical-kissing-
caro...
An Aberrant Cervical Internal Carotid Artery in the Mouth
http://amjmed.org/an-aberrant-internal-carotid-artery-in-the-mou...
In this kinking of ICA also Prof.Mario
Sanna uses very flexible ICA stents
Relation of Eustachian tube & looping of
parapharyngeal carotid & styloid process
The external carotid artery passes deeply to the digastric and stylohyoid
muscles, but superficially to the stylopharyngeu...
Intratemporal carotid = Horizontal
carotid[= Petrous carotid] + Vertical
carotid
Endoscopic view of the eustachian tube orifice
(arrow).- Note Internal carotid artery
In Infra-temporal fossa approach
The full course of the intratemporal internal carotid artery has
been freed. AFL Anterior...
Pterygoid trigone – just anterior to foramen lacerum in
both photos is Pterygoid trigone
Note the Cochlea basal turn anterior
wall in left photo
Note that the basal turn of the cochlea (BT) starts to curve
superiorly near the internal carotid artery (ICA), a short di...
In most cases, the medial aspect of the horizontal
portion of the internal carotid
artery is not covered by bone, but simp...
GSPN bisects the Petrous carotid & V3 and
Vertical part of Facial nerve bisects Jugular bulb
In most cases, the medial aspect of the horizontal
portion of the internal carotid
artery is not covered by bone, but simp...
Post-operative vasospasm of laceral segment [ carotid
mobilization done for tumor removal ]
Paraclival carotid
TG ( Trigeminal ganglion ) is lateral to
Paraclival carotid
Infrapetrous Approach
Carotid-Clival window – Mid clivus
a. Petrosal face
b.Clival face
After drilling the carotid canal what we see is endosteal layer ,
not directly the ICA – Dr.Janakiram
Subperiosteal/Subadv...
Fig. 15.25 A case of left glomus jugulare tumor in our early experience.
Subadventitial dissection has been performed beca...
Meckels cave - Trigeminal notch at
petrous apex
Carotid nerve
Petrolingual ligament [ PLL ] &
Foramen Lacerum [ FL ]
Lingula of sphenoid
Lingula of sphenoid
Lingula of sphenoid
red asterisk = lingula of the
sphenoid
black arrowhead = lingula of the
sphenoid
PLL- Petrolingual ligament - considered as a
continuation of the periostium of the carotid canal
(Osawa et al. 2008 ) .
Infrapetrous Approach
Carotid-Clival window – Mid clivus
a. Petrosal face
b.Clival face
“Front door” to Meckel’s cave
PLL - It can be considered
the border between the horizontal and cavernous portions of the
i...
Nerves in lateral wall of cavernous in
JNA case
Foramen lacerum - The petrous ICA then curves upward above the
foramen lacerum (FL), thus giving the anterior genu. The se...
Vidian artery – origin from Laceral
segment
1. The foramen lacerum (FL) is located lateral to the floor of the sphenoid sinus at the
level of the spheno-petro-clival ...
PLL = INFERIOR SPHENOPETROSAL LIGAMENT
ACP anterior clinoid process, APCF anterior petroclinoid fold, DS dorsum sellae, IC...
Parasellar carotid
Parasellar carotid – shrimp shaped
It covers four segments of the ICA: (1) the hidden segment; (2) the inferior horizontal...
Retro, Infra, Presellar prominences
A) Cadaveric dissection image taken within the sphenoid sinus, with removal of bone over the lateral sphenoid wall.
The pa...
http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-
cavernous-sinus-cadaver-study- Endoscopic view of...
Branches of cavernous carotid
1. Meningohypophyseal trunk
2. Inferolateral trunk
The anterior lobe of the pituitary gland ...
Superior Hypophyseal Arteries
[ SHAs ]
The anterior lobe of the pituitary gland is mainly fed by the superior
hypophyseal arteries while the posterior lobe is fe...
Superior Hypophyseal Arteries [ SHAs ]
- more commonly arise from the paraclinoid ICA - In rare cases SHAs originate
from ...
Meningohypophyseal trunk
The MHT is traditionally described as having three branches:
1. the inferior hypophyseal artery, IHA
2. the dorsal meninge...
At superior part of Siphon carotid , SHA arises where as
inferior part of Siphon carotid MHT [ Inferior
hypophyseal artery...
DMA main feeder of dorellos
segement of 6th nerve
DMA main feeder of dorellos
segement of 6th nerve
Inferolateral trunk
Inferolateral trunk
In most cases ILT passes superiorly to the
abducens nerve (Inoue et al. 1990 ;
Jittapiromsak et al. 2010 ) .
In most cases ILT passes superiorly to the
abducens nerve (Inoue et al. 1990 ; Jittapiromsak et al. 2010 ) .
Cholesterol granuloma
cholesterol granuloma immediately
behind the ICA
ICA Clin.: clinoid, clinoidal
Dural rings – the ICA between upper
& lower dural ring is Clinoidal ICA
Cl clivus, ICAc cavernous portion of the internal carotid artery, ON optic nerve, PG pituitary
gland, PS planum sphenoidal...
Lower dural ring is nothing but COM [ Carotico-occulomotor membrane ] - The dura
lining the inferior aspect of the anterio...
lower dural ring - This ring is often incomplete on the medial side and often
a venous channel can follow the paraclinoida...
blue-sky arrow = upper dural ring,
The lower dural ring is given by the COM [ Carotid-oculomotor
membrane ] , that lines the inferior surface of the ACP. It ...
Upper & lower dural rings
1.Supra Trochanteric & Infratrochanteric Triangles
2. Upper & lower dural rings
ICAcl clinoidal portion of the
internal carotid artery , The
clinoidal segment of the internal
carotid artery faces the po...
ICA Clin.: clinoid, clinoidal [ Observe here also – posterior border of Optico-
carotid recess is Clinoidal ICA ]
ICA Clin.: clinoid, clinoidal
ICA Clin.: clinoid, clinoidal
ICA Clin.: clinoid, clinoidal
ICA Clin.: clinoid, clinoidal
Intracranial portion of ICA [ICA i]
The mOCR is located just medial to the paraclinoidal-supraclinoidal ICA
transition and inferior to the distal cisternal se...
Opthalmic artery – Retrograde branch of Intracranial carotid
Branches of the cavernous internal
carotid artery ( ICA ), a ...
In the lateral border of the chiasmatic cistern the first part of
the ICAi is visible.
Note Optic tract here which is abov...
Supra-clinoidal carotid=1st part of
intracranial carotid
APAs anterior perforating arteries, ICAi intracranial portion of
the internal carotid artery, OT optic tract, SF Sylvian f...
ACA anterior cerebral artery, APAs anterior perforating arteries, FOA fronto-orbital artery,
FOV fronto-orbital vein, FPA ...
ICA dividing into ACA and MCA
Optic tract [ OT ]
Pterional
CRANIOPHARYNGIOMAS-Removal corridors.
Cyst of craniopharyngioma
Surpra petrous approach
Surpra petrous window [ see the GSPN groove here ]
ET eustachian tube, GPN greater petrosal nerve, MCFd dura of the middle...
Infrapetrous approach
Inferior petrosal sinus is superior to jugular tubercle &
hypoglossal canal is inferior to jugular tubercle
Infratemporal ...
The pontomedullary junction.
1. The exit zones of the hypoglossal and abducent nerves are at
the same level [ same vertica...
In infrapetrous approach there are chances of injury to 6th nerve [ in dorello’s
canal medial to paraclival carotid ] & 12...
When we are drilling lower clivus – lateral to
hypoglossal canal we get Jugular fossa
Adenoid cycstic carcinoma clivus -- Just look at the carotid. .The paraclival both sides
360 degree encased..look at the m...
Sub frontal approach
Fig. 2.1 Drawing showing the skin incision (red line), the craniotomy
and the microsurgical intraoperative view of the sub...
Fig. 2.4 Intraoperative microsurgical photograph showing contralateral
extension of the tumor (T) dissected via a unilater...
Fig. 2.5 Drawing showing the skin incision (red line), the craniotomy
and the microsurgical anatomic view of the subfronta...
Supraorbital approach - Fig. 3.2 Illustrations comparing the incision and
bony exposure in a supraorbital craniotomy with ...
Frontotemporal approach
Fig. 4.6 a Craniotomy. b When the flap has been removed the
lesser wing of the sphenoid is drilled down to optimize the mo...
Fig. 4.8 Intradural exposure; right approach. Before (a) and after (b) opening of the
Sylvian fissure. A1 first segment of...
Fig. 4.9 Intradural exposure; right approach. a Instruments enlarging the optocarotid
area. b Displacing medially the post...
Fig. 4.10 Intradural exposure; right approach; enlarged view. A1 first segment of the anterior
cerebral artery, A2 second ...
Fig. 4.11 Intradural exposure; right approach; close-up view ofthe interpeduncular fossa. AchA
anterior choroidal artery, ...
Endoscope-assisted microsurgery [ 45° endoscope in a corridor
between the carotid artery and the oculomotor nerve ]-- Fig....
Fig. 4.12 Intradural exposure; right approach; microsurgical (a) and endoscopic (b–d) views.
AchA anterior choroidal arter...
Fig. 4.13 Intradural exposure; right approach; microsurgical (a)
and endoscopic omolateral (b) and contralateral (c) views...
Fig. 4.13 Intradural exposure; right approach; microsurgical (a)
and endoscopic omolateral (b) and contralateral (c) views...
Fronto-temporal orbitozygomatic
transcavernous approach
COM= Caratico-occulomotor
membrane , DR = dural ring
Division of PComA
Fig. 4.15 Microsurgical view; extradural anterior
clinoidectomy. a Exposure and drilling of the anterior clinoid process
a...
Fig. 4.16 Microsurgical view; intradural anterior clinoidectomy. a, b After the dura above the
anterior clinoid process ha...
Fig. 4.16 Microsurgical view; intradural anterior clinoidectomy. a, b After the dura above the
anterior clinoid process ha...
Posterior clinoidectomy
FTOZ – Fronto-temporal
orbitozygomatic approach
FTOZ – Fronto-temporal
orbitozygomatic approach
Subtemporal approach
Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura
obtained thro...
Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura
obtained thro...
Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura
obtained thro...
THE FULLY ENDOSCOPIC SUBTEMPORAL APPROACH [ from
Shahanian book ] - The traditional middle fossa subtemporal approach requ...
Q) a Occulomotor (III) nerve. b
Internal carotid artery (ICA). c
Posterior cerebral artery (PCA).
d Superior cerebellar ar...
Carotid artery bleeding
SKULL BASE 360°
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SKULL BASE 360°-Part 1
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Skull base 360°- part 1

  1. 1. SKULL BASE 360° Below presentation is SKULL BASE 360°-Part 1 For SKULL BASE 360°-Part 2 Please click or copy/paste in URL or weblink area http://www.slideshare.net/muralichandnallamoth u/skull-base-360-part-2-39401703 [ Dated: 26-10-14 ] I will update continuosly with date tag at the end as I am getting more & more information
  2. 2. Great teachers – All this is their work . I am just the reader of their books . Prof. Paolo castelnuovo Prof. Aldo Stamm Prof. Mario Sanna Prof. Magnan
  3. 3. For Other powerpoint presentatioins of “ Skull base 360° ” I will update continuosly with date tag at the end as I am getting more & more information click www.skullbase360.in - you have to login to slideshare.net with Facebook account for downloading.
  4. 4. Below presentation is SKULL BASE 360°-Part 1 Indetail eloborate description for each part of skullbase360 done at www.skullbase360.in » Presentation by » Dr. N. Murali Chand DLO MS (ENT) FHM » Fellowship in HIV medicine, MAMC, New Delhi » My website = www.integratedmedicine.co.in • www.skullbase360.in » Cell= +91 99496 77605
  5. 5. Approach
  6. 6. 1. External corridor doesn’t matter except cosmesis , only internal corridor matters – so in Open approaches of skull base also use endoscope to get best results – see this video how the Dr. Dugani Suresh ; Neurosurgeon is using endoscope in Weber Fergusson incision https://www.youtube.com/watch?v=Y95Jf3u8S8o&feature=y outu.be 2. Most of the times “Don’t cross the NERVES”
  7. 7. Prof. Amin Kassam CORRIDOR SURGERY • Video 1 https://www.youtube.com/watch?v=J6ji53nKQy 0 Video 2 https://www.youtube.com/watch?v=56Wt4vQ9 KgE
  8. 8. External carotid artery ligation – Note at division of common carotid , external carotid artery is medial to internal carotid artery – Sometimes the division may go up very high in neck .
  9. 9. Only to lesion lateral to meridian of pupil in frontal sinus we have to do osteoplastic flap The landmarks for canine fossa puncture/trephine are the intersection between a vertical line through the pupil and a horizontal line drawn through the floor of the nose.
  10. 10. Enhanced T1-weighted magnetic resonance imaging (MRI), coronal section demonstrates a right nasoethmoidal lesion (adenocarcinoma) with an “hourglass” intradural extension through the ethmoidal roof. Diffuse enhancement of the dural layer (arrowheads) over the orbital roof is suspicious for neoplastic spread. The vertical lines limit the area of the dura safely resectable by a pure endoscopic approach.
  11. 11. “Up & below” approach to frontal sinus
  12. 12. Illustration of the septal incisions necessary to achieve good access to the entire anterior wall of the maxillary sinus for tumors either originating from this region or with a significant anterior wall attachment. (B) Cadaveric image demonstrating the access to the anterior wall (AW) of the maxillary sinus with a 70-degree diamond drill (D).
  13. 13. (A) The microdebrider blade has been passed through an inferior meatal antrostomy. Note the anterior fulcrum (nasal vestibule, broken white arrow) and the posterior fulcrum (inferior meatal antrostomy, white arrow). The region of the maxillary sinus that can be cleared through this access is shaded. This shaded region is smaller with a middle meatal antrostomy. The single fulcrum of the canine fossa puncture is indicated (white arrow) (B,C,D), illustrating how the entire maxillary sinus can be accessed as the blade only has a single fulcrum.Medial , posterior & Lateral walls approached through Caldwel-luc
  14. 14. The red arrows demonstrate the endonasal approach, and the green arrows represents the transmaxillary approach. The blue rectangle shows the parasellar structures. A more perpendicular angle of attack is achieved in the transmaxillary approach, and the distance to the target from this route is equal to or smaller than that in the endonasal approach. Temp.: temporal.
  15. 15. Note that in the transmaxillary approach the structures in the lateral wall of the sphenoid sinus are seen in a more perpendicular way, facilitating dissection of this region.
  16. 16. Close-up view of the cavernous sinus through the transmaxillary approach. Gasser.: gasserian.
  17. 17. The pink and orange lines demonstrate the possible angles of maneuver in transmaxillary approach. In green is emphasized the possibilities of resection through transmaxillary approach.
  18. 18. General view of the radial endoscopic accesses to the skull base --- The green arrows represent the endonasal approaches, the red arrows represent the transmaxillary approaches, and the purple arrows represent the subtemporal approaches. Note the multiple possibilities of combination of these approaches.
  19. 19. Modified denkers approach - Blue dotted line shows the medial maxillary wall. (B) Panoramic view after removing the medial maxillary wall. Yellow dotted line shows the connected nasal cavity with maxillary sinus the maxillary sinus.
  20. 20. Schematic demonstrating how the removal of the lateral aspect of the piriform overture (in the red circle) enables a wider approach (the green cone compared with the yellow cone) to the lateral regions (pterygopalatine and infratemporal fossa).
  21. 21. Use combination of approaches when ever it is necessary - Combined Transmastoid Middle Cranial Fossa Approach
  22. 22. Rt lower cranial nerve shwannoma, which approach will be better ,which approach will be better considering this side is dominant sinus.
  23. 23. Answer • Amit Keshri says - eight nerve was normal,so was 7th,removed tumor completely with retrolab approach and to get space,the sigmoid plate was decompressed and sinus retracted posteriorly after RMSO [ Retro mastoid sub-occipital ] craniotomy without opening dura posteriorioly. • Murali Chand Nallamothu For lower cranial nerve schawnnoma POTS approach is the best - but here you are saying it is dominent sinus , no need to sacrifice sigmoid sinus -- so in this case we can use extended translabyrinthine approach for the AFB area part & at carotid canal area part of the tumor can be removed by externally which is included in the lower C - shaped incision • Murali Chand Nallamothu if the 8 th nerve is good we can try retrolabyrinthinne & retrosigmoid approach & take the help of endoscope. • Post-op :
  24. 24. Posterior wall of maxillary sinus Periosteum after removal of posterior bony wall of maxillary sinus – this periosteum must be removed in JNA
  25. 25. MPP/VN LPP/V2
  26. 26. Anteriorly MPP & LPP are fused & posterioly only they are divided .
  27. 27. Anteriorly MPP & LPP are fused & posterioly only they are divided .
  28. 28. Erosion of right greater wing of sphenoid in a case of maxillary carcinoma
  29. 29. Medial pterygoid is in line with lateral wall of Sphenoid -- The superior vertical limb represents the paraclival ascending carotid and the descending vertical limb is represents the medial pterygoid plate. The horizontal bar of the ‘H’ is represented by the sphenoid sinus floor.
  30. 30. Lateral part of Posterior choanae is MPP
  31. 31. ET is just posterior to MPP
  32. 32. Lateral part of Posterior choanae is MPP
  33. 33. Medial pterygoid is in line with Paraclival carotid
  34. 34. Tracking of infraorbital nerve leads to V2 & tracking of V2 leads to Trigeminal ganglion/ Middle cranial fossa [ one of the best way to track middle crannial fossa is to track V 2 ]
  35. 35. Zygomatic nerve [ ZN ]
  36. 36. Infraorbital groove near inferior orbital fissure – If we drill supero-lateral to infraorbital nerve it is nothing but Inferior orbital fissure .
  37. 37. Infraorbital groove near inferior orbital fissure – If we drill supero-lateral to infraorbital nerve it is nothing but Inferior orbital fissure .
  38. 38. Red ring = V2
  39. 39. Inferior orbital foramen continues as pterygomaxillary fissure .
  40. 40. One line along Vidian nerve & another line along V2
  41. 41. Lateral to LPP & infra-orbital nerve [ or V2 ] is Infratemporal fossa
  42. 42. One transverse line from Vidian nerve connecting vertical line of V 2 & another transverse line from V2
  43. 43. The space above transverse line of Vidian nerve is Pterygoid Recess of sphenoid – Read the CT – scan/ Plane the surgery by using these lines
  44. 44. The space above transverse line of V2 is Middle cranial fossa ( Meckel’s cave ) – Read the CT – scan/ Plane the surgery by using these lines
  45. 45. Pterygo-palatine fossa
  46. 46. Pterygopalatine fossa. A, V2 (blue dotted line) coming out from the foramen rotundum; B, green-yellow dotted line shows the pterygopalatine ganglion; C, yellow dotted line shows the vidian nerve; D, red dotted line shows the sphenopalatine artery; E, light blue dotted line shows the great palatine nerve; F, white dotted line showing the infraorbital artery.
  47. 47. EC – Ethmoidal crest – left nose
  48. 48. PVC , VC & FR are in 45 degree angle line
  49. 49. Endoscopic view of PPG
  50. 50. Tracking of infraorbital nerve leads to V2 & tracking of V2 leads to Trigeminal ganglion/ Middle cranial fossa [ one of the best way to track middle crannial fossa is to track V 2 ]
  51. 51. Zygomatic nerve [ ZN ]
  52. 52. Endoscopic view of foramen rotundum area
  53. 53. Infratemporal fossa
  54. 54. Lateral pterygoid muscle devides internal maxillary artery into 3 parts
  55. 55. 1. The maxillary artery & Buccal nerve enters the infratemporal fossa between the superior and inferior head of the lateral pterygoid muscles. 2. Lingual nerve & Inferior alveolar nerve comes between medial pterygoid & lateral pterygoid mucles .
  56. 56. .
  57. 57. Anteriorly lingual nerve & posteriorly Inferior Alveolar nerve coming lateral to medial pterygoid muscle
  58. 58. Forceps behind IAN Forceps behind LN
  59. 59. IAN = Inferior alveolar nerve
  60. 60. Triangle formed by temporalis muscle , MPM & LPM Mandibulotomy approach Endospic view
  61. 61. Post-maxillectomy “Fat pad” over temporalis muscle – which is seen as Fat Pad [ FP ] in the triangle formed by temporalis mucle , MTM & LPM endoscopically
  62. 62. Internal carotid artery going medial & posterior to medial pterygoid muscle into Parapharyngeal space & becoming Parapharyngeal carotid
  63. 63. Internal carotid artery going medial & posterior to medial pterygoid muscle into Parapharyngeal space & becoming Parapharyngeal carotid
  64. 64. After removing the LPM you will see Tensor veli palatini muscle (TVPM) coming vertically downwards from anterior surface of ET , protecting parapharyngeal carotid & after TVPM , thick Stylopharyngeal apneurosis (SPHA ) present ANTERIOR to Parapharyngeal carotid [ So 2 structures ( TVPM & SPHA ) protecting parapharyngeal carotid ]
  65. 65. After removing the LPM you will see Tensor veli palatini muscle (TVPM) coming vertically downwards from anterior surface of ET , protecting parapharyngeal carotid & after TVPM thick Stylopharyngeal apneurosis present ANTERIOR to Parapharyngeal carotid -- Attached to this ET cartilage [ TP/ET attachment ] is the tensor palatini (TP) fibrous aponeurosis (solid white line) with its muscle fibers seen below (broken white line).
  66. 66. Hand model -- left hand = medial & lateral pterygoid right hand = index is parapharyngeal carotid , middle is IJV , ring is styloid & stylopharyngeal muscles , thumb is horizontal carotid
  67. 67. Parapharyngeal space
  68. 68. Internal carotid artery going medial & posterior to medial pterygoid muscle into Parapharyngeal space & becoming Parapharyngeal carotid
  69. 69. Post-styloid compartment = carotid space
  70. 70. Sphenoid osteum
  71. 71. Sphenoid osteum present at the juction of upper 2/3rd & lower 1/3rd junction of Superior turbinate – this became very useful to me in extensive fungal sinusitis with polyposis & bleeding.
  72. 72. Three sequential indentations are made with the blunt end of the 4-mm microdebrider blade starting at the medial upper limit of the posterior bony choana and moving directly superiorly medial to the cut edge of the superior turbinate.
  73. 73. L-OCR & M-OCR
  74. 74. L-OCR – Triangle 1. Upper boarder – Optic nerve & Opthalmic artery 2. Posterior boarder – Clinoidal carotid 3. Lower boarder – 3rd N. [ COM – Carotico-Occulomotor membrane seperates 3rd N from Clinoidal carotid ] [ 6th N. & 4th N. & V1 present inferior to 3rd N. ]
  75. 75. The optic strut has two neural- facing surfaces( yellow dotted lines) and one vascular-facing surface (red dotted line). [ COM – Carotico-Occulomotor membrane seperates 3rd N from Clinoidal carotid ]
  76. 76. The bone of the anterior clinoid (AC) process has been left in place, positioned within the lateral opticocarotid recess. L-ocr is the space in Optic strut - not the space in Anterior clinoid process
  77. 77. classification of the ophthalmic artery types http://www.springerimages.com/Images/MedicineAndPublicHealth/1- 10.1007_s10143-006-0028-6-1 a = intradural type, b = extradural supra-optic strut type [ Optic strut = L-OCR ] c = extradural trans-optic strut type on optic nerve, pr proximal ring, cdr carotid dural ring= upper dural ring , ica internal carotid artery I think this variation is type c
  78. 78. In both type a = intradural type, b = extradural supra-optic strut types Opthalmic foramen is in Optic canal
  79. 79. In Type c = extradural trans-optic strut type , the Opthalmic foramen in Optic strut
  80. 80. L-ocr is the space in Optic strut - not the space in Anterior clinoid process Note Optic strut Note Optic strut - Right Optic nerve Anterio-superior view
  81. 81. Pneumatization of anterior clinoid process – in various planes + onodi cell on both sides of sphenoid [ when transverse septum present in sphenoid it is onodi cell ] + sphenoid recess on left side between V2 & VN .
  82. 82. The same cadaver photo what you are seeing in CT scan above – Note the supraoptic pneumatisation [ present in anterior clinoid process ] in an onodi cell .
  83. 83. ICAcl clinoidal portion of the internal carotid artery , The clinoidal segment of the internal carotid artery faces the posterior aspect of the optic strut [L-OCR ]
  84. 84. Red ring – Pneumatization in Optic strut – which is nothing but L-OCR
  85. 85. M-OCR
  86. 86. Sagittal sections and superior views of the sellar region showing the optic nerve and chiasm, and carotid artery. The prefixed chiasm is located above the tuberculum. The normal chiasm is located above the diaphragma. The postfixed chiasm is situated above the dorsum.
  87. 87. 1. M-OCR is nothing but Middle Clinoid Process [ indicated by Green Button in both photos ] 2. M-OCR is the junction point of clinoidal carotid & Supra- clinoidal carotid
  88. 88. The mOCR is located just medial tothe paraclinoidal-supraclinoidal ICA transition and inferior to the distal cisternal segment of the ON(Labib et al. 2013 ). Cl clivus, ICAc cavernous portion of the internal carotid artery, ON optic nerve, PG pituitary gland, PS planum sphenoidale, TS tuberculum sellae, yellow asterisks upper dural ring, blue arrowheads lower dural ring, white asterisk lateral optico-carotid recess, white circle medial optico-carotid recess, white arrow ophthalmic artery, black arrows middle clinoid process, red arrows lateral tubercular crest, yellow arrows endocranial region corresponding to MCP
  89. 89. 1. The mOCR is placed at the confluence of the sella, tuberculum sellae, carotid protuberance, optic canal and planum sphenoidale. The mOCR corresponds to the lateral extent of the tuberculum sellae. ---- white asterisk lateral opticocarotid recess, white circle medial opticocarotid recess --- 2. The mOCR is located just medial to the paraclinoidal-supraclinoidal ICA transition and inferior to the distal cisternal segment of the ON (Labib et al. 2013 ).
  90. 90. Limits of the bone resection – Inner ring in below photo • Posterior ethmoidal arteries • Medial OCRs
  91. 91. SIS & IIS
  92. 92. Pituitary present between “ four blues” SIS – superior intercavernous sinus & IIS – inferior intercavernous sinus
  93. 93. 1. Note ASIS & PSIS 2. Note Subarachnoid space at antero-superior area , which is the potential CSF leak area in pituitary surgery . Usually the DS originates some millimeters below the TS.
  94. 94. PSIS – Posterior superior intercavernous sinus ASIS & PSIS together called CIRCULAR SINUS
  95. 95. Cavernous Sinus
  96. 96. Right cavernous sinus dissection. The quadrilateral delimits the right cavernous sinus area. a Before periosteal layer removal. b After periosteal layer removal. c Cavernous sinus compartments. L = Lateral; AI = antero- inferior; PS = posterosuperior compartment of the cavernous sinus (the medial is a virtual space in continuity with the AI and PS). CS divided into four virtual compartments: 1. medial, 2. lateral, 3. posterosuperior, and 4. anteroinferior Medial and posterosuperior compartments are in strict continuity and do not contain nerves, representing a surgical corridor without risk of neural damage. The anteroinferior and lateral compartments contain the abducens nerve and, as surgical corridors, they are exposed to the riskof injury to the VIth nerve.
  97. 97. Clivus 1. Upper Clivus 2. Middle Clivus 3. Lower Clivus
  98. 98. Basi occiput & basi sphenoid
  99. 99. Groove for medulla on Lower Clivus [ = Basi Occiput ]
  100. 100. The 6 linear landmarks of the PCF superimposed on a midsagittal T1-weighted MR imaging from a patient with CMI: herniation (HR), McRae line (MC), clivus (CL), Twining line (TW), cerebellum (CR), and supraocciput (SO). http://www.ajnr.org/content/34/9/1758.figures- only?cited-by=yes&legid=ajnr;34/9/1758
  101. 101. 1. Upper clivus – Upto 6th nerve entry dorello’s canal (petro-clival junction) 2. Middle clivus – from 6th nerve to jugular foramen 3. Lower clivus – from jugular foramen to foramen magnum
  102. 102. Pneumatization of the sphenoid sinus
  103. 103. The middle third (M. 1/3rd) begins at the sella floor (SF) and extends to the floor of the sphenoid sinus (SSF), and the lower third (L. 1/3rd) extends from the floor of the sphenoid sinus to the foramen magnum (FM).
  104. 104. Pregnant of upper clivus is Sella
  105. 105. Infrapetrous Approach Carotid-Clival window – Mid clivus a. Petrosal face b.Clival face
  106. 106. See the lower clivus relation to the cochlea
  107. 107. In conchal sphenoid surgical landmarks – 1. posterior end of vomer or keel of sphenoid tells about the position of pituitary 2. lateral boarder of posterior choana [ or MPP ]tells about paraclival carotid & sellar carotid C-SHAPE convex is lateral to this line 3. posterior lower boarder of vomer is at the junction of middle & lower 1/3rd clivus & it is exactly at foramen lacerum –my understanding
  108. 108. See the relationship between lower boarder of posterior end of vomer & clivus – vomer lower boarder is at junction of mid & lower clivus – my understanding
  109. 109. http://www.neurosurgicalapproaches. com/2013/08/25/
  110. 110. Anterior cranial fossa dura Posterior cranial fossa dura
  111. 111. Very rare specimen..The vbj is far inferior to floor of sphenoid sinus
  112. 112. The foramen lacerum (FL) is located lateral to the floor of the sphenoid sinus at the level of the spheno-petro-clival confuence. JT jugular tubercle, HC hypoglossal canal – addFig 3.78 also
  113. 113. Infrapetrous Approach Carotid-Clival window – Mid clivus a. Petrosal face b.Clival face
  114. 114. When we are drilling lower clivus – lateral to hypoglossal canal we get Jugular fossa
  115. 115. Inferior clival line (Fernandez-Miranda et al. 2012 ) The longus capitis and rectus capitis anterior muscle attach on the inferior surface of the clivus. Below the RCAM the occipito-cervical joint capsule lies. The area of attachement of the RCAM has been named inferior clival line (Fernandez-Miranda et al. 2012 ) and correspond to the supracondylar groove (that is a landmark for the hypoglossal canal).
  116. 116. Transcochlear approach
  117. 117. Note CL [ Lower clivus ] in these photos after drilling of cochlea
  118. 118. Note CL [Lower clivus ] in these photos after drilling of cochlea The clivus bone (CL) can be seen medial to the internal carotid artery (ICA). JB Jugular bulb In the lower part of the approach, the glossopharyngeal nerve (IX) can be seen. V Trigeminal nerve, VIII Cochlear nerve, AICA Anterior inferior cerebellar artery, CL Clivus bone, DV Dandy’s vein, FN Facial nerve, FN(m) Mastoid segment of the facial nerve, FN(t) Tympanic segment of the facial nerve, GG Geniculate ganglion, ICA Internal carotid artery, JB Jugular bulb, MFD Middle fossa dura, SCA Superior cerebellar artery, SS Sigmoid sinus
  119. 119. Note CL [Lower clivus ] in these photos after drilling of cochlea BT- basal turn of the cochlea Fig. 8.34 The bone medial to the internal carotid artery (ICA) has been drilled and the clivus bone (CL) has been reached. FN Facial nerve, JB Jugular bulb
  120. 120. Note CL [Lower clivus ] in these photos after drilling of cochlea Note cochlear aqueduct [ CA ] Here ICA is vertical part of carotid infront to cochlea – this is not paraclival carotid
  121. 121. Note CL [ clivus ] in these photos after drilling of cochlea
  122. 122. Note CL [Lower clivus ] in these photos after drilling of cochlea Note the contralateral vertebral artery [ CVA ] in below photo
  123. 123. Lower clivus in Infratemporal fossa approach
  124. 124. PVC – is occupied by Ascending palatine artery (APA)
  125. 125. Craniopharyngioma removal - Lilliquest membrane & Basillar artery
  126. 126. V3 & MMA
  127. 127. V 3 falls like niagara falls from middle cranial fossa to infratemporal fossa 90 degrees away from V1 & V2 – it is anterior to all the 3 structures , Petrous carotid & ET tube & Parapharyngeal carotid
  128. 128. ATN = Auriculotemporal nerve
  129. 129. MMA
  130. 130. IAN = Inferior alveolar nerve
  131. 131. My forceps touched the lingual nerve , posterior to this LN is Inferior alveolar nerve – These two nerves present in triangle formed by medial pterygoid , lateral pterygoid & temporalis muscle
  132. 132. Chorda[CT] attached to LN
  133. 133. Chorda[CT] attached to LN
  134. 134. Schematic diagram for infratemporal fossa approach
  135. 135. Sometimes V3 can be seen in the sphenoid sinus – in “pneumosinus dilatans multiplex”
  136. 136. The greater wing of sphenoidal is almost completely pnematised. So is the temporal bone on the left.the Left carotid can be traced from the middle ear to the sphenoid - in “pneumosinus dilatans multiplex”
  137. 137. V3 & MMA
  138. 138. V3 & MMA
  139. 139. V3[MN] & MMA & ET in lateral & Anterior skull base – see the relationship of ET tube which is medial to V3 & MMA
  140. 140. Posterior boarder of Lateral pterygoid bone leads to Foramen Ovale [ FO ] – Dr.Kuriakose
  141. 141. Posterior boarder of Lateral Pterygoid bone leads to Foramen Ovale [ FO ] – Dr.Kuriakose
  142. 142. Endoscopically [ Anterior skull base ] if we follow upper end of LPT posteriorly we can reach V3 [ Posterior boarder of Lateral Pterygoid bone leads to Foramen Ovale – Dr.Kuriakose ]
  143. 143. In Infratemporal fossa approach- Posterior boarder of Lateral pterygoid bone leads to Foramen Ovale [ FO ] – Dr.Kuriakose
  144. 144. V3 is anterior (infront) to Horizontal carotid (= Petrous carotid ) & ET – It cause indentation on the ET also .
  145. 145. In open approaches in maxillary swing approach as long as you stay lateral to ET you will not injure the horizontal part of carotid
  146. 146. Petrous carotid & paraclival carotid is SADDLE shape – LEG of the rider is V3
  147. 147. V 3 is anteriror to all the 3 structures - Petrous carotid & ET & Parapharyngeal carotid [ very imp ]
  148. 148. Cochlea in anterior skull base b is cochlea in middle cranial fossa – cochlear angle between GSPN & IAC
  149. 149. V3 is an important landmark to locate the post-styloid compartment, as it is anterior to this space (Falcon et al. 2011 ) .
  150. 150. TP & LP
  151. 151. See the relationship of MPP & TP which is just posterior
  152. 152. Sinus of Morgagni - In nasopharyngeal carcinoma, the tumor may extend laterally and involve this sinus involving the Mandibular nerve. This produces a triad of symptoms known as Trotter's triad [ 1) Conductive deafness ( due to eustachian tube involvement) 2) Ipsilateral immobility of soft palate 3) Neuralgic pain in the distribution of V3 ]
  153. 153. See the relationship between LPP & V3 which is just posterior
  154. 154. Eustachian tube
  155. 155. ET is just posterior to MPP [ Lateral part of Posterior choanae is MPP ]
  156. 156. ET is just posterior to MPP
  157. 157. ET is pointing like an ARROW the posterior genu of internal carotid [ ICAp & CF is parapharyngeal carotid ]
  158. 158. Sinus of Morgagni - In nasopharyngeal carcinoma, the tumor may extend laterally and involve this sinus involving the Mandibular nerve. This produces a triad of symptoms known as Trotter's triad [ 1) Conductive deafness ( due to eustachian tube involvement) 2) Ipsilateral immobility of soft palate 3) Neuralgic pain in the distribution of V3 ]
  159. 159. black asterisks medial corridor to ICAp – TVPM attached to anterior surface of ET – so if we go inbetween MPM & TVPM we reach to ICAp
  160. 160. Bony-cartilagenous junction of ET tube is at posterior genu of carotid - ET is pointing like an ARROW the posterior genu of internal carotid
  161. 161. Yellow arrow - Bony-cartilagenous junction of ET tube is at posterior genu of carotid - ET is pointing like an ARROW the posterior genu of internal carotid
  162. 162. V 3 is anteriror to all the 3 structures - Petrous carotid & ET & Parapharyngeal carotid [ very imp ]
  163. 163. ET tube in SPF [Spheno-petrosal fissure]
  164. 164. At bony-cartilagenous junction of ET tube – Horizonal carotid & Parapharyngeal carotid is above & below ET - My understanding
  165. 165. In open approaches in maxillary swing approach as long as you stay lateral to ET you will not injure the horizontal part of carotid
  166. 166. Fossa of Rossenmuller apex is laceral carotid [ Foramen Lacerum ] pharyngeal recess (fossa of Rosenmüller), which projects laterally from the posterolateral corner of the nasopharynx with its lateral apex facing the internal carotid artery laterally and the foramen lacerum above;
  167. 167. endonasal approaches to expose the area between the ICAs belong to the sagittal plane, and the approaches around the ICA define the coronal plane modules.
  168. 168. Note that the eustachian tube indicates the carotid canal only approximately. In other words, it lies on a different CORONAL plane in respect of the vessel, and from an anterior viewpoint, it covers the vessel for all its length. -- Medially the space between these two CORONAL planes is nothing but Fossa of Rosenmuller [ My understanding ]
  169. 169. Note that the eustachian tube indicates the carotid canal only approximately. In other words, it lies on a different CORONAL plane in respect of the vessel, and from an anterior viewpoint, it covers the vessel for all its length. -- Medially the space between these two CORONAL planes is nothing but Fossa of Rosenmuller [ My understanding ]
  170. 170. Surgeons should have in mind that the external orifi ce of the carotid canal is not on the same coronal plane of the foramen lacerum (anterior genu). It is by far more posteriorly located.
  171. 171. SOF [ Superior Orbital Fissure ]
  172. 172. Parts of SOF 1. Lateral part- LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal N.,Trochlear N. 2.Middle part 3. Medial/Inferior part
  173. 173. Parts of SOF 1. Lateral part- LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal N.,Trochlear N. 2.Middle part 3. Medial/Inferior part
  174. 174. Accessing intraconal lesions endonasally requires manipulation of the extraocular muscles. The nerve branches that supply the oculomotor muscles run in the medial surface of the muscles. Thus, try to avoid excessive retraction of the extraocular muscles to avoid inadvertent muscle paresis.
  175. 175. SOF is the space between two Structs – Superiorly OS [ Optic Strut ] & Inferiorly MS [ Maxillary Strut ]
  176. 176. SOF is the space between two Structs – Superiorly OS [ Optic Strut ] & Inferiorly MS [ Maxillary Strut ]
  177. 177. SOF is the space between two Structs – Superiorly OS [ Optic Strut ] & Inferiorly MS [ Maxillary Strut ] Anterior view of SOF Posterior view of SOF
  178. 178. Yellow line = “nasal” part of SOF Clinically, the SOF and CS apex represents a continuum.
  179. 179. endoscopic endonasal viewpoint the nasal window to SOF is above V2, and below the lateral optico-carotid recess. blue-sky arrows SOF ; MS-Maxillary strut ; MP-Maxillary prominence
  180. 180. Zonule of zinn - inserts on the infraoptic tubercle, which is often found as a canal located beneath the optic strut .
  181. 181. The structure Infero-lateral to SOF is – Horizontal part of carotid
  182. 182. Anterior to L-OCR is Superior Orbital Fissure
  183. 183. SOF - Anterior
  184. 184. SOF - Posterior
  185. 185. MS- Maxillary strut /// Average distance from the FR at PPF and the vertical segment of ICAc is 35 mm [ 3.5cm ] (Amin et al. 2010 ) .
  186. 186. SOF , Middle Fossa , V3 in line vertically
  187. 187. GSPN-VIDIAN NERVE
  188. 188. GSPN passes above Horizontal [=petrous] carotid & passes underneath V3 & crosses petro-paraclival carotid junction at foramen lacerum before becoming vidian nerve
  189. 189. The bone overlying the internal auditory canal has been removed and the dura of the canal has been removed near the fundus. The facial nerve (FN) can be seen entering its labyrinthine segment to form the geniculate ganglion (GG) more laterally. V Trigeminal nerve, < Acousticofacial bundle, C Cochlea, ET Eustachian tube, GPN Greater petrosal nerve, I Incus, IAC Internal auditory canal, ICA Internal carotid artery, M Malleus, SSC Superior semicircular canal, SV Superior vestibular nerve Observe the relationship between GSPN & horizontal carotid
  190. 190. Fig. 2.62 The course of the horizontal segment of the internal carotid artery (ICAh), as seen from the middle cranial fossa of a left temporal bone. VI Abducent nerve, C Cochlea, GPN Greater petrosal nerve, IAC Internal auditory canal, ICA(ic) Intracranial internal carotid, M Mandibular nerve, MMA Middle meningeal artery, MX Maxillary nerve
  191. 191. Fig. 5.47 The view after completion of the middle crannial fossa approach. AE Arcuate eminence, BB Bill’s bar, C Cochlea, FN(iac) Internal auditory canal segment of the facial nerve, FN(t) Tympanic segment of the facial nerve, G Geniculate ganglion, GPN Greater petrosal nerve, I Body of the incus, L Labyrinthine segment of the facial nerve, M Head of the malleus, MFD Middle fossa dura, SVN Superior vestibular nerve
  192. 192. In Infratemporal fossa - Note that the greater petrosal nerve (GPN) is adherent to the dura, and that retracting the dura will lead to stress on the facial nerve at the geniculate ganglion (GG) level. Thus, if dural retraction is needed, cutting the petrosal nerve will prevent this injury. In middle cranial fossa – same point
  193. 193. Foramen lacerum AFL = Anterior foramen lacerum * [ black asterisk ] = foramen lacerum Petrolingual area = foramen lacerum
  194. 194. After elevating V3 anterior[infront] to ET & petrous carotid observe -- GSPN continues as VN [ VN is lateral to paraclival carotid ]
  195. 195. GSPN & GSPN groove in Surpra petrous window ET eustachian tube, GPN greater petrosal nerve, MCFd dura of the middle cranial fossa, MMA middle meningeal artery, SPS superior petrosal surface, TI trigeminal impression, V3 third branch of the trigeminal nerve, yellow arrow accessory middle meningeal artery, white asterisks greater petrosal nerve groove
  196. 196. Vidian nerve is formed by GSPN & Deep petrosal nerve – so GSPN (passes underneath V3) crosses laterally the Horizontal carotid and paraclival carotid junction (Prof.Kassam) & continues as Vidian nerve Blue arrow – LPN & Yellow arrow – GPN
  197. 197. Trans-pterygoid approch-- Vidian Artery present in 60% & enters at the junction of Horizontal carotid & paraclival carotid – it is present above the Vidian nerve so while drilling vidian canal in JNA first we have to drill inferior half and then upper half [the bone around the vidian canal is drilled along its inferior half (from 3 o’clock to 9 o’clock) until the carotid artery is identified at the lacerum segment ]
  198. 198. Vidian nerve - lateral to paraclival carotid & medial to FO [ Foramen Ovale ]- actually it is GSPN
  199. 199. Vidian canal & Spheno-palatine foramen are in 90 degrees
  200. 200. Vidian nerve - lateral to paraclival carotid
  201. 201. Vidian nerve - lateral to paraclival carotid
  202. 202. Vidian nerve - lateral to paraclival carotid
  203. 203. Vidian nerve - lateral to paraclival carotid Close vision of the middle cranial fossa. The gasserian ganglion has been removed
  204. 204. Vidian nerve - lateral to paraclival carotid
  205. 205. Axial T2-weighted magnetic resonance imaging (MRI) sequence at the level of the vidian canal: 1, clivus; 2, pterygoid; 3, horizontal tract of the internal carotid artery (ICA); 4, vidian canal.
  206. 206. The space between V1 & V 2 and V2 & V3 is sphenoid sinus Middle cranial fossa approach – the nerve between V2 & V3 is VN Anaterior skull base
  207. 207. Infratemporal fossa approach type C Middle cranial fossa approach – the nerve between V2 & V3 is VN
  208. 208. Foramen lacerum AFL = Anterior foramen lacerum * [ black asterisk ] = foramen lacerum Petrolingual area = foramen lacerum
  209. 209. Vidian artery – origin from Laceral segment
  210. 210. Lateral Recess is the space between V2 & Vidian nerve .
  211. 211. Courtesy – Dr. Satish Jain , Jaipur
  212. 212. Lateral Recess is the space between V2 & Vidian nerve .
  213. 213. Here TI [ trigeminal impression ] is V2
  214. 214. LRSS = Lateral recess of the sphenoid sinus
  215. 215. Floor of Lateral recess is by ET ---- BS basisphenoid, ET eustachian tube, LRSS lateral recess of the sphenoid sinus, OPPB orbital process of the palatine bone, PVA(s) palatovaginal artery(ies), RPm rhinopharyngeal mucosa, SPAib inferior branch of the sphenopalatine artery, SPPB sphenoidal process of the palatine bone, SS sphenoid sinus, RS rostrum sphenoidale, VN vidian nerve
  216. 216. Surpra petrous window ET eustachian tube, GPN greater petrosal nerve, MCFd dura of the middle cranial fossa, MMA middle meningeal artery, SPS superior petrosal surface, TI trigeminal impression, V3 third branch of the trigeminal nerve, yellow arrow accessory middle meningeal artery, white asterisks greater petrosal nerve groove
  217. 217. Carotid nerve
  218. 218. Middle cranial fossa approach
  219. 219. The middle fossa retractor is fixed at the petrous ridge (PR). AE Arcuate eminence, GPN Greater petrosal nerve, M Middle meningeal artery The expected location of the internal auditory canal (IAC). The bar-shaded areas are the locations for drilling. A Anterior, AE Arcuate eminence, GPN Greater petrosal nerve, MMA Middle meningeal artery, P Posterior
  220. 220. Petrous apex bone
  221. 221. Petrous apex - Quadrangular area
  222. 222. Petrous apex – Triangular area
  223. 223. Triangles
  224. 224. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-cavernous-sinus- cadaver-study - Endoscopic view of the right cavernous sinus and neurovascular relations, demonstrating the ‘S’ shaped configuration formed by the oculomotor, the abducens and the vidian nerves. III oculomotor nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3 mandibular nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend of the internal carotid artery–parasellar segment, ICA-Sp posterior bend of the internal carotid artery–parasellar segment, ICA-C paraclival segment of the internal carotid artery, ICA-L lacerum segment of the internal carotid artery, ICA-P petrous segment of the internal carotid artery, PG pituitary gland, VC vidian canal, VN vidian nerve 6th nerve is parallel to V1 – in the same direction of V1
  225. 225. 6th nerve is parallel to V1 – in the same direction of V1
  226. 226. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the- cavernous-sinus-cadaver-study- Endoscopic view of the right cavernous sinus and its neurovascular relations, demonstrating the triangular area formed by the medial pterygoid process laterally, the parasellar ICA medially and the vidian nerve inferiorly at the base. III oculomotor nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3 mandibular nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend of the internal carotid artery–parasellar segment, ICA-Sp posterior bend of the internal carotid artery–parasellar segment, ICA-C paraclival segment of the internal carotid artery, ICA- L lacerum segment of the internal carotid artery, ICA-P petrous segment of the internal carotid artery, PG pituitary gland, VC vidian canal, VN vidian nerve
  227. 227. 1.Supra Trochanteric & Infratrochanteric Triangles 2. Upper & lower dural rings
  228. 228. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-cavernous- sinus-cadaver-study -Endoscopic view of the right cavernous sinus showing its neurovascular relations and the main anatomic areas. III oculomotor nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3 mandibular nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend of the internal carotid artery–parasellar segment, ICA Sp posterior bend of the internal carotid artery–parasellar segment, ICA-C paraclival segment of the internal carotid artery, ICA-L lacerum segment of the internal carotid artery, ICA-P petrous segment of the internal carotid artery, PG pituitary gland, VC vidian canal, VN vidian nerve, STA superior triangular area, SQA superior quadrangular area, IQA inferior quadrangular area 1.Supra Trochanteric & Infratrochanteric Triangles 2. Upper & lower dural rings
  229. 229. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the- cavernous-sinus-cadaver-study - Endoscopic view (a), and a drawing (b) of the right cavernous sinus demonstrating its neurovascular relations. c A drawing of the right cavernous sinus demonstrating the exposure of the trochlear nerve after retracting the oculomotor nerve. III oculomotor nerve, IV trochlear nerve, V1 ophthalmic nerve, VI abducens nerve, ICA internal carotid artery, OA ophthalmic artery, OCh optic chiasm, ON optic nerve, PG pituitary gland
  230. 230. Triangles of Middle cranial fossa – see Ant. Medial & Ant. Lateral triangles in both photos. http://www.eneurosurgery.com/surgicaltrianglesofthecavernoussinus.html Postero-medial Triangle = KAWASE triangle [Prof.KAWASE , JAPAN Neurosurgeon -below photo]
  231. 231. Fig. 22.31 Clinoidal and oculomotor triangles have been opened and the anterior clinoid removed up to the optic strut, exposing the carotido- oculomotor membrane. The optic strut has two neural-facing surfaces( yellow dotted lines) and one vascular-facing surface (red dotted line). CN: cranial nerve; Falc.: falciform; ICA: internal carotid artery; Inf.:inferior; Lig.: ligament; Pet.: petrosal; V1: first division; V2: second division; V3: third division of trigeminal nerve. ACP anterior clinoid process, APCF anterior petroclinoid fold, DS dorsum sellae, ICF interclinoid fold, PF pituitary fossa, PLL petrolingual ligament (inferior sphenopetrosal ligament), PPCF posterior petroclinoid fold, PS planum sphenoidale, SSPL superior sphenopetrosal ligament (Gruber’s ligament), TS tuberculum sellae, black asterisk middle clinoid process
  232. 232. Opticocarotid traiangle by Pterional approach
  233. 233. CAROTID
  234. 234. KISSING CAROTIDS 1. http://radiopaedia.org/articles/kissing-carotids 2. http://www.ncbi.nlm.nih.gov/pubmed/17607445 • The term kissing carotids refers to tortuous and elongated vessels which touch in the midline. They can be be found in: • retropharynx 2 • intra-sphenoid 1 – within the pituitary fossa – within sphenoid sinuses – within sphenoid bones • The significance of kissing carotids is two-fold: – may mimic intra-sellar pathology – catastrophic if unknown or unreported before transsphenoidal / retropharyngeal surgery
  235. 235. Cervical kissing carotids – here also papaphayrngela kinking present http://www.radrounds.com/photo/cervical-kissing- carotids-1 Coronal MIP of aberrant medial course of the carotids arteries showing the internal carotids arteries nearly touching at the C2 level.
  236. 236. An Aberrant Cervical Internal Carotid Artery in the Mouth http://amjmed.org/an-aberrant-internal-carotid-artery-in-the-mouth/
  237. 237. Intrasellar kissing carotid arteries -This anomaly is particularly important since it may cause or mimic pituitary disease and also may complicate transsphenoidal surgery.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004- 282X2007000200034&lng=en&nrm=iso&tlng=en
  238. 238. Looping / Kinking of Parapharyngeal carotid
  239. 239. kinking or looping of the ICAp - when looping present para-pharyngeal carotid comes to pre-styloid compartment – previously thought that para-pharyngeal carotid never comes anterior to styloid mucles – which is UNTRUE
  240. 240. The stylopharyngeus and styloglossus muscles are critical landmarks, being usually placed anterior to the great vessels (Dallan et al. 2011 ). Note that the presence of kinking or looping of the ICAp could make this statement untrue.
  241. 241. Cervical kissing carotids – here also papaphayrngela kinking present http://www.radrounds.com/photo/cervical-kissing- carotids-1 Coronal MIP of aberrant medial course of the carotids arteries showing the internal carotids arteries nearly touching at the C2 level.
  242. 242. An Aberrant Cervical Internal Carotid Artery in the Mouth http://amjmed.org/an-aberrant-internal-carotid-artery-in-the-mouth/
  243. 243. In this kinking of ICA also Prof.Mario Sanna uses very flexible ICA stents
  244. 244. Relation of Eustachian tube & looping of parapharyngeal carotid & styloid process
  245. 245. The external carotid artery passes deeply to the digastric and stylohyoid muscles, but superficially to the stylopharyngeus and styloglossal muscle when running toward the parotid gland (Janfaza et al. 2001 ) .
  246. 246. Intratemporal carotid = Horizontal carotid[= Petrous carotid] + Vertical carotid
  247. 247. Endoscopic view of the eustachian tube orifice (arrow).- Note Internal carotid artery
  248. 248. In Infra-temporal fossa approach The full course of the intratemporal internal carotid artery has been freed. AFL Anterior foramen lacerum, CF Carotid foramen, CL Dura overlying the clivus area, ICA(h) Horizontal segment of the internal carotid artery, ICA(v) Vertical segment of the internal carotid artery, MN Stump of the mandibular nerve Drilling of the clivus has been completed. C Basal turn of the cochlea (promontory), FN(m) Mastoid segment of the facial nerve, FN(t) Tympanic segment of the facial nerve, GG Geniculate ganglion, GPN Greater petrosal nerve, ICA Internal carotid artery, RW Round window
  249. 249. Pterygoid trigone – just anterior to foramen lacerum in both photos is Pterygoid trigone
  250. 250. Note the Cochlea basal turn anterior wall in left photo
  251. 251. Note that the basal turn of the cochlea (BT) starts to curve superiorly near the internal carotid artery (ICA), a short distance from the level of the round window.
  252. 252. In most cases, the medial aspect of the horizontal portion of the internal carotid artery is not covered by bone, but simply by dura.
  253. 253. GSPN bisects the Petrous carotid & V3 and Vertical part of Facial nerve bisects Jugular bulb
  254. 254. In most cases, the medial aspect of the horizontal portion of the internal carotid artery is not covered by bone, but simply by dura.
  255. 255. Post-operative vasospasm of laceral segment [ carotid mobilization done for tumor removal ]
  256. 256. Paraclival carotid
  257. 257. TG ( Trigeminal ganglion ) is lateral to Paraclival carotid
  258. 258. Infrapetrous Approach Carotid-Clival window – Mid clivus a. Petrosal face b.Clival face
  259. 259. After drilling the carotid canal what we see is endosteal layer , not directly the ICA – Dr.Janakiram Subperiosteal/Subadventitial Dissection Subperiosteal/subadventitial dissection is accomplished for tumors that involve the ICA to a greater extent, such as C2 glomus tumors and meningiomas (Fig. 15.24a, b). In general, dissection of the tumor from the artery is relatively easier and safer in the vertical intrapetrous segment, which is thicker and more accessible than the horizontal intrapetrous segment. A plane of cleavage between the tumor and the artery should be found first. In most cases, the tumor is attached to the periosteum surrounding the artery. Dissection is better started at an area immediately free of tumor. Aggressive tumors may, however, extend even to the adventitia of the artery and subadventitial dissection may be needed. This should be done very carefully in order to avoid any tear to the arterial wall, which can become weakened (Fig. 15.25), with the risk of subsequent blowout.
  260. 260. Fig. 15.25 A case of left glomus jugulare tumor in our early experience. Subadventitial dissection has been performed because the artery had been so weakened after the tumor removal. Although the patient had no relevant complications postoperatively, such excessive manipulation is better avoided and permanent balloon occlusion or stenting are preferably tried preoperatively.
  261. 261. Meckels cave - Trigeminal notch at petrous apex
  262. 262. Carotid nerve
  263. 263. Petrolingual ligament [ PLL ] & Foramen Lacerum [ FL ]
  264. 264. Lingula of sphenoid
  265. 265. Lingula of sphenoid
  266. 266. Lingula of sphenoid red asterisk = lingula of the sphenoid black arrowhead = lingula of the sphenoid
  267. 267. PLL- Petrolingual ligament - considered as a continuation of the periostium of the carotid canal (Osawa et al. 2008 ) .
  268. 268. Infrapetrous Approach Carotid-Clival window – Mid clivus a. Petrosal face b.Clival face
  269. 269. “Front door” to Meckel’s cave PLL - It can be considered the border between the horizontal and cavernous portions of the internal carotid artery.
  270. 270. Nerves in lateral wall of cavernous in JNA case
  271. 271. Foramen lacerum - The petrous ICA then curves upward above the foramen lacerum (FL), thus giving the anterior genu. The segment above the FL is not truly intrapetrous, and it has been called the lacerum segment by some authors (Bouthillier et al. 1996 ) . These segments, the anterior genu and the anterior vertical segment, are placed above the FL, and the artery does not cross the foramen. In this sense, it is better called the supralacerum segment (Herzallah and Casiano 2007 ) . Anatomically, the FL is an opening in the dry skull that in life is fi lled by fi brocartilagineous tissue (fi brocartilago basalis). AFL = Anterior foramen lacerum * [ black asterisk ] = foramen lacerum Petrolingual area = foramen lacerum
  272. 272. Vidian artery – origin from Laceral segment
  273. 273. 1. The foramen lacerum (FL) is located lateral to the floor of the sphenoid sinus at the level of the spheno-petro-clival confuence. 2. In respect to the FL, the JT is postero-medially located. Therefore to access the jugular tubercle from anteriorly a complete exposure of the foramen lacerum is needed. black asterisk foramen lacerum , JT jugular tubercle, HC hypoglossal canal
  274. 274. PLL = INFERIOR SPHENOPETROSAL LIGAMENT ACP anterior clinoid process, APCF anterior petroclinoid fold, DS dorsum sellae, ICF interclinoid fold, PF pituitary fossa, PLL petrolingual ligament (inferior sphenopetrosal ligament), PPCF posterior petroclinoid fold, PS planum sphenoidale, SSPL superior sphenopetrosal ligament (Gruber’s ligament), TS tuberculum sellae, black asterisk middle clinoid process
  275. 275. Parasellar carotid
  276. 276. Parasellar carotid – shrimp shaped It covers four segments of the ICA: (1) the hidden segment; (2) the inferior horizontal segment; (3) the anterior vertical segment, and (4) the superior horizontal segment. The hidden segment is located at the level of the posterior sellar floor and includes the posterior bend of the ICA. The inferior horizontal segment appears short due to the perspective view, but is the longest segment of the intracavernous ICA. It courses along the sellar floor. The anterior vertical segment corresponds to the convexity of the C- shaped parasellar protuberance. The superior horizontal segment includes the clinoidal segment which courses medially to the optic strut, is anchored by the proximal and distal dural ring and continues in the subarachnoid portion of the vessel.
  277. 277. Retro, Infra, Presellar prominences
  278. 278. A) Cadaveric dissection image taken within the sphenoid sinus, with removal of bone over the lateral sphenoid wall. The paraclival carotid artery (PCA) enters the base of the sphenoid sinus and runs in a vertical direction. At approximately the level of the V2 (maxillary division of trigeminal nerve) the carotid artery then enters the cavernous sinus and becomes the intracavernous carotid artery (CCA). Once the artery enters the cavernous sinus it continues to ascend for a short distance, called the vertical portion of the CCA (V. CCA), before turning anteriorly at the posterior genu of the CCA (P. Genu CCA). This posterior genu corresponds to the floor of the sella. The artery then runs horizontally as the horizontal portion of the CCA (H. CCA), before reaching the anterior
  279. 279. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the- cavernous-sinus-cadaver-study- Endoscopic view of the right cavernous sinus and its neurovascular relations, demonstrating the triangular area formed by the medial pterygoid process laterally, the parasellar ICA medially and the vidian nerve inferiorly at the base. III oculomotor nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3 mandibular nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend of the internal carotid artery–parasellar segment, ICA-Sp posterior bend of the internal carotid artery–parasellar segment, ICA-C paraclival segment of the internal carotid artery, ICA- L lacerum segment of the internal carotid artery, ICA-P petrous segment of the internal carotid artery, PG pituitary gland, VC vidian canal, VN vidian nerve
  280. 280. Branches of cavernous carotid 1. Meningohypophyseal trunk 2. Inferolateral trunk The anterior lobe of the pituitary gland is mainly fed by the superior hypophyseal arteries while the posterior lobe is fed mainly by the inferior hypophyseal artery. Branches of Intracranial carotid 1. Superior hypophyseal Artery
  281. 281. Superior Hypophyseal Arteries [ SHAs ]
  282. 282. The anterior lobe of the pituitary gland is mainly fed by the superior hypophyseal arteries while the posterior lobe is fed mainly by the inferior hypophyseal artery.
  283. 283. Superior Hypophyseal Arteries [ SHAs ] - more commonly arise from the paraclinoid ICA - In rare cases SHAs originate from the intracavernous segment of the ICA
  284. 284. Meningohypophyseal trunk
  285. 285. The MHT is traditionally described as having three branches: 1. the inferior hypophyseal artery, IHA 2. the dorsal meningeal artery (also called the dorsal clival artery) DMA, and 3. the tentorial artery (also called the Bernasconi-Cassinari artery) BCA .
  286. 286. At superior part of Siphon carotid , SHA arises where as inferior part of Siphon carotid MHT [ Inferior hypophyseal artery ] arises
  287. 287. DMA main feeder of dorellos segement of 6th nerve DMA main feeder of dorellos segement of 6th nerve
  288. 288. Inferolateral trunk
  289. 289. Inferolateral trunk
  290. 290. In most cases ILT passes superiorly to the abducens nerve (Inoue et al. 1990 ; Jittapiromsak et al. 2010 ) .
  291. 291. In most cases ILT passes superiorly to the abducens nerve (Inoue et al. 1990 ; Jittapiromsak et al. 2010 ) .
  292. 292. Cholesterol granuloma
  293. 293. cholesterol granuloma immediately behind the ICA
  294. 294. ICA Clin.: clinoid, clinoidal
  295. 295. Dural rings – the ICA between upper & lower dural ring is Clinoidal ICA
  296. 296. Cl clivus, ICAc cavernous portion of the internal carotid artery, ON optic nerve, PG pituitary gland, PS planum sphenoidale, TS tuberculum sellae, yellow asterisks upper dural ring, blue arrowheads lower dural ring, white asterisk lateral optico-carotid recess, white circle medial optico-carotid recess, white arrow ophthalmic artery, black arrows middle clinoid process, red arrows lateral tubercular crest, yellow arrows endocranial region corresponding to MCP
  297. 297. Lower dural ring is nothing but COM [ Carotico-occulomotor membrane ] - The dura lining the inferior aspect of the anterior clinoid process forms the lower dural ring. This ring is often incomplete on the medial side and often a venous channel can follow the paraclinoidal ICA to the upper dural ring. By Fronto temporal approach
  298. 298. lower dural ring - This ring is often incomplete on the medial side and often a venous channel can follow the paraclinoidal ICA to the upper dural ring.
  299. 299. blue-sky arrow = upper dural ring,
  300. 300. The lower dural ring is given by the COM [ Carotid-oculomotor membrane ] , that lines the inferior surface of the ACP. It can be visible, through a transcranial route, only by removing the ACP. The lower dural ring is also called Perneczky’s ring. Medially the COM blends with the dura that lines the carotid sulcus (Yasuda et al. 2005 ) Endoscopic supraorbital view with a 30° down-facing lens -The right portion of the planum sphenoidale is seen from above. Right side
  301. 301. Upper & lower dural rings
  302. 302. 1.Supra Trochanteric & Infratrochanteric Triangles 2. Upper & lower dural rings
  303. 303. ICAcl clinoidal portion of the internal carotid artery , The clinoidal segment of the internal carotid artery faces the posterior aspect of the optic strut. white arrowhead - paraclinoid portion of the internal carotid artery – after removal of anterior clinoidal process
  304. 304. ICA Clin.: clinoid, clinoidal [ Observe here also – posterior border of Optico- carotid recess is Clinoidal ICA ]
  305. 305. ICA Clin.: clinoid, clinoidal
  306. 306. ICA Clin.: clinoid, clinoidal
  307. 307. ICA Clin.: clinoid, clinoidal
  308. 308. ICA Clin.: clinoid, clinoidal
  309. 309. Intracranial portion of ICA [ICA i]
  310. 310. The mOCR is located just medial to the paraclinoidal-supraclinoidal ICA transition and inferior to the distal cisternal segment of the ON(Labib et al. 2013 ). Cl clivus, ICAc cavernous portion of the internal carotid artery, ON optic nerve, PG pituitary gland, PS planum sphenoidale, TS tuberculum sellae, yellow asterisks upper dural ring, blue arrowheads lower dural ring, white asterisk lateral optico-carotid recess, white circle medial optico-carotid recess, white arrow ophthalmic artery, black arrows middle clinoid process, red arrows lateral tubercular crest, yellow arrows endocranial region corresponding to MCP
  311. 311. Opthalmic artery – Retrograde branch of Intracranial carotid Branches of the cavernous internal carotid artery ( ICA ), a rare variation: ophthalmic artery passing through the superior orbital fissure
  312. 312. In the lateral border of the chiasmatic cistern the first part of the ICAi is visible. Note Optic tract here which is above Posterior clinoid process [ PCP ]
  313. 313. Supra-clinoidal carotid=1st part of intracranial carotid
  314. 314. APAs anterior perforating arteries, ICAi intracranial portion of the internal carotid artery, OT optic tract, SF Sylvian fi ssure,
  315. 315. ACA anterior cerebral artery, APAs anterior perforating arteries, FOA fronto-orbital artery, FOV fronto-orbital vein, FPA fronto-polar artery, ICAi intracranial segment of the internal carotid artery, MCA middle cerebral artery, OlfT olfactory tract, OlfV olfactory vein, ON optic nerve, PS pituitary stalk, TL temporal lobe, black asterisk anterior communicating artery
  316. 316. ICA dividing into ACA and MCA
  317. 317. Optic tract [ OT ]
  318. 318. Pterional
  319. 319. CRANIOPHARYNGIOMAS-Removal corridors.
  320. 320. Cyst of craniopharyngioma
  321. 321. Surpra petrous approach
  322. 322. Surpra petrous window [ see the GSPN groove here ] ET eustachian tube, GPN greater petrosal nerve, MCFd dura of the middle cranial fossa, MMA middle meningeal artery, SPS superior petrosal surface, TI trigeminal impression, V3 third branch of the trigeminal nerve, yellow arrow accessory middle meningeal artery, white asterisks greater petrosal nerve groove
  323. 323. Infrapetrous approach
  324. 324. Inferior petrosal sinus is superior to jugular tubercle & hypoglossal canal is inferior to jugular tubercle Infratemporal fossa [=intact cochlear approach – Dr.Morwani ] type B approach
  325. 325. The pontomedullary junction. 1. The exit zones of the hypoglossal and abducent nerves are at the same level [ same vertical line when view from Transclival approah ( through lower clivus ) ] 2. The abducent nerve exits from the pontomedullary junction, and ascends in a rostral and lateral direction toward the clivus.
  326. 326. In infrapetrous approach there are chances of injury to 6th nerve [ in dorello’s canal medial to paraclival carotid ] & 12th nerve
  327. 327. When we are drilling lower clivus – lateral to hypoglossal canal we get Jugular fossa
  328. 328. Adenoid cycstic carcinoma clivus -- Just look at the carotid. .The paraclival both sides 360 degree encased..look at the mass eroding Petros apex going above horizontal carotid above the meckels cave..we need a trans cavernous..trans supra Petros. .infra Petros. . App..
  329. 329. Sub frontal approach
  330. 330. Fig. 2.1 Drawing showing the skin incision (red line), the craniotomy and the microsurgical intraoperative view of the subfrontal unilateral approach. This approach provides a wide intracranial exposure of the frontal lobe and easy access to the optic nerves, the chiasm, the carotid arteries and the anterior communicating complex
  331. 331. Fig. 2.4 Intraoperative microsurgical photograph showing contralateral extension of the tumor (T) dissected via a unilateral subfrontal approach. Note on the left side the falx cerebri (F) and the mesial surface of the left frontal lobe (FL)
  332. 332. Fig. 2.5 Drawing showing the skin incision (red line), the craniotomy and the microsurgical anatomic view of the subfrontal bilateral route. This approach provides a wide symmetrical anterior cranial fossa exposure and easy access to the optic nerves, the chiasm, the carotid arteries and the anterior communicating arteries complex
  333. 333. Supraorbital approach - Fig. 3.2 Illustrations comparing the incision and bony exposure in a supraorbital craniotomy with those in a pterional craniotomy. a The supraorbital craniotomy utilizes the subfrontal corridor and involves a frontobasal burr hole and removal of a small window in the frontal bone. b The pterional craniotomy utilizes a frontotemporal incision and removal of the frontal and temporal bones andsphenoid wing. The pterional craniotomy primarily exploits the sylvian fissure
  334. 334. Frontotemporal approach
  335. 335. Fig. 4.6 a Craniotomy. b When the flap has been removed the lesser wing of the sphenoid is drilled down to optimize the most basal trajectory to the skull base. c Dural opening. DM dura mater, FL frontal lobe, MMA middle meningeal artery, LWSB lesser wing of the sphenoid bone, SF sylvian fissure, TL temporal lobe, TM temporal muscle, ZPFB zygomatic process of the frontal bone
  336. 336. Fig. 4.8 Intradural exposure; right approach. Before (a) and after (b) opening of the Sylvian fissure. A1 first segment of the anterior cerebral artery, AC anterior clinoid, FL frontal lobe, HA Heubner’s artery, I olfactory tract, III oculomotor nerve, ICA internal carotid artery, LT lamina terminalis, M1 first segment of the middle cerebral artery, MPAs perforating arteries, ON optic nerve, P2 second segment of the posterior cerebral artery, PC posterior clinoid, PcoA posterior communicating artery, SF sylvian fissure, TL temporal lobe, TS tuberculum sellae
  337. 337. Fig. 4.9 Intradural exposure; right approach. a Instruments enlarging the optocarotid area. b Displacing medially the posterior communicating artery, exposing the contents of the interpeduncular cistern. AC anterior clinoid, AchA anterior choroidal artery, BA basilar artery, FL frontal lobe, ICA internal carotid artery, III oculomotor nerve, OA left ophthalmic artery, ON optic nerve, OT optic tract, P2 second segment of the posterior cerebral artery, PC posterior clinoid, PcoA posterior communicating artery, Ps pituitary stalk, SCA superior cerebellar artery, SHA superior hypophyseal artery, TE tentorial edge, TL temporal lobe
  338. 338. Fig. 4.10 Intradural exposure; right approach; enlarged view. A1 first segment of the anterior cerebral artery, A2 second segment of the anterior cerebral artery, AC anterior clinoid, AcoA anterior communicating artery, BA basilar artery, FL frontal lobe, HA Heubner’s artery, ICA internal carotid artery, III oculomotor nerve, LT lamina terminalis, M1 first segment of the middle cerebral artery, OA left ophthalmic artery, ON optic nerve, P2 second segment of the posterior cerebral artery, PC posterior clinoid, PcoA posterior communicating artery, SCA superior cerebellar artery, SHA superior hypophyseal artery, TE tentorial edge, TL temporal lobe, TS tuberculum sellae
  339. 339. Fig. 4.11 Intradural exposure; right approach; close-up view ofthe interpeduncular fossa. AchA anterior choroidal artery, BAbasilar artery, DS dorsum sellae, III oculomotor nerve, IV trochlear nerve, P1 first segment of the posterior cerebral artery,P2 second segment of the posterior cerebral artery, PC posteriorclinoid, PcoA posterior communicating artery, Ps pituitary stalk, SCA superior cerebellar artery, TE tentorial edge
  340. 340. Endoscope-assisted microsurgery [ 45° endoscope in a corridor between the carotid artery and the oculomotor nerve ]-- Fig. 4.12 Intradural exposure; right approach; microsurgical (a) and endoscopic (b–d) views. AchA anterior choroidal artery, BA basilar artery, C clivus, FL frontal lobe, ICA internal carotid artery, III oculomotor nerve, ON optic nerve, P1 first segment of the posterior cerebral artery, P2 second segment of the posterior cerebral artery, PC posterior clinoid, PCA posterior cerebral artery, PcoA posterior communicating artery, SCA superior cerebellar artery, TE tentorial edge, TL temporal lobe, Tu thalamoperforating artery; green dotted triangle area for entry of the endoscope into the interpeduncular fossa
  341. 341. Fig. 4.12 Intradural exposure; right approach; microsurgical (a) and endoscopic (b–d) views. AchA anterior choroidal artery, BA basilar artery, C clivus, FL frontal lobe, ICA internal carotid artery, III oculomotor nerve, ON optic nerve, P1 first segment of the posterior cerebral artery, P2 second segment of the posterior cerebral artery, PC posterior clinoid, PCA posterior cerebral artery, PcoA posterior communicating artery, SCA superior cerebellar artery, TE tentorial edge, TL temporal lobe, Tu thalamoperforating artery; green dotted triangle area for entry of the endoscope into the interpeduncular fossa
  342. 342. Fig. 4.13 Intradural exposure; right approach; microsurgical (a) and endoscopic omolateral (b) and contralateral (c) views. A1 first segment of the anterior cerebral artery, AC anterior clinoid, ICA internal carotid artery, FL frontal lobe, III oculomotor nerve, LT lamina terminalis, M1 first segment of the middle cerebral artery, OA left ophthalmic artery, ON optic nerve, PcoA posterior communicating artery, SHA superior hypophyseal artery, TE tentorial edge, TS tuberculum sellae
  343. 343. Fig. 4.13 Intradural exposure; right approach; microsurgical (a) and endoscopic omolateral (b) and contralateral (c) views. A1 first segment of the anterior cerebral artery, AC anterior clinoid, ICA internal carotid artery, FL frontal lobe, III oculomotor nerve, LT lamina terminalis, M1 first segment of the middle cerebral artery, OA left ophthalmic artery, ON optic nerve, PcoA posterior communicating artery, SHA superior hypophyseal artery, TE tentorial edge, TS tuberculum sellae
  344. 344. Fronto-temporal orbitozygomatic transcavernous approach COM= Caratico-occulomotor membrane , DR = dural ring
  345. 345. Division of PComA
  346. 346. Fig. 4.15 Microsurgical view; extradural anterior clinoidectomy. a Exposure and drilling of the anterior clinoid process and optic canal under microscope magnification. b Widened space after complete removal of the AC. AC anterior clinoid, eON extracranial intracanalar optic nerve, FD frontal dura, ICA internal carotid artery, iON intraorbital optic nerve, LWSB lesser wing of sphenoid bone, OC optic canal, OR orbit roof, SOF superior orbital fissure, TD temporal dura
  347. 347. Fig. 4.16 Microsurgical view; intradural anterior clinoidectomy. a, b After the dura above the anterior clinoid process has been transected in a “T” shape (a), we usually drill always parallel tothe optic nerve and to the carotid artery (b). c The distal ring is finally exposed. A1 precommunicating anterior cerebral artery, AC anterior clinoid, AchA anterior choroid artery, Ch optic chiasm, DR distal ring, fl falciform ligament, FL frontal lobe, ICA internal carotid artery, M1 first tract of the middle cerebral artery, ON optic nerve, PC posterior clinoid, PCOA posterior communicating artery, TS tuberculum sellae
  348. 348. Fig. 4.16 Microsurgical view; intradural anterior clinoidectomy. a, b After the dura above the anterior clinoid process has been transected in a “T” shape (a), we usually drill always parallel tothe optic nerve and to the carotid artery (b). c The distal ring is finally exposed. A1 precommunicating anterior cerebral artery, AC anterior clinoid, AchA anterior choroid artery, Ch optic chiasm, DR distal ring, fl falciform ligament, FL frontal lobe, ICA internal carotid artery, M1 first tract of the middle cerebral artery, ON optic nerve, PC posterior clinoid, PCOA posterior communicating artery, TS tuberculum sellae
  349. 349. Posterior clinoidectomy
  350. 350. FTOZ – Fronto-temporal orbitozygomatic approach
  351. 351. FTOZ – Fronto-temporal orbitozygomatic approach
  352. 352. Subtemporal approach
  353. 353. Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura obtained through the pretemporal and subtemporal corridors. In this patient the basilar apex is well above the superior margin of the dorsum sellae. b Same patient. A more lateral exposure showing the pontomesencephalic junction surface and the neurovascular structures in the ambient cistern. c Intraoperative photograph of another patient showing structures in the left lateral incisural space from the subtemporal corridor. d Same patient. More lateral view. e Same patient. More posterior exposure. The lifting of the free edge of the tentorium shows the trochlear nerve entering the tentorium. The junction between the P2a and P2p segments (P2a, P2p) of the posterior cerebral artery is shown. ACA anterior cerebralartery, AChA anterior choroidal artery and tiny perforating vessels, BA basilar artery, DS dorsum sellae, FET free edge of tentorium, ICA internal carotid artery, LM Liliequist’s membrane, LON left optic nerve, ON oculomotor nerve, OT optic tract, PCA posterior cerebral artery, PComA posterior communicating artery, PLChA posterolateral choroidal artery arising from the P2a–P2p junction, PS pituitary stalk, RON right optic nerve, SCA superior cerebellar artery, TN trochlear nerve in the arachnoidal covering
  354. 354. Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura obtained through the pretemporal and subtemporal corridors. In this patient the basilar apex is well above the superior margin of the dorsum sellae. b Same patient. A more lateral exposure showing the pontomesencephalic junction surface and the neurovascular structures in the ambient cistern. c Intraoperative photograph of another patient showing structures in the left lateral incisural space from the subtemporal corridor. d Same patient. More lateral view. e Same patient. More posterior exposure. The lifting of the free edge of the tentorium shows the trochlear nerve entering the tentorium. The junction between the P2a and P2p segments (P2a, P2p) of the posterior cerebral artery is shown. ACA anterior cerebral artery, AChA anterior choroidal artery and tiny perforating vessels, BA basilar artery, DS dorsum sellae, FET free edge of tentorium, ICA internal carotid artery, LM Liliequist’s membrane, LON left optic nerve, ON oculomotor nerve, OT optic tract, PCA posterior cerebral artery, PComA posterior communicating artery, PLChA posterolateral choroidal artery arising from the P2a–P2p junction, PS pituitary stalk, RON right optic nerve, SCA superior cerebellar artery, TN trochlear nerve in the arachnoidal covering
  355. 355. Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura obtained through the pretemporal and subtemporal corridors. In this patient the basilar apex is well above the superior margin of the dorsum sellae. b Same patient. A more lateral exposure showing the pontomesencephalic junction surface and the neurovascular structures in the ambient cistern. c Intraoperative photograph of another patient showing structures in the left lateral incisural space from the subtemporal corridor. d Same patient. More lateral view. e Same patient. More posterior exposure. The lifting of the free edge of the tentorium shows the trochlear nerve entering the tentorium. The junction between the P2a and P2p segments (P2a, P2p) of the posterior cerebral artery is shown. ACA anterior cerebralartery, AChA anterior choroidal artery and tiny perforating vessels, BA basilar artery, DS dorsum sellae, FET free edge of tentorium, ICA internal carotid artery, LM Liliequist’s membrane, LON left optic nerve, ON oculomotor nerve, OT optic tract, PCA posterior cerebral artery, PComA posterior communicating artery, PLChA posterolateral choroidal artery arising from the P2a–P2p junction, PS pituitary stalk, RON right optic nerve, SCA superior cerebellar artery, TN trochlear nerve in the arachnoidal covering
  356. 356. THE FULLY ENDOSCOPIC SUBTEMPORAL APPROACH [ from Shahanian book ] - The traditional middle fossa subtemporal approach requires long- standing placement of retractors on the temporal lobe; therefore, potential injury to the temporal lobe can occur (e.g., hematoma and edema resulting in aphasia, hemiparesis, or seizures). This concern should not be a problem with the described approach because temporal lobe retractors are not used. (L) a Epidermoid tumor. b Atraumatic suction. c Brainstem. d Occulomotor (III) nerve. e Posterior cerebral artery (PCA). f Superior cerebellar artery (SCA). g Trochlear (IV) nerve. (N) a Epidermoid tumor. b Atraumatic suction. c Left-curved tumor forceps. d Occulomotor (III) nerve. e Posterior cerebral artery (PCA). f Posterior communicating (PCOM) artery. g Superior cerebellar artery (SCA). h Brainstem. i Trochlear (IV) nerve.
  357. 357. Q) a Occulomotor (III) nerve. b Internal carotid artery (ICA). c Posterior cerebral artery (PCA). d Superior cerebellar artery (SCA). (P) a Ipsilateral optic (II) nerve. b Internal carotid artery (ICA). c Occulomotor (III) nerve. d Dura overlying anterior clinoid process.
  358. 358. Carotid artery bleeding
  359. 359. SKULL BASE 360° Above presentation is SKULL BASE 360°-Part 1 For SKULL BASE 360°-Part 2 Please click or copy/paste in URL or weblink area http://www.slideshare.net/muralichandnallamoth u/edit_my_uploads [ Dated: 19-4-14 ] I will update continuosly with date tag at the end as I am getting more & more information

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