2. Refrences
Schmidk and Sweets operative techniques
Youmans 7th editions
Neurosurgical concepts and approaches to orbital tumor,
article in advances and technical standards in
neurosurgery Vol 31, 2006.
3. Introduction
Shape---4 sided pyramid with its axis set off from the
sagittal plane by an angle of 20 degree.
Approx vol 30 cm3
Seven bones: frontal, zygomatic, sphenoid, lacrimal,
ethmoid, palatine bones and maxilla
4.
5. Borders of the orbit
Lateral border:
Superiorly by the
zygomatic process of
the frontal bone.
Inferiorly by the frontal
process of the
zygomatic Bone
Inferior border
laterally by zygoma
medially by the maxilla
6. Medial border
Upper part by frontal bone
lower part by frontal process
of the maxilla.
Upper border by the frontal
bone,
-supraorbital foramina
- supraorbital &
supratrochlear nerves and
vessels.
7. Orbital roof from below
Anteriorly by orbital plate of F’
bone
Posteriorly by lesser wing of
sphenoid bone.
Lacrimal fossa - depression in
the antero-lateral part of the
roof for Lacrimal gland
Trochlear fossa – Depression on
the anteromedial part of the
roof, serves as attachment
for the trochlea of SO.
8. Orbital roof from above
The sphenoid and ethmoid bones
are interposed between the orbital
roofs
In ethmoid bone, the cribriform
plate and upward projecting crista
galli, to which falx attaches
Anteriorly frontal bones split into
two laminae, which enclosed the
frontal sinuses
9. Orbital floor
Formed by
1 orbital plate of the maxilla,
2 orbital surface of the zygoma,
3 orbital process of the palatine
bone.
1. medial wall, nasolacrimal
canal.
2. lateral wall, except posteriorly
where they are separated by the
inferior orbital fissure.
3. Traversed by infraorbital
groove, made canal for
Maxillary n.
10. Superior orbital fissure
Above by lesser wing of
sphenoid bone, ACP and
optic strut
Below by the junction of
greater wing with the
sphenoid body
Medially by the lateral surface
of optic strut and sphenoid
body
11. Inferior orbital fissure
Long posterior edge by the
greater wing of sphenoid.
Long anterior wall by the
orbital surface of the maxilla
and the orbital process of the
palatine bone.
12. Orbital aspect of the right inferior orbital
fissure
Narrow lateral end by the Z’ bone.
Narrow medial end by the
sphenoid body.
The posteromedial part of the
fissure communicates below
with the pterygopal fossa and
anterolateral part communicates
with the infra-T’ fossa.
13. Orbital content
Two parts
Anterior: eye ball
Posterior: muscle, vessels, nerves, cellular and fatty matrix.
Eye ball 6 mm outside and 11 mm inside.
From ON upto the sclero-corneal junction, eyeball is covered
by a two-layer fascia (Tenon’s capsule) with parietal and
visceral sheets separating it from the orbital fatty tissue.
14. Orbital muscle
LPS: Triangular, originates from orbital surf of Sphenoid,
anterosuperior to OC.
It terminates in an anterior tendon that spreads out in the form
of a large fascia, which extends out to the eyelid.
The edges of this fascia form extensions, laterally traverses
the lacrimal gland orbital parts and goes on to attach to the
fronto-zygomatic suture.
15.
16. Rectus muscles: From CAT (Zinn’s
Tendon) located in the body of
Spenoid near the infraorbiral
tubercle..
Devides into 4 lamallae.
The superolateral and inferomedial
ligaments are solid but the other
two are perforated:
Superomedial band : O.N. and O.A.
This opening called the common
tendinous ring (Zinn’s ring)
17. Annular tendon
At the junction b/w the 2 part (inferomedial bulge and
superolateral taper) of SOF small bony protuberance on the
lower lip to which common tendinous ring is attached.
Attached to the upper, lower, and medial margin of the optic
canal.
The lateral edge of the annular tendon is attached to the
mid-portion of the lateral edge of SOF.
.
18. Annular tendon
3 sectors:
Lateral sector –transmits the IV, frontal (medial) and lacrimal
nerves(lateral) and supr opht vein
Central sector (Occulomotor foramen) – transmits the III,
nasociliary and VI nerves and sensory and sympathetic
root of ciliary ganglion
Inferior sector – transmits infr opht vein
19.
20.
21. Superior rectus
Origin:- Common
annular tendon.
Insertion:- at sclera
posterior to the margin
of cornea (slightly
oblique and curved)
IIIrd nerve superior
division
Upward, medial rotation,
intortion
22. Inferior rectus
Origin:- Common annular
tendon
Insertion:- obliquely
attached with medial side
slightly anterior to the
lateral end
IIIrd nerve inferior division
Down, medial rotation and
extortion.
23. Medial rectus
Origin:- Common annular
tendon
Insertion:- vertical line of
attachment to the sclera
III nerve inferior division
Medial rotation.
24. Lateral rectus
Origin:- Segment of annular
tendon passing from greater
to lesser
Insertion:- vertical line of
attachment to the sclera
posterior to the margin of
cornea
VIth cranial nerve
Lateral rotation.
25.
26. Superior oblique
Origin:- periorbita of body
of sphenoid superomedial
to optic canal.
Insertion:- sclera, behind
the equator of eye b/w SR
and LR (after passing
through the trochlea)
IVth cranial nerve.
Down, lateral rotation and
intortion.
27. Inferior oblique
Origin:-orbital surface of
maxilla, lateral to
nasolacrimal duct (Not
from the apex).
Insertion:-little below and
posterior to superior
oblique.
IIIrd cranial nerve.
Upward, lateral rotation,
and extortion.
28. Optic canal
Medial margin by the
sphenoid body.
Upper margin by the anterior
root of the lesser sphenoid
wing.
Lateral margin by the optic
strut (posterior root of the
lesser wing).
Lower margin by the optic
strut and the adjacent part of
the sphenoid body.
29. Optic canal
5-10 mm x 4.5 mm x 5 mm
Optic strut: forms the
inferior–lateral border of
canal and separates it from
SOF.
The proximal, dorsal opening
is a fold of dura called the
falciform ligament.
30.
31. Optic Nerve
2. Intraorbital – surrounded by the orbital fat and follows a slight
tortuous course (30mm), SO, MR, SR.
3. Intracanalicular – optic canal, forms a prominence in the upper
part of sphenoid sinus immediately in front of the sella
turcica (5mm)
4. Intracranial – directed posteriorly, superiorly and medially
toward the optic chiasm (10mm)
32. Optic Nerve
4 cm lenght, 3 mm dia, Four parts:
1. Intraocular – includes the optic disc, lies within the sclera
33. 2. Intraorbital – 30 mm, – the muscles of the orbit, fatty tissue,
then coming closer nearer the point of entry of the optic canal
where the nervous sheath is attached to the tendinous fibers of
the SO, MR, SR, and O.A. (crosses over the nerve)
34. 3. Intracanalicular -
(5mm), with O.A. just in
front of the canal, OA
and NCN carry on
medially and in a
forward direction above
the ON,
The nerve supplying the
MR, passes below ON in
a medial direction.
35. 4. Intracranial – directed posteriorly, superiorly and
medially toward the optic chiasm (10mm),
36. Oculomotor
SOF, the NCN is located between them on the inside
with VI n. on the outside. Enter to cone and diverge.
1) Superior division, lateral side of ON, and splits to
form 4-5 rami to SR and LPS.
2) Inferior division initially located below and outside
the ON, then spread over the upper surface of IR,
splitting to form 3 br.
37. 1st Below ON, MR.
2nd Outside towards IR
3rd (the longest), carries on
in front b/w IR and LR,
oblique muscle.
38.
39. Trochlear
Courses in the lateral wall
of the CS below the III N.
and above the Opth n.
It passes through the SOF,
outside the annular tendon
and passes medially above
F’ n. and the LPS, reaches
the SO.
40. Abducen Nerve
Travels in CS on medial
side of the opth n.
Laterally below the
NCN as it passes
through the SOF and
annular tendon.
Enter the medial surface
of the lateral rectus
muscle.
41. Ophthalmic Artery
Arises ant just above the
CS medial to ACP, from
the supraclinoid part of
ICA.
In canal, Inferolateral
In orbit, lateral to medial
along NCN b/w SO &
MR.
42. Supratrochlear and
dorsonasal br.
The central retinal art
also assumes a medial
course as it supplies the
nerve.
Lacrimal art.
Muscular br.
Ciliary art.
Supraorbital art.
43. Venous system
Supr Opth vein: arises from tributaries in the superomedial
part of the orbit – passes backward on the lateral side of SO
and crosses the ON to reach the lateral side
Inf Opth vein arises from tributaries in the inferolateral part
of the orbit – courses medially and posteriorly and exit the
muscle cone between LR & IR.
44. IOVein communicates with
the pterygoid venous plexus
through the IOF
Both join to form the common
stem that drains into antero-
inferior part of the cavernous
sinus
45. SUPERIOR VIEW OF A STEPWISE
DISSECTION OF
THE NEURAL STRUCTURES IN THE
ORBIT AND
SUPERIOR ORBITAL FISSURE.
46. The dura has been
removed from the part of
the frontal and sphenoid
bones forming the
orbital roof.
47. The periorbita opened to
expose the Lacrimal
Frontal, Trochlear, nerves
coursing in the orbital fat
just beneath the periorbita.
48. frontal nerve, levator and
superior rectus muscles
divided and reflected.
This exposes the Superior
ophthalmic vein, OA, and
nasociliary nerve as they
pass above the O.N.
49. Spaces of the Retrobulbar Orbit
•Extraconal space:
–Contains ophthalmic vein, lacrimal nerve (V1), CN IV
and frontal nerve (V1).
•Intraconal space:
–Contains CN II, ophthalmic artery, superior division of
CN III, inferior division of CN III, NCN, (V1), and CN
VI.
51. Classification on basis of Origin
1. Primary lesions, from the orbit itself.
2. Secondary lesions, which extend to the orbit from
neighbouring structures and include such lesions
as intracranial tumors and tumors of the paranasal
sinuses that, by contiguity, involve the orbit.
3. Metastatic tumors, lesions reach the orbit via
hematogenous or lymphatic spread.
52. Surgical Approaches (“Around the Clock”)
Intraconal, extraconal and intracanalicular
Transorbital and extraorbital
Extraorbital: Extended Bifrontal C, Orbitozygomatic C,
Subcranial C, and U/L Maxillectomy
Ant lesions--via transorbital approaches
Post 3rd of the orbit---extraorbital approaches.
53. The lateral microsurgical approach ---8 to 10 o'clock
F’T’ craniotomy w orbital osteotomy---9 to 1 o'clock.
Addition of a zygomatic osteotomy---6 to 8 o'clock.
The medial micro-orbitotomy---------1 to 5 o'clock.(ANT)
The endoscopic endonasal------------1 to 7 o'clock.(POST)
54. Surgical approaches to orbit
Divided into 2 groups :
A) Extracranial approach :
Lateral orbitotomy
Transethmoidal orbitotomy
Frontal trans-sinusoidal
Transmaxillary
Transconjuctival
B) Transcranial approach :
Subfrontal
Fronto-lateral pterional
Pterional extradural/Intradural
Petrional contralateral
55. Subfrontal
Indications: Intraorbital optic nerve glioma, growing into
cranial cavity, lateral tumors of optic nerve
Advantages: Good general exposure
Disadvantages: Traumatizing approach, requiring brain
retraction
56. Fronto-lateral pterional
Indications: Ideal approach for tumors of SOF, OC, orbital
apex, and intraorbital optic nerve; tumors located dorsal to ON
and lateral extra- and intraconal tumors
Advantages: Broad exposure, minimal brain retraction, good
access to extra- and intradural and intraorbital compartments
Disadvantages: No disadvantages
57. Pterional Extradural
Indications: Ideal for decompression of ON in OC, suitable for
periorbital tumors and for tumors near SOF & IOF, CS.
Advantages: Well tolerated, no brain retraction, clear exposure
Disadvantages: Detailed anatomic knowledge is essential
58. Pterional-contralateral
Indications: Tumors of medial orbital apex, aneurysms of
OA
Advantages: Direct approach to medial processes medial
and below ON
Disadvantages: Difficult without navigation, injury to
olfactorian nerves is possible, may involve extensive brain
retraction.
59. Lateral orbitotomy
Indications: Intra- and extra-conal tumors, lateral and basal to
optic nerve; orbital apex, retrobulbar, lacrimal gland tumors
Advantages: Good exposure, well-tolerated procedure
Disadvantages: Visible but minimal scar
60. TRANSCONJUNCTIVAL ANT MEDIAL
MICRO-ORBITOTOMYAPPROACHES
Indications: Restricted to basal and
medial intra- and extraconal tumors.
Advantages: Minimally invasive,
excellent cosmetic result. Large mass,
without bone destruction and scars, all
can be removed.
Disadvantages: Inability to deal with
deep intraconal lesions and lesions of
apex, Hypestheisa for 8 months.
61. Combined
Supraorbital via eyebrow incision
Indications: Well-circumscribed intra- and extra-conal
processes above optic nerve
Advantages: Minimally invasive extradural approach with
minimal manipulation of orbital structures and brain, no
limitation by size, excellent cosmetic result
Disadvantages: Hypesthesia for 8 months (supraorbital nerve)
62. ENDOSCOPIC ENDONASAL
APPROACHE
For intraconal and extraconal tumors that are medial and
inferior to ON and can be applied to any medial intracranial
extension, provided that neurovascular structures (e.g., the
optic nerve and ICA) remain lateral to the tumor.
In addition, EEAs provide access to most of the orbit, from the
posterior globe to the orbital apex.
63. POINTS TO REMEMBER
The intraorbital must not be damaged (the risk of
postoperative enophthalmos).
The lacrimal gland is easy to locate because of its relatively
firm texture and pinkish color.
The frontal nerve is very easily identified in the post half since
it is located immediately below the periorbita,
It passes immediately over the levator palpebrae muscle.
64. The central artery of the retina enters into the dura mater on
the nerve’s medial side at a distance of 8–15 mm behind the
eyeball.
All the branches of III n (except to IO) have fairly short paths
between the tendinous ring and their respective muscles
(junction of the posterior third and the middle third).
They can be damaged individually during surgery to remove
lesions at the apex or in the posterior third of the cone.
65. Complications
PTOSIS: levator muscle & / or its nerve damage
DIPLOPIA: EOM damage, ocular motor nerve damage, adhesions of
EOM, trochlea damage
VISUAL LOSS: CRA trauma / occlusion, globe compression, optic nerve
trauma / compression (H’age, edema)
CSF LEAK: inadvertent opening of the paranasal sinuses (post ethmoid )
while optic canal deroofing.
EYELID MALPOSITION: faulty wound closure, adhesions b/w lids &
orbital rim
PUPIL & ACCOMODATION ABNORMALITIES: Posterior ciliary N &
vessels damage
66. •FRONTAL BRANCH OF FACIAL N INJURY: Incision
>4cm from the lateral canthal margin in lateral orbitotomy
•OCULAR OR FACIAL SENSORY LOSS: sensory nerve
damage (nasociliary N, 1st/2nddivision of trigeminal N)
•CORNEAL ULCERATION: direct corneal trauma, corneal
dessication
68. The intracranial dura enters the canal as a combined dural-
periosteal layer before splitting into the dura of the optic nerve
(optic nerve sheath).
The intracranial arachnoid is separate through the optic canal,
but fuses with the pia at the globe.
At the orbital portion of the optic canal, the pia and arachnoid
are joined together dorsomedially and fuse to the dura and
anulus of Zinn ventrally.
69. Kronlein in 1889 for a large orbital & T’ fossa dermoid cyst.
Retrobulbar lesions, extended for more posterior lesions.
Temporary removal of the lateral wall of the orbit, access to
the entire lacrimal gland and lateral, superolateral, and
inferolateral tumors.
70. Incision: runs along the
lid crease towards the
corner of the eye to the
lateral canthus or even
lateral to it .
T’ fascia is incised,
beginning at the mid
portion of the F-Z bone
and extending posteriorly.
71. A saw is used to incise the lateral
rim of the orbit above the
zygomatico-frontal suture line an
inferiorly at the superior margin of
the zygomatic arch.
The anterior edge of the greater
wing of the sphenoid bone may be
further reduced with rongeurs .
72. The lateral orbit can be approached between the superior and
lateral rectus muscles.
Frontozygomatic bone is closed using plate and screw fixation.
