The document discusses different types of skull base surgical approaches - Type A, B, and C. Type A involves radical mastoidectomy and exposes the jugular bulb, carotid artery, and posterior fossa. Type B explores the petrous apex, clivus, and superior infratemporal fossa. Type C allows exposure of structures like the nasopharynx and parasellar area. The infratemporal fossa approach has allowed advances in lateral skull base surgery for tumors like glomus jugular tumors.

1. Dr Zeeshan Ahmad
M.S.(ENT, PGY3)
Department of ENT, NMCH,
Patna.26.03.2015

3.  Head of the ENT Department of the University
Hospital in Zurich from 1970 to 1999.
 At present he is in charge of Otology and Skull
Base Surgery at the ORL-Center of the Klinik
Hirslanden, Zurich.
 Published more than 300 articles concerning
Microsurgery of the Middle Ear and the Skull
Base.
 He is also author of many books. Two of them,
"Tympanoplasty, Mastoidectomy and Stapes
Surgery" and "Microsurgery of the Skull Base"
are classics in the ENT field.

4.  TYPE A
 TYPE B
 TYPE C

5.  Type A dissection entails radical
mastoidectomy, anterior transposition of
the facial nerve, exploration of the
posterior infratemporal fossa, and cervical
dissection permitting access to the
 jugular bulb,
 vertical petrous carotid, and
 posterior infratemporal fossa.

6.  Type B dissection explores the
 petrous apex,
 clivus, and
 superior infratemporal fossa.

7.  Type C allows exposure of
 the nasopharynx,
 peritubal space,
 rostral clivus,
 parasellar area,
 pterygopalatine fossa, and
 anterosuperior infratemporal fossa.

9.  Should allow for further extension
 Vascularization
 Cervical exposure
 Anterior extension
 Periosteal flap
 EAC transection

11.  Undermined
 Everted
 Sutured
 Reinforced
with
periosteal flap

12.  Skin elevated circumferentially
 Annulus lifted
 incudostapedial joint is separated
 Tensor tympani tendon is cut
 Neck of the malleus is nipped

14.  Expose the inferior margins of the tumor
 Control of vessels
 Greater auricular nerve sectioned carefully
 Neurovascular structures identified
 Posterior belly of Digastric cut

15.  located deep to the midpoint of a line
between the tragal pointer cartilage and
the mastoid tip
 In the type B and type C approaches, facial
nerve transposition is not required; only the
frontal branch is followed distally to allow
its preservation when the zygoma is
transected.

17.  Removal of air cell tracts lateral and
adjacent to the otic capsule
 Cavity obliteration
 Facial nerve skeletonization
 Stapes suprastructure removal
 Eustachian tube obliteration

19.  Skeletonize
 from the geniculate ganglion to the
stylomastoid foramen
 LSCC
 Digastric ridge
 Stylomastoid foramen
 new bony canal is drilled in the anterior
wall of the epitympanum to receive the
nerve

21.  Posterior fossa dura anterior and posterior
to the sigmoid sinus
 Dura is elevated with dural hooks
 incised in front and behind the sigmoid sinus
 a blunt-tipped aneurysm needle - ligature
 CSF leak managed
 Alternatively, intraluminal absorbable
packing

23.  Styloid process is fractured and removed
 Parotid dissected off the tympanic bone
 Laminectomy retractor for mandible
 Facial nerve monitoring
 With removal of bone over the carotid
artery and beneath the otic capsule, the
jugular fossa is exposed for tumor removal

25.  After exposure and distal control of the
internal carotid artery are accomplished,
the tumor may be carefully removed.
 The jugular vein is ligated to prevent tumor
and air embolism
 Dissection begins by freeing the internal
carotid artery and rotating the tumor
posteriorly

26.  The lateral wall of the sigmoid sinus is
removed along with intraluminal tumor
 extracranial tumor is removed
 If the tumor extends intracranially, it is
amputated sharply at this point
 posterior fossa dura is opened, and the
intracranial portion of the tumor is excised
 same setting for intracranial tumors smaller
than 2 cm

29.  The dura usually is left with a defect too
large for primary closure - Fascia lata
 Abdominal fat - obliterate the dead space of
the temporal bone
 Temporalis muscle - rotated inferiorly for
reinforcement of the wound
 The skin is closed routinely

32.  The steps up to transposition are identical
to those for the type A approach
 transposition of the nerve usually is not
required.
 Reflection of the temporalis muscle still
attached to the coronoid process and the
zygoma allows the retractor to expose the
superior infratemporal fossa

34.  The middle meningeal artery - bipolar
cauterization
 V3 – transection
 The carotid artery may be uncovered from
its vertical segment to its anterior limit at
the foramen lacerum after separation from
the soft tissues around the eustachian tube

36.  Petrous apex lesions, such as
 cholesteatoma or
 low-grade chondrosarcomas,
 removed with careful anterolateral retraction
of the internal carotid artery.
 Extensive benign lesions
 petrous apex and perilabyrinthine area
 require a transotic approach combined with
posterior facial nerve transposition

37.  Exposure of the clivus
 obtained by sharp incision of the fibrous
attachments at the petro-occipital fissure.
 Tumors of the clivus, such as chordomas, up
to the parasellar area may be removed
through the type B approach
 Removal of the mandibular condyle may
give better exposure to the inferior clivus
and upper cervical vertebrae

39.  Anterior extension of type B
 Permits posterolateral access to the
 rostral clivus,
 cavernous sinus,
 sphenoid sinus,
 peritubal space,
 pterygopalatine fossa, and
 nasopharynx and
 to the areas exposed by the type B
approach

40.  The base of the pterygoid process is
removed to approach the sphenoid sinus and
cavernous sinus
 Removal of the pterygoid base uncovers V2
in the foramen rotundum and the inferior
orbital fissure.
 The cavernous sinus is exposed by thinning
the bone of the middle cranial fossa floor
anterior to the V2 stump.

42.  To enter the lateral nasopharyngeal cavity,
the lateral and medial pterygoid processes
are removed, and the buccopharyngeal
fascia and nasopharyngeal mucosa are
incised.
 Separation of the pterygoid muscles from
the mandible allows en bloc removal of the
lateral nasopharyngeal wall, peritubal
space, and superior infratemporal contents
when needed for tumor extirpation

44.  The infratemporal fossa approach, in
conjunction with the application of
microsurgical technique and improved
perioperative care, has permitted
significant advances in lateral skull base
surgery.
 The glomus jugular tumor is the
prototypical neoplasm resected by this
approach, although this technique can be
applied to a host of additional benign and
malignant lesions of the skull base.

46. 02.04.15 Dr Sonu Kr
Singh
M.S.(ENT,PGY3)
Cochlear Implantation –
Candidacy and
Postoperative
rehabilitation