Skull Base Surgery of the Posterior Fossa

161

ment plan for postoperative complication avoid-
ance and vestibular function rehabilitation.

Conclusion

Detailed anatomical understanding of the middle
fossa, inner ear, and IAC anatomy is the key to
achieving the desired outcome with very low mor-
bidity and mortalities in the retrosigmoid, MFA,
and translabyrinthine approaches for VS resec-

tion. Unlike otolaryngologists, many neurosur-

geons are not familiar with these approaches

because of the rarity of VSs compared with the

other pathological processes that may involve the

inner or middle ear. Nevertheless, learning the

technical nuances of these approaches is advanta-

geous. Having dedicated skull base and ear, nose,

and throat surgical teams during the preoperative,

operative, and postoperative care for patients with

VSs treated using these approaches is an impor-

tant aspect for management of this pathology.

Fig. 11.8 Translabyrinthine approach for a large VS. (a,
b) Surgical position and skin incision marking. (c)
Completed bone removal of the mastoid air cells and
exposure of the presigmoid dura and the tumor in the right
IAC. Note the complete skeletonization of the sigmoid
sinus with only a thin shell of the bone left over the jugu-
lar bulb. (d) Identification of the Bell’s bar and opening
the IAC dura just posterior to it. Note the eustachian tube
plugged with muscle. (e) Further dissection of the tumor
off the facial nerve in the IAC. (f) Opening of the presig-
moid dura parallel and inferior to the sinodural angle. The
black lines denote the dural opening Fig. 11.8 (contin-
ued) around the IAC. (g) Debulking of the tumor after
opening a window in the backside of the tumor (facial
nerve stimulator is used to confirm the absence of aberrant

facial nerve course along the incision line of the tumor

capsule). (h) Lifting the tumor capsule off the cerebellum

and brainstem after adequate tumor debulking is achieved.

Note the use of cottonoids to gently dissect the tumor cap-

sule from the brainstem using traction-countertraction

technique in medial-to-lateral direction. (i) Identifying the

facial nerve at the inferior and anterior part of the tumor.

(j) Tumor remnant dissected from lateral-to-medial direc-

tion off the facial nerve after more tumor debulking. (k)

Complete tumor removal with intact facial nerve. Note the

view provided by translabyrinthine approach at the end of

the dissection (ability to see the whole length of the facial

nerve from the root exit zone to the IAC fundus). (l) The

use of an absorbable plate for mastoidectomy repair after

placement of fat graft over the presigmoid dura

11 Vestibular Schwannomas