40
We routinely use graphic diagrams of the anat-
omy and provide pamphlets to our patients to
take home. Patients who are candidates for hear-
ing preservation surgery are informed that there
is an approximately 50% chance that their hear-
ing will be “saved”; however it is unlikely that it
will improve after tumor removal [ 36 ]. It is reiter-
ated in those undergoing the translabyrinthine
approach that the operation will result in com-
plete loss of hearing in the operative ear. The
patient is counseled that with the middle fossa
approach, there is approximately a 90% chance
that the facial nerve function will be normal or
near normal (House-Brackmann grade I or II) in
the long term. They are informed that there is,
however, a 20–30% chance of having temporary
facial paresis in the immediate to early postoper-
ative period. Those undergoing a translabyrin-
thine approach are told that the facial nerve
integrity is preserved in 90% of patients, and our
best and most consistent results are seen with
smaller tumors removed via the translabyrinthine
approach. As the tumor size increases, the rate of
postoperative facial nerve dysfunction increases
as well. Those with preoperative tinnitus are told
that while their symptoms may get better, it is
unlikely to disappear. It is divulged to those with
no preoperative tinnitus that there is a 25%
chance of developing it postoperatively [ 37 ]. The
rare but serious complications of CSF leak, men-
ingitis, brain injury, stroke, and death are dis-
cussed, and the patient’s wishes regarding
possible blood transfusion are documented. The
expected recovery, including 4–6 weeks of down-
time from work, is outlined. We stress that dizzi-
ness is expected postoperatively, and that the
rapidity and degree of central compensation is
influenced greatly by early patient ambulation.
Surgery
General Preoperative Preparation
Long acting muscle relaxants are avoided at
induction and throughout the procedure to pre-
vent interference with facial nerve monitoring. A
Foley catheter is placed to monitor urine output,
and central arterial and venous lines are inserted,
if indicated. A preoperative antibiotic with ade-
quate CSF penetration is given prior to skin inci-
sion, and a single dose of intravenous
dexamethasone is given at the beginning of the
procedure. The patient’s head is supported by a
“donut” or a Mayfield head holder and is rotated
toward the contralateral shoulder. For middle
fossa craniotomies, the head can be secured with
pins or simply turned to the side contralateral to
the tumor. The electrodes for the facial nerve
monitor and intraoperative ABR, when hearing is
monitored in middle fossa approaches, are posi-
tioned and confirmed to be functioning. The pre-
planned surgical incisions are injected with 1%
lidocaine with epinephrine 1:100,000. If abdomi-
nal fat is to be harvested, the lower abdomen is
shaved if necessary, the skin is cleaned with
Betadine, and the area is draped with sterile tow-
els and Ioban.Surgical Technique: Middle Fossa
Approach
For the middle fossa craniotomy, the surgeon sits
at the head of the table, and the microscope is off
to the side. The ipsilateral scalp is shaved to
accommodate the incision, which begins at the
pretragal area and extends superiorly 7–8 cm
with a gentle curve anteriorly (Fig. 3.1). The inci-
sion should begin at the inferior border of the tra-
gus and be immediately anterior to the tragus,
placed in a pretragal skin crease. The pretragal
skin crease placement minimizes the cosmetic
impact of this facial incision. By extending the
incision to the inferior border of the tragus, one
can expose the floor of the middle fossa more
easily. Plastic adhesive drapes are applied; the
skin and plastic drapes are scrubbed with
Betadine and blotted dry. Towels are placed
encompassing the temporoparietal scalp, includ-
ing the auricle and zygomatic arch. An adhesive
craniotomy drape is placed and cut away to
expose the skin prior to making the skin incision.
Intraoperative mannitol is given to decrease intra-
cranial CSF pressure and to facilitate temporal
lobe retraction. The skin incision is made with a
No. 15 blade, and the temporalis muscle and fas-
cia are divided with electrocautery and retractedJ.C. Sowder et al.