159tion. As the tumor is dissected, the redundant
capsule can be debulked more with microscissors
or an ultrasonic aspirator. This is continued until
just before the porus acusticus, where the maxi-
mum adhesion between the tumor and the facial
nerve usually exists. The dissection now is
directed toward the lateral extent of the tumor in
the IAC. The tumor is debulked similarly at the
lateral end of the IAC and then dissected sharply
off the facial nerve in a lateral-to-medial fashion.
A back-and-forth dissection–debulking tech-
nique is used to remove this last piece of tumor
from the facial nerve until both dissection plans
are met at the porus acusticus. All opened air
cells must be checked and sealed with bone wax.
Similar to the MFA, the closure is done using just
enough pieces of fat to fill the surgical corridor in
the mastoid. It is important to ensure that these
fat grafts do not fall into the intradural space in
the CPA angle. On the other hand, too much fat
packing may compress the sigmoid sinus and
should be avoided. The first fat piece may be
made just big enough to plug the dural opening,
and the other small fat pieces are placed over it. A
small absorbable plate is placed over the mastoid
to buttress the fat. The muscle and galea are
closed in layers; the skin is closed using a simple
running or locking nylon stitches (Fig. 11.8). The
extent of the bone removal and tumor removal
using the translabyrinthine approach can be seen
in Fig. 11.9.
Surgical Risks and Complications
The operative-related mortality rate for the trans-
labyrinthine approach for VS resection ranges
from 1% to 1.3% [ 1 , 31 ], mainly in elderly
patients with tumors larger than 3 cm [ 31 ]. CSF
leak postoperatively has been reported to occur in
1.8–14% of patients [ 28 , 31 ]. Major neurological
deficits such as stroke, seizure disorder, and per-
sistent cerebellar dysfunction have been reported
in 2.6% of patients [ 1 ]. In a large series of 1244
patients with VS who underwent translabyrin-
thine approach, the risk of the following compli-
cations was <1%: subdural hemorrhage, CPA
hematoma, cerebellar edema, brainstem hema-
toma, transient aphasia, and lower cranial nerve
dysfunction [ 31 ]. In cases where gross-total
resection was planned, residual tumor was
reported in 5.6% of patients [ 1 ].Facial Nerve Preservation
with the Translabyrinthine ApproachThe overall facial nerve preservation rate reported
with the translabyrinthine approach was 89.5% in
a large systematic review [ 1 ]. The reported rates
of facial nerve preservation are 100%, 84.2%,
and 57.7% for intracanalicular tumors, tumors
measuring 1.5–3 cm, and tumors larger than
3 cm, respectively [ 1 ].Limitations of Translabyrinthine
ApproachThe translabyrinthine approach is usually indi-
cated for resection of VS in patients with unser-
viceable hearing or with poor hearing preservation
prognosis preoperatively. The size of the tumor is
not a limiting factor for this approach; however,
in some cases, the jugular bulb is located very
close to the IAC, and careful studying of the jug-
ular bulb height in the preoperative MRI and CT
scans is important to ensure adequate distance
between the IAC and jugular bulb, especially in
large VSs.Specific Perioperative ConsiderationsThin-cut axial, sagittal, and coronal MRIs of the
skull base should be studied preoperatively. The
dominant temporal lobe and vein of Labbé must
be kept in mind for complication avoidance.
Neuronavigation systems that use stereotactic CT
scan or MRI may be useful surgical adjuncts to
localize the IAC and define the limits of bony
drilling. Facial nerve monitoring and BAER are
used routinely for all VS cases. Muscle paralysis
agents should be avoided during anesthesia.
Dexamethasone and mannitol can be used to
relax the brain and prevent dural tear during bone
elevation. Early mobilization and physiotherapy
postoperatively are important parts of the treat-11 Vestibular Schwannomas