Skull Base Surgery of the Posterior Fossa

95

long surgical access route to the tumor, and work-
ing in a narrow operative corridor between the
optic apparatus, oculomotor nerves, and carotid
vessels. Detailed description of these anterior/
anterolateral approaches is beyond the scope of
this chapter.
Lateral/posterolateral approaches include the
transpetrosal and suboccipital approaches [ 1 , 3 ,
4 , 11 ]. Transpetrosal approaches are the work-
horse for accessing PC tumors. They include
anterior, posterior, and combined transpetrosal
approaches, which are the primary focus of this
chapter. The primary advantages of transpetrosal
approaches over anterior/anterolateral approaches
are wider, shorter, and direct access to the tumor
and a much better surgical trajectory to access
tumors extending across the midline along ven-
tral brainstem. Limitations include the higher
risk for retraction injury to the temporal lobe with
consequent seizures and dysphasia, facial weak-
ness, hearing loss, cerebrospinal fluid rhinorrhea,
and iatrogenic injury to sigmoid sinus, transverse
sinus, and vein of Labbé leading to venous

infarcts. The decision to use either of these

approaches is governed by tumor size and extent,

preoperative hearing status, and surgeon’s prefer-

ence [ 1 , 3 , 4 , 11 ]. The retrosigmoid suboccipital

approach (Fig. 7.1) is yet another option to resect

lesions in PC region, although it is limited by the

supratentorial extension of the tumor and contra-

lateral extension across the ventral aspect of

brainstem. The interposition of facial and

cochlear cranial nerves between the tumor and

the surgeon further limits the surgical freedom.

The retrosigmoid suboccipital approach may also

be used as a second-stage procedure after an

anterior transpetrosal approach to resect the

residual tumor lateral to the internal acoustic

meatus and along the ventral brainstem. By

choosing this surgical strategy, many neurosur-

geons have been able to reduce the rate of iatro-

genic complications arising from much more

extensive combined (anterior and posterior)

transpetrosal approaches (see below). Far/

extreme lateral approaches can also be combined

with retrosigmoid suboccipital approaches for

Fig. 7.2 Illustration demonstrating various transfacial and transcranial skull base approaches to the clivus and petro-
clival regions (Reproduced with permission from Liu and Couldwell [ 32 ])

7 Petroclival Meningiomas