Skull Base Surgery of the Posterior Fossa

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petrous face are associated with symptoms of
cerebellar dysfunction, ataxia, or elevated intra-
cranial pressure. Figure 8.1 shows the proposed
anatomic locations for each of the three petrous
face locations and the approximate relationships
to cranial nerves 5 and 7–12. Large tumors that
span the entire petrous face can be referred to as
AMPPF meningiomas.

Surgical Approaches

Most petrous face meningiomas can be exposed and
resected via a standard retrosigmoid craniotomy.
Preoperative preparation includes a volumetric
magnetic resonance (MR) imaging study with

1.25 mm slices for image guidance during sur-

gery. Since the approach is behind the mid-

coronal plane of the skull, we use scalp-based

fiducials for registering the image to physical

space. An MR venogram can be included and is

used to assess patency and dominance of the

venous sinuses preoperatively.

The patient is positioned supine with a padded

1 Liter intravenous fluid bag under the ipsilateral

shoulder, the head is secured with pins in the head

holder, and the head is rotated 60° to the opposite

side and then gently laterally extended down

toward the floor. Kidney rests are placed along the

side opposite of the exposure to secure the patient

during rotation of the body away from the surgeon,

which is used to obtain optimal lateral and superior

Fig. 8.1 Diagram of positions of meningiomas in axial and sagittal plane. APFM (a, b), MPFM (b, e). PPFM (c, f)
(Published with permission)

S.T. Magill et al.