94
bone drilling and dural coagulation, thereby reduc-
ing their growth potential [ 12 , 19 ]. This strategy is
especially used in younger patients who have a
higher risk of long-term radiation toxicity.
Surgical resection has been the standard of
care for PC meningiomas in the present micro-
neurosurgical era, although the aggressiveness
of tumor resection has decreased over the past
two decades in an effort to reduce iatrogenic
neurological deficits. Surgery is primarily con-
sidered for young, symptomatic patients with
rapidly growing tumors and no/minimal sys-
temic comorbidities, patients with larger tumors
causing brainstem compression and multiple
cranial neuropathies, and cases where the diag-
nosis of benign lesion is in doubt [ 1 , 3 , 4 ]. The
aim of the surgical intervention is maximal safe
resection (complete if possible) of tumor with-
out causing undue traction to surrounding neu-
rovascular structures to minimize iatrogenic
neurological deficits. The goals of surgery
include establishing the histological diagnosis,
achieving brainstem and cranial nerves decom-
pression to facilitate improvement in functional
outcome, and reducing tumor volume to smaller
dimensions making it compatible to SRS adju-
vant therapy (especially tumors extending into
cavernous sinus). Intraoperative assessment of
the tumor-brainstem interface is critical, as
overzealous attempts at radically removing firm
and adherent tumors stuck to brainstem may
lead to catastrophic sequelae. Lastly, use of neu-
roendoscopy, neuronavigation, and electrophys-
iological monitoring intraoperatively can
contribute toward a safe surgery and optimal
patient outcome [ 11 ].
Surgical Approaches
The basic tenets of skull base surgery include
optimal patient positioning to help gravity-
assisted retraction; use of intraoperative lumbar
drain to facilitate brain relaxation for easy access
to the tumor, moving from one anatomical land-
mark to another to ensure precise surgical expo-
sure and maximal use of the operative corridor;
early devascularization of the tumor via drilling
of involved bone and coagulating tumor feeders
along the involved dura mater; and maintaining
the arachnoid plane between the tumor and the
surrounding vital neurovascular structures. The
rationale for choosing each skull base approach
optimizes the balance between iatrogenic mor-
bidity due to the approach and the need to limit
brain retraction for good visualization of neuro-
vascular structures involved. Broadly speaking,
the surgical approaches to the PC region are
divided into transfacial and transcranial
approaches (Fig. 7.2) [ 11 ]. Transfacial approaches
can utilize transoral, transsphenoidal, or trans-
maxillary surgical corridors for accessing the PC
region. Advances in the realm of neuroendos-
copy, the availability of precise neuronavigation
systems, and development of better hemostatic
agents have provided a much-needed boost to
efforts to resect large PC meningiomas via mini-
mally invasive transfacial approaches. At present,
however, the data to support long-term safety and
efficacy for this purpose are lacking.
On the contrary, transcranial approaches have
stood the test of time for resecting PC meningio-
mas safely. They are further subdivided based on
the surgical trajectory taken to reach the PC
region: anterior/anterolateral and lateral/postero-
lateral approaches [ 1 , 3 , 4 , 11 ]. The principal
anterior approach is the transbasal transplanum
transclival approach, which has traditionally
been used for extensive and more midline tumors
such as clival chordoma and craniopharyngioma,
especially involving anterior and middle cranial
fossa. Access to the petroclival region is limited
for tumors involving the inferior half of the clivus
and extending lateral to the internal acoustic
meatus. Cavernous sinus and Meckel’s cave
involvement further limits surgical access via this
approach. Anterolateral approaches include the
pterional, orbitozygomatic, and transzygomatic
subtemporal/pretemporal approaches [ 1 , 3 , 4 ,
11 ]. They are primarily utilized for tumors with
their epicenters/tumor bulk in the supratentorial
compartment, which are difficult to access via
lateral/posterolateral approaches. The primary
disadvantages to these approaches are limited
access to tumor extending to the contralateral
side across ventral brainstem, utilization of aA. Raheja and W.T. Couldwell