99this single approach, even tumors with significant
supratentorial extension. This approach provides
the widest exposure to PC tumors having multi-
compartmental spread and extensions across the
midline, allowing their safe resection, along with
good visualization of the tumor brainstem inter-
face. In-depth evaluation of venous drainage pat-
terns and anatomy is again pertinent to plan this
approach to optimize the patient outcome.
Surgical Technique and Nuances
The senior surgeon prefers the lateral position
for a combined petrosal approach. The incision
is marked in a large quadrangular fashion with
the anterior limb curving back from 1 cm in
front of the tragus along superior temporal line
and the posterior limb extending in the retroau-
ricular region along the hairline, ending approx-
imately 1 cm inferior to the mastoid tip [ 11 , 24 ].
A combined supratentorial (temporal) and
infratentorial (suboccipital) craniotomy is made
across the transverse sinus (Fig. 7.3). The senior
author performs a cosmetic mastoidectomy for
the approach [ 25 ]. The outer table of the mas-
toid is undercut by an oscillating saw or drill to
allow replacement as a bone flap at closure [ 24 ].
A complete mastoidectomy is performed next
by drilling along the mastoid triangle, which is
bounded anteriorly by the posterior ear canal,
superiorly by the inferior temporal line, and
posteriorly by the occipital bone. Next, the
boundaries of Trautmann’s triangle—the sig-
moid sinus posteriorly, the superior petrosal
sinus superiorly, and the posterior SCC anteri-
orly—are exposed. Once the appropriate bony
exposure is completed to achieve the anterior
petrosectomy and intended posterior petrosec-
tomy, the dura is incised in a curvilinear fashion
from the subtemporal region to the presigmoid
region. The superior petrosal sinus is ligated
and divided proximal to the drainage site of the
vein of Labbé into the sigmoid transverse sinus
junction to prevent venous infarct of the tempo-
ral lobe [ 11 , 24 ]. The tentorium is then divided
posterior to the entry point of the trochlear nerve
to complete the exposure. The dural defect can
be plugged using pericranial graft, myofascial
flap, and autologous fat graft.
Complications and Their Avoidance
Apart from the typical set of complications and
their prevention techniques for anterior and pos-
terior transpetrosal approaches (see above), par-
ticular attention needs to be given to a few aspects
including a risk of CSF leak and the risk of
venous infarcts. If a cosmetic mastoidectomy is
performed, there is no bony defect associated
with the approach. A vascularized pedicled myo-
fascial flap based on the sternocleidomastoid
muscle and temporalis fascia is an invaluable
option to plug the large dural defect created by
combined petrosectomy approach to reduce the
incidence of CSF leak [ 24 ]. The risk of venous
infarct can be reduced by dividing the SPS as
proximal as possible to maintain the petrosal vein
drainage as well as that of vein of Labbé. Lastly,
another important modification of the combined
petrosectomy has been proposed to reduce the
time of surgery and its associated anesthesia- and
blood loss-related complications [ 26 ]. It includes
anterior petrosectomy along with the petrous api-
cectomy in place of conventional posterior petro-
sectomy approaches, which helps reduce
operative time and associated morbidity without
sacrificing much of the operative exposure.Treatment Outcomes
in the Multimodality
Management Era
The assessment of postoperative outcome has
been done conventionally using tools such as
Karnofsky Performance Status score, Glasgow
Outcome Scale, and Modified Rankin Scale [ 24 ].
More recently, Morisako et al. [ 24 ] devised a pet-
roclival meningioma impairment scale, which is
specifically designed for more comprehensive
assessment of patients with PC meningiomas.
Gross total resection rates have improved over
time, and they presently range from 20% to 79%
[ 11 ]. Although new-onset iatrogenic cranial neu-
ropathies or worsening of preexisting nerve defi-
cits has been reported to occur in as many as 76%
of patients, the majority are transient in nature,
and long-term data suggest a return to preopera-
tive status with no/minimal limitation of activi-7 Petroclival Meningiomas