189higher incidence of LMD than en bloc resection,
but there was no significant increase in LMD in
the SRS treatment arm versus the surgical resec-
tion arm of the analysis [ 55 ]. Finally, the neuro-
surgical oncologist must be aware of the varying
tumor biologies posed by metastatic lesions to
the brain. Vascular tumors such as renal cell car-
cinoma, thyroid cancer, and melanoma are prob-
ably best devascularized externally before
attempting removal, and an en bloc approach is
preferred for these lesions, if feasible. Other
lesions such as breast cancer and lung cancer can
be very friable, making en bloc resection diffi-
cult. After the tumor is resected, hemostasis
should be a priority within the tumor cavity.
Gelfoam and Surgicel may be applied to the cav-
ity, initiating hemostatic cascades and reducing
oozing of blood into the subarachnoid space.
CSF flow pathways should be examined and
cleared of debris. The dura can then be closed in
a watertight fashion, and a Valsalva maneuver
should be performed to assess the seal. A dural
patch is a norm rather than an exception. The
bone flap is replaced if a craniotomy has been
performed. Muscle is closed in multiple layers to
ensure a tight, secure, postoperative surgical site.
Postoperative Care
and Complications
The postoperative period is critical after posterior
fossa surgery. Patients should receive an immedi-
ate postoperative CT scan if there are any new
neurological deficits. Otherwise, unless the iMRI
has been used for the case, a postoperative MRI
with and without contrast should occur within
72 h of surgery to define the extent of resection
and guide future care. Patients who have EVDs
placed preoperatively will be gradually weaned
as tolerated or converted to a permanent shunt.
Common complications during the postop-
erative period after posterior fossa surgery
include double vision, hearing loss, facial
nerve weakness, and swallowing difficulty.
Respiratory depression and hydrocephalus are
the leading causes of rapid patient deteriora-
tion. The constricted space of the posterior
fossa allows for neurological decompensation
to occur much more quickly and without atten-
dant supratentorial signs (confusion, etc.),
which typically signal a progressively deterio-
rating clinical picture in most brain surgery.
Loss of brainstem function secondary to surgi-
cal injury or hydrocephalic compression may
preclude spontaneous respiration and prevent
weaning from ventilation after surgery. Cranial
nerves should be meticulously monitored in
the postoperative period. A rare, but particu-
larly troublesome, complication of posterior
fossa tumor resection is the so-called posterior
fossa syndrome (PFS). PFS is described as a
collection of symptoms including cranial nerve
deficits, nausea, transient mutism, emotional
lability, and other cerebellar signs such as
imbalance and ataxia. These symptoms appear
to be most common after radical and aggres-
sive resection of tumors adjacent to the lateral
fourth ventricular borders [ 62 ]. Not surpris-
ingly, these symptoms may cause patients and
their families great anguish throughout the
postoperative and follow-up period. An early
rehabilitation medicine consultation, and
immediate initiation of physical therapy, may
speed recovery if a patient begins to manifest
PFS. However, with time, most symptoms tend
to resolve on their own.
Late common complications in the postopera-
tive period after posterior fossa surgery include
wound infection and pseudomeningocele. A
pseudomeningocele, by definition, is a collection
of CSF outside the dura. This may occur after
posterior fossa surgery because of a failure of
dural closure but in many cases is due to hydro-
cephalus/increased intracranial pressure. This
once again calls to mind the attention to detail
necessary for dural closure in the posterior fossa.
Pseudomeningoceles must be identified early,
and many can resolve over time or with place-
ment of a lumbar drain. Rarely, the CSF leakage
can transgress the wound closure, with the poten-
tial for meningitis. These leaks need to be treated
emergently to wash out and close the wound to
prevent further infectious complications.13 Metastasis to the Posterior Fossa