© Springer International Publishing AG 2018 65
W.T. Couldwell (ed.), Skull Base Surgery of the Posterior Fossa,
https://doi.org/10.1007/978-3-319-67038-6_5
Far Lateral Approach
and Its Variants
Karolyn Au, Angela M. Richardson,
and Jacques Morcos
K. Au, MD, MSc • A.M. Richardson, MD, PhD
J. Morcos, MD, FRCS(Eng), FRCS(Ed), FAANS (*)
Department of Neurological Surgery, University of
Miami/Jackson Memorial Hospital, Miami, FL, USA
e-mail: [email protected]
5
Introduction
A general surgical principle is worth stating at
the outset of this chapter: choice of surgical
approach is entirely determined by the nature and
extent of the pathology. A large, soft, avascular
tumor of the craniovertebral junction such as a
schwannoma, paradoxically, may require a
smaller exposure than a small ruptured but high
PICA/VA aneurysm. Tumors displace the sur-
rounding anatomy and in the process provide a
surgical path to their own resection; one may call
this a “trans-tumor” corridor. Vascular lesions
such as aneurysms, AVMs, and cavernomas do
not do this, and choosing the exactly appropriate
approach in these instances is perhaps more
important. A rote approach to neurosurgery is
inappropriate and counterproductive, and in the
decision-making process, the surgeon must inte-
grate considerations of the anatomy, location,
and texture of the pathology.
Having said that, there are general principles
that apply, particularly regarding the surgical
approaches to the foramen magnum/cranioverte-
bral junction region. Accessing the anterior and
anterolateral foramen magnum is a challenge due
to the numerous neurologic, vascular, and
ligamento- osseous structures that must be tra-
versed along a deep corridor. A direct anterior tra-
jectory is limited by vital structures laterally, so a
posterolateral approach is commonly employed.
The far lateral technique thus creates an exposure
via a suboccipital craniotomy and removal of the
foramen magnum rim to the occipital condyle,
along with removal of the posterior arch of C1 to
the lateral mass of C1. Its supracondylar, trans-
condylar, and paracondylar variants incorporate
additional removal of lateral structures such as the
occipital condyle, C1 lateral mass, jugular tuber-
cle, and jugular process. The successive gains in
anterolateral exposure and widened working cor-
ridor must be balanced against increased risk of
injury to the vertebral artery, jugular bulb, and
lower cranial nerves, as well as destabilization of
the atlanto-occipital junction.Anesthetic Technique and
Positioning
Optimizing safety of surgery around the lower
brainstem requires particular consideration and
communication between the surgical and anes-
thetic teams. To minimize the need for brain
retraction, standard anesthetic measures to facili-
tate brain relaxation are employed including
hyperventilation and mannitol administration.