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11 Lateral (Rostrotentorial) Craniotomy/

Craniectomy

Andy Shores

Introduction Craniectomies are far more commonly performed than craniotomies
This approach was developed and published by Dr. J.E. Oliver in the in veterinary neurosurgery. Because the large temporalis muscle
mid 1960s [1]. The basics have changed little in the ensuing half‐ covers the skull defect, cosmetic defects are uncommon, and the
century. Dr. Oliver described this approach for exposing the “fron- muscle mass affords more than adequate protection of the exposed
tal, parietal, temporal, and occipital lobes” [2]. Indications for this cortex after closure. The author always uses a dural substitute (bio-
approach include intracranial tumors (Figure 11.1), aberrant blood logical or synthetic) and usually places a synthetic polypropylene
vessels (congenital, acquired) [3], traumatic brain injury (Figure 11.2), mesh over the skull defect. These measures help prevent adhesions
brain abscesses, and cerebral biopsy [4]. between muscle and cortical tissue.
Regions of the brain in dogs and cats are not as clearly definable
as in humans; however, for orientation purposes, the regions to Patient Preparation and Positioning
consider are the olfactory, frontal, parietal, temporal, and occipital. Standards for preoperative patient preparation apply, concluding in
Variations of the lateral craniectomy are used to approach all of clipping the head on both sides, laterally to below the zygomatic arches,
these regions except for the olfactory lobe. The olfactory lobe and rostrally to just dorsal to the orbit, caudally to the level of C1, with a
some lesions of the frontal lobe are best approached using trans- sterile skin preparation after the patient is positioned on the operating
frontal craniotomy. table (Figure 11.3). Because the ears are draped out of the operating
field in most procedures, it is unnecessary to clip the outer ear pinna.
The patient is positioned on a padded operating table in sternal
recumbency. Beaded Styrofoam vacuum bags, sand bags, or a head
stand are used to position the head with the mandible parallel to the
table without pressure on the jugular veins. It is very important to
have the head positioned correctly and firmly fixed in position to
prevent movement during the procedure. If the planned lateral
craniectomy is considerably more ventral than midline, having the
head rotated slightly away from the surgeon can aid in gaining ade-
quate exposure. The surgeon should be in the operating room at the
time of positioning to ensure it is correctly done for the planned
procedure. After the final sterile preparation, the patient is quarter
draped and the surgery can begin.

Surgical Technique
Figure 11.1 Transverse T1‐weighted postcontrast MRI of a canine meningi- A curvilinear (horseshoe‐shaped) incision is made beginning just
oma. This mass would be approached using a lateral rostrotentorial caudal and medial to the lateral canthus of the eye, to the dorsal
craniectomy. midline, and then curving caudally and ventrally to behind the ear

Current Techniques in Canine and Feline Neurosurgery, First Edition. Edited by Andy Shores and Brigitte A. Brisson.
© 2017 John Wiley & Sons, Inc. Published 2017 by John Wiley & Sons, Inc.
Companion website: www.wiley.com/go/shores/neurosurgery

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