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Chapter 16: Dorsal Cervical Decompression (Laminectomy/Hemilaminectomy and Laminotomy) 151

A B

Figure 16.2 (A) Sagittal T1‐weighted plus contrast and (B) transverse T2‐weighted MRI of a Chihuahua with a subarachnoid mass spanning the C3 and C4
vertebrae dorsally (arrows). Exposure through a dorsal laminectomy and a durotomy revealed a stage IV Dirofilaria immitis larva.

A B

Figure 16.3 A cervical hemilaminectomy was necessary to expose and remove the intradural/extramedullary mass at C3 (arrows in A, B). (A) Sagittal and
(B) dorsal T2‐weighted MRI (see also Chapter 27).

hemostat to facilitate electrocoagulation. There is almost never a tified, the muscles and fascia on the side where the surgeon is
need for vessel ligation with suture or hemostatic clips. positioned are incised and reflected from the ligament, with the
The median raphes of the cleidocervicalis, trapezius and possibly ligament then retracted to the opposite side with self‐retaining
rhomboideus muscles are divided and the paired biventer cervicus retractors. The nuchal ligaments themselves are not divided. This
muscles are separated. Dorsal branches of cervical nerves may be exposes the last group of epaxial muscles (the rectus capitis, spinalis
observed and may be transected as needed without concern for et semispinalis cervicis, and multifidus muscles) that is carefully
functional consequences. The paired but joined nuchal ligaments elevated bilaterally from the spinous processes and laminae using a
are then exposed (for all intents and purposes, though, we can con- periosteal elevator. Figure 16.5 illustrates the stages of dissection.
sider them as a single structure). Once the nuchal ligament is iden- Care is taken not to elevate these muscles too far laterally as there is