Indications
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Severe kyphotic deformity at the cervicothoracic spine that causes radiculopathy, myelopathy, pain, restriction of gaze, or dysphagia. The deformity may arise from postlaminectomy destabilization, junctional kyphosis above a fused level, or primary diseases affecting the spine (particularly ankylosing spondylitis).
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Dorsal osteotomy allows for greater deformity correction. Mean correction angles have been cited in the literature to range from 23.3° to 53.8° based on Cobb angles (35° to 52° based on CBV angles) compared with mean correction via ventral only approach ranging from 11° to 32°.
Planning and positioning
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All patients should have preoperative computed tomography (CT), magnetic resonance imaging (MRI), and computed tomography (CT) angiography to delineate bony, soft tissue and vascular anatomy. Neuromonitoring is needed for the operation to detect neurologic injury during closure of the osteotomy and resultant stress on the spinal cord. Imaging should be used to confirm the entry of the vertebral artery into C6 segment and to identify an ossification of the anterior or posterior longitudinal ligament. Single cassette (full spine) lateral and AP radiographs in the standing position can be useful to measure the degree of desired gaze-angle and saggital (and coronal) correction.
Figure 63-1:
The patient is positioned prone on chest rolls with Mayfield pin fixation.
Procedure
