AAOS Comprehensive Orthopaedic Review 4: Print + Ebook (AAOS - American Academy of Orthopaedic Surgeons)

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15 | Degenerative Conditions of the Cervical Spine

H. Laminectomy with fusion 1. Potential benefits

4. Supplemental posterior fixation and fusion may be prudent if a long strut graft is necessary ante riorly to provide better stability and reduce the incidence of graft kickout and pseudarthrosis. 5. All anterior fusion procedures carry relatively small but real risks intrinsic to the anterior approach, such as permanent speech and swallowing dis turbance, airway obstruction, esophageal injury, and vertebral artery injury; the risks are probably higher for multilevel reconstructions than for a single-level or two-level ACDF because of longer surgical times and the number of levels exposed. K. Laminoplasty 1. Overview a. Laminoplasty (initially used in Japan) is gain ing wider acceptance in North America. This technique achieves multilevel posterior cord decompression while avoiding postlaminec tomy kyphosis. b. Common to all variations of the procedure is the expansion of the spinal canal, usually through creation of a hinge at the junction of the lateral mass and lamina. The hinge is created by thin ning the dorsal cortex but not cutting through the ventral cortex completely, allowing the cre ation of the hinge through a greenstick fracture. c. A C4 through C6 procedure is performed in most cases. A laminectomy of C3, instead of laminoplasty, is favored because it necessitates less disruption of the semispinalis cervicis (the major extensor muscle of the neck) at its C2 attachment. In addition, a laminoplasty of C3 tends to abut the spinous process of C2 and interfere with full neck extension. Ideally, C7 laminoplasty should be avoided because includ ing that level increases the risk of neck pain. d. A recent multicenter, prospective randomized study comparing anterior versus posterior sur gery demonstrated the advantage of lamino plasty in appropriately selected patients over laminectomy and fusion, as well as anterior surgery. e. Contraindications: neck pain, focal kyphosis greater than 15°, anterior lesions that extend posterior to the K-line (drawn from the center of the spinal cord from the cranial to the cau dal extent of the decompression), C2-7 sagittal vertical axis greater than 35 to 40 mm 2. Surgical techniques

a. Improvement of spondylotic neck pain and avoidance of postlaminectomy kyphosis b. Preexisting kyphosis can be improved after laminectomy by positioning the neck in exten sion before securing the instrumentation; for higher degrees of kyphosis, an anterior- posterior approach is generally recommended. 2. Despite the advantages of laminectomy with fusion over laminectomy alone, it may be outper formed by alternative procedures such as lamino plasty or anterior-based procedures. 3. When fusion is not necessary, laminoplasty may be a better choice. I. ACDF 1. ACDF can directly decompress structures most commonly responsible for cord compression, such as herniated disks, spondylotic bars, and OPLL. 2. ACDF also can directly relieve neural compres sion resulting from kyphosis by removing the ver tebral bodies over which the cord may be draped, as well as improve alignment. 3. The procedure helps to relieve spondylotic neck pain, can correct and improve kyphosis, immo bilizes and therefore protects the segment of decompressed cord, and prevents recurrent dis ease over the fused segments. 4. Excellent neurologic recovery rates have been reported with anterior surgery for myelopathy. 5. For myelopathy arising from one or two disk spaces, a single-level or two-level ACDF (or a single-level corpectomy for two-motion-segment disease) is the treatment of choice for most patients. For patients with stenosis at three or more disk segments, however, the superiority of an anterior approach is not clear-cut. J. Multilevel anterior corpectomy and fusion 1. Pseudarthrosis rates after multilevel anterior cor pectomy and fusion range from 11% to 40%. 2. Graft dislodgment, reported to occur in 7% to 20% of patients, can be associated with neuro logic compromise, esophageal injury, and even airway obstruction resulting in death. 3. Nonplated corpectomies with long strut grafts have shown good clinical results but require cum bersome rigid external immobilization and have been associated with the morbidity of autologous fibular harvest.

2 | Spine

a. Open door and French door are the most com mon types of laminoplasty. The differences between these techniques are listed in Table 3 . Copyright © Wolters Kluwer, Inc. Unauthorized reproduction of the content is prohibited. 2023

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AAOS Comprehensive Orthopaedic Review 4