Current Concepts of Cervical Spine Alignment, Sagittal Deformity, and Cervical Spine Surgery

Abstract

There are not many reports on cervical spine alignment, and only a few analyze ideal surgical approaches and optimal amounts of correction needed for the various types of deformity. We comprehensively reviewed the present literature on cervical spinal deformities (with or without myelopathy) and their surgical management to provide a framework for surgical planning. A general assessment of the parameters actually in use and correlations between cervical and thoracolumbar spine alignment are provided. We also analyzed posterior, anterior, and combined cervical surgical approaches and indications for the associated techniques of laminoplasty, laminectomy and fusion, and anterior cervical discectomy and fusion. Finally, on the basis of the NDI, SF-36, VAS, and mJOA questionnaires, we fully evaluated the outcomes and measures of postoperative health-related quality of life. We found the need for additional prospective studies to further enhance our understanding of the importance of cervical alignment when assessing and treating cervical deformities with or without myelopathy. Future studies need to focus on correlations between cervical alignment parameters, disability scores, and myelopathy outcomes. Through this comprehensive literature review, we offer guidance on practical and important points of surgical technique, cervical alignment, and goals surgeons can meet to improve symptoms in all patients.

Keywords: cervical spine alignment; cervical spondylotic myelopathy; degenerative cervical myelopathy; laminoplasty; posterior fusion.

Figure 1

Pathology of degenerative cervical myelopathy.

Figure 2

Cervical spine alignment parameters. SVA, sagittal vertical alignment.

Figure 3

Flowchart listing the screening process for this systematic review.

Figure 4

Surgical technique of Z-plasty, the origin of cervical laminoplasty. (1) Removing the spinal processes, (2) grinding and eliminating the dorsal cortical bone and cancellous bone of the laminae with an air drill, (3) incising a Z-shaped thinned laminae, leaving the ligamenta flava between the laminae intact, and (4) tying the laminae with two sutures; thus, enlargement of the spinal canal is obtained.

Figure 5

K-line.