The impact of cervical spine sagittal alignment on the operative treatment of cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal dysfunction in older patients. It’s surgical treatment accounts for >100,000 operations and hospital charges in excess of $2 billion dollars in the United States alone. Little is known about how cervical sagittal alignment affects the pathogenesis and treatment of this debilitating condition. There remains no normative for cervical alignment in this patient population and few reports that correlate cervical alignment to patient outcomes. Preliminary biomechanical data at our institution suggests that an abnormal cervical sagittal alignment may place additional stress on the facets and cervical disks. Further, it may narrow the central canal and neural foramina. In addition, recent retrospective study in the literature has implicated poor neck alignment as a risk factor for post-operative disability. The long-term goal of this study is build upon our ex vivo biomechanical findings by studying the impact of cervical sagittal alignment in modern spine practice. Our central hypothesis is that abnormal cervical alignment is predictive of the development of CSM and negatively impacts post-operative clinical outcomes. Patients will obtain three-foot standing lateral graphs and research quality MRI sequences that can quantify neural loss and injury in a patient population with symptomatic CSM. Pre- and post-operative clinical outcomes will be obtained and correlated to their radiographic alignment and baseline MRIs. The primary clinical endpoint will be neck disability index (NDI) with secondary endpoints of SF-36, VAS, EQ-5d, and JOA scores. Our aims are two development normative radiographic measures for patients with symptomatic CSM and correlate these radiographic findings to pre- and post-operative clinical outcomes. We believe this will improve our understanding of the pathogenesis of this common disease and refine our knowledge of optimal surgical treatments. Further, it will serve to translate basic laboratories findings into evidence that can improve clinical care.