Congenital Cervical Fusion as a Risk Factor for Development of Degenerative Cervical Myelopathy

• Published in: World neurosurgery Vol. 100; pp. 531 - 539
• Main Authors: Nouri, Aria, MD MSc, Martin, Allan R., MD, Lange, Stefan F, Kotter, Mark, MD PhD, Mikulis, David J., MD, Fehlings, Michael G., MD PhD FRCSC FACS
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2017
• Subjects: Adjacent segment degeneration; Adjacent segment disease; Adjacent segment pathology; Causality; Cervical spondylotic myelopathy; Cervical Vertebrae - abnormalities; Cervical Vertebrae - pathology; Comorbidity; Female; Humans; Klippel-Feil syndrome; Klippel-Feil Syndrome - epidemiology; Klippel-Feil Syndrome - pathology; Magnetic resonance imaging; Male; Middle Aged; Neurosurgery; Prevalence; Risk Factors; Spinal Cord Compression - epidemiology; Spinal Cord Compression - pathology; adjacent segment pathology; adjacent segment degeneration; modified Japanese Orthopaedic Association score; OPLL; MRI; Klippel-Feil Syndrome; CCF; Congenital Cervical Fusion; Ossification of the Posterior Longitudinal Ligament; Cervical Spondylotic Myelopathy; adjacent segment disease; ICF; DCM; Magnetic Resonance Imaging; CT; NDI; Neck Disability Index; Idiopathic Cervical Fusion; KFS; Degenerative Cervical Myelopathy; Computed Tomography; mJOA; Magnetic resonance imaging; Adjacent segment disease; Adjacent segment degeneration; Klippel-Feil syndrome; Cervical spondylotic myelopathy; Adjacent segment pathology
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2017.01.048

Abstract Background Congenital fusion of cervical vertebrae, including Klippel-Feil Syndrome (KFS), is a suspected risk factor for development of degenerative cervical myelopathy (DCM). We aimed to establish prevalence and degenerative patterns of congenital cervical fusion (CCF) among a global cohort of patients with DCM. Methods Data from three prospective DCM studies were merged, including clinical data for 813 patients and imaging for 592 patients. CCF was diagnosed by presence of fused cervical vertebrae without signs of degenerative fusion. A wasp-waist sign was used to define a KFS subgroup. Characteristics of patients with CCF and the KFS subgroup were compared with the remainder of DCM patients. Results Twenty-three CCF patients (14 KFS) were identified, resulting in a prevalence of 3.9% (2.4% KFS). Patients with CCF were older (p=0.02), had more operated levels (p=0.01), had greater rates of OPLL (p=0.02), and demonstrated worse degenerative changes at C3-4, including spinal cord compression (p=0.002) and T2WI signal hyperintensity (p=0.04). Levels adjacent to fusions showed a trend toward increased spinal cord compression (p=0.09), with fusions at C3-4 or above showing cord compression below in 9/10 patients, fusions at C5-6 or below having cord compression above in 8/8 patients, and 2/2 patients with C4-5 fusion having cord compression above and below. Conclusion The prevalence of CCF and KFS is greater in DCM than for the general population, suggesting that these patients are predisposed to DCM development. CCF patients also have an altered pattern of degenerative changes, seemingly related to adjacent segment degeneration that preferentially affects mid-cervical levels.