Efficacy and safety of surgical decompression in patients with cervical spondylotic myelopathy: results of the AOSpine North America prospective multi-center study.
BACKGROUND
Cervical spondylotic myelopathy is the leading cause of spinal cord dysfunction worldwide. The objective of this study was to evaluate the impact of surgical decompression on functional, quality-of-life, and disability outcomes at one year after surgery in a large cohort of patients with this condition.


METHODS
Adult patients with symptomatic cervical spondylotic myelopathy and magnetic resonance imaging evidence of spinal cord compression were enrolled at twelve North American centers from 2005 to 2007. At enrollment, the myelopathy was categorized as mild (modified Japanese Orthopaedic Association [mJOA] score ≥ 15), moderate (mJOA = 12 to 14), or severe (mJOA < 12). Patients were followed prospectively for one year, at which point the outcomes of interest included the mJOA score, Nurick grade, Neck Disability Index (NDI), and Short Form-36 version 2 (SF-36v2). All outcomes at one year were compared with the preoperative values with use of univariate paired statistics. Outcomes were also compared among the severity classes with use of one-way analysis of variance. Finally, a multivariate analysis that adjusted for baseline differences among the severity groups was performed. Treatment-related complication data were collected and the overall complication rate was calculated.


RESULTS
Eighty-five (30.6%) of the 278 enrolled patients had mild cervical spondylotic myelopathy, 110 (39.6%) had moderate disease, and 83 (29.9%) had severe disease preoperatively. One-year follow-up data were available for 222 (85.4%) of 260 patients. There was a significant improvement from baseline to one year postoperatively (p < 0.05) in the mJOA score, Nurick grade, NDI score, and all SF-36v2 health dimensions (including the mental and physical health composite scores) except general health. With the exception of the change in the mJOA, the degree of improvement did not depend on the severity of the preoperative symptoms. These results remained unchanged after adjusting for relevant confounders in the multivariate analysis. Fifty-two patients experienced complications (prevalence, 18.7%), with no significant differences among the severity groups.


CONCLUSIONS
Surgical decompression for the treatment of cervical spondylotic myelopathy was associated with improvement in functional, disability-related, and quality-of-life outcomes at one year of follow-up for all disease severity categories. Furthermore, complication rates observed in the study were commensurate with those in previously reported cervical spondylotic myelopathy series.
Division of Neurosurgery, University of Toronto, Toronto Western Hospital, West Wing, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada. E-mail address for M.G. Fehlings: Michael.Fehlings@uhn.on.ca.
Michael G
MG
Fehlings
Jefferson R
JR
Wilson
Branko
B
Kopjar
Sangwook Tim
ST
Yoon
Paul M
PM
Arnold
Eric M
EM
Massicotte
Alexander R
AR
Vaccaro
Darrel S
DS
Brodke
Christopher I
CI
Shaffrey
Justin S
JS
Smith
Eric J
EJ
Woodard
Robert J
RJ
Banco
Jens R
JR
Chapman
Michael E
ME
Janssen
Christopher M
CM
Bono
Rick C
RC
Sasso
Mark B
MB
Dekutoski
Ziya L
ZL
Gokaslan
D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000473:pathology* / Q000601:surgery; D019299:Decompression, Surgical / Q000009:adverse effects / Q000379:methods*; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009656:North America; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D011446:Prospective Studies; D011788:Quality of Life; D012720:Severity of Illness Index; D013118:Spinal Cord Diseases / Q000150:complications* / Q000601:surgery; D013128:Spinal Osteophytosis / Q000150:complications* / Q000601:surgery; D016896:Treatment Outcome