International Variations in the Clinical Presentation and Management of Cervical Spondylotic Myelopathy. One Year Outcomes of the AOSpine Multi-Center Prospective Study. On Behalf of the CSM-I Site Investigators : Michael Fehlings, MD, University of Toronto, Toronto, ON, Canada; Branko Kopjar, MD, University of Washington, Seattle, WA; Ronald Bartels, MD, University Nijmegen Medical Centre, Nijmegen, Netherlands; Vincenzo Albanese, PhD, Medical University of Catania, Catania, Italy; Helton Defino, MD, University of Sao Paulo - Ribeirao Preto, Sao Paulo, Brazil; Paul Arnold, MD, University of Kansas, Kansas City; Qiang Zhou, MD, Southwestern Hospital, ChongQing, China; Mehmet Zileli, MD, Ege University, Izmir, Turkey; Gamaliel Tan, MD, Tan Tock Seng Hospital, Singapore, Singapore; Osmar Moraes, MD, Hospital Santa Marcelina, Sao Paulo, Brazil; Shashank Kale, MD, All India Institute of Medical Sciences, New Dehli India; Ciaran Bolger, MD, Beaumont Hospital, Dublin, Ireland; Manuel Alvarado, MD, Hospital San Juan de Dios, Caracas, Venezuela; Massimo Scerrati, MD, Medical University of Ancona, Ancona, Italy Giuseppe Barbagallo, MD University of Catania, Catania, Italy

Background  Cervical spondylotic myelopathy (CSM) is the commonest cause of spinal cord impairment.  There is a lack of evidence regarding the long term outcomes of surgical treatment for CSM.  We report on the one year outcomes of a large prospective multicenter study to evaluate the impact of surgery on outcomes of CSM.

Patients 379 patients with clinically confirmed CSM and imaging evidence of cord compression (MRI or CT-myelogram) were enrolled in the prospective cohort study. Patients underwent anterior surgery (discectomy/corpectomy and instrumented fusion) or posterior surgery (laminectomy and fusion or laminoplasty) based on the judgment of the operating surgeon.

Subjects accounting 379 subjects were enrolled at 13 sites around the world. One year follow-up data are currently available for 193 subjects. Outcomes evaluations –modified Japanese Orthopaedic Assessment scale (mJOA), Nurick Score, Neck Disability Index (NDI), Short Form-36v2, and an assessment of treatment complications.

Primary Investigators and Regions RegionCity Primary Investigator North America TorontoDr. M. Fehlings Kansas CityDr. P. Arnold Asia / Pacific ChongQingDr. Q. Zhou New DehliDr. S. Kale SingaporeDr. G. Tan Latin America Ribeirao PretoDr. H. Defino Sao PauloDr. O. Moraes CaracasDr. M. Alvarado Europe NijmegenDr. R. Bartels IzmirDr. M. Zileli DublinDr. C. Bolger CataniaDr. G. Barbagallo AnconaDr. M. Scerrati

Demographics VariableAnterior (N=224)Posterior (N=144)Circumferential (N=9)P-value Age54.0± ± ±9.2<.01 Male Gender55.3%73.5%44.44%<.01 mJOA12.9± ±2.912±2.8<.01 Nurick4.1±1.14.6±1.44.8±1.3<.01 NDI38.5± ± ± SF36 V2 PCS35.6± ± ± SF36 V2 MCS38.7± ± ± Levels2.95±.94.7±.93.9±0.9<.01

12 months outcomes (N=193) VariableBaseline12 MonthsP value mJOA 12.5± ±2.7 <.01 Nurick 4.3±1.22.9±1.5 <.01 NDI 38.2± ±19.1 <.01 SF36 PCS 35.1± ±10.1 <.01 SF36 MCS38.8± ±10.6<.01

12 months outcomes (N=193) - mJOA

Regional Differences in Demographics Variable North America (N =113) Latin America (N =43) Europe (N =123) Asia pacific (N =57) P value Age59.7± ± ± ±13.2<.001 Male Gender57.0%71.1%59.3%70.3%<.001 Surgery<.001 Anterior56.7%23.1%72%67.5% Posterior39.2%76.9%24.8%32.5% Circumferential4.1%0%3.2%0% Number of levels4.2±1.34.1±1.13.2±1.03.3±1.2<.001 VariableNorth AmericaLatin AmericaEuropeAsia PacificP Value MJOA12.2± ± ± ±3.2n.s. NDI37.6± ±20.637± ±20.3n.s. Nurick4.2±1.04.4±1.64.2±1.24.6±1.4n.s. PCS35.3± ± ± ±8.2n.s. MCS39.2± ± ± ±9.4n.s. Regional Differences in Baseline Variables

Regional Differences in Outcomes VariableNorth AmericaLatin AmericaEuropeAsia Pacific P value mJOA2.76(0.29)2.07(0.38)1.30(0.28)2.92(0.39) NDI7.21(2.42)10.24(3.20)8.23(2.28)12.42(4.31) Nurick1.56(0.17)0.62(0.23)1.18(0.16)1.45(0.23) PCS6.06(1.22)10.53(1.52)4.58(1.12)12.35(1.55) MCS5.04(1.30)8.91(1.63)3.17(1.19)9.77(1.66) *Values in table show changes in outcome between baseline and 12 months adjusted for baseline predictors. Numbers in parenthesis are standard error.

Surgical treatment for CSM results in sustained improvement in generic and disease HRQOL The amount of improvement varied across the regions. –Subjects from Asia & Pacific and Latin America had larger improvements in outcome than those from North America and Europe. –The impact of differences in age (much younger in Asia/Pacific) and socio-cultural perceptions of disability and impairment likely play a role in these observations Discussion

Acknowledgements Study is funded by AOSpine International, a non-for-profit organization for excellence in spine.