STUDY DESIGN: Retrospective cross-sectional study. OBJECTIVE: Determine if pre-operative cervical alignment serves as an independent predictor of pre-operative disability as measured by the neck disability index (NDI). SUMMARY OF BACKGROUND DATA: There is growing interest in the relationship between cervical sagittal alignment and clinical outcomes. While prior studies have shown that C2-C7 sagittal vertical axis (SVA) correlates with worse NDI scores in post-operative patients, no studies to date have examined the impact of cervical sagittal parameters on pre-operative disability in patients indicated for surgery. METHODS: Patients with pre-operative standing cervical radiographs, no prior cervical spine procedures and a pre-operative NDI score were identified. Measurements were made by two observers at two different time points. Parameters measured were: Occiput-C2 angle, C1-C2 angle, C2-C7 angle (CL), T1 slope (TS), TS minus CL (TS-CL), C2-C7 SVA, and C1-C7 SVA. Intra- and inter-observer reliability was calculated. Subgroup analyses of myelopathy vs. radiculopathy and deformity vs. no deformity was performed. A multivariate linear regression was performed. RESULTS: Ninety patients were included. Indications included cervical myelopathy (n = 63), cervical radiculopathy (n = 25), cervical stenosis (n = 9), and others (n = 5). CL averaged -13.7 ± 14.9 degrees. TS averaged 30.7 ± 10.4 degrees and C2-C7 SVA averaged 28.8 ± 13.2 mm. Intra- and inter-observer reliability was good to excellent (ICC > 0.8). Increasing CL (r = 0.277, P = 0.009), increasing TS (r = -0.273, P = 0.011) and increasing TS-CL (r = -0.301, P = 0.005) were correlated with decreasing NDI. CL, TS and TS-CL were also strongly correlated with each other (r > 0.65, P < 0.001 for all bivariate correlations). A multivariate regression adjusting for age and indication showed TS-CL (P = 0.040) and C2-C7 SVA (P = 0.015) were independent predictors of NDI. CONCLUSION: Increasing CL, increasing TS and increasing TS-CL are correlated with decreasing pre-operative NDI. Low TS-CL and high C2-C7 SVA are independent predictors of high pre-operative NDI. LEVEL OF EVIDENCE: 4.
STUDY DESIGN: Retrospective cross-sectional study. OBJECTIVE: Determine if pre-operative cervical alignment serves as an independent predictor of pre-operative disability as measured by the neck disability index (NDI). SUMMARY OF BACKGROUND DATA: There is growing interest in the relationship between cervical sagittal alignment and clinical outcomes. While prior studies have shown that C2-C7 sagittal vertical axis (SVA) correlates with worse NDI scores in post-operative patients, no studies to date have examined the impact of cervical sagittal parameters on pre-operative disability in patients indicated for surgery. METHODS:Patients with pre-operative standing cervical radiographs, no prior cervical spine procedures and a pre-operative NDI score were identified. Measurements were made by two observers at two different time points. Parameters measured were: Occiput-C2 angle, C1-C2 angle, C2-C7 angle (CL), T1 slope (TS), TS minus CL (TS-CL), C2-C7 SVA, and C1-C7 SVA. Intra- and inter-observer reliability was calculated. Subgroup analyses of myelopathy vs. radiculopathy and deformity vs. no deformity was performed. A multivariate linear regression was performed. RESULTS: Ninety patients were included. Indications included cervical myelopathy (n = 63), cervical radiculopathy (n = 25), cervical stenosis (n = 9), and others (n = 5). CL averaged -13.7 ± 14.9 degrees. TS averaged 30.7 ± 10.4 degrees and C2-C7 SVA averaged 28.8 ± 13.2 mm. Intra- and inter-observer reliability was good to excellent (ICC > 0.8). Increasing CL (r = 0.277, P = 0.009), increasing TS (r = -0.273, P = 0.011) and increasing TS-CL (r = -0.301, P = 0.005) were correlated with decreasing NDI. CL, TS and TS-CL were also strongly correlated with each other (r > 0.65, P < 0.001 for all bivariate correlations). A multivariate regression adjusting for age and indication showed TS-CL (P = 0.040) and C2-C7 SVA (P = 0.015) were independent predictors of NDI. CONCLUSION: Increasing CL, increasing TS and increasing TS-CL are correlated with decreasing pre-operative NDI. Low TS-CL and high C2-C7 SVA are independent predictors of high pre-operative NDI. LEVEL OF EVIDENCE: 4.
Authors: Bassel G Diebo; Neil V Shah; Maximillian Solow; Vincent Challier; Carl B Paulino; Peter G Passias; Renaud Lafage; Frank J Schwab; Han Jo Kim; Virginie Lafage Journal: Orthopade Date: 2018-06 Impact factor: 1.087
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Authors: Avinash G Patwardhan; Saeed Khayatzadeh; Robert M Havey; Leonard I Voronov; Zachary A Smith; Olivia Kalmanson; Alexander J Ghanayem; William Sears Journal: Eur Spine J Date: 2017-11-06 Impact factor: 3.134
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Authors: Roland D Donk; Hisse Arnts; Wim I M Verhagen; Hans Groenewoud; Andre Verbeek; Ronald H M A Bartels Journal: Acta Neurochir (Wien) Date: 2017-09-08 Impact factor: 2.216