Catherine Boudreau1, Sylvine Carrondo Cottin1, Jessica Ruel-Laliberté1, David Mercier2, Nicholas Gélinas-Phaneuf2, Jérôme Paquet3,4. 1. Department of Neurosciences, CHU de Québec - Université Laval Research center, Quebec, QC, Canada. 2. Hôpital de L'Enfant-Jésus, Neurosurgery, CHU de Québec - Université Laval, 1401 18e rue, Quebec, QC, G1J1Z4, Canada. 3. Department of Neurosciences, CHU de Québec - Université Laval Research center, Quebec, QC, Canada. jerome_paquet@yahoo.ca. 4. Hôpital de L'Enfant-Jésus, Neurosurgery, CHU de Québec - Université Laval, 1401 18e rue, Quebec, QC, G1J1Z4, Canada. jerome_paquet@yahoo.ca.
Abstract
PURPOSE: Cervical sagittal alignment is correlated with myelopathy severity and used by spinal surgeons for surgical planification. Magnetic resonance imaging (MRI) is the gold standard for the evaluation of cervical myelopathy but may not be for the assessment of cervical sagittal balance compared to X-rays. The objective of this study was to assess the correlation of cervical alignment between supine MRI and standing radiographs in patients with cervical spondylotic myelopathy (CSM). METHODS: Cobb, Jackson and Harrison methods were used to measure cervical sagittal alignment on supine MRI and standing radiographs of CSM adults. Cervical alignment was divided based on Cobb angle values on lordotic (> 4°), kyphotic (< - 4°) and rectitude (- 4° to 4°). Correlations between radiographic and MRI measurements were determined. Intra- and interobserver reliability were assessed and MRI and X-Ray-measured angles were compared. RESULTS: One hundred and thirty patients with CSM were reviewed. Correlations of cervical lordosis measures between radiographs and MRI were strong using the Cobb (0.65) and Jackson (0.63) methods, and moderate using the Harrison (0.37) method. Mean cervical lordosis angle was significantly lower on supine MRI compared to standing radiographs for all methods (Cobb 11.6 Rx vs. 9.2 MRI, Jackson 14.6 vs. 11.6, Harrison 23.5 vs. 19.9). Eighteen patients (15.4%) without lordosis on supine MRI presented lordosis on standing radiographs. CONCLUSION: A substantial proportion of patients has sagittal alignment discrepancies between supine MRI and standing radiographs. Therefore, standing radiographs of the cervical spine should always be included in surgical planning of CSM patients.
PURPOSE: Cervical sagittal alignment is correlated with myelopathy severity and used by spinal surgeons for surgical planification. Magnetic resonance imaging (MRI) is the gold standard for the evaluation of cervical myelopathy but may not be for the assessment of cervical sagittal balance compared to X-rays. The objective of this study was to assess the correlation of cervical alignment between supine MRI and standing radiographs in patients with cervical spondylotic myelopathy (CSM). METHODS: Cobb, Jackson and Harrison methods were used to measure cervical sagittal alignment on supine MRI and standing radiographs of CSM adults. Cervical alignment was divided based on Cobb angle values on lordotic (> 4°), kyphotic (< - 4°) and rectitude (- 4° to 4°). Correlations between radiographic and MRI measurements were determined. Intra- and interobserver reliability were assessed and MRI and X-Ray-measured angles were compared. RESULTS: One hundred and thirty patients with CSM were reviewed. Correlations of cervical lordosis measures between radiographs and MRI were strong using the Cobb (0.65) and Jackson (0.63) methods, and moderate using the Harrison (0.37) method. Mean cervical lordosis angle was significantly lower on supine MRI compared to standing radiographs for all methods (Cobb 11.6 Rx vs. 9.2 MRI, Jackson 14.6 vs. 11.6, Harrison 23.5 vs. 19.9). Eighteen patients (15.4%) without lordosis on supine MRI presented lordosis on standing radiographs. CONCLUSION: A substantial proportion of patients has sagittal alignment discrepancies between supine MRI and standing radiographs. Therefore, standing radiographs of the cervical spine should always be included in surgical planning of CSM patients.
Authors: Jessica A Tang; Justin K Scheer; Justin S Smith; Vedat Deviren; Shay Bess; Robert A Hart; Virginie Lafage; Christopher I Shaffrey; Frank Schwab; Christopher P Ames Journal: Neurosurgery Date: 2012-09 Impact factor: 4.654