Different decompressions and internal fixations for treating multilevel cervical spondylotic myelopathy: Effect of magnetic resonance image on measuring the sagittal diameter of dural sac and evaluating the recovery rate

Hu Zhao-hui; Li Bing; Li Long; Li Kang-hua; Chen Lei

doi:10.3321/j.issn:1673-8225.2007.25.008

Abstract：BACKGROUND: Compression occurs in several horizontal spinal cords of patients with multilevel cervical spondylotic myelopathy (CSM), especially compression is attacked on both ends of spinal cord. Therefore, there are so many choices of approach and way for operation. However, which approach and way have good effects and few complications is still controversial up to now.OBJECTIVE: To observe the therapeutic effect of anterior multilevel decompression and internal fixation on multilevel CSM and compare with posterior mono-open-door vertebral canal expanding laminoplasty.DESIGN: Contrast analysis.SETTING: Department of Orthopaedics, Xiangya Hospital of South China University; Department of Orthopaedics, People's Hospital of Liuzhou.PARTICIPANTS: A total of 68 patients with multilevel CSM were selected from the Department of Orthopaedics, Xiangya Hospital of South China University from January 2000 to June 2005. All patients were divided into anterior approach surgery group (n =33) and posterior approach surgery group (n =35). Baseline data between the two groups were comparable.METHODS:①Anterior approach surgery group: All 33 patients received bone-transplanting and internal fixation through cervical spine. Among them, auto-iliac bone-graft was transplanted into 17 cases, Cage auto-bone graft combining with allogenic bone was transplanted into 11 cases, and titan-net and auto-bone combining with allogenic bone was transplanted into 5 cases. In addition, long segments were dealt with internal fixation of anterior cervical spine locking plate (CSLP). Among them, 12 cases used Orion plate, 13 cased used Zephir palte, and 8 cases used Codman plate. ②Posterior approach surgery group: Fifteen patients received total laminectomy for decompression and other twenty patients received mono-open-door vertebral canal expanding laminoplasty. After laminoplasty, all patients received negative pressure and neck support fixation for three months.MAIN OUTCOME MEASURES: ①Scores were measured based on JOA evaluating system before and after laminoplasty to calculate recovery rate. The scores of JOA ranged from 0 to 17. The higher the scores were, the milder the spinal cord damage was. ② Magnetic resonance image (MRI) was used to measure and calculate the sagittal diameter of dural sac.RESULTS: A total of 68 patients were involved in the final analysis. ①Mean operative time and bleeding volume were respectively shorter and less in the posterior approach surgery group than those in the anterior approach surgery group (P＜0.05). ②Recovery rates were higher in the anterior approach surgery group than those in the posterior approach surgery group [(58.28±7.16)%, (42.71±5.85)%; (45.64±6.56)%, (37.65±5.75)%; P＜0.05].③Follow up lasted for more than 6 months. Fusion rate in the anterior approach surgery group was 100%, and mean fusion time was 4.6 months. Mobilization and breakage of plate and screw were not observed during the laminectomy.CONCLUSION: The posterior approach surgery is simple and spends a short-term duration, but the effect of posterior approach surgery is inferior to anterior approach decompression.