Risk factors and treatment strategy for adjacent segment diseases after anterior cervical decompression and fusion

Abstract

Objective To investigate the risk factors and treatment strategy in treating adjacent segment diseases (ASD) after anterior cervical decompression and fusion.Methods Fourteen patients with ASD after anterior cervical decompression and fusion from December 2005 to August 2012 were analyzed.The overall curvature of the cervical spine,local curvature of surgical segments,and the distances between the plate and the upper and lower intervertebral space were measured and analyzed.10 males and 4 females,age at initial surgery was 36 to 68 years old,the mean was 52.0±11.0 years old.The secondary surgery was taken,according to the number of involved segments and other factors.Anterior decompression and fusion and internal fixation was taken to patients who segment number ≤2 without severe ossification of posterior longitudinal ligament or ossification of the ligamentum flava; posterior decompression and laminoplasty was conducted in patients whose segment number ≥3,but not accompanied with significant kyphosis,instability and serious ossification of the ligamentum flava; and posterior laminectomy and fusion was performed in patients with significant kyphosis,instability and not suitable for anterior decompression due to technical reasons,as well as patients with serious ossification of the ligamentum flava.Results The average time of occurrence of ASD after the initial surgery was 9.3±4.4 years,and the average age of reoperation was 61.3±12.4 years old.The overall curvature of the cervical spine,surgical segment local curvature after the initial surgical procedure were 12.4°± 10.8 o,1.5o±6.8o,respectively; and the distances between the plate and the upper and lower interyertebral space were:0.9± 1.8 mm,3.8±3.2 mm.The secondary surgeries were taken as follows:9 cases anterior decompression and fusion and internal fixation,3 cases posterior decompression and laminoplasty,and 2 cases posterior laminectomy and fusion.All 14 patients were followed up 30.4± 17.8 months,and the average improvement rate of Japanese Orthopaedic Association scores at the last follow up was 73.9％±9.7％.Conclusion The smaller distance between the plate and neighboring intervertebral space,and poorer local curvature of surgical segments might be the risk factors for ASD after anterior cervicad decompression and fusion.The appropriate secondary surgery was taken after comprehensive analysis of the number of adjacent segments,compression factors,cervical curvature and other factors. Key words: Cervical vertebrae; Spinal fusion; Postoperative complications