Abstract: Open-door laminoplasty for spondylotic myelopathy has been documented for over 30 years.This method can decompress the vertebral canal and improve the nerve function satisfactorily through the clinical studies.However,radicular and axial symptoms including neck malaise and stiffness and other problems occur frequently after close-door operation.We used a modified open-door laminoplasty to treat the spondylotic myelopathy,and had achieved satisfactory results.Objective Our purpose is to assess the effects of the modified open-door laminoplasty for spondylotic myelopathy.Methods From October 2003 to January 2006,78 patients had been treated with open-door laminoplasty and 43 cases had been followed-up.The operation were carried out in prone position and under general anesthesia.Titan lag screw had been wrung in the lateral mass of C3,C5,C6 and C7 after the door was opened,No.10 silk nesis had been used to sew the Titan lag screw and the spinous process.The vertebral plate was hang with lateral mass screw to keep the door opening.The end of extensor was repaired by PDS-Ⅱadsorbable suture on C2 processus spinosus.Pre-and post-operative JOA scores had been used to evaluate the clinical results.The axial symptoms and radicular symptoms were observed to evaluate the results,using the SPSS 11.5 software to process the data.Results In the 43 cases of cervical spondylotic myelopathy,mean follow up was 22 months(12 to 36 months).The average pre-OP JOA score was 7.2±3.2 and post-OP JOA score was 14.1±2.1;the improvement rate was 73.1±16.7 percent.Sagital diamete of vertebral canal of pre-operation was(11.8±2.2)mm,the average open-door extent was(16.7±4.9)mm,the range of motion of pre-operation was 44.7±5.1 degree,the range of motion of post-operation was 34.2±4.4 degree,the total range of motion had reduced 17 percent after operation(the highest was up to 71 percent according to the literature),the incidence of axial symptoms was 17.83 percent and the incidence of radicular symptoms was 7 percent.According to Odom's scoring system.Twenty-four patients had excellent result,19 good,3 fair.Conclusion The modified open-door laminoplasty for spondylotic myelopathy can enlarge the average open-door extent,increase the range of motion,reduce the radicular and axial symptoms and neck malaise when compared with the traditional method.The modified open-door laminoplasty has achived satisfactory result.However,it problems still remain.Some patients feel neck stiffness after operation in those.Some symptoms have not disappeared completely,especially patients with prolonged course,elder age and disability of bladder or lower limb function.

Key words: cervical spondylosis, laminoplasty, clinical result