Clinical Preliminary Report Of Modified Open-door Laminoplasty

Objective :To verify whether the modified open-door laminoplasty is effective in preventing postoperative axial symptom and in decompression of spinal cord in treatment for cervical spondylotic myelopathy(CSM), development spinal stenonsis and ossification of posterior longitudinal ligament (OPLL)Methods: Since March 2006 to September 2006, 41cases of cervical spondylosis myelopathy(CSM ), development spinal stenonsis and OPLL patients underwent extensive open-door laminoplasty. 18 patients who underwent modified open-door laminoplasty which intermediary compressive laminae was undergone open-door laminoplasty and both-side laminae was undergone partial laminectomy were included in this study(group A).23 patients who underwent conventional C3-7 open-door laminoplasty in the authors department were served as control(group B). Preoperative and postoperative improvement rate of Japanese Orthopedic Association (JOA)scores, the degree of axial symptom, the effect of decompression ,ranges of neck motion, cervical curvature indices were recorded and compared.Results: The average JOA improvement rate was 62.0±26.4% for group A and 62.7±19.8% for group B,There was no significant difference in JOA improvement rate between two groups. The rate of patients with evident axial symptoms was 22.2% in group A and 56.5% in group B and the difference was statistically significant(P<0.05). Loss of cervical curvature indices was2.75±2.68% in group A and 5.23±2.02% in group B, and the difference was statistically significant (P<0.01).loss of ranges of neck motion was 7.21±4.07°in group A and 13.16±6.34°in group B,significant difference was also seen (P<0.01). postoperative MRI of patient in groupA indicated sufficient expansion of the spinal cord.Conclusion :Modified open-door laminoplasty was less invasive to the posterior extensor mechanism and this new procedure is effective in preventing postoperative axial symptoms with adequate decompression of the spinal cord.