Clinical and radiography results of mini-plate fixation compared to suture suspensory fixation in cervical laminoplasty: A five-year follow-up study

Abstract

Objectives: Lamina closure is the most common reason for failure of unilateral open-door laminoplasty. Mini-plate fixation was designed to solve such problem. We assessed the clinical outcomes and radiography results of mini-plate fixation by comparing it with suture suspension fixation.

Patients and methods: This prospective study enrolled 57 patients with multi-segment cervical spondylotic myelopathy between January 2008 and March 2010. Thirty-four patients underwent laminoplasty with mini-plate fixation (mini-plate group) whereas 23 patients underwent laminoplasty with suture suspension fixation (suture group). The neurological function was measured with the Japanese Orthopedic Association (JOA) score. Cervical range of motion (ROM), C2-7 angle, and the spinal canal expansive parameters (anteroposterior diameter, Pavlov's ratio, cross-sectional area, and open angles) were evaluated.

Results: The mean follow-up time was 64 (60-82) months. There were no significant differences in preoperative JOA scores (p=0.191), postoperative JOA scores (p=0.700), preoperative cervical ROM (p=0.315) and preoperative C2-7 angle (p=0.074) between the two groups. Both groups had significant postoperative JOA improvement (p<0.05). The mini-plate group had larger cervical ROM (p=0.041) and C2-7 angle (p=0.040) than the suture group at the final follow-up. Both groups showed significant improvement in the spinal canal expansive parameters immediately after the surgery. In the suture group, the parameters, such as anteroposterior diameter, Pavlov's ratio, cross-sectional area, and open angles, decreased along with time, mainly within the first 6 months following the operation. In the mini-plate group, these parameters remained unchanged. The spinal canal expansive parameters between the 2 groups were not significantly different immediately following the operation, but were significantly different at the final follow-up (p<0.05). Three patients in the suture group displayed neurological deterioration due to lamina reclosure.

Conclusions: Laminoplasty by mini-plate fixation preserved more cervical ROM and better cervical alignment, maintained cervical spine canal expansive stability and effectively avoided lamina reclosure for a long-term follow-up.

Keywords: Cervical laminoplasty; Five-year follow-up; Mini-plate; Spinal canal expansive; Suture suspensory.