Mini-plate versus Suture-Anchor in Double-door Laminoplasty for Degenerative Cervical Myelopathy: Protocol for a Multicenter, Non-Inferiority, Randomized Controlled Trial

Abstract Background Degenerative cervical myelopathy (DCM) is a leading cause of spinal cord dysfunction. While cervical laminoplasty (LAMP) is the standard treatment, the optimal fixation technique, specifically between the conventional suture-anchor method and the modern mini-plate system, remains debated. Although mini-plates offer rigid fixation, they are associated with higher costs and even exist potential complications of lamina reclosure by screw dislodgement or hinge fracture. This study aims to verify the non-inferiority of the suture-anchor method compared to the mini-plate method in double-door LAMP. Methods This is a multicenter, open-label, non-inferiority randomized controlled trial. A total of 216 patients with DCM (cervical spondylotic myelopathy [CSM] or ossification of the posterior longitudinal ligament [OPLL]) will be recruited from three high-volume spine centers in Japan. Participants will be randomized (1:1) to undergo double-door LAMP using either mini-plates (control group) or suture-anchors (experimental treatment group). The primary endpoint is the recovery rate of the Japanese Orthopaedic Association (JOA) score at 1 year postoperatively. Secondary endpoints include operative time, blood loss, clinical assessments (EQ-5D-5L, visual analog scale [VAS], and neck disability index [NDI]), radiological outcomes (cervical spinal alignment, lamina retention rate, hinge fracture, bone union, and MRI findings), direct medical costs, and perioperative complications. Conclusions We hypothesize that the suture-anchor technique is non-inferior to the mini-plate system regarding neurological recovery and laminar stability. By rigorously comparing these techniques, this trial seeks to establish high-level evidence for a surgical strategy that maintains clinical standards while potentially reducing healthcare costs. Name of the registry Japan Registry of Clinical Trials (jRCT). Trial registry number jRCT1032250437 Registration data https://jrct.mhlw.go.jp/latest-detail/jRCT1032250437