Study design: A prospective cohort study.
Objective: This study aimed to compare the outcome of cervical laminoplasty between diabetic patients and nondiabetic patients with cervical spondylotic myelopathy.
Summary of background data: A few retrospective studies have investigated the outcomes of cervical myelopathy in diabetic patients; therefore, our large-scale cohort study was designed to assess these outcomes in cervical spondylotic myelopathy.
Methods: In total, 505 consecutive patients with cervical spondylotic myelopathy (311 males, 194 females; mean age, 66.6 yr; range, 41-91 yr) who underwent double-door laminoplasty were prospectively enrolled. They were followed up for more than 12 months after surgery (mean follow-up period, 25.6 ± 12.6 mo). The patients were divided on the basis of diabetic criteria for glucose intolerance into 2 groups: the diabetic group (n = 105) and nondiabetic group (n = 400). We evaluated differences in pre- and postoperative Japanese Orthopaedic Association (JOA) scores, recovery rate, achieved JOA scores (postoperative JOA score - preoperative JOA score), and complications between both groups.
Results: The mean JOA scores in the diabetic and nondiabetic groups were 10.1 and 10.8 points before surgery and 13.1 and 13.9 points after surgery, respectively. The diabetic group showed significantly low pre- and postoperative JOA scores and low recovery rate of JOA scores compared with the nondiabetic group (47.3% vs. 53.6%, P < 0.05). However, mean achieved JOA scores in the diabetic and nondiabetic groups were 3.0 and 3.1 points respectively, with no significant difference between both groups (P = 0.343). The groups showed no significant difference in the postoperative complication rate.
Conclusion: Pre- and postoperative JOA scores and recovery rates were lower in the diabetic group than the nondiabetic group. However, the achieved JOA scores were not significantly different between both groups. Diabetic and nondiabetic patients experienced similar benefits from laminoplasty.
Level of evidence: 3.