Characteristics of diabetes associated with poor improvements in clinical outcomes after lumbar spine surgery.

Abstract

Retrospective review. Evaluation of the impact of diabetes on lumbar spine surgery. Characteristics of diabetes that increase the risk of postoperative complications and poor surgical outcomes after lumbar spine surgery remain unclear. The demographic and clinical data of diabetic and nondiabetic patients, 50 years or older, undergoing lumbar spine surgery were reviewed. Japanese Orthopaedic Association and visual analogue scale scores for low back pain, leg pain, and numbness were assessed as perioperative outcomes. Analysis of covariance was used for comparison of perioperative outcomes to adjust for differences between the groups, and a proportional odds model was used to compute the odds ratio of poor improvement in each outcome. Forty-one patients with diabetes were compared with 124 patients without diabetes. Visual analogue scale scores of final low back pain was higher for patients with than without diabetes (29.3 vs. 17.9, P = 0.013). Complications were similar in patients with and without diabetes except for nonunion after fusion surgery (20% vs. 3%, P = 0.095). When stratified by surgical procedure, final low back pain was significantly higher for patients with diabetes who underwent fusion surgery (39.1 vs. 17.4, P = 0.001). Patients with glycosylated hemoglobin of 6.5% or more displayed a 2-fold increase only in the odds ratio (OR) of poor improvement of low back pain (OR = 2.37; 95% confidence interval [CI], 0.99-5.70). Patients having diabetes for 20 years or more were more likely to experience poor improvement of low back pain and leg numbness (OR = 4.95; 95% CI, 1.69-14.5 and OR = 2.80; 95% CI, 0.98-7.94, respectively). Insulin use was associated with an increased OR for poor improvement of leg numbness (OR = 4.49; 95% CI, 1.24-16.3). Longstanding diabetes, poor glycemic control, and insulin use might be associated with poor postoperative improvement.