Risk factors for postoperative numbness syndrome secondary to lumbar disc herniation based on propensity score matching

Objective To investigate the risk factors for postoperative numbness syndrome secondary to lumbar disc herniation (LDH) based on propensity score matching (PSM).

Methods A retrospective analysis was conducted on the clinical data of 429 LDH patients who underwent surgical treatment. The patients were divided into numbness syndrome group (85 patients) and non-numbness syndrome group (344 patients) according to whether they developed postoperative numbness syndrome. A 1∶1 match was performed between the numbness syndrome group and the non-numbness syndrome group based on PSM, with 67 patients in each group after matching. The clinical data of the two groups before and after matching were compared, and Cox regression analysis was performed on the matched data to screen risk factors for postoperative numbness syndrome secondary to LDH.

Results The incidence of postoperative numbness syndrome in LDH patients was 19.81%(85/429). Before matching, the numbness syndrome group had a higher or longer proportion of males, age, body mass index (BMI), duration of disease, proportion of patients with L₃ to L₄ or L₄ to L₅ lesion segments, proportion of patients with grade Ⅳ to Ⅴ disc degeneration, proportion of patients with prolapsed or free-fragment herniation, operation time, proportion of patients with incomplete nucleus pulposus removal during surgery, proportion of patients with annulus fibrosus rupture, proportion of patients with a history of hyperlipidemia, proportion of patients who did not undergo postoperative rehabilitation exercises, and postoperative activity intensity scores compared to the non-numbness syndrome group (P < 0.05). After matching, the numbness syndrome group had higher or longer age, BMI, duration of disease, proportion of patients with grade Ⅳ to Ⅴ disc degeneration, proportion of patients with prolapsed or free-fragment herniation, proportion of patients with incomplete nucleus pulposus removal during surgery, proportion of patients with annulus fibrosus rupture, proportion of patients with a history of diabetes, proportion of patients who did not undergo postoperative rehabilitation exercises, and postoperative activity intensity scores compared to the non-numbness syndrome group (P < 0.05). The results of multivariate Cox regression analysis showed that high BMI, grade Ⅳ to Ⅴ disc degeneration, incomplete nucleus pulposus removal during surgery, annulus fibrosus rupture, history of diabetes, lack of postoperative rehabilitation exercises, and high postoperative activity intensity were independent risk factors for postoperative numbness syndrome secondary to LDH (HR=4.395, 7.183, 4.404, 5.633, 3.521, 4.929, 3.710, P < 0.05).

Conclusion After controlling for confounding factors based on PSM, the risk factors for postoperative numbness syndrome secondary to LDH include high BMI, grade Ⅳ to Ⅴ disc degeneration, incomplete nucleus pulposus removal during surgery, annulus fibrosus rupture, a history of diabetes, lack of postoperative rehabilitation exercises, and high postoperative activity intensity, which is helpful for clinical healthcare professionals to early identify high-risk patients with postoperative numbness syndrome secondary to LDH and provide a reference for subsequent patient treatment.