Risk factors of reoperations after percutaneous endoscopic lumbar discectomy for lumbar disc herniation

English Keywords:Lumbar disc herniation  Percutaneous endoscopic lumbar discectomy  Reoperation  Risk factors

English Abstract:

  【Abstract】 Objectives: To determine the risk factors of reoperation for lumbar disc herniation（LDH） after percutaneous endoscopic lumbar discectomy(PELD). Methods: 476 patients who underwent PELD for single-level LDH between July 2014 to June 2017 were enrolled in this study. All patients were divided into reoperation group and control group based on whether they accepted reoperations. The cumulative reoperation rate was evaluated by using Kaplan-Meier analysis. Surgical findings [age, sex, body mass index(BMI), smoking, diabetes, course of disease, operation time and surgeons] and clinical parameters (herniation type, Pfirrmann disc degeneration grade, Modic endplate changes, disc height, disk calcification, lumbar instability) were collected and retrospectively assessed. The above factors were compared between the two groups by using unpaired t test and Chi-Square test. Variables that were significant at the P<0.1 level were candidates for inclusion in the final multivariable Logistic regression analysis. Results: The mean interval between primary and revision surgeries was 12.2±10.3 months（1-48 months） and 63.9% of reoperations were performed within 1 year. Cumulative overall reoperation rate gradually increased to 11.5% in 4 years. Univariate analysis found that age ≥50, BMI≥24kg/m2, lumbar instability and unherniated disc calcification were statistically significant(P<0.1). However, the differences in gender, smoking, diabetes, surgeons herniation type, Modic endplate changes and disc height between the two groups were not significant(P>0.1). The Logistic regression analysis demonstrated BMI≥24kg/m2(OR=2.41, 95%CI 1.183-4.907, P<0.05) was a risk factor for reoperations after PELD while unherniated disc calcification(OR=0.33, 95%CI 0.138-0.852, P<0.05) was a protective factor. Conclusions: The reoperations after PELD for single level LDH mostly occurr within one year. BMI≥24kg/m2 is the risk factor for reoperations after PELD to treat LDH while unherniated disc calcification may be a protective factor.