Analysis of Chronic Low Back Pain Caused by Lumbar Microinstability After Percutaneous Endoscopic Transforaminal Discectomy: A Retrospective Study.

Objective: Chronic low back pain (CLBP) after percutaneous endoscopic transforaminal discectomy (PTED) surgery may be caused by preoperative lumbar microinstability (MI). However, there is a paucity of research on the relationship between lumbar microinstability and chronic low back pain. The purpose of this article is to assess the preoperative radiographic characteristics of patients and evaluate the effects of lumbar microinstability on patient-reported outcomes among single-level lumbar disc herniation (LDH) patients who underwent PTED. Methods: This study retrospectively reviewed the radiographic characteristics of a consecutive series of 127 patients with low back pain and leg pain caused by single-level LDH underwent PTED from August 2018 to March 2021. They were divided into three groups according to the radiographic parameters: the stable group (Group S), the dysfunctional group (Group D), and the microinstability group (Group M). The visual analogue scale (VAS) scores for leg and low back pain and Oswestry Disability Index (ODI) were evaluated preoperatively and postoperatively. Logistic regression analysis was used to identify independent risk factors for CLBP. Results: Compared with Group D and Group S, Group M had the highest ODI scores (P < 0.01) and VAS scores (low back pain) (P < 0.01) after 1 year, while there were no significant differences in the VAS scores for leg pain at different time points after surgery (P > 0.05). In addition, the logistic regression analysis results regarding CLBP revealed that muscle fatty degeneration on MRI (95% CI, 1.20-8.51, P = 0.02), and facet tropism (95% CI, 1.39 -11.37, P = 0.01) may be independent risk factors. Conclusion: Patients with lumbar microinstability may have CLBP after PTED, so patients with lumbar microinstability may need to take internal fixation surgery to solve their symptoms.