Early biochemical muscle injury and one-year clinical and imaging outcomes following microsurgical versus endoscopic lumbar discectomy: A prospective comparative study.

Background and objectives Minimally invasive spinal techniques aim to reduce tissue trauma while maintaining surgical efficacy. Comparative evidence integrating early biochemical muscle injury markers with long-term clinical and imaging outcomes remains limited. This study evaluated postoperative day 3 biochemical responses, and one-year clinical and MRI-based imaging changes between microsurgical lumbar discectomy (MLD) and percutaneous endoscopic lumbar discectomy (PELD). Methods 192 patients with single-level lumbar disc herniation (L4-L5 or L5-S1) underwent MLD (n=97) or PELD (n=95) between January 2022 and October 2024. Pain and disability were assessed using the visual analogue scale (VAS) and oswestry disability index (ODI) preoperatively and at one year. Serum creatine phosphokinase (CPK), high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 (IL-6) were measured preoperatively and on postoperative days (POD) 1 and 3. MRI was performed preoperatively and at one year to assess paraspinal muscle cross-sectional area (CSA), fatty infiltration (Goutallier grading), and disc height index. Results Both groups showed significant improvement in VAS and ODI at one year (P<0.05). PELD demonstrated lower POD 1 and 3 CPK, IL-6, and hs-CRP levels (P<0.05), and shorter operative duration (66.3±12 vs. 86±14 min). MRI followup revealed better preservation of muscle CSA and less fatty infiltration in PELD (P<0.05), with comparable disc height maintenance. Interpretation and conclusions While both MLD and PELD achieved similar one-year functional outcomes, PELD demonstrated lower early biochemical markers and superior radiological muscle preservation.