Surgical Treatment of Recurrent Lumbar Disc Herniation: To Fuse or Not To Fuse

Background: Optimal surgical treatment for recurrence of lumbar disc herniation (LDH) remains controversial, with options ranging from repeat microdiscectomy (MD) to instrumented fusion (IF). This study aimed to guide surgical decision-making by analyzing reoperation rates, clinical and radiographic risk factors for treatment failure, and functional outcomes following MD versus IF. Methods: Prospectively collected data from 450 patients in our outcomes database who underwent surgery for recurrent LDH from 2004 through 2023 were retrospectively analyzed. Clinical assessment included predominant symptoms, neurological deficits, and American Society of Anesthesiologists (ASA) grade. Radiographic assessment included disc height, Pfirrmann grade, facet angle, and Modic changes on magnetic resonance imaging, as well as spinopelvic parameters on standing radiographs. Patient-reported outcomes were assessed using the Core Outcome Measures Index (COMI) and achievement of the minimal clinically important change (MCIC) of ≥2.2 points. Propensity-score matching (PSM) was performed to control for confounding factors. Reoperation rates were analyzed with a minimum 5-year follow-up. Results: Of 450 patients with recurrent LDH, 316 (70.2%) underwent MD and 134 (29.8%) underwent IF. In 192 patients after PSM, IF showed nonsignificantly higher MCIC achievement (odds ratio [OR] = 1.20, 95% confidence interval [CI]: 0.66 to 2.17, p = 0.65) and lower COMI scores compared with the MD group (3.34 ± 2.89 versus 4.01 ± 2.95, p = 0.059; derived Oswestry Disability Index [ODI]: 23.8 versus 28.1). IF demonstrated significantly lower reoperation risk compared with MD (15.7% [116/316] versus 36.7% [21/34], p < 0.001). The reoperations following MD were predominantly subsequent IF (73.3%) and repeat MD (23.3%), while the reoperations after IF were predominantly adjacent segment surgery (57.1%) and hardware revision (33.3%). BMI of ≥35 kg/m 2 was a significant predictor of reoperation after MD (univariate OR = 3.63, p = 0.039), while disc height of <6 mm (OR = 1.97) and Modic type-1 changes (OR = 1.78) showed trends toward increased reoperation risk (both p < 0.10). Conclusions: Although both procedures achieved clinical improvement, IF demonstrated superior long-term durability as shown by significantly lower reoperation rates over extended follow-up. Our findings support a risk-stratified surgical selection: IF should be strongly considered in patients with BMI of ≥35 kg/m 2 and those with progressive disc degeneration, whereas MD remains appropriate for patients without these risk factors. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.