Scientific award winning paper 2025 of the swiss society of spinal surgery: The impact of Modic changes in recurrent lumbar disc herniation: Persistent Modic type 1 changes represent a high-risk phenotype for early re-herniation.

BACKGROUND

Surgical strategies for recurrent lumbar disc herniation (ReLDH) range from repeat microdiscectomy (MD) to instrumented fusion (IF). Identifying predictive factors for surgical treatment could improve patient selection and outcomes. The primary objective of this study was to investigate the impact of Modic changes (MC) on clinical outcomes, radiological progression, and re-operation rates in ReLDH. The secondary objective was to compare outcomes between MD and IF stratified by MC patterns to determine whether MC assessment can guide surgical decision-making.

METHODS

This is a pre-planned subgroup analysis from a single-center retrospective cohort study of prospectively collected registry data. We analyzed 450 consecutive patients who underwent surgery for ReLDH (MD: n = 316, IF: n = 134) from 2004 to 2024. Radiological assessment included T1-and T2-weighted magnetic resonance imaging (MRI) sequences analyzing presence and type of MC, disc height, and Pfirrmann grade of the affected segment, and spinopelvic parameters on standing radiographs. Persistent MC were defined as maintaining the same Modic type at both index and revision surgery (e.g., Type 1→Type 1). Patient-reported outcome was assessed using the Core Outcome Measures Index (COMI) and achievement of Minimal Clinical Important Change (MCIC ≥2.2 points) up to 5 years postoperatively. Re-operation rates, time to re-operation, and rates of subsequent re-revision surgery were analyzed for both surgical groups, with at least 5 years of follow-up.

RESULTS

Patients with persistent MC Type 1 (n = 64; MD: 41, IF:23) demonstrated the shortest median time to revision (0.58 years) compared to no MC (1.03 years, p = 0.012). Persistent MC Type 1 demonstrated the highest re-revision rate among all MC patterns following MD (48.8%), which was dramatically reduced with IF (13.0%, p < 0.05), representing a 3.7-fold risk reduction. Overall re-revision rates were 36.7% for MD versus 15.7% for IF (p < 0.001). Persistent MC Type 1 pattern showed accelerated disc degeneration with progression to Pfirrmann grade 5 in 29.7% (vs 5.8% in no MC, p < 0.001) and severe disc height loss (>30% height loss) in 20.3%. While COMI outcomes showed no significant differences between surgical approaches at any timepoint, IF demonstrated numerically greater improvement at 2 years (5.3 vs 3.5 points, p = 0.692; derived ODI: 33.1 vs. 25.9). MCIC achievement in persistent MC Type 1 patients showed no significant differences at any time point: 3 months (65.0% IF vs 47.8% MD), 1 year (63.2% IF vs 64.7% MD), 2 years (76.9% IF vs 70.6% MD), and 5 years (66.7% IF vs 66.7% MD).

CONCLUSION

Persistent Type 1 MC represent a distinct high-risk phenotype in ReLDH characterized by early recurrence, elevated re-revision rates, and accelerated segmental degeneration, compared to other MC types. The 3.7-fold reduction in re-revision rates and superior functional outcomes with IF provide compelling evidence, that warrant consideration in surgical decision-making.