Rim enhancement on MRI predicts long-term outcomes in extruded/migrated lumbar disc herniation managed with an...

Based on the theory of resorption of herniated nucleus pulposus (HNP), this study aimed to investigate the long-term clinical and radiological outcomes of patients with extruded/migrated LDH treated with an inflammation-preserving protocol, and to evaluate the prognostic value of the rim enhancement sign in predicting HNP resorption and clinical efficacy over 6 years.

A prospective single-arm cohort study was designed, enrolling 66 patients with extruded or migrated LDH treated at our hospital between January 2016 and September 2019, with follow-up extending to 6 years. All patients received standardized conservative treatment combined with an inflammation-preserving protocol centered on avoidance of non-steroidal anti-inflammatory drugs. Based on the presence of a high-signal rim enhancement of the herniated nucleus pulposus on pre-treatment lumbar contrast-enhanced MRI, patients were divided into a Rim Enhancement Positive group and a Rim Enhancement Negative control group. The herniation volume was dynamically measured via MRI, and the resorption rate was calculated. Clinical outcomes were comprehensively evaluated using baseline data, Japanese Orthopedic Association (JOA) scores, Oswestry Disability Index (ODI), and the positive angle of the Straight Leg Raising Test (SLRT).

All 66 patients completed the 6-year follow-up. The mean age was 35.91 ± 10.07 years, with 48 males and 18 females. No statistically significant differences were found in baseline characteristics such as age, gender, and disease duration between the two groups (P > 0.05). Statistically significant differences were found between the groups regarding herniation volume and overall resorption rate at 1 year and 3 years post-treatment (P < 0.05). The improvement rates of JOA scores, ODI, SLRT positive angle, and the absolute values of these outcomes at 6 years showed statistically significant differences between the groups (P < 0.05), while no significant differences were found for other indicators. Within all patients, comparisons of JOA scores, ODI, SLRT positive angle, and herniation volume between pre-treatment and all post-treatment time points revealed statistically significant differences (P < 0.05). Correlation analysis demonstrated a significant positive correlation between the improvement rate of JOA scores and the resorption rate (r = 0.614, P < 0.05), a significant positive correlation between the ODI improvement rate and the resorption rate (r = 0.773, P < 0.05), and a significant positive correlation between the SLRT positive angle improvement rate and the resorption rate (r = 0.360, P < 0.05). Multivariate linear regression analysis, adjusting for age, gender, symptom duration, and baseline herniation volume, revealed that baseline herniation volume was the strongest independent predictor of JOA improvement rate (B = 0.035, P < 0.001), while rim enhancement showed a trend toward independent predictive value (B = 0.156, P = 0.092). All patients showed significant clinical improvement after treatment, with no occurrences of progressive neurological deficit or cauda equina syndrome during the follow-up period.

In patients with extruded and migrated LDH managed with an inflammation-preserving protocol, favorable long-term outcomes were observed, with rim enhancement serving as a useful prognostic indicator for nucleus pulposus resorption and symptomatic improvement. However, due to the single-arm design, the specific contribution of inflammation preservation requires validation in future controlled trials.