Spontaneous resorption of disc herniations in adjacent segment after endoscopic spine surgery: Cohort study.

BACKGROUND

Although spontaneous resorption of lumbar disc herniation (LDH) has been documented in the literature, its occurrence specifically in adjacent segments following endoscopic spine surgery remains unreported. This study aimed to investigate whether spontaneous resorption occurs in adjacent segments after endoscopic discectomy and to evaluate the associated clinical and radiological outcomes.

METHODS

A cohort of 91 patients diagnosed with single-segment LDH who underwent endoscopic surgery between 2020 and 2022 was included. Patients were classified into a Herniated group (n = 46) and a Bulging group (n = 45) based on preoperative MRI findings. Clinical outcomes were assessed using the Japanese Orthopedic Association (JOA) score and Visual Analog Scale (VAS). Radiological parameters, including disc height, protrusion volume, lumbar lordosis (Cobb angle), and paraspinal muscle morphology, were measured preoperatively and at final follow-up. Logistic regression was performed to identify predictors of resorption.

RESULTS

Both groups showed significant improvements in JOA and VAS scores postoperatively (P < 0.05). At final follow-up, reductions in disc height, lumbar curvature, protrusion volume, and protrusion ratio were observed in adjacent segments. Logistic regression analysis identified age (OR = 1.290, p = 0.009), preoperative protrusion volume (OR = 4.511, p = 0.014), and preoperative lumbar lordosis (OR = 0.481, p = 0.015) as independent predictors of spontaneous resorption.

CONCLUSIONS

Spontaneous resorption of adjacent-segment LDH can occur after endoscopic surgery, particularly in younger patients with smaller protrusions and relatively preserved spinal alignment. These findings support a conservative, expectant management approach for asymptomatic or minimally symptomatic adjacent-segment protrusions, potentially reducing unnecessary surgical intervention.

LEVEL OF EVIDENCE: III.