Impact of symptom duration on the effectiveness of intradiscal condoliase injection for lumbar disc herniation: A multicenter retrospective study.

Abstract

Intradiscal condoliase injection has become a minimally invasive therapeutic option for lumbar disc herniation (LDH) in Japan. However, the influence of symptom duration on its clinical and radiological effectiveness has not been fully established. This multicenter retrospective study included 228 patients treated with either intradiscal condoliase injection (CD group, n = 180) or microendoscopic discectomy (MED group, n = 48) across nine academic institutions. Patients were stratified into four groups by symptom duration: ≤2 months, 3-5 months, 6-11 months, and ≥12 months. Clinical outcomes included changes in Numerical Rating Scale (NRS) scores for back and leg pain, responder rate (≥50 % leg pain reduction), and MRI-based disc resorption rate. Statistical analyses were adjusted for age, sex, and herniation level. In the CD group, longer symptom duration was associated with reduced treatment effectiveness. At 3-6 months, duration-dependent differences were modest; adjusted improvement showed no significant trend, while only the back pain responder rate decreased with longer duration (p for trend = 0.04). At 12 months, leg pain improvement showed a non-significant downward trend (p for trend = 0.11), whereas the responder rate declined from 84.6 % to 62.5 % (p for trend = 0.03), and the resorption rate dropped from 42.3 % ± 23.5 %-23.9 % ± 24.3 % (p for trend <0.01). In contrast, the MED group showed consistent outcomes regardless of symptom duration. Pfirrmann grades did not differ significantly across groups. Longer symptom duration was associated with reduced clinical and radiologic response to intradiscal condoliase injection, with duration-dependent effects becoming more evident at 12 months than at 3-6 months. Early intervention-ideally within 6-12 months of symptom onset-may maximize therapeutic benefit. These findings support a time-sensitive approach to chemonucleolytic treatment for LDH.