Prevalence and clinical relevance of endplate junction failure in lumbar disc herniation: a post-hoc subgroup analysis of 5-year follow-up prospective data.

Abstract

This study conducted a post-hoc exploratory subgroup analysis of 5-year follow-up data from a randomized controlled trial (RCT) to clarify the prevalence and clinical relevance of endplate junction failure (EPJF) in patients with lumbar disc herniation (LDH). Patients diagnosed with LDH who underwent minimally invasive discectomy in our RCT were included. Based on MRI findings, operated discs with type 1 herniation (evidencing EPJF) were assigned to Group 1, and those with type 2 herniation (without EPJF) to Group 2. Demographic characteristics, radiological parameters, and clinical outcomes (assessed via patient-reported outcome measures [PROMs]) were compared between the two groups. A total of 135 patients (69.2%) were classified as type 1 herniation with EPJF. EPJF predominantly involved both endplates (48.1%), followed by the lower endplate junction (42.2%). Sixty discs (30.8%) with intact endplates without junction failure were classified as type 2 herniation. Both groups showed significant improvements in all PROMs at short-term (6 months) and long-term (5 years) follow-ups after surgery. Although Group 1 exhibited worse short-term Oswestry Disability Index (ODI) scores, European Quality of Life-5 Dimensions (EQ-5D) scores, and visual analog scale for back pain (VAS-back) (P < 0.05), long-term PROMs were comparable between the two groups. The 5-year cumulative symptomatic recurrence rate was significantly lower in Group 1 (4.7%) than in Group 2 (14.3%) (P = 0.031). This study reinforces evidence that EPJF is common in surgical LDH patients. While EPJF negatively affects short-term clinical outcomes, long-term outcomes are satisfactory with a lower symptomatic recurrence rate. This trial was registered at ClinicalTrials.gov on November 14, 2013 (registration number: NCT01997086; https://clinicaltrials.gov/ct2/show/NCT01997086).