Full-Endoscopic Lumbar Discectomy for Recurrent Lumbar Disc Herniation: A Retrospective Study with Patient-Reported Outcome Measures

INTRODUCTION: Revision surgery for recurrent lumbar disc herniation after surgical treatment is at times challenging due to epidural adhesions and scar. This study aimed to review the clinical results and safety of full-endoscopic lumbar discectomy via interlaminar (FELD-IL) and transforaminal (FELD-TF) approaches for revision surgery. METHODS: We conducted a retrospective study including 52 lumbar disc herniation revision patients (mean age, 51.8 years; male/female, 13/39), with 17 FELD-IL and 35 FELD-TF cases. Complication incidences were assessed by reviewing surgical videos and postoperative magnetic resonance images of nerve decompression outcomes. Patients' responses to Japan Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and numerical rating scales (NRS) for lumbar pain, leg pain, and leg numbness were recorded before and during follow-up. The Wilcoxon-signed rank tests were utilized to compare pre- and postoperative group variables. RESULTS: The average operation time was 33.0 min in FELD-IL and 31.7 min in FELD-TF. Seven FELD-IL cases required lamina excavation with high-speed drill bars for scar tissue dissection from the lamina. Dura injury occurred during the excavation in one case. No complication was noted in the FELD-TF group. Successful decompression of the nerve was achieved in all cases. Complete sets of JOABPEQ and NRS were obtained in 64.5% of FELD-IL and in 82.9% of FELD-TF. The mean follow-up period was 18.6 months. All the subdomain of JOABPEQ and NRS improved significantly postoperative in both groups. There was no difference regarding the improvement of scores between the procedures except NRS for lumbar pain, which was more favorable in FELD-IL. Recurrence of herniation occurred in one patient (6%) after FELD-IL and two patients (6%) after FELD-TF. CONCLUSIONS: Both FELD-IL and FELD-TF are safe and effective revision procedures for recurrent lumbar disc herniation. FELD-TF could be performed employing the same procedure as primary surgery in revisions, regardless of the previous surgical approach.