Minimum of Two-Year Follow-up After Percutaneous Endoscopic Transforaminal Discectomy on Lumbar Disc Herniation: Clinical and Radiographic Outcomes

Abstract Background Percutaneous endoscopic transforaminal discectomy (PETD) is a widely-used minimally invasive technique in treating lumbar disc herniation (LDH), our aim was to investigate the long-term effect of PETD on clinical outcomes and magnetic resonance imaging (MRI) characteristics of LDH patients. Methods This is a retrospective case series to assess patients who underwent single level PETD from January 2015 to June 2019 with a minimum follow-up of 2 years. Clinical outcomes included numeric rating scale (NRS), Oswestry Disability Index (ODI) and adverse events. Radiographic parameters included sagittal spine geometry, characteristics of protrusion, and degeneration grading of intervertebral disc and facet joint. Sensitivity analysis and risk factor analysis were also performed. Results Thirty-eight patients (43.16 ± 13.32 years; M: F = 20: 18) were assessed. During the follow-up period (33.47±12.53 months), the mean disc height decreased from 10.27 ± 1.92 mm to 8.95 ± 1.74 mm (P=0.000), and lumbar lordosis increased from 31.31 ± 8.63° to 35.07 ± 8.07° (P=0.002). The size of protrusion significantly decreased after PETD (P=0.000). Disc degeneration grading was generally higher at last follow-up compared with baseline (p=0.002). Compared with baseline, significant improvements were observed on NRS and ODI at 3-months follow-up and the last follow-up. On risk factor analysis, facet tropism was correlated with radiographic recurrence of disc herniation (OR=6.00 [95% confidential interval (CI)1.176-30.624], p=0.031). Conclusions This study demonstrates that at long-term follow-up, despite the good clinical results, the PETD resulted in significant aggravation of intervertebral disc degeneration.