Full endoscopic versus open discectomy for sciatica: randomised controlled non-inferiority trial

Abstract

Objective: To assess whether percutaneous transforaminal endoscopic discectomy (PTED) is non-inferior to conventional open microdiscectomy in reduction of leg pain caused by lumbar disc herniation.

Design: Multicentre randomised controlled trial with non-inferiority design.

Setting: Four hospitals in the Netherlands.

Participants: 613 patients aged 18-70 years with at least six weeks of radiating leg pain caused by lumbar disc herniation. The trial included a predetermined set of 125 patients receiving PTED who were the learning curve cases performed by surgeons who did not do PTED before the trial.

Interventions: PTED (n=179) compared with open microdiscectomy (n=309).

Main outcome measures: The primary outcome was self-reported leg pain measured by a 0-100 visual analogue scale at 12 months, assuming a non-inferiority margin of 5.0. Secondary outcomes included complications, reoperations, self-reported functional status as measured with the Oswestry Disability Index, visual analogue scale for back pain, health related quality of life, and self-perceived recovery. Outcomes were measured until one year after surgery and were longitudinally analysed according to the intention-to-treat principle. Patients belonging to the PTED learning curve were omitted from the primary analyses.

Results: At 12 months, patients who were randomised to PTED had a statistically significantly lower visual analogue scale score for leg pain (median 7.0, interquartile range 1.0-30.0) compared with patients randomised to open microdiscectomy (16.0, 2.0-53.5) (between group difference of 7.1, 95% confidence interval 2.8 to 11.3). Blood loss was less, length of hospital admission was shorter, and timing of postoperative mobilisation was earlier in the PTED group than in the open microdiscectomy group. Secondary patient reported outcomes such as the Oswestry Disability Index, visual analogue scale for back pain, health related quality of life, and self-perceived recovery, were similarly in favour of PTED. Within one year, nine (5%) in the PTED group compared with 14 (6%) in the open microdiscectomy group had repeated surgery. Per protocol analysis and sensitivity analyses including the patients of the learning curve resulted in similar outcomes to the primary analysis.

Conclusions: PTED was non-inferior to open microdiscectomy in reduction of leg pain. PTED resulted in more favourable results for self-reported leg pain, back pain, functional status, quality of life, and recovery. These differences, however, were small and may not reach clinical relevance. PTED can be considered as an effective alternative to open microdiscectomy in treating sciatica.

Trial registration: NCT02602093ClinicalTrials.gov NCT02602093.

Fig 1

Flowchart of study eligibility, enrolment, procedures, and outcomes. LHD=lumbar disc herniation;PTED=percutaneous transforaminal endoscopic discectomy

Fig 2

Median scores on visual analogue scale for leg pain, Oswestry Disability Index, visual analogue scale for back pain, visual analogue scale for quality of life, SF-36 physical component summary, and SF-36 mental component summary. PTED=percutaneous transforaminal endoscopic discectomy

Fig 3

Results of primary outcome for main and alternative analyses. Mean difference between groups is shown on visual analogue scale (VAS) for leg pain at 12 months, together with 95% confidence interval (CI). Modified intention-to-treat population included all patients randomised to percutaneous transforaminal endoscopic discectomy (PTED) or open microdiscectomy (OM) without learning curve cases. Per protocol population included all patients randomised to PTED or OM who received allocated treatment. Learning curve cases were also omitted for these analyses. Results of modified intention-to-treat population are also presented including learning curve cases. Crude analyses were adjusted for baseline and centre. Fully adjusted analysis included adjustment for baseline score, centre, age, sex, duration of complaints, smoking status, body mass index, employment status, site of disc protrusion, treatment preference of patient, and psychopathology as measured on four dimensional symptom questionnaire