General Session: Endoscopic Surgery

Presented by: R. Morgenstern

Author(s):

R. Morgenstern(1), C. Morgenstern(1)

(1) Centro Médico Teknon, Barcelona, Spain

Abstract

Introduction: Interbody fusion by open discectomy is the usual treatment for degenerative disk disease but requires a relatively long recovery period. The transforaminal posterolateral approach is a well-known standard in endoscopic spine surgery that allows direct access to the disk with progressive tissue dilation, avoiding tissue and bone dissection. The aim of this study was to assess the efficacy and safety of percutaneous transforaminal interbody fusion (pTLIF) for lumbar spinal fusion. pTLIF consists of percutaneous insertion of an expandable implant with the endoscopic posterolateral approach and percutaneous posterior fixation.

Methods: Between 2009 and 2017, the pTLIF procedure was performed in 50 patients with an expandable interbody cage. Indication for surgery was degenerative disk disease with or without spondylolisthesis up to grade 2, and for revision surgery patients. Percutaneous posterior fixation comprised transpedicular screws and rods, interspinous spacer and transfacet screws depending on each case. Patient outcome was scored pre- and post-operatively with visual analogic scale (VAS), Oswestry disability index (ODI) and modified Macnab criteria. Significance between pre- and post-operative scores were analyzed with Student's paired T-test.

Results: The mean follow-up period was 33.1 (SD 20.4) months. The outcome was Excellent in 28 (56%), Good in 17 (34%), Fair in 3 (6%) and Poor in 2 (4%) cases according to Macnab criteria. The latter two cases were lost before 6 months of follow-up and consequently classified as Poor. Significant differences (p < 0.001) were found between pre-operative mean scores (pre-operative VAS back 6.9 (1.9); VAS leg 7.2 (2.3); ODI 32.1 (7.6)) and mean post-operative scores (post-operative VAS back 2.7 (1.5); VAS leg 0.4 (0.8); ODI 12.7 (6.4)). In 5 cases (10%) transient ipsilateral dysesthesia at the operated level was reported post-operatively which resolved after a median of 5 weeks with oral corticoid treatment. No major complications (dural tear, nerve injury, subsidence, pseudo-arthrosis) were reported. Median postoperative time until hospital discharge was 25 hours.

Conclusions: The pTLIF technique shows 90% of Excellent and Good post-operative results and no major complications for a long-term mean follow-up of 33 months. This shows the efficacy and safety of the pTLIF procedure for primary surgery and in revision surgery cases, as it allows bypassing posterior scar tissue from previous operations hereby reducing the risk of dural tear and nerve injury. Post-operative median time until walking (6 hours) and until hospital discharge was faster compared to standard open TLIF (25 hours vs. 6 days), probably due to the less invasive handling of the soft and bony tissues with the endoscopic posterolateral approach. In our opinion, pTLIF technique has disruptive potential as it opens the way to ambulatory fusion surgery in an outpatient clinical setting.