MASTERS-D: Final Results of a Prospective Multi-Center Observational Data-Monitored Study of Minimally Invasive Fusion to Treat Degenerative Lumbar Disorders

Presented at SMISS Annual Forum 2013
By Wolfgang Senker MD
With Paulo Pereira MD, David Buzek MD, Arek Kosmala MD, Ulrich Hubbe MD, Neil Manson MD, FRCSC, Wout Rosenberg , Roberto Assietti MD, Fredereic Martens MD, Khai Lam MD, Giovanni Barbanti MD, Peter Durny MD, Zvi Lidar , Kai-Michael Scheufler MD, Walter Richter MD, Pawel Sloniewski MD, Salvador Fuster MD, Vassilios Vougioukas MD, Marc Schroder MD, Jorg Franke MD,

Disclosures: Wolfgang Senker MD C; Medtronic Paulo Pereira MD B; Medtronic, David Buzek MD None, Arek Kosmala MD None, Ulrich Hubbe MD A; Medtronic, B; Medtronic, C; Medtronic, Neil Manson MD, FRCSC A; Unrestricted Research Grant, $85,000/annum, Medtronic Canada. B; Education Fees, Medtronic Canada., Wout Rosenberg None, Roberto Assietti MD B; Medtronic., Fredereic Martens MD None, Khai Lam MD None, Giovanni Barbanti MD None, Peter Durny MD None, Zvi Lidar None, Kai-Michael Scheufler MD B; Medtronic, C; Medtronic, Walter Richter MD None, Pawel Sloniewski MD B; Medtronic., Salvador Fuster MD None, Vassilios Vougioukas MD None, Marc Schroder MD None, Jorg Franke MD A; Medtronic, B; Medtronic, C; Medtronic,

Introduction: Evaluation of 1- or 2-level minimally invasive posterior lumbar interbody fusion (MILIF) for degenerative lumbar (DL) disorders in a multicenter 1-year prospective observational study (NCT01143324).

Methods: 252 patients (pts) (56% female, mean age: 54 years, mean BMI: 28, mean duration of symptoms: 29 months (m) enrolled by 19 centers in 14 countries underwent 1- (83%) or 2-level (17%) MILIF (TLIF: 95%; PLIF: 5%) for treatment of leg pain (52%), back pain (39%) or claudication (9%) due to DL pathologies, including spondylolisthesis (53%), stenosis (71%), and/or disc pathology (94%). Participating surgeons were required a minimum prestudy experience of 30 MILIF cases. 15.1% of pts had previous decompression surgery at the target level. Patient demographics, intra-operative data, complications, time to first ambulation, time to study-defined recovery, surgical duration, blood loss, fluoroscopy time and adverse events (AEs) were recorded. Outcome scores (VAS back and leg, ODI, EQ-5D) were assessed pre-op and at defined time points through 12m post-op.

Results: Available for the follow up: 249 (99%) pts at 4-week (w), and 233 (92.5%) at 12m. One-level surgery occurred at L4-5 or L5-S1 in 91%, 2-level surgery at L4-S1 in 74%. Mean surgical duration, blood loss and intra-op fluoro-time were 128 vs. 182 mins, 164 vs. 233 ml, and 115 vs. 154 secs in 1- and 2-level cases, respectively. The mean time to first ambulation was 1.3 days, and time to study-defined recovery was 3.2 days. Mean pre-op VAS back (6.2) and VAS leg (5.9) scores dropped significantly (p<.0001) to 3.1 (2.9) and 1.9 (2.5) at discharge (4 w), respectively. VAS improvement was sustained between 4w and final follow-up at 12m. Fusion rates: 90.8% fusion in 1- and 90.7% for 2-level procedures (141 and 27 pts evaluated, respectively). Pre-op ODI (45.5%) and EQ-VAS (52.9) changed to 34.5% (22.4%) and 65.4 (71.0) at 4w (12m) (p<.0001). There was a constant improvement of EQ-5D subscales and reduction of pain medication from 4w to 12m. A total of 50 AEs in 39 pts (15.5%) were attributed to surgery, approach or device (including 9 SAEs in 8 pts), out of which 3 AEs in 3 pts (1.2%) to the minimally invasive approach (including 1 SAE); no deep surgical site infections and 7 reoperations occurred.

Conclusion: This is the largest data monitored prospective multicenter observational study of MILIF to date, following routine local standard of practice and providing objective results for this procedure. MILIF demonstrated favorable clinical results with early and sustained improvement in patient reported outcomes and low major peri-operative morbidity.