General Session: MIS - Hall F
Presented by: J. Chi
J. Chi(1,2), K. Huang(1,2), M. Krag(3), P. Nunley(4), M. Bydon(5), S. Lavoie(6), SCOUT investigators
(1) Brigham and Women's Hospital, Neurosurgery, Boston, MA, United States
(2) Harvard Medical School, Neurosurgery, Boston, MA, United States
(3) University of Vermont College of Medicine, Orthopedics and Rehabilitation, South Burlington, VT, United States
(4) Louisiana State University Health Sciences Center, Orthopedic Surgery, Shreveport, LA, United States
(5) Mayo Clinic, Neurosurgery, Rochester, MN, United States
(6) Central Florida Regional Hospital, Orthopedic Surgery, Sanford, FL, United States
Introduction: Surgical options continue to evolve for patients with medically-refractory lumbar degenerative disc disease and spondylolisthesis. Current interbody fusion techniques with rigid cages are well-known to spine surgeons, but necessitate a certain degree of soft-tissue dissection and bone removal to accommodate placement of the cage. The SCOUT study is an FDA IDE trial investigating the safety and efficacy of a novel device for lumbar interbody arthrodesis. It is an expandable bone graft-containing fabric mesh that can be deployed through a delivery portal only 8mm in diameter. We report here on 12 months follow-up results.
Methods: Patients were enrolled at nine different investigational sites in a prospective, single-arm trial starting in 2015. Patients selected for the study were skeletally mature adults, ages 21 to 80, who had single-level symptomatic lumbar degenerative disc disease (levels L2-S1) requiring interbody fusion. All patients had a minimum Visual Analogue Score (VAS) of 40mm (0-100 mm scale) and a minimum Oswestry Disability Index (ODI) of 40. All patients had a BMI < 40 and had failed at least 6 months of conservative therapy. Patients with multilevel disease, previous fusion at the affected level, or greater than Grade I spondylolisthesis were excluded. All patients underwent either a MIS-TLIF or open PLIF approach (chosen based on surgeon preference), and all received supplemental pedicle screw fixation.
Results: At most recent follow-up, 84 patients had undergone surgery, with 60 completing 6-month follow-up and 29 completing 12-month follow-up. From a baseline VAS low back pain score of 73.0 ± 16.6 (Mean ± SD) and baseline ODI of 54.0 ± 12.1, there were significant improvements at both 6-months (VAS: 24.1 ± 25.7, ODI: 25.3 ± 20.4, p< 0.0001 for each) and 12-months (VAS: 19.8 ± 21.5, ODI: 18.0 ± 17.0, p< 0.0001 for each). At Twelve-month follow-up, all 29 patients (100%) demonstrated radiographic fusion, as defined by evidence of bridging bone on CT scan by two independent radiologists. Twenty of 29 patients (69%) reported "Excellent" satisfaction with their surgery and 7 (24%) reported "Good" satisfaction. There were no unanticipated adverse device-related events. Three of 88 patients had a serious adverse event related to the study, including one instance of durotomy, one instance of improper device positioning, and one instance of transient radiculopathy secondary to residual stenosis.
Conclusions: Interval clinical and radiographic results for the use of an expandable fabric mesh device for lumbar interbody arthrodesis are encouraging. These favorable results indicate the potential for such a system to provide good arthrodesis and pain relief while minimizing tissue disruption.