Wednesday, September 26, 2018 3:35 PM – 5:05 PM Preserving Spinal Motion: 91. Interlaminar stabilization versus PLF in the ≤ 65 year-old patient: five-year follow-up

BACKGROUND CONTEXT After conservative treatment has failed, surgical intervention for symptomatic lumbar spinal stenosis (LSS) is common. However, LSS is rarely a discreet issue and often presents with spondylolisthesis, deformity, or other degenerative changes. Although decompression surgery is considered the standard treatment, trends indicate spine fusion surgery has disproportionately increased despite it being the more invasive approach. Interlaminar stabilization (ILS) is a less invasive alternative to fusion that is non-terminal and motion preserving. PURPOSE The purpose of this study was to compare the efficacy of decompression plus ILS (D+ILS) to decompression plus posterolateral fusion (D+PLF) in patients aged ≤ 65 years with LSS with or without grade 1 spondylolisthesis. STUDY DESIGN/SETTING Cohort analysis of a large, prospective, multi-centered, and randomized controlled Investigational Device Exemption (IDE) trial comparing ILS and decompression to posterolateral fusion with bilateral pedicle screw instrumentation. PATIENT SAMPLE A total of 181 patients from 21 US sites who underwent decompression with ILS or decompression with posterolateral spinal fusion. OUTCOME MEASURES The primary outcome was overall composite clinical success (CCS) as determined by: Oswestry Disability Index (ODI) scores, incidence of postoperative epidural injections and/or reoperations, incidence of device-related complications, and persistent or progressive neurological deficit. Secondary outcomes included patient satisfaction as measured by Visual Analog Scale (VAS) for back and worse leg pain, and Zurich Claudication Questionnaire (ZCQ) scores. Narcotic usage data and radiographic assessment of changes in postoperative posterior disc height and foraminal height were also evaluated. METHODS A cohort from the original multi-center, randomized controlled IDE clinical trial was examined with 5-year follow-up. The cohort was randomized in a 2:1 fashion with 181 patients in total, 131 in the D+ILS (coflex, Paradigm Spine, New York, NY, USA) group and 50 in the D+PLF group. Data including the length of hospital stay (LOS), estimated blood loss (EBL), and operative time were recorded. Pain management surveys and patient-reported outcomes including Oswestry Disability Index (ODI), Short Form Surveys (SF-12), Zurich Claudication Questionnaire (ZCQ), and Visual Analog Scale (VAS) for back and leg pain were completed preoperatively and out to 60 months postoperatively. Composite clinical success (CCS) was defined as a ≥15 point improvement of ODI plus the absence of reoperations, neurological deficits, and major device-related complications. RESULTS Patient follow-up at 60 months for the D+ILS group and D+PLF groups were 88.2% and 86.7% respectively. Mean length of hospital stay was 1.79 days in the D+ILS group and 3.06 days in the D+PLF group (p CONCLUSIONS At 5-year follow-up, D+ILS has been shown to be a durable and efficacious treatment option in a younger spinal stenosis population with or without grade 1 spondylolisthesis. Decompression + ILS surgery is significantly less invasive for the patient as measured by shorter operative times, decreased blood loss, and shorter length of stay. As hospital costs are of growing concern, these substantial differences should be strongly considered. As a cohort of a non-inferiority study design, patient-reported outcomes showed no differences between the groups. However, in this younger and more physically active patient population, a safe and effective non-terminal surgery should be considered before more invasive fusion surgery. FDA DEVICE/DRUG STATUS Coflex, Paradigm Spine, New York, NY (Approved for this indication)