Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters

Abstract

BACKGROUND CONTEXT Common indications for transforaminal lumbar interbody fusion (TLIF) include foraminal stenosis, degenerative disc disease and spondylolisthesis. Although minimally invasive surgical techniques (MIS) for TLIF have been shown to provide adequate postoperative sagittal alignment, it is unclear whether these procedures result in adequate reduction of canal compressive forces. PURPOSE Assess baseline to postoperative changes in cross-sectional canal area in patients undergoing minimally invasive transforaminal lumbar interbody fusion. STUDY DESIGN/SETTING Retrospective clinical review of a prospective surgeon-maintained MIS database. PATIENT SAMPLE A total of 16 patients undergoing MIS TLIF. OUTCOME MEASURES Spinal canal cross-sectional area, stenotic levels. METHODS Consecutive patients >18years undergoing transforaminal lumbar interbody fusion via minimally invasive surgical technique were included. Patients with preoperative lumbar MRIs and postoperative lumbar MRI or CT scans were assessed for spinal canal cross sectional area at operative interspace levels. Stenotic levels were defined as canal cross sectional area RESULTS Overall, 16 patients met inclusion criteria and underwent minimally invasive transforaminal lumbar interbody fusion. Mean patient age was 54.3±12.1years, 63% of patients were female, and mean Charlson Comorbidity Index score was 0.86±1.10. Patients presented with three primary diagnoses: herniated nucleus pulposis (36.8%), stenosis (42.1%) and spondylosis (21.1%). On average, patients underwent fusions spanning 1.69±1.13 levels, and 37.5% of patients underwent multilevel fusion. 93.7% of cases involved laminotomy, 31.3% laminectomy, 81.3% foraminotomy. Mean operative time was 349 minutes and blood loss was 389±486 ccs. From baseline to postoperative intervals, 87.5% of patients showed an increase in mean operative interspace canal cross sectional area, with the overall cohort showing significant improvement in canal cross sectional area (207.6 mm2 to 301.6 mm2, p CONCLUSIONS Following minimally invasive transforaminal lumbar interbody fusion, patients showed a significant increase in spinal canal cross sectional area. This increase in canal cross sectional area corresponded with an overall decrease in the rate of lumbar stenosis, suggesting MIS TLIF procedures have the potential to provide adequate relief of spinal canal compressive forces.