P50. Disc Space Preparation in Transforaminal Interbody Fusion: A Comparison of Open and Minimally Invasive Technique

BACKGROUND CONTEXT: The main determinant for arthrodesis after interbody fusion is adequate disc removal and end plate preparation. Cadaver studies have demonstrated that the graft fusion area should be significantly greater than 30% of the vertebral body area to ensure adequate bone-graft contact to prevent subsidence and obtain a secure and stable arthrodesis. More recent studies examining postoperative imaging have demonstrated that after a unilateral posterior transforaminal lumbar interbody (TLIF) approach, 56% of the end plate cross-sectional can be exposed for fusion. Early reports suggest that, although technically more demanding, TLIF utilizing minimally invasive spine techniques (MIS-TLIF) results in significantly less intraoperative blood loss and surgical morbidity without a significant change in operative time when compared with standard open TLIF. Furthermore, although these reports suggest that MIS-TLIF affords comparable surgical exposure, disc removal, end plate preparation, and placement of interbody graft, these measures have never been quantitatively compared in a cadaver model.