Wednesday, September 26, 2018 3:35 PM – 5:05 PM Preserving Spinal Motion: 92. A prospective, multicenter evaluation of the relationship between standing and recumbent surgical lumbar lordosis

BACKGROUND CONTEXT Lumbosacral and global spinal alignment are increasingly understood to affect health-related quality of life and long-term survivability of spinal fusion procedures. As alignment considerations in surgical decision-making continue to become more common, a reliable understanding of standing versus recumbent alignment may aid in reconciling preoperative alignment planning with intraoperative surgical decision-making. PURPOSE The purpose of this study was to compare standing lumbar lordosis with intraoperative recumbent lordosis on a variety of tables and in a variety of surgical positions. STUDY DESIGN/SETTING A prospective, multi-center, evaluation of standing to recumbent spinopelvic alignment was performed at 15 US institutions. PATIENT SAMPLE A total of 414 patients were enrolled. Patients were eligible for inclusion if they were at least 18 years of age and were undergoing spine surgery of any kind, at any number of levels between T1 and the pelvis, and who had preoperative lateral radiographs inclusive of the femoral head axis. Mean age of the patients was 61 years and 53% of patients were female. OUTCOME MEASURES Position of the patient during surgery, surgical table style used, and the use of additional positioning methods were collected and used as grouping variables in factorial analysis of variance (ANOVA) tests. METHODS Preoperative alignment measurements were made using NuVaMap (NuVasive, Inc. San Diego, CA, USA) software while intraoperative evaluations were made using NuVaMap O.R. (NuVasive, Inc.). Measurements included lumbar lordosis (LL) before and during surgery. RESULTS The lateral decubitus position was used in 170 (41%) cases, prone in 203 (49%), and supine in 41 (10%) cases. A Wilson frame was used in 55 (14%) cases while a spinal table (ie, Jackson) and common surgical bed were used in 37% (150) and 49% (196) of cases, respectively. Average standing preoperative lordosis for all patients was 48.6° which was maintained intraoperatively to 47.9° (p=.472). When examining only the table used, patients placed in Wilson frames lost an average of 10.7° of LL compared to standing, with common surgical beds and spinal tables losing 0.0° and gaining 2.4°, respectively (p CONCLUSIONS These data show that, on average, the difference between standing and intraoperative, recumbent, positioned lumbar lordosis in patients undergoing spine surgery is negligible (48.6° vs. 47.9°, respectively). Prone position on a Wilson frame, intuitively, resulted in the greatest loss of lordosis (10.7°) compared to standing, with supine position on a common surgical or Jackson table resulting in the most gained lordosis (5.7° and 4.9°, respectively). Large alignment variance seen in this study also suggests that intraoperative alignment assessment has utility in individualizing patient care based on real-time feedback. Future work will assess the relationship between preoperative standing, intraoperative recumbent, and postoperative standing alignment. From this work, since enrollment included patients undergoing any spinal procedure, not necessarily just fusions, it should not be assumed that these results correlate directly to postoperative alignment (eg, where lumbar flexion might be desired in decompressive procedures). FDA DEVICE/DRUG STATUS NuvaMap (Approved for this indication), NuvaMap OR (Approved for this indication)