167. Combined thoracic anterior and lumbar posterior tethering vs anterior vertebral body tethering: Outcomes in skeletally immature idiopathic scoliosis

BACKGROUND CONTEXT There is a dearth of literature on outcomes of fusionless tethering for the correction of skeletally immature idiopathic scoliosis of the thoracolumbar spine. While anterior vertebral body tethering (AVBT) is most commonly performed, combined thoracic anterior and lumbar posterior tethering (TALPT) may offer less perioperative morbidity. PURPOSE The purpose of this study is to compare the perioperative outcomes of AVBT with TALPT in skeletally immature patients with idiopathic scoliosis. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Skeletally immature patients with Lenke 5 or 6 curves of at least 40° with at least two-year follow-up who underwent AVBT or TALPT from 2014-2018 were included. OUTCOME MEASURES The primary outcome is revision. Secondary outcomes include procedure duration, estimated blood loss (EBL), length of stay (LOS), total postoperative opioid morphine equivalent (OME), foley duration, days to solid food, direct cost and 30-day readmission. Methods In this IRB-approved retrospective cohort study, AVBT and TALPT were compared with respect to primary and secondary outcome measures. AVBT was performed lateral decubitus through an open, muscle-sparing approach. TALPT patients underwent a single-stage anterior tethering for the thoracic curve and unilateral posterior tethering on the convexity of the lumbar curve. Results Of 48 enrolled patients, 6 (12.5%) underwent TALPT while 42 (87.5%) underwent AVBT. TALPT and AVBT patients had no difference in revision rate at two-years postoperatively (33% vs 36%, p=0.90). TALPT patients had increased direct cost in USD ($68,365±$17,863 vs $42,157.10±$14,459, p 0.05). Conclusions Skeletally immature idiopathic scoliosis patients who undergo TALPT have equivalent two-year revision rates and perioperative outcome compared to AVBT patients. However, TALPT had significantly increased cost and procedure time. Future research into outcomes of TALPT is warranted. FDA DEVICE/DRUG STATUS Zimmer Spinal Tether (Not approved for this indication)