51. Upper thoracic fusion does not impact physical function greater for younger vs older ASD patients undergoing long fusion to the pelvis

BACKGROUND CONTEXT Surgeons may preferentially limit fusion levels for younger vs older ASD patients to maintain motion segments and optimize postoperative function. Few data exist comparing the functional impact of upper thoracic (UT) vs thoracolumbar (TL) upper instrumented vertebra (UIV) in younger vs older ASD patients undergoing long fusion to the pelvis. PURPOSE Evaluate patient reported functional impact of UT vs TL UIV in younger vs older ASD patients undergoing long fusion to the pelvis. STUDY DESIGN/SETTING Propensity score matched (PSM) analysis of ASD patients prospectively enrolled into a multicenter study. PATIENT SAMPLE Surgically treated ASD patients prospectively enrolled into multicenter study. OUTCOME MEASURES Numeric rating scale (NRS) back and leg pain, Scoliosis Research Society-22r questionnaire (SRS-22r), Short Form-36v2 questionnaire (SF-36), Oswestry Disability Index (ODI), estimated blood loss, duration of hospital stay, postoperative complications, revision spine surgery. METHODS Surgically treated ASD patients prospectively enrolled into a multicenter ASD study were divided into 2 age groups (younger= 65 years) and separated according to UIV (TL= L2-T7; UT= T6-T1). Study inclusion criteria; 1) surgery for Lumbar (L), Sagittal (S), or Mixed (M) deformities (as per SRS-Schwab ASD classification), 2) fusion to the pelvis, 3) minimum 5 levels fused, and 4) minimum 2 year postop follow up. Surgery for double major or thoracic scoliosis were excluded. PSM was used to match preop patient demographics, scoliosis, and sagittal spinopelvic parameters including PI-LL, TK, SVS, and TPA. Surgical data evaluated and impact of UIV upon patient reported functional outcomes compared for UT vs TL for younger vs older. RESULTS From 2008-2018, 435 of 717 eligible surgically treated patients were evaluated; younger (n=193; mean age 57.6 years) and older (n=242; mean age 72.3 years), mean levels fused UT=17.4, TL=10.7 (p 0.05). Surgical blood loss, duration of SICU and hospital stay was greater for UT vs TL in younger and older (p 0.05). CONCLUSIONS Younger ASD patients fused to the pelvis do not report more physical restrictions for UT vs TL UIV compared to older ASD patients, however blood loss, SICU and hospital stay and complications were greater for UT vs TL in younger and older cohorts. When deciding upon UIV for ASD patients, the minimal impact of UT vs TL UIV upon patient reported outcomes must be offset by cognizance of a longer hospital stay and potential for greater postoperative complications for UT fusions especially in older patients. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.