P32. Assessing endocrine abnormalities as risk factors for Pseudarthrosis after adult spinal deformity (ASD) surgery at minimum 2 year follow-up

Abstract

<h3>BACKGROUND CONTEXT</h3> Amongst spine surgeons, pseudarthrosis remains a leading cause of revision surgery. Basic science literature has found endocrine abnormalities to adversely impact bone fusion and healing. Given lack of studies within ASD literature, we evaluated the impact of hypothyroidism and hyperlipidemia on pseudarthrosis, while controlling for potential risk factors. <h3>PURPOSE</h3> We sought to evaluate the association between preoperative hypothyroidism and hyperlipidemia on the development of postoperative pseudarthorsis, in the setting of ASD surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of single-institute database. <h3>PATIENT SAMPLE</h3> A total of 180 ASD patients undergoing spinal fusion of 4 or more levels, between 2008 and 2018. <h3>OUTCOME MEASURES</h3> Development of pseudarthrosis, determined surgically. <h3>METHODS</h3> A retrospective review of a single-institution database. Inclusion criteria was (1) ASD patients 18 and older, (2) undergoing 4 or more levels of arthrodesis with (3) minimum 2-year follow-up. Primary outcome variable was pseudarthrosis which required a reoperation. Primary predictor variable was preoperative diagnosis of hypothyroidism or hyperlipidemia (HLD). Additional variables collected included patient demographics, surgical parameters (levels fused, three column osteotomy, iliac fixation, and revision surgery), and Charlson Comorbidity Index. Multivariable logistic regression analysis was used to determine risk factors for pseudarthrosis, after controlling for patient characteristics (Age, Gender, CCI, smoking status) and surgical characteristics (BMP use). <h3>RESULTS</h3> A total of 180 patients met inclusion criteria, 147 (82%) were women with a mean ± standard deviation of age was 61 ±12 years. Mean levels fused was 9.6 ± 3.8. At a mean follow-up of 4.33 years (Range 2-10 years), 31 (17%) patients developed pseudarthrosis, which required revision surgery. On multivariable logistic regression, risk factors for pseudarthrosis included preoperative hypothyroidism (aOR:3.20, 95% CI: 1.09, 9.39, P=0.03) and HLD (aOR:2.95, 95% CI: 1.08, 8.08, P=0.04). Patient demographics and operative variables were not associated with postoperative pseudarthrosis. <h3>CONCLUSIONS</h3> We found that preoperative diagnosis of hypothyroidism and HLD were independent associated with postoperative pseudarthrosis. This study has direct clinical implications by highlighting the importance of screening for endocrine abnormalities. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.