Abstract
Introduction. The sacroiliac joint (SIJ) is a potential source of pain in the ASD population. Incidence and predictors of preoperative SIJ pain and rates of resolution with surgery in the ASD population are not well understood. Methods. A prospective, multicenter database of surgically treated ASD patients was queried for baseline SIJ pain at the preoperative assessment. SIJ pain was defined as self-reported back pain in the posterior superior iliac spine region scored >= 4 out of 10 and >= 3 of 5 positive provocative SIJ maneuvers. Demographic data, spinal alignment parameters, and health assessments were assessed using Wilcoxon and chi(2) analysis. Predictors of preoperative SIJ pain were assessed with univariate and multivariate logistic regression. Results. A total of 735 patients were included with a mean (SD) age of 61.3 (15.3) years, BMI of 27.6 (5.4), Edmonton Frailty Score (EFS) of 3.4 (2.5), and Charlson Comorbidity Index (CCI) of 1.1 (1.8). A total of 65% were female and 6% were tobacco users. A total of 411 patients had self-reported PSIS pain and 53 patients (7.2%) had preoperative SIJ pain as assessed by SIJ maneuver testing. SIJ pain was not associated with history of prior lumbosacral fusion (P=0.23). Patients with SIJ pain had higher BMI (30.0 vs. 27.4, P=0.004), preoperative pain medication usage (92.5% vs. 77.7%, P=0.02), EFS (4.6 vs. 3.3, P<0.001), and CCI (1.6 vs. 1.0, P=0.006) as well as lower L4-S1 lordosis (28.7 vs. 34.5, P=0.02) and greater L1 pelvic angle (14.5 vs. 10.8, P=0.03). After variable selection with univariate regression, multivariate logistic regression identified higher BMI (OR 1.06, P=0.033) as a significant predictor of SIJ pain at preoperative. In the patient cohort with SIJ pain at preoperative, 91.7% reported no SIJ pain at 1-year follow-up. 11/53 (20.8%) patients with baseline pain and SIJ fusion performed concurrently with ASD surgery had 100% resolution of SIJ pain in this cohort; however, there was no significant difference in pain resolution between patients with SIJ fusion and those without (P=1). Conclusion. We found a lower prevalence of preoperative SIJ pain in ASD patients than what has been historically reported, present in 7.2% of patients. Higher BMI was a predictor of preoperative SIJ pain in this population. ASD surgery led to resolution of SIJ pain in >90% of patients at 1-year follow-up.