Descriptive Analysis and Postoperative Surgical Complications of Ankylosing Spondylitis and Diffuse Idiopathic Skeletal Hyperostosis Patients at a Midwest Tertiary Referral Center.

Background: Patients with ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH) are at increased risk for spinal pathology and frequently require orthopedic surgical intervention. However, region-specific data describing the demographic characteristics, socioeconomic factors, operative patterns, and short-term postoperative complications in these populations remain limited. This study aims to characterize these features among AS and DISH patients treated at a Midwest tertiary referral center. Methods: We performed a retrospective, crosssectional descriptive study of patients with ICD-documented AS or DISH treated between 2008 and 2023 at a single Midwest tertiary referral center. Demographic characteristics, comorbidities, substance use, area demographics, Area Deprivation Index (ADI), orthopedic procedures, and 90-days postoperative complications were obtained from the electronic health record. Results: Among 989 patients (AS: 776; DISH: 213), most were white and male, with median age 46 years for AS and 65 years for DISH. Insurance coverage was common in both groups. Median BMI was 27.7 kg/m Conclusion: At this center, AS and DISH patients demonstrated demographic and comorbidity profiles consistent with prior reports and experienced low short-term complication rates following orthopedic surgery. These findings provide a regional benchmark that may inform future studies evaluating long-term outcomes and healthcare disparities in these populations. Level of Evidence: IV.