Descriptive Analysis and Postoperative Surgical Complications of Ankylosing Spondylitis and Diffuse Idiopathic...

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.

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.

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/m² and 32.9 kg/m², respectively. Most patients lived in urban areas and in nationally disadvantaged regions, though they were relatively more advantaged within their state. Current tobacco use was reported in 21.0% of AS patients and 13.2% of DISH patients, and alcohol use was reported in approximately half of each cohort. HLA-B27 positivity was documented in 37.4% of AS patients and 1.9% of DISH patients. Among 699 patients with available data, the median number of comorbidities was three per patient; cardiovascular disease, chronic pulmonary disorders, and hypertension were common in both groups, with osteoporosis more prevalent in AS patients and diabetes more common in DISH patients. 220 patients underwent 573 orthopedic procedures, most commonly spine surgeries, particularly fusions. The median hospital length of stay was one day for AS patients and two days for DISH patients. Postoperative complications within 90 days were infrequent.

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.

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