Surgical invasiveness, reoperation, and preoperative depression are predictive of super-utilization in adult spinal deformity surgery.

Abstract

Purpose: A subset of adult spinal deformity (ASD) patients undergoing corrective surgery receive a disproportionate level of medical resources and incur greater costs. We examined the characteristics of such super-utilizers of health care resources among ASD patients.

Methods: This prospective, multicenter study analyzed data from ASD patients with > 4 levels of spinal fusion and a minimum 2-year follow-up. Index and total episode-of-care (EOC) costs in 2022 US dollars were calculated using average itemized direct costs obtained from administrative hospital records. Patients with total 2-year EOC cost > 90th percentile were considered super-utilizers, the characteristics of which we identified through a multivariate generalized logistic model.

Results: Of 1299 eligible patients, mean age was 60 years, 73% were female and 92% were Caucasian. Super-utilizers were older (+2.1 years; p = 0.012), had greater depression (34.2 vs 25.7%; p = 0.03), increased frailty (p = 0.009) comorbidities (p = 0.005), higher reoperation rates (54.4 vs 15.0%; p < 0.001), hospital length of stay (+ 3 days; p < 0.0001), higher surgical invasiveness (+28.6; p < 0.001), more vertebrae fused (+ 3; p < 0.0001); interbody fusions (80 vs 55%; p < 0.0001), bone morphogenetic protein (BMP) use (87.3 vs 69.4%; p = 0.0001), operative time (+91 min; p < 0.0001), and blood loss (+620 mL; p < 0.0001) compared to other ASD patients. Index cost was 65% (p < 0.0001), and cost/quality-adjusted life-year was three times higher among super-utilizers.

Conclusion: ASD patients with depression who undergo more complex or revision spinal surgical procedures are more likely to be super-utilizers. Identifying likely super-utilizers within the ASD population may enable targeted interventions and preoperative planning to reduce unnecessary costs, while improving patient outcomes.