The Contribution of Hospital Volume, Payer Status, and Other Factors on the Surgical Outcomes of Scoliosis Patients: A Review of 3,606 Cases in the State of California

While volume/outcomes relationships have been shown for several areas of orthopaedics, previous studies have not examined this relationship in the area of scoliosis surgery. The Office of Statewide Planning and Development (OSHPD) California inpatient discharge database was used for a retrospective review of all patients 25 years of age or younger with a diagnosis of scoliosis and a spinal fusion procedure from 1995 to 1999 (n = 3,606). Univariate and multivariate analyses were conducted to determine the effect of various factors on in-hospital mortality, surgical complications, reoperations, and length of stay (LOS). Univariate analyses revealed significant effects of age, sex, illness severity, neuromuscular disease, surgical approach, Medicaid status, and annual hospital volume on outcomes (P < 0.05). After controlling for these factors using multivariate regression, patients insured by Medicaid were found to have a significantly greater odds for complications (P = 0.017) and a significantly increased LOS (P < 0.001) compared with patients with all other sources of payment. Additionally, multivariate regression revealed an inverse relationship between annual hospital volume and likelihood of reoperation, as patients treated at hospitals with annual volumes of 5.1 to 25.0, 25.1 to 50.0, and greater than 50.0 spinal fusions all had approximately half the odds of reoperation (P = 0.042, P = 0.004, and P = 0.028 respectively) as patients treated at hospitals with an annual volume of 5.0 or fewer spinal fusions per year. The current data suggest that being insured with Medicaid in the state of California is associated with poorer outcomes after scoliosis surgery. Additionally, this study documents a volume/outcomes relationship in scoliosis surgery.