Volume-Outcome Relationship in Surgical Interventions for Spinal Metastases.

BACKGROUND: Surgery for spinal metastases is challenging and carries a high risk of perioperative morbidity and mortality. Procedures with such characteristics often exhibit a volume-outcome relationship. This has not been previously characterized for spinal metastasis surgery to our knowledge.

METHODS: The Florida State Inpatient Database (2011 through 2014) was queried to identify patients who had undergone surgery for spinal metastases. Surgeon and hospital surgical volumes were compared with 90-day complication and readmission rates to develop procedural cut-points used to define high and low-volume providers. These were included in a multivariable logistic regression analysis that was adjusted for confounders. A separate analysis was performed to evaluate the effect of race/ethnicity and insurance status on the likelihood of receiving care from a high-volume surgeon or hospital.

RESULTS: This study included 3,135 patients treated by 1,488 surgeons at 162 hospitals. Patients treated at low-volume hospitals had significantly higher odds of having postoperative complications (odds ratio [OR] = 1.47; 95% confidence interval [CI] = 1.13, 1.91) and readmissions (OR = 1.36; 95% CI = 1.06, 1.75). Those treated by low-volume surgeons also demonstrated a higher likelihood of complications (OR = 1.40; 95% CI = 1.16, 1.69) and readmissions (OR = 1.38; 95% CI = 1.17, 1.62). The likelihood of receiving intervention from a high-volume surgeon was significantly lower for African Americans (OR = 0.55; 95% CI = 0.41, 0.75) and Hispanics (OR = 0.60; 95% CI = 0.44, 0.83). The odds of being treated at a high-volume hospital were also significantly lower for African Americans (OR = 0.58; 95% CI = 0.40, 0.84) and Hispanics (OR = 0.28; 95% CI = 0.20, 0.38).

CONCLUSIONS: There is a clear relationship between the volume and outcomes of surgical treatment of spinal metastases, with high-volume providers demonstrating reduced complication and readmission rates. Racial and ethnic minorities appear to experience health-care segregation when it comes to surgical care for spinal metastases. Regionalization of care for these conditions may help improve access to high-volume providers and mitigate disparities in care.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.