Effect of hospital volume of thyroidectomies on outcomes following substernal thyroidectomy

Background Substernal thyroidectomy (ST), as compared to conventional, cervical thyroidectomy, is a technically demanding procedure that is associated with increased morbidity and mortality. We tested the hypothesis that outcomes following ST are improved at centers that perform a high volume of thyroidectomies. Methods Patients who underwent ST from 1998 to 2004 were extracted from the New York State Statewide Planning and Research Cooperative System database. Hospital volume of thyroidectomies was divided into low (< 33 per year), middle (33-99 per year), and high (>= 100 per year) volumes. Outcome variables included hospital length of stay (LOS), recurrent laryngeal nerve (RLN) injury, hypoparathyroidism, postoperative bleeding, respiratory failure, blood transfusion, and mortality. Results A total of 1153 STs were analyzed; 372 (32.2%) were performed at low-volume centers, 388 (33.7%) at middle-volume centers, and 393 (34.0%) at high-volume centers. Linear associations were observed between increasing hospital volume of thyroidectomies and decreasing age (p = 0.003), increasing co-morbidity (p < 0.0001), increased likelihood of total versus subtotal thyroidectomy (p < 0.0001), and increased likelihood of thyroid malignancy (p < 0.0001). Despite this, increasing hospital volume of thyroidectomies predicted a decreased likelihood of overall complications (p = 0.005), postoperative bleeding (p = 0.01), blood transfusion (p = 0.04), respiratory failure (p = 0.04) and mortality (p = 0.004), as well as a trend toward a decreased LOS (p = 0.06). The overall complication rate and the mortality rate remained significantly associated with volume group by multivariate analysis. Conclusion Despite more extensive surgery on patients with greater co-morbidity, LOS, morbidity, and mortality were all decreased when ST occurred at hospitals that perform a high volume of thyroidectomies.