Although recent single-institution series have reported low morbidity and zero mortality after substernal thyroidectomy, a direct comparison of outcomes between substernal thyroidectomy and conventional cervical thyroidectomy has not been performed. We hypothesized that substernal thyroidectomy would be associated with higher morbidity and mortality as compared with cervical thyroidectomy.

Data were extracted from the New York State Statewide Planning and Research Cooperative System database for the years 1998 to 2004. The primary predictor variable was substernal as compared with cervical thyroidectomy. Outcomes variables included postoperative complications, length of stay, and mortality. Multiple logistic regression was used to access the independent effects of substernal thyroidectomy on postoperative outcome.

A total of 33,930 patients underwent thyroidectomy, 1,153 (3.4%) of whom underwent substernal thyroidectomy. Compared with patients who underwent cervical thyroidectomy (n = 32,777), patients who underwent substernal thyroidectomy were older (p < 0.0001), more likely to have a comorbid condition (p < 0.0001), more likely to be men (p < 0.0001), more likely to lack private insurance (p < 0.0001), more likely to undergo total thyroidectomy (p < 0.0001), less likely to undergo thyroidectomy for malignancy (p < 0.0001), and less likely to undergo thyroidectomy at a high-volume center (p = 0.001). After controlling for these covariates, patients who underwent substernal thyroidectomy were considerably more likely to experience recurrent laryngeal nerve injury (p = 0.0002), postoperative bleeding (p = 0.004), deep venous thrombosis (p = 0.0002), and respiratory failure (p < 0.0001), and were more likely to receive a red blood cell transfusion (p < 0.0001). Patients who underwent substernal thyroidectomy also had a considerably increased length of stay (p < 0.0001), and more than an eightfold increase in likelihood of mortality (p < 0.0001).

Substernal thyroidectomy, as compared with cervical thyroidectomy, is associated with a markedly increased likelihood of both postoperative complications and mortality.