Hypothyroidism Predicts Fistula Development Following Salvage Oropharyngectomy.

Importance: Previous work demonstrated postoperative hypothyroidism adversely affects wound healing in salvage laryngectomy. Currently, no studies have evaluated the association between wound healing and hypothyroidism in patients undergoing salvage oropharyngectomy.

Objective: The primary objective was studying hypothyroidism and other factors associated with oropharyngocutaneous fistula development and fistula requiring reoperation within 30 days after salvage oropharyngectomy.

Design: Retrospective cohort study.

Setting: Tertiary academic center.

Participants: All patients who underwent salvage oropharyngectomy for recurrent or second primary oropharyngeal squamous cell carcinoma between 2001 and 2017 after radiation or chemoradiation. Patients with no preoperative thyroid-stimulating hormone (TSH) values were excluded.

Exposures: Salvage oropharyngectomy for recurrent or second primary oropharyngeal squamous cell carcinoma.

Main outcomes measures: The principle explanatory variable was postoperative hypothyroidism, defined as TSH greater than 5.5 mIU/L. Univariate, bivariate, and binary logistical regression multivariate analysis was performed.

Results: Fifty-three patients met inclusion criteria, 37.7% of patients developed hypothyroidism, 18.9% developed a fistula, and 9.4% required an operation to manage the fistula. Postoperative fistula rate was 35% among hypothyroid patients, which was significantly greater than among euthyroid patients (9.1%; P = .03). A fistula requiring reoperation occurred in 20% of hypothyroid patients compared with that of euthyroid patients (3%; P = .061). In a multivariate analysis, postoperative hypothyroid patients were at a 9.5-fold increased risk of developing a fistula [95% confidence interval (CI) 1.6-57.0, P = .013]. Additionally, postoperative hypothyroid patients were at 13.6-fold increased risk for development of a fistula requiring reoperation (95% CI 1.2-160.5, P = .038).

Conclusions and relevance: Postoperative hypothyroidism in patients who underwent salvage oropharyngectomy can predict fistula development and fistula requiring operative management. This study supports the treatment of hypothyroidism after surgery to reduce wound complications.