Fourth branchial arch sinus: Clinical presentation, diagnostic workup, and surgical treatment

Objectives/Hypothesis: Abnormalities of the fourth branchial arch are much less common than those of the second arch and present in a different manner. The authors report their experience with five cases of fourth arch sinuses. Methods: Retrospective chart review of patients at a tertiary care center. Results: All patients presented in the first or second decade of life, and all but one had left-sided neck involvement. Four patients presented with recurrent low neck inflammatory episodes, and one with respiratory compromise. Diagnostic studies performed included ultrasound, computed tomography (CT) scan, barium swallow, magnetic resonance imaging, and fine-needle aspiration. Barium contrast studies and CT scan were the most useful in demonstrating a fourth arch sinus tract preoperatively. Surgical treatment with an emphasis on complete exposure of the recurrent laryngeal nerve and exposure of the lateral piriform sinus to facilitate complete sinus tract excision was successful in all patients. Conclusion: The clinical history of recurrent low neck inflammatory episodes in young patients, especially on the left side, should raise the suspicion of this entity. Investigation using barium swallow in combination with CT scanning is useful. Excision of the sinus tract taking care not to injure the recurrent laryngeal nerve is curative.