title: Fourth branchial pouch sinus: from diagnosis to treatment.
abstract: BACKGROUND
  Fourth branchial pouch sinus (FBPS) is rare and frequently unknown to clinicians. Misdiagnosis is common and definitive surgery is often made difficult by previous episodes of infection and failed attempts at excision. The purpose of this paper is to clarify the diagnostic criteria and the methods used for the surgical management of FBPS.
  
  
  METHODS
  From a series of 265 head and neck cysts and fistulae, 7 cases of FBPS were retrospectively reviewed. The surgical technique is detailed.
  
  
  RESULTS
  Six cases were located on the left side and one on the right. CT scanning showed an air-filled structure on both sides of the lesser horn of the thyroid cartilage in 2 cases out of 4, and barium swallow found a FBPS in 1 case out of 3. Direct pharyngoscopy allowed confirmation of the diagnosis in all cases and permitted catheterization of the tract with the spring guidewire of a vascular catheter which helped surgical location and subsequent dissection. The recurrent laryngeal nerve was systematically dissected to avoid inadvertent damage. A hemi-thyroidectomy was performed in one case. A transient laryngeal paralysis (lasting 9 months) was noted in a 3-week-old newborn operated on. None of the 7 cases had a recurrence after complete resection of the FBPS (3.7 years average follow-up).
  
  
  CONCLUSIONS
  Symptoms on the right side do not exclude the diagnosis of a FBPS. Endoscopy is the key investigation. It allows confirmation of the diagnosis and catheterization of the tract, which aids the surgical dissection. Total removal of the sinus tract tissue with dissection and preservation of the recurrent laryngeal nerve is recommended.
  
  
  METHODS
  A-1.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery "A", CHU Gui de Chauliac, 34295 Montpellier, France. r-garrel@chu-montpellier.fr
authors.forename: Renaud
authors.initials: R
authors.lastname: Garrel
authors.forename: Elham
authors.initials: E
authors.lastname: Jouzdani
authors.forename: Quentin
authors.initials: Q
authors.lastname: Gardiner
authors.forename: Marc
authors.initials: M
authors.lastname: Makeieff
authors.forename: Michel
authors.initials: M
authors.lastname: Mondain
authors.forename: Paul
authors.initials: P
authors.lastname: Hagen
authors.forename: Louis
authors.initials: L
authors.lastname: Crampette
authors.forename: Bernard
authors.initials: B
authors.lastname: Guerrier
mesh_terms: D000293:Adolescent; D000328:Adult; D001935:Branchioma / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D002675:Child, Preschool; D004724:Endoscopy; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D006801:Humans; D008297:Male; D037981:Neck Dissection; D012189:Retrospective Studies; D016896:Treatment Outcome