title: Application of holmium yttrium aluminium garnet (YAG) laser in treatment of acquired posterior choanal atresia following radiotherapy for nasopharyngeal carcinoma.
abstract: OBJECTIVE
  To report on the use of holmium yttrium aluminium garnet (YAG) laser in the treatment of acquired posterior choanal atresia following radiotherapy in patients with nasopharyngeal carcinoma.
  
  
  METHODS
  Five patients with acquired bilateral choanal atresia and two with unilateral choanal atresia in the posterior choanae were identified following treatment of nasopharyngeal carcinoma by external radiotherapy, from July 1998 to April 1999. The mean age was 44.6 years (range, 22-65 years). Two patients had stage two and five had stage three disease according to Ho's classification. All patients received 66 Gy of external irradiation delivered to the nasopharynx and a mean dose of 61 Gy (39.8-72 Gy) to the neck. Five patients received an additional external boost of 20 Gy and two received 14 Gy delivered to the parapharyngeal region. Two other patients also received intracavitatory brachytherapy of 18 Gy delivered to the nasopharynx. One patient had concurrent chemotherapy by cisplatinum during external radiotherapy. The mean onset of nasal symptoms was 17 months (range, 2-38 months) following irradiation. All patients were treated by transnasal endoscopic holmium YAG laser resection. Merocel epistaxis packing and a modified nasopharyngeal tube were used to stent the nasal airway for two weeks post-operatively.
  
  
  RESULTS
  The mean follow up was 26.8 months (range, 20-32 months) after surgery. All patients were symptom free on follow up. Five patients (71 per cent) retained full patency in the posterior choanae. Two patients (28 per cent) had bilateral mild restenosis in the postnasal space, not requiring revision surgery. The surgical fields were almost bloodless. No adverse post-operative complications occurred, except for delayed nasal septal perforation in one patient and unilateral exposure of the septal cartilage in another; no further treatment was required in either patient.
  
  
  CONCLUSIONS
  Acquired posterior choanal atresia is an unusual complication following radiotherapy, and it can occur early after treatment. It can be successfully treated by transnasal endoscopic holmium YAG laser resection of the scar tissue, with minimal bleeding. A two week period of Merocel nasal packing and nasopharyngeal tube stenting was sufficient to prevent severe restenosis in the posterior choanae; nasal breathing through the tube lumen was possible during this time.
authors.affiliation: Division of Otorhinolaryngology, Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China.
authors.forename: Peter K M
authors.initials: PK
authors.lastname: Ku
authors.forename: Michael C F
authors.initials: MC
authors.lastname: Tong
authors.forename: Andrew
authors.initials: A
authors.lastname: van Hasselt
mesh_terms: D000328:Adult; D000368:Aged; D002754:Choanal Atresia / Q000209:etiology / Q000601:surgery*; D005260:Female; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage; D016896:Treatment Outcome