title: Osteoradionecrosis of the mandible: a case series at a single institution.
abstract: BACKGROUND
  Osteoradionecrosis (ORN) defines exposed irradiated bone, which fails to heal over a period of 3-6 months without evidence of residual or recurrent tumor. In the previous decades, a staging and treatment protocol suggested by Marx, has dominated the approach to ORN. However, recently this paradigm is shifting. The purpose of this study was to evaluate our institutional experience in managing ORN through a retrospective review of case series from a large urban academic cancer centre.
  
  
  METHODS
  A retrospective chart review was conducted to include all ORN cases from 2003 to 2009 diagnosed at the Department of Otolaryngology - Head and Neck Surgery and the Department of Dentistry. The staging of ORN was assessed as affected by tumor site, tumor stage, radiotherapy modality and dose, chemotherapy, dental work, and time to diagnosis. The effectiveness of hyperbaric oxygen therapy (HBO) and surgery in the management of ORN was evaluated.
  
  
  RESULTS
  Fourteen cases of ORN were documented (incidence 0.84%). Primary subsites included tonsils, tongue, retromolar trigone, parotid gland, soft palate and buccal mucosa. There were 5 (35.7%) stage 1, 3 (21.4%) stage 2, and 6 (42.9%) stage 3 cases. ORN severity was not significantly associated with gender, smoking, alcohol use, tumor site, T stage, N stage, AJCC stage, or treatment modality (radiation alone, surgery with adjuvant radiation or adjuvant chemoradiation). Patients treated with intensity-modulated radiotherapy developed less severe ORN compared to those treated with conventional radiotherapy (p < 0.015). ORN stage did not correlate with radiation dose. In one patient only dental procedures were performed following radiation and could be implicated as the cause of ORN. HBO therapy failed to prevent ORN progression. Surgical treatment was required for most stage 2 (partial resections and free tissue transfers) and stage 3 patients (mandibulectomies and free tissue transfers, including two flaps in one patient). At an average follow up of 26 months, all patients were cancer-free, and there was no evidence of ORN in 84% of patients.
  
  
  CONCLUSIONS
  In early ORN, we advocate a conservative approach with local care, while reserving radical resections with robust reconstruction with vascularized free tissue for advanced stages.
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Room M1-102, Toronto, ON, M4N 3M5, Canada. kevin.higgins@sunnybrook.ca.
authors.forename: Artur
authors.initials: A
authors.lastname: Gevorgyan
authors.forename: Kevin
authors.initials: K
authors.lastname: Wong
authors.forename: Ian
authors.initials: I
authors.lastname: Poon
authors.forename: Nick
authors.initials: N
authors.lastname: Blanas
authors.forename: Danny J
authors.initials: DJ
authors.lastname: Enepekides
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Higgins
mesh_terms: D003131:Combined Modality Therapy; D003646:Debridement; D018450:Disease Progression; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation; D008297:Male; D008334:Mandible / Q000601:surgery; D008336:Mandibular Diseases / Q000473:pathology*; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000188:drug therapy / Q000532:radiotherapy / Q000601:surgery*; D010025:Osteoradionecrosis / Q000453:epidemiology*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated; D019651:Plastic Surgery Procedures / Q000379:methods; D012189:Retrospective Studies; D012307:Risk Factors; D013524:Surgical Flaps
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