title: [Mandibular osteoradionecrosis (ORN) as a side effect of head and neck cancer treatment: Factors that induce it].
abstract: BACKGROUND
  Osteoradionecrosis of the mandible is a relatively common complication in patients with head and neck cancer undergoing radiotherapy or concomitant chemoradiotherapy, characterized by exposure of the mandibular bone either in the mouth or in the facial skin, with no improvement with conservative treatment for six months. The risk factors are radiotherapy in head and neck region, lack of dental prophylaxis before treatment and dental extraction.
  
  
  METHODS
  Retrospective observational study analyzing incidence and etiologic factors of osteoradionecrosis in 250 patients undergoing radiotherapy or combined treatment of cervicofacial area between 2002 and 2010.
  
  
  RESULTS
  25 patients were included; the horizontal branch was the most affected area, followed by the anterior arch. Associated factors were: stage (T4a and T4b), tumor location (oral cavity), dental extraction pre or post-radiotherapy, and radiotherapy time (pre-or postoperative); 72% had association with tooth extraction. Only five patients had control with conservative measures, and 20 required some type of mandibulectomy, only three of them were candidates for reconstruction with fibular free flap; none received treatment in a hyperbaric chamber.
  
  
  CONCLUSIONS
  The data suggest that osteoradionecrosis has a multifactorial origin, and prevention is the best alternative and includes pretreatment dental prophylaxis to avoid tooth extractions and close monitoring and surveillance in order to identify early osteoradionecrosis. Most patients require mandible resection as definitive treatment.
authors.affiliation: Departamento de Tumores de Cabeza y Cuello, Hospital de Oncología, Centro Médico Nacional Siglo XXI (CMN SXXI), IMSS, Ciudad de México, México.
authors.forename: José Francisco
authors.initials: JF
authors.lastname: Gallegos-Hernández
authors.affiliation: Departamento de Tumores de Cabeza y Cuello, Hospital de Oncología, Centro Médico Nacional Siglo XXI (CMN SXXI), IMSS, Ciudad de México, México.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Reyes-Vivanco
authors.affiliation: Departamento de Tumores de Cabeza y Cuello, Hospital de Oncología, Centro Médico Nacional Siglo XXI (CMN SXXI), IMSS, Ciudad de México, México.
authors.forename: Héctor
authors.initials: H
authors.lastname: Arias-Ceballos
authors.affiliation: Departamento de Tumores de Cabeza y Cuello, Hospital de Oncología, Centro Médico Nacional Siglo XXI (CMN SXXI), IMSS, Ciudad de México, México.
authors.forename: Gerardo Gabriel
authors.initials: GG
authors.lastname: Minauro-Muñoz
authors.affiliation: Departamento de Tumores de Cabeza y Cuello, Hospital de Oncología, Centro Médico Nacional Siglo XXI (CMN SXXI), IMSS, Ciudad de México, México.
authors.forename: Alma Lilia
authors.initials: AL
authors.lastname: Ortiz-Maldonado
authors.affiliation: Departamento de Tumores de Cabeza y Cuello, Hospital de Oncología, Centro Médico Nacional Siglo XXI (CMN SXXI), IMSS, Ciudad de México, México.
authors.forename: Daniel Israel
authors.initials: DI
authors.lastname: García-Ruiz
authors.affiliation: Departamento de Tumores de Cabeza y Cuello, Hospital de Oncología, Centro Médico Nacional Siglo XXI (CMN SXXI), IMSS, Ciudad de México, México.
authors.forename: Martín
authors.initials: M
authors.lastname: Hernández-Sanjuán
mesh_terms: D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008334:Mandible / Q000528:radiation effects; D008336:Mandibular Diseases / Q000209:etiology*; D008875:Middle Aged; D010025:Osteoradionecrosis / Q000209:etiology* / Q000517:prevention & control; D012189:Retrospective Studies; D014081:Tooth Extraction / Q000009:adverse effects*