title: Analysis of microvascular free flaps for reconstruction of advanced mandibular osteoradionecrosis: a retrospective cohort study.
abstract: OBJECTIVE
  Previous studies have suggested that radiation therapy does not impact local complication rates after microvascular free flap (MVFF) reconstruction for head and neck cancer. There is little data, however, indicating whether or not the presence of osteoradionecrosis (ORN) affects treatment outcome. The purpose of this retrospective cohort study is to review the outcome of patients undergoing MVFF reconstruction for ORN and to determine if there is a difference in outcome and/or complications when compared to similarly reconstructed patients who received radiation therapy but did not develop ORN, as well as un-radiated controls.
  
  
  METHODS
  The records of 305 consecutive patients who underwent MVFF reconstruction for a variety of cancer-related therapies or post-traumatic craniofacial defects from 1994 to 2004 were reviewed. Of these, all patients who underwent surgery for Marx stage III ORN involving the mandible were identified (n = 21). For purposes of comparison, patients who received preoperative radiation therapy (XRT) and underwent similar reconstruction but did not have ORN were identified and included in the study group. Similarly matched patients who never received XRT served as controls. Patients were reconstructed with a variety of MVFFs harvested from the fibula (n = 48), radial forearm (n = 11), rectus abdominus (n = 3), latissimus dorsi (n = 3), serratus anterior (n = 1) and iliac crest (n = 1). The study cohort was divided according to XRT status: group 1 (ORN), patients that received XRT and developed ORN (n = 21); group 2 (no ORN), patients that received XRT but did not develop ORN (n = 21); and group 3 (control), patients that never received XRT (n = 25). The following data were collected: age, gender, diagnosis, recipient site, donor site, hyperbaric oxygen therapy (HBO), flap complications, flap survival, patient survival. Outcome measures were defined as flap survival, complications and resolution of ORN. Descriptive statistics were recorded and an analysis of variance was calculated to evaluate differences between the 3 groups. The Fisher's exact test was used to evaluate whether a complication occurred more frequently in any one particular group.
  
  
  RESULTS
  The mean age of the 67 patients included in the study was 57 years (SD = 15.4) years (M = 32, F = 35) and there were no significant demographic differences between the 3 groups (P = .8528). All patients were successfully reconstructed although 21% required reoperation for various reasons. Overall flap survival was 88% (ORN = 86%, no ORN = 87%, control = 90%) and there was no difference between the 3 groups studied (P = 1.0). Complications were evenly distributed among the 3 groups (50% overall) and included skin necrosis (P = .824), wound infection (P = .6374), salivary fistula (P = .1178), and partial flap loss (P = 1.0). Carotid blowout occurred in 2 patients in the ORN group, however, this was not statistically significant (P = .1844). Fourteen of the 21 patients in the ORN group had received preoperative HBO.
  
  
  CONCLUSIONS
  Overall MVFF survival and complication rates among patients with ORN versus control groups are the same in this study cohort. Free tissue transfer is a viable option for advanced mandibular ORN.
authors.affiliation: Head and Neck Surgery, Legacy Emanuel Hospital and Health Center, Portland, OR, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Hirsch
authors.forename: R Bryan
authors.initials: RB
authors.lastname: Bell
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Dierks
authors.forename: Jason K
authors.initials: JK
authors.lastname: Potter
authors.forename: Bryce E
authors.initials: BE
authors.lastname: Potter
mesh_terms: D016025:Bone Transplantation; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy; D002342:Carotid Artery, External; D016022:Case-Control Studies; D015331:Cohort Studies; D016371:Cranial Irradiation / Q000009:adverse effects; D005260:Female; D005360:Fibula / Q000601:surgery; D006085:Graft Survival; D006258:Head and Neck Neoplasms / Q000532:radiotherapy; D006801:Humans; D006931:Hyperbaric Oxygenation; D007601:Jugular Veins; D008297:Male; D008334:Mandible / Q000601:surgery; D008336:Mandibular Diseases / Q000601:surgery*; D055806:Microvessels; D008875:Middle Aged; D019647:Oral Surgical Procedures / Q000379:methods*; D010025:Osteoradionecrosis / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods*; D012189:Retrospective Studies; D016038:Skin Transplantation; D013524:Surgical Flaps / Q000098:blood supply; D016896:Treatment Outcome