title: Distraction osteogenesis following low-dose hyperfractionated irradiation in the rat mandible.
abstract: OBJECTIVE
  The investigators hypothesized that low-dose hyperfractionated radiation would impair mandibular distraction osteogenesis (DO) in a murine mandibular model.
  
  
  METHODS
  Male Sprague-Dawley rats underwent fractionated radiation (30 Gy) of the left mandible. After a 2-week recovery period, an external frame distractor was applied and gradual distraction of the mandible was performed. Tissue was harvested after a 28-day consolidation period. Gross, radiologic, and histologic evaluations were undertaken. Control animals underwent surgery for an identical time frame without preoperative radiation.
  
  
  RESULTS
  Animals subjected to preoperative radiation (n = 10) showed suboptimal bone formation, including bone atrophy, incomplete bridging of the distraction gap, and gross bony defects or nonunion, compared with controls (n = 10). Although physical lengthening was achieved, irradiation consistently led to a detrimental effect on the normal process of DO.
  
  
  CONCLUSIONS
  This set of experiments establishes a valuable rodent model to evaluate the effects of radiation on DO and may help to formulate strategies to optimize DO before it is widely applied in oncologic reconstruction.
authors.affiliation: Craniofacial Research Laboratory, Section of Plastic Surgery, University of Michigan, Ann Arbor, MI 48104, USA. sdeshpa@umich.edu
authors.forename: Sagar S
authors.initials: SS
authors.lastname: Deshpande
authors.forename: Laura A
authors.initials: LA
authors.lastname: Monson
authors.forename: Christi M
authors.initials: CM
authors.lastname: Cavaliere
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Ayzengart
authors.forename: Steven R
authors.initials: SR
authors.lastname: Buchman
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000528:radiation effects*; D016371:Cranial Irradiation; D019583:Dose Fractionation, Radiation; D008297:Male; D008334:Mandible / Q000528:radiation effects* / Q000601:surgery*; D019857:Osteogenesis, Distraction; D051381:Rats; D017207:Rats, Sprague-Dawley