title: Continuous mandibular distraction osteogenesis: novel device and preliminary results in minipigs.
abstract: OBJECTIVE
  To develop and test a novel, hydraulic, continuous, automated distraction device capable of 3D movements for treatment of mandibular deformities.
  
  
  METHODS
  We used 2 cadaveric and 5 live female Yucatan minipigs to test the distractor. The 3 components (miniature buried distractor, external power and control box, and user interface on handheld computer) operate on a closed loop in which the hydraulic pulse strength correlates with the resistance of the bone and soft tissue. The system auto-adjusts to correct any discrepancy between the actual and desired position of mandibular fragments. The distraction protocol included 0-day latency, 1 mm (divided into 94 increments) per day, and 24 days' fixation. Clinical examination was performed and lateral and anteroposterior cephalometric radiographs were obtained preoperatively and postoperatively, at mid distraction osteogenesis (DO), end DO, and end fixation. Position information was obtained through the user interface.
  
  
  RESULTS
  Both cadaveric trials resulted in the desired distraction gap (11 to 12 mm), with all components functioning as designed. In 4 of the 5 live animals, distraction averaged 7.29 mm (range, 5 to 11 mm) over 12 days of activation. In 3 of the 5 live animals, the osteotomy gap filled in with bone by 24 days of fixation. Two animals were sacrificed prematurely (1 at mid DO and 1 at end DO) because vital components malfunctioned.
  
  
  CONCLUSIONS
  The device is capable of automated, continuous, hydraulically powered DO at a rate of 1 mm/d. Future work will be directed at fortifying the device components and testing it in larger numbers of animals at varying distraction rates.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: Batya R
authors.initials: BR
authors.lastname: Goldwaser
authors.forename: John
authors.initials: J
authors.lastname: Magill
authors.forename: Maria E
authors.initials: ME
authors.lastname: Papadaki
authors.forename: Martyn
authors.initials: M
authors.lastname: Byl
authors.forename: Roger
authors.initials: R
authors.lastname: Kromann
authors.forename: Brent
authors.initials: B
authors.lastname: Yates
authors.forename: Joe
authors.initials: J
authors.lastname: Morency
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Kaban
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Troulis
mesh_terms: D000818:Animals; D034201:Computers, Handheld; D005260:Female; D008334:Mandible / Q000601:surgery*; D019857:Osteogenesis, Distraction / Q000295:instrumentation*; D010027:Osteotomy / Q000295:instrumentation; D013552:Swine; D013556:Swine, Miniature; D014584:User-Computer Interface; D014867:Water
chemical_list: D014867:Water