title: Reliability of distraction vector transfer in unilateral vertical distraction of the mandibular ramus.
abstract: Mandibular distraction osteogenesis fails in correcting the skeletal deformities if the vector of distraction is incorrect. Lack of vector control is caused mainly by two factors: first, deficient vector planning and transfer, and, second, resistance of the masticatory muscles and the remaining soft tissue envelope toward elongation. To enhance predictable placement of intraoral distraction devices during surgery and thereby the treatment outcome, a method combining planning, simulation, and transfer was developed. The presurgical planning was based on frontal and lateral head films, and the planned position and orientation of the distraction device was applied on the stereolithographic model. This model was cut according to the planned osteotomy, and the distraction was simulated. The transfer procedure copied the planned and simulated position of the distraction device during surgery by use of an individual guiding splint. The guiding splint was fabricated on plaster models, and transferred to the stereolithographic model to reproduce the planned and simulated distraction treatment during surgery. The reliability of the vector-transfer method was evaluated cephalometrically in a homogenous group of 13 patients and their respective stereolithographic models in comparison with the planned, simulated, and transferred distraction vectors.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Noerrebrogade 44, Bygning 9D, DK-8000 Aarhus C, Denmark. tkofo@akh.aaa.dk
authors.forename: Thomas
authors.initials: T
authors.lastname: Kofod
authors.forename: Sven Erik
authors.initials: SE
authors.lastname: Nørholt
authors.forename: Thomas Klit
authors.initials: TK
authors.lastname: Pedersen
authors.forename: John
authors.initials: J
authors.lastname: Jensen
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D002648:Child; D017076:Computer-Aided Design; D005146:Facial Asymmetry / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery*; D008410:Masticatory Muscles / Q000503:physiopathology; D008953:Models, Anatomic; D024343:Open Bite / Q000601:surgery; D019857:Osteogenesis, Distraction / Q000295:instrumentation / Q000379:methods*; D010347:Patient Care Planning; D013165:Splints; D036542:Tomography, Spiral Computed