Range of curvilinear distraction devices required for treatment of mandibular deformities.
OBJECTIVE
The purpose of this study was to determine the range of fixed trajectory curvilinear distraction devices required to correct a variety of severe mandibular deformities.


METHODS
Preoperative computed tomography (CT) scans from 18 patients with mandibular deformities were imported into a CT-based software program (Osteoplan). Three-dimensional virtual models of the individual skulls were made with landmarks to track movements. An ideal treatment plan was created for each patient. Upper and lower boundaries for the dimensions of curvilinear distractors were established based on manufacturing and geometric constraints. Then, anatomically acceptable distractor attachment points were identified on the models using proximal and distal grids. Treatment plans were simulated for a series of distractors with varying radii of curvature, elongations (arc-length of device), and placements along the grids. The outcomes using these distractors were compared with the ideal treatment plans. Discrepancies were quantified in millimeters by comparing landmarks in the simulated versus ideal movements.


RESULTS
Approximately 400,000 simulated 3-dimensional movements, based on the distractor parameters and variations in placement were computationally evaluated for the 18 cases. It was determined that, by varying distractor placement, a family of 5 distractors, with 3, 5, 7, and 10 cm radii of curvature and a straight-line device, could be used to treat all 18 cases to within 1.8 mm of error.


CONCLUSIONS
The results of this study indicate that a family of 5 curvilinear distractors may suffice to treat a broad range of mandibular deformities.
Ritter
Lutz
L
Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston, MA, USA.
Yeshwant
Krishna
K
Seldin
Edward B
EB
Kaban
Leonard B
LB
Gateno
Jaime
J
Keeve
Erwin
E
Kikinis
Ron
R
Troulis
Maria J
MJ
D003198:Computer Simulation; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008334:Mandible / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000601:surgery; D008338:Mandibular Injuries / Q000000981:diagnostic imaging / Q000601:surgery; D019857:Osteogenesis, Distraction / Q000295:instrumentation* / Q000379:methods; D010347:Patient Care Planning; D013813:Therapy, Computer-Assisted; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome