Abstract: A Prospective Study of Forces in Craniofacial Distraction (Plastic Surgery The Meeting (September 28

Saturday, September 29, 2018: 5:25 PM

Ari M Wes, BA , The Children's Hospital of Philadelphia, Philadelphia, PA

Lawrence O Lin, BS , Division of Plastic and Reconstructive Surgery, Children's Hospital of Philadelphia, Philadelphia, PA

Daniel M Mazzaferro, MD, MBA , Division of Plastic and Reconstructive Surgery, Children's Hospital of Philadelphia, Philadelphia, PA

Rosaline S Zhang, BA , Division of Plastic and Reconstructive Surgery, Children's Hospital of Philadelphia, Philadelphia, PA

Ian C. Hoppe, MD , Division of Plastic and Reconstructive Surgery, Department of Surgery, Rutgers - New Jersey Medical School, Newark, NJ

Scott P Bartlett, MD , Division of Plastic and Reconstructive Surgery, Children's Hospital of Philadelphia, Philadelphia, PA

Jesse A Taylor, MD , Division of Plastic and Reconstructive Surgery, Children's Hospital of Philadelphia, Philadelphia, PA

Background: While much has been written about the variables “distance” and “rhythm” in craniofacial distraction osteogenesis (CMF DO), little is known about the forces involved. The purpose of this study is to study force magnitudes and force trends in CMF DO and associate these forces to operative outcomes.

Methods: Seventeen patients undergoing distraction of the mandible or cranial vault with a semi-buried KLS-Martin (KLS-Martin, Tuttlingen, Germany) distractor, were included in this prospective study. Subjects’ distractors were activated each day by study personnel, using a digital torque-measuring screwdriver. Torque measurements were then converted into generalizable force values and associated with patient outcomes.

Results: Cranial vault distraction (CVDO) was performed on 7 subjects (41.2%), and mandibular distraction (MDO) on 10 subjects (58.8%). Across the entire cohort, the maximum force per activation was 27.023.5 N, and the elastic force (the rise in force over a single activation) was 10.714.1 N. Maximum force (CVDO:52.920.2 N vs. MDO: 12.98.5 N; p<0.0001), and elastic force (CVDO: 22.015.6 N vs. MDO: 4.58.2 N; p<0.0001) were significantly higher in the CVDO sub-group than in the MDO cohort. On multivariate regression analysis, statistically significant associations were seen between maximum activation force and the following independent variables: active DO day number (beta-coefficient: 1.1; P<0.001), DO rate (mm/day) (beta-coefficient: 8.9; P=0.016), CVDO (relative to MDO) (beta-coefficient: 41.4; P<0.001), and device failure (beta-coefficient: 10.3; P=0.004).

Conclusion: In CMF DO, both the magnitude of, and the trend in forces are relatively predictable, and correlate significantly with easily discernable factors such as DO-modality (MDO vs. CVDO), DO rate, and other factors. Deviations from these predictable force magnitudes and trends are correlated with systems failures. A more thorough understanding of the normal and abnormal states, as they relate to force measurements, may allow for novel diagnostic and prognostic tools, and a better heuristic with which clinicians can optimize DO protocols for the patients.

35088 A Prospective Study of Forces in Craniofacial Distraction