Pierre Robin sequence and Treacher Collins syndrome are both associated with mandibular hypoplasia. It has been hypothesized, however, that the mandible may be differentially affected. The purpose of this study was to therefore compare mandibular morphology in children with Pierre Robin sequence with children with Treacher Collins syndrome using three-dimensional analysis of computed tomographic scans. A retrospective analysis was performed identifying children with Pierre Robin sequence and Treacher Collins syndrome undergoing computed tomography. Three-dimensional reconstruction was performed, and ramus height, mandibular body length, and gonial angle were measured. These were then compared with those in control children with normal mandibles and with the clinical norms corrected for age and sex based on previously published measurements. Mandibular body length was found to be significantly shorter for children with Pierre Robin sequence, whereas ramus height was significantly shorter for children with Treacher Collins syndrome. This resulted in distinctly different ramus height–mandibular body length ratios. In addition, the gonial angle was more obtuse in both the Pierre Robin sequence and Treacher Collins syndrome groups compared with the controls. Three-dimensional mandibular morphometric analysis in patients with Pierre Robin sequence and Treacher Collins syndrome thus revealed distinctly different patterns of mandibular hypoplasiarelative to normal controls. These findings underscore distinct considerations that must be made in surgical planning for reconstruction.
From the *Hagey Laboratory for Pediatric Regenerative Medicine, Department of Surgery, Plastic and Reconstructive Surgery Division, Stanford University School of Medicine, Stanford, California; †Department of Surgery, Section of Plastic and Reconstructive Surgery, University of Michigan Medical Center, Ann Arbor, Michigan; ‡Division of Plastic and Reconstructive Surgery, David Geffen School of Medicine, University of California, Los Angeles, California; and §Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford California.
Received February 21, 2012.
Accepted for publication April 2, 2012.
Address correspondence and reprint requests to Derrick C. Wan, MD, Hagey Laboratory for Pediatric Regenerative Medicine, Stanford University School of Medicine, 257 Campus Dr, Stanford, CA 94305-5148; E-mail: firstname.lastname@example.org
M.T.C. and B.L. contributed equally to this article.
The authors report no conflicts of interest.