Pierre Robin Sequence and Treacher Collins Hypoplastic Mandible Comparison Using Three-Dimensional Morphometric Analysis

Abstract

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 to children with Treacher Collins syndrome using three-dimensional analysis of computed tomography (CT) scans. A retrospective analysis was performed identifying children with Pierre Robin sequence and Treacher Collins syndrome receiving CT scans. Three-dimensional reconstruction was performed and ramus height, mandibular body length, and gonial angle were measured. These were then compared to control children with normal mandibles and to 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 while 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 hypoplasia relative to normal controls. These findings underscore distinct considerations which must be made in surgical planning for reconstruction.

Mapping the Mandibular Lingula in Pierre Robin Sequence

“…Regarding the dimensions of the PRS mandible, as expected, mandibles of patients in group 1 displayed globally smaller dimensions compared with nonaffected counterparts due to primary pathology and age: They had a significantly shorter horizontal ramus (26.58 versus 40.62 mm, P ¼ 0.001), shorter vertical ramus (16.05 versus 23.04 mm, P ¼ 0.003), and narrower vertical ramus 39 The clinical significance of ramus width is uncertain. It has been reported as a potential parameter for analysis of malocclusion, 40 and differences in ramus dimensions have been studied in the context of masseter muscle insertion and resulting masticatory function.…”

“…The gonial angles of all types of micrognathic mandibles have been found to be more obtuse compared to normal mandibles. 39,42,43 The clinical significance of this, both in terms of cause and consequence, is not fully understood. The shape of the mandibular base, especially the gonial angle, correlates with the function and shape of the muscles of mastication.…”

“…Within the PRS population, syndromic patients have shorter mandibular length, shorter ramus height, smaller mandibular body, and more obtuse gonial angle. 39,43 Further complicating the picture, opinions differ regarding ''catch up'' growth of the mandible as a whole, as well as specific subunits (ramus versus body) during infancy and childhood. 51 In addition, there is further variability in mandibular development in syndromic patients, with airway obstruction not as consistently alleviated by distraction osteogenesis.…”

The combined use of surgical rehearsal platform and BrainLab navigation for mandibular osteotomy in Nager syndrome

“…All of these syndromes share commonality in that specific genetic alterations affect key craniofacial developmental pathways leading to micrognathia, glossoptosis, and subsequent air obstruction [9,10]. Therefore, the goals of treatment for these children focuses on breathing and feeding and optimizing growth and nutrition.…”

Refinamento fenotípico da disostose mandibulofacial tipo Bauru

“…De acordo com os autores, a alteração mandibular é responsável pelo perfil facial convexo observado na STC. Chung et al (2012) …”