Midline skeletodental morphology in holoprosencephaly.

OBJECTIVE: The purpose of the present study was to analyze histologically the midline structures in a human fetus with holoprosencephaly and a single median maxillary central incisor. METHODS: A human male fetus, CRL 137 mm, postconceptional age 18 weeks, with a diagnosis of holoprosencephaly, the cebocephalic type (one nostril), and alobar brain development, was investigated. After radiography, the cranial midline structures were examined histologically. RESULTS: The histological examination revealed partial absence of the intermaxillary suture (in the region anterior to the central incisor), absence of the internasal suture, and partial absence of the metopic suture (caudal part). A single midline nasal bone was observed instead of two bilateral nasal bones, and a midline maxillary central incisor was found instead of two bilateral incisors. A short nasal septum, absence of crista galli, and partial absence of cartilaginous tissue anterior to the sella turcica in the region of the presphenoid bone were recorded. CONCLUSIONS: The study shows that in the affected fetus, there were malformations of midline structures anterior to the sella turcica comprising suture development and cartilage development.

Transverse displacement of the proximal segment after bilateral sagittal osteotomy.

PURPOSE: The aim of the present investigation was to evaluate the transverse displacement of the proximal segment and ramus rotation after a bilateral sagittal osteotomy (BSO) with rigid internal fixation (RIF) using bicortical LAG screws. PATIENTS AND METHODS: We conducted a retrospective review of 37 patients (14 males and 23 females, age range of 14 to 55 years) who underwent a mandibular advancement with BSO and RIF. Posteroanterior and lateral cephalometric radiographs were obtained 1 to 8 weeks before and 1 to 4 weeks after surgery. The transverse displacement and angulation of the proximal segments after surgery were measured on posteroanterior radiographs, using the best-fit method. The amount of mandibular advancement was compared with the amount of transverse displacement of the proximal segments. RESULTS: In the 1 to 4-week postoperative period after a BSO, 36 of 37 subjects showed an increased transverse intergonion distance (5.6 mm) (P <.0001) and 35 of 37 patients showed an increased transverse interramus width (3.3 mm) (P <.0001). No correlation was found between mandibular advancement and transverse displacement of the proximal segment. CONCLUSIONS: The study results indicate that transverse displacements of the proximal segments occur with BSO and RIF. The clinical impact on temporomandibular joint symptomatology or surgical relapse with such displacement was not assessed in the study. Future studies that address these issues may help to determine whether there is an association between proximal segment displacement and surgical relapse, temporomandibular dysfunction, or both.