Faculty Bibliography

The structure of the submental platysma muscle was evaluated in 20 preserved cadavers. Four distinct patterns were identified, depending on the pattern of merging of the right and left platysma bundles. Fifteen percent of cases showed a complete platysma diaphragm submentally, while in the other 85% there was some degree of midline dehiscence. In the 85% of cases where right and left fibers merged or crossed to form a V or U shape, the apex of the V or U was measured relative to the chin point. The distance between right and left fibers was measured at two locations posterior to the chin point. The width of the midline dehiscence (when present) was 6-24 mm (mean 11.8 mm) 1 cm posterior to its apex and 10-44 mm (mean 20.00 mm) 2 cm posterior to the apex. The wider and more divergent the dehiscence and the more U-shaped the dehiscence between left and right platysma bundles, the greater may be the tendency to a 'turkey gobbler' deformity with inadequate medial support for the skin and subcutaneous tissues

This study examines the histologic and biochemical features of wound healing in a cleft lip model in the mid-third-trimester fetal rabbit. At days 1, 2, and 4 after the procedure, control, unrepaired, and repaired fetal heads were obtained, sectioned, and stained for histologic examination. The localization of hyaluronic acid in the wound was documented using a cartilage-derived hyaluronic acid-binding protein. In both repaired and unrepaired wounds, the fetal cleft healed without inflammatory cell infiltration or scar formation. Six months after birth, the repaired cleft showed complete regeneration of muscle across the wound and the collagen fibers were of normal density and orientation. Decreased hyaluronic acid deposition was observed in unrepaired clefts as compared with adjacent tissue; no such difference was detected in repaired clefts. Our findings support the hypothesis that a cleft lip repaired in utero heals without the scarring that accompanies postnatal repair. This may explain the lack of maxillary growth restriction after in utero cleft lip repair.

We have previously described a model for in utero cleft lip repair in rabbits. Cleft lip and alveolus (CL) were created in fetal rabbits at 24 days gestation (term, 31 days). In this study, postnatal maxillary growth was evaluated in three groups of animals: 1) unoperated controls, 2) unrepaired CL, and 2) repaired CL. The animals were killed at 4, 12, and 26 weeks after birth. Direct cephalometry was performed on dry skulls to evaluate premaxillary width, anterior maxillary length and width, and posterior maxillary width. The results of this study indicate that rabbits that undergo an in utero CL procedure, with or without repair, exhibit no significant decrease in maxillary length and width when compared with controls.