Fetal cleft lip repair in lambs: histologic characteristics of the healing wound.

Sequential surgical procedures in cleft lip/palate (CL/P) patients result in scar formation that is believed to be associated with midface growth retardation. By use of a previously developed fetal lamb model, wound healing characteristics were investigated after in utero CL repair. It is hypothesized that scarless healing after fetal CL repair occurs without inflammation and scar formation. CL wounds were created in mid-second-trimester fetal lambs and either repaired in three layers (mucosa, muscle, and skin) or left unrepaired. Fetuses were then harvested at 7, 14, and 21 days postoperatively, and the wound site was examined microscopically. When created at 75 days' gestation (term = 145 days), fetal lamb CL wounds heal rapidly without inflammation and scar formation. By day 21 postoperatively, there was complete regeneration of skin, muscle, and mucosa, as well as epidermal appendages. With this model, it will be possible to compare the effects of scarless fetal CL repair with those of postnatal repair on midface growth.