Prefabrication of mucosa-lined flaps: a preliminary study in the pig model

There is a need in reconstructive surgery for flaps lined by nonkeratizing stratified squamous epithelium or mucous membrane. Applications could be found in nasal, oral, genital, and esophageal reconstruction and even in reconstruction of hollow intra-abdominal tubes. Prefabrication of lined flaps has so far been limited to a pretransfer grafting of split-thickness skin. However, in certain situations this does not satisfy the primary requirement of replacing "like with like." Also, the availability of donor sites for harvesting mucosa is limited. The present study involves prefabrication of mucosa-lined flaps without causing donor site morbidity. The study was carried out on six mini-Hartford pigs. Buccal mucosa was harvested from the cheeks; the sheet was divided into several smaller graft pieces of 1 to 2 cm2 area. These graft pieces were then applied to the deep fascia at a distance of 5 to 15 mm from one another, also to galea, and to the undersurface of skin flaps. The grafted area was isolated from the opposing surface with a silicone sheet or Marlex mesh. The grafts were allowed to take and, it was hoped, merge together to form a sheet graft of dimensions greater than those of the original. Two to 7 weeks after the initial grafting, the skin flap was elevated; the mucosal grafts were observed macroscopically for take and surface area and microscopically to confirm that the lining was indeed mucosa. The mucosa took well on both the fascia and galea and also on the undersurface of the skin; it enlarged in size, and the small pieces became confluent to form a single sheet. The increase in surface area varied from 33 percent at 11 days postgrafting to a maximum of 238 percent after 7 weeks. All pigs had positive cultures from the mucosa before implantation but only one developed gross infection leading to partial graft loss.