Viability of a 12-ring complete tracheal segment transferred in the form of a compound flap: an experimental study in dogs.

Abstract

There is a lack of an ideal substitute for the injured tracheal tissues. Autologous or homologous grafts and prostheses are inadequate because of their unreliable and nonviable nature for the reconstruction of a complete tracheal segment (CTS). We studied the viability of a 12-ring CTS transferred in the form of a compound flap from the sternohyoid muscle (SM) for tracheal reconstruction. Sixteen mongrel dogs of both sexes were divided into two groups of eight dogs each. In group I (control), a 12-ring CTS was removed and then reimplanted as an autograft. In group II, an SM flap was used to envelop four rings of the CTS to produce a compound CTS flap neovascularized by the SM (CTSNV). After 21 days, a 12-ring CTSNV, consisting of the four rings previously covered with SM, four rings above, and four rings below (without muscle covering), was sectioned and completely separated from the trachea. The CTS was then reimplanted at its original site, with the SM being the only vascular supply pedicle for the flap. The results were evaluated clinically and by macroscopic and microscopic examination of the surgical specimens. All the animals in group I (control) died or were killed by the first or second week because of necrosis and stenosis of the CTS graft. In group II, all animals were killed after 77 days of follow-up without showing any alteration in the CTSNV. We conclude that a compound 12-ring CTSNV flap remains viable and can be mobilized from the trachea without the risk of necrosis or stenosis.