[The autotransplanted tracheas wrapped in united muscle flap of the neck: an experiment].

OBJECTIVE

To investigate the way of revascularization of donator's trachea wrapped in united muscle flap.

METHODS

Using fiberoptic bronchoscopy, histopathology and microangiography, we evaluated the tracheal mucosal blood flow, the survival rate, the percentage of patency, and the graft viability of autograft tracheas with varying lengths wrapped in one-sided sternocephalic muscle flap and two-sided sternohyoid-sternothyroid muscle flap and autograft tracheas with the length of 5 rings without wrapped in muscle flap in 32 dogs.

RESULTS

In the tracheal autograft wrapped in the united muscle flap group with a length less than 4 centimeters, the submucosal blood flow of graft could be detected by laser blood flowmetry one week after transplantation, and it reached 60% of the normal, which had no significant difference between the place near the site of anastomosis and the middle part of the graft. Dense vessels could be found to grow from the wrapped muscles into the autografted trachea by microangiography. Histopathological examination demonstrated that the structure of the autograft was the same as what it originally was. the inner surface of the autograft was covered with pseudostratified columnar ciliary epithelia, and no necrotic tracheal cartilages were found. Every autograft could survive over long time. However, at 1 week, most mucous membrane in the middle part of the graft with length over 4 cm was in gray or in pale; hyperemia, edema, and haemorrhage were found near the site of anastomosis. Mucosal blood flow measured by laser blood flowmetry in the middle part of the graft was significantly less than that near the site of anastomosis. Malacia, dissolution or granulation hyperplasia occurred in midportion of the major grafts shortly after transplanatation. As for those autografted trachea without wrapping in muscles flap, mucous membranes turned black one week after the transplantation and all dogs died of graft necrosis later.

CONCLUSION

One-sided sternocephalic muscle flap and two-sided sternohyoid-sternothyroid muscle flap can provide blood for the graft and the grafted trachea can survive for a long time.