Tympanic Skin Grafting and Reconstruction of the Middle Ear Sound-Conduction Mechanism

Physiology of Tympanic Skin Grafting

• A tympanic skin graft stretches across the middle ear. Its bed lies peripherally and consists of the denuded rim of drum, annulus and adjacent canal wall. It flourishes after endothelial vascular buds grow from the bed out into the graft and make continuity with the graft blood vessels to form its permanent blood supply. This occurs about the 4th to 10th day.

Fig. 1.—Vascular supply of skin, demonstrating necessity of three-fourth-thickness to full-thickness skin graft in order to obtain adequate vascular supply for tympanic graft.

II.

• tympanic skin graft survives the first four days because of

  1. A plasmic circulation diffusing extracellularly into the graft. This can nourish only the part of the graft directly over the bed.

  2. An immediate intravascular circulation of blood from some of the myriad severed graft capillaries which come in contact with some of the myriad severed