Location and length of arteriovenous fistulas around axial-pattern skin-flap pedicles

The importance of the location of a surgically-created arteriovenous fistul a around the pedicle (both distal and proximal) on the viability of rat ski n flaps was investigated. The animals were randomly divided into four group s. Group I included bilateral standard island groin flaps. The right side f lap was used as a control. On the left side, after elevation of the flap, a n X-type arteriovenous fistula greater than 1 mm (up to 2 mm) in length was created distal to the pedicle, and just before the bifurcation of the comm on femoral vessels. In Group 2, the flap was an axial-pattern medially-base d peninsular flap, including the same vessels. In this group also, two flap s were elevated bilaterally, and the right side was used as a control; on t he left side, an X-type arteriovenous fistula the same length as in Group I was also created distal to the pedicle. In both groups, all other branches of the common femoral vessels were kept intact. In a second part of the st udy, two other animal groups were used to clarify the importance of the len gth of the arteriovenous fistula on the viability of skin flaps. In Group 3 , the model was the same as in Group 1, but the fistula was 1 mm in length. In Group 4, the length of the fistula was 1 mm, and its location was on th e common femoral vessels proximal to the pedicle, using the same flap model . Flow values were measured repeatedly using a laser Doppler flowmeter. His topathologic studies were also done. There are three important points arising from these studies. 1). The locati on of an X-type arteriovenous fistula around an island skin flap pedicle se ems to be more important than diameter. An arteriovenous fistula proximal t o the pedicle is more hazardous than an arteriovenous fistula distal to the pedicle, regarding island skin-flap viability. 2). However, the length of the fistula is also important, and an arteriovenous fistula distal to the p edicle, with a sufficiently long length, is not devoid of harmful effects. It is also clear that the larger the fistula, the greater the systemic effe cts. 3). An island skin flap with an arteriovenous fistula distal to its pe dicle might be a useful model to study the relationship between skin-flap v iability and edema formation.