Role of Perivenous Areolar Tissue in the Viability of Island Flaps with an Exclusively Venous Pedicle

ABSTRACT

For the venous flap to survive, it apparently needs to be a flow-through of venous blood.1 Nevertheless, controversy remains, regarding the fact that an island flap based on a terminating venous pedicle is capable of maintaining viability.2-15 This study was designed to investigate the role of perivenous areolar tissue in the viability of island flaps with an exclusively venous pedicle in the rabbit ear model as described by Inada et al.16 Ten groups of flaps were studied Group A-flaps based on a proximal venous pedicle; group B-flaps based on a distal venous pedicle; group C- nonvascularized grafts; each subgroup A1-, B1-flaps with perivenous areolar tissue; each subgroup A2-, B2-flap which was skeletonized pedicle; each subgroup A3-, B3-flap was same as A1-, B1-flap, which was sutured over a silastic sheet; each subgroup A4-, B4-flap with a skeletonized venous pedicle sutured over a silastic sheet; subgroup C1-control, placed directly on bed; subgroup C2-control which was sutured over a silastic sheet. Groups A3, A4, B3 and B4 had 20 flaps and the remaining groups had 10 flaps each. Flaps in group A1, A3, B3 had total survival. In groups A4, B4, C2, no flaps were survived. The survived flaps in groups A3 and B3 had tissue oxygen content values between those of arterial and venous levels. Histological examination of the pedicle of survived flaps in groups A3 and B3 showed small vascular channels present in the areolar tissue surrounding the venous pedicle. Static and dynamic computerized radioactive tracer experiments showed that the survived flaps in groups A3 and B3 were promptly perfused and drained through their pedicles. This study confirms the importance of the perivenous areolar tissue for survival of the venous skin flap in the rabbit ear model.