The fallacy of presumed superiority of proximally based versus distally based flaps.

As our knowledge of the origin of the cutaneous circulation becomes more precise, many preconceived notions continue to be abandoned. In this context, the general rule that distally based flaps are inherently inferior to proximally based flaps also should appropriately be challenged. To disprove this long-standing dictum, multiple abdominal flaps were simultaneously elevated in 15 Sprague-Dawley rats that included or excluded all possible combinations of musculocutaneous or axial skin perforators from each major source vessel (cranial or caudal epigastrics, superficial epigastric or lateral thoracic, respectively). These flaps were sequenced randomly in each rat to have superior (proximal) or inferior (distal) pedicles such that at least five flaps of each subtype were analyzed. Mean flap survival when the specific source vessel was retained uniformly was significantly greater than in all flaps where the source vessel had been excluded regardless of the orientation of the flap pedicle. All flaps with intact circulation had no significant difference in mean flap survival. Similarly, when normal flap circulation was excluded, no difference was observed in mean flap survival. Again, both these observations were true irrespective of the location of the flap base. Thus the major factor in determining flap viability was not whether its pedicle was proximally or distally based but rather the origin and quality of its intrinsic blood supply.