POSTERIOR INTEROSSEOUS REVERSE FOREARM FLAP - EXPERIENCE WITH 80 CONSECUTIVE CASES

The results of an anatomic investigation performed in 40 fresh cadaver specimens and 80 consecutive clinical cases of the posterior interosseous reverse forearm flap are reported. It was observed that there is a choke anastomosis between the recurrent dorsal branch of the anterior interosseous artery and the posterior interosseous artery at the level of the middle third of the posterior forearm. Ink injections through a catheter placed in the distal part of the anterior interosseous artery stained the distal and middle thirds of the posterior forearm, but the proximal third remained unstained; this secondary territory cannot be captured through the choke anastomosis between the anterior interosseous artery and the posterior interosseous artery. Intravital fluorescein injection into the distal arterior interosseous artery revealed (under ultraviolet light) that the distal third of the posterior forearm is irrigated by direct flow through the recurrent branch of the arterior interosseous artery (the traditionally called distal anastomosis of the interosseous arteries). Therefore, we can assume that the blood flow is not reversed when the so-called posterior interosseous reverse forearm flap is raised. From this point of view, this flap could be renamed as the recurrent dorsal anterior interosseous direct flap; however, the classical name is maintained for practical purposes. From the venous standpoint, the cutaneous area included in this flap belongs to an oscillating type of venous territory and is connected to the deep system through an interconnecting venous perforator that accompanies a medial cutaneous arterial branch located at 1 to 2 cm distal to the middle point of the forearm. It was observed in clinical cases that the posterior interosseous reverse forearm flap can be safely raised with this ''medial pedicle.'' Flaps designed on the proximal third of the posterior forearm suffered tissue loss even with incorporation of the large proximal cutaneous branch of the posterior interosseous artery. It is advisable to restrict flap design distal to the proximal quarter of the forearm. Four flaps were lost in our series of 80 clinical cases, and we believe that this was due to technical error. Functional morbidity of the donor area is minimal.