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Preoperative ultrasound Doppler study and clinical correlation of free posterior interosseous flap.

BACKGROUND
Conventional pedicled posterior interosseous flap has a relatively high rate of partial flap loss which may result in ultimate failure to provide coverage of this important structure. The goal of this study was to delineate the posterior interosseous flap as a reliable free tissue transfer.


METHODS
From 1991 to 1995, 34 patients undergoing free posterior interosseous flap had preoperative Doppler mapping to determine the point of emergence of the skin perforators of the posterior interosseous artery. This finding was correlated intraoperatively with the number of perforators nourishing the posterior interosseous flap. The anatomic variations in the posterior interosseous artery were also identified.


RESULTS
These results showed (1) the main skin perforator was consistent and reliable in all of the posterior interosseous flaps both in the preoperative Doppler evaluation and intraoperative findings; (2) the main skin perforator arose from the posterior interosseous artery, the ascending interosseous recurrent artery or the common interosseous artery in 26 cases (76%), 6 cases (17.6%) or 2 cases (5.9%) respectively; (3) the success rate with the use of the free posterior interosseous flap was 97% without any partial flap loss.


CONCLUSION
It is concluded that the free posterior interosseous flap is a reliable flap with adequate arterial flow from constant main skin perforators and large antegrade venous drainage. A less reliable distally based pedicle flap can be changed into a reliable free flap, with the aid of preoperative non-invasive Doppler evaluation. This principle could be applied in the design of other "free skin perforator flaps".