Lower extremity allen test (LEAT) in reconstruction
Evan Garfein, MD, Nicholas Haddock, MD, Jamie Levine, MD, Pierre Saadeh.
NYU School of Medicine, New York, NY, USA.
BACKGROUND: The Allen test was first described in 1929 by Dr. Edgar Allen at the Mayo Clinic. The test originally involved simultaneous testing of both hands to assess the radial artery contribution to distal circulation. The test was later modified to diagnose the relative contribution of the ulnar and radial arteries of each hand to its distal perfusion. We modified the Allen test concept to investigate the relative contribution of the posterior tibial artery to distal perfusion of the lower extremity in cases of reconstruction for trauma.
METHODS: The test is performed with the patient supine. A handheld doppler is used to locate the first dorsal metatarsal artery in the first webspace. The posterior tibial (PT) pulse is palpated posterior to the medial malleolus and compressed. The dorsalis pedal (DP) pulse is simultaneously palpated and compressed. A persistent signal indicates collateral flow through the peroneal artery (PA). If the signal is extinguished, the DP artery is decompressed. Recommencement of a signal indicates dependence on the DP for perfusion of the distal foot. If releasing pressure on the DP does not result in return of signal, the PT is released. Resumption of a distal signal under these conditions indicates that the distal foot is dependent on the PT for perfusion. PA contribution to either the DP or PT may be significant but does not alter the functional conclusions of the test.
RESULTS: We report a case in which angiography failed to predict reliance on the PTA. In this case, performance of the LEAT led to alternative recipient vessel choice.
CONCLUSIONS: This test is simple to perform and provides a valuable adjunct to angiographic data. If a single vessel is responsible for distal perfusion, the reconstructive surgeon must plan to use either an alternative recipient vessel or an end-to-side anastomosis.