Floor plan - 2013 Annual Meeting - American Association for Hand ...

Modified Allen's Test Using Near Infrared Spectroscopy: Clincal and Anatomic Study
Institution where the work was prepared: University of Texas Southwestern Medical Center, Dallas, TX, USA
Daniel A. Hatef, MD; Dallas Alvey; Li Ngov; Michel Saint-Cyr; Spencer A. Brown; Rod J. Rohrich; University of Texas
Southwestern Medical Center
INTRODUCTION:
A dogma of hand surgery instructs that the dominant arterial supply to the hand is the ulnar artery. This has some serious clinical implications,
as reconstructive surgeons use the radial forearm flap to repair defects all over the body, and cardiac surgeons often harvest
the radial artery for use as a graft in coronary bypass surgery.
METHODS:
Near Infrared Spectroscopy was used to assess tissue oxygen saturation (St02) in the second and fifth digit, while performing the modified
Allen's test, in 30 hands of 15 subjects. Measurements were recorded and statistically analyzed. A cadaveric study was undertaken
using 6 upper extremities, to confirm the findings of this and previous studies. Radiopaque barium was injected into the brachial
artery to demonstrate the vasculature of the forearm and hand. The arms were then scanned using a CT scanner, and the images were
reconstructed and analyzed using TeraRecon Æ imaging software.
RESULTS:
Baseline St02 readings were variable (range 39 to 90; Mean = 64.43; St. Dev. = 13.07). Two hands, of the same patient, demonstrated
clear ulnar dominance; one hand demonstrated radial dominance. Of note, two hands had normal Allen's tests, but appeared to have
radial dominance to the index. The results of the cadaveric investigation demonstrate that 2 of the 10 upper extremities had incomplete
filling of the superficial arch. The ulnar digital artery was seen to be dominant in every index digit; this was a branch of the palmar
metacarpal artery off of the superficial palmar arch in 8 specimens, and the terminal branch of the radial artery in 2 specimens.
DISCUSSION:
This study shows that there is no one dominant blood supply to the hand. This study demonstrates the importance of diligent use of
the Allen's test preoperatively, and in any patient with questionable result, it is recommended that the radial artery not be sacrificed.
Some hands may have radial dominance to the index, but an anatomical reason for this was not confirmed through cadaveric investigation.
Near infrared spectroscopy demonstrated extremely variable St02 readings. It cannot be concluded that use of near infrared
spectroscopy aids in improving the sensitivity of the Allen's test.
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