This study is designed to describe and illustrate distal thumb reconstruction using a reverse-flow island flap from the thenar eminence for treatment of partial tissue loss. Previous dye-injection studies by the same group identified the cutaneous territory supplied by the superficial palmar branch of the radial artery. This artery is located over the superficial aspect of the abductor pollicis brevis and opponens pollicis muscles. Importantly, the authors claim to have found that the superficial palmar branch of the artery communicates with another palmar artery in 60% of their specimens. The reverse-flow flap was based on this anastomosis. Earlier dye studies found that the average diameter of the superficial palmar branch of the artery was 1.4 mm. Palpation and Doppler examination of the superficial palmar artery was performed in pre-operative planning. The reverse thenar flap was then designed with the proximal margin of the thenar eminence as its proximal boundary, the ulnar border radial to the FCR tendon to avoid injury to the palmar cutaneous branch of the median nerve, and the radial border approximately 3 cm radial to this in an effort to center the arterial perforator in the flap. No mention is made in describing the technique of venous perforators, venae comitans, or subcutaneous venous tissue. The authors very briefly mention that the flap can be ?made sensible by the palmar branch of the superficial radial nerve.? However, they do not describe or depict how this is accomplished in a long retrograde flap. Six patients are described who underwent the procedure. Ages ranged from 29-63 yrs. Flap size ranged from 3 x 2 to 5 x 3.5 cm. All flaps survived without further surgery. Donor site morbidity was minimal, and all patients were satisfied with their cosmetic results. In one ?sensory flap? moving 2-pt. discrimination was reported at 5mm.
This is yet another of the numerous recent descriptions in the literature of useful flaps based on small arterial pedicles in the hand. This flap is an extrapolation of earlier work. The authors have done well to identify and characterize the arterial supply to the cutaneous territory of this flap. Their one clinical example shows an excellent cosmetic result; the remaining five patients reported acceptance of their results. However, no critical analysis of other important parameters is listed, other than moving 2-pt. discrimination. The sample size is too small to allow for statistical comparison of the results. This report provides the basis for further expansion of the compendium of local flaps to the hand for coverage of relatively small but critical defects. However, a number of important questions remain unanswered. First, what is the utility of a reverse-flow island flap in which the vascular pedicle is present in only 60% of the cases? With a mean arterial diameter of only 1.4 mm, how reliable is pre-operative evaluation of this connection? The likelihood of raising an avascular flap, despite careful pre-operative assessment, seems unacceptably high. Second, how exactly is this flap innervated by using the superficial radial nerve, which travels antegrade as the flap travels retrograde? Was this taken as a free graft segment? Was there a distal anastomosis? This remains puzzling. Lastly, as stated, there is no assessment of important functional criteria, such as pinch strength in the reconstructed thumb (versus normal controls or compared with alternative methods of repair), functional outcome measures of grasp or dexterity or even restoration of length and volume by measurement. All of these parameters should be evaluated before considering this flap a viable method of closure for critical thumb defects. Nonetheless, this report does serve as a very useful stimulus for further investigation.
Journal of Reconstructive Microsurgery