Afferent Arteriovenous Fistula in Thumb Revascularization

Abstract

A case of traumatic devascularized unviable thumb was revascularized using an afferent arteriovenous fistula. It proves again that this technique provides an alternative means of reimplantation/revascularization when no suitable artery for anastomosis is available in the devascularized/amputated part.Until now, only a few reported cases of successful reimplantation of the digits were done using afferent arteriovenous fistula.For the last decade, research studies have provided important physiological effects of flow reversal in the venous system. Most of the research works were encouraging. Recently a number of successful reimplantation/revascularization of digits and other composite structures were reported. Case ReportThe patient was a 28-year-old male admitted to King Khalid University Hospital with a devascularized right thumb. He had suffered a severe crush injury with a rotatory machine at the base of the right thumb over the volar aspect. The soft tissues were crushed for three-fourths of the whole of the base circumference. Both the digital vessels were completely severed and crushed. The ulnar digital nerve was cut and lacerated. The radial digital nerve was crushed but was intact.The proximal phalanx was shattered in multiple pieces (Figure 1). The flexor and extensor pollicis longus were intact. A small piece of the dorsal skin was lacerated but apparently intact with a dorsal vein. The thumb appeared dusky bluish and capillary refilling was absent. TreatmentThe proximal digital vessels were identified, but there were no distal digital arteries. A small branch of the radial digital artery supplying the dorsal skin was identified and anastomosed, but there was no improvement in circulation. Although anastomosis was patent, the thumb remained pale and cyanotic. After extensive searching, we found a small tortuous vena comitans on the ulnar side of the volar aspect distally and this was anastomosed with the ulnar digital artery. The thumb tip appeared pink on the table. The skin was approximated with only two sutures with minimum tension. There was good capillary refill.The small bony fragments and the distal half of the proximal phalanx were removed. The distal phalanx was fused to the remaining proximal phalanx in a "peg and socket" manner and fixed with Kirschner wire.The thumb remained pink and survived. Figure 2 shows the appearance of the revascularized thumb at three weeks postoperatively. DiscussionThe first arteriovenous anastomosis was originally described in 1896 by Francois Franck (Germann et al., 1987).1 But the details of surgical technique did not receive much attention until recently. A number of papers have described the concept of a flap with an afferent arteriovenous fistula. Some of these studies provided important but often conflicting information concerning the physiological effects of blood flow reversal in the venous system.

Options for thumb revascularization: our experience and literature review

“…Some authors have suggested creating an arteriovenous fistula. [5] This method is usually used when there is no suitable artery in the devascularized part. Better results are obtained when the volar veins are used for anastomosis and when there is less tension on the anastomosis between the proximal volar digital artery and the dorsal vein.…”