Thumb Reconstruction with First Dorsal Metacarpal Artery Flap: Salvage of the Flap after Venous Anastomosis to the Radial Artery

Selecting the most appropriate technique for thumb reconstruction depends on multiple factors, including level of injury, status of the remaining hand, age, occupation, overall health, and functional demands of the patient. Surgical treatment includes the use of local, regional, distant, or free flaps. In the practice, proximal-based first dorsal metacarpal artery (DMCA-I) is a successful thumb reconstruction method which provides optimal reconstructive and acceptable aesthetic outcome.

A 68-year-old male patient was admitted to the emergency room because of a traumatic defect of the thumb due to a home circular saw injury. The clinical examination showed full-thickness soft tissue loss with exposed bone without vital fractures. For defect coverage, a proximal-based DMCA-I pedicel flap was harvested for soft tissue reconstruction of the thumb. Accidently, the artery of the flap (DMCA-I) was severed at the level of metacarpophalangeal joint. The accompanying vein of the flap was intact. For salvage of the flap, we chose a vein graft interposed by “end-to-side” anastomosis with the radial artery at the level of the snuff box and distally with an “end-to-end” anastomosis to a superficial subcutaneous vein of the flap ([Fig. 1]). After tourniquet release, we observed intact blood supply to the flap. No venous congestion was noticed and the postoperative course was uneventful. Follow-up visits in our outpatient department showed a good functional and aesthetic result ([Fig. 2]).

Fig. 1 Salvage of the flap with the vein graft anastomosed between the superficial vein of the flap and the radial artery (end-to-side).

Fig. 2 Appearance of the flap site at a postoperative visit in the clinic.

Extensive palmar defects of the thumb, with the exposure of tendons or bones, are challenging reconstructive problems and surgical treatment includes the use of local, regional, or free flaps. These options can include, but not limited to, Moberg homodigital advancement flaps, littler heterodigital neurovascular flaps, and DMCA-I flaps. Due to the extensive defect, we chose a flap from the dorsum of the index finger proximally based on the DMCA-I. This DMCA flap with a cutaneous pedicle was first described by Hilgenfeldt in 1961 and thereafter by Holevich in 1963.[1] The island flap solely supplied by a vascular pedicle consisting of the DMCA-I and concomitant veins was reported by Foucher and Braun in 1979.[2] The DMCA-I arises from the radial artery in the first intermetacarpal space, just distal to the tendon of the extensor pollicis longus. The artery divides into the radial branch to the thumb, the intermediate branch to the first web space, and the ulnar branch to the index finger. In 90% of cases, the DMCA-I parallels the second metacarpal bone distally. In 10% of cases, it is found in the midline of the triangle that is formed by the first commissure. The DMCA-I can be localized in a superfascial (57%) or subfascial (43%) location. At the neck of the second metacarpal bone, a small anastomosis to the palmar arterial system can be found. This branch must be ligated or cauterized when raising the flap.

In general, the DMCA-I flap is considered a safe and reliable flap. Rare complications of this flap are related to the preoperative condition of the patient with atherosclerosis or intraoperative problems like technical errors, or postoperative situations with kinking or pressure on the pedicle. Preparation of the vascular pedicle at the neck of the second metacarpal neck can be challenging. Iatrogenic injury of the pedicle at this point leaves the surgeon with the decision for an alternative flap coverage such as homodigital flap, free flap, or salvage of the flap. Reconstruction of digital defects using venous flow-through flaps has been described in the literature but remained unpopular owing to various levels of perfusion and subsequent ischemia. In 1981, Nakayama et al reported on arterialized venous free flaps.[3] Further reports on the clinical application of this technique demonstrated some failure due to arteriovenous shunting. Kamei and Ide[4] reported that inflow vessel and outflow vessel should be different or separated to increase performance and flap survival. Similarly, we used a cutaneous vein for inflow and the concomitant veins in the original pedicle as outflow. Therefore, our flap was classified as a Chen type III arterialized venous flow-through flap as best fit. Initially, Chen classification type III and IV were described for venous free flaps and type II (B) for pedicled flaps.[5] With regard to the Goldschlager classification, we propose a type III (C_{1 retrograde} P₂) as we incorporated one discontinued arterial afferent vessel and two efferent concomitant veins.[6]

Despite the fact that proximal-based DMCA-I flap is routinely performed for soft tissue reconstruction of the thumb, unfortunate iatrogenic injury can occur to the arterial supply of the flap. Applying knowledge on venous flow-through flaps, we were able to salvage the flap. Arterialization of the flap was performed with inflow via a cutaneous vein and efferent venous drainage of two concomitant veins of the original vascular pedicle.

Publication History

Article published online:
20 August 2020

• References

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• 2 Foucher G, Braun JB. A new island flap transfer from the dorsum of the index to the thumb. Plast Reconstr Surg 1979; 63 (03) 344-349
• 3 Nakayama Y, Soeda S, Kasai Y. Flaps nourished by arterial inflow through the venous system: an experimental investigation. Plast Reconstr Surg 1981; 67 (03) 328-334
• 4 Kamei K, Ide Y. The pedicled arterialized venous flap. J Reconstr Microsurg 1993; 9 (04) 287-291
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• 6 Goldschlager R, Rozen WM, Ting JW, Leong J. The nomenclature of venous flow-through flaps: updated classification and review of the literature. Microsurgery 2012; 32 (06) 497-501