Arterialization of the Venous Network as a Solution to Obstructed Arterial System During Replantation

INTRODUCTION

Between the years of 1978 and 2010 there were 2240 replantations and revascularizations performed at the Department of Plastic and Aesthetic Surgery, St. Anne’s University Hospital Brno, including 1918 fingers, 210 hands, 78 forearms, 13 arms, 8 feet, 5 scalps, 4 ears, 2 noses and one lip. During replantation the arterial and venous network is reconstructed by anastomoses of arteries and veins. In our practice we have used arterialization of the venous network in six cases of replantations. Arterialization was used in three cases in replantation of the distal phalanx of a finger and in one case of ear replantation (1). In these four acral amputation cases the amputated parts lacked usable arteries, and the arteriovenous anastomosis was the only solution to restore circulation in the amputated part. Arterialization of the venous network was also used in two cases of thumb replantation when circulation was not restored despite patent arterial anastomoses. We will use these two cases of thumb replantation to demonstrate the method of venous network arterialization as a last resort in cases when, despite patent arterial anastomosis, blood circulation cannot be restored in the amputated finger.

CASE STUDY

Case #1

41-year-old patient sustained total amputation of the left thumb in the distal half of the proximal phalanx while working with a circular saw (Fig. 1). The patient had no significant past medical history, no regular medication and no drug allergies. Axillary block was used to complete the thumb replantation. Anastomosis of the ulnar digital artery was performed during the replantation. Blood circulation in the finger was restored and the procedure was completed with anastomosis of two dorsal veins. Prior to completion of the venous anastomoses the finger became ischemic despite the patent arterial anastomosis. Therefore, we also performed anastomosis of the radial digital artery. However, the finger still did not get any blood supply. To exclude possible hidden damage to the blood vessels there was an extensive resection performed in both stumps of the ulnar digital artery and the segment was replaced by a venous graft harvested from the forearm (2). The anastomoses were patent, but the perfusion of the thumb remained absent. As a last resort to restore blood supply in the amputated part we have chosen the method of venous network arterialization. At the level of amputation we performed an anastomosis of the radial digital artery of the thumb stump with the dorsal vein of the amputated part. Good blood supply of the thumb was gradually restored within four hours after this anastomosis. Total ischemia time was 10 hours, of which 6 hours was cold ischemia. During the surgery was administered heparin intravenously at a total dose of 5000 IU, low molecular weight heparin was administered subcutaneously in the dose of 4000 IU and 6% hydroxyethylcellulose intravenously. Magnesium sulphuricum was repeatedly applied periarterially. In the postoperative period was subcutaneously administered low molecular heparin, 6% hydroxyethylcellulose continually IV and anti-aggregants orally. Six months after the replantation was performed tenolysis of the flexor pollicis longus tendon. Function of the thumb was considered very good (the range of motion in the MP joint was 80°, the range of motion in the IP joint was 40°). After 10 months was the two-point discrimination restored to 4 mm. The patient was very happy with the function of his thumb (Fig. 2).

Case # 2

62-year-old patient with a history of hypertension, diabetes and ischemic heart disease sustained total amputation of the thumb on his dominant right upper extremity. The thumb was amputated in the proximal phalanx near to the MP joint. We performed replantation of the thumb under general anaesthesia. During the replantation we performed anastomosis of the ulnar digital artery and two dorsal veins. The thumb got blood supply, however, the capillary refill on the replanted finger was sluggish. In the early post-operative period the thumb became ischemic despite heparinization. During revision we found thrombosis of the ulnar digital artery. We resected the anastomosis, performed thrombectomy and administered heparin flush. The ulnar digital artery on the stump was spurting bright blood after the flush. On the amputated part, however, it was very difficult to flush and there was increased resistance in the periphery. Again we performed an anastomosis of the ulnar digital artery but the thumb did not get good supply despite the patency of the arterial anastomosis. On the radial side of the amputated part was the digital artery pulled out, but the vena comitans was well preserved. Therefore we performed an anastomosis of the radial digital artery of the thumb stump with the vena comitans on the radial side of the amputated part. After this anastomosis the blood supply in the finger gradually increased within two hours (Fig. 3). Total ischemia time of the amputated thumb was 12 hours. During the surgery we administered IV heparin and repeatedly periarterially magnesium sulphuricum. In the post-operative period the patient received continuous IV heparin and later low molecular weight heparin subcutaneously and oral anti-aggregants. After six months we evaluated the function of the thumb and found it satisfactory (the range of motion in the MP joint was 30°, in the IP joint was 0°). In twelve months was the two-point discrimination in the thumb restored to 5 mm. The patient was happy about the function of his thumb and did not wish to proceed with tenolysis of the flexor pollicis longus tendon (Fig. 4).

DISCUSSION

Although finger replantation has nowadays been routinely performed (3, 4), even with technically precise microvascular anastomosis of the intact stumps of the vessels, there are additional risks such as thrombosis, arterial spasms, or micro-circulation failure. Replantation of the very distal parts is particularly problematic (1, 5, 6). In some cases even with patent anastomosis and intensive support with conservative therapy (vasodilators, anticoagulants) the blood supply cannot be restored, because the arterial system peripherally to the anastomosis is obstructed. The reason could be detachment of the intima or contusion of the blood vessel anywhere distally to the anastomosis or also thrombosis at the level of the arterioles. If the amputated part does not get blood supply due to prolonged ischemia and subsequent damage to the micro-circulation, the result can be no-reflow phenomenon.

If pressure in a vein is increased several times, reaching the level of the arterial pressure, the characteristics of the venous valve system allows reverse flow and restoration of the micro-circulation through A-V shunts or vasa vasorum. Due to the multiplicity of veins, one of them may be used for oxygenation of the tissues and the others for venous return (7, 8, 9).

Francois-Franck first described arteriovenous anastomosis as early as in 1896 (10). However, the use of arteriovenous anastomosis in clinical practice during replantations and free vascularized tissue transfers was not reported until the 1980s and 1990s (1, 11, 12, 13, 14).

Despite the controversy of the blood flow (AV shunts, vasa vasorum, incompetence of venous valves) the use of arterialized venous flaps became widespread in clinical practice (15, 16, 17, 18, 19). Arteriovenous anastomosis may be used successfully in cases where there is significant damage to arteries in the amputated parts or in cases when patent arterial anastomosis does not lead to restoration of blood supply of the finger and we presume damage at the level of the arterial and arteriolar network distally to the anastomosis, for example intimal damage or presence of microthrombi (20).

In our first case the amputated thumb did not get proper blood supply despite patent anastomoses of both digital arteries. We assumed more extensive microscopical injury of the digital arteries. Therefore we performed more extensive resection of both stumps of the ulnar digital artery and replaced the missing segment with a venous graft harvested from the volar side of the wrist (2). When the lack of blood supply persisted, and even administration of IV heparin did not help, we assumed that the cause of persisting ischemia was a spasm of the digital arteries. Therefore we instilled magnesium sulphuricum to the periarterial area (21). However, even after the administration of magnesium sulphuricum the blood supply did not improve, and we chose arteriovenous anastomosis as a last resort.

In our second case the thumb received blood supply after surgery, but in the early post-operative period it became ischemic. During a revision we found thrombosis in the area of the arterial anastomosis. After resection of the anastomosis and removal of the thrombi there was significant resistance observed during a flush of the peripheral part of the artery, which is a sign of damage in the blood network. In the amputated part the artery was missing on the other side, and therefore as the last resort we chose arteriovenous anastomosis.

The amputated thumbs received good blood supply after arterialization of the venous network, which allowed us to exclude the no-reflow phenomenon as the reason why the standard methods failed to restore blood supply of the fingers.

Conclusions

The results were not different from the conventionally performed replantations in both cases of thumb replantation using venous arterialization. Our experience shows that the method of the venous network arterialization may be successfully used in cases where the surgeon performing the replantation has difficulties because the arteries in the amputated parts are significantly damaged or missing, or when the conventional methods do not result in restoration of blood supply of the amputated body part due to a blockage of the arterial system.

Address for correspondence:

Tomáš Kubek, M.D.

Department of Plastic and Aesthetic Surgery,

St. Anne’s University Hospital Brno

Berkova 34

612 00 Brno

Czech Republic

E-mail: tomas.kubek@post.cz