Use of anterolateral thigh free flap for reconstruction and salvage of thoracic limb caused by an arteriovenous malformation

Abstract

Vascular arteriovenous malformations originate during the early stages of embryonic development and generally grow progressively, especially during adolescence and pregnancy. Limb salvage using microsurgery is presented, in a patient with an arteriovenous malformation who was initially a candidate for limb amputation. En bloc resection of the arteriovenous malformation of all segments with extended brachial approach and the cutaneous component was performed, with an anterolateral thigh free flap for the lateral reconstruction of the hand.

Background

Vascular arteriovenous malformations originate during early stages of embryonic development and generally grow progressively, especially during adolescence and pregnancy.¹ They consist of arteriovenous microfistulas through a vascular nest, which can be present in any part of the body. The current treatments include conservative noninvasive measures such as aspirin, limb elevation and compression bandage. Invasive therapies include sclerotherapy and laser therapy. The best alternative to eradicate abnormal tissue is surgery,² which aims to locate the nest and close arteriovenous shunts using isolated techniques or in combination with embolisation, resection or amputation.³ These procedures can be a challenge for the surgeon due to possible anatomical alterations with the imminent risk of bleeding.

We report limb salvage by microsurgery for a girl with an arteriovenous malformation. She was initially a candidate for limb amputation. All procedures were in accordance with the ethical standards of the responsible committee on human experimentation at Rehabilitation Hospital, Luis Guillermo Ibarra Ibarra and with the Helsinki Declaration of 1975, as revised in 2008. This work was evaluated and approved by the research and ethics committees of the Rehabilitation Hospital. Informed consent was obtained from the patient.

Case history

A 16-year-old girl was diagnosed with an arteriovenous malformation involving the brachial, ulnar, interosseous radial and palmar arch segments (Figure 1). Angiography was performed (Figure 2) prior to embolisation, but this procedure was cancelled after finding a compromised brachial segment. A subsequent consultation with plastic surgery was requested and the patient was scheduled for surgical repair with en-bloc resection of the arteriovenous malformation of all segments with extended brachial approach. The fourth and fifth fingers were resected en bloc (Figure 3). After corroborating elimination of turbulence, a lateral anterolateral thigh flap was performed for the lateral reconstruction of the hand. The patient has made satisfactory clinical progress (Figure 4), with remission of turbulence, and with adequate skin coverage.

Figure 1 .

Cutaneous component of the arteriovenous malformation of the palmar arch, flexion contracture of the fourth and fifth fingers. Bleeding stigma observed.

Figure 2 .

(a) Volumetric reconstruction of computed tomography with contrast in the coronal plane, showing a dilated path of the distal third of the ulnar artery with a vascular nest in the thenar and hypothenar region. (b) Angiogram with digital subtraction showing dilated efferent ulnar artery with plexiform vascular nest in the soft tissues of the thenar and hypothenar region, with apparent involvement of the deep and superficial arterial arch. Early enhancement of venous return is observed through the cephalic vein.

Figure 3 .

(a) Ligation of all arteriovenous malformation communication segments, arm section. (b) Anterolateral thigh flap including a 7cm vascular package. (c) Reconstruction can be seen, together with block resection of the forearm malformation. (d) Final result.

Figure 4 .

Evaluation at three-month follow-up. (a) Gross hand function. (b) Fine hand function.

The main symptoms experienced by the patient were pain and recurring bleeding in the right hand. Pain was controlled by nonsteroidal anti-inflammatory drugs. During the initial evaluation, the patient was not short of breath and had no systemic symptoms that would suggest high-output cardiac failure.

Embolisation is recommended prior to the surgical procedure; however, because of the associated inflammatory reaction, which generates greater surgical complexity, the decision was made to perform a procedure that would decrease tissue damage, minimise pain and preserve hand function while maintaining favourable aesthetic results.

The blood flow was controlled using a pneumatic bracelet, with minimal blood loss (280cc) and no need for transfusion. Truncal vascular flow was controlled by looping the brachial artery with vascular silicon bands. Haemostasis was achieved using a bipolar cautery. Uncontrolled bleeding might require proximal extremity tourniquet for life threatening haemorrhage. Massive transfusion protocol can be activated. Pain control was achieved using ketorolac 10mg and acetaminophen 500mg intravenously eight-hourly for five days, and tramadol 100mg intravenously eight-hourly for two days. Wound care was done using nonadherent petrolate impregnated gauze for a seven-day period. The patient received 10 physical rehabilitation sessions and 10 occupational therapy sessions. There was no need for psychotherapy.

Preoperatively, the affected hand presented with fourth and fifth finger flexion contracture. Intrinsic lesions (arteriovenous malformations, anomalous muscle insertions and tumours) lead to chronic flexion contracture and usually end in digital ablation due to the complete functional disability, including writing. Chronic pain is also a very common symptom.

Discussion

Vascular malformations are complex congenital anomalies of blood vessels that can lead to stroke, life-threatening bleeds, disfigurement, overgrowth and/or pain. Therapeutic options are limited and a multidisciplinary approach is preferred, especially for arteriovenous malformations. Multiple mosaic-activating variants have recently been reported in four genes of the RAS/MAPK pathway: KRAS, NRAS, BRAF and MAP2K1. This pathway is commonly activated in cancer and it is responsible for the germline related RASopathies. These variants were more frequently found in high-flow than in low-flow arteriovenous malformations, thus opening a new line of personalised treatment with the potential use of existing targeted cancer therapies.⁴

With the recent development of multiple reconstructive surgery techniques, especially microsurgery and tissue transfer, it is possible to expand the therapeutic options, achieving more refined, aesthetic and safe procedures that allow complex reconstructive problems to be resolved.^5,6 When there is involvement of muscular, cutaneous or nervous structures, it is usually best to perform en-bloc resection with subsequent reconstruction.

Conclusion

There is no contraindication for resection of arteriovenous malformation with microsurgical reconstruction. Tissue transfer is one available option for stability and wound coverage for the treatment of secondary sequelae after a resection of an arteriovenous malformation. Successful results may support further use of this technique in a larger group analysis.