Presentations

Abstract

Introduction:

Aneurysms and pseudoaneurysms of the ulnar artery are a rare clinical occurrence that are often misdiagnosed in adult and pediatric patients. This vascular phenomenon is caused by an intimal tear leading to hemorrhage into the surrounding tissue. Ulnar artery aneurysms and pseudoaneurysms in adults are better described in comparison to pediatric cases. Ulnar pseudoaneurysms have varying etiologies in pediatric patients. Several causes have been observed such as arterial infection, connective tissue diseases and trauma. Here, we present the case of an ulnar pseudoaneurysm of the right upper extremity in a 4-year-old male with a recent history of trauma. Case Information A 4-year-old right hand dominant male with past medical history of sacral melanocytic nevi presented to orthopaedic oncology clinic three weeks after a fall on his outstretched right hand. He complained of ecchymosis, pain, and progressive swelling in his right hand since his fall. Physical exam showed a volar cystic mass near the hypothenar eminence with overlying ecchymoses. The mass was pulsatile and tender to palpation. The presumptive diagnosis upon exam was a potential vascular injury, vascular anomaly, aneurysmal cyst, or an undiagnosed hand fracture. An Allen's test performed at the time of initial evaluation was within normal limits. An ultrasound was ordered to rule out the possibility of congenital vascular malformations such as a macrocystic arteriovenous malformation or additional soft tissue mass. Ultrasound revealed a 1.8 x 1.1 x 1.5 cm pseudoaneurysm with arteriovenous fistula and adjacent soft tissue swelling. CT angiogram was then ordered and showed radial dominant flow as well as a 2.0 x 1.1 cm pseudoaneurysm arising from the palmar surface of the ulnar artery at the level of the hamate, which was confirmed on direct visualization. Subsequently, the pseudoaneurysm was resected and end to end anastomosis of the proximal and distal ends of the ulnar artery was completed using a lateral circumflex femoral artery graft. The patient's surgical site was checked and to confirm graft patency; an Allen's test was performed both clinically and with doppler ultrasound, capillary refill of each digit was examined, and a doppler of the ulnar and radial arteries and the superficial palmar arch was normal. At 2- week follow-up post-surgery the patient had asymptomatic function of his right hand.

Discussion:

Ulnar pseudoaneurysms have varying etiologies in pediatric patients. Several causes have been observed such as arterial infection, connective tissue diseases and trauma. Few instances of ulnar pseudoaneurysms are reported in the literature with one systematic review reporting 34 cases, 35% of which being pediatric. Of these pediatric cases, 17% were initially misdiagnosed. Misdiagnosis of upper extremity aneurysms and pseudoaneurysms are a serious cause for concern because without adequate treatment these can lead to serious complications such as thrombosis, skin necrosis, uncontrolled bleeding, and growth restrictions. If collateral flow is established, the pseudoaneurysm is typically resected and the vessel is repaired using end to end anastomosis. In this case, we opted to reconstruct the ulnar artery using a lateral circumflex femoral artery graft despite collateral flow through the radial artery being established. This is because we believe arterial reconstruction in pediatric patients can be beneficial for several reasons. Ulnar artery ligation in pediatric patients imparts an increased risk of growth restriction. Also, with ligation of the ulnar artery the patient incurs the risk of devascularization with an injury to the ipsilateral radial artery later in life. Additionally, since all pediatric patients would undergo ulnar artery repair there would no longer be a need for transfemoral angiography, preoperative plethysmography, or intraoperative plethysmography. Preoperative ultrasound with doppler flow is all that is required prior to surgery which is a more efficient, reliable, and cost-effective method of diagnosis. Finally, donor site morbidity in the thigh is very low and should not be considered as a potential hindrance for arterial reconstruction.

Conclusion:

Here, we present a case of a pediatric patient with a traumatic pseudoaneurysm of the upper extremity, which was initially presumed to be a hand fracture versus a potential vascular anomaly. This case highlights the importance of prompt diagnosis and treatment of upper extremity pseudoaneurysms in patients to avoid potentially devastating complications. In addition, we propose the reconstruction of all pediatric ulnar arteries following pseudoaneurysm resection to increase cost efficiency and reduce future possible complications.