Polymelia of the upper limb

Abstract

BACKGROUND: The most rare and extremely rare malformation of the upper limb is polymelia, i.e., doubling (triple) limb. In the literature, no more than 20 cases of an increase in the number of lower limbs and only three cases of doubling (triple) of the upper limb (in humans) have been described. CLINICAL CASE: A 2-year-old child diagnosed with polymelia of the right upper limb was examined and treated at our clinic. Clinical examination revealed two shoulder blades and one clavicle, with a normal anatomical location and development. Behind, an upper limb ended with the stump of the forearm, represented by an underdeveloped ulna. Moreover, the elbow joint was in a state of flexion contracture at an angle of 170, and the ulna was turned posteriorly and 1520 medially. The anterior humerus in the proximal section was underdeveloped, and in the distal section, it articulated in a normally formed elbow joint with the radius and ulna. The hand had five fingers with moderate underdevelopment and deformity of the 5th finger. After examining the bone, muscle, and vascular anatomy of the doubled limb, surgery was performed; as a result, a nearly complete anatomical and functional limb was reconstructed from the two segments of one upper limb. DISCUSSION: Polymelia is an extremely rare variant of a congenital anomaly of the limbs; thus, only a few cases are reported in the literature, which differs significantly from each other in clinical manifestations. Many questions related to the etiology and pathogenesis of these malformations are unexplored. The doubling of the limbs in animals is caused by both teratogenic environmental factors and genetic mutations. In any case, reconstructive surgery makes it possible to effectively treat children with such anomalies in the development of the limbs and obtain good results. CONCLUSIONS: The restoration of the upper limb of children with polymelia is quite difficult, but doable. Adequate analysis of all examination data and rational planning of surgical intervention in such cases creates conditions that enable achieving the maximum anatomical and functional results of upper limb reconstruction in children with this developmental anomaly.