Compression of the Ulnar Nerve in the Ulnar Tunnel Caused by an Anomalous Pulsatile S-shaped Ulnar Artery

ABSTRACT

PURPOSE: Compression of the ulnar nerve in the ulnar tunnel is a relatively uncommon condition. Many authors have described several etiologies of ulnar nerve compression. We experienced two cases of ulnar nerve compression in the ulnar tunnel due to an anomalous pulsatile S-shaped ulnar artery. METHODS: Case 1: A 51-year-old man was referred with numbness and paroxysmal tingling sensation along the volar side of the ring and little fingers of his right hand for 6 months. When exploration, the ulnar artery was pulsatile S-shaped and was impinging on the ulnar nerve. To decompress the ulnar nerve, the tortuous ulnar artery was mobilized and translocated radially onto the adjacent fibrous tissue. Case 2: A 41-year-old man was referred with tingling sensation on the 4th, 5th finger of the right hand for 4 months. Sensory nerve conduction velocities of the ulnar nerve was delayed. Preoperative 3D angio CT scan showed an anomalous S-shaped ulnar artery. Same operation was done. RESULTS: The postoperative course was uneventful. After decompression, paroxysmal tingling sensation decreased to less than 1 minute per episode, occurring 1 or 2 times a day. After 4 months, they had no more episodes of numbness and tingling sensation. Examination demonstrated good sensation to pinprick and touch on the ulnar aspect of the hand. CONCLUSION: We report two cases of ulnar nerve compressive neuropathy that was caused by an anomalous pulsatile S-shaped ulnar artery in the ulnar tunnel. Although this is an unusual cause of ulnar nerve compression, the symptoms will not spontaneously resolve. The prompt relief of compressive neuropathic symptoms following the translocation of the impinging ulnar artery from the affected ulnar nerve onto adjacent tissue proved that the ulnar nerve compression is due to the anomalous vessel.