Guyon's Tunnel Syndrome during Pregnancy with Concomitant Anomalous Arch of the Ulnar Nerve: a Case Report

Numerous causes arereported for ulnar nerve compression at the wrist, known as Guyon''s tunnelsyndrome. In the present article, a patient with Guyon’s tunnel syndrome duringpregnancy concomitant with an anomaly of ulnar nerve is described. A 29-year-oldIranian woman presented with clinical features of Guyon''s tunnel syndrome (painand paresthesia in the fifth finger of the left hand and atrophy of the firstdorsal interosseus muscle). Symptoms of the patient appeared during the thirdtrimester of pregnancy. Electro diagnostic studies confirmed Guyon''s tunnelsyndrome. Surgical exploration revealed an anomalous arch of the ulnar nervepassing through the flexor carpi ulnaris (FCU) tendon. The anomalous arch ofthe ulnar nerve was released by resection of the segment of FCU tendon passingthrough the ulnar nerve arch. Therefore, in patients with Guyon''s tunnelsyndrome, the ulnar nerve anomaly should be kept in mind as a cause. Moreover,pregnancy may have a provocative effect on Guyon''s tunnel syndrome similar tocarpal tunnel syndrome (CTS).