Brachial plexus entrapment of interscalene nerve catheter after uncomplicated ultrasound-guided placement.

We report on the case of an entrapped interscalene nerve catheter in a 46-year-old male undergoing left shoulder arthroscopic lysis of adhesions for a frozen shoulder. The catheter was placed under ultrasound guidance without any apparent complications. The continuous interscalene nerve block was successfully used as the primary anesthetic and for postoperative pain management. Upon attempted catheter removal, the patient experienced severe pain and paresthesias. Fluoroscopy revealed possible brachial plexus involvement, and surgery was performed to extract the catheter, which had become hooked and entrapped around the C5 nerve root and sheath.