Background and Objectives. Unintentional subdural block, while attempting an epidural anesthetic, is a rare but known complication. The authors describe a radiologically confirmed case of an unintentional combined epidural and subdural block while attempting to perform an epidural block for transurethral resection of prostate in a middle-aged man.

Methods. Loss of resistance to air injection was used for identifying the epidural space prior to catheter placement. Following the epidural injection of 20 mL of a 1.5% lidocaine and 0.5% bupivacaine mixture, the patient developed rapid, intense, prolonged, and extensive bilateral motor block up to C2 level.

Results. The patient had aphonia and respiratory paralysis requiring endotracheal intubation and controlled ventilation for 3 hours.

Conclusions. Postoperative radiologic examination revealed the spread of the dye in both epidural and subdural spaces, causing the extensive sensory and motor block.