The addition of lidocaine to bupivacaine does not shorten the duration of spinal anesthesia: a randomized, double-blinded study of patients undergoing knee arthroscopy.

Background: The duration of spinal anesthesia with bupivacaine is often too long for day surgery. A recent study of patients presenting for transurethral surgery suggested that the addition of a small amount of lidocaine to intrathecal hyperbaric bupivacaine could shorten the duration of the sensory and motor blocks. In this prospective, randomized double-blind study we investigated these findings in patients undergoing unilateral knee arthroscopy.