TRANSIENT NEUROLOGIC SYMPTOMS AFTER SPINAL-ANESTHESIA WITH MEPIVACAINE AND LIDOCAINE

Background: Spinal anesthesia with lidocaine is ideal for ambulatory s urgery because of its short duration of action. However, transient neu rologic symptoms (TNS) occur in 0-40% of patients, The incidence of TN S with mepivacaine, which has a similar duration of action, is unknown . Methods: Sixty ambulatory patients undergoing knee arthroscopy recei ved spinal anesthesia in a randomized, double-blinded manner, with eit her 45 mg 1.5% mepivacaine or 60 mg 2% lidocaine. An L3-L4 midline app roach was used with a 27-gauge Whitacre needle and a 20-gauge introduc er. The local anesthetic was injected over approximately 30 s with the aperture of the Whitacre needle in a cephalad direction. Two to 4 day s after operation, each patient was questioned about the development o f TNS. In addition, the two groups were compared for time to regressio n of sensory and motor blockade and time to discharge milestones. Resu lts: Three patients receiving lidocaine were lost to follow-up. None o f the 30 patients in the mepivacaine group developed TNS, whereas 6 of 27 (22%) in the lidocaine group did (P = 0.008). Time to regression t o the L5 sensory level and to complete resolution of motor block were similar in both groups. The times to discharge milestones were also co mparable, Conclusions: The incidence of TNS is greater with 2% lidocai ne than with 1.5% mepivacaine for patients having unilateral knee arth roscopy under spinal anesthesia. Mepivacaine seems to be a promising a lternative to lidocaine for outpatient surgical procedures because of its similar duration of action. Further studies are warranted to deter mine the optimal dose of intrathecal mepivacaine for ambulatory surger y and the incidence of TNS with other doses and concentrations of intr athecal mepivacaine.