Spinal anesthesia has been in use since 1898. During the last decade, there has been an increase in the number of reports implicating lidocaine as a possible cause of temporary and permanent neurologic complications after spinal anesthesia. Follow-up of patients who received uncomplicated spinal anesthesia revealed that some of them developed pain in the lower extremities after an initial full recovery. This painful condition that occurs in the immediate postoperative period was named “transient neurologic symptoms” (TNSs).
To study the frequency of TNSs and neurologic complications after spinal anesthesia with lidocaine compared with other local anesthetics.
We searched the Cochrane Central Register of Controlled Trials Register (CENTRAL) (The Cochrane Library, Issue 4, 2008); MEDLINE (1966 to August 2008); EMBASE (1980 to week 35, 2008); LILACS (August 2008); and hand-searched the reference lists of trials and review articles.
We included all randomized and quasi-randomized studies comparing the frequency of TNSs and neurologic complications after spinal anesthesia with lidocaine compared with other local anesthetics.
DATA COLLECTION AND ANALYSIS:
Two authors independently evaluated the quality of the relevant studies and extracted the data from the included studies.
Sixteen trials reporting on 1467 patients, 125 of whom developed TNSs, were included in the analysis. The use of lidocaine for spinal anesthesia increased the risk of developing TNSs. There was no evidence that this painful condition was associated with any neurologic pathology; the symptoms disappeared spontaneously by the fifth postoperative day. The relative risk for developing TNSs after spinal anesthesia with lidocaine compared with other local anesthetics (bupivacaine, prilocaine, procaine, levobupivacaine, ropivacaine, and 2-chloroprocaine) was 7.31 (95% confidence interval: 4.16–12.86). Mepivacaine was found to give similar results as lidocaine and was therefore omitted from the overall comparison to diminish the heterogeneity.
The risk of developing TNSs after spinal anesthesia with lidocaine was significantly higher than when bupivacaine, prilocaine, or procaine were used. The term “transient neurological symptoms” implies neurologic pathology. Failing identification of the pathogenesis of TNSs, consideration should be given to choosing a neutral descriptive term, which does not imply a particular causation. One study about the impact of TNSs on patient satisfaction and functional impairment demonstrated that non-TNS patients were more satisfied and had less functional impairment after surgery than TNS patients, but this did not influence their willingness to recommend spinal anesthesia.
Zaric D, Pace NL. Transient neurologic symptoms (TNS) following spinal anaesthesia with lidocaine versus other local anaesthetics. Cochrane Database Syst Rev 2005, Issue 4. Art. No.: CD003006. DOI: 10.1002/14651858.CD003006.pub2.