Transient neurologic symptoms (TNS) following spinal anaesthesia with lidocaine versus other local anaesthetics.
BACKGROUND
Spinal anaesthesia 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 anaesthesia. Follow up of patients who received uncomplicated spinal anaesthesia 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' (TNS).


OBJECTIVE
To study the frequency of TNS and neurologic complications after spinal anaesthesia with lidocaine compared to other local anaesthetics.


METHODS
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 handsearched the reference lists of trials and review articles.


METHODS
We included all randomized and quasi-randomized studies comparing the frequency of TNS and neurologic complications after spinal anaesthesia with lidocaine as compared to other local anaesthetics.


METHODS
Two authors independently evaluated the quality of the relevant studies and extracted the data from the included studies.


RESULTS
Sixteen trials reporting on 1467 patients, 125 of whom developed TNS, were included in the analysis. The use of lidocaine for spinal anaesthesia increased the risk of developing TNS. 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 (RR) for developing TNS after spinal anaesthesia with lidocaine as compared to other local anaesthetics (bupivacaine, prilocaine, procaine, levobupivacaine, ropivacaine, and 2-chloroprocaine) was 7.31 (95% confidence interval (CI) 4.16 to 12.86). Mepivacaine was found to give similar results as lidocaine and was therefor omitted from the overall comparison to diminish the heterogeneity.


CONCLUSIONS
The risk of developing TNS after spinal anaesthesia 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 TNS, consideration should be given to choosing a neutral descriptive term which does not imply a particular causation. One study about the impact of TNS 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 anaesthesia.
Zaric
Dusanka
D
Department of Anaesthesiology, University of Copenhagen, Frederiksberg Hospital, Denmark, Nordre Fasanvej 57, Frederiksberg, Denmark, 2000. Dusanka.Zaric@frh.regionh.dk
Pace
Nathan Leon
NL
D000775:Anesthesia, Spinal / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000009:adverse effects*; D006801:Humans; D007866:Leg / Q000294:innervation*; D008012:Lidocaine / Q000009:adverse effects*; D010146:Pain / Q000139:chemically induced*; D010523:Peripheral Nervous System Diseases / Q000139:chemically induced*; D016032:Randomized Controlled Trials as Topic
D000779:Anesthetics, Local; D008012:Lidocaine