This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lambert, D. H. Search for Related Content PubMed PubMed Citation Articles by Lambert, D. H.

---

LETTER TO THE EDITOR

Is TNS Really No Big Deal?

Department of Anesthesiology, Boston Medical Center, Boston, MA, donlam{at}fastmail.us

To the Editor:

Zaric et al. state that the incidence of lidocaine transient neurological syndrome (TNS) is not dose dependent (1). In the cited studies (2,3), the dose was the same. Only the concentration of lidocaine differed.

More importantly, the authors present a one sided TNS story: "TNS shows no evidence for localized nerve damage." The implication is that TNS is no big deal.

They ignore the possibility that TNS is nerve injury that eventually ceases to cause pain. I make the analogy to angina and myocardial infarction. I propose that TNS pain is associated with nerve inflammation that either resolves (similar to angina) or that continues to cell death (similar to myocardial infarction) and eventual pain resolution. It is beyond the scope of this letter to develop this important concept, but there is circumstantial evidence to support it.

Intrathecal lidocaine causes inflammation of the cauda equina nerves (4-6). This inflammation could totally resolve (similar to angina) or the nerves could go on to scar or apoptosis (5,7-9) (similar to myocardial infarction).

Although there is not definitive proof for TNS-associated nerve injury, it is not impossible. No anesthesiologist would employ an anesthetic that causes angina or myocardial infarction. Are we flirting with something similar by causing TNS?

References

1. Zaric D, Christiansen C, Pace NL, Punjasawadwong Y. Transient neurologic symptoms after spinal anesthesia with lidocaine versus other local anesthetics: a systematic review of randomized, controlled trials. Anesth Analg 2005;100:1811-6.[Abstract/Free Full Text]
2. Hampl KF, Schneider MC, Pargger H, et al. A similar incidence of transient neurologic symptoms after spinal anesthesia with 2% and 5% lidocaine. Anesth Analg 1996;83:1051-4.[Abstract]
3. Pollock JE, Liu SS, Neal JM, Stephenson CA. Dilution of spinal lidocaine does not alter the incidence of transient neurologic symptoms. Anesthesiology 1999;90:445-50.[Web of Science][Medline]
4. Aldrete JA. Reader questions safety of spinal anesthesia. Anesthesia Patient Safety Foundation Newsletter 2003;18:60.
5. Aldrete JA. Nerve root "irritation" or inflammation diagnosed by magnetic resonance imaging. Anesthesiology 2003;98:1294.[Medline]
6. Avidan A, Gomori M, Davidson E. Nerve root inflammation demonstrated by magnetic resonance imaging in a patient with transient neurologic symptoms after intrathecal injection of lidocaine. Anesthesiology 2002;97:257-8.[Web of Science][Medline]
7. Johnson ME. Potential neurotoxicity of spinal anesthesia with lidocaine. Mayo Clin Proc 2000;75:921-32.[Abstract]
8. Johnson ME. Research update: in vitro assessment of local anesthetic neurotoxicity. ASRA Newsletter, 2002:1-3.
9. Johnson ME, Uhl CB, Spittler KH, et al. Mitochondrial injury and caspase activation by the local anesthetic lidocaine. Anesthesiology 2004;101:1184-94.[Web of Science][Medline]

This article has been cited by other articles:

				V. Umbrain, L. Shi, M.-H. Lauwers, I. Smolders, Y. Michotte, and F. Camu Intrathecal lidocaine elevates prostaglandin E2 levels in cerebrospinal fluid: a microdialysis study in freely moving rats Br. J. Anaesth., November 1, 2008; 101(5): 716 - 722. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lambert, D. H. Search for Related Content PubMed PubMed Citation Articles by Lambert, D. H.