Trigeminal nerve injury associated with injection of local anesthetics: Needle lesion or neurotoxicity?

Background. The authors used comprehensive national registry and clinical data to conduct a study of adverse drug reactions (ADRs), in particular neurosensory disturbance (NSD), associated with local anesthetics used in dentistry. Methods. The study included data sets of annual sales of local anesthetics (from 1995 through 2007), 292 reports to the Danish Medicines Agency, Copenhagen, Denmark, of adverse reactions to local anesthetic drugs, and a clinical sample of 115 patients with NSD associated with local anesthetics.

The authors assessed lidocaine 2 percent, mepivacaine 2 percent and 3 percent, prilocaine 3 percent, and articaine 4 percent sold in cartridges. Results. The study results showed a highly significant overrepresentation of NSDs associated with articaine 4 percent, in particular with mandibular blocks.

Conclusions. The distribution of NSDs was disproportionate to the market share of three of the four drugs in both national registry data and clinical data. These findings indicate that the main cause of injury was neurotoxicity resulting from administration of the local anesthetic rather than the needle penetration.

Clinical Implications. Clinicians may consider avoiding use of high-concentration (4 percent) anesthetic formulations for blockanesthesia in the trigeminal area in cases in which there are viable alternatives.