High-concentration tetracaine for the management of trigeminal neuralgia: quantitative assessment of sensory function after peripheral nerve block.

OBJECTIVE

This study examined the effects of peripheral nerve block with high-concentration tetracaine for the management of trigeminal neuralgia, and evaluated sensory function by measuring the postblock current perception threshold.

METHODS

Five infraorbital nerve blocks were performed in five elderly patients using 4% tetracaine dissolved in saline or 0.5% bupivacaine. The authors used a neurometer to compare postblock current perception threshold between the block side and the contralateral healthy side, and used cold tests to assess the sensory level.

RESULTS

The analgesic effect of tetracaine blocks continued for a median period of 2 months (range, 1.5-months). Hypesthesia was observed in all patients after the block but resolved within a mean period of 2.2 weeks. Although differences in current perception threshold values between sides were not significant in any patient, block-side values in two patients were clinically higher than contralateral-side values (250 vs. 5 Hz) for some time before returning to normal levels.

CONCLUSION

Peripheral nerve block with high-concentration tetracaine is a relatively safe and useful technique in the management of trigeminal neuralgia, particularly among older patients and those with systemic problems.