Objective:

To assess whether transcutaneous electrical nerve stimulation (TENS), applied during injection-based procedures, reduces procedural pain compared with prior injections without TENS in patients with headache disorders.

Background:

Procedural pain during peripheral nerve blocks and botulinum toxin injections can limit patient adherence to repeated treatments. Current strategies, such as topical anesthetics, provide limited relief. Non-invasive neuromodulation, including TENS, activates endogenous analgesic pathways and may reduce procedural discomfort. Prior work with remote electrical stimulation suggests potential benefit for injection pain, but TENS has not been evaluated in this context. 

Design/Methods:

Seven patients undergoing routine headache interventions (nerve blocks: n=4; botulinum toxin injections: n=3) received TENS using either HeadaTerm2 or TENS7000 devices applied to the upper arm immediately before and during injections. We used moderate, non-panful stimulation intensity. Patients reported prior procedural pain (without TENS) and current pain (with TENS) using a 0–10 Numerical Rating Scale (NRS) for average and maximum injection pain. 

Results:

Mean prior average pain was 6.5±0.76 and maximum pain was 7.3±0.76. With TENS, mean average pain decreased to 4.7±1.25 and maximum pain to 5.6±1.35, corresponding to reductions of 1.8 and 1.7 points, respectively. Six of seven patients rated the procedure as “less painful” than previous experiences; one reported “same pain.” No adverse effects occurred. 

Conclusions:

TENS applied during injection-based headache procedures was associated with reductions in procedural pain and high patient-reported tolerability. These preliminary findings support TENS as a non-pharmacologic adjunct to improve comfort and acceptance of repeated therapeutic injections. Controlled trials are warranted to confirm efficacy and optimize stimulation parameters.