TENS
Alternative Treatments for Facial Neuralgias

Disclaimer.

 TENS means transcutaneous electrical nerve stimulation of the skin. In simple terms, a (very weak) electric current is used to block the pain signals. There is some scientific evidence that this treatment could at least in theory have a physiological basis (according to the gate-control theory of pain, the electrical signal may block or mask the pain signal before it can be perceived as pain). The current is run through small tape-on electrodes, which can be attached either to the area of the affected nerve or, occasionally, to unaffected nerves whose pathways are related to the affected nerve. (In the case of TN pain in a single nerve branch, this may mean that the electrodes are attached either to a nerve branch that is not painful, or to the nerve branch on the opposite side of the face).

TENS is tried almost routinely for certain types of pain, such as post-herpetic neuralgia and, for example, pain following an amputation. However, it is very difficult to verify the treatment, as a double-blind experiment cannot really be made. Therefore, TENS must be considered a treatment that has anecdotal evidence behind it, but is still somewhat controversial.

For TN, the evidence is especially anecdotal. As a personal observation (with very limited value), I would say that the track record for classical TN does not seem to be very good. For atypical forms, there may be better success. The best results seem to be for postherpetic trigeminal neuralgia, for which there are few other effective treatments. As with many alternative treatments, the results tend to be extremely personal; some people report that their pain increased, others report considerable pain relief.
 

TENS and Nerve Stimulation 
The Interstitial Cystitis Network briefly describes TENS and its use.

TENS   
This study suggests that TENS treatment success might be due to placebo effect.