Use of TENS to induce a nerve block

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Hi guys.

Has anybody heard of or had experience in using a TENS machine to induce an ankle block? I remember Craig Payne mentioning this back in the uni days. Reason I ask is I had a patient today who was booked in for VP needling for a long standing unresponsive stubborn VP on her R/sub 3rd MTPJ. I attempted a Tibial block but which was unsuccessful. She was however amenable to having the LA injected plantarly at the site. I warned her it would be very painful but she insisted. Yes it did hurt and yes she screamed, she was however a tough lady and the VP needling went ahead after the LA took effect.

Im curious if its possible to you use a TENS to induce a block causing sufficient anaesthesia to administer LA on the plantar surface of the foot without causing discomfort (and to ensure anaesthesia in case the TENS malfunctions and continuos screaming ensues)

Regards

Soss

 

Soss:

An easier solution is ethyl chloride spray which temporarily freezes the skin so that the needle puncture isn't painful. It takes only about a 5 second spray to freeze the skin so that a plantar injection can be given with much less pain. I use ethyl chloride spray for all my injections for plantar fasciitis (done directly on the plantar aspect of the heel), verrucae needling, nail avulsions/matrixectomies, sinus tarsi injections, neuroma injections, etc.

Here is the stuff I use (Gebauer's Ethyl Chloride® Medium Jet Stream Spray Bottle). I probably use it 2-5 times a day, every day of my practice.

 

There were people dabbling in this quite successfully in the 80's. I did try it, but it only worked sometimes.

 

I don't think it possible to establish a tibial anaesthetic block using TENS. I'd stand corrected if any colleague has managed it but the theory of the process is to bombard the skin with stimuli, such that it 'blocks' the pain gate (Melzack and Wall, The Challenge of Pain). Anecdotally, I've tried various 'nerve blocks' using this technique but all have failed. Try using the 'halfway between the inferior proximal tip of the calcaneus and the medial malleolus technique' to locate the posterior tibial pulse and then go slightly deep with your needle (dental self-aspirating syringe ideal). Failing this, try direct infiltration using the 'stab' technique and then inject very slowly. As mentioned by Kevin, ethyl chloride can be helpful but preparations such EMLA are ineffective on the plantar surface.

All the best

Bill

 

Thanks for the response everybody.