Estim can be used to relieve pain for neurological or muscular pain, including acute, subacute, or chronic conditions, as a result of peripheral nerve injuries, trigger points, muscular strains, etc. 



Contraindications

Stimulation where active motion is contraindicated (jt fusion, sutured tendons, sutured nerves,  unfixated fracture); pacemaker or implanted stimulator; stimulation directly over superficial metal; active bleeding; malignancies; cognitive impairments or disorientation

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Precautions

Pregnancy, long-term steroid use, or over the carotid sinus



Estim provides pain relief through two mechanisms. The first is the gate theory, which occurs with high frequency TENS. Instant pain relief provided because large diameter fibers are stimulated, which travel to the brain faster than the smaller diameter delta c pain fibers (meaning only the tingling is perceived, not the pain). However, when the high rate TENS is withdrawn, so is the pain relief.  The second is opiate release, occurring with low rate and noxious level TENS.  The opiate pain theory suggests that the specific areas in the brain are stimulated from pain to release opiates, in efforts to inhibit pain. This takes around an hour or so to come into effect, but lasts for several hours after treatment.  

 

 

How to do it

High frequency TENS is used at 20 to 100 microseconds for the phase duration where no motor response is elicited and a frequency of 100-150 Hz.

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The current for high frequency TENS can be either asymmetric biphasic or interferential.

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• With interferential, use 4 electrodes, and place them so they will cross the treatment area. For interferential, the beat frequency is set at 4150 Hz with the beat high frequency at 150 Hz and the beat low frequency at 80 Hz with the carrier frequency is 4000 Hz.
• Asymmetric biphasic will utilize 2 electrodes and they can be placed either around the location or directly on the location.

The patient should feel a tolerable tingling sensation. Treatment time can be 24 hours a day, as the patient can take a portable unit home.

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Low frequency TENS is found at 100 to 600 microseconds for the phase duration and frequency of 2-10 Hz to the point of a tolerable muscle contraction. The current for low frequency TENS will either be Russian or biphasic with two electrodes placed around the treatment area. The treatment time is 20-30 minutes.

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Noxious level TENS parameters are on the Russian current setting, but the phase duration is 600-800 milliseconds, eliciting a painful yet tolerable response. Frequency is 50 bursts per second. Time is 12 seconds on and 8 seconds off. Treatment time is 10-15 minutes (or as long as the patient can tolerate).


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​Iontophoresis is a specialized estim unit used to increase the rate of healing for ulcers and burns through the use of electrical stimulation coupled with medication.



​​(Precaution: Make sure the patient is not allergic to the medication you are applying, and do not apply stimulation over damaged skin or open lesions)



For direct current electrical stimulation, iontophoresis is used to provide pain relief. Through the theory of "like-repels-like" and application of a positive or negative polarity, therapeutic ions are driven to the target to provide a particular response. When no topical medication is given, negative polarity attracts positive cells, such as white blood cells and macrophages for an immune response, and positive polarity attracts fibroblasts for collagen repair and remodeling. Iontophoresis should be used to treat a target of 8-10 mm deep



For iontophoresis, apply water or medicine to one electrode and place either around for periwound or on target tissue. The current can be direct current or high volt. Treatment time should be 20 min at 2 mA for a dose of 40 mA*min. Inspect the skin before and after each treatment and have the patient tell you if any change occurs during the treatment. Stop the treatment immediately if patient experiences irritation.



Various medications used with iontophoresis include:

Acetate- negative, used to treat calcium deposits

Dexamethasone- negative, used to treat tissue inflammation, such as plantar fasciitis

Hydrocortisone- positive, inhibits prostaglandins

Lidocaine- positive, decreases local pain by providing a nerve block