EMS Physio

Combination therapy

In general terms, combination therapy involves the simultaneous application of ultrasound with an electrical stimulation therapy. In Europe diadynamic currents are frequently used but, in the UK, ultrasound is most often combined with two-pole interferential therapy. By combining ultrasound with an electrotherapy the advantages and effects of each treatment modality can be realised, but lower intensities are needed to achieve the same effect. Also, the accommodation effects that normally accompany electrotherapy are reduced (or even eliminated).

The main advantages of such a combination are said to be -

• In localising lesions (especially chronic) ie. diagnostic use.
• In ensuring accurate localisation of ultrasound treatment to
  provide increased accuracy/effectiveness in treating deeper
  lesions.
• In treating trigger points.

Possible Explanations

It would appear that by applying ultrasound to peripheral nerves their threshold of stimulation is reduced, thus making them more sensitive or excitable. It is likely that this effect is brought about by the alteration of the ion pump activity, predominantly Na+ and K+, but also Ca++. By altering the transport of these ions across the cell membrane the resting potential will be altered and, in this case, it would seem that it results in a reduced threshold for depolarisation.

It is reasonable to expect that this effect occurs in other tissue (apart from nerve) although no direct evidence has been noted to date.

When electrotherapy is applied simultaneously with ultrasound through the same tissues a reduced intensity is required in order to achieve the same physiological/therapeutic effects when compared with electrotherapy in isolation. This can easily be demonstrated by turning off the ultrasound component whilst continuing with the electrotherapy. The patient very soon becomes aware of a much reduced sensation/effect which can be restored by restarting the ultrasound.

In addition the simultaneous application of ultrasound with electrotherapy minimises the accommodation phenomenon normally associated with electrical stimulation of the peripheral nerves.

The combination of ultrasound with interferential therapy appears to give rise to less adverse treatment effects than are associated with the combination of ultrasound with diadynamic currents or other electrical stimulations. It has also been suggested that a greater effective treatment depth can be achieved with an ultrasound/interferential combination.

Unlike routine interferential therapy the intensity of the electrical stimulation in combination therapy may need to be REDUCED during treatment, probably due to the continued effect of the ultrasound on the nerve membrane threshold.

In summary, by combining the two treatment modalities none of the individual effects of the treatment are lost, but the benefit is that lower treatment intensities can be used to achieve the same results and there are additional benefits in terms of diagnosis and treatment times.

Precautions

The therapist must be aware of the following precautions and potential hazards.

• Simultaneous connection of a patient to high frequency surgical equipment may result in burns at the site of the stimulator electrodes and possible damage to the stimulator itself.
• Operation in close proximity (less than 1 metre) to shortwave or microwave therapy equipment may produce instability in the stimulator output.
• Consideration must be given to the current densities for any electrode used with the Combination 855 Unit. Current densities greater than 2 mA rms/cm2 are not recommended because of the risk of burning. All the standard EMS conductive rubber electrodes may be used up to the maximum output of the unit without exceeding this figure. When using other electrodes, the maximum safe output current should be assessed before use. First estimate the effective contact area of the electrode in square cm, and then apply the following formula:
• rms output current (mA) = Area of electrode (cm2) x 2
• The ratio of the rms to the peak current for the different operating modes is given in the technical specification section of this manual.
• The output indication on the LCD shows the peak output voltage or the peak output current in mA depending upon the selected mode of operation.
  When using direct current, extreme care must be taken to ensure the patient's safety from electrochemical burning. In particular, care must be taken to avoid uneven pressure on the electrodes causing high local current density. Electrodes must not be applied where there are cuts or abrasions.