Monday, 2 April 2012

Not So Fast!

Before you jump into electrical stimulation, you need to consider the risks and contraindications for its use, for both externally applied and implanted FES systems. Although there are no absolute contraindications for externally applied FES, patients with a cardiac pacemaker or an automatic implanted defibrillator should be approached with extreme caution (Vernon, 2003). Electrical simulation applied to areas anywhere on the body has been found to in some instances to potentially interfere with the sensing portion of the pacemaker. Relative contraindications for FES include pregnancy, electrical sensitivity, healing wounds and patients with congestive heart failure or at risk of cardiac arrhythmias.  

For implanted FES systems, absolute contraindications encompass presence of an implanted cardiac pacemaker, active or recurrent sepsis, or uncontrolled spasticity (Vernon, 2003). With implanted FES systems antibiotic prophylaxis needs to be taken by individuals when undergoing invasive procedures (Vernon, 2003). There are no contraindications for the previous held concern with FES implants and MRI, which is reflected on the FDA-approved labels.

Caution has been raised in the use of other treatment modalities, short wave diathermy, microwave diathermy or therapeutic ultrasound diathermy with implanted FES, as there is a risk of heating at the electrode-tissue interface that could produce damage to tissue or nerve. NeuroControl Corporation indicated that these types of modalities should not be performed over implants to protect components of body tissue as well as the device (Vernon, 2003).

A risk of FES has been raised where the damaged nerve (thought to have been lost) can retard during the healing process with excessive use of FES. The long duration, high intensity pulse parameters used for denervated muscle can interfere with nerve sprouting as the nerve tries to regenerate, preventing the nerve from returning to its pre-injured state (Low & Reed, 2000). This is a precaution that has limited evidence, but it is still a worthwhile consideration to be aware of when applying FES. Hence, physiotherapist, patient and other health professionals involved should adhere to the recommended doses (not hammer the muscle/nerve too much) and should monitor/reassess the damage nerve to ensure true denervation.

FES is an electrical stimulatory device, so the general contraindications and precautions when apply such a device should not be neglected. The table below presents a general and encompassing list for the use electrical stimulatory devices:

Abdomen and lower back of pregnant women
Infective area
Active rheumatoid disease
Metallic implants
Acupuncture points in pregnancy
Morbid obesity
Acute inflammatory reaction
Obtunded reflexes
Anticoagulant therapy
Open epiphyses
Open wounds
Cancerous lesions
Plastic implants
Cardiac region of thorax
Carotid sinus
Recent intake of analgesia
Cement for Arthroplasty
Recent radiotherapy
Deep Vein Thrombosis
Stellate ganglion
Demand type pacemakers
Sympathetic ganglia
Dermatological conditions
Thyroid gland
Excessive oedema
Tissues of the central nervous system
Tubercular joints
Haemorrhagic regions
Underlying lung
Immune suppressant drugs
Unreliable patient
Implanted stimulators
Upper cervical spine where history of epilepsy
Impoverished circulation
Vagus nerve
Impoverished perception of pain
Wet dressings or adhesive tape

Fatigue of muscles being stimulated
The physiotherapist must check each subject’s FES equipment to ensure it is in working order and correct placement of the electrodes
The physiotherapist should also test the patients sensation by blunt and sharp differentiation

Cakmak, A. (2004). Electrical stimulation of denervated muscles. Disability and Rehabilitation 26(7), 432 – 433.

Low, J., & Reed, A. (2000). Electrotherapy explained: principles and practice. Oxford: Butterworth-Heinemann.
Vernon, W. (2003). Spinal cord medicine; principles and practice. New York, Demos medical publishing.

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