The International Neuromodulation Society defines Neuromodulation as “the change in neuronal activity through electrical stimulation or chemicals delivery to targeted sites of the body.” This is done to normalize – or modulate – nerve function.
Neuromodulation is an emerging technique which started after it became possible to store and to control electricity in the mid eighteenth century.
Its historical basis emanates from Melzack and Wall’s gate control theory of pain proposed in 1965. Initially destructive surgical procedures like cutting the nerves were used but as it came to our knowledge that damage to nervous tissue can itself cause chronic pain, such procedures were replaced with reversible, modulatory treatments like Neuromodulation. Neuromodulation therapy – a therapy which exerts its effects by targeting dysfunctional neural circuitry – stands poised to dramatically influence the help for addiction to drugs. As our understanding of addictive behavior and its associated neural underpinnings has evolved, new neuronal targets for therapy have emerged.
Nervous system pathways in chronic pain can be modulated through a range of electromagnetic or chemical stimuli such as:
Strong magnetic field (Repetitive Trans-cranial Magnetic Stimulation)
Very small electric current (Electrical Stimulation)
Drug instilled directly in the subdural space (Intrathecal Drug Delivery)
The applications of therapeutic electrical stimulation are very diverse and new applications are being developed. Spinal cord stimulation has shown to have varying degrees of efficacy to address a variety of drug resistant neuropathic and nociceptive pain syndromes such as:
Post-laminectomy syndrome
Low back pain
Complex regional pain syndrome
Peripheral neuropathy
Peripheral vascular disease
Spinal cord stimulation is commonly used since 1980 in which mild electrical pulses are given to the spinal cord that acts as a reversible, non-pharmacological therapy for chronic pain management. The patients who experience significant pain reduction during a temporary trial, a permanent implant may be offered. In permanent implant thin microelectrodes are inserted to the spinal area to be addressed which is connected to a pulse generator through a connecting wire under the skin. Pulse generator is similar to the cardiac pacemaker and is buried under the skin in the abdomen.
In 1977 it was first suggested that if morphine (Opioid analgesic) is given into the spinal fluid its effectiveness might be better than if it is given into the blood due to the presence of blood brain barrier. Since the implantation of first morphine infusion pump in 1981, this route is increasingly used world over for intractable pain of cancer as well as non-cancer origin in patients with good life expectancy. As drug doesn’t need to overcome blood brain barrier, only a small dose is sufficient to achieve desired effects with fewer side effects. .
Baclofen is another drug used to treat spasticity since 1984 via intrathecal route. When given directly to the spinal fluid its concentration is 400 times higher with the same dose when given through blood which is highly effective in relieving the symptoms. Intrathecal baclofen has proved to be extremely effective in controlling spasticity due to spinal cord injury and diseases such as multiple sclerosis and can also be effective in spasticity of cerebral origin i.e. after brain injury, stroke, hypoxia etc.
Both intrathecal drug delivery systems as well as spinal stimulation devices are becoming smaller in size and more user friendly day by day. Similarly both the techniques are being used in steadily increasing numbers.
Neuromodulation can bring considerable relief and improvement; often after all other measures have failed. Its earlier implementation may even modify the course of some conditions; it should not be regarded as a treatment of last resort.
At ANFN center we offer both spinal cord stimulation as well as implantation of intrathecal drug delivery systems to carefully selected patients whose chronic conditions cause significant suffering and disability. We use US made stimulation implants and infusion pumps in the drug delivery system. All the procedures are done according to the international standards maintained by International Neuromodulation Society guidelines.