These are one of the latest inventions in the field of pain medicine that are useful in the most painful and difficult to treat conditions. Principally they are programmable computer hardware devices that are implanted inside the body in a skin pocket and are connected with the spinal cord through very fine electrodes. SCS does not deliver any drug in the body but instead deliver electrical signal at pre decided level and alter the pain perception. SCS are based on the gate control theory of the noble prize winning scientists Wall & Melzack. As per this theory, upon stimulation of certain receptors in the pain transmitting system closes the gate and thus preventing further entry of pain producing signals. These devices are programmed with regards to frequency, pulse width and wavelength to modify the pain perception pathway and are adjusted according to the individual response.
Their implantation needs minimal surgical intervention that can be done even under local anesthesia and mild sedation. Except for the lowest incidence of minor complications related to the surgical procedure, like bleeding and infection etc, these procedures are extremly safe for the patient and do not require prolonged hospitalization. Initially, only the lead electrodes are implanted percutaneously which are connected to an external unit that controls the parameters. This temporary arrangement is tested on the patient for a few days or weeks during which time the patients response is tested. If the patient is convinced of the positive outcome, the external unit is replaced with an internally placed unit that is connected to the lead electrodes after tunneling the leads just below the skin. The internally placed SCS system is finally programmed as per the patients needs and he is taught how to alter the settings. The newer SCS units have a long battery life ranging from approximately 8 to 10 years. The latest SCS units now come with rechargeable batteries and can have a very long life and are thus highly cost effective.