Treatment of pain by vagal afferent stimulation

Abstract

Method and apparatus for treating severe chronic, persistent or recurring neuropathic or psychogenic pain, or pain which is nociceptive if the patient is suffering from terminal disease, by selectively applying a pulse waveform to a lead/electrode implanted on the patient's cervical vagus nerve or other site preferably above the location of the pain to stimulate afferent fibers for activating a descending anti-nociceptive pathway and thereby blocking incoming pain signals. The pulse waveform has programmable pulse width, current level and frequency, and pulse sequence on and off time durations. The programmed pulse sequences are applied to the implanted electrode either on a continuous basis, or only during the period the patient is normally awake, or is initiated by the patient or automatically in response to the onset of pain. A method for use in advancing relief and control of pain includes providing the lead/electrode assembly to be implanted and the generator for the programmable pulse sequences, incorporating a connector on the generator to accommodate the lead, restricting the ranges of programmable values of the pulse sequences to values which in combination will stimulate the small afferent fibers of the vagus nerve to activate a descending anti-nociceptive pathway, and adapting the generator for physician selection of manner of control of commencement and cessation of the pulse sequences.