The electrical impulses are generated by a small device called a neurostimulator – similar to an artificial cardiac pacemaker – which is implanted in the buttock, chest, low abdomen, beneath the shoulder blade or below the clavicle.
Weiner showed that placing a PNS electrode close to a nerve is effective for pain relief and a technically simple procedure.
Subsequently, prospective randomized controlled trials were launched to gather additional clinical evidence.
"[4] In September 2011, St Jude Medical Inc. became the first company to receive European approval for the use of PNS in treating chronic migraine.
[1] Risks that may be highlighted include no guarantee of effectiveness, infection, nerve damage, painful direct muscle stimulation, lead movement with loss of stimulation, lead fracture, battery failure, eventual need for battery replacement, hematoma and seroma formation.
[1] In most cases, a trial (test) lead placement is performed in order to assess whether the stimulation will work as expected.
[8][9] Electrical impulses are sent through the lead and its position is adjusted until the patient reports a "pins-and-needles" sensation, called paresthesia, across the areas of the nerves.
[8][10] The lead(s) are then tunneled to a neurostimulator device which is usually implanted the buttock, chest, low abdomen, beneath the shoulder blade or below the clavicle.
In addition the study showed that, on average, the treatment group (device on) had 6.1 fewer days of headache days per month which was more than double the average reduction for the control group (device off), which is statistically significant (p<0.001).
The clinical study investigators reported that the overall rate of serious device and procedure related adverse events was 1% and that these included one infection and one case of post-operative pain which required additional hospitalization.
In February 2011, the ONSTIM clinical study investigators reported three-month results from a randomized controlled trial of patients with chronic migraine.
In December 2009, the PRISM study investigators reported three-month results in abstract form from a randomized controlled trial of 125 patients with chronic migraine.