Occipital nerve stimulation (ONS), also called peripheral nerve stimulation (PNS) of the occipital nerves, is used to treat chronic migraine patients who have failed to respond to pharmaceutical treatments. The treatment involves the use of mild

electrical Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...

impulses to stimulate the

greater occipital nerve The greater occipital nerve is a nerve of the head. It is a spinal nerve, specifically the medial branch of the dorsal primary ramus of cervical spinal nerve 2. It arises from between the first and second cervical vertebrae, ascends, and then p ...

and

lesser occipital nerve The lesser occipital nerve or small occipital nerve is a cutaneous spinal nerve. It arises from second cervical (spinal) nerve (along with the greater occipital nerve). It innervates the scalp in the lateral area of the head posterior to the ...

which are part of the

peripheral nervous system The peripheral nervous system (PNS) is one of two components that make up the nervous system of bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside the brain ...

and are located at the back of the head just above the neck area. The electrical impulses are generated by a small device called a neurostimulator – similar to an

artificial cardiac pacemaker An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural cardiac pacemaker) or pacemaker is a medical device that generates electrical impulses delivered by electrodes to the chambers of the heart ei ...

– which is implanted in the

buttock The buttocks (singular: buttock) are two rounded portions of the exterior anatomy of most mammals, located on the posterior of the pelvic region. In humans, the buttocks are located between the lower back and the perineum. They are compose ...

chest The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...

, low

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...

, beneath the shoulder blade or below the

clavicle The clavicle, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the r ...

. The electricity is delivered to the

and

by small metal

electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials d ...

s which are arranged on thin leads and implanted just under the skin. The intensity of the electrical impulses can be adjusted using a small remote control device.

History

The history of PNS is thoroughly reported by Slavin, 2011. The use of PNS for chronic pain was first reported in 1967 by Wall and Sweet although the first implantations were performed in 1962 by Shelden. They demonstrated that electrical stimulation of peripheral nerves suppresses the perception of pain. A period of semi-experimental PNS usage continued for 15 – 20 years. During the latter half of the 1980s, PNS became an established surgical procedure. In the late 1990s, Weiner and Reed reported the

percutaneous {{More citations needed, date=January 2021 In surgery, a percutaneous procedurei.e. Granger et al., 2012 is any medical procedure or method where access to inner organs or other tissue is done via needle-puncture of the skin, rather than by using ...

technique of inserting electrodes in the vicinity of the occipital nerves to treat

occipital neuralgia Occipital neuralgia (ON) is a painful condition affecting the posterior head in the distributions of the greater occipital nerve (GON), lesser occipital nerve (LON), third occipital nerve (TON), or a combination of the three. It is paroxysmal, la ...

. Weiner showed that placing a PNS electrode close to a nerve is effective for pain relief and a technically simple procedure. This pioneering work heralded the start of the modern era of PNS. It was 2003 before Popeney and Aló proposed using PNS for the treatment of chronic migraine. Subsequently, prospective

randomized controlled trial A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical te ...

s were launched to gather additional clinical evidence. This is further detailed in an article published by Cephalagia titled "Safety and efficacy of peripheral nerve stimulation of the occipital nerves for the management of chronic migraine: Results from a randomized, multicenter, double-blinded, controlled study." In September 2011, St Jude Medical Inc. became the first company to receive European approval for the use of PNS in treating chronic migraine.

Candidates for the therapy

Appropriate candidates for PNS of the occipital nerves for the treatment of chronic migraine must be diagnosed with chronic migraine which is classified as intractable. Chronic migraine is defined by the International Headache Society (IHS) guidelines: * 15 or more migraine (without aura) headache days per month for more than 3 months with headaches lasting at least 4–72 hours in duration * At least 2 of the following: unilateral location, pulsating quality, moderate or severe pain intensity, aggravated by or causing avoidance of, routine physical activity (walking or climbing stairs) ** During the headache, at least one of the following:

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

and/or

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteri ...

photophobia Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of ...

and

phonophobia Phonophobia, also called ligyrophobia or sonophobia, is a fear of or aversion to loud sounds (for example fireworks)—a type of specific phobia. It is a very rare phobia which is often the symptom of hyperacusis. Sonophobia can refer to the hype ...

* Not attributed to another disorder * Absence of medication overuse Intractable chronic migraine is generally defined as chronic migraine with failure of three or more preventive drugs and at least moderate disability determined using a validated migraine disability instrument (e.g.

MIDAS Midas (; grc-gre, Μίδας) was the name of a king in Phrygia with whom several myths became associated, as well as two later members of the Phrygian royal house. The most famous King Midas is popularly remembered in Greek mythology for his ...

or HIT-6).

Procedure

Pre-operation

Prior to the implantation, patients usually undergo a psychological assessment to assess their well-being and mental health. The risks of the procedure will be discussed and the patient will be asked for their informed consent. Risks that may be highlighted include no guarantee of effectiveness,

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dis ...

, nerve damage, painful direct muscle stimulation, lead movement with loss of stimulation, lead fracture, battery failure, eventual need for battery replacement, hematoma and

seroma A seroma is a pocket of clear serous fluid (filtered blood plasma). They may sometimes develop in the body after surgery, particularly after breast surgery, abdominal surgery, and reconstructive surgery. They can be diagnosed by physical signs, ...

formation.

Implantation

In most cases, a trial (test) lead placement is performed in order to assess whether the stimulation will work as expected.

Local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general a ...

is applied to the back of the neck and a

Tuohy needle A Tuohy (/tOO-ee/) needle is a hollow hypodermic needle A hypodermic needle (from Greek ὑπο- (''hypo-'' = under), and δέρμα (''derma'' = skin)), one of a category of medical tools which enter the skin, called sharps, is a very ...

is advanced towards the location of the greater occipital nerve and lesser occipital nerve under fluoroscopic guidance. When the location is confirmed, a temporary lead is placed through the needle before the needle is carefully removed.

Electrical Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...

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. If paresthesia is successfully achieved in the right place, permanent leads are usually implanted at a later date. In some cases, the trial leads are left in for up to one week to see whether there is any relief of symptoms. Permanent lead placement may be carried out under

general anesthetic General anaesthetics (or anesthetics, see spelling differences) are often defined as compounds that induce a loss of consciousness in humans or loss of righting reflex in animals. Clinical definitions are also extended to include an induced coma ...

local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general a ...

with sedation. First, a small incision is made at the base of the skull, then a Tuohy needle is advanced under fluoroscopic guidance towards the location of the greater occipital nerve and lesser occipital nerve on one side of the head. When the lead is adequately positioned through the needle under fluoroscopic guidance, the needle is carefully removed and the lead is fixed in place. Since most patients require two leads, a second lead is usually inserted and fixed in place on the other side of the head in the same way. The lead(s) are then tunneled to a neurostimulator device which is usually implanted the

, low

, beneath the shoulder blade or below the

Clinical evidence

Results from three

s have been published. One randomized controlled trial of 157 patients with chronic migraine was published in October 2012. Participants were implanted with the device and then randomized to have the device turned on (the

treatment group In the design of experiments, hypotheses are applied to experimental units in a treatment group. In comparative experiments, members of a control group receive a standard treatment, a placebo, or no treatment at all. There may be more than one tr ...

) or off (the control group) for 12 weeks. After week 12, participants received active treatment until week 52. All participants had trial stimulation to ensure correct position of electrodes. A total of 153 participants completed 12 weeks in the trial. There was a statistically significant difference ( p<0.05) between the number of patients in the treatment group]and control group at the 30% reduction in pain level using the Visual analogue scale, Visual Analogue Scale (VAS). 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 event An adverse event (AE) is any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and which does not necessarily have a causal relationship with this treatment. An adverse event can ther ...

s was 1% and that these included one

and one case of post-operative pain which required additional

hospitalization A hospital is a health care institution providing patient treatment with specialized health science and auxiliary healthcare staff and medical equipment. The best-known type of hospital is the general hospital, which typically has an emergency ...

. In February 2011, the ONSTIM clinical study investigators reported three-month results from a randomized controlled trial of patients with chronic migraine. Participants were first given occipital nerve block. Those who responded were randomized into three groups. The first group was a treatment group (33 participants) and received adjustable stimulation. The other two groups were control groups and received sham stimulation for one minute per day or standard medical management (17 participants each). Patients who achieved a 50% or greater reduction in their number of headache days per month or a three-point or greater reduction in average overall pain intensity compared with baseline were defined as responders to the therapy. 39% of patients in the adjustable stimulation group were responders, 6% in the sham stimulation group and 0% in the medical management group. The differences between the responder rates in the treatment group and control groups were statistically significant. Other outcome measures, such as number of headache days, were not statistically significantly different between the groups. However, the percentage reduction in headache days was 27% for the treatment group and less than 9% for each control group, showing a numerical advantage for the treatment group. No unanticipated device adverse events were reported. Movement of the lead occurred in 24% of subjects. 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.{{cite journal, last1=Diener , author2=Dodick DW , author3=Goadsby PJ , author4=Lipton RB , author5=Olesen J , title=Chronic migraine—classification, characteristics and treatment, journal=Nature Reviews Neurology, year=2012, volume=8, pages=162–171, doi=10.1038/nrneurol.2012.13, pmid=22331030, first1=Hans-Christoph, issue=3 , s2cid=7858323 Patients were randomized into two groups. One group was a treatment group and received active stimulation. The other was a control group and received sham stimulation. Patients in the treatment group reduced their number of migraine days per month by 5.5 from a baseline of 20.2 days per month. Patients in the control group reduced their number of migraine days per month by 3.9 from a baseline of 19.2 days per month. The difference between the two groups was not statistically significant.

References

Migraine