Occipital nerve stimulation (ONS) is a medical procedure involving the implantation of a small device to deliver mild electrical impulses to specific nerves, aiming to alleviate chronic pain, particularly in the head and neck region. The device, similar to a pacemaker, is placed under the skin and connected to thin wires that stimulate the occipital nerves. This approach offers a reversible and non-destructive option for individuals experiencing persistent pain.
How Occipital Nerve Stimulation Works
Occipital nerve stimulation provides pain relief by modulating nerve signals before they reach the brain. The implanted device sends electrical impulses to the greater and lesser occipital nerves, which are located at the back of the head. These impulses are thought to disrupt abnormal pain signals, essentially “masking” them rather than completely blocking them.
The precise mechanisms by which ONS works are still being fully understood, but current theories suggest it involves influencing the trigeminocervical complex and activating the pain gate control theory. This means the electrical currents alter how pain is perceived, rather than destroying the nerves themselves. The stimulation can also affect local blood flow and neurochemical processes in the peripheral and central nervous systems, further contributing to pain reduction.
Conditions Treated by Occipital Nerve Stimulation
Occipital nerve stimulation is frequently considered for various chronic pain conditions, especially when other treatments have not been successful. It is commonly used for chronic migraine, a condition characterized by headaches occurring 15 or more days per month for over three months. ONS can help reduce headache days, pain intensity, and migraine-related disability for these patients.
The therapy also addresses cluster headache, which involves sudden, excruciating headaches affecting one side of the head and eye. Occipital neuralgia, a condition causing pain in the back of the head, upper neck, and behind the eyes due to irritated occipital nerves, is another primary indication for ONS. Cervicogenic headache, originating from the neck, and post-traumatic pain, including whiplash-related headaches, may also respond to this treatment.
The Occipital Nerve Stimulation Procedure
The occipital nerve stimulation procedure unfolds in two distinct phases: a trial period followed by a permanent implantation if the trial proves successful. The initial trial phase helps determine if the stimulation will effectively reduce pain. During this stage, temporary leads are carefully placed under the skin in the occipital region under local anesthesia with sedation, allowing the patient to provide feedback on sensation and pain coverage.
These temporary leads are connected to a small external stimulator, allowing the patient to experience the effects of the electrical impulses for approximately one to two weeks. Patients are encouraged to maintain a pain diary to track their pain levels and assess the effectiveness of the trial. If a significant reduction in pain, 50% or more, is reported, the patient may then proceed to permanent implantation.
The permanent implantation involves surgically placing the leads under the skin at the back of the head near the greater and lesser occipital nerves, under general anesthesia. These leads are then connected to a small, battery-powered pulse generator, similar to a cardiac pacemaker. This pulse generator is implanted in a subcutaneous pocket in the chest, abdomen, or upper buttock area.
After the permanent system is implanted, the neurostimulator is programmed by a qualified technician to optimize pain control, with adjustable settings for pulse width, amplitude, and frequency. Patients receive a handheld programmer to fine-tune the stimulation to their individual needs. The recovery period after the trial phase is minimal, allowing the patient to go home the same day. For permanent implantation, a hospital stay of one to two nights may be required, with careful attention to preventing infection at the incision sites.
Potential Considerations and Outcomes
Individuals considering occipital nerve stimulation should meet specific criteria, including having chronic, intractable headache disorders or neuropathic pain in the occipital or suboccipital region that has not responded to other treatments. A psychological evaluation may also be part of the patient selection process, and diagnostic occipital nerve blocks can help predict a patient’s potential response to ONS.
Regarding pain reduction, many individuals experience significant improvement, though not necessarily complete elimination of pain. Studies have shown that patients using ONS can see a reduction in the number of headache days and pain intensity, with some reporting around a 50% decrease in pain scores.
As with any invasive procedure, potential adverse events exist. These can include lead migration, a common technical complication. Infection at the implant site or around the pulse generator is also a possibility. Other potential occurrences include discomfort at the implant site, device malfunction, or a wearing off of pain relief over time.