"My doctor told me that you can do a nerve block or kill a nerve to treat my pain"
This is a frequent patient's statement in a pain clinic. The words "nerve block" or "nerve ablation" can be misunderstood as being permanent solutions or at least offering permanent improvements to patients with chronic pain. Unfortunately, this is uncommonly the case. However, uncommonly does not mean never. Also, even temporary relief is a valuable goal in pain management.
Nerve blocks
Nerve blocks consist in injecting a local anesthetic, with or without steroids or other adjuncts, close to a nerve that is expected to transmit the patient's pain. Local anesthetics and any other medication do not remain permanently at the nerve, but are removed by the blood stream and eventually eliminated from the body. Because few hours or days of pain relief are not a valuable goal in chronic pain, are nerve blocks useful at all? The answer is yes, for reasons explained below, and more extensively in another blog.
Nerve ablations
An ablation consists in destroying a nerve by placing a needle close to a nerve and apply extreme heat (radiofrequency ablation), extreme cold (cryoablation), or chemical agents called "neurolytic", such as alcohol. If the nerve transmits the patient's pain, its ablation is expected to provide long-term pain relief. However, nerves grow back, which leads in most cases to return of pain after a variable period, typically 3-12 months. Therefore, also ablations are not permanent solutions.
Temporary pain relief can be valuable
Although the effect of nerve blocks and ablations does not last permanently in most cases, they can be repeated if the duration of pain relief is long enough to make the treatment worthy. The treatments are invasive, but in most cases associated with very low risks, and there may be no valuable alternatives. If patients experience improvement in their quality of life for some months, repeating periodically the procedures can be a sustainable option.
It's not only about pain relief
Monitoring different outcome domains, such as physical functioning, mood and sleep is essential for a shared decision between physician and patient about the benefits of repeated procedures as part of pain management. This has to be associated with addressing all relevant dimensions, including physical activity, body weight, sleep, and mood, among others. Disorders in these dimensions may persist even after interventional treatment, making the treatment only partially successful.
Long-term pain relief is possible
Although this does not apply to most patients, we occasionally see improvements that outlast the expected effect of the nerve blocks or ablations. This effect can be explained in different ways, as discussed more in details in another blog. The figure below illustrated two situations: the pain comes back when the effect wears off, or pain relief is sustained after the medication is eliminated or the nerves grow back after an ablation. In the second situation, possible explanations are outlined in the bullet list box. The temporary pain relief provides a window of opportunity, during which physical function, sleep, psychosocial issues and sensitivity of pain pathways can improve. These improvements can lead to less pain in the long term.
Comprehensive management is crucial
The above considerations, once again, stress the importance of non limiting pain management to reduction of pain signals arising from a body area. As explained in details in a previous blog, treatment of sleep disorder, psychological distress and disability may promote per se pain reduction. Not addressing these issues will reduce the chances of success of a procedure or shorten the duration of pain relief (as explained here).
To summarize:
Nerve blocks and ablations mostly produce temporary pain relief
They can be repeated if the duration of pain relief is long enough to justify risks, inconvenience, and costs
Pain relief lasting years is uncommon, but possible
Temporary pain relief provides the opportunity to reduce comorbidities that are of great relevance for the overall quality of life and that can improve the pain in the long term