Botox refers to botulinum toxin, which is a protein that is toxic to the nerves. It can be used in very small doses to treat painful muscle spasms and as a cosmetic treatment in some parts of the world. Injecting overactive muscles decreases muscle activity by blocking the release of acetylcholine. Acetylcholine is a neurotransmitter. Without it, the muscle is unable to contract for up to six months.
There was a recent study done comparing BTX-A injection with a placebo (saline injection) in patients with myofascial pain syndrome (MPS). MPS is a condition of muscular pain and spasm linked with trigger points (TrPs). TrPs are areas of hyperirritability in a muscle. They can cause local pain that is referred to other nearby areas in the body.
The researchers wanted to see if BTX-A can give some relief from painful symptoms. One group received an injection in muscles with TrPs. The other group got an injection of the saline solution. Results were compared by measuring patients' neck pain, body pain, function, and levels of disability.
They found that patients in both groups got equal relief from their neck pain. That suggests maybe the needling of the TrP was enough to make a difference. Other studies have shown a benefit of dry needling for TrPs, too. The BTX-A group did have better relief from bodily pain compared with the placebo group. Mental health was also improved in this treatment group.
As mentioned, BTX-A works by stopping the release of chemicals from the nerve endings where the nerve connects with the muscle. This site is called the neuromuscular junction. It's possible that there is another mechanism by which BTX-A works to cause pain relief. It may be that the BTX-A acts directly on the spinal interneurons to block nociceptor function. Nociceptors send messages of pain to the brain. Pain can be reduced by blocking these messages.
Botox is not used routinely for neck and back pain. These studies are investigating how effective this approach may be for patients with conditions such as MPS.