One of the most common questions that I get from my patients when they come into the office to see if they are a candidate for nerve decompression surgery goes along the lines of, “Gee Doc, I hope you find something! What if you get in there and don’t find anything wrong? What will you do?”
I have never encountered a patient on the operating table where there hasn’t been some element of nerve compression. Sometimes this is seen in the form of how the occipital nerve interacts with the occipital artery where the latter wraps around the nerve a bit like an anaconda. Sometimes, compression can be caused by a spastic muscle and sometimes, compression can be caused when the connective tissue tunnel through which an occipital nerve passes in the neck to the base of the skull is excessively narrow.
While some element of compression has always been present, there are a couple of caveats to these observations:
- We don’t have an empirical method for measuring occipital nerve compression. If a patient suffers from a critical condition like compartment syndrome in the leg, in which when pressure builds up, there are established tools to measure what critical pressure is and when to operate. A similar baseline has yet to be established for nerve compression causing head pain, so there is no defined way to measure the degree or severity of the compression that we see.
- Secondly, we also don’t know what degree of compression will cause symptoms of pain. This amount of pressure will likely vary based on a number of parameters such as which nerve is involved. For example, the greater occipital nerve is a much larger and heartier nerve and therefore is likely to be able to tolerate more pressure before becoming symptomatic as compared with the lesser occipital nerve.
- Lastly, we don’t ever operate on people who don’t have symptoms nor where candidacy for surgery has been not been verified via history, physical examination and nerve blocks. In other words, when you only have symptoms on the right side, I’m not going to dissect and open the left side of the neck just to look so that I have a comparison of what “normal” supposedly looks like. Doing so exposes those left-sided nerves to potential injury unnecessarily. That being said, there was an important study conducted by Dr. Guyuron several years ago to validate the outcomes of headache surgery. It was what was known as a sham surgical trial, 76 patients knowingly participated with 49 patients undergoing the actual nerve decompression procedure and the remainder undergoing what’s called a sham operation. On the day of the surgery, Dr. Guyuron would open an envelope and it would tell him if the patient was having the real surgery or not. The sham surgeries had to seem like they could be real, so these patients were still induced under anesthesia, were cut open and their nerves exposed, but ultimately left alone for a typical time that the operation would take. The patients who had the actual surgery did statistically better in terms of frequency, severity and duration of their headaches when compared to the sham surgical patients. In addition, while there was some placebo effect, none of the patients who received the sham surgery were headache-free, while a statistically greater percentage in the actual surgical group did report this outcome.
The take home message is this: There is still much work to be done in order to establish a measurable baseline for nerve compression that leads to head pain. However, in the meantime we can work with what we know and that is if a patient experiences chronic pain, has exhausted all non-surgical methods of treatment and responds well to nerve blocks, they are reasonably good candidates for nerve decompression surgery.