As awareness of “migraine surgery” increases, I have often been confronted by the question of whether the nerves that are involved need to be cut for the procedure to be effective. The answer to this question is “sometimes”, but let me elaborate in the next few sentences. There generally seems to be two perspectives on how to deal with "smaller" sensory nerves, in other words those with relatively small areas of sensory distribution. One approach would postulate that cutting the nerve oftentimes leaves a small area of numbness which is easily tolerated or is not even appreciated by the patient and therefore is a relatively good trade-off for relief of pain. Another perspective is that if the nerve is viable as noted during surgery, then leaving it intact will hopefully allow good relief of pain and preservation of sensation. Each of these approaches has its advantages and its disadvantages. Cutting the nerve can lead to immediate relief, but often leaves a noticeable area of numbness. Leaving the nerve intact requires the nerve to heal, recover and/or regenerate from the compression/irritation which was present as the cause for the surgical procedure. This process often requires several months depending on the longevity and severity of the compression/irritation, but if successful should lead to decreased pain and a preservation of some degree of sensitivity. Both procedures carry a small risk that nerve recovery will not occur and pain may persist. In the case of a cut nerve, the proximal (upstream) nerve end may remain persistently sensitive thus leading to a "phantom limb" type of sensation despite numbness in the former area of distribution. In the case of a decompressed nerve, the nerve may not regenerate again leading to persistent discomfort. Moreover, both procedures carry a small risk of neuroma formation although I personally believe that this risk is slightly less when nerves are left intact as compared to when they are cut.
I was recently notified that my study on lesser occipital nerve decompression as opposed to excision for chronic headaches was accepted for presentation at the American Society of Peripheral Nerve Annual Meeting in January. In this study, I followed 23 patients for just over one year and analyzed their headache frequency, duration and severity according to a well-established instrument known as the Migraine Headache Index (MHI). After surgical decompression leaving the nerves intact, MHI scores were statistically significantly improved post-operatively (126.3 to 25.5) with 8 patients (35%) reporting complete resolution of their headaches. One patient had persistent discomfort and required excision of the lesser occipital nerve and after that secondary procedure, she achieved a 73% reduction in her MHI score (88 to 24). All of the patients reported grossly normal sensation in the relevant nerve distribution and no symptoms suggestive of neuroma formation. There were no complications.
Admittedly, this is a very small study involving only one surgeon so further studies need to be performed. However, I believe that it demonstrates the utility of leaving nerves intact when they are deemed to be viable. Doing so, often leads to sensory preservation and results which are just as effective as nerve excision with few complications. In other words, I believe in restoring the anatomy damaged by trauma or bad luck and allowing the body to heal itself.