Migraine surgery has been developed over the past decade for the treatment of extracranial sensory nerve sites that have been identified as a specific foci or trigger for the headaches. The fundamental concept is that the cranial nerve branch is being compressed either by muscle, fascia or blood vessels. Surgical decompression clears the source of the nerve impingement resulting in decreased intensity and frequency of the migraine headaches. (arrows = greater occipital nerves decompressed)In rare cases it may even provide a complete cure of them.
But despite adequate decompression of the offending tissues, the development of postoperative scar can be a potential source of secondary nerve decompression. The initial migraine symptoms may subside but then recur weeks to months after the surgery. To prevent this potential postoperative concern, introducing projection of the nerve from recurrent scar has been advocated. The nerve an be wrapped with various materials such as collagen sponges, autologous fascia or allogeneic dermis.
Rather than nerve ‘wraps’, I prefer the concept of a soft tissue spacer. This is where a large volume graft is placed that provides maximum protection of the nerve from scar tissue by creating a large interface between the nerve and all of the surrounding soft tissues. This is done using a large dermal-fat graft that essentially fills most of the space from the cavity created by the nerve decompression up to almost the skin closure. Such dermal-fat grafts are well known to survive and create a soft tissue fill or spacer. This removes all doubt about any source of any source of secondary compression on the nerve.
Theoretically such fat grafts may also provide some favorable neurotrophic factors to decrease nerve irritation. Since fat is well known to be a rich source of stem cells as well as other nutrients they may have a positive influence on nerve recovery from chronic decompression. This is presumably one of the reasons fat injections for migraines has been advocated after failed nerve decompression surgery.
Dr. Barry Eppley