We had a very successful “soft opening” to our Facebook Live series of events, which we hope to be able to do with some frequency in the future. After we went ‘off the air’, many people contacted us who didn't get a chance to ask their questions live. I have decided to address a few of these over the next few weeks.
One of the more interesting questions that I would like to address now is: Have you cut the nerves and attached them to another rather than bury them? What was the outcome?
What I tell my patients pre-operatively is that I will often make a ‘game time’ decision as to whether or not any particular nerve I am operating on can be saved or if it needs to be transected. That is because one can never predict what one will find once the nerve has been exposed - if it is too badly damaged, a decompression alone will not suffice. As I have mentioned in a previous blog post (Lions & Tigers & Neuromas…Oh my! – Nov 21, 2017), there are several possible options if a neuroma forms following a nerve transection and the same principles apply to a nerve that has just been cut on purpose:
- The cut nerve end can simply be freshened and implanted into the local muscle.
- The transected nerve end can be connected to a long, cadaveric nerve graft (i.e. an allograft). In this case, the surgeon would be utilizing the principle of distance in that it is unlikely the cut nerve would actually grow all the way through the entire graft and hence the end of the allograft would be passive and unlikely to cause pain.
- The nerve can be “re-innervated” via a procedure where the nerve is repaired end-to-side or end-to-end to another sensory (or perhaps even motor) nerve. This ‘re-innervation’ procedure is often used to help amputees power the newer myoelectric/bionic prosthetics that appear on the news from time to time and can also be used during migraine surgery.
It is almost always possible to find another nerve (let’s call it the recipient nerve), adjacent to the nerve that has been cut (let’s call that one the donor nerve), to attach the cut nerve to. However, any time one operates on any nerve, there is always a possibility that the nerve being manipulated may be injured. Therefore, the surgeon must recognize the possible negative outcomes if the recipient nerve becomes damaged. After all, the recipient nerve, is presumably a normal nerve with no pathology relevant to the condition being treated.
If the recipient nerve is a purely sensory nerve and is injured inadvertently, then possible negative outcomes from damage to that nerve include decreased sensation, complete numbness, or chronic pain in a new location. If the recipient nerve is a purely motor nerve and is injured inadvertently, then the patient may experience weakness or even complete paralysis of the muscle which that nerve supplies.
Many of the recipient nerves in the neck region are motor nerves. If, for example, the greater occipital nerve is too damaged and must be cut, one can find a local motor nerve to which to attach it, but if that motor nerve is injured and stops working then the patient might experience neck weakness and may be unable to fully extend their neck. Therefore, in my humble opinion, if the surgeon is planning on manipulating those motor nerves, it should only be because there is no other option available to prevent a neuroma.
Since the other options noted above are readily available and often successful, I have never personally had to attach a cut occipital nerve to a recipient motor or sensory nerve. There are also no data on success rates with such re-innervation procedures for the treatment of chronic headaches. The take home message is as always - please have a frank discussion with your surgeon about what s/he is planning on doing if a nerve is too badly damaged and decompression may not be successful.