Neuroma and Forefoot Pain Part 2 of 3
Here’s what’s going on youtube: http://www.youtube.com/user/drmilo1121?feature=mhum#p/a/u/0/TIaC1ugEV8U
I was never very happy about the historical approach to neuroma, which is to surgically remove the nerve. For years I used decompression techniques which involved releasing the ligament connecting the metatarsals which is responsible for most of the pressure on the nerve. Release of this ligament was successful without cutting the nerve. Decompression or release of the nerve is also finding popularity in the treatment of diabetic neuropathy where literally all of the major nerves to the foot are examined and carefully decompressed. So ligamentous decompression, performed with a very small incision, has been a great option that’s been successful for years. You might be asking: What is the effect of cutting a ligament that joins the metatarsal heads? The answer is, usually only a small increase in the distance between the two metatarsal heads. But why change the structural anatomy of the foot if you don’t have to? So we next need to look at treating just the nerve itself.
Approximately 5 years ago, techniques directly treating the nerve proximal to the actual neuroma started to become popular. One such technique is the sterile alcohol injection. This injection is performed with a 4% sterile alcohol solution in Marcaine. Repeated injections are utilized and have a lasting effect on the myelin sheath of the nerve. The success of these injections are even more well-documented when a diagnostic ultrasound is used to guide the injection medication directly adjacent to the nerve. As with any injection technique, practice and refinement of technique are invaluable tools to keep patient’s comfortable and happy. To make these injections very comfortable for the patient, we used a small anesthetic block prior to the injection. The number of injections given is variable but usually between 5 and 7 and occur 2 weeks apart. Additional injections are considered if the patient(’)s response is encouraging but not complete. Additionally, raising the concentration of the percentage of alcohol from 4% to 8% or even 12% can be helpful.
My personal success with sterile alcohol injections is well documented in a book of success stories that we’ve been keeping for a number of years. The one problem with these injections is that it may take 3 or 4 injections before patients obtain relief. For this reason, I commonly implement a single additional procedure that is performed early in the treatment called cryo surgery.
Cryo-Neurolysis is the process of freezing a nerve branch in order to desensitize the nerve. This process has been in use for decades and has documented success. With the use of a good diagnostic ultrasound machine, the probe conducting the cryo-neurolytic agent, usually CO2 or N20 is placed directly adjacent to the pathologic nerve. I commonly perform these procedures on patients with Morton’s neuroma that are undergoing a series of sterile alcohol injections. The reason that I like to perform BOTH of these procedures is because the cryo-procedure is consistent and works quickly, but the anesthetic effect is sometimes not lasting due to the fact that cryosurgery does not permanently damage or destroy nerve tissue. I often like to paint a picture of going outside in minus 50 degree temperatures and touching your tongue to a metal pole. Of course your tongue will freeze to the pole until there was a thaw. After the thaw, your tongue would actually lose sensation and ability to taste on the portion that made contact with the pole. So in essence, cryotherapy provides a fast way to obtain relief of very painful Morton’s neuroma without a very large incision or the risk of stump neuroma. In fact, the incision is so small that you don’t even need a stitch. What’s even more encouraging is that patients actually go on hikes the day after the procedure and are completely pain free. While this is not always the post op course, it is fair to say that you can work out the very next day in over 90% of the cases. When we follow this with a series of sterile alcohol injections, we can complete the process and create a lasting cure.