Sclerosing alcohol injections for neuroma
What are sclerosing alcohol injections for neuroma?
Sclerosis (adjective) is defined as the hardening of soft tissues. Sclerosing (verb) in the act of making soft tissues hardened.
When applied to neuromas, sclerosing is the act of injecting an agent in order to kill the nerve without actually performing surgery to remove it. In order to achieve this, we used an injection of sclerosing alcohol.
Dehydrated alcohol
The medication injected is 98% ethyl alcohol that we purchase in 1 cc vials, called dehydrated alcohol. We then mix this with Bupivacaine local anesthesia in order to create a diluted solution. The percentage of alcohol to anesthesia varies.
The first articles and studies were performed using a 4% diluted alcohol solution. Subsequent studies showed that results often improved by increasing the concentration of alcohol in the diluted solution. These early studies showed up to an 80% success rate. We vary the percentage of alcohol depending on how the patient responds to the first injections. We usually start with a concentration higher than 4% and increase it with each subsequent injection.
Chemical neurolysis techniques
‘Chemical neurolysis’ refers to the killing of the nerve using a chemical (alcohol). This procedure is performed in the office and consist of an injection just proximal to, and around the neuroma. The alcohol penetrates into the nerve tissue and causes degeneration and atrophy of the nerve. The desired effect is to reduce and eliminate all of the function of the nerve.
This procedure requires multiple injections. At minimum, we have performed 3 injections that have completely caused the nerve to degenerate and cease all function. Often, it usually requires 3-7 injections in order to achieve this goal, and rarely up to 10. Injections are performed at 2-week intervals in order to allow the medication to work, observe the effects, and see if more injections are necessary.
Ultrasound-guided injection
In order to ensure exact placement of the injection, we use diagnostic ultrasound to visualize the neuroma and the needle as it enters the foot. This ensures that we are injecting the alcohol mixture in the exact correct spot.
Is the sclerosing alcohol injection procedure painful?
Many patients have told us that while we are performing the sclerosing alcohol injections they are less painful than a steroid injection for neuroma. The local anesthesia works very rapidly to create numbness such that patients do not feel any burn from the alcohol. After the anesthesia wears off, some patients will experience a burning sensation as the alcohol is working. Almost all patients describe this as minor pain. We look at this minor pain as a good indicator that the alcohol is working and doing its job.
What to expect after a sclerosing alcohol injection
Other than minor pain at the injection site, many patients tell us that they feel sequentially increased numbness in the adjacent toes distal to the neuroma. As previously discussed in our ‘neuroma causes page’, the function of the intermetatarsal nerve is to allow one to feel sensation on one side of each adjacent toe. As the alcohol injections progress to sclerose the nerve, sensation diminishes and numbness increases. Virtually all patients have told us that the numbness in the toes is negligible, and they would take the numbness over the pain that they were experiencing any day.
Long-term effects of sclerosing alcohol injections
After 3-7 injections, if this procedure is successful, the pain will be resolved and there will usually be slight numbness in the area of the neuroma and distally in the digits. The majority of patients report that the numbness usually goes away in 6-12 months. Localized sensation often comes back, either partially or completely, however, the pain does not usually come back.
In our experience, it is very rare for the pain, to return to the area once it goes away. Out of all the many patients that we have performed this procedure on, only one has ever returned after about a year with recurrent pain. A second round of injections resolved the pain, and the pain never returned.
Possible complications of sclerosing alcohol injections for neuroma
Although I would not consider this a complication, failure to alleviate the neuroma pain is possible. This procedure does not work on every patient. In our experience, this procedure is successful, meaning it reduces the pain such that no additional treatment is sought, approximately 60-70% of the time. Fortunately, after performing this procedure, all of the other treatments that we do are not contraindicated. When this procedure fails, we go on to other minimally invasive procedures or open surgery.
This is a very safe procedure with very few complications. In rare circumstances, one may experience:
- Irritation of the nerve with increased pain - rarely, some patients have told us that they have increased pain after this procedure. Subsequently, I have gone on to perform additional treatments that have alleviated this increased pain.
- Atrophy of soft tissues with notable indent in the skin - on rare occasion, there may be atrophy of the soft tissues under the skin which results in an indent under the skin. In almost all occurrences, this goes away in a few months.
- Burning pain - some patients may experience temporary increased burning pain at the neuroma. I would not call this a complication as it indicates that the alcohol is working in order to sclerose the nerve. It almost all occurrences, the burning pain resolves with time. In the rare circumstances where the burning pain did not go away, our patients went on to additional invasive procedures which alleviated the pain.
- Localized redness and swelling - redness and swelling have been observed after the injection that lasted a few days. Inflammation is caused as the alcohol starts to work in order to sclerose the nerve. Although we have never seen it clinically, it is possible that bacteria can be introduced into the skin through the injection site. This may also cause localized redness and swelling. Obviously, precautions are taken to avoid this by using topical alcohol on the skin prior to the injection, as well as using sterile injectables, needle and syringe supplies.
Post procedure instructions after sclerosing alcohol injection
We advise patient to go home right after the procedure is performed, elevate the foot and rest. Normally, anesthesia will wear off in 6 to 24 hours. We advise patient to stay off their feet for the first 6-12 hours. After this, there are no restrictions to activity level. We advise patient to return to activity to their tolerance. If they are experiencing burning or pain, we advise them to rest and apply ice. If this does not alleviate the pain, they may take a nonsteroidal inflammatory medication to alleviate some of the inflammation. In rare cases, if pain is severe or persists longer, we ask patients to call and return to our office for evaluation.
Are sclerosing alcohol injections covered by insurance?
Sclerosing alcohol injections for the treatment of neuromas is covered by most insurances. The medical terminology for medical billing is: “neurolysis by chemical agent”.
Conclusion
Sclerosing alcohol injections for the treatment of neuromas are a viable treatment option when less invasive, conservative therapy fails. While they do not work for all patients, they do not prevent us from performing additional procedures subsequently if they do fail. With rare and very little complications and side effects, they are an excellent treatment option that may prevent the need for open neuroma surgery. Our expert physicians will discuss alternatives with each patient, and together, make the decision on which procedure is right for them.