Is Injection Therapy The Best Solution for Foot Neuromas?
The pure ethanol for injection comes in 1 ml vials and you would add two of these to the 48 ml of local anesthetic agent to create the dilute solution. Once you have sterilely prepared the solution, apply a new label to the bottle to prevent inadvertent local blocks with the sclerosing solution.
Given the viability of the mixed alcohol solution, it is my opinion that you can maintain it for at least six months. The three keys are protecting the bottle from direct sunlight exposure, maintaining the mixed solution in a closed multi-dose bottle and avoiding direct exposure to air. Once you mix the alcohol solution, you should date it in order to stay abreast of its shelf life. You can obtain small bottles of ethanol for injection from several suppliers or local pharmacists and mix the solution in your office to reduce costs.
Essential Pearls For Successful Outcomes
When injecting most nerve lesions (virgin neuromas, nerve entrapments or stump neuromas), you need to inject an adequate volume of the 4% alcohol sclerosing solution (usually 0.5 to 1.0 ml) proximal to the maximum point of tenderness. In other words, you shouldn’t do the injection into the actual neuroma or site of the nerve entrapment but ensure that it is more proximal to that point where the nerve is more likely to be ‘normal.’
This allows more of the dilute alcohol to be absorbed into the nerve tissue and, theoretically, there is more potential for nerve destruction with repeated injections. A local anesthetic nerve block is not necessary prior to injecting the 4% alcohol solution since this will make locating the involved nerve more difficult and may add further dilution to the injected alcohol solution.
You would give the injections weekly (five to 10 day-intervals), using a small syringe with a 1-1/4 inch, 27-gauge needle. Using the longer needle helps you ensure close placement of the injectable to the involved nerve tissue.
Repeat this injection process for three to seven visits. If the patient is totally symptom-free after three injections, then you can discontinue all treatments. If you see no improvements of symptoms after the third injection, I suggest trying one of the other alternative treatments.
On the other hand, if you see some decrease in symptoms following the third injection, I suggest continuing for the duration of seven injections. After you’ve given the full series of seven injections, it is advisable to wait approximately 90 days before deciding upon further treatment since many cases will continue to show gradual improvement afterward. This may be due to continued degeneration of the involved nerve and, ultimately, successful chemical neurolysis.
Case Study 1: When Orthotics
And A Cortisone Injection Fall Short
A 32-year-old female patient came in with a complaint of increasing burning and pain on the ball of the left foot. Over a 10-month period, she had changed her shoe styles, decreased her activity levels and used an over-the-counter foot massager with no improvement in symptoms. Another physician had recommended neuroma surgery but the patient was reluctant to pursue this approach, however she did believe the pain had grown worse with time.
During the clinical examination, I noted reproducible pain and radiating tingling into the third and fourth toes of her left foot with compression and direct palpation of the third intermetatarsal space. X-rays showed no abnormalities and the patient’s history was negative for contributory findings. I made a clinical diagnosis of intermetatarsal neuroma of the left foot.
I gave the patient a list of potential treatment options, including cortisone injection, orthotics devices, a series of alcohol sclerosing injections or nerve surgery. I recommended a cortisone injection and orthotic devices as the first line of treatment and she was agreeable. I gave the patient a cortisone injection (1 ml of dexamethasone plus 1 ml of local anesthetic agent) into the third intermetatarsal space at the point of maximum tenderness.
I then scheduled her for examination and casting for custom orthoses. After receiving the orthoses, the patient said she had experienced about one week of improvement following the cortisone injection. I instructed her to wear the orthoses for the next six weeks and to make a follow-up appointment.