Morton's Neuromas are inflammed swollen nerves in the front of your foot , usually found between the third and fourth metatarsals (as seen in the above MRI), and sometimes between the second and third metatarsals, and sometimes between both. You count the metatarsals from the big toe #1 to the pinky (baby) toe #5. The symptoms from these inflammed nerves are nerve symptoms: burning, tingling, numbness, electrical, radiating, buzzing, sharp, and/or feeling like a rolled up sock. They are abnormal sensations, also called dyskinesias (just to show you how smart I am). But, this pain may be not be from the foot at all. Nerve pain in the foot can originate from nerve irritation at the ankle, knee, hip, or low back. Nerve pain in the foot can also be systemic (from the body) called peripheral neuropathy. So, it can be very challenging to diagnosis the source of pain in many patients, and thus treat it properly. Any workup for nerve symptoms in the foot should look for possible causes other than the foot.
One of the mainstay treatments of Morton's Neuromas involves injections. There are three common shots, and other combinations of medications used in injection form. First of all, there is the diagnostic injection of local anesthesia (like novacaine) to see if injecting the nerve gives complete pain relief. It sometimes proves that the nerve the doctor thought was the problem really is not the problem. These local anesthetic injections should be given with medications that last around 5 hours (commonly Sensorcaine, Marcaine, or Bupivacaine) so that the patient can be 100% sure of the relief attained--100%, 80%, 50%, 30%, or 0%. I am a big believer in this method of identifying the right nerve, if it is a nerve at all, since you only inject the nerve and not the tendons, ligaments, joints, etc. Sometimes, even though you are giving an injection which should last 5 hours, since you are blocking the pain cycle, the relief can be much, much longer. Many doctors will give these injections once or twice a week until the severe pain cycle is completely broken down and the symptoms greatly minimized.
The second most common type of injection involves cortisone. No one knows for sure how much should be given, since that varies from person to person and body part to body part, but I have lived by the rule of no more than 5 shots per year. I can count on one hand how many patients have needed more than 3 per year, so 4 or 5 shots is unusual, but sometimes necessary. Each one of my cortisone shots is 10mg of long acting steriod. Long acting means that some of the medication is still working for 9 months. As the crystal dissolves, there is slowly less cortisone working on a daily basis. Cortisone can allow healing to occur since it removes swelling. Swelling is our enemy. Swelling cuts off the normal circulation to an area inhibiting healing. So it it more than just a bandaid or temporary fix--it can fix the problem!! I find no use for short acting cortisone. It only lasts for 3 days or so. So what? If you think the patient needs cortisone, use the good stuff. I once had a patient come in for surgical consultation after she failed to improve with 10 cortisone injections over a 6 month period. Surgery had been recommended, and I was a simple appointment to verify that this was appropriate. When we found out what the doctor had used in each injection, I was dumbfounded. He was using long acting cortisone, but in a homeopathic dose of 0.1mg per shot. If you do the math, you would realize that it would take him 100 shots to equal the dosage of one of my shots. Oh my!!??!!
Why am I discussing dose? Because you should know if you are getting a foot or ankle shot, if it is long or short-acting cortisone, and how much? The 5 dose recommendation per year is based on actually getting 50 mg of long acting cortisone in one area. It does not mean that you can not get the same amount in another area of your foot. One smart patient, with one smart doctor, helped me understand that a local cortisone shot can affect the entire body since small amounts do get absorbed into the body. I call this Dorothy's Rule, after one of my patients, that a patient should not get more than 1 shot of long acting cortisone per month for their entire body. I like this rule since cortisone does affect us in many ways. This applies to patients whom are getting cortisone shots for their foot, and at the same time for their knee, shoulder, etc.
When giving cortisone shots the doctor should stay away from the skin, buring the injection as deep as possible, and avoid tendons if possible. Cortisone near a tendon can weaken it, and cause tearing, as it can thin the skin. The skin usually gradually gets healthy, but can take 9 months or longer, and can not tolerate further shots at this time. Cortisone is normally mixed with the long acting local anesthetics to get 5 hours of post shot pain relief. If the patient does not feel any relief after the shot, the shot missed the painful spot. After cortisone, patients are told no running or jumping for 2 weeks (another reason athletes hate cortisone shots). The patients are told to check pain relief in the first 5 hours, at a week, and at the 2 week followup. If the 10mg is not enough (with the goal 80% reduction in pain), a second shot is given and the two weeks starts over again. During these shots, I do not have the patient go to physical therapy, but they can cross train with non jumping and running activities. With many activities like cycling, they have to assess if it has a negative impact on them. During these shots, the patients are told to ice the area 3 times daily (see separate post on icing). At each two week interval, if the patient seems to be at the 80% level (familiarize yourself with a pain chart and read the separate post on the Magical 80% Rule), activity is gradually returned. Hopefully, the doctor and patient have learned what to avoid, what to wear in the shoes, how to tape, etc, to minimize the re-irritatation during the return to activity program. Any cortisone shot after the first shot in the 9 month window of time is considered a booster shot.