Cryosurgery Or Sclerosing Injections: Which Is Better For Neuromas?
Clinical Exam Keys To Identifying
Before embarking on any treatment plan, one must correctly diagnose intermetatarsal neuromas as forefoot pain can be caused by a variety of conditions.
When patients have an intermetatarsal neuroma, the typical presenting complaint includes pain or tingling in the ball of the foot with ambulation and occasional radiation to the digits. These symptoms are most common in the third interspace, followed by the second interspace, and infrequently in the first or fourth interspace. Patients tend to relate an increase in symptoms when they wear dress shoes, especially high heels. They will often have relief of these symptoms when they cease wearing the dress shoes or when they wear more supportive shoes. Patients may describe the pain as burning, tingling, shooting or they may say it feels like a bruised region in the forefoot. Also be aware that similar symptoms may return after the removal of a previously treated neuroma or following trauma to a nerve.
While the key finding from the clinical exam is pain in the interspace at the level of the deep transverse intermetatarsal ligament, be aware that you will sometimes see edema in this region. Also keep in mind that these patients will usually have no pain directly plantar to the metatarsal heads.
In order to reproduce the patient’s symptoms, one should dorsiflex the digits and palpate the deep intermetatarsal ligament. Dorsal-plantar palpation of the interspace with compression of the medial and lateral aspects of the foot often allows palpation of an inflamed nerve. This palpable “click” is commonly called Mulder’s sign.13 One may also pursue diagnostic testing to either confirm your clinical diagnosis or rule out a variety of differential diagnoses.14
How To Perform Alcohol Sclerosing Injections
If initial conservative therapy in the form of orthotics, shoe modifications and/or physical therapy modalities has failed, one should consider sclerosing injections with dehydrated alcohol.
Prior to initiating this therapy, inform patients that you will be giving them three serial injections and will evaluate success based on their clinical response. Let them know that they may receive up to seven injections. Caution them that pain is often associated with the initial injection due to the induced damage to the nerve but this typically resolves with subsequent injections.
In order to prepare the injection solution, one would mix 48 ml of 0.5% bupivicaine HCl with epinephrine with 2 ml of dehydrated alcohol. This produces a 50 ml solution of 4% sclerosing solution, which is good for three months.
Initially, one should mark the point of maximum tenderness at the region of the neuroma “bulb.” Proceed to introduce the 1.25-inch, 27-gauge needle dorsally and manipulate it until the patient experiences pain and radiation to one or both toes. At this point, you should proceed to inject 0.5 cc of 4% sclerosing solution into the intermetatarsal nerve. One would subsequently perform injections every five to 10 days. In my experience, it averages out to every seven days.
If you appreciate skin or soft tissue atrophy plantarly, discontinue the injections.
One should follow up with the patients one month after the final injection to determine short-term success and give them instructions to follow up if they have persisting symptoms. Encourage functional support throughout the injection and post-injection process. If sclerosing injections fail to provide relief, one should proceed to discuss surgical intervention with the patient in order to alleviate his or her symptoms.
In my experience, I have found that using sclerosing injections with dehydrated alcohol is an excellent alternative to surgical excision or release in treating both primary and recurrent neuromas.
Dr. Peebles is a Fellow of the American College of Foot and Ankle Surgeons, and is on the faculty of the Podiatry Institute.
1. Bennett GL, Graham CE, Mauldin DM: Morton’s interdigital neuroma: a comprehensive treatment protocol. Foot Ankle Int. 16:760-763, 1995.
2. Greenfield J, Rea J, Illfeld FW: Morton’s interdigital neuroma: indications for treatment by local injection versus surgery. Clin Orthop 185: 142-144, 1984.