An intermetatarsal neuroma is any irritative process of the common digital nerve branch that supplies the plantar (bottom) of adjacent toes. It most commonly involves the nerve that supplies sensation to adjacent sides of the third and fourth toes, but can also affect other toes of the foot.
A neuroma is not cancerous and is not a true tumor but a reactive, degenerative process such as a scar. Therefore, a neuroma is benign inflammation (enlargement) of the nerve.
Neuromas occur in all adults and are most common in females. Several factors contribute to its occurrence:
- High heeled shoes
- inflammatory conditions such as arthritis
- repetitive trauma from stresses incurred in occupational and recreational activities.
Any condition that causes constriction or irritation to the nerve can lead to the development of a neuroma. As example, wearing shoes, especially dress shoes, causes significant squeezing of the forefoot. This, in turn, leads to compression of the nerves and eventually, a neuroma can form.
Note left X-Ray showing compression of forefoot bones
Aside from pain, patients may experience:
- tight feeling across fore-foot
- sensation of walking on a small pebble
Symptoms are aggravated by walking in shoes and relieved by removing shoes, massaging the foot, and rest. Continued pain at rest may suggest that the neuroma is worsening.
The primary goal of podiatric treatment is to reduce or eliminate symptoms, so patients can maintain a normal lifestyle.
Treatment may be surgical or non-surgical. Non-surgical treatment consists of treatments such as, steroid injections, sclerosing alcohol injections, changing shoe gear style, physical therapy and prescription orthosis. Injection therapy with 4% alcohol sclerosing agent has proven very successful in the treatment of intermetatarsal neuromas. A study from the November/December 1999 issue of The Journal of Foot & Ankle Surgery quoted an 89% success rate with the use of 4% alcohol sclerosing solution. Similar results in our podiatric practice has decreased the number of neuroma surgeries being performed. The decision to surgically intervene is based upon the patients symptoms, the judgment of your podiatric surgeon and your preference. A neurectomy or surgical excision of a neuroma is performed when conservative treatment proves ineffective.
Neuromas have typically been very challenging to treat. Whenever we are dealing with a nerve, any treatment must be aimed at not causing additional irritation. In the late part of the 1990’s we began to read reports of a new treatment for this tough problem.
A novel approach was being taken, where a dilute solution of alcohol was injected into the diseased nerve. Initial reports at scientific meetings were promising. After publication of the Dr. Dockery’s work confirming success of the new technique, Drs. Richard Perez and Walter Strash became the first podiatrist in San Antonio to offer this new technique.
Following the recognized protocol, we achieved similar success to what was described in the study. Since that time, we have also incorporated the use of diagnostic ultrasound, which allows direct visualization of the nerve bundle.
The alcohol solution is injected into the nerve on a weekly basis. The alcohol molecules displace the abundant water molecules present within the nerve fibers. This has the affect of slowly shrinking the nerve. And with time, the symptoms disappear.
- The patient will require 7 weekly injection of 4% ETOH. These are performed under ultrasound guidance, as the medicine is infiltrated directly into the nerve.
- During the treatment period, the patient can continue to participate in all activities, including sports.
- There is no restriction on shoe gear during treatment.
Studies report success rates (complete pain relief) of between 61% and 89%. All studies report few side effects.
- Efficacy of chemical neurolysis for the treatment of interdigital nerve compression of the foot: a retrospective study. Mozena JD, Clifford JT. J Am Podiatr Med Assoc. 2007 May-Jun;97(3):203-6.
- Treatment of Morton's neuroma with alcohol injection under sonographic guidance: follow-up of 101 cases. Hughes RJ, AJR Am J Roentgenol. 2007 Jun;188(6):1535-9.
- The treatment of intermetatarsal neuromas with 4% alcohol sclerosing injections. Dockery, GL. Foot Ankle Surg. 1999 Nov-Dec;38(6):403-8.