Point-Counterpoint: Intermetatarsal Neuromas: Is Neurectomy The Best Option?

By Patrick A. DeHeer, DPM, and Bruce Werber, DPM

   Yes. By Patrick A. DeHeer, DPM. While this author has had success with conservative treatment, particularly sclerosing therapy, he emphasizes that a plantar approach to the neurectomy can be effective when surgery is indicated.    Morton’s neuroma is a commonly encountered forefoot pathology that has many different treatment options available for the foot and ankle specialist. What are these options, when does one implement each type of treatment and when does surgical intervention become the best option for the patient?    Before looking at any treatment options, it is of vital importance to confirm the diagnosis of Morton’s neuroma as many forefoot pathologies can mimic the symptoms. Accordingly, one must work through the differential diagnosis. It is well documented in the literature that clinicians should include conditions such as lumbar radiculopathy, tarsal tunnel syndrome, stress fracture, calluses, Freiberg’s infarction, peripheral neuropathy, bursitis, rheumatoid arthritis, metatarsophalangeal joint disorders and tumors in the differential diagnosis.

Essential Diagnostic Pointers

   When it comes to diagnosing Morton’s neuroma, clinicians should base the diagnosis on the patient’s history and physical findings, and subsequently confirm it with at least one diagnostic injection. The patient’s history is often enough to direct the experienced foot and ankle surgeon to the correct diagnosis, especially when one utilizes the NLDOCAT (nature, location, duration, onset, course, aggravation and treatment) chief complaints approach during the interview process.    In the physical examination, a positive Mulder’s sign is the traditional indicator of a Morton’s neuroma. Although the literature shows marginal reliability of the Mulder’s sign, I have found it to be very helpful in the clinical diagnosis.    In the literature, Gauthier’s test is reportedly highly sensitive for nerve compression syndrome. This test consists of compression of the metatarsal heads while actively dorsiflexing and plantarflexing the digits for 30 seconds. A positive test results in pain to the patient or a sensory abnormality.    It is very important to examine the adjacent metatarsal joints to rule out any potential joint pathology, especially predislocation syndrome or metatarsalgia. When working through the differential diagnosis of a Morton’s neuroma, radiographic examination is indicated to rule out any potential osseous pathology.

Using Diagnostic Injections To Guide Treatment Decisions

   After making the differential diagnosis of Morton’s neuroma, it is of utmost importance to confirm the diagnosis with a diagnostic nerve injection. I like to inject 0.5 cc of xylocaine and 0.5 cc of dexamethasone phosphate in the involved innerspace just behind the toe sulcus. Then one can ask the patient to ambulate in the office setting and record his or her initial response. The patient will track the injection results over approximately one week. At the end of the week, the patient usually returns for a follow-up visit.    The subsequent treatment is based on the patient’s response to the injection. The patient will usually have one of four findings: no change, better while numb, better for two to three days, better for the entire time. If there is no change, reconsider the diagnosis.    If the patient feels better while numb or better for two or three days, I start the patients on sclerosing therapy as described by Dockery. I have used this treatment for the past five to six years with 80 to 85 percent success rates, similar to those reported by Dockery.1    If the patient responds with sustained pain relief from the initial diagnostic nerve injection, I tend to follow with oral steroids and orthoses. If at any time the patient is not progressing with this treatment, I will initiate sclerosing therapy as above. In regard to orthoses, it has been my experience that unless the neuroma is asymptomatic, the symptoms tend to be aggravated by the device. I have tried several different styles of orthoses with many different modifications and found this to be a consistent finding through the years.

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