Note on the pathology of Morton's metatarsalgia

Surgical approach to multiple interdigital nerve compressions

A surgical approach is described that permits access to 2 web spaces with a single incision along the common metatarsal, dividing distally at the proximal phalanx, as a novel y incision. This has been found to be useful in patients with adjoining interdigital nerve compressions.

Neuromas of the calcaneal nerves

A neuroma of a calcaneal nerve has never been reported. A series of 15 patients with heel pain due to a neuroma of a calcaneal nerve are reviewed. These patients previously had either a plantar fasciotomy (n = 4), calcaneal spur removal (n = 2), ankle fusion (n = 2), or tarsal tunnel decompression (n = 7). Neuromas occurred on calcaneal branches that arose from either the posterior tibial nerve (n = 1), lateral plantar nerve (n = 1), the medial plantar nerve (n = 9), or more than one of these nerves (n = 4). Operative approach was through an extended tarsal tunnel incision to permit identification of all calcaneal nerves. The neuroma was resected and implanted into the flexor hallucis longus muscle. Excellent relief of pain occurred in 60%, and good relief in 33%. One patient (17%) had no improvement and required resection of the lateral plantar nerve. Awareness that the heel may be innervated by multiple calcaneal branches suggests that surgery for heel pain of neural origin employ a surgical approach that permits identification of all possible calcaneal branches.

Treatment of recurrent neuroma of the interdigital nerve by implantation of the proximal nerve into muscle in the arch of the foot

A prospective study was done to evaluate the results of treating recurrent "Morton's" neuroma by a technique that combined resecting the interdigital neuroma through a plantar approach and implantation of the proximal end of the nerve into an intrinsic muscle in the arch of the foot. As a part of this study, quantitative sensory testing was done for the medial plantar and medial calcaneal nerves. Seventeen recurrent interdigital neuromas were resected in 13 patients. Pain was identified on physical examination as being due to neuromas located in the first (one), second (six), third, (eight) and fourth (two) web spaces. Seven of the 13 patients were found to have, by quantitative sensory testing and physical examination, an associated tarsal tunnel syndrome responsible for symptoms related to numbness in the foot in addition to the pain of the recurrent neuroma. These patients had tarsal tunnel decompression at the time of the neuroma resection. At a mean follow-up time of 33.8 months (range 24-42 months), done by direct physician interview and examination, 80% of the patients had excellent relief of symptoms, returned to their regular job, and wore usual footwear. Twenty percent of the patients had good relief of symptoms, worked at a different job, and had to change their footwear. It is concluded that recurrent pain after a dorsal interdigital neurectomy can be treated successfully through a plantar approach with implantation of the proximal end of the nerve into an intrinsic muscle. This study also identified an association of tarsal tunnel syndrome in 54% of this series of patients with recurrent Morton's neuroma.

Treatment of recurrent metatarsalgia by neuroma resection and muscle implantation: case report and proposed algorithm of management for Morton's "neuroma"

This report describes the theoretical basis for an approach to treating a recurrent Morton's "neuroma." The recurrence, being a true, classic neuroma, is treated by a technique validated in the treatment of the upper extremity painful neuroma: neuroma resection and muscle implantation. A plantar approach, implanting into the deep layer of intrinsics, was used. The three year success of this technique in a long-distance runner is reported.

Morton's neuroma: a microscopic evaluation

Microscopic evaluation of the interdigital neuroma is described in 24 nerves which were evaluated at six cross-section areas for size of the nerve and width of the perineural along with the fascicle diameter and the size and number of blood vessels inside each fascicle. A relationship was noted between the level of the distal edge of the intermetatarsal ligament. Cross-section that was taken at that area showed changes distally in nerve diameter, fascicle number and size, blood vessel number and size, and perineural width. These changes are consistent with the interdigital neuroma as an entrapment condition.

The intermetatarsal nerve: a microscopic evaluation

Microscopic evaluation of the interdigital neuroma is difficult because the appearance of the normal nerve has not been described precisely. In an effort to characterize the normal interdigital nerve, 104 nerves were removed at autopsy from the intermetatarsal spaces of 14 women who were more than 48 years old. A positive relationship between perineurial width and internal diameter of the nerve fascicle in web spaces 2, 3, and 4 was defined. In addition, the number and the diameter of blood vessels had a positive correlation in all web spaces. These measurements should be of help in the objective differentiation of the common interdigital neuroma from the normal interdigital nerve.