The role of diagnostic block in the management of Morton's neuroma.

OBJECTIVE

To determine the outcome of surgical excision of Morton's neuroma after a local anesthetic diagnostic block into the neuroma has relieved symptoms.

DESIGN

A cohort study.

SETTING

A university affiliated hospital.

PATIENTS

A sequential series of 37 patients who underwent 41 excisions with at least 2 years' follow-up. Seven patients had undergone repeat excision of a neuroma, and 34 primary excisions were performed. Surgery was performed by a specialist in orthopedic surgery of the foot and ankle.

INTERVENTION

Excision of the Morton's neuroma after a positive diagnostic block.

MAIN OUTCOME MEASURES

Grade of symptoms at follow-up done by independent review on a 4-point scale.

RESULTS

Of 41 procedures, 11 had an unfavourable outcome: 4 procedures were graded 3, and 7 procedures were graded 4. Eight (24%) of the 34 primary procedures were reported as failures, and 3 (43%) of the 7 revision procedures were reported as failures. Most patients reported poor results owing to persistent pain.

CONCLUSIONS

Diagnostic blocks do not improve the results of surgery for excision of Morton's neuroma and are not recommended. Because failure rates are greater than 20%, surgery for Morton's neuroma should only be offered after a full course of nonoperative management.