Contribution of a new electrophysiologic test to Morton's neuroma diagnosis

Rare entrapment neuropathies of the lower extremity: A narrative review

Lower limb entrapment neuropathies comprise a wide range of disorders, including less common conditions like tarsal tunnel syndrome, Morton neuroma, obturator nerve entrapment syndrome, superior gluteal nerve entrapment, and cluneal nerve entrapment syndrome. Despite being less prevalent, these syndromes are equally significant, presenting with symptoms such as pain, dysesthesia, muscular weakness, and distinct physical signs. Accurate diagnosis of these less common disorders is crucial for successful therapy and patient recovery, as they can sometimes be mistaken for lumbar plexopathies, radiculopathies, or musculotendinous diseases. This narrative review highlights the significance of identifying and diagnosing these particular neuropathies through a comprehensive assessment of the patient's medical history, detailed physical examination, and the use of electrodiagnostic and/or ultrasound investigations. When the diagnosis is uncertain, advanced imaging techniques like magnetic resonance neurography or magnetic resonance imaging are necessary to confirm the diagnosis. A positive diagnosis ensures prompt and targeted treatments, preventing further nerve impairments and muscle wasting. This article explores the epidemiology, anatomy, pathophysiology, etiology, clinical presentation, and electrodiagnostic interpretation of lower limb entrapment neuropathies, highlighting the importance of precise diagnosis in achieving favorable patient outcomes.

Improved Injection Technique of Ethanol for Morton's Neuroma

BACKGROUND

Morton's neuroma is a common cause of forefoot pain. Various conservative methods (injections of various pharmacologic agents) have been published with an outcome of 6%-75% success rate (free of pain in daily life) per injection. The aim of the present study was to assess the outcome of an improved localization technique, a higher dosage, and a higher percentage of ethanol.

METHODS

Using fluoroscopic and electroneurographic guidance, 2.5 mL of 70% ethanol were injected into 33 feet with a magnetic resonance imaging (MRI)-verified neuroma. We evaluated patients at up to 5-year follow-up.

RESULTS

A "success rate" of more than 82% per single injection (defined as free of pain in daily life) was achieved and no recurrence was seen over 5 years. All scores (visual analog scale; Short Form-36 subscales, American Orthopaedic Foot & Ankle Society ankle-hindfoot score) showed significant improvement (P < .0001). Mean 1.2 injections were necessary. No significant side effects were seen. However, some mild pain persisted in some patients who participated in sports.

CONCLUSION

The injection of 2.5 mL of 70% ethanol under fluoroscopic and electroneurographic guidance was a safe method for the treatment of MRI-verified Morton's neuromas. Combining the effect of a higher percentage of alcohol and a higher dosage and an improved localization technique resulted in a high rate of patients without pain.

LEVEL OF EVIDENCE

Level IV, cases series, prospective.