Compare Ultrasound Assisted Cold Therapy and Lidocaine Injection to Treat Morton's Neuroma

A 3-arm Randomized Controlled Study Comparing Ultrasound-guided Cryoablation, Ultrasound-guided Perineural Lidocaine and Ultrasound-guided Perineural Saline to Treat Intermetatarsal Neuroma

The purpose of this study is to evaluate the effectiveness of a device that delivers freezing temperature compared to injecting lidocaine (an anesthetic medication) in providing pain relief to patients with disorganized nerve bundle between the toes, also known as Morton's neuroma. The same ultrasound technology that the obstetricians use to visualize a fetus inside a pregnant woman will be used to help the study physician to locate the Morton's neuroma while precisely delivering the freezing temperature and lidocaine near the nerve.

This study will be a 3-arm randomized single-blinded placebo controlled study in which human subjects with intermetatarsal neuralgia will receive subcutaneous normal saline or subcutaneous lidocaine or ultrasound guided cryoablation. The first follow up will take place 4 weeks post procedure to monitor the magnitude and duration of pain relief. Subjects will then be crossed over. Those who had received saline or lidocaine will receive ultrasound guided cryoablation. Individuals, who had previously been given ultrasound guided cryoablation without any improvement, may opt for another denervation procedure at 4 weeks. All of the participants will be followed up at 3 months post procedure to determine the magnitude and duration of pain relief.

Study procedures will be conducted by the principle investigator who is a Board Certified pain management attending physician and an expert in performing ultrasonography guided interventions The cryoablation device is routinely used to treat various painful pathologies at Mount Sinai and Beth Israel pain management offices. The device manual and instructions will be available at both locations. All research staff has prior experience working with individuals with foot and ankle injuries at Mount Sinai.

Inclusion Criteria:

• Between the ages of 18 and 80 years old
• Magnetic Resonance Imaging (MRI) confirmed diagnosis of Morton's neuroma - Refractory (greater than 3 month) symptoms to multiple conservative management, including physical therapy, nonsteroidal anti-inflammatory drugs (NSAIDS) and foot orthotics.
• No history of systemic inflammatory conditions such as rheumatoid arthritis
• Able to give written informed consent - Subject has been on a stable dose of analgesic mediation (or not on analgesic medication) for at least 3 weeks and is agreeable to remaining on current regimen for the duration of the study.

Exclusion Criteria:

• Diagnosed complex regional pain syndrome (CRPS)
• Pregnancy - History of intolerance, hypersensitivity or known allergy to lidocaine - Recent history of recent surgical intermetatarsal neuronectomy (within previous 6 months) - Coagulation disorder - Current infection
• Intermetatarsal bursitis
• Metatarsophalangeal joint instability/capsulitis
• Metatarsal stress fracture
• Lumbar radiculopathy
• Tarsal tunnel syndrome
• Frieberg's infraction
• Painful callosities associated with toe deformities
• Peripheral neuropathy
• Diabetes mellitus and peripheral vascular diseases
• Insufficient command of English to complete self-¬report instruments.