Morton's neuroma is a common, paroxysmal neuralgia affecting the web spaces of the toes, typically the third.  The pain is often so debilitating that individuals become anxious about walking or even putting their foot to the ground.  Insoles, corticosteroid injections, excision of the nerve, transposition of the nerve and neurolysis of the nerve are commonly used treatments (Cochrane, 2004).

Medically Necessary:

Injections of sclerosing (neurolytic), anesthetic or steroid agents are considered medically necessary for treatment of Morton's neuroma when all of the following conservative therapies have failed:  

• Padding or orthotic devices (these can provide support to reduce pressure and compression on the nerve);
• Activity modification (to reduce repetitive pressure on the nerve);
• Changes in shoe wear (i.e., shoes with a wide box toe reduce compression of the metatarsal heads and reduce pressure on the nerve);
• Medications unless otherwise contraindicated (e.g., Non-steroidal anti-inflammatory drug (NSAIDs) which help reduce inflammation).

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

Typically, a neuroma is a benign tumor of a nerve characterized by exuberant proliferation of nerve endings. Morton's neuroma is not actually a tumor, but a thickening of the tissue that surrounds the digital nerve leading to the toes. It occurs as the nerve passes under the ligament connecting the toe bones (metatarsals) in the forefoot. The cause of Morton's neuroma is not clear and most frequently develops between the third and fourth toes. Possible etiologies include nerve entrapment, the aberrant anatomy of the plantar nerve in this location, structural/mechanical foot abnormalities, trauma or excessive pressure.

Multiple treatment approaches have been utilized for Morton's neuroma. These include conservative care, such as othotics, padding, and alternative shoe styles to relieve the pressure on the forefoot. More invasive treatments include sclerosing/anesthetic/steroid injections and surgical excision of the painful nerve. The available literature contains varied conclusions. Thomson et al, in a review of the current literature, cited that there is insufficient evidence with which to assess the effectiveness of surgical and non-surgical interventions for Morton's neuroma and that well designed trials are needed to begin to establish an evidence base for the treatment of Morton's neuroma pain (Thomson, 2001). Serial ethanol injection therapy has been reported to be an effective alternative to surgical excision (Fanucci, 2004). However, despite wide adoption of this treatment, no randomized, double blinded, placebo-controlled study exists to verify the efficacy of this treatment in comparison to longer standing similar therapies, such as corticosteroid injection.

The American College of Foot and Ankle Surgeons (ACFAS) addresses conservative and injection treatment of Morton's neuroma in their 2009 practice guideline: Diagnosis and treatment of forefoot disorders - Morton's intermetatarsal neuroma. Conservative care focuses on elimination of pressure and irritation of the nerve. Injection therapies for pain relief include local anesthetic blocks, corticosteroids and neurolytic alcohol injections. They caution that overuse of cortisone injections can result in atrophy of the plantar fat pad as well as joint subluxation.

A randomized, double-blind, placebo controlled clinical trial, Comparison of Corticosteroid and Ethanol Injection Therapy in the Treatment of Morton's Neuroma continues to recruit patients. In this trial, 120 patients will be randomized to three treatments, specifically lidocaine injection, corticosteroid injection, or ethanol injection. Outcomes will be assessed at 3, 6 and 12 month time points using validated questionnaires as well as a non-validated disease specific questionnaire. Primary endpoint will be graded change in the physical function portion of the Medical Outcomes Study short form (SF-36) (NCT00284583).

Peer Reviewed Publications:

1. Bennett GL, Graham CE, Mauldin DM. Morton's interdigital neuroma: a comprehensive treatment protocol. Foot Ankle Int. 1995; 16(12):760-763.
2. Dockery GL. The treatment of intermetatarsal neuromas with 4% alcohol sclerosing injections. J Foot Ankle Surg. 1999; 38(6):403-408.
3. Fanucci E, Masala S, Fabiano S, et al. Treatment of intermetatarsal Morton's neuroma with alcohol injection under US guide: 10-month follow-up. Eur Radiol. 2004; 14(3):514-518.  
4. Hassouna H, Singh D. Morton's metatarsalgia: pathogenesis, aetiology and current management. Acta Orthop Belg. 2005; 71(6):646-655.
5. Hassouna H, Singh D, Taylor H, Johnson S. Ultrasound guided steroid injection in the treatment of interdigital neuralgia. Acta Orthop Belg. 2007; 73(2):224-229.
6. Hughes RJ, Ali K, Jones H, Kendall S, Connell DA. Treatment of Morton's neuroma with alcohol injection under sonographic guidance: follow-up of 101 cases. Am J Roentgenol. 2007; 188(6):1535-1539.
7. Markovic M, Crichton K, Read JW, et al. Effectiveness of ultrasound-guided corticosteroid injection in the treatment of Morton's neuroma. Foot Ankle Int. 2008; 29(5):483-487.
8. Mozena JD, Clifford JT. Efficacy of chemical neurolysis for the treatment of interdigital nerve compression of the foot: a retrospective study. J Am Podiatr Med Assoc. 2007; 97(3):203-206.
9. Wu KK. Morton neuroma and metatarsalgia. Curr Opin Rheumatol.  2000; 12(2):131-142. 

Government Agency, Medical Society and Other Authoritative Publications:

1. American Academy of Orthopedic Surgeons. Morton's Neuroma. Available at:  http://orthoinfo.aaos.org/fact/thr_report.cfm?Thread_ID=233&topcategory=Foot. Accessed on October 4, 2009.
2. American College of Foot and Ankle Surgeons (ACFAS). Clinical Practice Guideline Forefoot Disorders Panel: Diagnosis and treatment of forefoot disorders. Section 3. Morton's intermetatarsal neuroma. J Foot Ankle Surg. 2009; 48(2):251-256.
3. Digiovanni C; Brown University. Comparison of alcohol and steroid injection for treating Morton's neuroma. NLM Identifier: NCT00284583. Last updated on January 30, 2006. Available at: http://www.clinicaltrials.gov/ct/show/NCT00284583 . Accessed on October 4, 2009.
4. Thomson CE, Gibson JNA, Martin D. Interventions for the treatment of Morton's neuroma. Cochrane Database of Systematic Reviews 2004, Issue 3. Art. No.: CD003118. DOI: 10.1002/14651858.CD003118.pub2.

Intermetatarsal Neuroma
Morton's Neuroma