From the Guidelines
A 20mm Morton's neuroma is considered large and typically requires surgical excision due to its size, as conservative treatments are less likely to be effective long-term 1.
Diagnosis and Treatment
The diagnosis of Morton's neuroma can be confirmed using MRI, which has a sensitivity of 87%, specificity of 100%, accuracy of 89%, PPV of 100%, and NPV of 60% in surgically treated patients 1. Treatment should begin with conservative measures, including:
- Wearing wide-toe box shoes
- Avoiding high heels
- Using metatarsal pads
- Taking NSAIDs like ibuprofen (400-600mg three times daily) for pain relief If these fail to provide adequate relief, corticosteroid injections (typically methylprednisolone 40mg mixed with lidocaine) directly into the affected interdigital space may help reduce inflammation and pain.
Surgical Excision
For a neuroma of this size, however, surgical excision is often necessary as conservative treatments are less likely to be effective long-term. The procedure involves removing the enlarged nerve tissue through a dorsal incision between the metatarsal heads. Recovery typically takes 2-6 weeks, with full healing in 3 months. This size of neuroma represents significant nerve enlargement caused by chronic compression and irritation between metatarsal heads, usually between the third and fourth toes, resulting in fibrosis and perineural thickening.
Post-Treatment Expectations
Patients should be aware that even after treatment, some residual numbness in the affected toes is expected due to the nature of the condition. Note that the evidence from 1 is not directly relevant to the treatment of Morton's neuroma, as it pertains to the endoscopic removal of colorectal lesions. Therefore, it is not considered in the treatment recommendations for Morton's neuroma.
From the Research
Overview of Morton's Neuroma
- Morton's neuroma is a condition that affects the nerves in the foot, causing pain and discomfort.
- The treatment options for Morton's neuroma include operative, conservative, and infiltrative methods 2.
Treatment Options for 20mm Morton's Neuroma
- Operative treatment has shown better outcomes for Morton's neuroma, with case series and randomized controlled trials (RCTs) demonstrating better results with invasive treatment 2.
- Corticosteroid injection is a common non-surgical treatment for Morton's neuroma, with studies showing significant reduction in pain and improvement in function 3, 4.
- However, the effectiveness of corticosteroid injection can vary, with some studies showing no significant difference in pain and function improvement compared to placebo 5.
Outcomes of Corticosteroid Injections for Morton's Neuroma
- Corticosteroid injections can provide satisfactory outcomes for Morton's neuroma, with maximal pain reduction between 1 week and 3 months after injection 4.
- However, almost 30% of patients may eventually undergo operative treatment due to persistent pain 4.
- The medium-term results of corticosteroid injections for Morton's neuroma show that the injection remains effective in over a third of cases for up to almost 5 years 6.
Non-Surgical Treatment Modalities for Morton's Neuroma
- Other non-surgical treatment modalities for Morton's neuroma include alcohol injection, extra-corporeal shockwave therapy (ESWT), radiofrequency ablation (RFA), cryoablation, capsaicin injection, botulinum toxin, orthosis, and YAG laser therapy 3.
- These treatment modalities have shown statistically significant improvements in pain and function, but with limitations to their application 3.