When injecting Kenalog (triamcinolone) for a Morton's neuroma, is it best to inject beside or into the neuroma?

Injection Technique for Morton's Neuroma with Kenalog (Triamcinolone)

When injecting Kenalog (triamcinolone) for Morton's neuroma, it is best to inject beside the neuroma rather than directly into it for optimal effectiveness and reduced risk of complications.

Rationale for Injection Placement

• Intralesional corticosteroid injections are commonly used for treating Morton's neuroma, with triamcinolone acetonide (Kenalog) being one of the preferred agents 1
• The preferred technique involves injecting just beneath the dermis in the upper subcutis adjacent to the neuroma, not directly into the neuroma itself 1
• This technique allows for better diffusion of the medication around the neuroma while minimizing potential damage to the nerve structure 1, 2

Evidence Supporting Perilesional Injection

• Studies show that injecting corticosteroid around the neuroma rather than directly into it results in better long-term pain relief and reduced risk of complications 2
• Ultrasound-guided injections, which allow precise placement of medication beside the neuroma, demonstrate significantly better outcomes at 45 days, 2 months, and 3 months compared to blind injections 2
• Perilesional injection technique minimizes the risk of mechanical trauma to the nerve structure that could exacerbate symptoms 3

Technical Considerations

• The recommended approach is to inject 0.05-0.1 mL of triamcinolone acetonide (5-10 mg/mL) beside the neuroma 1
• Multiple small injections around the neuroma are preferable to a single large injection directly into it 1
• Ultrasound guidance significantly improves injection accuracy and outcomes compared to blind techniques 3, 2
• When using ultrasound guidance, the needle should be visualized approaching the neuroma but stopping short of direct penetration 2

Potential Complications

• Direct injection into the neuroma may cause:
  • Increased mechanical trauma to the nerve 3
  • Higher risk of fat and dermal atrophy 1
  • Potential for increased pain during injection 2
• Perilesional injection reduces these risks while maintaining therapeutic efficacy 2

Treatment Outcomes

• Corticosteroid injections placed beside the neuroma can provide significant pain relief for Morton's neuroma patients 1, 2
• Ultrasound-guided perilesional injections show superior outcomes with over 60% of patients experiencing short-term pain relief 2
• A cost-effectiveness analysis shows that ultrasound-guided injection therapies are indicated as first-line treatment for symptomatic Morton's neuromas when conservative management fails 4

Practical Application

• Use ultrasound guidance whenever possible to ensure accurate placement beside the neuroma 3, 2
• Inject small volumes (0.05-0.1 mL) of triamcinolone acetonide at multiple points around the neuroma 1
• Consider a combination of local anesthetic (e.g., 1 mL of 2% mepivacaine) with triamcinolone (40 mg) for immediate and sustained relief 2
• Monitor for potential side effects including fat atrophy, skin changes, and temporary pain at injection site 1