Is an intercostal nerve block with steroid contraindicated for postherpetic neuralgia?

Intercostal Nerve Block with Steroid for Postherpetic Neuralgia

Intercostal nerve blocks with steroids are not contraindicated for postherpetic neuralgia and may be considered as an interventional option after first-line therapies have failed. While not first-line therapy, they represent a reasonable intervention for patients with inadequate response to conventional treatments.

First-Line Treatment Options for PHN

Current guidelines recommend a stepwise approach to treating postherpetic neuralgia:

1. First-line pharmacological treatments:

   • Gabapentin (FDA-approved for PHN) - titrate to 2400 mg/day in divided doses 1
   • Pregabalin (FDA-approved for PHN) 1
   • Tricyclic antidepressants (NNT = 2.64) 1
   • Topical lidocaine patches (NNT = 2) 1
   • Topical capsaicin patches or cream (NNT = 3.26) 1

2. Second-line treatments:

   • SNRIs (duloxetine) 1
   • Tramadol 1

Role of Interventional Procedures

When patients have inadequate response to first-line therapies, interventional approaches including nerve blocks may be considered:

• Intercostal nerve blocks have shown efficacy in pain management, with evidence supporting their use in thoracic pain conditions 1
• Adding dexamethasone to local anesthetic for intercostal nerve blocks has been shown to prolong the duration of analgesia 1
• A 2019 systematic review of interventional treatments for PHN included intercostal nerve blocks with triamcinolone (steroid) as one of the recommended interventional options 2

Evidence for Steroid Use in Nerve Blocks for PHN

While systemic corticosteroids have not shown benefit in preventing PHN (very low-certainty evidence) 3, 4, targeted delivery via nerve blocks may provide benefit:

• Intrathecal methylprednisolone with lidocaine has shown efficacy for PHN with a low NNT of 1.13 1
• Recent research (2024) shows that ultrasound-guided intercostal nerve blocks may be effective for acute herpes zoster and prevention of PHN 5
• Paravertebral blocks and repeated/continuous epidural blocks have shown efficacy in reducing PHN incidence 6

Recommended Approach for PHN Management

1. Start with first-line therapies:

   • Anticonvulsants (gabapentin or pregabalin)
   • Topical treatments (lidocaine patches, capsaicin)
   • Tricyclic antidepressants (if no contraindications)

2. If inadequate response after 4-8 weeks:

   • Consider interventional approaches including intercostal nerve blocks
   • When performing intercostal nerve blocks, adding steroid (such as dexamethasone or triamcinolone) to local anesthetic can prolong analgesic effect 1

3. For refractory cases:

   • Consider more advanced interventions such as spinal cord stimulation
   • Multidisciplinary pain management approach

Important Considerations and Caveats

• Patient selection: Ensure proper diagnosis of PHN before proceeding with interventional treatments
• Timing: Interventional approaches are generally considered after failure of first-line pharmacological therapies
• Technique: Ultrasound guidance improves safety and efficacy of intercostal nerve blocks 5
• Monitoring: Watch for potential adverse effects including pneumothorax, local anesthetic toxicity, and steroid-related complications
• Expectations: Discuss with patients that nerve blocks may provide temporary relief and might need to be repeated

In conclusion, intercostal nerve blocks with steroids are not contraindicated for postherpetic neuralgia and represent a reasonable interventional option for patients who have failed first-line therapies, with evidence supporting their efficacy and safety when properly performed.