What is the best course of treatment for a patient with thoracic back pain radiating to the abdomen, worsened by activities such as mopping and extending the right arm, who has responded well to lidocaine (lidocaine) patch and exercise program?

Management of Thoracic Back Pain Radiating to Abdomen

The lidocaine patch 5% is recommended as first-line therapy for thoracic back pain radiating to the abdomen, particularly when the patient has already demonstrated a positive response to this treatment and has pain exacerbated by specific movements like mopping and extending the right arm. 1

Assessment and Diagnosis

This presentation suggests thoracic radiculopathy or myofascial pain syndrome with the following characteristics:

• Pain radiation pattern from thoracic spine to abdomen
• Pain worsened by specific movements (mopping, extending right arm)
• Positive response to lidocaine patch
• No urinary symptoms (ruling out certain spinal pathologies)

Treatment Approach

First-Line Therapy

1. Lidocaine Patch 5%

   • Apply directly over the most painful thoracic area
   • Can be worn for up to 12-24 hours
   • Allow a patch-free period of at least 12 hours between applications
   • Up to 3 patches may be used simultaneously on different painful areas 1
   • Continue for at least 4 weeks to properly assess efficacy 1
   • Minimal systemic absorption with topical application makes this a safe option 1, 2

2. Exercise Program

   • Continue the current exercise program that has shown benefit
   • Focus on exercises that improve thoracic mobility and core strength
   • Avoid exercises that exacerbate pain (like those involving extended right arm)

Second-Line Options (if inadequate response after 4 weeks)

1. Topical NSAIDs

   • Consider diclofenac 1% gel applied to the painful area 3-4 times daily 3
   • Particularly useful for musculoskeletal component of pain 3

2. Oral NSAIDs

   • Use with caution, particularly in older persons
   • Should be used at the lowest effective dosage and shortest duration needed 3
   • Consider gastrointestinal protection if needed

3. Trigger Point Injections

   • Consider if specific trigger points can be identified
   • May provide significant relief for myofascial pain 3
   • Studies show that dry needling can be as effective as injections with medications 3

Third-Line Options

1. Duloxetine

   • Particularly if pain persists despite above measures
   • Has demonstrated effectiveness for chronic back pain 3

2. Topical Compounded Formulations

   • Consider compounded formulations containing amitriptyline-ketamine with additions of clonidine, gabapentin, or lidocaine 3
   • May be helpful when single-agent topicals provide insufficient relief

Monitoring and Follow-up

• Reassess pain levels and functional improvement after 4 weeks of lidocaine patch therapy
• Monitor for skin reactions at application sites (most common adverse effect) 2
• Evaluate progress with the exercise program and modify as needed

Special Considerations

• Avoid ice and water immersion of extremities or limit to 10 minutes at a time, no more than 4 times daily 3
• Maintain as normal a lifestyle as possible while managing pain 3
• If pain persists despite comprehensive management, consider referral to a pain specialist for further evaluation

Evidence Summary

The lidocaine patch 5% has demonstrated effectiveness for various pain syndromes including chronic back pain 4, 5. Case studies have shown that lidocaine patches can help relieve various pain characteristics including general pain, shooting pain, burning pain, and allodynia in patients with chronic low back pain 4. The safety profile is excellent with minimal systemic absorption and primarily limited to mild local skin reactions 2.

The combination of lidocaine patch therapy with an appropriate exercise program represents an evidence-based approach that minimizes risks while addressing both the nociceptive and potential neuropathic components of thoracic back pain radiating to the abdomen.