Efficacy of rTMS in PHN Patients with Depression Undergoing Neuromodulation

Overview

This randomized, double-blind, placebo-controlled trial protocol investigates the efficacy and safety of 10 Hz repetitive transcranial magnetic stimulation (rTMS) as an adjunct to interventional neuromodulation in patients with postherpetic neuralgia (PHN) and mild to moderate depression. The study aims to assess whether rTMS can reduce poor prognosis incidence and improve pain and mood outcomes over 3 to 6 months post-discharge.

Background

Postherpetic neuralgia is a common complication of herpes zoster that significantly impairs quality of life and is often complicated by depression, which worsens prognosis. Interventional neuromodulation therapies like pulsed radiofrequency and spinal cord stimulation provide pain relief but up to one-third of patients still experience poor outcomes. Repetitive transcranial magnetic stimulation (rTMS) targeting the primary motor cortex has shown promise in modulating neuropathic pain and depressive symptoms. This study explores the potential of rTMS to improve outcomes when combined with standard interventional treatments in PHN patients with comorbid depression.

Data Highlights

The trial will enroll 174 adult PHN patients randomized equally to receive either 10 Hz rTMS or sham stimulation for five consecutive days alongside interventional neuromodulation. Primary outcome is the incidence of poor prognosis at 3 months post-discharge. Secondary outcomes include poor prognosis at 6 months, Visual Analog Scale (VAS) sleep scores, short-form McGill Pain Questionnaire (SF-MPQ) scores, Self-Rating Depression Scale (SDS) scores, patient satisfaction, Pain Disability Index (PDI) scores, Multidimensional Fatigue Inventory-20 (MFI-20) scores, pregabalin dosage, and need for tramadol or antidepressants. Safety assessments will monitor adverse events such as headache, neck pain, insomnia, dizziness, and tachycardia.

Key Findings

• PHN frequently coexists with depression, creating a vicious cycle that worsens pain and treatment outcomes.
• Interventional neuromodulation therapies provide pain relief but up to 32.6% of patients still experience poor prognosis.
• High-frequency (10 Hz) rTMS targeting the primary motor cortex modulates pain pathways and has demonstrated efficacy in neuropathic pain and depression.
• This study will evaluate rTMS as an adjunct to interventional neuromodulation to reduce poor prognosis incidence and improve pain, mood, and functional outcomes.
• Safety outcomes will be carefully monitored to assess tolerability of rTMS in this patient population.

Clinical Implications

If effective, 10 Hz rTMS could be incorporated as a non-invasive adjunct therapy to enhance pain relief and mood improvement in PHN patients undergoing interventional neuromodulation. Addressing both neuropathic pain and comorbid depression concurrently may reduce poor prognosis rates and improve overall patient quality of life. Clinicians should consider the potential benefits of integrating neuromodulatory techniques like rTMS in comprehensive PHN management.

Conclusion

This trial protocol outlines a rigorous approach to evaluating the adjunctive use of rTMS in PHN patients with depression receiving interventional neuromodulation. The results will provide preliminary evidence on its efficacy and safety, potentially informing future therapeutic strategies.

References

1. Study Protocol ChiCTR2500096978 -- Impact of rTMS on PHN with Depression