What are the data to support the use of occipital nerve stimulators (ONS) for treating chronic migraine or cluster headaches?

Occipital Nerve Stimulation for Chronic Headache Disorders

There is insufficient evidence to recommend occipital nerve stimulation (ONS) for the treatment and/or prevention of migraine or cluster headache. 1

Current Evidence Status

According to the 2023 VA/DoD Clinical Practice Guideline for the Management of Headache, there is insufficient evidence to recommend for or against any form of neuromodulation, including occipital nerve stimulation, for the treatment and/or prevention of migraine 1. The guideline specifically states that the evidence is neither for nor against various neuromodulation techniques, including external combined occipital and trigeminal neurostimulation systems.

Specific Recommendations for Headache Types:

1. For Cluster Headache:

   • The guideline suggests against an implantable sphenopalatine ganglion stimulator for the treatment of cluster headache (weak against recommendation) 1
   • Noninvasive vagus nerve stimulation is suggested for short-term treatment of episodic cluster headache (weak for recommendation) 1
   • No specific recommendation for occipital nerve stimulation

2. For Migraine:

   • Greater occipital nerve block is suggested for short-term treatment (weak for recommendation) 1
   • Insufficient evidence for greater occipital nerve block for prevention of chronic migraine 1
   • No specific positive recommendation for occipital nerve stimulation

Research Evidence on ONS

Despite the guideline's neutral stance, some research studies have shown potential benefits:

1. Long-term Outcomes:

   • A 2023 narrative review found that 56% of patients with specific headache types showed sustained responses to ONS over long-term follow-up (≥24 months) 2
   • For cluster headache specifically, 64% were long-term responders with only 19% experiencing loss of efficacy 2

2. Chronic Migraine:

   • A long-term prospective study with 9.4 ± 6.1 years follow-up showed substantial pain reduction in most patients with refractory chronic migraine, with VAS scores decreasing by 4.9 ± 2.0 points 3
   • Five of 35 permanently implanted patients became completely free from migraine attacks 3

3. Chronic Cluster Headache:

   • A study with 6.1 years median follow-up (range 1.6-10.7) found that 66.7% of chronic drug-resistant cluster headache patients were responders (≥50% reduction in daily attacks) 4
   • 40% showed stable condition with only sporadic attacks 4

Safety Concerns and Adverse Events

The high rate of adverse events is a significant concern with ONS:

• 71% of patients across studies experienced adverse events 2
• Most common complications include:
  • Lead migration (20%) 4
  • Battery depletion (70%) 4
  • Infection
  • Allergic reactions to surgical materials
  • Intolerable paresthesias 2

Clinical Approach

Given the current evidence:

1. First-line approaches should focus on established treatments with stronger evidence:

   • For cluster headache: subcutaneous sumatriptan, intranasal zolmitriptan, or normobaric oxygen therapy for acute treatment 1
   • For migraine: preventive medications (CGRP antagonists, anti-epileptics, beta-blockers) and acute treatments (triptans, NSAIDs) 1

2. Consider ONS only when:

   • Patient has failed all standard pharmacological treatments
   • Patient has failed less invasive neuromodulation approaches
   • Patient has demonstrated positive response to diagnostic occipital nerve blocks (>50% relief) 5
   • Patient has undergone psychological evaluation 3

Important Caveats

1. Most studies on ONS are open-label and uncontrolled, limiting the strength of evidence
2. The high rate of adverse events requires careful patient selection and thorough informed consent
3. The cost-effectiveness of ONS has not been well established
4. Many devices used for ONS are being used off-label (designed for spinal cord stimulation) 2

While some research shows promising results for ONS in specific headache disorders, particularly for drug-resistant chronic cluster headache and refractory chronic migraine, the current clinical practice guidelines do not support its routine use due to insufficient evidence.