SPG Block

Summary:
SPG (sphenopalatine ganglion) block involves delivering local anesthetic intranasally to a nerve cluster involved in facial pain and autonomic features of migraine.

Biological Plausibility

The SPG connects to the trigeminal system and parasympathetic outflow, both active during migraine. Blocking this structure may reduce pain transmission and autonomic symptoms.

Evidence

Small RCTs and open-label studies show reduced migraine intensity and duration with SPG blocks. Effects may be transient and require repeated treatments.

Effect Size

Acute pain relief in up to 50% of patients within 15–30 minutes. Preventive effect inconsistent.

⚠️ Risk

Low. Some patients report nasal irritation, numbness, or bitter taste. Rare epistaxis. Professional training required.

Cost

$$$

Scores

  • Benefit: 2
  • Burden: 4
  • Ratio: 0.5

Clinical Takeaways

  • Best suited for acute treatment or high-frequency migraine with autonomic symptoms.
  • Requires access to trained provider and specialized applicator.
  • Preventive role remains uncertain.

Key References

  • Binfalah M, et al. *Sphenopalatine ganglion block for acute migraine: a randomized, double-blind study.* Pain Res Treat. 2015.
  • Cady R, et al. *Sphenopalatine ganglion block in headache disorders: an overview.* Curr Pain Headache Rep. 2015.
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