How is a sphenopalatine ganglion block performed in an adult patient without anesthetic allergy, active nasal infection, or coagulopathy?

Sphenopalatine Ganglion Block Technique

The sphenopalatine ganglion block can be performed using either a transnasal topical approach (simplest but less predictable) or a transnasal injection technique (more reliable and durable), with the injection method being superior when sustained pain relief is needed. 1, 2

Transnasal Topical Approach (Simplest Method)

This is the most common technique but has limitations in predictability and duration 1:

• Apply topical local anesthetic (typically 4% lidocaine) to the nasal mucosa between the middle and inferior turbinates, extending from the nares to the nasopharynx 1
• Position cotton-tipped applicators soaked in local anesthetic along the posterior aspect of the middle turbinate, aiming toward the sphenopalatine foramen 2
• Leave applicators in place for 10-15 minutes to allow diffusion 2

Critical Limitation of Topical Approach

The distance from the nasal mucosa covering the sphenopalatine foramen to the actual ganglion averages 6.77 mm (range 4.00-11.60 mm), making passive diffusion of topical anesthetic unreliable. 3 This anatomical reality explains why topical approaches provide unpredictable and short-duration blockade 1.

Transnasal Injection Technique (More Reliable)

This method provides predictable and durable blockade while maintaining technical simplicity 1:

Step-by-Step Procedure

1. Perform topical anesthesia first to the nasal mucosa between the middle and inferior turbinates from nares to nasopharynx 1

2. Insert a needle through the same anesthetized tract using a tailored plastic cover-sheath to guide needle placement 1

3. Advance the needle until the tip reaches near the medial pterygoid plate at the level of the middle concha 1

4. Inject blocking agent (mixture of local anesthetics such as lidocaine 4% and ropivacaine 0.5%, typically 1 ml per side) 4

5. Fluoroscopic confirmation (optional after initial learning): contrast should flow superoposteriorly to the maxilla without vascular uptake 1

Expected Duration

• Topical technique: approximately 1 day of relief 1
• Injection technique: approximately 4 weeks of relief 1

Endoscopic Approach (Alternative for Chronic Conditions)

For patients with chronic cluster headache resistant to pharmacologic therapy 2:

• Access the pterygopalatine fossa endoscopically through the lateral nasal wall 2
• Inject a mixture of local anesthetics and corticosteroids under direct visualization 2
• This approach is minimally invasive and should be attempted before more invasive surgical procedures 2

Important Caveats and Pitfalls

The efficacy of sphenopalatine ganglion block for postdural puncture headache remains controversial. A high-quality randomized trial found no statistically significant difference between local anesthetic and saline placebo at 30 minutes (median pain reduction similar in both groups), suggesting a substantial placebo effect 4. However, 50% of patients in both groups avoided epidural blood patch 4.

There is insufficient evidence to recommend for or against sphenopalatine ganglion block for chronic migraine treatment according to VA/DoD guidelines 5.

Common Pitfalls to Avoid

• Assuming topical application reaches the ganglion: The anatomical distance of nearly 7 mm makes passive diffusion unlikely 3
• Expecting immediate, definitive results: Even with injection techniques, response may be variable 4
• Using as first-line for postdural puncture headache: Consider conservative management first; epidural blood patch remains the gold standard when intervention is needed 6, 4