What is involved in a sphenopalatine nerve block procedure?

From the Guidelines

A sphenopalatine nerve block procedure should be approached with caution, particularly in patients with suspected or confirmed COVID-19, as it may be considered an aerosol-generating procedure and increase the risk of transmission to healthcare workers 1. The procedure typically involves the application of local anesthetic to the sphenopalatine ganglion to treat various types of facial and head pain.

• The most common approach is transnasal, where a cotton-tipped applicator or catheter soaked in local anesthetic (usually 2% lidocaine or 0.5% bupivacaine) is inserted into the nostril and advanced along the superior border of the middle turbinate until it reaches the posterior nasopharynx where the sphenopalatine ganglion is located.
• Alternative approaches include transoral or lateral approaches guided by imaging.
• Patients may experience temporary numbness in the palate, posterior pharynx, or face, and minor side effects can include bitter taste, nasal irritation, or light-headedness.
• The procedure works by blocking pain signals from the sphenopalatine ganglion, which is a collection of nerve cells involved in facial sensation and autonomic functions.
• This nerve block is particularly effective for conditions like cluster headaches, migraines, trigeminal neuralgia, and certain facial pain syndromes. However, the current evidence does not strongly support the use of sphenopalatine ganglion block for the treatment of chronic migraine, and its effectiveness for this condition is still uncertain 1.
• In general, the decision to perform a sphenopalatine nerve block should be made on a case-by-case basis, taking into account the individual patient's condition, the potential benefits and risks of the procedure, and the availability of alternative treatments.

From the Research

Sphenopalatine Nerve Block Procedure

• The sphenopalatine nerve block is a procedure used to treat various facial pain syndromes, including cluster headaches, migraines, and trigeminal neuralgia 2.
• The procedure involves the injection of a local anesthetic, such as lidocaine or bupivacaine, into the sphenopalatine ganglion, which is a collection of neurons located in the face 3, 4.
• The injection can be performed using various techniques, including fluoroscopy-guided injection or intranasal administration using a device such as the SphenoCath or Tx360 3, 4.
• The procedure has been shown to be effective in reducing pain in patients with facial pain syndromes, with some studies demonstrating significant improvements in pain scores and quality of life 3, 2, 5.

Types of Sphenopalatine Nerve Blocks

• There are several types of sphenopalatine nerve blocks, including:
  • Diagnostic block: used to diagnose the source of pain and determine the effectiveness of the block 2.
  • Therapeutic block: used to treat pain and reduce inflammation 3, 4.
  • Neurolytic block: used to destroy the nerve fibers and provide long-term pain relief 5.
  • Radiofrequency ablation: used to heat the nerve fibers and provide long-term pain relief 2.

Potential Risks and Complications

• The sphenopalatine nerve block is generally considered a safe procedure, but there are potential risks and complications, including:
  • Bleeding or hematoma at the injection site 3.
  • Infection or abscess formation 3.
  • Nerve damage or numbness 6.
  • Cranial nerve palsy, as reported in a case study where a patient developed a cranial nerve III palsy after receiving an intranasal cocaine treatment for cluster headache 6.