Peripheral Nerve Blocks: A Color Atlas, 3rd Edition

66. Sphenopalatine Block

Miles Day

Rinoo Vasant Shah

Patient Position: Supine.

Indications: Pain syndromes involving the face and head including sphenopalatine neuralgia, sympathetically maintained pain, trigeminal neuralgia, migraine headaches, cluster headaches, atypical facial pain, cancer pain.

Needle Size: 21-gauge, 100-mm b-beveled needle or 20-gauge curved, blunt, 5-mm active tip, Racz-Finch Kit (RFK needle Radionics, Burlington, MA) is preferred; 16-gauge, 1.25-inch angiocatheter (introducer).

Medications: 1 to 2 mL of 2% lidocaine, 0.2% ropivacaine, 0.25% bupivacaine, or 0.25% levobupivacaine with or without 40 mg triamcinolone diacetate, 40 mg methylprednisolone, or 4 mg dexamethasone.

Anatomic Landmarks: The sphenopalatine ganglion lies in the pterygopalatine fossa adjacent to the middle turbinate.

Fluoroscopically Guided Technique: After sterile preparation of the region, the pterygopalatine fossa posterior to the posterior aspect of the maxillary sinus is visualized using a lateral view of the skull. When the ipsilateral and contralateral pterygopalatine fossae are superimposed upon one another, it should resemble a “vase.” The angiocatheter and RFK needle is introduced. An anteroposterior view is obtained, and the needle is introduced toward the middle turbinate. If resistance is encountered, the needle is redirected by turning the bevel. Once the needle touches the palatine bone adjacent to the middle turbinate, the needle advancement is stopped. The needle position in the fossa is confirmed with a lateral view. Next, sensory stimulation at 50 Hz and 0 to 1 V is performed. The stimulation of the sphenopalatine ganglion produces paresthesias at the root of the nose at 0.1 to 0.7 V. Once the appropriate stimulation is elicited, 1 mL of nonionic, water-soluble contrast is injected. This ensures that the needle is not intravascular or intranasal. Next, inject 1 to 2 mL of local anesthetic mixture. If the block is successful, a radiofrequency lesion can be performed at 80°C for 90 seconds. Two lesions are usually performed. Electromagnetic field-pulsed radiofrequency lesioning is performed at 42°C for 120 seconds 2 to 3 times.

Tips

1.   Evidence of a successful block includes pain relief, ipsilateral nasal congestion, and corneal injection.

2.   If paresthesias are felt in the teeth, the maxillary branch of the trigeminal nerve is being stimulated and the needle needs to be redirected caudally.

3.   Stimulation of the greater and lesser palatine nerves results in paresthesias of the hard palate and indicates that the needle needs to be redirected posteriorly and medially.

4.   Always perform sensory stimulation prior to the injection of the local anesthetic mixture.

5.   If the patient complains of pain during the radiofrequency lesioning, halt the lesioning and inject an additional 1 to 2 mL of local anesthetic. Wait 3 to 5 minutes and then resume lesioning.

6.   Radiofrequency lesioning on occasion has resulted in bradycardia. Cessation of the lesioning resulted in resolution of the bradycardia. If the bradycardia is not symptomatic, the lesioning can be continued. If symptomatic, small doses of atropine can be given to complete the lesioning.

7.   Complications include nosebleed, numbness of the upper teeth, hard palate, or pharynx; hematoma; and damage to the nerves or blood vessels.

Suggested Readings

Day MR, Racz GB. Sphenopalatine ganglion blockade. In: Waldman SD, ed. Interventional pain management, 2nd ed. Philadelphia: WB Saunders, 2001:307–311.

Konen A. Unexpected effects due to radiofrequency thermocoagulation of the sphenopalatine ganglion: two case reports. Pain Digest 2000;10:30–33.