Sphenopalatine Block

By admin On Jul 30, 2023

Ovid: Peripheral Nerve Blocks: A Color Atlas

Editors: Chelly, Jacques E.

Title: Peripheral Nerve Blocks: A Color Atlas, 3rd Edition

> Table of Contents > Section VII – Pain Blocks > 66 – Sphenopalatine Block

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.

P.441

Tips

Evidence of a successful block includes pain relief, ipsilateral nasal congestion, and corneal injection.
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.
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.
Always perform sensory stimulation prior to the injection of the local anesthetic mixture.
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.
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.
Complications include nosebleed, numbness
of the upper teeth, hard palate, or pharynx; hematoma; and damage to
the nerves or blood vessels.