How is a trigeminal ganglion block administered for pain management?

Updated: Jun 19, 2018
  • Author: Anthony H Wheeler, MD; Chief Editor: Meda Raghavendra (Raghu), MD  more...
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Answer

Trigeminal ganglion blockade should be performed only by skilled and experienced interventionists. Using the technique described by Brown, the patient is placed in a supine position. See the images below.

Anatomy and needle-insertion plane of trigeminal g Anatomy and needle-insertion plane of trigeminal ganglion block technique. See text for details.
Anatomy and technique of trigeminal ganglion block Anatomy and technique of trigeminal ganglion block. See text for details.

A 22-gauge, 10-cm needle is inserted through a skin wheal approximately 3 cm lateral to the corner of the mouth and medial to the masseter muscle in a direction that bisects the plane formed by the midpoint of the pupil with the patient staring at the ceiling. This allows the needle tip to contact the infratemporal surface of the greater wing of the sphenoid bone, immediately anterior to the foramen ovale at a depth of 4.5-6 cm.

Once the needle is positioned firmly against this bony target, it is withdrawn and redirected in a stepwise manner until it enters the foramen ovale at a depth of about 6-7 cm, approximately 1.5 cm beyond the initial needle length required to contact the bone. As the foramen is entered, paresthesia in the mandibular distribution usually is evoked. Further slight and careful movement of the needle may elicit paresthesia in the distributions of the ophthalmic and maxillary nerves. These additional paresthesiae verify a periganglionic placement of the needle tip.

Aspiration should be performed first to check for CSF because the posterior two thirds of the trigeminal ganglion is enveloped in the reflection of the dura. One milliliter of a short-acting LA then can be injected. If neural blockade is incomplete after 5-10 minutes, an additional 1-2 mL of LA can be injected or the needle can be repositioned to obtain a more complete block. The most concerning complication with this procedure is subarachnoid injection. Moreover, because the needle passes through a highly vascular region, hematoma formation is a possibility.


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