How is a mandibular nerve 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

Answer

The anterior division of the mandibular nerve is principally motor and supplies the muscles of mastication, whereas the posterior division is principally sensory and supplies the skin and mucous membranes overlying the jaw and skin anteriorly and superior to the ear.

The Brown technique for performing this block begins with the patient in supine position with the head and neck turned away from the side to be blocked. See the image below.

Anatomy of mandibular block and needle insertion t Anatomy of mandibular block and needle insertion technique. See text for details.

The patient is asked to open and close the mouth gently so that the operator can identify and palpate the mandibular notch. A 22-gauge, 8-cm needle is inserted in the midpoint of the mandibular notch and directed at a slightly cephalad and medial angle through the notch to the lateral pterygoid plate at a depth of approximately 5 cm. The needle is then withdrawn to a subcutaneous position and carefully walked off the posterior border of the pterygoid plate in a horizontal plane. The needle should not be advanced more than 0.5 cm past the depth of the pterygoid plate because the superior constrictor muscle of the pharynx can be pierced easily. When the needle is in appropriate position, 5 mL of LA can be administered. Complications include hematoma formation and subarachnoid injection.

Distal trigeminal blocks can be performed to target specific distal branches of the 3 divisions of the trigeminal nerve, specifically the supraorbital branch of the ophthalmic nerve, infraorbital branch of the maxillary nerve, and mental branch of the mandibular nerve. These blocks are performed with a 25-gauge needle directed at the superficial foraminal site, where approximately 2-3 mL of LA can then be injected. See the image below.

Distal trigeminal block technique. See text for de Distal trigeminal block technique. See text for details.

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