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Brown: Atlas of Regional Anesthesia, 3rd ed., Copyright © 2006 Saunders, An Imprint of Elsevier
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PLACEMENT

Anatomy.

The maxillary nerve is entirely sensory and passes through the foramen rotundum to exit from the cranium. The nerve passes through the pterygopalatine fossa, medial to the lateral pterygoid plate, on its way to the infraorbital fissure. As illustrated in Figure 21-2 , it is accessible to the anesthesiologist via a lateral approach as it passes into the pterygopalatine fossa.

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Figure 21-2  Maxillary block anatomy: peripterygoid relations.


Position.

The patient is placed in the supine position with the head and neck rotated away from the side to be blocked. While the anesthesiologist palpates the mandibular notch, the patient is asked to open and close the mouth gently to make the notch even more obvious.

Needle Puncture.

A 22-gauge, 8-cm needle is inserted through the mandibular notch in a slightly cephalomedial direction, as illustrated in Figure 21-3 . This allows the needle to impinge on the lateral pterygoid plate at a depth of approximately 5 cm (needle position 1). The needle is then withdrawn and redirected in a stepwise manner toward position 2 (the pterygopalatine fossa). The needle should not be advanced more than 1 cm past the depth of initial contact with the pterygoid plate. As the needle is walked off the pterygoid plate, a “sense” of walking into the pterygopalatine fossa should be appreciated. Once the needle is adequately positioned, 5 mL of local anesthetic is injected.

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Figure 21-3  Maxillary block anatomy: needle insertion technique.


Potential Problems.

Owing to the close proximity of the maxillary nerve to the infraorbital fissure, some spill of local anesthetic into the orbit is possible; thus, patients should be warned that movement of the eye and/or vision might be affected. The lateral approach to the maxillary nerve also involves insertion of the needle through a vascular region, and hematoma formation is possible. Again, owing to the close association of the pterygopalatine fossa with the orbit, patients frequently develop a “black eye” after this block.

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