The following 3 techniques may be used to perform a maxillary nerve block:
The high tuberosity approach blocks the nerve as it courses along the pterygopalatine fossa. It anesthetizes the hemimaxilla on the side of the block, including the maxillary teeth; the buccal, gingival, and periodontal tissues; and the soft and hard palate.
With the mouth open and a tongue depressor drawing the cheek outward, the highest point on the mucobuccal fold just distal to the second maxillary molar teeth is identified. This area is cleaned. A needle is inserted at this point at a 45° angle and directed posteriorly, superiorly, and medially toward the bone (see the image below).
The needle is then advanced 3 cm so that it lies within the fossa. Negative aspiration for blood is confirmed in this plane, and, after the needle is rotated by a quadrant, 1.8 mL of local anesthetic is slowly injected here. This technique is associated with a 95% success rate of nerve block. However, injury of the maxillary artery by the needle tip may result in rapid hemorrhage.
The greater palatine canal approach blocks the maxillary nerve as it travels through the pterygopalatine fossa. This is the most frequently used approach and is associated with a higher rate of success; however, it is contraindicated if the canal cannot be located or negotiated.
The greater palatine foramen is usually located on the palate, 1 cm medial and adjacent to the second molar teeth. A cotton swab may be pressed on the palate to find the depression caused by the foramen.
A greater palatine nerve block is performed with the patient in a semifallourous position. A 25-gauge long needle 1-2 mm is inserted in front of the greater palatine foramen (see the image below). The needle is inserted perpendicularly until the bone is contacted, and 0.5 mL of local anesthetic may be deposited here. Alternatively, 0.5 mL of local anesthetic may be deposited around the greater palatine foramen.
After a 3- to 5-minute wait, and with adequate palatal anesthesia ensured, the greater palatine foramen is probed for and walked in with the tip of a needle. Applying constant pressure to this area reduces the discomfort. The needle is advanced 3 cm. If no resistance is met with, 1.8 mL of local anesthetic is slowly injected after it is confirmed that no blood is aspirated in 2 planes. If resistance is encountered, the needle is redirected and reinserted at a different angle. If resistance is encountered earlier on or the canal cannot be negotiated, this approach is abandoned.
The coronoid approach is better performed under imaging guidance. It differs from the other 2 approaches in that its access is external.
The coronoid notch of the mandible is identified by having the patient open and close the mouth and palpating in front of and below the tragus. This area is cleaned with povidone-iodine and prepared.
With the mouth in neutral position, a 22-gauge long needle is advanced perpendicular to the skin at the center of the coronoid notch below the zygomatic arch. At a depth of 4-5 cm, the lateral pterygoid plate is encountered.
The needle is then withdrawn slightly, redirected anteriorly and superiorly, and advanced to a depth of 1 cm. At this point, paresthesias in the region of the maxillary nerve are usually elicited, and after negative aspiration, about 5-10 mL of the drug is slowly deposited here. If the needle is withdrawn by 2 mm, the block will include the mandibular nerve as well.
The following areas are anesthetized on the side of the block:
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