Maxillary Nerve Block Technique

Updated: Jul 05, 2016
  • Author: Anusha Cherian, MBBS, MD, DNB; Chief Editor: Meda Raghavendra (Raghu), MD  more...
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Technique

Techniques for Maxillary Nerve Block

The following 3 techniques may be used to perform a maxillary nerve block:

  • High tuberosity approach
  • Greater palatine canal approach
  • Coronoid approach

High tuberosity approach

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).

High tuberosity approach to blocking maxillary ner High tuberosity approach to blocking maxillary nerve.

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.

Greater palatine canal approach

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.

Greater palatine canal approach for maxillary nerv Greater palatine canal approach for maxillary nerve block.

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.

Coronoid approach

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:

  • Pulpal area of all teeth
  • Buccal periosteum and bone
  • Soft tissue and bone of the palate
  • Skin of the lower eyelid, side of nose, cheek, and upper lip
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Complications

Complications related to the local anesthetic include the following:

  • Toxicity: If a large volume of local anesthetic is administered or an inadvertent intravascular injection has taken place, the systemic toxicity characteristic of the drug used may develop; symptoms may be minimal to moderate (eg, anxiety, numbness, dizziness, weakness, and tremors) but are sometimes severe (eg, central nervous system or cardiovascular collapse).
  • Allergic reaction: This may occur in response to the preservatives added to the local anesthetic (eg, methylparaben or sodium metabisulfite) or to an ester-group local anesthetic.

Complications related to the technique itself include the following:

  • Persistent paresthesia and numbness: These may be due to maxillary nerve trauma or to local hematoma formation.
  • Infection: Needle track infection is possible.
  • Blockade of nerves in the vicinity of the maxillary nerve block: This may involve facial nerve block (typically transient), retrobulbar nerve block (rare), optic nerve block (rare but capable of inducing temporary blindness), or sixth nerve block (capable of causing diplopia).
  • Retrobulbar hematoma formation
  • Edema and sloughing of tissues (very rare)
  • Penetration of nasal cavity
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