Maxillary Nerve Block 

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

Overview

Background

Complete maxillary nerve block is not commonly required (see Indications below).[1, 2, 3, 4] This is because the wide area of anesthesia resulting from maxillary nerve block (including the dural, temporal, and zygomatic regions; the mucosa of the maxillary sinus; and the maxillary teeth and their soft tissues) is often not needed. Frequently, the area to be blocked is very small (eg, a single tooth), and the appropriate local anesthesia can be achieved by more specific nerve blocks, which also have the advantage of causing less discomfort to the patient.

Indications

The indications for complete maxillary nerve block are few and include the following:

  • Procedures requiring anesthesia of multiple teeth and surrounding areas: Individual blocks are cumbersome and lead to patient discomfort; multiple blocks may necessitate administering a larger dose of the anesthetic, which may exceed the toxic dose.

  • Large canine abscesses: If specific nerve blocks are given, large volumes of local anesthetic may have to be administered; a maxillary nerve block can be performed with a relatively low dose of the drug.

  • Failure of local blocks as a result of infection or abscess formation: This may necessitate a maxillary nerve block, which is administered far from the site of infection.

  • Surgery on the maxilla, either alone or as a complement to general anesthesia

  • Postoperative pain relief after maxillary surgical procedures

  • Painful conditions in the maxillary area that do not respond to systemic analgesics

  • Some cases of trigeminal neuralgia

Contraindications

Contraindications for maxillary nerve block include the following:

  • Infection over the point of injection

  • Patients with coagulopathic abnormalities or those who are taking drugs that alter hemostasis

  • Patients who refuse the procedure

  • Patients with known allergy to local anesthetics

Technical Considerations

The maxillary nerve arises in the middle cranial fossa as a purely sensory division of the trigeminal ganglion (see the image below). It gives off a branch as it travels forward on the lateral wall of the cavernous sinus.

Branches of maxillary nerve. Branches of maxillary nerve.

After leaving the cranium via the foramen rotundum on the greater wing of the sphenoid, the nerve enters the pterygopalatine fossa, which is located posteroinferior to the orbit. Here, it gives off several sensory branches before exiting via the infraorbital fissure and then the infraorbital canal as the infraorbital nerve.

The nerve finally emerges from the infraorbital foramen on the maxillary bone along with the infraorbital artery and vein.

The branches of the maxillary nerve can be divided into the following 4 categories:

  • Intracranial branch

  • Branches in the pterygopalatine fossa

  • Branches in the infraorbital canal

  • Branches in the face

The intracranial branch of the maxillary nerve is the middle meningeal nerve, which innervates the dura mater.

The first of the branches in the pterygopalatine fossa to be considered is the pterygopalatine nerve, which contains the postganglionic parasympathetic secretomotor nerve fibers to the lacrimal gland. This nerve serves as a communication between the pterygopalatine ganglion and the maxillary nerve. It gives sensory innervation to the orbit, nose, palate, and pharynx via the following branches:

  • Nasopalatine nerve, which provides sensory supply to the premaxillary palatal mucosa

  • Greater and lesser palatine nerves, which supply the hard and soft palate

  • Orbital branches, which supply the periosteum of the orbit

  • Pharyngeal branches, which supply the mucosa of the nasopharyngeal wall

  • Nasal branches, which supply the mucosa of the posterior nasal septum, the superior and middle nasal conchae, and the superior ethmoid sinus

The other branches in the pterygopalatine fossa include the zygomatic nerve, which provides sensory supply to the skin over the forehead and cheek via its zygomaticofacial and zygomaticotemporal branches; and the posterior superior alveolar nerve, which supplies the maxillary molar dentition and the periodontal ligaments, gingivae, and pulp of the molars.

The branches of the maxillary nerve in the infraorbital canal include the middle superior alveolar nerve, which innervates the maxillary alveoli, gingivae, and periodontal tissues of the maxillary premolar area, and the anterior superior alveolar nerve, which innervates the maxillary alveoli, gingivae, and periodontal tissues of the central and lateral incisors and the canines.

The branches of the maxillary nerve in the face include the inferior palpebral nerve, which supplies the eyelids; the lateral nasal nerve, which supplies the skin on the nose; and the superior labial nerve, which supplies the upper lip and mucosa.

 

Periprocedural Care

Patient Education and Consent

Before a complete maxillary nerve block can be performed, informed consent must be obtained from the patient. The procedure and the likely complications must be explained. Maxillary nerve block is a relatively safe procedure, and complications are very rare. The most common complication is patient discomfort arising from numbness of a wide area of the face. Stressing to patients that this effect is transient and does not last beyond a few hours is important.

Equipment

Materials used in the performance of a maxillary nerve block include the following:

  • 25-gauge long needle (32-36 mm)

  • 22-gauge needle

  • 2-mL and 5-mL syringes

  • Cotton swab

  • Mouth props

  • Retractors

  • Local anesthetic: Generally, up to 2 mL of the drug (lidocaine 1-2%, mepivacaine 3%, or bupivacaine 0.5%) is required for the block; an additional 2 mL may be needed for skin infiltration.

  • Sterile drapes

Standard monitoring modalities (eg, pulse oximetry, noninvasive blood pressure [NIBP] monitoring, and electrocardiography [ECG]) should be available. Basic resuscitative drugs and equipment should be on hand in case of cardiorespiratory collapse.

Patient Preparation

The patient may be allowed to have a light breakfast or may be placed on nil per os (NPO) status, as warranted by the specific procedure to be performed after the block. Sedation can be accomplished with midazolam 3-5 mg or fentanyl 50-100 µg intravenously.

Patient positioning for maxillary nerve block varies, depending on the specific approach followed:

  • High tuberosity approach: The patient is supine with the chin tilted upward, and the operator stands on the same side as that to be blocked.

  • Greater palatine canal approach: The patient is supine with the chin tilted upward and the mouth open, and the operator stands on the same side as the side where the block is to be performed.

  • Coronoid approach: The patient is supine with the face turned to the contralateral side, and the operator stands on the same side as that to be blocked.

 

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

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

 

Medication

Medication Summary

The goal of pharmacotherapy is to reduce pain during the procedure.

Local Anesthetics, Amides

Class Summary

Local anesthetics are used for local pain relief.

Lidocaine (Xylocaine with epinephrine)

Lidocaine 1-2% with or without epinephrine (1:100,000 or 1:200,000 concentration) is used. Lidocaine is an amide local anesthetic used in 1-2% concentration. The 1% preparation contains 10 mg of lidocaine for each 1 mL of solution; the 2% preparation contains 20 mg of lidocaine for each 1 mL of solution. Lidocaine inhibits depolarization of type C sensory neurons by blocking sodium channels. Epinephrine prolongs the duration of the anesthetic effects from bupivacaine by causing vasoconstriction of the blood vessels surrounding the nerve axons.

Mepivacaine (Polocaine MPF)

Mepivacaine 2-3% prevents the generation and conduction of nerve impulses.

Bupivacaine and epinephrine (Marcaine with epinephrine, Vivacaine, Sensorcaine with epinephrine)

Bupivacaine 0.5% with or without epinephrine may be used. It decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses. Epinephrine prolongs the duration of the anesthetic effects from bupivacaine by causing vasoconstriction of the blood vessels surrounding the nerve axons.