Background

A complete maxillary nerve block is not necessary because large area of anesthesia which is provided by maxillary nerve block are maxillary teeth, nearby soft tissues, zygomatic, dural, and temporal regions and maxillary sinus mucosa. All of these parts are insufficient for most procedures. Only a small area like a single tooth or targeted nerve is needed to be anesthetized. This also minimizes discomfort of the patient. 

Indications

This procedure is performed in the following: 

For many teeth and nearby areas may surpass the toxic dose of anesthesia because of the complexity and discomfort in individual nerve blocks. 

Large canine abscesses need more local anesthesia for specific nerve blocks, but MNB can be done with a low dosage of drug. 

Development of abscess or infection may lead to failure of local nerve blocks. MNB can be helpful which can be given away from the site of infection. 

Maxillary surgery can be performed without or with general anesthesia. 

To manage the post-operative pain after the surgery of maxilla. 

Painful conditions in the maxilla areas which do not respond to the systemic analgesics. 

Certain cases of trigeminal neuralgia. 

Contraindications

MNB is contraindicated for: 

Patients who denied for the procedure 

Patients who are hypersensitive to local anesthesia 

Any infection presents on injection site 

Patients who are taking medication which changes the hemostasis 

Patients who are suffering from coagulopathic abnormality. 

Outcomes

When MNB procedure is performed properly, it provides excellent and long – lasting pain relief. It decreases the need for general anesthesia or sedatives. Incomplete nerve block and local or systemic effects of anesthesia are the potential complications of this procedure. Some patients experience short-term numbness or tingling. 

At the injection site, some swelling may occur, and it usually subsides quickly. Bleeding can be rapid if the maxillary artery is lacerated by the needle, and nerve injury when it occurs, can be prolonged with resultant numbness or dysesthesia. If the block is effective in the relief of pain and thus makes the procedure smoother, patient satisfaction is high. Clinicians should track patient outcomes and follow-up for delayed effects/complications. Such potential outcomes might leave clinicians much better prepared to carry out and manage the maxillary nerve block for better results and patient safety. 

Equipment

Material which are needed to perform MNB: 

Cotton swab 

Retractors 

Sterile drapes 

22-gauge needle 

5mL and 2mL syringes 

32-36mm of 25-gauge long needle 

Mouth props 

Local anesthesia up to 2mL of 3% mepivacaine, 1 to 2% lidocaine, or 0.5% bupivacaine is required for the procedure. For infiltration of skin, an additional 2mL may be needed. 

Patient preparation

The patient can either be permitted to eat a light breakfast or be placed on NPO (nil per os) status, depending on the requirements of the procedure following the block. Sedation may be achieved with an intravenous administration of 50-100µg of fentanyl or 3mg to 5mg of midazolam. 

Patient position

Greater palatine canal approach: The patient lies supine with the mouth open, and chin tilted upward. The operator will stand on the same side at which the block needs to be administered. 

High tuberosity approach: The patient lays with the chin tilted upwards and the operator will stand on the same side at which the block needs to be administered. 

Coronoid approach: The patient is positioned supine with the face turned to the opposite side, and the operator stands on the same side where the block will be performed. 

Approach considerations

The medical history of patients must be evaluated for any contraindications or diseases which can interfere with procedure. A MNB must be determined depending on the evaluation of discomfort and anatomy of patient. Indications and alternatives should be thoroughly considered, as should alternative anesthesia techniques. The patient should be NPO and should be sedated if appropriate. Needle type and the injection technique to be used should be decided based on the needs of the patient and the local anesthetic to be applied. Post-procedure care should review the effectiveness of the block and whether the patient is comfortable.  

Technical considerations

There are 3 different techniques to perform MNB technique: Coronoid approach, Greater palatine canal approach, and High tuberosity approach 

Coronoid approach: 

This approach is a surgical procedure that is performed with imaging guidance, in which the patient opens and closes his mouth to palpate in front of and below the tragus. The area is cleaned with povidone-iodine and a 22-gauge needle is advanced to the center of the coronoid notch, on the lateral pterygoid plate. Adjust the needle by pulling it slightly, then turn the needle more upward and downward, pushing to 1 cm. Withdraw slightly a second time by 5mm to check for negative aspiration, then deposit 5 ml to 10 ml of drug slowly. 

Areas that are sensitized on the side of the block are: 

Side of nose, upper lip, and cheek 

The skin of the lower eyelid 

Bone and buccal periosteum 

Pulpal area of all teeth 

Greater palatine canal approach: 

The greater palatine canal approach is a common method to block the maxillary nerve while it travels through the pterygopalatine fossa. Although it is the most common and successful, this technique is absolutely contraindicated if the canal cannot be found or negotiated.  

The greater palatine foramen can be identified on the palate by using a cotton swab. A 25-gauge needle is inserted in front of foramen and a small amount of anesthesia is given. Wait for 3 minutes to 5 minutes. Insert the needle to 3 cm, and 1.8 ml of local anesthesia is inserted if there is no resistance. If there is resistance, then the needle is redirected and reinserted at new angle. 

Greater palatine canal approach of MNB 

High tuberosity approach: 

This approach targets the maxillary nerve in the pterygopalatine fossa. It provides anesthesia to hemimaxialla and nearby tissues. First step is to identify and clean the highest point on mucobuccal fold to perform the block. Insert needle at a 45° angle and 3 cm. Slowly administer 1.8 ml of local anesthesia. This technique has a 95% success rate to achieve nerve block. If a needle is injured in the maxillary artery, then there is a risk of hemorrhage. 

Complications

Complications linked to local anesthesia are: 

Toxicity because of the administration of large amounts of anesthesia and allergic reactions 

Complications linked to the technique: 

Possible needle tract infection 

Block of nerves in the nearby areas of the procedure 

Nasal cavity penetration 

Formation of retrobulbar hematoma  

Numbness and persistent paresthesia 

Sloughing of tissues and edema 

References

Maxillary nerve block via the greater palatine canal: An old technique revisited – PMC (nih.gov) 

References

Maxillary nerve block via the greater palatine canal: An old technique revisited – PMC (nih.gov)