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Mandibular Nerve Block Technique

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

Approach Considerations

The following 3 techniques are used to perform a mandibular nerve block[1, 2] :

  • Gow-Gates technique
  • Vazirani-Akinosi technique
  • Coronoid approach

For a clear understanding of the technical descriptions that follow (see below), it is important to be conversant with some dental anatomic terminology. These terms may be illustrated by considering the anatomy of the second maxillary molar tooth.

The second maxillary molar tooth is placed between the first and third molar teeth and is the seventh tooth from the midline. The visible part of the tooth is called the crown, and the parts covered by the gum are the 3 roots of the tooth. The dividing line that separates the roots from the crown is called the cervical line.

The crown has the following 5 surfaces:

  • Occlusal
  • Buccal
  • Lingual (palatal)
  • Mesial
  • Distal

The occlusal, buccal, and lingual surfaces are self-explanatory, referring to those particular surfaces of the tooth. The mesial surface is the anterior surface of the tooth—in this case, the surface adjoining the first molar tooth. The distal surface is the posterior surface—in this case, the surface adjoining the third molar tooth.

The buccal surface of the tooth has the following 2 protuberances or cusps, which are separated by the buccal groove:

  • An anterior protuberance, called the mesiobuccal cusp
  • A posterior protuberance, called the distobuccal cusp

Similarly, the lingual surface has a mesiolingual cusp and a distolingual cusp, which are separated by the lingual groove.

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Techniques for Mandibular Nerve Block

Gow-Gates technique

This technique is mainly indicated in patients undergoing dental procedures in whom inferior alveolar nerve block does not provide adequate analgesia owing either to anatomical variation or due to accessory nerve supply. This approach provides true mandibular nerve block as it blocks the trunk of the nerve before it divides into its three main terminal branches. The incidence of intravascular injection is also lesser with this approach.

A disadvantage of this approach is that there is undesired anesthesia of the lower lip and temporal region. The onset time of the block is also prolonged. 

The patient is placed in a semisupine position or on a dental chair with the operator standing on the same side as the block to be performed.[3, 4, 5] The mouth is opened as wide as possible. This is essential for the success of this block. Anatomic landmarks include the following:

  • Corner of the mouth
  • The intertragic notch
  • Distolingual cusp of the second maxillary molar tooth

The aim is to reach the neck of the mandibular condyle.

The second maxillary molar tooth is identified, and a needle is inserted at the level of the mesiolingual cusp along the medial side of the mandibular ramus (see the image below). The point of insertion is much higher than that for an inferior alveolar nerve (IAN) block. The needle is inserted in such a way that it lies parallel to an imaginary line drawn from the intertragic notch to the angle of the mouth.

The Gow-Gates approach for mandibular nerve block The Gow-Gates approach for mandibular nerve block

The needle is advanced by 2.5 cm so as to contact the bony neck of the mandibular condyle. It is then slightly withdrawn, and negative aspiration is confirmed in 2 planes. Finally, 1.8 mL of local anesthetic is injected slowly over 1 minute. This blocks the IAN and its branches and the lingual, mylohyoid, auriculotemporal, and buccal nerves.

Vazirani-Akinosi (closed-mouth) technique

The Vazirani-Akinosi technique has several advantages over the Gow-Gates technique.[6, 7] It is useful in trismatic patients and those with ankylotic temporomandibular joint; in addition, it is less traumatic and has a lower complication rate. However, the Vazirani-Akinosi technique is less effective than the Gow-Gates technique. Recent studies have not shown any difference in the quality of pain relief with either of the approaches.[8]  This approach is contraindicated if the patient has an infection or inflammation involving the pterygomandibular region or maxillary tuberosity. The main advantages with this approach include a faster onset of action, lesser post-procedure complications, and lesser pain during injection.

The patient is placed in a semisupine position or on a dental chair with the mouth closed. The operator stands on the same side as the block to be performed. Anatomic landmarks include the following:

  • Gingival margin over the second and third maxillary molars
  • Pterygomandibular raphe

The aim is to enter the pterygomandibular space where the IAN, lingual nerve, and mylohyoid nerve are present. This space is bordered laterally by the ramus of mandible, medially and inferiorly by the medial pterygoid muscle, posteriorly by the parotid gland, and anteriorly by buccinators muscle.

The cheek is retracted with a retractor, and the patient is asked to occlude his or her teeth gently. The needle is inserted over the medial aspect of the mandibular ramus, parallel to the occlusal plane at the height of the mucogingival junction of the second and third molars (see the image below). The needle is bent slightly to decrease the chance of entering the muscle belly.

Vazirani-Askinosi technique (a.) point of insertio Vazirani-Askinosi technique (a.) point of insertion is medial to the mandibular ramus. (b) the needle is inserted till the hub of the needle is distal to the second upper molar.

The needle is then advanced through the mucous membrane and buccinator muscle to enter the pterygomandibular space. The needle is advanced until the hub is level with the distal surface of the second molar. After negative aspiration, 1.8 mL of local anesthetic is injected slowly over 1 minute.

Coronoid approach

The patient is placed in a supine position with the mouth in a neutral position. The coronoid notch on the side of the block is identified by opening and closing the mouth a few times.

After skin preparation, a 22-gauge needle is inserted at the middle of the notch and advanced to a depth of about 1-2 inches in a plane perpendicular to the base of the skull until the lateral pterygoid plate is reached. The tip of the needle is then withdrawn slightly and redirected posteriorly and inferiorly so that it goes beyond the lateral pterygoid plate. After redirection of the needle, paresthesias in the mandibular region are elicited at a depth of about 1 cm. After aspiration, 3-5 mL of local anesthetic solution is slowly injected.

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Complications

If a large volume of the local anesthetic is administered or an inadvertent intravascular injection has taken place, the patient may manifest a systemic toxic response to the local anesthetic used. This may involve minimal to moderate symptoms (eg, anxiety, numbness, dizziness, weakness, and tremors), but in some cases, it can result in central nervous system (CNS) and cardiovascular collapse.

An allergic reaction may develop to the preservatives added to the local anesthetic (eg, methylparaben or sodium metabisulfite) or to an ester-group local anesthetic.

Persistent paresthesia and numbness may be due to trauma to the nerve or local hematoma formation.

Needle-track infection is possible. This can be avoided by employing single-use syringes and needles, using disinfectants, and avoiding areas with active infection.

Hematoma formation is possible. Edema and sloughing of tissues, although rare, can occur.

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Contributor Information and Disclosures
Author

Anusha Cherian, MBBS, MD, DNB Assistant Professor, Department of Anesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, India

Disclosure: Nothing to disclose.

Coauthor(s)

Nanda Kishore Maroju, MBBS, MS, DNB, MRCS Assistant Professor of Surgery, Jawaharlal Institute of Postgraduate Medical Education and Research, India

Nanda Kishore Maroju, MBBS, MS, DNB, MRCS is a member of the following medical societies: Royal College of Surgeons of Edinburgh

Disclosure: Nothing to disclose.

Chief Editor

Meda Raghavendra (Raghu), MD Associate Professor, Interventional Pain Management, Department of Anesthesiology, Chicago Stritch School of Medicine, Loyola University Medical Center

Meda Raghavendra (Raghu), MD is a member of the following medical societies: American Society of Anesthesiologists, American Society of Regional Anesthesia and Pain Medicine, American Association of Physicians of Indian Origin

Disclosure: Nothing to disclose.

References
  1. Budenz AW, Osterman SR. A review of mandibular anesthesia nerve block techniques. J Calif Dent Assoc. 1995 Sep. 23(9):27-34. [Medline].

  2. Gaum LI, Moon AC. The "ART" mandibular nerve block: a new approach to accomplishing regional anesthesia. J Can Dent Assoc. 1997 Jun. 63(6):454-9. [Medline].

  3. Sisk AL. Evaluation of the Gow-Gates mandibular block for oral surgery. Anesth Prog. 1985 Jul-Aug. 32(4):143-6. [Medline]. [Full Text].

  4. Gow-Gates G, Watson JE. Gow-Gates mandibular block--applied anatomy and histology. Anesth Prog. 1989 Jul-Oct. 36(4-5):193-5. [Medline].

  5. Kafalias MC, Gow-Gates GA, Saliba GJ. The Gow-Gates technique for mandibular block anesthesia. A discussion and a mathematical analysis. Anesth Prog. 1987 Jul-Aug. 34(4):142-9. [Medline]. [Full Text].

  6. Sisk AL. Evaluation of the Akinosi mandibular block technique in oral surgery. J Oral Maxillofac Surg. 1986 Feb. 44(2):113-5. [Medline].

  7. Haas DA. Alternative mandibular nerve block techniques: a review of the Gow-Gates and Akinosi-Vazirani closed-mouth mandibular nerve block techniques. J Am Dent Assoc. 2011 Sep. 142 Suppl 3:8S-12S. [Medline].

  8. Malamed SF. Is the mandibular nerve block passé?. J Am Dent Assoc. 2011 Sep. 142 Suppl 3:3S-7S. [Medline].

 
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Branches of the mandibular nerve
Vazirani-Askinosi technique (a.) point of insertion is medial to the mandibular ramus. (b) the needle is inserted till the hub of the needle is distal to the second upper molar.
The Gow-Gates approach for mandibular nerve block
 
 
 
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