Neural blockade anaesthesia of the mandibular nerve and its terminal branches: rationale for different anaesthetic techniques including their advantages and disadvantages

Abstract

Anaesthesia of structures innervated by the mandibular nerve is necessary to provide adequate pain control when performing dental and localised surgical procedures. To date, numerous techniques have been described and, although many of these methods are not used routinely, there are some situations where their application may be indicated. Patient factors as well as anatomical variability of the mandibular nerve and associated structures dictate that no one technique can be universally applied with a 100% success rate. This fact has led to a proliferation of alternative techniques that have appeared in the literature. This selective review of the literature provides a brief description of the different techniques available to the clinician as well as the underlying anatomy which is fundamental to successfully anaesthetising the mandibular nerve.

Figures

Figure 1

Transverse section of the mandibular ramus at the level just superior to the lingula. (R: Ramus, IAN: inferior alveolar nerve, IAV: inferior alveolar vein, IAA: inferior alveolar artery, SML: sphenomandibular ligament, MP: medial pterygoid muscle, B: buccinator, PMR: pterygomandibular raphe, SCM: superior constrictor muscle, TT: tendon of temporalis L: lingula). The needle is shown passing through the pterygomandibular space where it is directed to an area of bone just superior to the lingula, L. This is the level at which an IANB should be administered.

Figure 2

Photograph of the mandible where the needle tip is directed toward the area of bone just superior to the lingula. This positioning of the needle will allow for local anaesthetic deposition in a location in close proximity to the IAN and associated vessels, yet minimising the risk of damaging them. This photograph reflects where local anaesthetic is injected with the direct and indirect IANB (CN: Coronoid notch, L: Lingula).

Figure 3

Intraoral photograph of the left side of the oral cavity showing the injection sites for different mandibular block techniques. The pterygotemporal depression exists between the pterygomandibular fold and coronoid notch and represents the area where a direct or indirect IANB is administered in the mediolateral plane. The height at which this block is given is approximately the level of the coronoid notch. In contrast, the Gow-Gates mandibular block is administered at a much higher level. The mesiopalatal cusp of the upper second molar determines the height of the injection while the site in the mediolateral plane is the area of tissue just posterior to the upper second or third molar (PTD: pterygotemporal depression, PMF: pterygomandibular fold, CN: coronoid notch, 1: area where a direct/indirect IANB would be administered, 2: area where a Gow-Gates mandibular block would be administered).

Figure 4

Photograph of the mandible showing the positioning of the needle tip when administering the anterior IANB. Note that the location of the needle tip is a considerable distance from where the IAN would be expected. This technique relies heavily on the ability of local anaesthetic to diffuse throughout the pterygomandibular space (NC: neck of Condyle, CP: coronoid process, L: lingula).

Figure 5

Photograph of the mandible showing the ideal needle tip position when administering the Gow-Gates mandibular block technique. The intended target area for the needle is the lateral condylar neck region, below the insertion of the lateral pterygoid muscle and the attachment of ligaments associated with the temporomandibular capsule (CN: condylar neck, CP: coronoid process).

Figure 6

Photograph of the mandibular ramus from a medial view showing the needle tip positioning required for the Akinosi closed mouth mandibular nerve block technique. Note that the needle should not contact bone during needle insertion. The needle tip slips along the medial aspect of the ramus to its intended target area, the loose areolar tissue within the superior reach of the pterygomadibular space (CN: condylar neck, CP: coronoid process, L: lingula).