The Vazirani-Akinosi technique is a specific method of nerve block in the mandibular region, carried out with the mouth closed. The technique spread after Joseph Akinosi’s 1977 publication; a similar procedure, however, had been described by Vazirani in 1960, even before the introduction of the Gow-Gates technique. In agreement with Malamed, the eponym currently used therefore recognises both authors.
Effects and indications for use of the Vazirani-Akinosi method
The area of distribution of the anaesthesia includes a) the corresponding dental arch, b) the body of the jaw and the inferior ramus, c) the gingiva/mucosa and vestibular periosteum, anterior to the mental foramen e) the area of distribution of the lingual nerve: 2/3 of the anterior of the tongue and floor of the mouth, the gingiva/mucosa and lingual periosteum.
The main indication, already anticipated, is trismus: classically this is contraction of the masticatory musculature which prevents the performance of effective inferior alveolar anaesthesia, for example, in cases of pulpitis or an abscess of a lower molar. This method may also be proposed in less extreme cases of patients with limited mandibular opening.
The technique also has some practical advantages such as, for example, the lower aspiration rate (<10%) than that of the usual alveolar nerve anaesthesia.
Technique for performing the Vazirani-Akinosi inferior alveolar nerve block
Malamed recommends using a long needle, 25 or 27 G. The insertion area is the soft tissues lining the medial border of the mandibular ramus, at the level of the mucogingival line next to the upper third molar. The point is therefore particularly close to the maxillary tuberosity and is cranial with respect to the site of the conventional technique and caudal compared to that of Gow-Gates. It is the point where the inferior alveolar, lingual and mylohyoid nerves start to run downwards.
The patient is placed supine or semi-seated and the operator palpates the coronoid Notch then opens out the soft tissues of the cheek and upper vestibule. The syringe is inserted parallel to the occlusal plane and moves in a posterior and slightly lateral direction, the latter being designed to follow the flaring of the mandibular ramus. In the past it was suggested that the needle be bent towards the medial side of the mandibular ramus: the method recommended today is the original one, with the needle aligned with the body of the device used to perform the injection. The soft tissues are about 25 mm deep, there is no contact with the bone, and the tip of the needle is located in the centre of the pterygomandibular space. The fact that the second phase of the procedure has to be conducted “blind” is perceived by some authors to be the main disadvantage of the method. The onset of the anaesthetic effect on the dental pulp is observed within about 5 minutes.