Incidence of positive aspiration in the Gow-Gates mandibular block.

Abstract:  Evidence strongly suggests that rigorous precautions should be taken to avoid accidental intravascular injection of local anesthetic solutions. In this study, 3,000 patients each received a Gow-Gates mandibular block, resulting in a positive aspiration frequency of 1.6%. In the conventional inferior alveolar block technique, a range of positive aspirations from 3.6% to 22% has been noted. The Gow-Gates block has other important advantages over the conventional block. By observing the landmarks and the depth of penetration, it is possible to reinsert the needle with a reasonable assurance of a negative aspiration at the second attempt. The conventional technique suffers the major disadvantage that needle insertion techniques which produce the highest rates of clinically successful pain control run the greatest risk of vascular penetration. Operators skilled in the Gow-Gates technique should be able to achieve a positive aspiration rate of less than 2%. The technique is unique among oral nerve block procedures in that the preferred injection site for maximum efficacy is also the site that is least likely to result in vascular penetration.