Superior laryngeal nerve block: an anatomical study comparing two techniques

Abstract

Study ObjectiveTo determine whether an anterior approach is as successful as the conventional posterior approach to superior laryngeal nerve block. DesignProspective observational study. SettingUniversity anatomy laboratory. Patients20 formalin-fixed adult human cadavers. MeasurementsSimulated superior laryngeal nerve blocks were performed by a single operator using 3 mL of 0.01% analine blue dye with a 23-gauge Quincke tip needle. Two different landmark techniques were used on each undissected cadaver: 1) the conventional posterior approach using the hyoid bone as a palpable landmark, with injection at the posterior third of the thyrohyoid membrane; and 2) the anterior approach, using the anterior thyroid notch of the thyroid cartilage, with injection at the anterior third of the thyrohyoid membrane. The spread of analine dye was observed. An injection was deemed successful if the entire paraglottic space was stained or the superior laryngeal nerve stained as it entered the paraglottic space. Main ResultsBoth techniques were equally successful after 40 injections. ConclusionThere was no significant difference in success in staining the superior laryngeal nerve in human cadavers between the conventional posterior approach and an anterior approach.