Superior laryngeal nerve preservation in peri-apical surgery by mobilization of the viscerovertebral angle.

Iatrogenic lesions of the superior laryngeal nerve (SLN) are much more common than is generally recognized. Since injury to this nerve may cause transient or even persistent changes either in quality of voice or in deglutition, an attempt should be made to localize and identify the nerve during surgery. This study included 74 patients who underwent surgical dissection near the thyroid apex in the neck. Effective prevention of SLN injury during surgery was achieved by anatomical localization of the nerve in the viscerovertebral angle and its functional identification with the nerve stimulator. Post-operative analysis consisted of subjective interview, rigid laryngoscopy, acoustic analysis, laryngeal videostroboscopy and cricothyroid electromyography. Four patients complained of post-operative voice changes; two were diagnosed as SLN injury (2.4 per cent), one as reflux laryngitis and the fourth as intubation granuloma. Surgical access to the SLN in the periapical area may be achieved through mobilization of the viscerovertebral angle. The use of a nerve stimulator during difficult situations should keep SLN injury at a minimum.