Identification of the external branch of the superior laryngeal nerve during thyroidectomy.

OBJECTIVES: To determine the feasibility of identification of the external branch of the superior laryngeal nerve (EBSLN) during routine thyroidectomy and to describe the EBSLN position according to the Cernea classification system.

DESIGN: Prospective case series.

SETTING: Academic tertiary care center.

PATIENTS: One hundred twelve consecutive patients undergoing hemithyroidectomy or total thyroidectomy by the senior author between August 15 and December 31, 2007.

INTERVENTIONS: None.

MAIN OUTCOME MEASURE: Proportion of EBSLNs identified. Secondary outcome measures included EBSLN position according to Cernea classification and correlation with patient and gland characteristics.

RESULTS: Three of 178 EBSLNs (1.7%) could not be identified using the routine technique. The EBSLN was found in the highest-risk position (Cernea type 2b, crossing the superior vascular pedicle below the upper border of the gland) in 48.3% of cases, and in the lowest-risk position (Cernea type 1, crossing more than 1 cm above the upper border) in 7.3%. Specimens larger in weight and in dimension were correlated with type 2b nerves.

CONCLUSIONS: The EBSLN can be routinely identified during thyroidectomy. Moreover, many EBSLNs are in position to be at high risk of injury during ligation of the superior vascular pedicle.