Localization of the superior laryngeal nerve during carotid endarterectomy

Knowledge of the topographic anatomy is essential to prevent iatrogenic damage of the superior laryngeal nerve (SLN) in carotid endarterectomy (CEA). The purpose of this study was to analyze the anatomic relationship between the SLN and carotid arteries in order to prevent iatrogenic nerve injury. Anatomic dissections similar to CEA were performed bilaterally in 50 fresh human adult cadavers. The topography of the SLN was analyzed regarding its relationship with the carotid arteries. Furthermore, the distance between the external branch of the SLN and the point of bifurcation of the common carotid artery (dCAB) was analyzed regarding effects of gender, ethnicity, individual stature and side of the neck. The SLN was always located adjacent and posterior to the carotid arteries.The dCAB ranged from 20.3 mm below the point of bifurcation of the common carotid artery to 50.9 mm above this level (average 10.3 mm above). Most dissections (75%) showed the external branch of the SLN emerging from behind the carotid artery above the arterial bifurcation; in only 10% of cases did this nerve emerge from the artery below that anatomic reference. Based on Student's t-test, there were no significant differences in the dCAB between genders ( P=0.237), ethnicities ( P=0.410) and sides of the neck ( P=0.872). Moreover, tall stature was not significantly correlated with a shorter dCAB (linear regression: R(2)=0.009, P=0.357). We conclude that most SLNs were located above the carotid artery bifurcation, but anatomic variations occurred in 25% of the dissections. The dCAB was unaffected by gender, ethnicity, individual stature and side of the neck.