A new classification of cavernous segment of the internal carotid artery.

INTRODUCTION

The shape of the cavernous segment of the internal carotid artery (CSICA) is various in different people, which makes it difficult to be located and causes a higher possibility of injury in the transsphenoidal approach. Hence, a comprehensive study of the CSICA and a meaningful classification of it are rather helpful to the approach and other operations related to the CSICA.

PURPOSE: Our study aimed to make a comprehensive measurement and classify the CSICA into different types so as to better describe its shape and position.

MATERIALS AND

METHODS

Computed tomographic angiography images of 146 internal carotid arteries in individuals (76 males and 70 females) ranging in age from 17 to 78 years (mean, 49.49 y) were reviewed. We measured the distances between the bilateral CSICA at 5 positions in the coronal plane and the angle of the posterior curve segment in the sagittal plane. According to these statistics, we divided the CSICA into different types.

RESULTS

The distance between the medial walls of the bilateral internal carotid artery is similar to the previous relevant study. We classified the horizontal segment of the CSICA into 5 types: types 1, 2, 3, 4, and 5. Among the individuals we measured, the proportion of each type is 8.2%, 25.3%, 39.7%, 19.9%, and 6.9%. In addition, the posterior curve segment of the CSICA can be classified into 4 types: types Z, A, S, and O. Among the 292 sides we measured, the proportion of each type is 22.6%, 17.8%, 21.9%, and 37.7%. Furthermore, 80.8% of the people with bilateral sides of type O belonged to type 3 and 72.7% of the people with bilateral sides of type Z belonged to type 2.

CONCLUSIONS

The detailed classification of the CSICA is helpful to understand its complexity. The classification of the CSICA can guide the surgeons in the transsphenoidal approach to avoid injuring and to simplify the location of the whole CSICA.