Internal Carotid Artery Classification Systems: An Illustrative Review

World Neurosurg. (2022) 163:41-49

The internal carotid artery (ICA) course has been discussed extensively. Several classification systems have attempted to delineate an accurate and helpful trajectory for microsurgical and endoscopic guidance, thus allowing a better neurosurgical performance while avoiding intraoperative complications. Also, the practicality of the classification systems has been emphasized for scholarly communication among disciplines. Nevertheless, the nomenclature of the ICA remains heterogeneous and confusing for health care professionals, trainees, and students.

We present an illustrative review of 8 notable ICA classification systems using lateral and anterior views as a rapid tool for neuroanatomic consultation. The appraisal of the vessel anatomy from different perspectives while recognizing their usefulness and limitations might provide a comprehensive understanding of the ICA, optimize the intraoperative performance, and facilitate communication

A standardized nomenclature for cervical spine soft-tissue release and osteotomy for deformity correction

Standardized nomenclature cervical osteotomies

J Neurosurg Spine 19:269–278, 2013

Cervical spine osteotomies are powerful techniques to correct rigid cervical spine deformity. Many variations exist, however, and there is no current standardized system with which to describe and classify cervical osteotomies. This complicates the ability to compare outcomes across procedures and studies. The authors’ objective was to establish a universal nomenclature for cervical spine osteotomies to provide a common language among spine surgeons.


A proposed nomenclature with 7 anatomical grades of increasing extent of bone/soft tissue resection and destabilization was designed. The highest grade of resection is termed the major osteotomy, and an approach modifier is used to denote the surgical approach(es), including anterior (A), posterior (P), anterior-posterior (AP), posterior-anterior (PA), anterior-posterior-anterior (APA), and posterior-anterior-posterior (PAP). For cases in which multiple grades of osteotomies were performed, the highest grade is termed the major osteotomy, and lower-grade osteotomies are termed minor osteotomies. The nomenclature was evaluated by 11 reviewers through 25 different radiographic clinical cases. The review was performed twice, separated by a minimum 1-week interval. Reliability was assessed using Fleiss kappa coefficients.


The average intrarater reliability was classified as “almost perfect agreement” for the major osteotomy (0.89 [range 0.60–1.00]) and approach modifier (0.99 [0.95–1.00]); it was classified as “moderate agreement” for the minor osteotomy (0.73 [range 0.41–1.00]). The average interrater reliability for the 2 readings was the following: major osteotomy, 0.87 (“almost perfect agreement”); approach modifier, 0.99 (“almost perfect agreement”); and minor osteotomy, 0.55 (“moderate agreement”). Analysis of only major osteotomy plus approach modifier yielded a classification that was “almost perfect” with an average intrarater reliability of 0.90 (0.63–1.00) and an interrater reliability of 0.88 and 0.86 for the two reviews.


The proposed cervical spine osteotomy nomenclature provides the surgeon with a simple, standard description of the various cervical osteotomies. The reliability analysis demonstrated that this system is consistent and directly applicable. Future work will evaluate the relationship between this system and health-related quality of life metrics.