Introduction: Cervical spinal osteotomies are powerful techniques to correct rigid cervical spinal deformity. However, many variations exist, and there is no current standardized system to describe and classify cervical osteotomies. This complicates the ability to compare outcomes across procedures and studies. Our objective was to establish a universal cervical spinal osteotomy classification system in order to provide a common language among spine surgeons.
Methods: A proposed classification with 7 anatomical grades of increasing extent of bone resection and destabilization was designed. The grades consisted of a major osteotomy and an approach modifier to denote a surgical approach of anterior (A) and posterior (B) including: A, P, AP, PA, APA, or PAP. The reviewers were then asked to identify any other osteotomies used in the clinical case denoted as the minor osteotomy. The classification system was evaluated by 9 reviewers through 25 different radiographic clinical cases. The review was performed twice at 1 week intervals. Reliability was assessed using Fleiss’ Kappa coefficients.
Results: The average intra-rater reliability was classified as “almost perfect”: major osteotomy 0.93 (0.92-1.0), approach modifier 0.98 (0.92-1.0), and minor osteotomy 0.85 (0.76-1.0). The average inter-rater reliability for the two readings was the following: major osteotomy 0.66 (“substantial agreement”), approach modifier 0.90 (“almost perfect”), and minor osteotomy 0.27 (“fair agreement”). Analysis of only major osteotomy + approach modifier yielded a classification that was “almost perfect” with average intra-rater reliability of 0.91 (0.82-1.0) and inter-rater reliability of 0.87 and 0.86 for the 2 reviews.
Conclusions: The proposed cervical spinal osteotomy classification system 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.
Patient Care: This research improves patient care by establishing a cervical spinal osteotomy classification system that can enhance communication among surgeons and facilitate comparison of outcomes across procedures and studies relating to cervical deformity.
Learning Objectives: By the conclusion of this presentation, participants should: 1) identify the cervical spinal osteotomy classification grades, 2) appreciate that this system was observed to have excellent reliability, and 3) be aware that this may serve as the foundation for common cervical spinal osteotomy language and future work in cervical spine surgery outcomes.