Interrater and intrarater agreement and reliability of ratings made using the Zaidi\u2013Dayal and Richards\u2013Jabbour scales for the shape of the foramen magnum

Sayel H Alzraikat,Rand Y Omari,Justin Z Amarin,Osama A Samara,Haya H Suradi,Darwish H Badran,Afnan N Ghafel

doi:10.1038/s41598-019-54764-0

Abstract

Anatomists and radiologists use the Zaidi–Dayal and Richards–Jabbour scales to study the shape of the foramen magnum. Our aim is to measure the interrater and intrarater agreement and reliability of ratings made using the two scales. We invited 16 radiology residents to attend two sessions, four weeks apart. During each session, we asked the residents to classify the shape of the foramen magnum in 35 images using both scales. We used Fleiss’ κ to measure interrater reliability and Cohen’s κ to measure intrarater reliability. The interrater reliability of ratings made using the Zaidi–Dayal scale was 0.34 (0.26–0.46) for session one and 0.30 (0.24–0.39) for session two, and the intrarater reliability was 0.39 (0.34–0.44). The interrater reliability of ratings made using the Richards–Jabbour scale was 0.14 (0.10–0.19) for session one and 0.12 (0.09–0.17) for session two, and the intrarater reliability was 0.11 (0.07–0.15). In conclusion, the interrater and intrarater agreement and reliability of ratings made using the Zaidi–Dayal and Richards–Jabbour scales are inadequate. We recommend an objective method by Zdilla et al. to researchers interested in studying the shape of the foramen magnum.

Highlights

The size of the foramen magnum is often expressed using the anteroposterior and transverse diameters
The scales are used to classify shapes that occur in the normal population
Abnormal shapes may indicate pathology: An asymmetric foramen magnum occurs with craniovertebral junction anomalies and craniosynostosis, and a keyhole-shaped foramen magnum occurs with hydrolethalus syndrome[4]

Summary

Introduction

The size of the foramen magnum is often expressed using the anteroposterior and transverse diameters. The diameters vary by age, biological sex, race, and stature—albeit to a small extent in the normal population[2,3]. Abnormal diameters may indicate pathology: A small foramen magnum occurs with achondroplasia and other skeletal disorders, and a large foramen magnum occurs with chronic increased intracranial pressure, syringomyelia, and Arnold–Chiari malformation. The shape of the foramen magnum is often described using one of two nominal scales[5,6]. The scales are used to classify shapes that occur in the normal population. Both scales are appropriate for use in cadaveric and radiographic studies, and the most common users are anatomists and radiologists[2]. The shape of the foramen magnum varies to a large extent between populations[2]. Our aim is to measure the interrater and intrarater agreement and reliability of ratings made using the two scales

Objectives

Methods

Conclusion