External Validity of the Novel Surrogate Measures for Occipitocervical Alignment

Ahmadreza  Mirbolook; Masoomeh  Raoufi; Yeganeh  Yousefifar; Mobin  Forghan; Mohammad Sadegh  Fakhari; Mohammadreza  Bozorgmanesh

doi:10.18502/jost.v10i4.17357

Ahmadreza Mirbolook Associate Professor, Department of Orthopedic Surgery, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Masoomeh Raoufi Assistant Professor, Department of Radiology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Yeganeh Yousefifar General Practitioner, Department of Radiology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mobin Forghan Assistant Professor, Department of Surgery and Orthopedics, Ardabil University of Medical Sciences, Ardabil, Iran
Mohammad Sadegh Fakhari Research Assistant, Student Research Committee, Arak University of Medical Sciences, Arak, Iran
Mohammadreza Bozorgmanesh Orthopedic Surgeon, Department of Spine Surgery, Shahid Beheshti University of Medical Sciences, Tehran, Iran

DOI: https://doi.org/10.18502/jost.v10i4.17357

Keywords: Cervical Vertebrae; Spinal Fusion; Diagnostic Imaging; Radiology

Abstract

Background: Occipitocervical fusion (OCF) is a rare and often challenging surgical procedure. Several methods have been introduced to obtain the best measures for occipitocervical alignment. The mandible-C2 angle was first introduced in 2020. In this study, we aimed to evaluate the out-of-sample validity of these measures.

Methods: We retrospectively studied 274 lateral cervical radiographs of patients aged 1 to 87 years with no cervical pathology evident on X-ray. A board-certified radiologist and a second-year radiology resident performed the measurements on five specific angles as suggested by Bellabarba. The five angles measured consisted of: 1) anterior C2 body/anterior mandible angle (AB/AM), 2) anterior C2 body/posterior mandible angle (AB/PM), 3) posterior C2 body/anterior mandible angle (PB/AM), 4) posterior C2 body/posterior mandible angle (PB/PM), and 5) occipito-C2 angle (OC2A).

Results: Inter-rater correlation data were calculated for single and average measures. The inter-rater agreement for individual angle measures of O-C2A, AB/AM, AB/PM, PB/AM, and PB/PM were 0.49, 0.11, 0.25, 0.33, and 0.49, respectively. The intraclass correlation coefficient (ICC) for average measures of O-C2A, AB/AM, AB/PM, PB/AM, and PB/PM were 0.66, 0.20, 0.40, 0.50, and 0.66, respectively.

Conclusion: Our study did not find statistically significant evidence to confirm that these angles were dependable indicators of occipitocervical alignment, except for the PB/PM angle, which showed a validity comparable to our reference angle