Radiographic Assessment of Pelvic Inlet and Outlet View Angles in the Ethiopian Population.

Abstract

Background: Accurate radiographic assessment is pivotal in evaluating trauma patients with suspected pelvic ring disruptions. The conventional approach of using anteroposterior, 45° inlet, and 45° outlet radiographs for the evaluation of pelvic injury may not consistently align with varying lumbopelvic anatomy. This study aimed to determine the ideal pelvic inlet and outlet radiographic angles when there is limited access to advanced imaging (e.g., computed tomography [CT]) for assessing clinically relevant pelvic osseous landmarks and to investigate variations based on age, sex, and sacral dysmorphism.

Methods: This cross-sectional study investigated patients who were ≥18 years of age who had no traumatic injuries or pelvic ring pathology; we reviewed abdominopelvic CT scans that were obtained between January 1, 2023, and June 30, 2023. Midsagittal reconstruction and 3D rendering of 148 CT scans facilitated the measurement of pelvic inlet and outlet angles. Standard techniques that were based on previous studies were used to determine the ideal angles. Statistical analyses investigated mean pelvic inlet and outlet angles as well as correlations with age, sex, and sacral dysmorphism.

Results: The mean pelvic inlet angle was 23.8° ± 8.4° (95% confidence interval [CI]: 22.4° to 25.2°), and the mean outlet angle was 40.1° ± 5.9° (95% CI: 39.2° to 41.1°). Male patients exhibited greater inlet angles (27° versus 20°), whereas female patients had greater outlet angles (41° versus 39°). Pelves with dysmorphism showed a 3.6° increase in outlet angles when compared with those with normal sacral anatomy. An inverse relationship between age and inlet angle was observed.

Conclusions: This study highlights that the recommended 45° angle for pelvic inlet and outlet views may not optimally align with the anatomy of the Ethiopian population. The findings suggest that the ideal inlet and outlet angles for this population are 25° and 40°, respectively. Understanding these variations is crucial for optimizing pelvic radiographic views in trauma evaluation, potentially leading to more accurate assessments and improved patient care in this demographic.

Level of evidence: Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.