# Dynamic ultrasound guided assessment of pelvic ring injury measurement (PRIME) for traumatic symphysis diastasis

## TL;DR

This study shows that ultrasound can effectively measure pelvic injuries, especially when the separation is more than 2.5 cm.

## Contribution

The study introduces a dynamic ultrasound method for assessing pelvic injuries in cadavers with high accuracy for larger separations.

## Key findings

- Ultrasound sensitivity for symphysis diastasis was 0.73 in control cadavers.
- Sensitivity increased to 0.82 for diastasis above 2.5 cm.
- Dynamic assessment showed the highest sensitivity of 0.91.

## Abstract

Assessment of pelvic ring injuries in the pre-clinical and trauma bay setting represents a challenge for the treating trauma team. The objective of the present project was to conduct a pre-clinical trial to investigate the feasibility and accuracy of ultrasound (US) guided assessment of symphyseal diastasis, of cadavers with pelvic ring injuries.

This is a prospective, anatomical, interventional and radiological cadaveric laboratory investigation. Cadavers were prepared with a pelvic ring injury (symphyseal diastasis). Eleven trauma surgeons performed an ultrasound-guided assessment of the symphyseal diastasis. The intervention was performed in four formalin-fixes cadavers. One served as the control and the other were prepared to have a set of standardized symphysis diastasis. The diastasis was grouped into “below 2.5 cm” and “above 2.5 cm”. Trauma surgeons were blinded to the symphysis diastasis and performed an ultrasound-guided assessment of the anterior pelvic ring. Sensitivity and specificity analyses were performed.

The ultrasound measure of the control provided a sensitivity of 0.73 (95%CI 0.39 TO 0.94). The sensitivity of the ultrasound measure increased with increasing diastasis of the symphysis (Group above 2.5 cm 0.82, 95%CI 0.48 to 0.98). The highest sensitivity was measured in the dynamic assessment of the symphysis closure (0.91, 95%CI 0.59 to 1.0). Specificity was lowest in Group below 2.5 (0.73, 95%CI 0.39 to 0.94).

Ultrasound-guided assessment of symphyseal diastasis is feasible and shows high diagnostic accuracy, especially for diastasis > 2.5 cm and during dynamic evaluation. Sensitivity and predictive values improved with larger displacements, while detection of smaller diastasis remained limited. These findings support the potential use of ultrasound as a rapid, non-invasive tool in early pelvic trauma assessment.