Accuracy of Ultrasonography in Retained Soft Tissue Foreign Bodies: A Systematic Review and Meta-analysis

Jack Lemon | MS4

The article:

Davis, J, Czerniski, B, Au, A, MD, Adhikari, S, MD, MS, Farrell, I, MD, Fields, JM, MD. Diagnostic Accuracy of Ultrasonography in Retained Soft Tissue Foreign Bodies: A Systematic Review and Meta-analysis. Academic Emergency Medicine, 2015 Jul;22(7):777-87. doi: 10.1111/acem.12714.

The Idea:

Ultrasound is widely used in exploring open wounds for soft tissue foreign bodies, but overall the sensitivity and specificity has not been well characterized across multiple studies. This Meta-analysis sought to determine the sensitivity and specificity of ultrasound for identifying soft tissue foreign bodies.

The Study:

The authors identified 5,689 articles by querying multiple journal databases and used exclusion and inclusion criteria to distill down the number of papers eligible for use. Inclusion criteria were: English only, articles had to report quantitative data, ultrasound had to be used, the focus had to be on soft tissue foreign bodies, sample size had to be greater than 10 patients, experience of ultrasonographer had to be stated, scans needed to be in 2 planes, and only studies looking at live human subjects were eligible. The analysis excluded ocular foreign bodies, deep tissue penetration, and respiratory foreign bodies. In determining sensitivity and specificity, the index test was either CT scan or surgical exploration of the wounds. In all, 17 studies met inclusion criteria and were included in the meta-analysis.

The Findings:

Overall sensitivity of ultrasound in identifying soft tissue foreign bodies was 72% and the specificity was 92%. Subgroup analysis found that radiolucent or wooden foreign bodies had a sensitivity and specificity of 96.7% and 84.2%, respectively. Notably, in the general adult emergency department setting, sensitivity and specificity were both 91%. The analysis was limited, however, by largely heterogenous studies. Some were in specialty settings such as pediatric emergency rooms, orthopedic emergency rooms, and in the inpatient setting. Additionally, significant bias was noted across studies, there was user dependency of ultrasound, and the fact that these studies did not use point of care ultrasound added to the heterogeneity of findings. Overall, the quality of these studies was low.

The Takeaway:

Further research is needed to verify the results found in this meta-analysis and to determine the optimal situations for using point of care ultrasound in identifying soft tissue foreign bodies, but the article demonstrated that it is a valuable tool for use in the emergency room setting given that it can be done quickly, the patient is not exposed to ionizing radiation, it is low cost, and ultrasound can be used in removal of foreign bodies.