Background: Foreign bodies are sometimes overlooked in the initial evaluation of soft tissue wounds in the emergency room setting. The physical examination identifies foreign bodies that are superficial enough to be seen or palpated, while radiographs reveal those that are radio-opaque. If these two criteria are not met, however, the foreign body may remain undetected. These patients present later with long-standing pain in the area of penetration sometimes associated with localized tenderness.

Objectives: To assess the role of ultrasonography in the diagnosis and management of patients with a suspected retained foreign body.

Methods: Ultrasound was used in 21 patients with suspected retained foreign bodies and the diagnosis was positive in 19. Fifteen underwent a surgical exploration in which the ultrasound was used as an adjunctive modality either pre- or intraoperatively to assist in the localization of the foreign body.

Results: All procedures were successful. No postoperative complications were recorded at an average follow-up of 2 years. Three patients gradually became asymptomatic and were left untreated. One patient was lost to follow-up.

Conclusion: Sonography is an extremely effective tool for the late diagnosis of retained foreign bodies in the soft tissues. We suggest that its availability in the emergency room may decrease the rate of misdiagnosis and avoid these unfortunate cases, although this remains tc be proven.