Locating and removing a foreign body is a challenge that emergency physicians commonly encounter. Patients presenting with an open wound should always raise suspicion for a potentially embedded foreign body . While ultrasonography can be used to diagnose the presence of soft tissue foreign bodies, its success in several studies has been variable [2, 4–6]. The current indications by the American College of Emergency Physicians (ACEP) for obtaining a focused emergency soft tissue ultrasound include the evaluation for soft tissue infection, foreign bodies, and cutaneous masses . Currently plain radiographs are more accessible, easier to interpret by nonradiologists, and are not as operator-dependent as ultrasonography. However, while metal and glass are radio-opaque and usually apparent on plain radiographs, plastic and wooden foreign bodies are nearly always missed . In addition, while radiographs may be more accessible and easily interpreted, they are generally less useful in the removal of a foreign body.
Soft tissue foreign bodies may demonstrate a variety of sonographic patterns depending on several factors including composition, size, and length of time embedded. Common materials such as wood, glass, metal, plastic, and gravel will generally appear hyperechoic, with posterior shadowing. Foreign bodies retained for longer than 24 h are frequently surrounded by a hypoechoic “halo” due to surrounding edema, pus, or granulation tissue .
Whether radio-opaque or radiolucent, once the foreign body has been identified, the next and often more difficult task is to localize and remove it. Unsuccessful removal of soft tissue foreign bodies may result in further tissue injury, infection, and problems with wound healing . In this case report, the surrounding area was anesthetized, and a 22-gauge finder needle was inserted under ultrasound-guidance adjacent to the foreign body. Ultrasonography may be used to identify a soft tissue foreign body, but perhaps the more useful application in the emergency department is the localization and removal of it.