Correct answer to Q2 is: Foreign body penetrating into the flexor tendon
Additional discussion
US examination using a 6-15 MHz linear probe showed a 19-mm-long echogenic structure extending into the flexor tendon of the left fourth finger at the level of the distal metacarpal bone, locking the tendon in place. There is a hypoechoic rim around the tendon associated with thickened synovium (white arrow). Slight posterior shadowing of the foreign body is noted (black arrows).
Surgical exploration was performed without complications with successful retrieval of a 2 cm long wood splinter. The procedure yielded a good result with immediate return to full range of motion of the finger.
Hand injuries are among the most common causes of emergency room visits in clinical practice and they are frequently associated with the presence of a retained foreign body. Foreign bodies are often overlooked at initial examination and can lead to a wide range of complications including infection, neurological deficits or tendon lacerations (1,2,3).
While wood slivers are among the most commonly reported foreign bodies, their detection remains exceptionally challenging, because plain radiography fails to visualize them in the majority of cases (1,4). The correct diagnosis becomes even more difficult when patients present without a reported history of penetrating injury.
Ultrasound is the modality of choice for evaluation of soft tissues, aiding not only in the detection of foreign materials, but also in providing their more precise localization and evaluating concomitant complications. It is especially useful in cases of radiolucent materials, which can otherwise remain undetected (2,3). Wood splinters typically appear as linear echogenic structures with pronounced acoustic shadowing (3).
Conclusion
Retained wooden foreign bodies can be easily missed on clinical evaluation and radiography. US allows accurate detection of radiolucent soft-tissue foreign bodies and aids in assessment of their associated complications.
Conflicts of Interest:
No conflict of interest.
References
- Anderson MA, Newmeyer WL 3rd, Kilgore ES. Diagnosis and treatment of retained foreign bodies in the hand. Am J Surg 1982; 144:63– 67
- Boyse TD, Fessell DP, Jacobson JA, Lin J, van Holsbeeck MT, Hayes CW. US of soft-tissue foreign bodies and associated complications with surgical correlation. Radiographics 2001; 21:1251–1256
- Jacobson JA, Powell A, Craig JG, Bouffard JA, van Holsbeeck MT. Wooden foreign bodies in soft tissue: detection at US. Radiology 1998; 206:45– 48.
- Peterson JJ, Bancroft LW, Kransdorf MJ. Wooden foreign bodies: imaging appearance. AJR Am J Roentgenol 2002; 178(3):557–562
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