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Foreign Body

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Authors

Daniella M Santiago Haddock, MD, FAAEM, FAAP
Assistant Professor
Department of Emergency Medicine
St Luke’s Episcopal Medical Center
Ponce Health Sciences University

Eddie G. Rodríguez Aquino, MD
Emergency Ultrasound Director
Department of Emergency Medicine
St. Luke’s Episcopal Medical Center
Ponce Health Sciences University

Summary

  • Traumatic injuries with possible foreign bodies are common in the Emergency Department (ED)
  • Bedside ultrasound provides a fast, portable modality for evaluating suspected foreign bodies, without risk of radiation
  • Bedside ultrasound can help identify non-radiopaque foreign bodies missed on plain films
  • It can be used as an adjunct for direct visualization and real-time guidance during removal
Soft Tissue US Foriegn Body Glass
Soft tissue ultrasound showing a linear, echogenic focus which is known to be glass[1]Case courtesy of Dr Maulik S Patel, Radiopaedia.org, rID: 53273
Soft Tissue US Foriegn Body metal with artifact
Soft tissue ultrasound showing a small focus superficially which is known to be a metal fragment. Note the comet tail artifact.[2]Image courtesy of Stephen Alerhand, emdocs.net, “Ultrasound for Retained Radiolucent Foreign Body in Soft Tissue”
Soft Tissue US Foriegn Body splinter
Soft tissue ultrasound showing two linear echogenic foci known to be wooden splinters in the flexor digitorum superficialis muscle belly.[3]Case courtesy of Dr Maulik S Patel, Radiopaedia.org, rID: 51536
This video demonstrates a hyperechoic, irregular soft tissue foreign body. This was known to be a bullet in the plantar surface of the foot.
This video demonstrates a hyperechoic foreign body in the upper arm (needle) with removal.

Introduction

  • Traumatic injuries and wounds are one of the top complaints prompting ED visits.
  • For ED providers, assessing for retained foreign bodies has become an integral part of the evaluation and management of some of these injuries.
  • Foreign bodies that go undetected can lead to complications such as inflammation and infection [4]Ultrasound-Guided Procedures. ” Clinical Emergency Radiology, by J. Christian Fox, Cambridge University Press; 2017., and are a common cause for medical malpractice lawsuits against emergency physicians.[5]Schlager D. Ultrasound detection of foreign bodies and procedure guidance. Emerg Med Clin North Am. 1997;15(4):895-912.[6]Pfaff JA, Moore GP. Reducing risk in emergency department wound management. Emerg Med Clin North Am. 2007;25(1):189-201.
  • Bedside ultrasound can help evaluate for and identify foreign bodies that are not radiopaque such as plastic, organic material, and wood.[7]Anderson MA, Newmeyer WL. Diagnosis and treatment of retained for- eign bodies in the hand. Am J Surg. 1982;144(1).[8]Davis J, Czerniski B, Au A, Adhikari S, Farrell I, Fields JM. Diagnostic accuracy of ultrasonography in retained soft tissue foreign bodies: A systematic review and meta-analysis. Acad Emerg Med. … Continue reading
  • This makes ultrasound a useful adjunct when plain films fail to identify foreign bodies, without the potential risks (e.g. radiation exposure) and cost of other imaging modalities such as CT scan and MRI.

Advantages & Disadvantages

  • Advantages
    • Can identify soft tissue foreign bodies that are not radiopaque, or too small to be readily identified by plain films [9]Davis J, Czerniski B, Au A, Adhikari S, Farrell I, Fields JM. Diagnostic accuracy of ultrasonography in retained soft tissue foreign bodies: A systematic review and meta-analysis. Acad Emerg Med. … Continue reading
    • Helps evaluate for related complications such as abscess formation, hematoma, cellulitis [10]Blankenship RB, Baker T. Imaging modalities in wounds and superficial skin infections. Emerg Med Clin North Am. 2007;25(1):223-234.
    • No need to transport patient- can be done at bedside
    • Can be used for real-time guidance of foreign body removal
  • Disadvantages
    • May be challenging on complex or stellate soft tissue injuries or significant trauma

Indications

  • Suspected foreign body
  • Deep lacerations
  • Puncture wounds
  • Recurrent soft tissue infections in same location
  • Soft tissue infection with history of IV drug abuse
  • Identifying foreign body location, depth, size prior to removal
Video demonstrating the importance of having the probe parallel to the foreign body. The user in this video is changing the angle of the needle to probe from parallel to oblique and back.

Procedure

  • Probe: High frequency 5-10 MHz linear transducer [11]Scruggs W. Ma and Mateer’s Emergency Ultrasound. Ma EOJ, ed. Published online 2021.; the higher the frequency, the more detailed the imaging
    • Place the transducer perpendicular to the affected skin surface or suspected area where the foreign body is located
    • Proceed to scan the area in different planes (long axis and short axis views)
  • Scan slowly throughout area, since small foreign bodies can be missed easily
    • Look for shadowing artifact in multiple planes as well
    • Depending on mechanism of injury, there may be multiple foreign bodies
  • Foreign bodies will appear as hyperechoic structure with posterior shadowing
  • Once the foreign body is located, adjust the depth so the foreign body’s location and perimeter is visualized in at least two-thirds of the total screen area
Soft Tissue US Foriegn Body Wood Long Axis
Wooden foreign body in long axis.
Soft Tissue US Foriegn Body Wood Short Axis
Wooden foreign body in short axis.
  • Move the probe to center the foreign body in the screen
  • Adjust the gain in order to have a complete view of adjacent tissues and structures
  • Take clips of the foreign body in both longitudinal and transverse planes
  • Use color flow to detect possible vessels in the surrounding area
  • Once visualized, determine whether foreign body removal is indicated
  • Foreign bodies with smooth surfaces such as metal and glass may have reverberations as well as acoustic shadow [12]Hiremath R, Reddy H, Ibrahim J, Haritha CH, Shah RS. Soft tissue foreign body: Utility of High Resolution Ultrasonography. J Clin Diagn Res. 2017;11(7):TC14-TC16.
Soft Tissue US Foriegn Body Needle Long Axis
Metallic foreign body in short axis.
Soft Tissue US Foriegn Body Wood Short Axis
Metallic foreign body in short axis.
This video demonstrates a round hyperechoic foreign body in the soft tissue. Note the posterior acoustic shadowing.
This video demonstrates a palm thorn through the anterior ankle into joint. Note the foreign body is highly mobile with transducer pressure. Also note the hypoechoic fluid around the foreign body.

Potential Complications

  • Discomfort secondary to cold gel
  • Worsening patient pain due to probe pressure over affected area

Contraindications

  • Absolute Contraindications
    • No absolute contraindication for performing bedside ultrasound
  • Relative Contraindications
    • Uncooperative patient
    • Marked deformity of overlying area that alters anatomical landmarks

Pearls & Pitfalls

  • Results remain user-dependent
  • Foreign bodies that are embedded in deeper soft tissues may be missed
  • Subcutaneous air within soft tissue can mimic a foreign body and possibly alter sonographic characteristics of any retained foreign bodies [13]Jacobson J. Basic Pathology Concepts. In: Fundamentals of Musculoskeletal Ultrasound. Elsevier – Health Sciences Division; 2018:31-37.
  • Scan in both longitudinal and transverse (long and short axis) planes to fully visualize foreign body
  • Use skin marker to pinpoint location of foreign body as best as possible if attempting removal
  • Abundant use of gel with minimal probe pressure in order to avoid compressing and missing superficial fragments

References

References[+]