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Detection of Foreign Bodies in Soft Tissue – A PoCUS-Guided Approach

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Medical Student Clinical Pearl

Sophia Miao, CC4

MD Candidate, Class of 2021

Dalhousie University

 

Reviewed & Edited by Dr David Lewis (@e_med_doc)

All case histories are illustrative and not based on any individual.

 

Case Report

A 33-year-old woman presents to the ED with pain and swelling over the third digit of her right hand.  One week prior to this, she had shattered a jar and a small glass splinter lodged into her finger.  This was promptly removed at home, and the puncture wound healed without intervention.

She presented to the emergency room 7 days later with new pain and swelling surrounding the initial puncture wound.  There is no significant past medical history and most recent Td booster was given 2 years ago.  On examination, there was some mild erythema, swelling, and tenderness on palpation of the lateral aspect of the middle phalanx of the right hand.  She is otherwise well.  You wonder about the possibility of a retained foreign body.

 

PoCUS-Guided Approach to the Detection of Foreign Bodies in Soft Tissue

Foreign bodies in soft tissue are a common complaint in the emergency department, with open wounds comprising 5.7 million (or 4.5% of total) visits to the ED in 2010.[1]  Foreign bodies were found in up to 15% of wounds.[2]  If retained, complications of these include allergic reaction, inflammation, delayed wound healing, damage to adjacent tissue structures, neurovascular damage, tetanus, and infectious complications including cellulitis, necrotizing fasciitis, synovitis, and abscess formation.[3],[4]  Proper detection, and subsequent removal, of retained foreign bodies is therefore essential to evaluate the wound and prevent associated complications.

Diagnosis of a retained FB requires a high index of suspicion.  Clinical suspicion should be raised when there is a compelling history and physical exam.  The latter may include signs of inflammation and/or infection, including warmth, swelling, erythema, tenderness, abscess formation, and discharging wound).[5],[6]

Conventional radiography is known to commonly miss radiolucent materials such as wood and plastic.  It has been shown that plain radiographs have only a 7.4% sensitivity in the detection of wood foreign bodies.5  Remarkably, even glass – a radiopaque material – has been demonstrated to have been missed in up to 35% of x-ray film studies.[7]  There is increasingly compelling evidence for the clinical usefulness and accuracy of bedside ultrasonography in the detection of soft-tissue foreign bodies.  It has been shown to have a specificity of 92% (95% CI = 88%-95%) and sensitivity ranging from 83.3% to 100%.[8],[9]

PoCUS Technique

Probe selection: the use of a high-frequency ultrasound probe is recommended.  This allows for greater axial resolution at the expense of less penetration, which is suitable for the detection of small foreign bodies, as they typically lodge in superficial tissues.[10]

If the wound is open, a transparent covering such as a Tegaderm or probe cover can be used to cover either the wound or probe before scanning.[11]

Medium: standard technique for assessment of soft-tissue structures by ultrasound involves the use of a standoff pad or gel mound.  However, this is not always possible due to the irregular curvature of extremities such as fingers and feet, which may result in poor contact between the probe and skin, decreased field of view, and patient discomfort.  A water-bath technique can circumvent this and has been shown to be superior in such cases.[12]

Method: the area of interest should be scanned in both longitudinal and transverse planes.  Foreign bodies are best detected when the transducer aligns with the longitudinal axis of the foreign body, and therefore revealing the span of the object.[13]  As foreign bodies tend to embed less than 2 cm below the surface of the skin, the depth of field should remain superficial in order to avoid false positives.

US Probe: Ultrasound Water Bath for Distal Extremity Evaluation

 

Findings

Ultrasonography and plain film findings of foreign bodies in soft tissue are summarized in the table below.

Table 1. Ultrasound and x-ray findings of foreign bodies.6,[14],[15],[16]

Material Ultrasound findings X-ray findings
Wood Hyperechoic; may become isoechoic with surrounding tissue as it denatures over time

Posterior acoustic shadowing

 Radiolucent, often undetectable
Glass Hyperechoic, bright

Posterior acoustic shadowing

± Posterior comet tail reverberation, diffuse beam scattering

 Radiopaque
Plastic Hyperechoic

Posterior acoustic shadowing

 Radiolucent, often undetectable
Metal Hyperechoic, bright

Posterior acoustic shadowing

± Posterior comet tail reverberation

 Radiopaque

 

Foreign bodies may also display a straight or regular contour.6

 

Image 1 – Wood splinter in volar aspect digit, mildly hyperechoic, surrounding hypoechoic halo, irregular acoustic shadowing

Image 2 – Plastic FB, within tendon sheath, volar aspect digit, brightly hyperechoic, long axis

Image 3 – Plastic FB, within tendon sheath, volar aspect digit, brightly hyperechoic, short axis

 

Image 4 – Glass FB – brightly echogenic, posterior reverberation, FB long axis

 

Image 5 – Metal FB – brightly echogenic, posterior reverberation, FB long axis

 

 

It is important to note that the acoustic shadowing may be complete or partial, as this is dependent on the angle of sonography and foreign body material.[17]  It is also possible to see a hypoechoic halo around the FB, which may be suggest edema, abscess formation, granulation tissue, or other inflammatory process.[18]  As the inflammatory reaction develops, the halo effect becomes more apparent; therefore the foreign body is therefore best visualized by PoCUS several days after the initial injury.6

PoCUS-Guided Foreign Body Removal

There are several options for removal of a foreign body with PoCUS:[19]

  1. Needle localization. Once the foreign body has been identified on PoCUS, a hollow injection needle can be inserted under ultrasound guidance and local anesthetic is delivered through this.  This can be done in either the transverse or longitudinal plane.  The ultrasound probe is then removed, and an incision is made along the needle.  Through the incision site, tweezers or forceps can be used to remove the foreign body.
  2. Real-time ultrasound-guided extraction. This technique is similar to the needle localization method. However, rather than removing the transducer following the needle insertion, the entire procedure is done under direct ultrasound visualization.  The probe is held in the longitudinal plane to visualize both the forceps and the foreign body during the extraction process.

 

There is a risk of obscuring the view of the foreign body on ultrasound with air as a result of the incision itself or through anesthetic delivery.  Saline may be used to irrigate and therefore mitigate the issue.19

The patient’s tetanus status should be verified and updated, if required.  Antibiotic therapy may also be provided, should the risk of infection justify it.

Limitations

There is the possibility of false positives.  Foreign bodies must be differentiated from other hyperechoic body structures, including ossified cartilage, sesamoid bones, scar tissue, gas bubbles, and intermuscular fascia.14  Visualization is therefore important in both longitudinal and transverse planes, as well as comparison with the opposite side.  Acoustic shadowing, hypoechoic halo, and posterior comet tails, if present, can also be indicative of a FB rather than organic body tissue.

Traumatic air injection as a result of penetrating injury can create a scatter artifact on ultrasound, which can be misinterpreted as an acoustic shadow associated with a foreign body.  To differentiate this from a true acoustic shadow, pressure may be applied through the transducer to displace the scatter artifact.6

As is commonplace with all emergency ultrasonography, limitations also include the technical skill of the operator.[20]  A foreign body may also be too small to be detectable by ultrasound.  It is therefore important to remember that a negative scan does not necessarily rule out the possibility of a retained foreign body, and the history and physical examination must be considered in conjunction with the ultrasound findings.

 

 

References

[1] National Center for Health Statistics. Emergency Department Visits. Available from: http://www.cdc.gov/nchs/fastats/emergency-department.htm.

[2] Steele MT, Tran LV, Watson WA, Muelleman RL. Retained glass foreign bodies in wounds: predictive value of wound characteristics, patient perception, and wound exploration. Am J Emerg Med. 1998 Nov;16(7):627-30. DOI: 10.1016/s0735-6757(98)90161-9. PMID: 9827733.

[3] Skinner EJ, Morrison CA. Wound Foreign Body Removal. In:StatPearls. Treasure Island (FL): StatPearls Publishing; 2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK554447/.

[4] Ebrahimi A, Radmanesh M, Rabiei S, Kavoussi H. Surgical removal of neglected soft tissue foreign bodies by needle-guided technique. Iran J Otorhinolaryngol. 2013 Winter;25(70):29-36. PMID: 24303416; PMCID: PMC3846242.

[5] Levine MR, Gorman SM, Young CF, Courtney DM. Clinical characteristics and management of wound foreign bodies in the ED. Am J Emerg Med. 2008 Oct;26(8):918-22. DOI: 10.1016/j.ajem.2007.11.026. PMID: 18926353.

[6] Atkinson P, Bowra J, Harris T, Jarman B, Lewis D. Point of Care Ultrasound for Emergency Medicine and Resuscitation. Oxford, United Kingdom: Oxford University Press; 2019. DOI: 10.1093/med/9780198777540.001.0001.

[7] Kaiser, C. William MD; Slowick, Timothy MBA; Spurling, Kathleen Pfeifer RN, JD; Friedman, Sissie MA. Retained Foreign Bodies, The Journal of Trauma: Injury, Infection, and Critical Care: July 1997 – Volume 43 – Issue 1 – p 107-111.

[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. 2015 Jul;22(7):777-87. DOI: 10.1111/acem.12714. Epub 2015 Jun 25. PMID: 26111545.

[9] Atkinson P, Madan R, Kendall R, Fraser J, Lewis D. Detection of soft tissue foreign bodies by nurse practitioner-performed ultrasound. Crit Ultrasound J. 2014 Jan 29;6(1):2. DOI: 10.1186/2036-7902-6-2. PMID: 24476553; PMCID: PMC3922659.

[10] Dean AJ, Gronczewski CA, Costantino TG. Technique for emergency medicine bedside ultrasound identification of a radiolucent foreign body. The Journal of Emergency Medicine. 2003;24(3):303–8. DOI: 10.1016/S0736-4679(02)00765-5.

[11] Chen KC, Lin AC, Chong CF, Wang TL. An overview of point-of-care ultrasound for soft tissue and musculoskeletal applications in the emergency department. J Intensive Care. 2016 Aug 15;4:55. DOI: 10.1186/s40560-016-0173-0. PMID: 27529031; PMCID: PMC4983782.

[12] Krishnamurthy R, Yoo JH, Thapa M, Callahan MJ. Water-bath method for sonographic evaluation of superficial structures of the extremities in children. Pediatr Radiol. 2013 Mar;43 Suppl 1:S41-7. DOI: 10.1007/s00247-012-2592-y. Epub 2013 Mar 12. PMID: 23478918.

[13] Rooks VJ, Shiels WE 3rd, Murakami JW. Soft tissue foreign bodies: A training manual for sonographic diagnosis and guided removal. J Clin Ultrasound. 2020 Jul;48(6):330-336. DOI: 10.1002/jcu.22856. Epub 2020 May 8. PMID: 32385865.

[14] Mohammadi A, Ghasemi-Rad M, Khodabakhsh M. Non-opaque soft tissue foreign body: sonographic findings. BMC Med Imaging. 2011 Apr 10;11:9. DOI: 10.1186/1471-2342-11-9. PMID: 21477360; PMCID: PMC3079678.

[15] Lewis D, Jivraj A, Atkinson P, Jarman R. My patient is injured: identifying foreign bodies with ultrasound. Ultrasound. 2015 Aug;23(3):174-80. DOI: 10.1177/1742271X15579950. Epub 2015 Mar 26. PMID: 27433254; PMCID: PMC4760591.

[16] Campbell EA, Wilbert CD. Foreign Body Imaging. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470294/.

[17] Anderson MA, Newmeyer WL 3rd, Kilgore ES Jr. Diagnosis and treatment of retained foreign bodies in the hand. Am J Surg. 1982 Jul;144(1):63-7. DOI: 10.1016/0002-9610(82)90603-1. PMID: 7091533.

[18] Little CM, Parker MG, Callowich MC, Sartori JC. The ultrasonic detection of soft tissue foreign bodies. Invest Radiol. 1986 Mar;21(3):275-7. DOI: 10.1097/00004424-198603000-00014. PMID: 3514541.

[19] Paziana K, Fields JM, Rotte M, Au A, Ku B. Soft tissue foreign body removal technique using portable ultrasonography. Wilderness Environ Med. 2012 Dec;23(4):343-8. DOI: 10.1016/j.wem.2012.04.006. Epub 2012 Jul 25. PMID: 22835803.

[20] Pinto A, Pinto F, Faggian A, Rubini G, Caranci F, Macarini L, Genovese EA, Brunese L. Sources of error in emergency ultrasonography. Crit Ultrasound J. 2013 Jul 15;5 Suppl 1(Suppl 1):S1. DOI: 10.1186/2036-7902-5-S1-S1. Epub 2013 Jul 15. PMID: 23902656; PMCID: PMC3711733.

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“The Mother’s Kiss”

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A Tool in Nasal Foreign Body Removal in Pediatric Patients

Melanie Johnston, PGY2 iFMEM Dalhousie University Saint John

Reviewed by Dr. Mandy Peach

 

Introduction:

The highest incidence of nasal foreign bodies is in pediatric patients, ages 2-5.1 The removal of nasal foreign bodies in the emergency department can be challenging.

The most common objects removed are beads, nuts, chalk, eraser heads, pebbles, and other small objects.1,2 While most nasal foreign bodies are benign, some objects can cause severe damage and need to be urgently removed.

The diagnosis of nasal foreign may be obvious as the caregiver may have witnessed the event and present acutely. Others may have delayed presentations of weeks-months after the child develops symptoms of nasal irritation/infection from the retained foreign body. In general, organic foreign bodies (flowers, plants, bugs) tend to be more irritating to the nasal mucosa and cause symptoms much earlier.2

 

Details on history and physical exam findings that should raise suspicion of a potential nasal foreign body in a paediatric patient include:

  • Witnessed insertion of foreign body
  • Unilateral foul-smelling purulent discharge
  • Mucosal erosions/ulceration

  • Unilateral epistaxis

  • Headache focused on the same side as the foreign body
  • Nasal obstruction
  • Mouth breathing2

 

Nasal foreign bodies have the potential to dislodge posteriorly and aspirate.1 Consider aspirated FB if new wheeze/cough/shortness of breath in a child with suspected intranasal FB and be prepared for a precipitous change in the airway. 6 

 

Nasal foreign bodies are most commonly located on the floor of the nasal passage under the inferior turbinate, or superiorly  in front of the middle turbinate.2

Foreign bodies are most frequently located on the right side, due to the right handed dominance of most children.2

Figure 1. Anatomy of the nose.3

 

Examination:

Ensure good lighting to be able to visualize the canal. Place the patient in a sniffing position with caregiver assistance (they may have to firmly hold child for cooperation). Suction should be readily available for nasal discharge and to aid in visualization. Nasal speculum can be used to aid visualization of the canal. Visualization of the foreign body confirms the diagnosis.

 

Figure 2. Marble nasal foreign body in pediatric patient.4

 

ENT referral is warranted if:


– Foreign body suspected, but unable to visualize by anterior rhinoscopy
– Impacted foreign body with marked inflammation (eg button batteries)
– Penetrating foreign body
– Any foreign body that cannot be removed due to poor cooperation, bleeding, or limited instrumentation2

 

Foreign Body Removal Options:

There are a number of techniques for nasal foreign body removal in the Emergency Department: alligator forceps, suction, balloon catheters, cyanoacrylate glue.2 Depending on the patient, these methods can be technically challenging if the patient is uncooperative, and may require the use of procedural sedation. A less invasive alternative for children not willing to cooperate with manipulation in the nasal canal is the Mothers’ Kiss.

 

Mothers’ Kiss Technique:

This technique was first described in the 1960s by a general practitioner in New Jersey and uses positive pressure to mobilize the foreign body from the nasal passage.1 It is effective in approximately 60% of attempts5, and generally most effective for smooth/soft foreign bodies that totally occlude the anterior nasal cavity.2 Even when not successful, it may improve visibility of the foreign body. Theoretical risks include barotrauma to both the tympanic membranes or pneumothorax, but these complications have never been reported.5 The pressure used by the caregiver to attempt expulsion of the foreign body is equivalent to that of a sneeze, approximately 60mmHg.1 The main danger in removing a foreign body from the nose is the risk of aspiration.

Procedure:5
1) Instruct the caregiver to place their mouth over the childs’ open mouth, forming a firm seal (similar to mouth-to-mouth resuscitation).
2) Next, occlude the unaffected nostril with a finger
3) The caregiver should blow until they feel resistance (caused by the closure of the childs’ glottis), then they should deliver a short puff of air into the childs’ mouth
4) The puff of air travels through the nasopharynx, and if successful results in the expulsion of the foreign body
5) If unsuccessful, the procedure can be repeated a number of times

Figure 3: Caregiver performing “Mother’s Kiss”. Shows occlusion of unaffected nare,
with seal formed around childs’ mouth.

 

 

If the caregiver is unable to perform the procedure, the approach can be recreated with a bag-valve-mask as the positive pressure source, ensuring the mask covers only the childs’ mouth.

Figure 4: Positive Pressure Ventilation with Bag-Valve-Mask.6

 

 

For a visual review of these techniques, please refer to the following videos:

“Mother’s Kiss”

 Positive Pressure Ventilation

 

Bottom Line:

Nasal foreign bodies are a common occurrence in the paediatric population. Their removal in the Emergency Department can be challenging as the patient may be fearful and non-cooperative. While there are a number of methods for removal of nasal foreign bodies, the “Mothers’ Kiss” technique provides a relatively non-invasive alternative. It has been shown to be effective in removal of 60% of nasal foreign bodies, and is most effective if foreign bodies are smooth and located in the anterior nasal cavity. If the caregiver is unable to perform the procedure, the approach can be recreated with BVM as the positive pressure source. The risks of this technique are minimal, and even when unsuccessful, can assist in improving the visualization of the nasal foreign body.

 

References:

  1. Cook, S., Burton, M., & Glasziou, P. (2012). Efficacy and safety of the “mother’s kiss” technique: a systematic review of case reports and case series. CMAJ : Canadian Medical Association journal = journal de l’Association medicale canadienne, 184(17), E904–E912. https://doi.org/10.1503/cmaj.111864

  2. Isaacson, G., Ojo, A. (2020). Diagnosis and management of intranasal foreign bodies. Up to Date. Retrieved from https://www.uptodate.com/contents/diagnosis-and-management-of-intranasal-foreign-bodies.

  3. Le, P. (2020). Anatomy, Head and Neck, Nasal Concha. Retrieved from: https://www.statpearls.com/ArticleLibrary/viewarticle/32550

  4. Nose-Foreign Body Nose, Dr Vaishali Sangole. Retrieved Oct 31,2020 from: http://vaishalisangole.com/NOSE_Foreign.html

  5. Glasziou, P., Bennett, J. (2013). Mothers’ kiss for nasal foreign bodies. Australian Family Physician, 42(5): https://www.racgp.org.au/afp/2013/may/mothers-kiss/.

  6. Thoreckzo. (2017). Foreign Bodies in the Head and Neck. Pediatric Emergency Playbook. Retrieved from: https://pemplaybook.org/podcast/foreign-bodies-in-the-head-and-neck/

  7. Pretel, M. Removing object from child’s nose using the kiss technique. Youtube- retrieved from: https://www.youtube.com/watch?v=RR3SxICqdAY.

  8. Dudas, R. Nasal foreign body removal. Youtube- retrieved from: https://www.youtube.com/watch?v=PacvHiJFhNA.

 

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Wooden Splinter detected by PoCUS

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Approach to wooden foreign bodies in the hand using Point of Care Ultrasound.

Medical Student Clinical Pearl

Jefferson Hayre, Med II

Dalhousie Medicine New Brunswick

Detection and removal of a wooden foreign body is often a challenge and time consuming procedure. Failure to detect and remove, and subsequent retention in the soft tissue leads to increased morbidity through infection, pain, multiple clinical visits, and surgery.

Wood is radiolucent and therefore generally goes undetected in plain radiography. One study showed that only 15% of wooden foreign bodies were visible on plain radiography compared to metal (100%) and glass (96%).

Some studies of ultrasound has shown sensitivies of >89% and specificities of >93% in detection of wooden foreign bodies in soft tissue.

We were able to use ultrasound to detect a wooden foreign body (figure 1), as wells as it’s size (figure 2) and orientation. On ultrasound wooden foreign bodies appear as a hyperechoic foci with acoustical shadowing and a hypoechoic halo, usually only seen after 24 hours due to the inflammatory response.

fb2

Figure 1 – Wooden foreign body in the hand. Note the hyperechoic line and the acoustic shadow below.

fb1

Figure 2 – Measurement of a wooden foreign body in the hand. Using the measuring tools on the ultrasound machine we successfully measured the wooden foreign body to be 85mm.

In addition to removal of the foreign body, the patient’s tetanus immunization status must be reviewed. Immunization should be delivered to those patients who need it.

The wound should be cleaned with an iodophor or other antiseptic solution, and any jagged edges of the wound should be trimmed.

There is currently no solid evidence on the efficacy of prophylactic antibiotics in puncture wounds.

Further Reading on PoCUS for FB – Here

References:

Anderson MA, Newmeyer WL 3rd, Kilgore ES Jr. Diagnosis and treatment of retained foreign bodies in the hand. Am J Surg. 1982 Jul;144(1):63-7.

Baddour LM. Overview of puncture wounds. In: UpToDate, Sexton DJ (Ed), UpToDate, Waltham, MA. (Accessed on May 1, 2015.)

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