What specialist should a patient with a 3x3mm echogenic (ultrasound) focus, likely a foreign body, under the skin surface on the sole of the foot be referred to for removal?

From the Guidelines

I strongly recommend referring the patient to a podiatrist or orthopedic surgeon for removal of the foreign body, as they have the expertise to safely extract embedded objects from the foot and prevent potential complications such as infection, chronic pain, or inflammatory reactions to the foreign material. The 3x3mm echogenic foci seen on imaging likely represents a foreign body that penetrated the skin when the patient stepped on an object. Even though it's not visible on external examination, ultrasound has detected its presence beneath the skin surface, with a reported sensitivity of 95% for the detection of foreign bodies 1. The specialist will likely use imaging guidance (ultrasound or fluoroscopy) during the procedure to precisely locate and remove the object, and may perform the removal under local anesthesia in an outpatient setting.

According to the American College of Radiology, ultrasound is the optimal imaging modality for detecting radiolucent foreign bodies, such as plastic or wood, and can provide precise localization of the foreign body 1. The specialist should be aware that the foreign body may be surrounded by a rim of hyperechogenicity, which can represent a soft tissue granulomatous reaction, and that ultrasound can also detect complications of foreign body infections such as cellulitis, myositis, abscesses, sinus tracts, and vascular or tendon injuries 1.

The patient should be advised to keep the area clean and monitor for signs of infection such as increasing pain, redness, swelling, or drainage until they can see the specialist. It is also important to note that the specialist may need to use additional imaging modalities, such as CT or MRI, to further evaluate the foreign body and surrounding tissue, especially if the foreign body is not visible on ultrasound or if there are concerns about deeper tissue involvement 1.

Key considerations for the specialist include:

• Using imaging guidance to precisely locate and remove the foreign body
• Performing the removal under local anesthesia in an outpatient setting
• Monitoring for signs of infection or other complications after the procedure
• Considering additional imaging modalities if necessary to evaluate the foreign body and surrounding tissue.

From the Research

Removal of Foreign Bodies

To remove the 3x3mm echogenic foci seen below the skin surface on the sole of the patient's foot, the following options can be considered:

• Referral to a primary care physician or an emergency medicine physician for initial evaluation and management, as suggested by 2
• Consultation with an orthopedic surgeon or a specialist in foot and ankle surgery, as mentioned in 3 and 4
• Use of imaging techniques such as ultrasonography, radiography, or computed tomography to localize the foreign body, as discussed in 5, 6, and 4

Considerations for Removal

Before removing the foreign body, the following factors should be considered:

• The risk of complications, such as chronic pain and neurovascular impairment, as mentioned in 2
• The type and location of the foreign body, as discussed in 3 and 6
• The use of adequate analgesia and anesthesia, as suggested by 2
• The potential need for antibiotic prophylaxis, as mentioned in 2

Imaging Techniques

The choice of imaging technique depends on the type and location of the foreign body:

• Ultrasonography is useful for detecting non-metallic foreign bodies, as mentioned in 5 and 4
• Radiography is useful for detecting metallic foreign bodies, as discussed in 6
• Computed tomography and magnetic resonance imaging can also be used to detect foreign bodies, as mentioned in 6