What is the best approach for diagnosing and managing a patient with a suspected glass fragment in their hand, particularly using ultrasound?

Ultrasound for Suspected Glass Foreign Body in Hand

For suspected glass fragments in the hand, start with plain radiographs as the primary imaging modality, not ultrasound, because glass is radiodense and visible on x-rays in the vast majority of cases. 1

Initial Diagnostic Approach

Plain Radiographs First

• Obtain plain radiographs immediately for any patient with a puncture wound or suspected glass foreign body in the hand. 1
• Glass is inconsistently visible radiographically only when fragments are very small or obscured by adjacent bone structures, but the vast majority of glass foreign bodies are detected on plain films. 1
• Radiographs detected glass in 25 of 26 patients (96%) in one series, and almost all glass foreign bodies can be visualized with standard or high-resolution techniques. 2
• Plain radiographs are low cost, accessible, and highly effective—objections to obtaining them should be minimal given the adverse consequences of retained foreign bodies. 3

When to Use Ultrasound

Ultrasound is the optimal imaging modality for radiolucent foreign bodies (plastic, wood), not glass. 1

However, ultrasound has specific utility in glass injuries:

• Use ultrasound for precise localization of glass fragments already detected on radiographs to guide removal. 1
• Consider ultrasound when radiographs are negative but clinical suspicion remains high (persistent foreign body sensation, pain, or wound that won't heal). 4
• Ultrasound is valuable for detecting soft-tissue fluid collections and evaluating for concomitant soft-tissue infections that may develop around retained glass. 1

Limitations of Ultrasound

• Ultrasound can underestimate disease extent and has limited visualization of deeper structures. 1
• Bone and gas hinder ultrasound evaluation. 1
• For glass specifically, radiography remains superior for initial detection. 1

Clinical Management Algorithm

Step 1: Clinical Evaluation

• Wounds with foreign body sensation, persistent pain, or visible glass should be evaluated with imaging. 4
• Superficial wounds (no deeper than subcutaneous fat) that can be adequately explored clinically may not require routine x-rays, as clinically undetected foreign bodies occurred in only 1.5% of such wounds. 5
• Deeper wounds or those that cannot be adequately explored require imaging. 5

Step 2: Imaging Selection

• Obtain plain radiographs for all suspected glass injuries except the most superficial, easily explorable wounds. 3, 5
• Consider CT without IV contrast if precise localization is needed for surgical planning, as CT allows precise foreign body localization. 1
• Reserve ultrasound for guiding removal of known fragments or when radiographs are negative despite high clinical suspicion. 1

Step 3: Removal Indications

• Remove glass foreign bodies when there is pain, foreign body sensation, or presence of pigmenting materials. 4
• Set a time limit for exploration and have a plan for referral if removal is unsuccessful. 4
• Retained glass can cause infection, delayed healing, persistent pain, and late injury from migration. 3

Critical Pitfalls to Avoid

• Do not skip radiographs in favor of ultrasound for glass injuries—this reverses the appropriate imaging hierarchy. 1
• Glass foreign bodies are frequently overlooked when examination is limited to inspection and probing without radiographic evaluation. 2
• If a patient presents with an infected wound in the hand, always consider a retained foreign body and obtain imaging. 4
• Wounds containing organic material or those that are dirty require plain water irrigation, complete fragment removal, and consideration of infection risk. 4

Infection Risk Management

• High-risk wounds include those with organic foreign bodies or dirty wounds. 4
• Most glass injuries do not require antibiotic prophylaxis unless the wound is infected or contaminated. 4
• Ensure tetanus prophylaxis is current (within 10 years). 4