When using a handheld Doppler to assess tibial vessels in the ER for a patient with trauma to the lower third of the leg requiring a flap, which tibial vessel should be followed up on?

Vascular Assessment in Lower Leg Trauma: Vessel Selection for Handheld Doppler Evaluation

When using a handheld Doppler to assess tibial vessels in the emergency room for a patient with trauma to the lower third of the leg requiring a flap, the posterior tibial artery should be followed up. 1

Rationale for Posterior Tibial Artery Assessment

The posterior tibial artery is the preferred vessel to assess with handheld Doppler in the emergency room setting for several important reasons:

• It provides the most reliable and accessible signal for vascular assessment in trauma patients
• It has 87% sensitivity and 97% specificity for diagnosing vascular injury when used for ABI calculation 1
• It is critical for flap viability in lower leg reconstruction, particularly for patients requiring flaps in the lower third of the leg

Proper Technique for Posterior Tibial Artery Assessment

When assessing the posterior tibial artery with handheld Doppler:

1. Position the patient supine in a relaxed position
2. Apply Doppler gel over the sensor
3. Use an 8-10 MHz Doppler probe positioned at a 45-60° angle to the skin surface
4. Locate the posterior tibial artery behind and below the medial malleolus
5. Move the probe until the clearest signal is heard 1

Clinical Significance for Flap Planning

The posterior tibial artery assessment is particularly important for flap planning because:

• Perforators from the posterior tibial artery are crucial for many lower leg flaps, especially in the distal third of the leg 2
• A considerable number of perforators are located 70-140 mm superior to the medial malleolus 2
• For ABI measurement, apply a cuff 2 cm above the superior aspect of the medial malleolus 1

Warning Signs During Assessment

Pay particular attention to the following warning signs that warrant immediate further investigation:

• ABI less than 0.9
• Absence of audible Doppler signal in the posterior tibial artery
• Asymmetry between injured and uninjured limbs
• Weak or monophasic signals suggesting arterial compromise 1

Clinical Implications for Flap Success

The number of patent tibial vessels significantly impacts limb salvage outcomes:

• Patients with only 0-1 patent tibial vessels have significantly higher rates of failed observation (44%) compared to those with 2-3 patent vessels (8%) 3
• The amputation rate is inversely related to the number of open tibial vessels 3
• Careful assessment of the posterior tibial artery is essential for determining the viability of local flap options versus the need for free tissue transfer 4

In cases with significant swelling or suspected complex vascular injury, handheld Doppler assessment may have limitations, and CT angiography may be necessary for complete assessment 1.