Femoral Artery Dissection after Adductor Canal Block

After an uneventful total knee arthroplasty under spinal anesthesia and ultrasound-guided continuous adductor canal block, the absence of distal pulses was noted in the operative leg. An arterial duplex scan (top image, panel A) demonstrated a femoral artery dissection flap (thin arrow) with a false lumen (thick arrow). Color Doppler demonstrated an absence of arterial flow distal to the dissection (top image, panel B; asterisk). During emergent thrombectomy and arterial repair, a puncture site of the Tuohy needle was noted on the femoral artery (thin arrow; bottom image, panel A), with perivascular hematoma (thick arrow; bottom image, panel A) and an intravascular thrombus (bottom image, panel B). The patient subsequently regained limb perfusion.

Inadvertent vascular puncture is a known complication of peripheral nerve blockade. The use of ultrasound guidance for peripheral nerve blockade improves safety and reduces the risk of vascular puncture.¹  The rate of vascular puncture after femoral nerve blockade is 1.1%;²  ultrasound-guided adductor canal block is considered safe, and vascular complications, including hematoma and pseudoaneurysm formation, appear to be rare.³ 

This image shows that vascular puncture during peripheral nerve blocks may be associated with important complications, and underscores the importance of routine surveillance for adverse vascular events.

Vascular puncture should prompt frequent assessment of limb perfusion, to avoid missing time-sensitive, limb-threatening complications, and should be considered in the differential diagnosis of limb ischemia after peripheral blocks, prompting emergent vascular consultation.