Neuraxial Anesthesia Reduces Lymphatic Flow: Proof-of-Concept in First In-Human Study.

Dilation of lymphatic vessels may contribute to iatrogenic dissemination of cancer cells during surgery. We sought to determine whether neuraxial anesthesia reduces regional lymphatic flow. Using nuclear lymphoscintigraphy, 5 participants receiving spinal anesthesia for brachytherapy had lower extremity lymph flow at rest compared with flow under conditions of spinal anesthesia. Six limbs were analyzed. Four limbs were excluded because of failure to demonstrate lymph flow (1 patient, 2 limbs), colloid injection error (1 limb), and undiagnosed deep vein thrombosis (1 limb). All analyzed limbs showed reduced lymph flow washout from the pedal injection site (range 62%-100%) due to neuraxial anesthesia. Lymph flow was abolished in 3 limbs. We report proof-of-concept that neuraxial anesthesia reduces lymphatic flow through a likely mechanism of sympathectomy.