Single-needle lateral approach for lumbar sympathetic block.

During the past 5 years, we have used a single-needle lateral approach to lumbar sympathetic block. With the patient prone, a 22-gauge, 14-cm lumbar-puncture needle is inserted at a point 12.5 cm lateral to the spine of the 4th lumbar vertebra at a 35 to 40 degrees angle to the skin. When the needle is placed opposite the anterolateral surface of the body of the vertebra, the patient is placed in 5 to 10 degrees Trendelenburg position and 20 ml of local anesthetic solution is injected. The drug flows cephalad to encompass the sympathetic chain as high as L-2. The advantages of this procedure over the classic technic are that it is less painful, less apt to produce paresthesias and inadvertent sensory anesthesia, and easier to perform.