Published on 07/02/2015 by admin
Filed under Anesthesiology
Last modified 07/02/2015
This article have been viewed 1190 times
David M. Rosenfeld, MD
Lumbar sympathetic blockade was first fully described by Mandl in 1926. Currently, the modality is widely used as a diagnostic and therapeutic procedure in the treatment of a wide variety of medical conditions.
The lumbar sympathetic ganglia are known to control the sympathetic impulses to the lower extremities. These structures may represent either a single fused elongated mass or up to six separate ganglia spanning the L1 to L5 vertebra. As the sympathetic trunk passes into the abdomen, it begins a migration from a position that is more anterior to the vertebral bodies to a true anterolateral position by the midlumbar levels. On the right side, the sympathetic trunk is positioned posterior to the inferior vena cava, and, on the left, it is lateral and slightly posterior to the aorta. Injection techniques that position needles from L2 through L4 have been described. When approaching the ganglia, the best starting point is the area just cephalad to the middle of the body of the L3 vertebral body. This level has the highest probability of encountering the ganglia, variation is less, as compared with at L2 or L4, and the psoas muscle may terminate at the lower part of the L3 vertebra. The psoas muscle is well positioned posterior to the sympathetic chain, thus separating it from the somatic lumbar plexus and leading to fewer complications after injection, compared with other levels of the sympathetic chain.
The indications for lumbar sympathetic blockade fall into three main categories and serve both diagnostic and therapeutic purposes. First are conditions that result in circulatory insufficiency of the lower extremity, including atherosclerotic disease, arterial embolism, thromboangiitis, Raynaud phenomenon, frostbite, and following reconstructive vascular operations. Many of these conditions, such as claudication, rest pain, ischemic ulcers, and gangrene, are painful. The institution of continuous sympathetic blockade can transiently improve regional blood flow and predict the success of surgical sympathectomy or neurolytic therapy.
The second category involves pain from nonvascular causes and includes phantom or stump pain after amputation, varicella zoster or postherpetic neuralgia, renal colic, interstitial cystitis, complex regional pain syndrome, and labor analgesia. For complex regional pain syndrome, blocks are often performed in succession or continuously via a catheter and can improve analgesia and function in conjunction with pharmacologic and physical therapy. Lumbar sympathetic blockade is known to provide relief from the pain associated with the first stage of labor. Lack of effectiveness of lumbar sympathetic blockade for pain relief during the second stage of labor, concerns over potential intrathecal injection, technical difficulty, and the relative efficiency and ease of epidural analgesia have rendered lumbar sympathetic blockade rare in labor and delivery.
A third miscellaneous category includes nonpainful conditions such as lower extremity hyperhidrosis. The block is primarily used for diagnostic and predictive purposes prior to neurolysis or surgical sympathectomy. It has also been attempted on a limited basis to transiently improve renal function in patients with hepatorenal syndrome.
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