Superior Hypogastric Plexus Block

Published on 06/02/2015 by admin

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Last modified 06/02/2015

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48 Superior Hypogastric Plexus Block

Perspective

The superior hypogastric plexus block is conceptually patterned after the use of neurolysis of paravertebral neural plexuses to provide intra-abdominal or lower extremity pain relief. Gynecologic surgeons have performed presacral neurectomy for many years to treat a variety of pelvic pain syndromes, and this surgical procedure is designed to interrupt the superior hypogastric plexus. The superior hypogastric plexus block is used for both diagnostic and therapeutic purposes in patients with both benign and cancer pain syndromes. Nevertheless, much of the focus remains on neurolysis to provide pain relief for patients with pelvic cancer pain syndromes who are otherwise difficult to treat.

Patient Selection

When superior hypogastric plexus block is used diagnostically in patients with chronic benign pelvic pain syndromes, it is designed to help define the source of the pain. It is used less frequently for this purpose than for neurolysis of the plexus to produce long-lasting pain relief in patients with pelvic cancers. Cancer pain syndromes that may be amenable to relief with a superior hypogastric plexus block include cervical, proximal vaginal, uterine, ovarian, testicular, prostatic, and rectal cancers. The technique has also been used to relieve pain in patients with distal colonic or rectal inflammatory bowel disease.

Pharmacologic Choice

During diagnostic blocks, the choice of local anesthetic should be determined by the desired duration of the block. Often, 0.25% bupivacaine or 0.2% ropivacaine with 1:200,000 epinephrine is used through bilaterally placed needles to a total dose of 20 to 30 mL. Shorter-acting local anesthetics such as 1% lidocaine, again often with 1:200,000 epinephrine, are also used effectively. When neurolysis is the goal, a radiocontrast agent, 2 to 4 mL through each needle, is used to ensure correct needle position; 8 to 10 mL of 10% aqueous phenol or 50% alcohol can be used as the neurolytic agent.

Placement

Anatomy

The superior hypogastric plexus is continuous with the intermesenteric plexus and is located retroperitoneally, caudad to the origin of the inferior mesenteric artery. It lies anterior to the lower part of the abdominal aorta, its bifurcation, and the middle sacral vessels; more specifically, it is anterior to the fourth and fifth lumbar vertebrae and the first sacral vertebra. The plexus is composed of a flattened band of intercommunicating nerve bundles that descend over the aortic bifurcation (Figs. 48-1 and 48-2). Broadening below, it divides into the right and left hypogastric nerves. In addition to its continuity with the intermesenteric plexus, the superior hypogastric plexus receives input from the lower two lumbar splanchnic nerves (Fig. 48-3). Figure 48-3 identifies with a red triangle a key concept in the superior hypogastric plexus nerve block. The red triangle highlights the anatomic window between the iliac crest, the L5 transverse process, and the L5-S1 vertebral bodies, which allows successful needle insertion.

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Figure 48-1.

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