Ultrasound-guided superior hypogastric plexus block is useful in the diagnosis and treatment of a variety of painful sympathetically mediated painful conditions of the pelvic viscera including pain secondary to malignancy, endometriosis, reflex sympathetic dystrophy, causalgia, proctalgia fugax, and radiation enteritis. Superior hypogastric plexus block is also useful in the palliation of tenesmus secondary to radiation therapy to the rectum. Superior hypogastric plexus block with local anesthetic can be used as a diagnostic tool when performing differential neural blockade on an anatomic basis in the evaluation of pelvic and rectal pain. If destruction of the superior hypogastric plexus is being considered, this technique is useful as a prognostic indicator of the degree of pain relief that the patient may experience. Superior hypogastric plexus block with local anesthetic and/or steroid is also useful in the treatment of acute herpes zoster and postherpetic neuralgia involving the sacral dermatomes (Fig. 129.1). Destruction of the superior hypogastric plexus is a reasonable next step in the palliation of pain syndromes that have responded to superior hypogastric plexus blockade with local anesthetic and have not responded to more conservative measures.

In the context of ultrasound-guided injection techniques, the superior hypogastric plexus can simply be thought of as a continuation of the lumbar sympathetic chain that can be blocked in a manner analogous to lumbar sympathetic nerve block. The preganglionic fibers of the superior hypogastric plexus find their origin primarily in the lower thoracic and upper lumbar region of the spinal cord. These preganglionic fibers interface with the lumbar sympathetic chain via the white communicantes. Postganglionic fibers exit the lumbar sympathetic chain and, together with fibers from the parasympathetic sacral ganglion, make up the superior hypogastric plexus. The superior hypogastric plexus lies in front of L4 as a coalescence of sympathetic nerve fibers. As these fibers descend, at a level of L5, they begin to divide into the hypogastric nerves following in close proximity the iliac vessels (Fig. 129.2). As the hypogastric nerves continue their lateral and inferior course, they are accessible for neural blockade as they pass in front of the L5-S1 interspace, which is the key sonographic landmark when performing ultrasound-guided superior hypogastric plexus block (Fig. 129.3). The hypogastric nerves pass inferiorly from this point, following the concave curve of the sacrum and passing on each side of the rectum to form the inferior hypogastric plexus (Fig. 129.4). These nerves continue their downward course along each side of the bladder to provide innervation to the pelvic viscera and vasculature.

Ultrasound-guided superior hypogastric plexus block can be carried out by placing the patient in the prone position with a thin pillow under the hips (Fig. 129.5). A syringe containing 18 mL of 0.5% preservative-free lidocaine is attached to a 22-gauge, 13-cm needle. The superior extent of median dorsal crest of the sacrum is identified by palpation as is the iliac crest (Fig. 129.6). After preparation of the skin with antiseptic solution, a curvilinear low-frequency ultrasound transducer is placed in the longitudinal plane ˜3 cm laterally from the center of the previously identified median dorsal crest of the sacrum, and an ultrasound survey scan is taken (Fig. 129.7). The dorsal surface of the sacrum will appear as a flat hyperechoic line with an acoustic shadow beneath it (Fig. 129.8). The inflection or gap between the sacrum and the lamina of L5 is the L5-S1 intervertebral space (see Fig. 129.8). After the L5-S1 inflection representing the L5-S1 interspace is identified, the longitudinally placed transducer is slowly moved cephalad until the L4-L5 interspace is visualized (see Fig. 129.8). After satisfactory identification of the L4-L5 interspace, the ultrasound transducer is turned 90 degrees to the transverse plane, and another ultrasound survey scan is taken (Fig. 129.9). Note that the transverse processes block ultrasound visualization of the lateral margin of the vertebral body (Figs. 129.10 and 129.11).
Once the transverse process is identified, the ultrasound transducer is slowly moved in a cephalad direction to identify the acoustic window between two adjacent transverse processes (Fig. 129.12). Once the acoustic window between the adjacent transverse processes is identified, the lateral aspect of the ultrasound transducer is rocked laterally to identify the lateral margin of the vertebral body and the adjacent psoas muscle (Figs. 129.13, 129.14 and 129.15). A color Doppler image is then obtained to identify adjacent vasculature to avoid inadvertent intravascular injection (Fig. 129.16).