Superior Hypogastric Plexus Block
This procedure is indicated for pain that
originates from the pelvis and is unresponsive to lumbar or caudal epidural
blocks. The hypogastric plexus con-tains visceral sensory fibers that bypass
the lower spinal cord. This block is usually appropriate for patients with
cancer of the cervix, uterus, bladder, prostate, or rectum. It may also be
effective in some women with chronic noncancer pelvic pain.
The hypogastric plexus contains not only
postgan-glionic fibers derived from the lumbar sympathetic chain, but also
visceral sensory fibers from the cer-vix, uterus, bladder, prostate, and
rectum. The supe-rior hypogastric plexus usually lies just to the left of the
midline at the L5 vertebral body and beneath the bifurcation of the aorta. The
fibers of this plexus divide into left and right branches and descend to the
pelvic organs via the left and right inferior hypo-gastric and pelvic plexuses.
The inferior hypogastric plexus additionally receives preganglionic
parasym-pathetic fibers from the S2–S4 spinal nerve roots.
The patient is positioned prone, and a 15-cm
needle is inserted approximately 7 cm lateral to the L4–L5 spinal interspace.
The needle is directed medially and caudally under fluoroscopic guidance so
that it passes by the transverse process of L5. In its final position, the
needle should lie anterior to the inter-vertebral disc between L5 and S1 and
within 1 cm of the vertebral bodies in the anteroposterior view. Injection of
radiopaque contrast confirms correct position of the needle in the retroperitoneal
space; 8–10 mL of local anesthetic is then injected. The superior hypogastric
plexus block may also be per-formed using a transdiscal approach, though there
is a risk of discitis associated with this procedure.
Complications include intravascular injection and transient bowel and