What Is A Superior Hypogastric Plexus Block?
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The superior hypogastric plexus is located in the retroperitoneum. This network of nerves extends bilaterally from the lower third of the fifth lumbar vertebrae to the upper third of the first sacral vertebrae. The superior hypogastric plexus is comprised of efferent sympathetic neurons and afferent pain fibers that enervate the bladder, vulva, vagina, uterus, urethra, penis, perineum, prostate, testes, rectum, and colon. Thus, interrupting the function of this neural network can lead to pain-relieving benefits within these structures.
The risks associated with superior hypogastric plexus blocks are very low. In fact, only one published study reported complications with regard to this procedure. More specifically, one patient was reported to have developed somatic nerve damage following a superior hypogastric plexus block with computerized tomography scan-guided imagery. Additional neurological complications were not reported in relation to superior hypogastric plexus blocks.
Nonetheless, many believe that several theoretical risks exist with regard to this procedure. These possible risks include:
- Needle misplacement resulting in bleeding
- Injury to neural tissue
- Accidental puncture of surrounding organs
- Accidental puncture of surrounding vessels
- Distal ischemia
While there are relatively few studies available that have examined the effectiveness of this interventional technique for managing pain, results have suggested that superior hypogastric plexus blocks can decrease Visual Analogue Pain Scores (VAPS) and lead to significant reductions in opioid usage.
How Is A Superior Hypogastric Plexus Block Performed?Ideally, the superior hypogastric plexus block is performed through the posterior approach, which requires that the patient lie in the prone position (i.e., lying face down). This position, however, may cause the patient to experience too much discomfort. As such, the superior hypogastric plexus block can be performed through either the transdiscal or the anterior approach, which do not require the patient to be positioned lying face down. The transdiscal approach can be done with the patient lying on their side and utilizes either fluoroscopic or computed tomography guidance. The anterior approach is performed using either ultrasound, fluoroscopic, or computed tomography guidance. The posterior approach utilizes fluoroscopic guidance, which is generally preferred by most practitioners, as it reduces the patient’s exposure to radiation.
Prior to the injections, the skin around the area of the two injection sites is thoroughly cleansed and sterilized. The physician will then apply a topical local anesthetic to numb the surface of the skin where the needles will be injected. Using an imaging technique as a guide, the injection needle is then guided into the back, through the intervertebral discs, and into the area of the superior hypogastric plexus. Contrast dye is administered first, to confirm the correct location of the needle. Once the proper placement has been assured, the anesthetic solution is injected into the area of the superior hypogastric plexus. A neurolytic agent, such as alcohol or phenol, may be combined with the anesthetic in order to ablate, or destroy, the neural tissue within the area. Further, radioablation may be used to provide more long-term relief from pain. This technique involves the use of very high degrees of heat to ablate neural tissue in the area.
In most cases, the superior hypogastric plexus block procedure takes less than 15 minutes. Once the injection needle has been removed, the patient is retained for a period of time in order to monitor for any adverse reactions from either the procedure or the medication.
It is not uncommon for patients receiving a superior hypogastric plexus block to report pain relief almost immediately following the injection. In fact, a majority of patients undergoing this procedure are expected to experience relief from pain within 24 hours following their discharge. While there is no way to predict how each patient will respond to this procedure, most patients can expect generally long-term benefits from a superior hypogastric plexus block. Nonetheless, there is a portion of patients whose symptoms of pain and discomfort will return following a brief period of being pain-free.
Conditions Related To Superior Hypogastric Plexus BlocksThe superior hypogastric plexus block is an interventional treatment technique that is used to specifically target neuropathic pain occurring in the pelvic region.
Common conditions treated with this procedure include:
- Refractory penile pain
- Conditions affecting the reproductive organs, such as the uterus or testes
- Chronic pelvic pain, particularly related to malignancies
- Intractable anal pain
- Descending colon
- Colorectal cancer
- Genitourinary cancer
- Gynecologic cancer
- Radiation injuries (e.g., to the muscles or nerves)
ConclusionThe superior hypogastric plexus block procedure involves interrupting, or blocking, the transmission of pain signals within the superior hypogastric neural network. This is done through a minimally invasive technique that does not require surgery. The superior hypogastric plexus block is effective in treating neuropathic pelvic pain. There are very few risks associated with this procedure. The entire procedure takes less than 15 minutes to complete and the majority of patients report experiencing a significant reduction in the severity of their pain almost immediately.
Superior hypogastric plexus blocks are not for everyone. Patients are encouraged to speak with their physician about the risks and benefits associated with the procedure, and whether or not a superior hypogastric plexus block is right for them.
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