What is the function of the hypogastric nerve?

Function of the Hypogastric Nerve

The hypogastric nerve is a critical component of the pelvic autonomic nervous system that provides sympathetic innervation to pelvic organs, controlling urinary, bowel, and sexual function.

Anatomical Structure and Location

The hypogastric nerve is the most superficial and readily identifiable component of the inferior hypogastric plexus 1. It follows a predictable course in the pelvis:

• Originates from the superior hypogastric plexus
• Travels through the retroperitoneum at the level of the pelvic brim
• Extends from the sacrum to the genital organs at the level of the lower sacral vertebrae 2
• Located medial to the internal iliac vessels and deep to the peritoneum

Primary Functions

1. Sympathetic Innervation

• Carries sympathetic signals to the internal urethral and anal sphincters 3
• Provides visceral proprioception to pelvic organs 3
• Controls smooth muscle contraction in pelvic organs

2. Urinary Function

• Maintains tone of the internal urethral sphincter
• Contributes to urinary continence
• Damage can lead to urinary dysfunction in 2.4%-17.5% of patients following pelvic surgery 3

3. Bowel Function

• Innervates the rectum from its anterolateral aspect 2
• Contributes to anal sphincter control
• Helps maintain fecal continence

4. Sexual Function

• Provides innervation to genital organs 4
• In males: contributes to innervation of the prostate, seminal vesicles, and erectile tissue 5
• In females: innervates the uterus and vagina

Clinical Significance

The hypogastric nerve is particularly important in surgical contexts:

1. Surgical Landmark: Serves as an important landmark for preservation of pelvic autonomic innervation during surgery 1

2. Nerve-Sparing Techniques: Can be identified, dissected, and spared during pelvic surgery to prevent autonomic dysfunction 3

3. Pain Management: The superior hypogastric plexus (from which the hypogastric nerve originates) can be targeted for neurolysis to provide relief for uncontrolled abdominal visceral pain, particularly in the lower abdomen or pelvis 6

4. Surgical Risk: Damage during pelvic surgery can result in:

   • Urinary dysfunction
   • Bowel dysfunction
   • Sexual dysfunction

Surgical Preservation Approach

A stepwise approach to identify and preserve the hypogastric nerve during surgery includes 1:

1. Transperitoneal identification with a pulling maneuver for confirmation
2. Opening the retroperitoneum at the pelvic brim and identifying the ureter
3. Medial dissection to identify the hypogastric nerve
4. Lateralization of the nerve to allow safe resection of pathology (such as endometriosis)

Pitfalls and Considerations

• The nerve follows a predictable course but can be difficult to visualize without proper surgical technique
• Knowledge of topographic anatomy and awareness of landmarks are crucial for avoiding intraoperative nerve injuries 3
• Direct visualization techniques similar to those used to preserve ureters can help protect these nerves during radical pelvic surgery 3
• Iatrogenic lesions of the hypogastric nerve and inferior hypogastric plexus are common causes of post-surgical bladder, bowel, and sexual dysfunction 2

Understanding the function and location of the hypogastric nerve is essential for maintaining quality of life in patients undergoing pelvic surgery, as damage to this structure can lead to significant morbidity related to urinary, bowel, and sexual function.