Video Description
The Genitofemoral nerve originates from the ventral rami of L1-L2. Its injury is uncommon in benign minimally invasive gynecologic surgery.
However, when there is distorted anatomy due to adhesions or severe endometriosis, the risk of injury is higher. Therefore, it is important to recognize the anatomical landmarks early in the surgery to prevent injury.
In this video, the genitofemoral nerve location, innervation, and mechanisms of injury will be reviewed. The points will be illustrated by demonstrating dissection of this nerve in a case with significant adhesions.
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University of Saskatchewan
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Video Transcript: Genitofemoral Nerve Sparing Adhesiolysis
Genitofemoral nerve injury is uncommon in typical benign gynecologic surgery. However, when severe adhesions are present, the risk of injury is higher. Here, we present a video on genitofemoral nerve sparing adhesiolysis.
In this video, we will review the anatomy, innervations and mechanisms of injury of the genitofemoral nerve. We will present a case demonstrating significant adhesions to the pelvic sidewall and how the genitofemoral nerve may be avoided. Pelvic landmarks and dissection techniques will be shown.
The genitofemoral nerve arises from the lumbar plexus. It is formed by anterior rami of L1 to L3, most of L4 and part of the subcostal nerve. The lumbar plexus forms in the substance of the psoas major, anterior to its attachment to the lumbar vertebrae. Branches include the iliohypogastric nerve, the ilioinguinal nerve, the genitofemoral nerve, the lateral femoral cutaneous nerve, the femoral nerve and the obturator nerve.
The genitofemoral nerve originates from the L1 and L2 ventral rami. It descends in the substance of the psoas major and emerges at its anterior surface at L3 and L4. Then it courses downwards on the surface of the muscle in retroperitoneal position and crosses laterally, posterior to the ureter. It descends into the pelvis lateral to the external iliac artery.
The genitofemoral nerve divides into two branches, the genital branch and the femoral branch. The genital branch crosses the lower part of the external iliac artery and enters the inguinal canal through the deep inguinal ring, along with the round ligament. It innervates the skin of pubic mons and labia majora.
The femoral branch descends lateral to the external iliac artery and passes behind the inguinal ligament. It pierces the anterior layer of the femoral sheath and fascia lata to supply the skin of the upper anterior thigh.
The genitofemoral nerve has no motor function. The genital branch is responsible for the sensory function of the mons pubis and labia majora, and the femoral branch provides sensory distribution to the skin of the upper anterior thigh. Injury to these nerves can result in impaired sensation to these areas or, in the worst-case scenario, neuropathic pain.
Mechanisms of injury include psoas muscle compression with retractors or large mass adherent to the pelvic sidewall, pelvic sidewall surgery with external iliac lymph node dissection and complex endometriosis surgery with extensive adhesions.
Here, we present the case of a 32-year-old para three with known endometriosis. She previously underwent a caesarean hysterectomy for invasive placentation. She presented with severe chronic pelvic pain following the surgery. She failed numerous medical treatments.
Her symptoms were alleviated with a trial of GnRH agonist. After extensive counselling, she has consented for laparoscopic bilateral salpingo-oophorectomy and adhesiolysis.
Evaluation of the abdomen revealed significant omental adhesions to the anterior abdominal wall. Following midline adhesiolysis, we identified dense adhesions between the left pelvic sidewall, ovary and bowel.
Using a combination of superficial incisions, traction-countertraction, as well as bipolar and ultrasonic energy, the bowel was carefully dissected off the sidewall. The left medial umbilical ligament was used as a landmark. Gentle traction onto this structure was attempted to help in bowel dissection.
The fimbria was first exposed. With the techniques of superficial incisions and gentle blunt dissection, the ovary and the external iliac artery were then revealed. The ureter was located at the junction of the external iliac artery and infundibulopelvic ligament as it crossed into the pelvis.
Lateral to the external iliac artery was the genitofemoral nerve. The infundibulopelvic ligament was lateral to these structures. The gentle blunt dissection technique helped to thin tissue out, allowing a better exposure of the genitofemoral nerve. The infundibulopelvic ligament was then isolated and coagulated using bipolar and ultrasonic energy.
Dissection of the ovary from the pelvic sidewall was then performed. Notice the dense adhesion of the ovary onto the genitofemoral nerve and external iliac artery. A combination of superficial incision, millimetre by millimetre, with scissors, and gentle pushing by blunt dissection with a suction irrigator was utilized to safely separate the ovary from the genitofemoral nerve and external iliac artery.
The push and spread technique was also applied to thin the fibrotic tissue connecting the ovary to the side wall. Once the left ovary was detached, a right oophorectomy was performed, followed by the removal of the specimen. The patient was given oestrogen postoperatively. Her pain significantly improved at her postop visit.
In conclusion, in the case of severe pelvic sidewall adhesions and the absence of a uterus, it is important to recognize pelvic landmarks such as the medial umbilical ligament, the external iliac artery, the genitofemoral nerve, the ureter and the infundibulopelvic ligament. This facilitates the identification of other pelvic structures and in this case, prevents injury to the external iliac artery and the genitofemoral nerve.
Furthermore, careful tissue handling and dissection techniques are crucial. These help to maintain minimal blood loss, develop surgical planes and avoid injuries to pelvic structures.