THE CLINICAL SYNDROME
Genitofemoral neuralgia is one of the most common causes of lower abdominal and pelvic pain encountered in clinical practice. Genitofemoral neuralgia may be caused by compression of or damage to the genitofemoral nerve anywhere along its path. The genitofemoral nerve arises from fibers of the L1 and L2 nerve roots. The genitofemoral nerve passes through the substance of the psoas muscle, where it divides into a genital and a femoral branch. The femoral branch passes beneath the inguinal ligament along with the femoral artery and provides sensory innervation to a small area of skin on the inside of the thigh. The genital branch passes through the inguinal canal to provide innervation to the round ligament of the uterus and labia majora in women. In men, the genital branch of the genitofemoral nerve passes with the spermatic cord to innervate the cremasteric muscles and provide sensory innervation to the bottom of the scrotum.
The most common causes of genitofemoral neuralgia involved injury to the nerve induced by trauma, including direct blunt trauma to the nerve, as well as damage during inguinal herniorrhaphy and pelvic surgery. Rarely, genitofemoral neuralgia will occur spontaneously.
SIGNS AND SYMPTOMS
Genitofemoral neuralgia presents as paresthesias, burning pain, and occasionally numbness over the lower abdomen that radiates into inner thigh in both men and women and into the labia majora in women and the bottom of the scrotum and cremasteric muscles in men. The pain does not radiate below the knee. The pain of genitofemoral neuralgia is made worse by extension of the lumbar spine, which puts traction on the nerve. Patients suffering from genitofemoral neuralgia will often assume a bent-forward novice skier’s position.
The pain of genitofemoral neuralgia will radiate into the inner thigh of men and women and into the labia majora in women and inferior scrotum in men.
Physical findings include sensory deficit in the inner thigh, base of the scrotum, or labia majora in the distribution of the genitofemoral nerve. Weakness of the anterior abdominal wall musculature may occasionally be present. Tinel’s sign may be elicited by tapping over the genitofemoral nerve. Weakness of the anterior abdominal wall musculature may occasionally be present. Tinel’s sing may be elicited by tapping over the genitofemoral nerve at the point it passes beneath the inguinal ligament. As mentioned, the patient may assume a bent-forward novice skier’s position.
Pharmacologic management of genitofemoral neuralgia is usually disappointing, and nerve block will often be required to provide pain relief. Initial treatment of genitofemoral neuralgia should consist of simple analgesics, nonsteroidal anti-inflammatory drugs, or cyclooxygenase-2 inhibitors. Avoidance of repetitive activities thought to exacerbate the symptoms of genitofemoral neuralgia (e.g., squatting or sitting for prolonged periods) will also help ameliorate the patient’s symptoms. If the condition fails to respond to these conservative measures, a next reasonable step is genitofemoral nerve block with local anesthetic and steroid.
Genitofemoral nerve block is performed by placing the patient in supine position with a pillow under the knees, if lying with the legs extended increases the patient’s pain due to traction on the nerve. Genitofemoral neuralgia is a common cause of lower abdominal and pelvic pain. Genitofemoral nerve block is a simple technique that can produce dramatic relief for patients suffering from genitofemoral neuralgia. As mentioned, pressure should be maintained on the injection site after the block to avoid ecchymosis and hematoma formation. For patients who do not rapidly respond to genitofemoral nerve block, consideration should be given to epidural steroid injection of the L1-2 segments.
Correct needle placement for genitofemoral nerve block.