Genitofemoral nerve neuralgia is a common pain syndrome observed in female as well as male patients. Pain is observed over lower abdomen mostly unilateral, very rarely bilateral. Pain may be referred to groin (along genital branch) and inner thigh (along femoral branch). Pain is intense at time with extension of lower back or palpation of groin over inguinal region. Most common cause of pain is pinch nerve in inguinal canal after inguinal hernia repair. Genitofemoral nerve originates at spinal segment of L1 and L2 spinal cord. Nerve divides in to genital and femoral branch at inguinal ligament.
Genitofemoral neuralgia is one of the most common causes of lower abdominal and pelvic pain observed in clinical practice. Genitofemoral neuralgia may be caused by compression of or damage to the genitofemoral nerve anywhere along its path.
Classification of Genitofemoral Neuralgia
- Acute Pain less than 3 months, mostly nociceptive pain
- Chronic Pain more than 3 to 6 months, mostly neuropathic pain
Classification and Types of Acute pain:
Pain is classified into:
- Nociceptive pain.
- Neuropathic Pain.
Common Symptoms of Genitofemoral Neuralgia
- Common Nerve lesion symptoms involves genital and femoral branch.
- Pain from genital branch spread into scrotum in male and labia major in female, pain could.
- Pain from femoral branch inner side of thigh never spreads below knee joint.
Pathophysiology of Genitofemoral Neuralgia
It is a mixed nerve but consist of predominant sensory fibers. It is L1 and L2 segment of spinal cord. It passes through psoas muscle distal to L1 and L2 foramina. It lies within upper 1/3rd of psoas muscle. It pierces through muscles and lies anteriorly over lower 1/3rd of psoas muscles. Distally nerve is placed between ureter and psoas muscle. It divides into genital and femoral branch just above the inguinal ligament. Genital branch passes into inguinal canal in male and round ligament of the uterus in female. Femoral branch accompanies external iliac artery. It lies lateral to femoral artery below the inguinal ligament. Cremaster reflex involves both afferent and efferent nerves of genitofemoral nerve. Genitofemoral nerve pain is referred along the anatomical distribution of genital and femoral branch.
Pain may spread along femoral or genital branch or both depends on anatomical location of lesion. If nerve were pinch proximal to division of nerve, pain would be referred to genital and femoral branch. Genitofemoral nerve lesion after division involves either genital or femoral branch. Symptoms signify the anatomical location of injury.
Causes of Genitofemoral Neuralgia
- Injury :
- Groin injury: cut, laceration, abrasion.
- Inguinal canal: blunt injuries, sprain of inguinal ligament.
- Lower back-auto accident: whiplash injury, work injury lifting object.
- Spinal Canal: Transformational stenosis, paravertebral tumor or metastasis causing foraminal stenosis as L1 and L2.
- Psoas Abscess: causes pressure on genitofemoral nerve.
- Pelvic Tumor or Abscess: causes pressure on nerve.
- Surgery: Pain following inguinal hernia repair, scar tissue pinching nerve.
Symptoms and Signs of Genitofemoral Neuralgia
Chronic Intractable Pain
- Mild (score 1 to 3 of 10)- foraminal stenosis, pinch nerve lesion at inguinal canal
- Moderate (score 4 to 6 of 10)- foraminal stenosis, pinch nerve lesion at inguinal canal, psoas abscess and pelvic mass
- Severe (score 7 to 10 of 10)- foraminal stenosis, inguinal canal scar tissue pinching nerve, psoas abscess, pelvis tumor pressing nerve.
- Lesion before division : pain referred along femoral and genital branch of genitofemoral nerve; Groin, scrotom, inner thigh
- Lesion Genital branch:
- Male : Pain along scroom and groin
- Female : Pain along groin and libia majora
- Lesion Femoral branch : Groin and medial skin of thigh, pain never refers below knee.
- Character : Sharp, burning, stabbing, incisional pain over inguinal canal,
- Paresthesia : Over lower abdomen and inner side of thigh
- Numbness : Lower abdomen, inguinal dermatome, scrotom or inners skin of thigh, labia majora in female
- Extension of spine : Pain is worst, traction on nerve
- Flexion of spine : Pain is less severe, skier's position, patient prefer this position
- Weakness of anterior abdominal wall
Pain Following Inguinal Hernia Surgery:
- Nociceptive pain
- Temporary and last until wound is healed.
- Requirement of pain meds are higher during first few days
- Scar tissue causing pinch of nerve- chronic pain and neuropathic.
- Could be lower or higher. Change of pain behavior
- Decrease pain tolerance- recovery will be slow, pain may become chronic neuropathic.
- Increase pain tolerance- recovery can be faster. Work hardening and occupational therapy- can change pain behaviour. Secondary Gain-patient will maintain continuous severe intensity of pain
- Caused by: Family sympathy and extra attention by close family members; Paid disability for not going to work. External behaviour- promoted by added benefits from employer or families.
- Symptoms substantially exaggerated.
- Acute pain become chronic intense pain in due course of time
- Psychological in origin- patients may not recognize these symptoms, not deliberate act. Unconscious psychological part of the symptoms and not malingering.
- Early recognition and elimination- is better and recovery is faster.
- Motivation: Positive internal motivations.
- Attitude : Feel better soon
- Resume normal activities: feeling of getting better to resume normal activities primary gain.
- Prognos-Recovery: Individual may not recovered 100% in short period of time.
- Occupational therapy and work hardening- should be considered sooner if secondary gain is suspected.
- Approval or denial- by third party payer and insurance co will determine the course of treatment and prognosis.
- Functional impairment- if less than 30 to 40%, patient could be encourage to go back to work with work restrictions. Returning to work and performing restricted work adds to rehab and work hardening.The familiar surrounding of work helps to reduced psychological trauma and builds confidence to enhance performance.
- Acceptance to resume work- Employer may not permit to resume work with restriction.
Goal: Recover as soon as possible and get back to near normal activities. Acute pain After 3 to 4 months- recovery could be slow, further treatment will be necessary. Side effects: to medications and interventional treatment- delays recovery.
Treatment for Genitofemoral Neuralgia
1. Medications for Genitofemoral Neuralgia
Initial Medications for Genitofemoral Neuralgia
- Tylenol – Acetaminophen.
- Non Steroidal anti-inflammatory drugs (NSAIDs) e.g Motrin (Advil) naproxen (Aleve).
- Topical (local anesthetics spray or ointment).
- Corticosteroids in smaller dosage.
Later Medications for Genitofemoral Neuralgia
- Opioids - tramadol, vicodine, oxycodone, morphine.
- Antidepressants - Tricyclic antidepressants, Cymbalta.
- Anticonvulsants - Neurontin, Lyrica.
2. Alternative Treatment for Genitofemoral Neuralgia
- Tactile stimulation - TENS units
- Cold pack
- Physical Therapy
- Interventional Therapy-Genitofemoral Nerve block Trigger point injection Cryo-nerve ablation of G-F nerve
- Psychotherapy- workman comp cases assist to eliminate secondary gain
- Relaxation techniques such as deep breathing
- Low Intensity Laser Therapy (LILT)
Investigations for Genitofemoral Neuralgia
- Blood Examination: rules out infection, abscess.
- X-ray: rules out dislocation of joint, fracture of bones.
- CAT Scan and MRI: Rules out fracture, dislocation, intestinal obstruction.
- Ultrasound: rules out obstruction, stones, intra-abdominal pathology.
- Bone scan: rules out arthritis, CRPS (chronic regional pain syndrome.)