Entrapment neuropathies are common disorders which lead to significant disability. Correct diagnosis is essential for proper management. History taking and physical examination are a cornerstone in the diagnosis of the ilioinguinal neuralgia. Patients of ilioinguinal neuralgia complain of pain (mostly postsurgical) in the lateral aspect of the iliac fossa, lower abdomen, and upper thigh, as well as abnormal sensation in the cutaneous distribution of the nerve (hyperesthesia or hypoesthesia). The pain is often burning in nature, continuous, and may radiate to the scrotal or inguinal region.

On examination, there is tenderness on palpation 1 inch medial and inferior to the anterior superior iliac spine and impaired sensation along the sensory distribution of the nerve. Complete neurologic examination is mandatory to exclude genitofemoral neuralgia, lumbosacral radiculopathy, and plexopathy.[10]

1. Ultrasound examination: Tracing the nerve starting from the psoas major border is difficult because of the small size of the nerve and the depth of the nerve, especially in obese patients. It is easy to trace the nerve at the iliac crest down to the superficial inguinal ring and see the cause of the entrapment (for example, the scar of surgery). An ultrasound-guided block can confirm a diagnosis of the ilioinguinal neuralgia.[11]

2. Electrophysiologic studies: The benefit of the electrophysiologic examination for the diagnosis of the ilioinguinal nerve injury is questionable. Electrophysiologic studies are more directed to exclude lumbar radiculopathy and plexopathy.[3]

3. Magnetic resonance imaging: performed on the lumbosacral spine to exclude lumbar radiculopathies.

4. A common method of confirming the diagnosis is by infiltrating the area with a local anesthetic and determining if the patient has relief from pain.

There are multiple strategies to treat chronic groin pain.[12][13] The pain of neuropraxia is typically temporary and disappears with time. Sometimes, the chronic groin pain persists and interferes with the activities of daily living.[5]

A) Conservative treatment[14][15]:

Lifestyle modification:

• Walking, stooping, or hyperextension of the hip joint exacerbates chronic groin pain - the recumbent position and flexion of the hip joint and thigh relieves pain.

Painkillers:

• Includes non-steroidal anti-inflammatory drugs (NSAIDs), opioids, antiepileptics, and antidepressants

Rehabilitation:

• Transcutaneous electric nerve stimulation, myofascial release, and acupuncture can control symptoms of the ilioinguinal neuralgia.

B) Ultrasound-guided nerve block[14]:

Aim:  interruption of the neuronal transmission leading to temporary pain relief.

Substances injected:  local anesthetics (with or without steroids) or neurolytic agents.

Principal: injection of these chemicals prevent neuronal transmission through ilioinguinal nerve fibers either by blocking membrane ion channels or by denaturation of axon proteins.

Technique: 

1. Patient position: supine
2. Use a linear probe with a frequency ranging from 5 to 10 MHz
3. Place the probe transversely and start scanning from the anterior superior iliac spine.

The nerve lies between transversus abdominis and internal oblique muscles lateral to the inferior epigastric artery and the iliohypogastric nerve. Operators introduce a needle from lateral to medial using an in-plane approach to place the injectate accurately around the nerve.

C) Surgical treatment[15][5]:

Indications: Persistent, intractable pain after the failure of conservative measures.

Principal: Neurectomy involves identifying and dissecting the nerve proximal to the area of trauma, or if possible, the entire length of the nerve.

The approach can be open or laparoscopic.

Differential diagnosis includes:

• Lumbar radiculopathy
• Lumbar plexopathy
• Genitofemoral  neuralgia
• Ilio-hypogastric neuralgia
• Inguinal hernia
• Hydrocele
• Varicocele.

A thorough history, physical examination, electrophysiologic studies, ultrasound examination, magnetic resonance imaging, and individual nerve block can help differentiate the exact cause of the lower abdomen and groin pain.[16]

Chronicity of the pain after injury or entrapment of the ilioinguinal nerve is not uncommon. But, the majority of patients respond well to nerve block or surgical neurectomy. However, some patients may continue to have burning pain for months or years. This pain is often unaffected by the usual analgesics; patients may require management by a pain specialist in such cases.

1. Complications of the non-steroidal anti-inflammatory drugs[17][18][19]:

• Gastritis
• Peptic ulcer
• Nephropathy
• Hepatotoxicity
• Hypertension
• Bleeding/thrombosis

2. Complications of the central painkillers as gabapentin[20]:

• Ataxia
• Dizziness
• Fatigue
• Somnolence
• Fever
• Nystagmus
• Peripheral edema

 3. Complications of the nerve block[21][22][23][24]:

• Peripheral nerve injury or vascular injury.
• Transient femoral anesthesia 
• Bowel perforations
• Pelvic hematomas

Ultrasound guidance lowers the incidence of the above-mentioned complications.

• Ilioinguinal blocks require a small volume of injection; the possibility of local anesthetic toxicity is less frequent.

 4. Complications of the neurectomy[5]:

• Infection
• Hematoma
• Seroma
• Testicular edema
• Tingling

• Reduction of body weight
• Avoid positions and activities that precipitate pain

Prevention of the ilioinguinal neuralgia is possible; surgeons should work to avoid injury of the nerves near the field of the surgery and use meshes that don't induce fibrotic reactions. The diagnosis and treatment of ilioinguinal neuralgia need an interprofessional approach. Collaboration between physiatrists, neurologists, pain physicians, and surgeons should direct a proper approach to therapy to improve prognosis. Nurses and therapists should teach patients a healthy lifestyle to minimize pain and improve the activities of daily living. The pain can be severe, and it is best to involve the pain specialist and the pharmacist early. The pharmacist should educate the patient on pain medications and their adverse effects. The pain specialist may have to try a variety of medical and non-medical measures to obtain pain relief. While some patients do obtain pain relief, a significant number of patients will have chronic pain that can affect the quality of life. Because the pain may lead to depression and anxiety, a mental health nurse should counsel the patient.