Anterior Cutaneous Nerve Entrapment Syndrome

Anterior Cutaneous Nerve Entrapment Syndrome (ACNES) is a condition characterized by chronic pain in the abdominal wall. It occurs when the anterior cutaneous branches of the thoracoabdominal nerves become entrapped as they pass through the abdominal muscles into the subcutaneous tissue. This entrapment can lead to sharp, localized pain that is often mistaken for other conditions such as appendicitis, gallbladder disease, or gastrointestinal disorders.

Etiology

The exact cause of ACNES is not fully understood, but it is believed to be related to mechanical factors such as tight abdominal muscles, previous abdominal surgery, or trauma that leads to nerve compression. Obesity and pregnancy may also increase the risk of developing ACNES due to added pressure on the abdominal wall.

Symptoms

Patients with ACNES typically report localized pain in the abdominal wall that can be sharp, stabbing, or burning in nature. The pain is often exacerbated by certain movements or pressure on the affected area. Unlike visceral pain, the discomfort associated with ACNES is usually confined to a small area that can be pinpointed by the patient.

Diagnosis

Diagnosis of ACNES is primarily clinical, based on the patient's history and physical examination. A positive Carnett's test, where the pain increases or remains unchanged when the patient tenses the abdominal muscles, is indicative of ACNES. Imaging studies such as ultrasound or MRI may be used to rule out other conditions but are not diagnostic for ACNES. Nerve block injections with local anesthetics can also be diagnostic and therapeutic.

Treatment

Treatment options for ACNES include conservative measures such as physical therapy, pain management with non-steroidal anti-inflammatory drugs (NSAIDs), and local anesthetic injections. In cases where conservative treatment fails, surgical intervention to release the entrapped nerve may be considered. Nerve ablation techniques have also been used with varying degrees of success.

Prognosis

The prognosis for patients with ACNES is generally good, especially when the condition is diagnosed early and treated appropriately. Most patients experience significant pain relief with conservative treatment or surgery. However, some patients may have persistent symptoms and require ongoing management.

Epidemiology

ACNES is a relatively common cause of chronic abdominal pain, but it is often underdiagnosed. It can occur in individuals of any age but is more prevalent in young adults and middle-aged individuals. There is no clear gender predilection.

See Also

• Chronic pain
• Abdominal surgery
• Nerve block