Case Study-Meralgia Paresthetica

35 years old female was referred to me due to the right sided lower back pain, lateral thigh pain and lateral knee pain for 3 year duration. The patient was diagnosed as disc herniation with radiculopathy, hip osteoarthritis, knee osteoarthritis and myalgia. She was treated with interventional pain management procedures, including lumbar epidural steroid injection, transforeminal epidural steroid injection, hip injection, Knee injection, trigger point injection, and greater trochanteric steroid injection without any relief of her pain. The patient had to take Oxycontin 80mg three times a day and Percocet 6 tablets a day. However, the pain was still severe and unbearable.

Examination in my office revealed severe pain on the right buttock, lateral thigh and knee. There is evere pain with any movement of hip and back tests and decreased pin prick sensation in oval shape on the lateral thigh.

There is L4/L5 disc herniation in her MRI of lumbar spine. The EMG test was within normal limits.

Fig 1. L4/L5 disc herniation compresses L5 nerve root.

Fig 2. Lateral femoral cutaneous nerve, formed from L2 and L3

Analysis of the Case:

This is a typical case of entrapment of lateral femoral cutaneous nerve. It is a rare condition and often mistakenly diagnosed as disc herniation, sciatica, radiculopathy, hip arthritis, knee arthritis, greater trochanteric bursitis, or other conditions. It is commonly treated with epidural steroid injection, hip injection, knee injection, bursa injection, and other injections.

Disc hernia may not be the source of the pain. Many people do have disc herniation, but they may not have pain. This is typical case.

When a patient has L4 disc herniation, the nerve which is impinged is L5 nerve root. And the pain of L5 sciatica or L5 radiculopathy is in the leg from low back down to foot. Therefore, This patient did not have sciatica or radiculopathy. The lumbar epidural steroid injection to treat sciatica is not going to help. It is because the pain does not come from disc herniation or sciatica.

The patient with this condition can be treated with variety of injections, such as hip injection, bursa injection, knee injection or other injections because the pain can be confused with knee arthritis, hip arthritis, bursitis and other inflammation conditions.

Diagnosis:

Meralgia Paresthetica

Treatment:

Lateral Femoral Cutaneous Nerve Block

Result:

The pain was resolved after lateral femoral cutaneous nerve block for about a year. The patient took off pain medications completely.

The pain came back in about a year. The pain was resolved for about half year after the second nerve block. The pain was controlled only 3 months after the third nerve block.

The patient was then referred to neurosurgeon. The pain was resolved after the surgery.