Lateral Femoral Cutaneous Nerve Block

The lateral femoral cutaneous nerve (LFCN) block is a commonly performed procedure to provide cutaneous anesthesia or analgesia to the front and outside area of the thigh. The block also can help diagnose and treat a disease called meralgia paresthetica. Nerve-related disease of the LFCN is manifested by pain, dysesthesia, or numbness in the area supplied by the LFCN. This information sheet will explain what it is, Dr. Singer can determine if it is for you.

Why is a lateral femoral cutaneous nerve block performed?
The lateral femoral cutaneous nerve is a branch of the lumbar plexus (a nerve bundle of the lower spine). The lateral femoral cutaneous nerve divides into two branches, anterior (towards the front) and posterior (towards the back). The anterior branch supplies the skin of the anterior and lateral regions of the thigh to the knee, while the posterior branch supplies the lateral portion of the thigh, from around the hip to just above the knee. The lateral femoral cutaneous nerve is a sensory nerve, meaning it is not involved in muscle movement. Meralgia Paresthetica is a common condition associated with the lateral femoral cutaneous nerve and can be caused by avoidable actions such as wearing tight clothing or walking or cycling for extended periods of time. This condition is typically associated with entrapment of the lateral femoral cutaneous nerve under the inguinal ligament leading to a feeling of tingling, aching, or burning.

What is a Lateral Femoral Cutaneous Nerve (LFCN) block?
A lateral femoral cutaneous nerve block is a medical procedure used to anesthetize the lateral femoral cutaneous nerve, which supplies sensation to the skin over the outer thigh. This block is often performed to manage pain, particularly in surgical procedures involving the hip or thigh, or for conditions like meralgia paresthetica, where there is nerve compression leading to pain or numbness.

What are the benefits of LCFN block?
The benefits of a lateral femoral cutaneous nerve (LFCN) block include:

1. Pain Relief: Provides effective local anesthesia for surgeries involving the hip, thigh, or pelvis, reducing pain during and after procedures.
2. Reduced Opioid Use: Helps minimize the need for systemic opioids, which can have side effects and pose risks of dependency.
3. Enhanced Recovery: Facilitates earlier mobilization and rehabilitation by managing pain effectively, potentially leading to quicker recovery times.
4. Improved Patient Comfort: Reduces discomfort associated with conditions like meralgia paresthetica, improving quality of life for patients experiencing nerve-related pain.
5. Minimal Invasiveness: The procedure is relatively simple and can be performed with ultrasound guidance, enhancing accuracy and safety.
6. Local Effect: Limits the area of anesthesia, allowing for more targeted pain management compared to more extensive regional blocks.
7. Lower Risk of Complications: Generally considered safe with a low incidence of serious complications when performed correctly.

What happens during the injection?
During the procedure, Dr. Singer injects a local anesthetic near the nerve, typically at the level of the anterior superior iliac spine (ASIS). This can provide effective pain relief and improve patient comfort during and after surgery or for chronic pain management. It's generally regarded as a safe procedure with minimal risks, though potential complications can include infection, hematoma, or transient numbness in the area.

What happens after an injection?
You will be free to get re-dressed and check out at the front desk. It may help to move in ways that hurt before the injection, to see if the pain is still there, but do not overdo it. Take it easy for the rest of the day.

How long will the relief last?
The duration of relief from a lateral femoral cutaneous nerve (LFCN) block can vary based on several factors, including the type of anesthetic used and individual patient characteristics. Generally, relief can last anywhere from several hours to a few days.

• Short-acting local anesthetics (e.g., lidocaine) may provide relief for about 6 to 12 hours.
• Long-acting local anesthetics (e.g., bupivacaine) can extend relief to 24 hours or more.

In some cases, the effects may last longer, especially if there is a residual effect from the nerve block. However, individual experiences may vary, and some patients may require additional interventions for prolonged pain management.

What are other treatment options? Lateral femoral cutaneous nerve radiofrequency ablation (LFCN RFA) is a less commonly performed procedure compared to other nerve ablation techniques, but its use is increasing, particularly for managing chronic pain conditions such as meralgia paresthetica or postoperative pain in the hip and thigh regions.

While exact prevalence rates can vary, LFCN RFA is typically considered when conservative treatments have failed, and the patient has persistent pain that significantly affects their quality of life. Dr. Singer is an expert in this technique and can discuss the procedure in more detail at your appointment.