Thigh Pain / Meralgia Paresthetica
Do you have chronic pain, burning and/or numbness on the front/side of your thigh? It is probably due to an injury or compression of a nerve called the Lateral Femoral Nerve (LFN).
“Meralgia Paresthetica” is the name for compression of this nerve as it crosses around the front of the hip (like Carpal Tunnel Syndrome at the wrist). The result of this “pinched nerve” is pain or numbness on the side of the thigh. It is often worsened with walking and other exercise because the nerve is further irritated by these movements.
Nerves do not like to be “squeezed’. There are narrow spaces (like tunnels) that nerves pass through in particular areas of the body. Some people develop abnormally tight tunnels, which pinch the nerves running through them.
This results in pain or numbness in the area of skin that the nerve carries sensation from. The nerve compression and resulting pain can happen to anyone, but some jobs have more risk of it – like police officers, firefighters and construction workers – due to wearing heavy, loaded belts around the waist. The excess repetitive pressure can lead to the LFN nerve being pinched. Sports like karate, kickboxing, football, soccer, rugby and others can all cause injuries that result in this problem. Weight changes such as obesity or pregnancy can also contribute to repetitive stress and stretching of the nerve.
Diabetic patients have a higher chance of developing a pinched LFN nerve due thigh sugar levels which cause swelling of their nerves. The result is compression of the LFCN nerve where it runs through tight spaces at the front of the hip. Like a napkin ring around an animal balloon, as the balloon swells, the napkin ring gets tighter and tighter. Pain and numbness in the side of the thigh are the result. Therefore, diabetic patients are at a higher risk for experiencing symptoms of Meralgia Paresthetica than other people.
Operations, injuries and falls can cause cuts, scarring or stretching to the LFN nerve at the hip, resulting in pain on the front/side of the thigh.
Car accidents and falls that cause bruising and swelling of the skin can also lead to damage to the LFN nerve.
Operations on the thigh or groin that are near the LFN nerve (for example, hip surgery, hernia surgery, bone graft harvest and cesarean section are some of the most common. The operation can leave behind internal scar tissue that attaches to the nerve and causes pain.
The pain may develop weeks or years after the operation or the trauma, due to the effect of the bruise or scar on the nerve, and therefore some patients may not realize what caused the pain.
With a simple physical exam and possibly a local anesthetic injection, Dr. Brown and Dr. Hagan can easily determine if your LFN nerve is injured and if it is responsible for causing your pain. An injection, also known as “a nerve block”, is a simple test that is quick, nearly painless to go through and can be done during an office visit. Doctors Brown and Hagan are experts at knowing the location of this nerve, and use ultrasound to see the nerve through the skin, and direct the local anesthetic directly to it. If the injection is successful in relieving the pain for a few hours (the duration of the anesthetic), then the surgeons may recommend a straightforward outpatient operation that can make the pain relief permanent.
Once you have been identified to have symptoms of Meralgia Paresthetica (compression of the Lateral Femoral Nerve / LFN) several other potential issues should be addressed. In some cases, lower (lumbar) spine problems should be ruled out with an MRI. An MRI can also rule out any mass or tumor as the cause for compression of the nerve . Ultrasound-guided diagnostic injections are routinely used to confirm the diagnosis. In some cases, steroid injections can be used to decrease swelling around the nerve, and provide pain relief.
If the severity of the pain is not too bad, non-surgical remedies may be tried. These may include medications such as gabapentin, amitriptyline, etc., topical compound creams, lifestyle changes (avoidance of painful activities to let swelling around the nerve go down), weight loss and physical therapy. If the pain is more severe or long-standing, or non-surgical therapies fail after 3 months, surgery may be a good option.
Surgical decompression of the nerve (just like carpal tunnel surgery) is successful in most people(80-85%). This operation is straightforward and is performed as an outpatient. If decompression does not solve the pain, there is still hope. A second operation to go back and cut out the nerve is the back-plan. This will cause a numb spot on the thigh in place of the pain – a welcome trade-off!
Nerve Surgery Helps Relieve Chronic Pain
The majority of patients with chronic pain report significant decreases or complete resolution of their pain following nerve surgery. Most patients describe the ‘nerve pain feelings’ are improved as soon as the following day. Discomfort from the operation is frequently described as a completely different sensation, which subsides in the next few weeks.