Overview of Lateral Femoral Cutaneous Nerve Compression
Lateral femoral cutaneous nerve compression causes abnormal skin sensation and pain in the anterolateral thigh. The main symptoms are tingling, numbness and burning sensation in the lateral thigh, etc. The lateral femoral cutaneous nerve is under excessive pressure or compression, and medication is the mainstay of treatment, together with rehabilitation therapy, and if necessary, nerve block and surgical treatment.
Definition
Lateral femoral cutaneous neuritis is the most common clinical cutaneous neuritis, which is caused by injury to the lateral femoral cutaneous nerve.
The main manifestations are sensory abnormalities in the lower 2/3 of the anterolateral thigh area, such as numbness, pain, and ankylosing sensation.
The lateral femoral cutaneous nerve is a simple sensory nerve that emanates from the lumbar paraspinal plexus, travels through the abdominal cavity, under the inguinal ligament, and enters the subcutaneous tissues of the thigh, where it is easily compressed.
Morbidity
The global prevalence of lateral femoral cutaneous neuritis is approximately 3 to 6 per 100,000 people.
It accounts for 7% to 35% of people who feel discomfort in their legs.
It is most common in people in their 30s and 40s, and has been on the rise in recent years.
The majority of cases are unilateral, and 8% to 12% of patients are bilateral.
Causes
Causes
Localized pressure, trauma, infection, poisoning and systemic diseases can cause lateral femoral cutaneous nerve injury, and the common causes are as follows:
Localized compression
Spinal deformity, hypertrophic spondylitis, spina bifida.
Lumbar transverse process hypertrophy, high lumbar disc herniation.
Inguinal hernia, ureteral stones.
Retroperitoneal tumors and abdominal tumors.
Thigh trauma, pelvic or abdominal infection.
Poisoning: e.g. alcohol, drug poisoning.
Systemic diseases: e.g. diabetes mellitus, arteriosclerosis, thyroid dysfunction, tumors.
High risk factors
The following are high-risk factors for lateral femoral cutaneous neuritis.
Prolonged weight-bearing, use of excessively tight waistbands or belts, wearing tight jeans, etc.
Prolonged exposure to cold and damp environments.
Pregnancy.
Overweight or obesity.
Pathogenesis
The cause of the disease is still unclear, and may be related to the formation of a significant angle when the lateral femoral cutaneous nerve passes through the broad fascia at the thigh.
When the thigh area is active or in a different position, the lateral femoral cutaneous nerve is pulled and rubbed, resulting in edema of the local tissues and thickening of the myofascial sheath capsule that surrounds the nerve, causing compression of the nerve.
Symptoms
Main symptoms
The main manifestation is abnormal sensation and pain in the lower 2/3 of the anterolateral thigh, mostly one-sided involvement, with a few bilateral onset.
Nature of pain: such as tingling, numbness, burning sensation, ankylosis, heaviness and coldness, etc., with numbness and burning sensation predominantly, without muscle strength loss, dyskinesia and other manifestations.
Aggravating or relieving factors: Symptoms may be aggravated by heavy physical labor, prolonged standing and sitting, and relieved after rest.
Complications
Sleep quality is often affected when symptoms are severe.
Sensory hypersensitivity of the affected skin, i.e., the skin on the outer thighs is overly sensitive to touch, hot and cold stimuli, etc., can occur.
There may also be a loss of skin sensation in the area where the nerve is located.
Consultation
Department of Medicine
Neurology
Neurology is recommended when there is numbness, ankylosis, or other sensory abnormalities in the anterior and lateral thighs.
Pain Medicine
Consult the Pain Medicine Department if you are ready to have a nerve block or surgery if medication is not effective or if you have recurring attacks.
Preparation
Consultation: Registration, Preparation of documents, Frequently Asked Questions
Tips for medical treatment
Fasting is required on the morning of the visit. Blood tests may be required.
Preparation Checklist
Symptom list
Pay special attention to the time of onset of symptoms, special manifestations, etc.
Where is the discomfort?
What is the nature of the discomfort?
How long has the discomfort lasted?
Is it related to cold, dampness, weight bearing, prolonged standing?
Medical History Checklist
Any previous lumbar disc herniation, history of pelvic tumors, pelvic inflammatory disease, etc.?
Is there any history of trauma to the thighs, iliolumbar region, infection, etc.?
Is there any history of systemic disease such as diabetes, thyroid dysfunction, tumor, etc.?
Checklist
Test results of the last six months, which can be brought to the doctor’s office
Laboratory tests: blood routine, blood glucose, glycosylated hemoglobin, thyroid function, etc.
Electrophysiologic examination: nerve conduction velocity examination, somatosensory evoked potential examination.
Imaging tests: pelvic CT or magnetic resonance, ultrasound of the thigh area.
List of medications used
Medications used in the last 3 months, if available in boxes or packages, bring them to the doctor’s office
Vitamins: vitamin B1, methylcobalamin.
Glucocorticoids: methylprednisolone, prednisone.
Anti-inflammatory analgesics: ibuprofen, diclofenac sodium.
Diagnosis
Diagnosis is based on
Medical history
History of lumbar disc herniation, tumor, diabetes mellitus, pelvic infection, trauma to the thighs and lumbosacral region.
Clinical manifestations
Symptoms
Abnormal sensation such as numbness, pain, ants sensation in the lower 2/3 of the anterolateral thigh.
Physical signs
The doctor will find out whether there are any abnormalities in motor, sensory, and sensory nerve functions as well as tendon reflexes through physical examination, paying attention to bilateral comparisons during the examination.
Motor function examination: Observe whether assistance is needed to complete movements such as lifting the thighs, sitting up, standing and walking.
Skin sensory examination: Slide a cotton swab over the skin of the thigh or gently prick the skin with a blunt needle to assess the degree of sensory impairment according to the sensitivity to sensation.
Sensory nerve function examination: gently tap the anterolateral thigh from the lower thigh to see if it causes or aggravates discharge-like pain, numbness, or ankylosis in the anterolateral thigh.
Tendon reflex examination: observe the contraction of thigh muscles when tapping the patellar ligament at the knee joint.
Laboratory tests
Routine blood test
Purpose of the test: To determine whether there is any infection or inflammation in the body.
Significance of the test: If the result indicates high white blood cells, it suggests that there may be an infection.
Blood biochemistry test
Blood Glucose, Glycated Hemoglobin and Glucose Tolerance
Purpose: To determine the presence of diabetes/abnormal glucose tolerance and the level of recent blood glucose control.
Significance: If blood glucose is higher than normal several times or glycated hemoglobin is too high, it suggests that diabetes mellitus may be present or that diabetic patients have had poor control of their blood glucose level in the past 3 months.
Note: Fasting is required before the test.
Thyroid Hormone Test
Purpose of the test: to determine whether there is an abnormality in the function of the thyroid gland.
Significance: Increased or decreased levels of thyroid stimulating hormone and thyroid hormone may indicate the presence of hyperthyroidism or hypothyroidism.
Precautions: Avoid drinking strong tea and coffee before the test, fasting is required, and avoid stress before the test.
Electrophysiologic examination
Including somatosensory evoked potentials, nerve conduction velocity and electromyography.
Purpose of the examination: to determine whether there is damage to the lateral femoral cutaneous nerve.
Significance: If the nerve conduction velocity and latency of the affected side are significantly abnormal compared with the opposite side, it suggests that there may be damage to the lateral femoral cutaneous nerve. Electromyography generally shows no abnormality.
Precautions: The day before the examination, take a shower, wash your hair, wear loose clothing, do not wear jewelry, and turn off your cell phone during the examination.
CT or magnetic resonance imaging (MRI) of the lumbar spine and pelvis
Purpose of the examination: It can discover and determine the causes of the disease and assist in the formulation of treatment plans.
Significance of the examination: It can discover the causes of lumbar disc herniation, pelvic tumors, infections and stones.
Precautions: Remove metal from the body before examination; CT examination is prohibited for women in preparation for pregnancy and pregnant women; MRI is prohibited for those who have pacemakers and metal implants in the body.
Differential Diagnosis
Sciatica
Sciatica will start from the lower back, the back of the thigh and radiate to the calf and foot, with sensory abnormalities, while lateral femoral dermatomyelitis is mainly found in the outer thighs, with numbness and ants crawling sensation usually not lower than the knee.
Femoral neuropathy
Femoral neuropathy involves motor, sensory and autonomic nerves at the same time, and is mainly characterized by decreased or absent pain sensation in the anterior medial thigh and medial calf, and weakness in knee extension, which may be accompanied by neurotrophic changes such as edema and bruising in the lower limbs.
Lumbar plexopathy
Sensory abnormalities in lumbar plexopathy usually occur in the lateral, anterior and medial sides of the thighs and may extend down to the medial side of the calves, in addition to quadriceps, iliopsoas, and adductor magnus muscles weakness, and decreased strength in hip flexion and knee extension.
Treatment
Treatment purpose: actively treat the primary disease, release the pressure and stimulation to the nerves, improve the symptoms, and improve the quality of life.
Treatment principle: medication is the main treatment, together with rehabilitation therapy, nerve block and surgery if necessary.
General treatment
Avoid the use of belt, hernia belt, abdominal belt, etc.
Reduce weight for overweight or obese people.
Posture correction for those who have bad posture habits.
Actively treat infections, poisoning, tumors and other primary diseases, and control blood sugar.
Drug treatment
Nutritional nerve, anti-inflammatory and analgesic drugs should be used.
Nutritional nerve drugs
Vitamin B1 and methylcobalamin are often used.
They can nourish the nerves, thus promoting the regeneration of nerve axons.
Precautions: Start with a small dose and increase the dosage according to age and symptoms. Allergic to methylcobalamin is prohibited.
Anti-inflammatory drugs
Dexamethasone, prednisone, etc. are often used.
It can reduce the permeability of capillaries, reduce exudation, edema and the release of inflammatory factors, play the role of anti-inflammatory and reduce swelling, often used by local injection.
Precautions: It should not be used for a long time and repeatedly to avoid blood sugar fluctuations and local infections.
Analgesic drugs
Ibuprofen, diclofenac sodium, gabapentin, carbamazepine, etc. are often used.
Precautions: Avoid prolonged and large doses to prevent gastrointestinal reactions and drug tolerance.
Physical factor therapy
Physical factor therapy can be used in conjunction with medication to accelerate blood circulation and improve nerve nutrition to achieve the therapeutic goal.
Commonly used methods: infrared therapy, laser therapy, direct current ion introduction, transcutaneous electrical stimulation of the nerves and intermediate frequency electrotherapy.
Nerve Block Technology
By injecting a mixture of local anesthetics around the femoral nerve, numbness and decreased sensation in the innervated area of the femoral nerve can be achieved to identify the diseased nerve, and at the same time, analgesic treatment can be accomplished. This treatment is done by a pain physician, therefore, patients need to visit the pain department.
Electrical nerve stimulation and ultrasound-guided localization help to improve the success rate of the operation.
Precautions: contraindicated in the presence of local or systemic infection, bleeding tendency, severe cardiorespiratory insufficiency, and allergy to local anesthetics.
Surgical treatment
Surgical treatment options such as neurotomy and release may be considered for those with intractable pain, recurrent episodes, and unsatisfactory results of conventional treatments, but very few patients need them.
Caution: There will be loss of sensation in the innervated area after surgery and there may be residual numbness.
Prognosis
Cure
The prognosis is good in most cases with prompt treatment.
However, if the disease is prolonged, even with treatment, permanent damage to the lateral femoral cutaneous nerve may result, leaving sequelae such as numbness of the skin and loss of sensation.
Harmfulness
Long-term symptoms such as skin numbness and sensory loss may affect daily work, life and sleep.
Persistent and recurrent symptoms may cause depression and anxiety.
Daily
Daily Management
Dietary management
Ensure a varied diet, if combined with diabetes, tumors and other diseases should be under the guidance of a doctor.
Diet should be light (less oil, less salt, less sugar), avoid eating a lot of spicy and irritating foods such as chili peppers and peppercorns.
Moderately increase the amount of food rich in B vitamins, such as animal offal, carrots, broccoli and so on.
Abstain from alcohol and wine.
Life management
Avoid excessive weight bearing for a long time, using too tight belt, hernia belt, abdominal belt, wearing tight jeans, etc.
Avoid prolonged exposure to cold and damp environments.
Reduce weight for those who are overweight or obese.
Correct posture if you have bad posture habit.
Disease monitoring
Actively detect the original disease, for example, diabetes, should take medication on time, regular testing of blood glucose, and adjust the blood glucose to within the normal range.
Pay attention to whether the discomfort on the outer part of the thighs is aggravated, whether the pain is worse, whether the skin on the outer part of the thighs loses its elasticity, and whether the sweaty hairs fall off.
Follow up with your doctor at the time he/she asks you to do so.
Prevention
Prevention mainly starts from preventing the original disease.
Avoid prolonged squeezing of the lower back, abdomen and anterolateral thighs.
Avoid overweight, exposure to cold and poor posture.
Pay attention to safety and avoid trauma.
Actively treat diabetes, tumors, infections and other diseases.