Overview
The femoral nerve is composed of lumbar 2-4 spinal nerve roots and emanates from the lumbar plexus. The motor branch innervates the iliopsoas muscle, quadriceps muscle, suture muscle and part of the pubic bone muscle, making the hip flexion and knee extension; the sensory branch is distributed in the anterior and medial thighs, and the medial side of the knee to the calf. Femoral nerve palsy is a common disease in neurology, mostly caused by pelvic trauma, spinal tumor, iliac muscle abscess, cardiac catheter insertion and other injuries to the femoral nerve, but also by diabetes mellitus, nodular polyarteritis and other vascular diseases. The main clinical manifestations are weakness of knee extension and hip flexion, difficulty in walking, quadriceps atrophy, and sensory impairment of the anterior femur and medial calf. Mainly for the treatment of the cause of the disease, to release the factors of compression and injury is the key to the treatment of this disease.
Causes
1.Tumor
Tumor in pelvis, spinal cord tumor, spine tumor, retroperitoneal tumor, etc.
2.Surgery and trauma
Surgery in the groin area, pelvic trauma, cardiac catheter insertion and other injuries to the femoral nerve, etc.
3. Abscess or hematoma
Abscess or hematoma of lumbar major muscle, etc.
4.Others
Lower limb aneurysm, diabetes mellitus, lead poisoning, organophosphorus pesticide poisoning, improper position such as coma or anesthesia when the thigh is over-extended or externally rotated, etc. can cause femoral nerve injury.
Symptoms
Mainly manifested as hip flexion weakness, knee joint can not be straightened, walking difficulties, although can walk on the ground, but can not climb the ladder and get up from the sitting position, quadriceps atrophy, patella protrudes, knee reflex is weakened or disappeared, the front of the thigh, the calf and the inner side of the foot sensory deficits, the knee may have pain.
Examination
1. Physical examination
Positive femoral nerve pull test, weak or absent knee tendon reflex, atrophy of quadriceps muscle.
2. Electromyography
It may show neurogenic damage to the innervated muscles. Electromyography shows that the conduction velocity of the femoral nerve on the affected side slows down, wave amplitude decreases, and the latency of the F wave or H reflex is prolonged; the latency of SEP is prolonged, wave amplitude decreases, and the wave interval is prolonged. Electromyography of the innervated muscles of the femoral nerve showed a loss of nerve potentials, while the healthy side was normal.
3. Ultrasound and CT
It is important to clarify the etiology of the disease.
Diagnosis
1. Medical history
Commonly seen in adults, usually acute attacks, mostly unilateral. There are clear traumatic factors before the onset of the disease, such as the position of lithotomy surgery, which causes the nerve to be compressed or stretched by the inguinal ligament; the iliopsoas muscle or retroperitoneal hematoma compression.
2. Clinical manifestations
The affected limb is weak or unable to extend the knee and flex the hip; when walking, the healthy limb is stretched out first, and then the affected limb is dragged forward; it is unable to run and jump; the knee reflex is weakened or disappeared; and the sensation of the anterior part of the thigh in different ranges is diminished or disappeared.
3.Auxiliary examination
Electromyography shows neurogenic damage to the quadriceps muscle and prolongation of the end of femoral nerve motor latency. Compound muscle action potential wave amplitude is reduced. CT and color ultrasound examination of the injury site is meaningful to clarify the etiology.
Differential diagnosis
Lumbosacral radiculopathy: It is mainly characterized by weakness, pain, mild muscle atrophy of the lower limbs, and weakening or disappearance of Achilles tendon reflex and knee tendon reflex. However, sensory nerve conduction velocity and sensory nerve action potential amplitude are generally normal, and neurophysiological examination can help to differentiate.
Treatment
1. Treatment of etiology
Early removal of factors causing femoral nerve palsy, such as relieving compression and injury, is the key to treatment.
2. Other treatments
B vitamins, diprazole, adenosine triphosphate (ATP), galantamine and other drugs can be used in combination. In addition, physiotherapy, acupuncture and other treatments can be used as appropriate.
Prevention
1. Actively treat the primary disease.
2. This disease is mostly caused by fractures and joint dislocations caused by trauma, so when patients have injuries to the lumbosacral region, pelvis and hip joints, attention should be paid to checking the motor and sensory functions of the femoral innervation area.
3. In severe cases of this disease, atrophy of quadriceps muscle can occur, resulting in hip flexion and knee extension, therefore, promoting the recovery of contraction function of quadriceps muscle and preventing muscle atrophy is an important issue that should not be neglected.
4. Use rehabilitation equipment to assist in hip and knee movement.