Femoral nerve entrapment syndrome

　　1. Etiology

　　The disease is often caused by iliac oblique muscle strain during hip hyperextension movement.

　　2. Pathogenesis

　　The iliac oblique muscle is enveloped by the iliac oblique fascia, in the inguinal region, its posterior and lateral sides are the iliac bone, the medial side is the pubic tubercle ligament, and the front is the inguinal ligament. The fascia encloses the femoral nerve and the lateral cutaneous nerve of the thigh, forming a closed cavity. Below the inguinal ligament, the iliac oblique fascia thickens to form a fibrous arch, constituting a dense sheath. Any cause of iliac oblique muscle tear injury, causing edema and hemorrhage within the fascial sheath, can increase the tension under the fascia, thereby compressing the femoral nerve and the lateral cutaneous nerve of the thigh, leading to nerve entrapment syndrome. Common causes include iliac oblique muscle strain caused by hip hyperextension movement, injury due to strong contraction of the iliac oblique muscle, or mild injury leading to local hematoma in hemophiliacs. In addition, improper surgery can also lead to local scar compression of the nerve.

　　Commonly associated with femoral cutaneous nerve entrapment syndrome.

　　1. Most patients have a history of lumbar and gluteal sprains, twists, and more common in women.

　　2. Pain in the affected side of the buttocks,呈刺痛,酸痛或撕裂样痛, in the acute stage, the pain is severe, and there is also a pain in the thigh that extends beyond the knee, with symptoms of numbness and pain in the lower limbs, the pain is deep and the area is blurred, and there is no obvious demarcation line.

　　3. Patients often find it difficult to sit up, when changing from a sitting position to an upright position or from an upright position to a sitting position, they feel that they cannot use their lower back and leg strength, the pain worsens, and they cannot sit up directly. They need to support themselves with their hands or be supported by others to sit up.

　　4. Limited bending, the lifting of the lower leg on the affected side is limited, but there are no signs of nerve root irritation.

　　Patients who develop the disease after trauma often have an acute onset and gradually worsen. The progression of the disease is related to the urgency of iliac muscle hemorrhage. The patient first reports pain in the iliac fossa on the affected side, the hip cannot be extended, presenting in an abduction and external rotation position. This is often caused by increased tension in the iliac muscle, leading to muscle spasm. At this time, a mass or fullness can be felt on the iliac fossa on the affected side, and there is marked tenderness above the inguinal ligament. There is also tenderness in the lower abdomen. Neurological symptoms often appear several hours after the injury and are related to the degree of increased pressure within the fascial sheath. Initially, there is numbness from the anterior and medial aspect of the thigh to the knee and the anterior and medial aspect of the lower leg. Later, the patient reports weakness in extending the knee, the patellar reflex becomes weak and then disappears, the quadriceps muscle gradually becomes weak and paralyzed, and muscle atrophy occurs. This syndrome often occurs concurrently with femoral cutaneous nerve entrapment syndrome, with sensory disturbances in the lateral skin of the thigh.

　　There is currently no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of the disease. The current treatment, in addition to nerve nutrition drugs, can use traditional Chinese medicine to enhance and improve the local blood circulation of the nerve injury, and use nerve regeneration drugs to excite and activate the nerve cells after surgery to restore the function of the lower limbs. When exercising, you need to use orthopedic shoes to protect the ankle joint to prevent the occurrence of wear and tear foot deformities, bone wear, and foot varus deformity leading to severe disability.

　　In the process of diagnosis, in addition to relying on its clinical manifestations, auxiliary examinations are also needed.

　　1. Check coagulation factor VIII (FⅧ) to exclude hemophilia.

　　2. X-ray examination often shows no positive findings, and MRI examination can be performed to help with diagnosis.

　　This disease seriously affects the patient's daily life, so it should be actively prevented.

　　Foods that are good for the body for femoral nerve entrapment syndrome: Pay attention to a light diet, eat more vegetables and fruits, and reasonably match the diet. Eating foods rich in high protein is beneficial for wound healing. Supplementing a variety of vitamins, eating more fresh vegetables and fruits. You can eat various lean meats, milk, eggs, and other protein-rich foods. Avoid thick and spicy foods, and avoid foods that are prone to allergic reactions and irritation, such as fish and shrimp, strong tea, coffee, and alcoholic beverages.

　　1. Treatment

　　The recovery of nerve function is closely related to the timing of decompression. If the decompression is not timely, the compression time of the nerve is long, and the recovery may be incomplete or not recoverable; timely and thorough decompression can completely restore nerve function. However, it is necessary to make a clear diagnosis before surgery. If the patient has hemophilia, it is not advisable to perform surgical decompression and should actively perform hemostasis, analgesia, and protect the function according to the treatment principles of hemophilia. Hemostasis mainly relies on fresh blood transfusion or freeze-dried human coagulation factor VIII (antihemophilic globulin) to supplement the deficient coagulation factor VIII and IX. Compression wrapping and cold compressions also help with hemostasis, but attention should be paid not to wrap too tightly to avoid excessive pressure and cause tissue damage. Elevating the affected limb and traction can not only relieve pain but also reduce bleeding.

　　For patients without hemophilia, perform nerve decompression surgery under epidural anesthesia or general anesthesia. The patient lies on their back, and a diagonal incision is made from the lower abdomen to the midpoint of the inguinal ligament along the medial side of the iliac crest, 2 to 3 fingerbreadths away, and a 3 to 4 cm longitudinal incision is made vertically downward to the midpoint of the inguinal ligament. Cut the skin, separate the external oblique muscle and fascia along the direction of the muscle fibers of the external oblique muscle, and cut the fibers of the internal oblique muscle and transversus abdominis along the incision direction. Wrap the fingers with saline gauze, gently push the peritoneum towards the midline, and expose the iliac muscle and its fascia and the prominent mass. When cutting the fascia of the iliac muscle, do not damage the nerves that have been displaced by the mass. Remove the hematoma, and cut the iliac fascial sheath below the inguinal ligament along the sciatic nerve. Pay attention not to damage the medial femoral vascular bundle. At this time, the sciatic nerve is completely exposed. Perform external decompression of the nerve, remove blood clots, scars, and other compressive substances. If the nerve is deformed due to compression or has a hard feeling when touched, carefully cut the perineurium with a sharp knife under the surgical microscope. Perform perineurial decompression, there is no need to suture the muscle fascia sheath, suture the inguinal ligament in place, place a negative pressure drain in the incision, and suture the muscle layer and skin in layers. After surgery, elevate the affected limb, remove the negative pressure drain within 48 hours. After the suture is removed, physiotherapy conducive to the recovery of the sciatic nerve should be performed, and regular follow-up should be conducted.

　　2. Prognosis

　　Timely and thorough surgical decompression can completely restore nerve function. Otherwise, the recovery may be incomplete or not recoverable.