Common Peroneal Nerve Injury

　　The common peroneal nerve is a branch of the sciatic nerve. Since the common peroneal nerve is located at the neck of the fibula, it is superficial, on the surface of the bone, and surrounded by few soft tissues, with poor mobility, it is easy to be injured at this location. Such as injury by splint, plaster, or surgical error; it is not uncommon for knee ligament injury to be accompanied by injury to the common peroneal nerve; in critically ill patients who have been lying in bed for a long time, the lower limb in an external rotation position can also be injured.

　　It can be accompanied by pathological changes such as foot inversion and downward drooping, initially with abnormal soft tissues, contraction of the medial foot muscles, increased tension, thickening of the joint capsule, ligaments, and tendons, with the 'tarsal interosseous joint' as the center, leading to deformity of the anterior part of the foot:

　　1. Adduction of the tarsal joint.

　　2. Plantar flexion of the ankle joint.

　　3. Inward and downward inversion of the anterior part of the foot.

　　4. Slight inward and downward drooping of the calcaneus.

　　With the increase of age, the deformity becomes more serious, the tendons of the Achilles, posterior tibial, long flexor of the toe, and long flexor of the thumb become extremely contracted with strong elastic resistance; the soft tissues on the lateral side of the foot and muscles are continuously stretched and extended; the function of foot abduction is basically lost, but the muscle nerve function is intact, and the muscle excitability still exists.

　　The injury to the common peroneal nerve can cause paralysis of the anterior and lateral extensor muscles of the lower leg, with foot dorsiflexion and inversion dysfunction, presenting as foot drop deformity. As well as the loss of extension of the thumb and toe, presenting in a flexed state, with sensory disturbances in the anterior and lateral lower leg and the front and medial side of the top of the foot.

　　Prevention of injury to the common peroneal nerve should be emphasized, such as adding padding protection behind the head of the fibula before applying plaster or splint, and preventing injury to the common peroneal nerve during surgery at the popliteal fossa or head of the fibula. Avoid trauma, with prevention as the main approach. Patients with foot drop and inversion may twist the outer ankle slightly during walking, so patients should be educated to prevent secondary injury.

　　Injuries to the common peroneal nerve are often caused by trauma, mainly manifested as foot drop and a gait with a leaping step; the ankle joint cannot be dorsiflexed or inverted, and the toes cannot be dorsiflexed; the skin sensation on the lateral side of the lower leg and the top of the foot is reduced or absent; there is muscle atrophy in the anterior tibial and lateral lower leg muscles. So, what examinations should be done after the injury to the common peroneal nerve? The following experts introduce the examinations that need to be done after the injury to the common peroneal nerve:

　　1. Electrophysiological examination

　　The conduction velocity of the common peroneal nerve on the affected side is slowed down, the amplitude decreases, and the latency of F wave or H reflex is prolonged; the latency of SEP is prolonged, the amplitude decreases, and the interwave period is prolonged; electromyography of the muscles innervated by the common peroneal nerve mostly shows denervated potentials.

　　2. Ultrasound examination

　　Can accurately display peripheral nerves, especially the common fibular nerve, can provide imaging data for clinical diagnosis and treatment, and can provide reference for surgical treatment plans.

　　The common fibular nerve runs diagonally from the back of the popliteal fossa along the inner edge of the biceps femoris, passes between the two heads of the long head of the fibula, and then divides into the superficial and deep nerves. Scientific and reasonable diet has a great help in the rehabilitation of common fibular nerve injury. Then, what are the dietary requirements for patients with common fibular nerve injury? The following experts introduce the dietary taboos for patients with common fibular nerve injury:

　　1. Patients with common fibular nerve injury should eat foods rich in choline and vitamin B12, such as soy products, eggs, peanuts, walnuts, fish, meat, oatmeal, millet, kelp, red fermented bean curd, stinky tofu, Chinese cabbage, and radishes, etc.

　　2. Patients with common fibular nerve injury should eat more oatmeal.

　　3. Light and nutritious foods such as longan and jujube soup, lean meat, eggs, fish, etc., because such patients often have insufficient Yin and blood; for those who are overweight, it is advisable to have a light diet, eat more fresh vegetables and fruits, such as celery, sprouts, cucumbers, bananas, oranges, etc.

　　4. Patients with common fibular nerve injury should avoid stimulants such as coffee, soda, and cigarettes.

　　Pay attention to prevention, such as adding pads to protect the back of the fibula before casting or splinting, and preventing the common fibular nerve injury during surgery at the popliteal fossa or fibular head. The common fibular nerve injury should be treated as soon as possible, and most can be repaired by direct nerve anastomosis. If the nerve defect is too large, consider using autologous gastrocnemius nerve transplantation for repair. Clinical treatment shows that the effect of surgery within 3 months after the injury is the best. Closed fibular nerve injury, although there is a possibility of spontaneous recovery, should also be explored as soon as possible, and perform release surgery, anastomosis or nerve transplantation surgery. If there is no recovery, transfer the posterior tibial muscle or perform a three-joint fusion surgery to improve function. Sensory disturbance is not in the weight-bearing area and does not need to be treated.