Posterior tibial nerve injury

　　The posterior tibial nerve descends vertically from the sciatic nerve and then下行 to the inferior border of the popliteal muscle at the middle line of the popliteal fossa, entering the deep surface of the gastrocnemius muscle. Since the posterior tibial nerve is located deep in the thigh and lower leg, the chance of injury is relatively rare. Sharp objects and penetrating injuries can injure the posterior tibial nerve and its main branches, often damaged between the malleolus and the Achilles tendon.

　　The main complications of posterior tibial nerve injury are high-arched feet and claw toes.

　　The main clinical manifestations of posterior tibial nerve injury are motor impairment and sensory loss, and long-term complications may include sole ulcers.

　　1. Motor impairment
　　The posterior tibial nerve innervates the muscles of the posterior lower leg and the sole of the foot. After injury, the foot cannot plantar flex and invert, resulting in a hammertoe deformity, making it difficult to lift the heel when walking and unable to walk fast. Paralysis of the intrinsic muscles of the foot causes deformities such as cavus foot and claw toe.

　　2. Loss of sensation
　　The area of sensory loss is the posterior lateral aspect of the lower leg, the lateral margin of the foot, the heel, and the plantar and dorsal sides of each toe, hence called the slipper-like paralysis area.

　　3. Foot ulcer
　　There are often ulcers on the sole of the foot, and the foot is prone to trauma, frostbite, and scalding. Often, due to ulcers, walking is difficult, which seriously affects function.

　　Posterior tibial nerve injury is mainly caused by trauma, so it is necessary to pay attention to prevent safety accidents in daily life.

　　The main examination for posterior tibial nerve injury is electromyography, which shows a decreased conduction velocity, reduced amplitude, and prolonged latency of F wave or H reflex on the affected side; prolonged SEP latency, reduced amplitude, and prolonged interwave period; electromyography of the muscles innervated by the posterior tibial nerve is mostly denervated potentials, while the healthy side is normal.

　　Patients with posterior tibial nerve injury should often eat foods rich in choline and vitamin B12, such as soy products, eggs, peanuts, walnuts, etc., which are beneficial to nerve recovery. It is advisable to eat light and nutritious foods, such as guilin and jujube soup, lean meat, eggs, fish, etc. Avoid stimulants such as coffee, soda, and cigarettes.

　　According to the condition of posterior tibial nerve injury, perform nerve decompression and decompression surgery, which generally has a good effect. The sensation of the sole is very important, and even partial recovery can help improve foot function and prevent and treat ulcers.

　　One, exposure of the tibial nerve in the popliteal fossa: Take a prone position. The surgical steps are as follows:
　　1. Incision: Slightly S-shaped, from the upper inside of the popliteal fossa (semitendinosus and semimembranosus), downward along the skin皱纹 of the popliteal fossa, turn outward and downward to the lower outside of the popliteal fossa at the lateral head of the gastrocnemius muscle, and then downward.
　　2. After slightly freeing the skin, pull it apart to both sides and longitudinally cut the deep fascia at the point where the small saphenous vein merges into the popliteal vein. Ligate the small saphenous vein if necessary. Separate along the interval between the biceps femoris and the semitendinosus and semimembranosus muscles at the upper part of the incision, and separate along the interval between the lateral and medial heads of the gastrocnemius muscle at the lower part, and then pull it apart to both sides. The common peroneal nerve descends along the posterior margin of the biceps femoris, and should be properly protected. The tibial nerve is relatively superficial, located on the lateral and posterior side of the vein. The popliteal artery is deeper, located on the anterior and medial side of the vein. After pulling the popliteal vein and the tibial nerve outward, the popliteal artery can be exposed.

　　Two, exposure of the tibial nerve in the lower leg: Take a supine position, with the affected limb in an external rotation position. The surgical steps are as follows:
　　1. Incision: Cut along the inner edge of the gastrocnemius muscle longitudinally with the affected area as the center, and can be extended up and down as needed.
　　2. Pull the great saphenous vein and saphenous nerve anteriorly and open the dense deep fascia along the inner edge of the gastrocnemius muscle. After pulling the gastrocnemius muscle backward, expose the gastrocnemius muscle and open along its inner edge. After pulling the gastrocnemius muscle and the soleus muscle backward, expose the vascular nerve bundle. The posterior tibial artery is on the medial side, the posterior tibial vein is close to the artery on the deep side, and the tibial nerve is on the lateral side of the artery. Carefully cut open the vascular nerve sheath and separate to expose the posterior tibial nerve.