Hand nerve injury

　　1, Sharp injury:Cuts caused by knives, glass, etc., often occur in the hand, wrist, and elbow, causing complete or incomplete rupture of the digital nerve, median nerve, or ulnar nerve. If the wound contamination is not heavy and the incision margin is tidy, it should be tried to debride and repair the nerve as soon as possible.

　　2, Laceration injury:Blunt trauma such as contusions, machine injuries, etc., can cause nerve rupture or even a segmental nerve defect, the wound is often irregular, and the soft tissue injury is relatively severe. If the contamination is not heavy, debridement can be considered within 6 hours, otherwise, it is advisable to leave for secondary treatment.

　　3, Firearm injury:Gunshot or shrapnel wounds often accompany open fractures. High-speed shrapnel passing through soft tissue causes relatively extensive soft tissue damage; especially the wound channel of blast injuries is severely contaminated, early debridement should be performed, but the wound should not be sutured, and the nerve should be covered with healthier muscle for secondary repair.

　　1, Fracture or dislocation combined with nerve injury is very common, mostly caused by displacement of the fracture ends compressing the nerve. Nerve traction injuries can also occur during fracture dislocation or manual reduction, and sharp bone ends can sometimes pierce the nerve.

　　2, Nerve paralysis often occurs during ischemic contracture, and if the pressure is relieved in time, partial or complete recovery can be expected. If delayed too long, severe permanent paralysis may occur.

　　The muscles involved in the flexion and extension of the wrist and fingers, as well as the branches of the nerves that innervate them, are all located at the proximal end of the forearm. Injuries to the median, ulnar, and radial nerves at the proximal end of the forearm and the elbow can lead to dysfunction of flexion and extension of the fingers; when hand trauma occurs, it often involves the distal end of the forearm and the wrist, in addition to the radial nerve only causing hypoesthesia of the thenar eminence, injuries to the median and ulnar nerves can lead to dysfunction of the internal muscles of the hand and important sensory disturbances of the hand, mainly manifested as:

　　1, Median Nerve

　　Paralysis of the abductor pollicis brevis muscle leads to the dysfunction of thumb abduction and the dysfunction of pinching objects between the thumb and index finger, the radial side of the palm, the radial side of the thumb, index, middle, and ring fingers, the metacarpophalangeal joint of the thumb, and the proximal interphalangeal joints of the index, middle, and ring fingers on the radial side of the hand, with sensory disturbances beyond the proximal interphalangeal joints, mainly manifested as the loss of sensation in the index finger.

　　2, Ulnar Nerve

　　Paralysis of the interosseous and digital flexor muscles leads to a ring, claw-like hand deformity, that is, hyperextension of the metacarpophalangeal joints and flexural deformity of the interphalangeal joints; the Froment sign caused by paralysis of the abductor pollicis brevis muscle, that is, when the index finger is forced to point towards the thumb, the proximal interphalangeal joint of the index finger is明显屈曲, the distal interphalangeal joint is hyperextended, and the metacarpophalangeal joint of the thumb is hyperextended, with flexural deformity of the interphalangeal joints; as well as sensory disturbances in the ulnar side of the palm, the ulnar side of the ring finger, and the palmar side of the little finger, the ulnar side of the back of the hand, and the back of the ulnar half of one finger, mainly manifested as the loss of sensation in the little finger.

　　3. Radial nerve

　　The radial nerve has no motor branches below the wrist, and it only manifests as sensory disturbances in the radial side of the back of the hand and the proximal interphalangeal joints of the radial side of the three and a half fingers, mainly manifested as local sensory减退 or disappearance on the dorsal side of the thenar eminence.

　　4. Nerve injury of the palm and fingers

　　Commonly affects the median nerve and the digital proper nerve, which can cause sensory dysfunction on the adjacent sides of two fingers or on one side of a finger.

　　After the fixation is removed, it is best to perform functional exercises as much as possible and辅以 physical therapy. Functional exercises and local physical therapy have certain effects on promoting nerve regeneration and preventing muscle atrophy.

　　The recovery of neural function is very important for the function of the hand. Before the sensation of the hand is restored, special attention should be paid to the protection of the injured limb to prevent burns or frostbite, as the wound is difficult to heal once it occurs. In the early stage of sensation recovery, hypersensitivity is usually present, which will gradually disappear as the regenerating nerve develops and matures over time.

　　Preventing hand injuries should be the most critical measure.

　　The diagnosis of hand nerve injury mainly relies on clinical manifestations. When there is hand trauma, it often involves the distal end of the forearm and the wrist. In addition to the radial nerve causing only the sensory减退 of the thenar eminence, median and ulnar nerve injuries can lead to dysfunction of the internal muscles of the hand and important sensory disturbances of the hand. X-ray examination shows no positive findings.

　　In addition to the conventional treatment for hand nerve injury, attention should also be paid to some aspects of diet, such as eating light and reasonable dietary搭配. Avoid eating刺激性食物 such as cigarettes, alcohol, coffee, strong tea, and various spicy seasonings such as scallion, ginger, garlic, chili, pepper, curry, etc.

　　1. Treatment

　　Principally, the earlier the repair of hand nerve injury, the better the functional recovery. As long as the nerve injury is relatively mild, the distal ends are relatively整齐, with no obvious defects; the skin coverage is good, the wound contamination is light, and it is estimated that there will be no infection after debridement, direct suture should be performed immediately in the first stage. The main method for repairing hand nerves is nerve suture (including epineurial suture and perineurial suture). Generally speaking, epineurial suture is used when the nerve trunk is injured, while perineurial suture should be used when the sensory and motor branches of the nerve can be separated, such as in the case of ulnar nerve injury at the wrist, the deep and superficial branches of the ulnar nerve can be separated, and sutured separately by perineurial suture. When suturing nerves, if there is tension, appropriate free the distal ends of the two nerves, change the position of the joint (such as flexing the wrist joint when suturing the median nerve), and perform nerve transfer (such as in the case of posterior elbow ulnar nerve rupture, the two distal ends of the ulnar nerve are moved to the anterior elbow, and the nerve is sutured in the flexed elbow position. At this time, it is absolutely not allowed to suture the ulnar nerve in situ at the posterior elbow joint, and to fix the elbow joint for a long time in the extended position, affecting the functional recovery of the elbow joint). Even if the nerve defect is too large and it is really impossible to suture directly, if the local soft tissue condition is good, a primary nerve graft can still be performed. To avoid the sensory loss caused by nerve removal from the donor site, the distal end of the removed nerve can be sutured to the adjacent normal nerve trunk using end-to-side anastomosis, so that the nerve fibers regenerate through the collateral branches of the normal nerve trunk, and restore its sensory function.

　　When the nerve is partially damaged, the undamaged part should be carefully separated and protected, and the damaged part should be debrided and sutured.

　　After the operation, the affected limb should be properly fixed with a plaster splint to keep the sutured nerve in a relaxed position, which is conducive to its healing. The fixation time is generally 4-6 weeks, depending on the tension at the time of suture. Antibiotics should be appropriately used to prevent infection, and neurotrophic drugs should be appropriately used to promote nerve regeneration.

　　After the fixation is removed, it is best to perform functional exercises as much as possible and辅以 physical therapy. Functional exercises and local physical therapy have certain effects on promoting nerve regeneration and preventing muscle atrophy.

　　The recovery of neural function is very important for the function of the hand. Before the sensation of the hand is restored, special attention should be paid to the protection of the injured limb to prevent burns or frostbite, as the wound is difficult to heal once it occurs. In the early stage of sensation recovery, hypersensitivity is usually present, which will gradually disappear as the regenerating nerve develops and matures over time.

　　2. Prognosis

　　The effect after sensory nerve anastomosis is acceptable, but the effect after motor nerve anastomosis is poor.