Hanging fracture or traumatic odontoid process fracture

　　1. Etiology

　　It is often caused by neck extension force.

　　2. Pathogenesis

　　The force direction of this type of fracture often comes from the mandible, causing the cervical spine to extend backwards. The skull may be directly impacted by the posterior arch of the first cervical vertebra, and the force is transmitted to the posterior arch of the second cervical vertebra, forming a strong shearing stress at the root of the second cervical vertebra arch. When this exceeds the local bone bearing load, it causes fractures at this location. At this time, if the extension force continues to act, it will successively cause the anterior longitudinal ligament of the neck 2-3 vertebral segments to break, the vertebral space in front to separate, resulting in increased compressive stress on the atlas, and fractures may occur, ultimately causing high-level cervical cord injury and affecting the vital center, leading to rapid death. This is the whole process of hanging. Of course, asphyxia caused by the rope tied around the neck and carotid sinus reflex are also one of the main causes of death. Currently, this type of fracture is mainly seen in traffic accidents on expressways (neck overextension during emergency braking) and high-altitude diving accidents. The mechanism of occurrence is different from that of hanging: the former has both extension force and compression force from the posterior part of the vertebral segment during the injury process, while the latter is a divided force.

　　Spinal cord injury refers to the injury of the spinal cord caused by direct or indirect external factors, resulting in various motor, sensory, and sphincter dysfunction, abnormal muscle tone, and pathological reflexes at the corresponding segments. The degree and clinical manifestations of spinal cord injury depend on the location and nature of the primary injury. In traditional Chinese medicine, it belongs to the category of diseases such as 'lumbago', 'flaccidity', and 'enuresis' caused by external trauma and blood stasis. The degree and clinical manifestations of spinal cord injury depend on the location and nature of the primary injury.

　　Currently, the classification of hanging fracture is still based on the method proposed by Levine and Edwards in 1985.

　　One, type I

　　It is bilateral pedicle fractures, the fracture line is located in front of the zygapophyseal joint, mainly causing separation between the second cervical vertebral body and the posterior zygapophyseal joint, lamina, and spinous process, with an interval of about 2mm (1-3mm) between them. Generally, it does not form pressure on the spinal cord tissue within the vertebral canal, so there are few cases of simultaneous spinal cord injury.

　　Two, type II

　　It is based on the former, with further increase in violence, not only the fracture is separated, but also accompanied by angular deformity; rupture of the anterior or posterior longitudinal ligament, or both are ruptured; the posterior inferior margin of the C2 vertebral body may be torn off by the posterior longitudinal ligament, resulting in avulsion fracture, and the degree of separation of the fracture end is greater than that of the former, generally more than 3mm, or the angular deformation is greater than 11°.

　　Three, type III

　　It is more serious than type II injury, not only the anterior and posterior longitudinal ligaments are ruptured simultaneously, but the degree of malalignment of the fracture of the anterior aspect of the bilateral zygapophyseal joints is more obvious, even showing the state of vertebral segment dislocation. At this time, it is generally accompanied by rupture of the intervertebral disc and annulus fibrosus, and there are three sites of injury at C2:

　　1. Fracture of the pedicle or lamina of the vertebra.

　　2. Bilateral zygapophyseal semi-dislocation or dislocation.

　　3. Rupture of the anterior and posterior longitudinal ligaments, causing semi-dislocation or dislocation of the C2 vertebral body.

　　1. New employees must undergo pre-job training before going on duty, teaching them the use of relevant instruments and equipment as well as necessary production and protection knowledge, strictly abide by the operational procedures, and carry out necessary exercises and practice to make them proficient in operation procedures.

　　2. Continuously improve technology, adopt advanced process technology, regularly inspect and maintain machinery and equipment, eliminate the psychology of carelessness, establish the concept of 'safety first' during the work process, and wear personal protective equipment such as safety helmets and protective glasses when on duty.

　　3. Prohibit drinking for jobs that can interfere with attention, such as drivers and machine tool maintenance. It is worth mentioning that some drugs can cause drowsiness and other side effects, which often cause inattention. Therefore, it is cautious to take medication at work when feeling unwell.

　　4. Strengthen nutrition, actively participate in physical exercise, improve physical fitness, correctly handle interpersonal relationships, and do not bring unpleasant emotions from family and work into production. Although it is difficult to do, it is extremely important for preventing accidents such as industrial injuries.

　　5. Reasonably arrange the work and rest system of employees, pay attention to the combination of work and rest, ensure adequate sleep, and avoid overfatigue.

　　One, what kind of food is good for the body for hanging fracture or traumatic odontoid arch fracture of the atlas

　　1. It is recommended to eat more vegetables rich in fiber, and eat bananas, honey, and other foods that promote gastrointestinal digestion and defecation.

　　2. In the early stage, it is recommended to eat foods that promote blood circulation, remove blood stasis, and dissipate Qi, such as vegetables, soy products, fish soup, eggs, etc.

　　3. In the middle stage, it is recommended to eat foods that help and relieve pain, remove blood stasis, and promote the growth of new tissues, such as bone soup, Cordyceps chicken, animal liver, etc.

　　4. In the later stage, it is recommended to eat more foods that nourish the liver and kidneys, invigorate the Qi and nourish the blood, and relax the tendons and collaterals, which can help the formation of callus, such as old hen soup, pork bone soup, sheep bone soup, etc.

　　II. What foods should be avoided for clavicular fractures or traumatic odontoid process fractures of the atlas?

　　1. Avoid blind supplementation of calcium.

　　2. Avoid indigestible foods.

　　3. Avoid eating too much meat and drinking bone soup.

　　I. Treatment

　　1. General cases refer to fractures without obvious displacement or easy to reduce (most belong to stable type I), which can be immobilized with head-neck-thoracic plaster for 6-10 weeks after 2-3 weeks of bed traction. The head and neck should be in a forward flexed position during traction; however, for those with formed forward flexion, horizontal traction should be performed first, followed by slight extension. Head ring brace fixation can also be chosen.

　　2. For cases with obvious displacement of fractures, reduction should be performed first. Most cases are treated with posterior open reduction under direct vision, and posterior pedicle screw internal fixation surgery. It is also possible to perform anterior cervical open reduction and interbody fusion surgery between C2 and C3 vertebrae, including procedures such as CHTF fixation, cervical plate screw fixation, and bone graft fusion. After surgery, the cervical posterior pedicle clamp fixation surgery (C1-3) or other corresponding protective measures should be adopted according to the different effects of internal fixation; however, those who undergo bone grafting still need to be protected by maxillo-thoracic plaster for 6-8 weeks.

　　3. It is very rare to have cases of excessive traction. In fact, this is the critical state before the spinal cord tractional rupture. In treatment, early cases can be relaxed to restore to the original position; those over 3 months should take decompression + in situ fixation and fusion surgery.

　　4. Those with spinal cord injury are mostly cases with central syndrome, and they should be treated according to the type of injury.

　　II. Prognosis

　　Generally, the prognosis is good except for those with spinal cord injury, and there are few cases with residual sequelae.