Diagnosis and treatment of odontoid fractures

  Dentate fractures are a common cervical spine injury, with a lethality rate of 4% to 11% and accounting for 10% to 20% of all cervical spine fractures. The dentate process originates from the central vertebral body and is named for its shape. The dentate process has an irregular anatomical pattern and a unique anatomical relationship with the atlantoaxial vertebrae, and belongs to the category of spinous bone in Chinese medicine.  Almost all patients have a clear history of trauma, such as car accidents, falls from heights, and falls on flat ground. Occipital and cervical pain is the most common symptom of a dentate fracture. Radiating pain in the region of the distribution of the greater occipital nerve, neck stiffness, restricted movement, head and neck instability, and a forced position are also seen. Patients often support their head with their hands. Upper extremity weakness and lower extremity stiffness or delayed myelopathy are seen in a subset of patients.  Patients with suspected dentate fractures are first examined with anterior-posterior, lateral and open-oral radiographs of the cervical spine. Due to the occlusion of the anatomical structures around the occipitocervical junction, radiographs are not sensitive to a portion of dentate fractures. Therefore, in patients with a high clinical suspicion of dentate fracture, CT thin-section scans with sagittal and coronal reconstruction of axial CT should be performed to avoid missing bony injuries of the upper cervical spine. In patients with nerve injury or based on the consideration of whether a dentate fracture is combined with atlantoaxial ligament injury, cervical MRI should be performed to assess the integrity of the transverse atlantoaxial ligament.  Dentate fractures are generally classified into three types (Anderson-D’Alonzo typing): Type I is an apical dentate fracture, which is an oblique avulsion fracture of the apical dentate ligament and the attachment of the pterygoid ligament on one side, and is less common.  Type II is a fracture involving the neck of the odontoid process and is the most common and unstable type of fracture, with forward or backward displacement.  Type III is a fracture that extends into the pivotal vertebral body with a large cancellous base below the fracture end, and the fracture line often involves the superior articular surface of the pivot on one or both sides.  Type IIA, or partial type III fractures, are comminuted fractures of the dentate base with free bone fragments; this subtype of fracture is referred to as type IIA.  The non-union rate of untreated or improperly treated dentate fractures is 42%-72%, and there is also potential atlantoaxial instability, which may lead to acute or chronic injury to the brainstem and spinal cord once displacement occurs, causing severe tetraplegia, respiratory dysfunction, and even death. Therefore, active and appropriate treatment should be taken according to the type, displacement and age of the fracture.  For any patient suspected of having a dentate fracture, the cervical spine should first be temporarily immobilized, usually with a stiff cervical collar, and kept immobilized during transport and examination.  <>: “The spinous bone, also known as the jade column bone, is the three sections of the neck bone behind the head. This bone was injured, a total of four evidence: one said from a high fall, resulting in the cervical bone into the cavity, and left and right still active, with the lifting of the rule of law. One said the injury, head down, with the end of the rule of law. A fall injury, left and right skewed, with the whole rule of law. A said fall injury, face up the head can not hang, or tendons long bone error, or tendons together, or tendons strong, bone with the head low, with push, end, continue, the whole four rule of law.”  For dentate fractures without displacement, Halo frame or cephalothoracic cast is generally used for 8-12 weeks. For displaced dentate fractures, cranial traction should be applied, gradually increasing the traction weight to about 3 kg, with the heaviest not exceeding 5 kg. For anterior dislocation, bi-directional head and neck traction is more likely to reposition the patient. During the traction process, bedside photos should be taken at any time to understand the repositioning situation to avoid excessive traction and danger. When the X-ray shows that the fracture is well repositioned, Halo frame or cephalothoracic cast should be fixed for 8-12 weeks under traction.  Surgical treatment 1. Anterior dentate screw fixation Indications: Dentate fracture type II and type IIA, especially for type II fractures with the following conditions: fracture separation displaced backward, or displacement >4mm, angle >30°, age >40 years, multiple injuries, and bone not healing even after conservative treatment.  Surgical objectives: restoration of anatomical sequence, direct compression and fixation of the fracture; preservation of atlantoaxial joint motion; early functional exercise.  2.Posterior atlantoaxial pedicle screw fixation and fusion Indications: Atlantoaxial fracture combined with atlantoaxial dislocation.  Purpose of surgery: to stabilize and fuse the atlantoaxial joint in anatomical position.  Third, Chinese medicine diagnosis and treatment “Medical Zong Jin Jian” also contains: “Where the doctor is in the presence of evidence, ask him or fall car horse b injury, or fall from a high place fracture, or hit heavy fall. Then ask whether the person is thinking about eating or not, or the limbs are not injured, but the spirit is not reduced, or the spirit is short, or can sit up and walk, or drowsy and silent, or the pain is more than, stasis agglutination, swelling and hard tendons. It is advisable to take Zijin Dan internally, apply Wan Ling cream externally, and wash with Haitongpi soup and moxibustion and iron to fix pain.” For dentate fractures without combined spinal cord injury, medicine should be administered according to the three stages of fracture identification.