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Atlantoaxial dislocation

Introduction
Cause
Examine
Diagnosis

Introduction

Introduction Axillary fracture and dislocation is a common type of upper cervical spine injury, accounting for about 50% of the upper cervical spine injury. The clinically seen atlas fracture and dislocation, the neurological symptoms are different, some died on the spot, and some have different degrees. High spinal cord injury, manifested as cranial nerve spasm, quadriplegia or incomplete paralysis and respiratory dysfunction, often need immediate assisted breathing, and some are only occipital neck pain and movement disorders, neurological symptoms are mild. It is precisely this type of patient that is the most common and potentially dangerous in clinical practice and should be highly valued and actively treated accordingly.

Cause

Cause

The atlantoaxial joints include:

(1) The lateral joint of the atlantoaxial joint is composed of the left and right atlas sub-articular surface and the superior articular surface of the pivotal vertebra.

(2) The anterior and posterior joints of the odontoid process are located in front of the odontoid process and between the dentate and odontoid anterior arch of the atlas and the transverse ligament of the atlas, forming two synovial cavities. The periorbital ligament and lamella of the atlantoaxial joint include the transverse ligament of the atlas, the ligament ligament, the ligament, the lamella, and the ligamentum flavum between the posterior arch of the atlas and the vertebral arch. 90% of the head's rotational movement occurs in this joint, which is not only flexible, but also has many ligaments around the occipital, atlas, pivot and other cervical vertebrae. When the skull is subjected to sudden flexion, most of the kinetic energy of the head is concentrated on the transverse ligament, and the dentate process is just at the center of it, forming a "cutting" external force that can cause the transverse ligament to break. In addition, the vertical violent effect of the atlas burst fracture (Jefferson fracture), the lateral displacement of the atlas and the vertebral arch fracture can also cause the transverse ligament tear. The transverse ligament is attached to the front of the two sides of the atlas and is combined with the anterior arch to form a fibrous structure, which surrounds and restricts the excessive movement of the odontoid, and protects the atlantoaxial stability. When the transverse ligament is damaged or broken, the atlantoaxial axis can occur. Dislocation or subluxation of the joint. This is a serious injury, often accompanied by spinal cord injury, which can be fatal immediately.

Examine

an examination

Related inspection

Bone and joint soft tissue CT examination of bone and joint MRI examination of the limbs and joints of the extremities

The clinical manifestations are mainly determined by the severity of the transverse ligament injury and the degree of anterior atelectal dislocation and whether it causes compression of the spinal cord. Local manifestations are mainly pain in the suboccipital and occipital neck, and the activity is limited. If spinal cord injury is combined, there are four situations:

(1) The respiratory center is timely and is deadly at the damage site.

(2) There is a transient nerve after the injury, which shows a short limb paralysis or limb weakness, but can be quickly improved and even restored.

(3) quadriplegia, incontinence and respiratory dysfunction, which is the most serious. If the timely and effective treatment is not obtained, the dislocation of the atlas is more serious, and the compression of the spinal cord is also intensified.

(4) Delayed neurological symptoms. The injury did not occur at the time and at the early stage, and gradually appeared as the head and neck activity increased.

The typical clinical manifestation of atlantoaxial dislocation is head and neck tilt. If the unilateral forward displacement, the head is tilted away from the affected side to the healthy side; neck pain and stiffness, occipital neuralgia and the like. Symptoms and signs of spinal cord compression rarely occur. Sometimes a tiny trauma can cause a rotation of the atlantoaxial joint. The head is in a rotational position, which replaces the movement of the atlas on the pivotal axis. The two can only have a little activity.

Diagnosis

Differential diagnosis

Congenital malformation dislocation. There is abnormal development in the neck of the occipital neck. After trauma, the acute dislocation of the atlantoaxial joint is more likely to occur than normal. In most cases, atlantoaxial instability occurs gradually after adolescence. Two common types: (1) segmental obstacles, manifested as occipital and atlantoaxial fusion into the neck 2 to 3 vertebral fusion; (2) odontoid hypoplasia.

Spontaneous dislocation. Adult cases are often secondary to rheumatoid arthritis, and children are often secondary to infection in the neck. The essence of atlantoaxial rotation fixation is old dislocation. Fielding (1977) refers to the atlantoaxial rotatory subluxation state that occurs after spontaneous or mild trauma. Later (1983) he also called the rotatory shift.

Pathological dislocation. Also for the slow dislocation, the difference from spontaneous dislocation is that there are osteoporotic lesions of the atlas and/or the atlas. In China, atlantoaxial tuberculosis is more common, and occasionally in atlantoaxial tumor or osteomyelitis.