Overview
Ankylosing spondylitis (AS) is a chronic inflammatory spondyloarthropathy characterized by sacroiliac arthritis and mid-axis arthropathy, mainly manifesting as spinal and peripheral arthritis with varying degrees of ocular, pulmonary, cardiovascular and renal damage, and producing pain and progressive joint stiffness. The prevalence of AS varies from country to country, with a prevalence of approximately 0.26% in the Chinese population. The disease is more common in men, with a male-to-female ratio of 10-14:1. Some scholars believe that the prevalence in women is approximately the same as in men, except that women have a slower onset and less severe disease.
HLA-B27 (hereafter referred to as B27) is closely related to the development of AS and has a clear tendency to develop in families. According to epidemiological surveys, the rate of B27 positivity in AS patients is as high as 90%, while the rate of B27 positivity in the general population is only 4%-9%; the incidence of AS in B27-positive patients is about 10-20%, while the incidence of AS in the general population is 1%-2%, a difference of about 100 times. One of the hallmarks and early manifestations of AS is sacroiliac arthritis. The typical manifestation of spinal involvement in advanced stages is a bamboo-like spine. Synovitis of peripheral joints is histologically indistinguishable from rheumatoid arthritis. Terminal tendinopathy is one of the features of the disease. Focal mesangial necrosis of the aortic root can cause annular dilatation of the aorta as well as shortening and thickening of the aortic valve cusps, leading to incomplete aortic valve closure.
Clinical presentation
The disease has a slow and insidious onset. Early typical symptoms are insidious dull pain, usually deep in the lumbar and gluteal regions, which is apparent at night and is associated with lumbar immobility and significant morning stiffness, which improves with activity and recurs after rest. Within six months to a year of the onset of symptoms, patients may experience a gradual progression of symptoms up the spine, including the thoracic spine, and may experience respiratory distress. Generally, the cervical spine is the last to be involved in the spine, and the duration of the disease is generally about 10 years or more from the appearance of symptoms to the involvement of the cervical spine. When the lesion involves the cervical spine, the cervical spine and thoracic spine show a retroflexion deformity, and in severe cases, the lower jaw is close to the chest, and the patient can only see the ground under the feet and cannot see forward normally. A high percentage of vertebral fractures occur in AS, especially in the cervical spine, and 75% of patients develop neurological symptoms after cervical fracture; spontaneous atlantoaxial dislocation and atlantoaxial instability is another serious complication that has been reported in both adolescents and adults, unlike in patients with rheumatoid arthritis.
Peripheral arthropathy occurs in 24-75% of patients with AS at the beginning or during the course of the disease, mostly in the knee, hip, ankle, and shoulder joints, with occasional involvement of the elbow and small joints of the hand and foot. Asymmetric, few-joint or single-joint arthritis and arthritis of the large joints of the lower extremities are the characteristics of peripheral arthritis in this disease. In our patients, arthritis or arthralgia of the knee and other joints, except the hip, is mostly transient and rarely or hardly causes joint destruction and disability. The hip joint is involved in 38%-66% of cases, showing localized pain, restricted movement, flexion-twisting and joint ankylosis, most of which are bilateral, and 94% of hip symptoms start within the first 5 years after the onset of the disease. Younger age of onset and peripheral joints are more likely to develop hip lesions.
AS is a systemic disease that involves the spine and large joints in addition to the spine. Its extra-articular systemic diseases include: iridocyclitis, aortitis, cardiac conduction abnormalities, arachnoiditis, and cauda equina syndrome. And it is also associated with ulcerative colitis, restrictive enteritis, psoriasis, Reiter syndrome (non-gonococcal urethritis, combined with conjunctivitis and arthritis), Behcet syndrome (triad of oral, ocular, and genital syndromes with uveitis, retinal vasculitis, optic nerve atrophy, mouth sores, and genital ulcers), and multiple sclerosis.
Common joint symptoms of ankylosing spondylitis
Because of the insidious nature of AS, many patients often reach the middle or late stages of the disease by the time the disease is discovered, and because of the high disability rate of this disease, the common joint symptoms of AS are something you need to know more about.
Lumbar spine lesions: Patients will experience forward bending of the lumbar region, lumbar stiffness, and restricted movement, especially restricted bending. Physical examination mostly reveals lumbar spine spine pressure pain and lumbar paraspinal muscle spasm, which will be accompanied by lumbar muscle atrophy over time.
Thoracic spine lesions: back pain, anterior and lateral chest pain are the main manifestations of thoracic spine lesions in patients, and hunchback deformity is the most common. Patients have band-like chest pain with limited thoracic expansion, which is aggravated by inspiration, coughing and sneezing. In severe cases, the patient can only rely on abdominal breathing to assist.
Cervical spine lesions: Patients mainly present with cervical spondylitis, with pain in the cervical spine radiating along the neck to the head and arms. Subsequently, the neck muscles spasm and atrophy, and the lesion develops into a cervicothoracic retroflexion deformity. Head movement can only be fixed in a forward-flexed position, and those with severe disease are unable to raise their heads and look horizontally.
Sacroiliac arthritis: Patients have recurrent episodes of low back pain and lumbosacral stiffness, intermittent or alternating low back pain and hip pain on both sides, pain radiating to the thighs, and a negative extension and lifting test. Pain occurs with pressure or extension of the sacroiliac joint, although there are no symptoms of sacroiliac arthritis and abnormal changes on x-ray.
Diagnosis
The diagnosis of AS is mainly based on patient history, clinical manifestations and imaging examinations, and is not based on the histocompatibility antigen HLA-B27 antigen test, of which sacroiliac joint radiographs are an essential diagnostic procedure.
The commonly used clinical diagnostic criteria are the New York (1968) criteria, with the following main elements.
Clinical manifestations.
(1) Complete restriction of movement of the lumbar spine in all directions (forward flexion, back extension, lateral bending).
(2) A history of pain in the thoracolumbar or lumbar spine that is still painful.
(3) Thoracic expansion mobility measured between the four ribs, equal to or less than 2.5 cm.
There are five degrees of sacroiliac joint x-ray performance.
0 degree: normal.
I degree: suspicious.
Degree II (mild): limited erosion and sclerosis, no change in joint space.
Degree III (moderate): progressive sacroiliac arthritis with joint erosion, gap narrowing or partial fusion ankylosis.
Grade IV (severe): loss of joint space, joint fusion and ankylosis.
AS can be diagnosed by adding at least one of the above clinical indexes for III-IV degree bilateral sacroiliac arthritis, or by adding clinical indexes 1 or 2 or 3 above for III-IV degree unilateral or II degree bilateral sacroiliac arthritis. if the X-ray shows bilateral III-IV degree sacroiliac arthritis without the above clinical indexes, it should be diagnosed as suspicious AS.
The criteria were revised in 1984, and the revised contents are as follows.
1. Clinical diagnostic criteria.
(1) Low back pain and stiffness lasting for at least 3 months, with pain improving with activity, but not relieved by rest.
(2) Restricted movement of the lumbar spine in the anterior-posterior and lateral flexion directions.
(3) Thoracic mobility is reduced compared to normal people of the same age and sex.
2.Radiological criteria: bilateral sacroiliac arthritis ≥ grade II or unilateral sacroiliac arthritis grade III-IV.
Definite AS criteria: meeting radiological criteria and more than 1 clinical criteria.
Possible AS criteria.
(1) meeting 3 clinical criteria.
(2) Meeting radiological criteria but not any clinical criteria (except for other causes of sacroiliac arthritis).
For the early diagnosis of AS, Calin et al. proposed clinical screening criteria for AS in 1977, which were as follows.
(1) Low back pain or discomfort occurring before the age of 40 years.
(2) insidious onset.
(3) History of insidious back discomfort lasting more than 3 months.
(4) Morning stiffness.
(5) The above symptoms may improve with activity. In combination with family history and HLA-B27 examination, the diagnosis can be made if four or more of the above five criteria are met.
Treatment
The cause of AS is not fully understood, and there is no cure and no effective therapy to stop the progression of the disease. Many patients with sacroiliac arthritis progress to grade I or III and do not progress further, but only a few may progress to complete joint ankylosis.
1.Control the inflammation and reduce or relieve the symptoms.
2. Maintain normal posture and optimal functional position and prevent deformity. To achieve the above objectives, the key lies in early diagnosis, early treatment, and comprehensive measures for treatment.
The basic principles of AS treatment.
1.Early stage is based on non-surgical treatment.
2, the middle and late stages should actively prevent spinal deformity.
3, drug therapy for side effects of drugs should be strictly control the indications.
4, the deformity has affected the basic life, surgery should be considered to correct.
Non-surgical treatment
1.Disease knowledge education Make patients understand the nature of the disease, the course of the disease, the measures used and the prognosis. Inform patients about the correct posture and maintenance of normal activities in daily life, including sleeping with a thin pillow, taking a supine or prone sleeping position, and avoiding flexion. Adhere to labor and physical activities within their ability, and pay attention to posture at work to prevent spinal curvature deformity. Make patients understand the role and side effects of common therapeutic drugs.
2, functional exercise Functional exercise can maintain the physiological curvature of the spine to prevent hunchback deformity; maintain thoracic mobility to maintain normal respiratory function; maintain bone density and strength to prevent osteoporosis and limb wasting muscle atrophy. Including deep breathing, cervical spine exercise, lumbar spine exercise and limb exercise, swimming is the best whole body exercise as it is good for limb exercise and helps to increase lung function and keep the spine in physiological curvature. It should be noted here that patients should adopt the appropriate exercise mode and amount of exercise according to their personal conditions, and avoid excessive exercise.
3.Physical therapy Heat therapy can increase local blood circulation, relax muscles, reduce pain, facilitate joint movement and maintain normal function. Sunbathing can also be chosen to relieve pain, adjust the lesion process and relax the spastic muscles.
4.Drug treatment The drugs for AS can be divided into three categories.
(1) Drugs that inhibit disease activity and affect disease progression, such as sulfadiazine.
(2) Non-steroidal anti-inflammatory drugs are suitable for patients with pain and stiffness at night, and can be taken at bedtime, such as Fenbid, Mupirocort and Celebrex.
(3) Analgesics and muscle relaxants are often used for those who have been ineffective in long-term application of NSAIDs, such as prednisolone and myosoprine. In the acute stage, corticosteroids can also be used as adjuvant drugs for anti-inflammatory treatment.
5, brace protection: for those whose deformity develops faster, thoracic, dorsal and lumbar brace with definite effect should be used to fix it. Patients with cervical instability should also use a cervical brace to maintain the physiological curvature of the cervical spine to avoid neurological symptoms.
Surgical treatment
1.Surgical indications for hunchback deformity AS-induced hunchback deformity is a relatively common spinal disorder, and spinal osteotomy orthopedic surgery is the only effective treatment method. The indications for surgery are.
(1) Severe hunchback deformity, in which the knee and hip joints cannot be seen horizontally when they are straightened, which has affected the basic daily life.
(2) The lesion has become quiescent, meaning that the pain has disappeared for 1 year and the blood sedimentation is normal.
(3) Good general condition, cardiac and pulmonary function can tolerate surgery and anesthesia.
(4) Early surgery should be performed for patients with neurological involvement. Surgery for patients with hip ankylosis: When the hunchback and hip ankylosis are combined, the hip flexion deformity aggravates the upper part of the body, which has already shifted the center of gravity forward, and further increases the stress on the spine and hip joint. In order to effectively and accurately correct the hunchback, restore the normal stress characteristics of the spine, avoid the illusion caused by the anterior tilt of the spine that leads to the correction of excessive kyphosis and causes pronation; correct the insufficient angle of the hunchback; and correct the hunchback after the relapse caused by the anterior tilt of the spine and other complications, it is necessary to carry out orthopedic surgery for both parts. Since the longitudinal axis of the spine is tilted forward due to the ankylosis of the hip joint, the longitudinal axis of the spine must be made basically vertical in order to achieve more definite results in hunchback orthopedics. From the biomechanical point of view, it is reasonable to perform hip orthopedic surgery first and then correct the hunchback. Surgery for combined abdominal aortic calcification: Previously, abdominal aortic calcification was considered a contraindication to surgery because of the strong longitudinal pulling force during surgery, which could easily cause injury to the great vessels. The current surgery has been improved to avoid excessive longitudinal strain during spinal orthopedics.
The pathology of AS is characterized by bony ankylosis of the spine, vertebral osteoporosis and increased brittleness of vertebrae, so that spinal fractures can occur without external forces or with minor external forces. The posterior spinal deformity that often accompanies AS alters the biomechanical properties of the spine, with the vertex of normal kyphosis generally located at T7. The two long arms of the upper and lower force are the thoracic spine and rib cage at one end and the lumbar spine and pelvis at the other. The increase in kyphosis increases the stress on the vertex (often the thoracolumbar joint). These changes in spine biomechanics make AS spine fractures different from normal traumatic spine fractures and have their own characteristics.
(1) The trauma that causes an AS spine fracture is often mild, and sometimes the fracture can occur without even feeling the trauma.
(2) AS spine fractures often involve the anterior, middle, and posterior columns of the spine at the same time, and the chance of associated subluxation is higher, so they are often unstable fractures.
(3) Due to the presence of loss of cervical spine motor function, osteoporosis and progressive cervical kyphosis, AS spine fractures are most common in the lower cervical spine, followed by the thoracolumbar and lumbar spine, with a high incidence of respiratory complications in cervical fractures.
(4) AS thoracic spine fractures are often stress fractures with few nerve injuries, which are easily missed or misdiagnosed clinically. In patients with a long history of AS, if there is new or aggravated neck pain, thoracic back pain, or low back pain with a history of mild or severe trauma, a high suspicion of concurrent spinal fracture should be established.