Ankylosing means fusing together. Spondylitis indicates inflammation of the vertebrae. Ankylosing spondylitis is a severe, painful, chronic progressive condition involving inflammation of one or more vertebrae, which produces joint changes similar to those seen in rheumatoid arthritis. The starting point of this condition is most often at the sacroiliac joints; this where the low back pain and ankylosing spondylitis usually begins. Ankylosing spondylitis mainly affects the spine, but it can affect other peripheral joints and body organs, resulting in severe joint and back stiffness, loss of motion and deformity as the condition progresses. This condition may also be referred to as spondylitis, rheumatoid spondylitis, or spondylarthropathy. Conditions should be differentiated from the more common mechanical back pain. AS usually begins insidiously in the third or fourth decades and usually persists for longer than three months, and tends to be relieved by exercise.

Ankylosing spondylitis has no known specific cause. However, genetic factors seem to be involved. The majority of people with ankylosing spondylitis have a gene called HLA-B27. HLA-B27 is present in over 90% of white patients with AS, with similar high correlation other racial groups. There are false positives in approximately 70% of the general population. This gene may make people more susceptible to developing ankylosing spondylitis. A group of symptoms known as Reiter's Syndrome may also lead to this condition. These include iritis (or uveitis); and conjunctivitis which causes red, gritty and painful eyes. Moreover, people with Reiter's Syndrome also suffer from urethritis.

Symptoms of ankylosing spondylitis are intermittent and related to inflammation of the spine, joints, and other organs. Early signs and symptoms may include: pain and stiffness in the lower back, upper buttock area, hip, neck, or the remainder of the spine. The onset of pain and stiffness is usually gradual and progressively worsens over months. The symptoms of pain and stiffness are: worse in the morning or after prolonged periods of inactivity; eased by motion, heat and a warm shower in the morning; and eased by a bent or stooping posture. Other signs and symptoms may include: restricted expansion of the chest due to involvement of the joints between the ribs; limited range of motion, especially involving the spine and hips, due to deterioration of bone and cartilage leading to fusion in the spine or peripheral joints; fatigue; low-grade fever; loss of appetite and weight loss; and possible involvement of the heart, lungs and eyes.

To diagnose this condition, a complete medical history and a thorough physical examination will be performed. Diagnostic tests for this condition would most likely include: spine or pelvis x-rays; computed tomography (CT) scans; or magnetic resonance imaging (MRI) scans. Blood tests may also be done to determine: the presence of the HLA-B27 gene; or the erythrocyte sedimentation rate (ESR), which is an indicator of inflammation, but not specific for condition.

The goal of treatment is to relieve pain and stiffness, and prevent, delay, or correct complications and spinal deformity. Treatment may include: Nonsteroidal anti-inflammatory drugs (NSAIDs) or disease modifying anti-rheumatic drugs. Physical and rehabilitation therapies may be instituted to maintain or restore spinal mobility, maintain or improve posture, and/or chest expansion. Surgery may also be indicated if pain or joint damage is severe.

Even with optimal treatment, some people will develop a stiff or "ankylosed" spine. Residuals may include deterioration at the site of the joint due to decreased mobility, and if treatment is not continued, permanent posture and mobility losses will occur. If there is involvement of the hip joints that progress to joint damage, total hip joint replacement may be necessary. There is no cure for ankylosing spondylitis. The fusion of joints that occurs is irreversible.

• The rating schedule for musculoskeletal was updated on February 7, 2021. Protection still does apply and should be considered with existing evaluations (38 CFR 3.951(a)).

• Evaluate under the General Rating Formula for Diseases and Injuries of the Spine for diagnostic codes 5235 to 5243 unless 5243 is evaluated under the Formula for Rating Intervertebral Disc Syndrome Based on Incapacitating Episodes.

• May be evaluated as an active disease process or based on loss of motion of the spine. If process is active, evaluate under 38 CFR 4.71a, DC 5009 (using the criteria in 38 CFR 4.71a, DC 5002 for the acute phase). If process is inactive, evaluate based on chronic residuals affecting the spine under 38 CFR 4.71a, DC 5003 or DC 5240, and separately evaluate other affected joints or body systems under the appropriate DC.

• Evaluate any associated objective neurologic abnormalities, including, but not limited to, bowel or bladder impairment, separately, under an appropriate diagnostic code.

• For VA compensation purposes, normal forward flexion of the cervical spine is zero to 45 degrees (see forward flexion-cervical spine), extension is zero to 45 degrees (see extension-cervical spine), left and right lateral flexion are zero to 45 degrees (see lateral flexion-cervical spine), and left and right lateral rotation are zero to 80 degrees (see lateral rotation-cervical spine). Normal forward flexion of the thoracolumbar spine is zero to 90 degrees , extension is zero to 30 degrees (see forward flexion-thoracolumbar), left and right lateral flexion are zero to 30 degrees (see lateral flexion-thoracolumbar), and left and right lateral rotation are zero to 30 degrees (see lateral rotation-thoracolumbar spine.) The combined range of motion refers to the sum of the range of forward flexion, extension, left and right lateral flexion, and left and right rotation. The normal combined range of motion of the cervical spine is 340 degrees and of the thoracolumbar spine is 240 degrees. The normal ranges of motion for each component of spinal motion provided in this note are the maximum that can be used for calculation of the combined range of motion.

• In exceptional cases, an examiner may state that because of age, body habitus, neurologic disease, or other factors not the result of disease or injury of the spine, the range of motion of the spine in a particular individual should be considered normal for that individual, even though it does not conform to the normal range of motion stated in Note (2). Provided that the examiner supplies an explanation, the examiner's assessment that the range of motion is normal for that individual will be accepted.

• Round each range of motion measurement to the nearest five degrees.

• For VA compensation purposes, unfavorable ankylosis is a condition in which the entire cervical spine, the entire thoracolumbar spine, or the entire spine is fixed in flexion or extension, and the ankylosis results in one or more of the following: difficulty walking because of a limited line of vision; restricted opening of the mouth and chewing; breathing limited to diaphragmatic respiration; gastrointestinal symptoms due to pressure of the costal margin on the abdomen; dyspnea or dysphagia; atlantoaxial or cervical subluxation or dislocation; or neurologic symptoms due to nerve root stretching. Fixation of a spinal segment in neutral position (zero degrees) always represents favorable ankylosis.

• Separately evaluate disability of the thoracolumbar and cervical spine segments, except when there is unfavorable ankylosis of both segments, which will be rated as a single disability.