Spondylolisthesis occurs when one vertebra slips forward in relation to the one below it, usually in the lumbar spine. If too much slippage occurs, the bones begin to compress the nerves and narrow the spinal canal. Segmental instability is an abnormally large motion at one or more spinal segments. It occurs when an applied force to the motion segment produces greater displacement than would occur in a normal spine.

Spondylolisthesis or segmental instability may be congenital or develop during childhood or later in life. They may result from physical stresses to the spine; weightlifting; sports injuries; or trauma. They may also be due to spondylolysis; or degeneration in the spine. Segmental instability can result from taking down the facet joints at the time of surgical decompression.

Symptoms of spondylolisthesis or segmental instability may include: pain in the lower back, thighs, and/or legs that may feel like a muscle strain; and weakness. Spondylolisthesis may cause spasms that stiffen the back and tighten the hamstring muscles, resulting in changes to posture and gait. In advanced cases of spondylolisthesis, some patients may appear swayback with a protruding abdomen, exhibit a shortened torso, and present with a waddling gait. Patients may be asymptomatic and learn of the condition from spinal x-rays.

Diagnostic tests for these conditions would most likely include: history and physical examination; spinal x-rays; computed tomography (CT) scan; or magnetic resonance imaging (MRI).

Conservative treatments may include rest; restriction of the activity causing stress; anti-inflammatory medications; analgesics; muscle relaxants; physical therapy; and/or a corset or brace. Surgery, such as spinal fusion, may be necessary to correct these conditions if too much slippage occurs and the bone begins to press on nerves; or if conservative treatments have failed to provide relief from the back pain and symptoms associated with spondylolisthesis.

Surgical treatment with spinal fusion of an unstable motion segment has a strong likelihood of improving symptoms. If the slippage has caused the bones to compress the nerves and narrow the spinal canal, removal of the obstruction usually gives patients some relief. However, regardless of treatment, if nerves were badly damaged, there may be some residual pain or numbness.

• 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.

• 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.

• See Plate V.