Vertebral axial decompression therapy is a very useful tool for people who have horrible back problems because it is relatively inexpensive and it does not involve surgery. Data was collected from twenty-two medical centers for patients who received VAX-D therapy for low back pain, which was sometimes accompanied by referred leg pain. Only patients who received at least ten sessions and had a diagnosis of herniated disc, degenerative disc, or facet syndrome, which were confirmed by diagnostic imaging, were included in this study.

The data contained the patients' quantitative assessments of their own pain, mobility, and ability to carry out the usual 'activities of daily living'. The treatment was successful in 71% of the 778 cases, when success was defined as a reduction in pain to 0 or 1, on a 0 to 5 scale. Improvements in mobility and activities of daily living correlated strongly with pain reduction. The causes of back pain and their relationship to this therapy are also discussed.

Although imaging procedures, including CT and MRI, are able to accurately define structural pathology, the correlation of these anatomic findings with physiology, back pain, and other clinical complaints is imprecise. Although surgical decompression, epidural blocks, and spinal instrumentation can sometimes help patients suffering from back pain, these treatments do not completely take the biomechanical function of the disc into account, and may leave patients unrelieved of their suffering.

Low back pain is aggravated by activities that increase axial loading on the spine, such as sitting, standing, and lifting. Patients may describe some relief with walking, but more particularly, by lying down, which unloads the spine and reduces intradiscal pressure. The causes of mechanical low back pain may include degenerative disc disease, degenerative spondylosis with limitation of range of motion, facet arthropathy, relative lateral recess stenosis from a combination of the above, microenvironment presure changes affecting the thecal and epidural space from disc bulging, subligamentous and/or extruded herniation, and segmental instability.

A number of potential mechanisms are specifically addressed by the lumbar vertebral body separation achieved during therapy. With aging, disc desicction occurs, disc height is lost, and this process is accelerated with activities which produce high physical loading of the lumbar spine. Osteophytes develop along the anterolateral and posterior border of the vertebral bodies, and facet arthropathy increases as degenerative disc change advances . Normal vertebral body separation is lost as the disc degenerates. blood supply to the nerve roots of the cauda equina is sensitive to compression. Even at pressures of only 5-10 mmHg, the flow in over 20% of the venules was completely stopped. Flow in all the capillaries stopped at pressures between 20 and 50 mmHg. A pressure of 30 mmHg is slightly less than one pound per square inch, so solute transport is easily reduced. Even vertebral distractions of 1 or 2 mm per disc would reduce ligamental redundancy and help to restore canal/foraminal patency, reduce venous congestion and increase axoplasmic flow.