Epidemiologic studies suggest that back pain will affect more than 80% of the population at some point in their life. Chronic low back pain disability is the most expensive benign condition that is medically treated in industrial countries, costing the health care system more than $65 billion a year. Back pain is also the number one cause of disability in people under the age of 45 and is the third leading cause of disability in people over 45 years of age.

With recent advances in biotechnology, spinal decompression therapy has evolved into a cost-effective, nonsurgical treatment option for degenerative spinal disc disease. This treatment modality works on the affected spinal segment by significantly reducing intradiscal pressures and is an integral part of a comprehensive spinal rehabilitation program.

Disc Degeneration

The intervertebral disc is made up of an outer annulus consisting of 12 to 14 concentric rings of fibrocartilaginous material, which encapsulates the inner mucopolysaccharide gel nucleus. The intrinsic pressure of the fluid within the disc allows hydrodynamic activity, making the intervertebral disc a mechanical structure. As a person moves through normal ranges of motion, disc deformation occurs as a result of pressure changes within the disc. As the disc deforms, nuclear migration ensues along with and tensile loads to the annular fibers.

Cumulative trauma in the annular fibers and supporting structures can lead to biomechanical dysfunction and pathologic processes. Osteophytes (bone spurs) develop along the junction of vertebral bodies and discs, resulting in spondylosis. This disc narrows from the alteration of the nucleus pulposus, which changes from a gelatinous consistency to a more fibrous nature as the aging process continues. The disc space thins with sclerosis of the cartilaginous end plates and new bone formation around the periphery of the contiguous vertebral surfaces. The altered mechanics place stress on the posterior zygoapophyseal or facet joints, causing them to lose their normal movement. With the loss of disc space, the plane of articulation of the facet surface is no longer congruous. This stress results in degenerative arthritis of the articular surfaces.

When degenerative disc disease occurs, the layers of the annulus can separate in places and form circumferential tears. Several of these circumferential tears may unite and result in a radial tear where the material may herniate and produce disc herniation or prolapse. Even though a disc herniation may not occur, the annulus produces weakening, circumferential bulging, and loss of intervertebral disc height. As a result, discograms at this stage usually reveal reduced intradiscal pressure.

The early changes that have been identified in the nucleus pulposus and annulus fibrosis are probably biomechanical and relate to aging. Any additional trauma to these structures can speed up the process of degeneration. When there is a discogenic injury, physical displacement occurs, as well as tissue edema and muscle spasm, which increase the intradiscal pressures and restrict fluid migration. Additionally, compression injuries causing an endplate fracture can predispose the disc to degeneration in the future.

Clinical Presentation

The alteration of normal kinematics is the most prevalent cause of lower back pain and disc disruption and, as a result, it is vital to maintain homeostasis in and around the spinal disc. Medical studies have correlated this degeneration to clinical symptoms. The three clinical stages of spinal degeneration include:

1. Dysfunction Stage. There is little pathology and symptoms are subtle or absent. The diagnosis of Lumbalgia and rotatory strain are commonly used.
2. Instability Stage. Abnormal movement of the motion segment of instability exists and the patient complains of moderate symptoms with objective findings. Conservative care is used and sometimes surgery is indicated.
3. Stabilization Stage. The third phase where there are severe degenerative changes of the disc and facets reduce motion with likely stenosis.

Spinal Decompression Literature Review & Clinical Studies

Spinal decompression has been shown to decompress the disc space, and in the clinical picture of low back pain is distinguishable from conventional spinal traction. According to the literature, traditional traction has proven to be less effective and biomechanically inadequate to produce optimal therapeutic results. In fact, one study by Mangion et al concluded that any benefit derived from continuous traction devices was due to enforced immobilization rather than actual traction. In another study, Weber compared patients treated with traction to a control group that had simulated traction and demonstrated no significant differences. Research confirms that traditional traction does not produce spinal decompression. Instead, decompression, (i.e. unloading due to distraction and positioning of the intervertebral discs and facet joints of the lumbar spine), has been proven an effective treatment for herniated and degenerative disc disease, by producing and sustaining negative intradiscal pressure in the disc space. In agreement with Nachemon's findings and Yong-Hing and Kirkaldy-Willis, spinal decompression treatment for low back pain intervenes in the natural history of spinal degeneration.

Matthews used epidurography to study patients thought to have lumbar disc protrusion. With applied forces of 120 pounds over 20 minutes, he was able to demonstrate that the contrast material was drawn into the disc spaces by osmotic changes. Goldfish speculates that the degenerative disc may benefit by lowering intradiscal pressure, affecting the nutritional state of the nucleus pulposus. Ramos and Martin showed by precisely directed distraction forces, intradiscal pressure could dramatically drop into a negative range. A study by Onel et al reported the positive effects of distraction on the disc with contour changes by computed tomography imaging. High intradiscal pressures associated with both herniated and degenerated discs interfere with the restoration of homeostasis and repair of injured tissue. Gionis, et al demonstrated that 86% of the 219 patients who completed decompression therapy reported immediate resolution of symptoms, while 84% remained pain-free 90 days post-treatment. Physical examination findings showed improvement in 92% of the 219 patients, and remained intact in 89% of these patients 90 days after treatment.

Although long-term outcome studies are needed to determine if spinal decompression therapy prevents, or merely delays surgery, recent advances in technology suggest promising results are obtainable in the effective management of patients with disc herniation, sciatica, stenosis, and degenerative disc disease.

Contraindications

Spinal decompression therapy is not recommended for patients with the following conditions: osteoporosis, spondylolisthesis grade 2 and above, fractures, tumors, or congenital pars defects. Previous spinal surgery is not contraindicated unless hardware (screws, rods, cages, pins, etc.) has been implanted in the back.

Latest Technology

Unlike some spine decompression devices such as Vax-D, where the distraction forces are created nonspecifically through the entire lumbar spine, the some of the latest technology is able to provide specific decompression to the exact disc level that is diagnosed from physical examination and the appropriate diagnostic imaging studies. The angle of decompression to the affected level causes a negative pressure intradiscally that creates an osmotic pressure gradient for fluid transfer into the degenerated and/or herniated disc, thereby providing an optimal environment for healing to occur. In addition, units like the SpineMed decompression unit is safe and will not affect the integrity of the shoulder joints as is the potential with Vax-D treatment.

Conclusion

Spinal decompression therapy is not a panacea for the treatment of back pain, but is an integral part of a comprehensive back pain treatment program. In association with a back pain exercise program, appropriate spinal bracing, and spinal education, you will benefit from the latest evidenced based technologies for the treatment of back pain.