Chronic low back pain is an expensive benign condition in industrialized countries.1 In a literature review of 30 population studies of low back pain between 1966 and 1998, the prevalence of low back pain at any given moment ranged from 12% to 33%, 1-year prevalence ranged from 22% to 65%, and lifetime prevalence ranged from 11% to 84%.2 Mechanical causes may be either injury to lumbosacral muscles and ligaments, facet joint or sacroiliac joint arthropathy, or discogenic disease due to degenerative changes. Discogenic pain most commonly affects the lower back, buttocks, and hips and is thought to be related to injury and subsequent repair of the anulus fibrosus.3 Treatments vary widely, and should be individualized to the patient. If noninvasive modalities are preferred, many options exist such as oral analgesics,4 muscle relaxants,5 exercises,6 acupuncture,7 manipulation,8 or back school.9 Although data exist supporting the use of traction to widen the intervertebral space,10 reduce disc protrusion11 and intradiscal pressure,12 and improve motor evoked potentials13 and leg mobility,14 systematic reviews of clinical trials of traction for low back pain with or without sciatica have found that traction is probably not effective in improving pain, compared to placebo, sham or other treatments.15–20.
In general, traction can be delivered manually by the therapist via the weight of the patient through a suspension device,21 or by the patient pulling the bars at the head of the table while lying on a specially designed table with the pelvis secured.22 These types of traction can be difficult to standardize because of the patient’s as well as the therapist’s fatigue, or intolerance by the patient to the force or position.23,24 Additionally, the pull force is linear and may elicit the body’s proprioceptive response that triggers paravertebral muscle contraction, which may reduce the distractive effect.
Several axial decompression systems have been developed to overcome these drawbacks. These systems include the DRX9000 (Axiom Worldwide, Tampa, FL, U.S.A., approved by FDA in 2003), the VAX-D (VatTech, Inc., Palm Harbor, FL, U.S.A., approved by the FDA in 1996), and the Accu-Spina System (North American Medical Corporation, Aventura, FL, U.S.A.,
approved by FDA in 2000). Although some nonrandomized studies of motorized spinal decompression reported pain reduction,25–28 a systematic review of relevant randomized trials suggests that published data are too limited to determine whether vertebral axial decompression provides benefit to individuals with low back pain (over other nonsurgical treatments).29 The goal of this study was to perform a retrospective chart audit to assess outcomes of a sample of outpatients with discogenic low back pain of more than 12 weeks treated with a 2-month course of motorized spinal decompression via the DRX9000.