A Prospective Randomized Controlled study of VAX-D and TENS for the
Treatment of Chronic Low Back Pain
(page two of five)

(10) Sciatica could only be produced by stimulation of a swollen, stretched, or compressed nerve root. Back pain was produced in the majority of cases by stimulating the outer layer of annulus fibrosus and the posterior longitudinal ligament.

If the disc is a major source of low back pain then applying specific target therapy for the treatment of disc pathology should improve patient outcomes. VAX-D is a primary, non-surgical treatment for the management of patients with disabling low-back pain and neurological symptoms associated with herniated and degenerative disc disease. Research has shown that the VAX-D table is a decompression device that is capable of reducing intradiscal pressures to negative levels. (11)

Successful reduction of intradiscal pressures with VAX-D represents a technological advance that should provide a means of addressing compressive disc pathology. Creating negative intradiscal pressure is likely to affect both the biomechanical and biochemical causes of discogenic pain. Patients suffering from discogenic pain and/or associated sciatic pain are seeking conservative treatment without the risks associated with injections and surgical procedures.

VAX-D incorporates advanced technology that permits the application of distractive tensions without eliciting reflex muscle guarding. Conventional traction devices have not demonstrated this ability or the ability to reduce intradiscal pressures to negative levels. Studies published in the medical literature report that intradiscal pressure either remains unchanged or increases during traction. (12) It has also been demonstrated that paraspinal muscles are not able to fully relax during conventional traction.

The beneficial effects of VAX-D decompression in the relief of peripheral nerve dysfunction has been previously reported in the literature, (13) and a multi-center outcome study reported that VAX-D treatment was successful in 71% of the 778 cases studied. (14). This study was designed to evaluate the effect of VAX-D on chronic low back pain.

MATERIAL AND METHODS

In association with Quintiles, the world's largest health care consultancy organisation for data analysis in clinical trials, a protocol was developed and then approved by the Human Research Ethics Committee at the University of Wollongong, New South Wales, Australia.

It was predetermined that the treatment would be considered a success if the patient attained a fifty percent (50%) decrease in pain, numerically on the Visual Analogue Scale (VAS). Absolute changes in pain score determined by VAS over time were analysed with repeated measures analysis of variance and t-test. In addition, improvements in disability were recorded on a patient nominated disability rating. Any level of improvement in disability was acceptable. The instruments for determination of these outcomes were supplied by the National Musculoskeletal Initiative of Australia. The study itself was to be conducted in the medical clinics of the VAX-D Spinal Institute and so to prevent bias in the data collection Quintiles were engaged to collect and analyse the data. TENS was selected as an appropriate placebo treatment as a means of establishing a plausible but (probably) ineffective control for an unblinded treatment.

Through advertisement in local papers forty-four patients with chronic low back pain greater than 3 months in duration, with associated leg pain, and a confirmed disc protrusion or herniation on CT Scan or MRI were selected and randomised into the two treatment methods, either VAX-D or TENS. The patients were randomised in sequential order and treatments were determined by a predefined central randomisation list.

The average duration of pain in the patient population was 7.3 years. The conditions for receiving either treatment including travelling to and from the clinic and duration of therapy were designed to be the same for both populations. Inclusion criteria for the study were: age 18-65 years; a minimum VAS score of 2; candidates must live within 45 minutes of the clinic location; capable of thoroughly understanding the information given and following protocol. All candidates signed an informed consent form.

Exclusion criteria were: osseous stenosis; unstable spine (bilateral pars defect or Spondylolisthesis of Grade II or greater); spinal surgical implants; shoulder problems which prevent compliance with VAX-D therapy; spinal pain due to tumor, infection, or inflammatory disease; pregnancy; and previous VAX-D therapy.

Patients randomised to VAX-D were treated according to the manufacturer's protocol. Patients lie on the split table device in a prone position. VAX-D utilises handgrips that the patient grasps with arms extended above the head to stabilise (restrain) the shoulder girdle and upper body. This is thought to be the most effective means of assuring that tensions applied to the pelvis are transmitted accurately along the linear axis of the spinal column during the procedure.

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