An Overview of Vertebral Axial Decompression
Canadian Journal of Clinical Medicine Vol. 5, No. 1, January 1998
Dr. Frank Tilaro, M.D.

INTRODUCTION

Low back pain is a growing epidemic among industrialized societies. In the United States it is the most common work related disorder. The cost to industry is staggering, with estimates running 20 billion dollars or more annually (4,42). Total payments for a single Workman's Compensation claim may be as high as $100,000. Abenhain and Suissa studied the 1-year incidence of work related low back pain in the province of Quebec for the year 1981 (1). Work absence due to back pain has an incidence of 1.4%. Seventy-four percent of work related injuries return to work within 1 month. 7.4% were out of work for more than 6 months. 75% of the direct total cost was borne by 10% of the absentees. Recurrence rates were 20% at 1 year and 36% after 3 years.

Men had higher recurrence rates than women; drivers and nurses had higher recurrence rates than other occupations. The recovery rate of the Quebec workers is similar to other countries. After 1 year 4.3% remained absent from work. Incidence rates of compensated back injuries by industrial sector showed that foresters and miners are at the top with 4.9% and 3.3% respectively.

BACK PAIN - A DIAGNOSTIC AND THERAPEUTIC DILEMMA

Effective diagnosis and therapy requires thorough knowledge of spinal biomechanics. Our approach to back pain has been centered on a patho-anatomical model but unfortunately the model frequently fails to comply with the clinical picture. The Quebec Task Force Report stated: "There is so much variability in making a diagnosis that this initial step (i.e. clinical assessment) routinely introduces inaccuracies which are then further confounded with each succeeding step in care ."(43) Adding to the confusion is the belief by too many physicians, patients and insurers that high tech imaging is the standard for establishing a diagnosis. However, the high rates of false positive and false negative findings point to the inadequacies of these studies in identifying the pain generating lesions (8,19,20,48,49). Nachemson states: "A confirmatory imaging study is indicated only if surgery is contemplated. Clinical symptoms and findings remain the most important basis for diagnosis."(28)

The natural history of low back pain with and without radiculopathy has been described (10,37,47). Spontaneous regression takes place in 80% to 90% of patients with low back pain by 6 weeks and a significant percentage of patients with sciatica report a satisfactory response to conservative medical management. Studies on disc surgery emphasize inappropriate patient selection as the cause for surgical failure (11,16,30,44). In Kramer's address to the International Spine Society he emphasized that the surgical failed back syndrome is the worst possible scenario a spine surgeon faces (22). In North America the incidence for this iatrogenic disease is about 15%, compared to 5% with most European countries (28). Comparisons between the United States and Europe indicate that the frequency of surgery in the U.S. is four times greater (11). Statistics from the Back Pain Outcome Assessment Team compiled from 1979 to 1987 indicate a rapidly growing number of disc excision and fusion operations performed each year, further escalating the cost (11,44).

Studies of the various surgical procedures largely lack validity and controlled prospective studies are rare (7). A randomized study by Revel demonstrated percutaneous discectomy has little value (32) and the same is true for laser discectomy. Chemonucleolysis is superior to saline injection but inferior to surgical discectomy. While chemonucleolysis had its followers for a period of time, it has fallen into disrepute because of the serious side effects including anaphylaxis and myelitis and should no longer be considered an option. There are not any studies demonstrating the superiority of one particular surgical intervention and there is no support for adding a fusion to a routine discectomy (11,27,28).

THE VAX-D THERAPEUTIC TABLE

The VAX-D therapeutic table (Vertebral Axial Decompression) addresses the functional and mechanical aspects of discogenic pain and disease. The table was invented by Dr. Allan Dyer, former Deputy Minister of Health from Ontario and a pioneer in the development of the external cardiac defibrillator. The table is designed to apply distraction tension to the patients lumbar spine without eliciting reflex paravertebral muscle contractions. The patient lies in a prone position, the upper body is over the stationary portion of the table, and the body is restrained by the patient holding on to adjustable handgrips which can be released at anytime for safety.

The table is a split table design, whereby distraction tensions are applied to the patient through a pelvic harness attached to a tensionometer and by separation of the movable part of the table. The distraction-relaxation cycles are automated or variably timed. Distraction tensions and rates are continuously monitored and measured by the tensionometer and the output is shown on a digital gauge and captured on a pen-write printout. The table exerts its effects through decompression of the intervertebral discs.

Dr.'s G. Ramos and W. Martin of the Departments of Neurosurgery and Radiology at the HCA Rio Grande Regional Hospital, McAllen, Texas studied intradiscal pressure during VAX-D therapy.(30)

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