New York City Chiropractic and Wellness Center, Chiropractor in New York City

1. DISTRACTIVE VERTEBRAL AXIAL DECOMPRESSION: PATIENT OUTCOME STUDY	6. Effects of Vertebral Axial Decompression On Intradiscal Pressure.
2. Vertebral Axial Decompression Therapy for Pain Associated With Herniated or Degenerated Discs or Facet Syndrome: An Outcome Study	7. The Science of Decompression
3. A Prospective Randomized Controlled Study of VAX-D and TENS for the Treatment of Chronic Low Back Pain	8. The Treatment of Discogenic Low Back Pain: An Integrated Approach (VAX-D- Vertebral Axial Decompression Therapy)
4. An Overview of Vertebral Axial Decompression	9. Welcome Relief for Low Back Pain
5. Efficacy of VAX-D on chronic low back pain: Study of Dosage Regimen	10. MD News: Non-Surgical Spinal Decompression

New York City Spinal Decompression Specialist DRX 9000 (212) 645-8151

DISTRACTIVE VERTEBRAL AXIAL DECOMPRESSION: PATIENT OUTCOME STUDY
by Vicki Ludwin-Brown, CPHQ, RCP, RRT
8/15/2004

Summary: The outcomes of distractive vertebral axial decompression therapy for patients with low back pain from various causes was reported by Gose, Naguszewski and Naguszewski in “Vertebral axial decompression therapy for pain associated with herniated or degenerated disc or facet syndrome: An Outcome Study” – Neurological Research, Vol. 20, No. 3, April 1998.

“Data was collected from twenty-two medical centers for patients who received VAX-D therapy for low 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; a total of 778 cases. 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 72% of the 778 cases, when success was defined as a reduction in pain to 0 or 1, on a 0-5 scale. Improvements in mobility and activities of daily living correlated strongly with pain reduction.”

In an effort to determine the outcomes of our own patients in this community, we studied our first 51 back patients at ReNew Rehab and Back ‘N Balance. Our outcomes were similar to those reported in the aforementioned article. Additionally, our outcomes were similar with the first 33 patients as compared to the larger sample size of 49 patients. As part of the program evaluation process, The UR committee discussed the program strengths and weaknesses (lack of community and physician knowledge of our application).

Improvement Great improvement	# 25	% 51.0%
Good improvement	10	20.5%
Some improvement	10	20.5%
No improvement	4	8.0%
Total	49	100.0%

Satisfaction	#	%
Very Satisfied	29	59.0%
Satisfied	14	29.0%
Not satisfied	6	12.0%
Total	49	100.0%

Background:

The Utilization Review Committee reviewed all chronic low back pain cases for appropriateness and efficacy of services related to the low back pain program, Distractive Vertebral Axial Decompression.

The quality improvement program related to Distractive Vertebral Axial Decompression Therapy that has been implemented at Back `N Balance and formerly at ReNew Rehab includes the following components:

ƒ Equipment Quality Control (VAX-D was used for all patients)

ƒ Quarterly Equipment Calibration per manufacturer’s guidelines

ƒ Treatment waveform documentation per manufacturer’s guidelines

ƒ Operator Quality Control ƒ Certification of operator ƒ Training Program with Preceptor (20 sessions)

ƒ Clinical Assessment ƒ Physician equipment certification ƒ Physician patient assessment per Manufacturer’s Protocol (VAX-D) ƒ Therapy sessions per Protocol ƒ Physician re-assessment per Protocol ƒ Physician assessment mid-term if lack of progress ƒ Case review by Medical Director of all individual cases ƒ Medical Director review of aggregated results

Period Reviewed: December 2002-August 2004

Utilization Review (UR) Committee members: Vicki Brown, C.P.H.Q., Program Coordinator, Certified VAX-D technician Patti Boos, Records Keeper and Office Manager Glenn A. Thomas, M.D. Denise Endly, R.N.

Process: All patient charts (49) were reviewed for the following criteria:

(1) Adherence to Protocol (24 treatments – 5X week X 4 weeks then 1X/week X 4 weeks)

(2) Efficacy based on pain scale and/or Oswestry Disability index start and end of therapy

(3) Evidence of physician review

(4) Patient satisfaction

Data Process:

Data collection ƒ Pain scale, Oswestry, H&P at initial visit (Back `N Balance, formerly ReNew Rehab) ƒ SF-12 at beginning and >1 month post care (vendor/QHR) and follow up calls before
each utilization review committee meeting ƒ Satisfaction Survey at end of therapy (Back `N Balance/formerly ReNew Rehab) ƒ Daily pain and patient comments documented in technician progress reports ƒ Physician evaluations of patient (2-3: @ start, mid-term, completion of therapy)

Data Entry ƒ Access database for individual entries – by Program Coordinator or Office Manager
Case review ƒ Physician and Program Coordinator with physician reassessments
Data aggregation in Excel database – facilitated by Program Coordinator and assistants ƒ Reviewed by UR Committee

Quality monitoring is done concurrently (daily progress notes) and retrospectively in aggregate (by UR committee). Quality control is completed quarterly.

Results:

Of the 51 total patients, 49 had at least 10 sessions. The reasons for (7) patients not completing the usual treatment protocol of 24 treatments included:

Patient improvement or plateau before 24 treatments (2 patients)
Patient lack of compliance with protocol (1)
Patient inability to pay for further treatments (2 patients)
Patient discomfort with treatment – Inability to lay prone for 30 minutes or pain getting off the table (2 patients)

49 charts of all patients receiving 10 or more treatments were reviewed for the following:

(1) Appropriateness of care:

100% of the charts demonstrated that the protocol was followed: ƒ Patient selection was appropriate per protocol ƒ Therapy proceeded per VAX-D Protocol ƒ Each case was reviewed by the physician

(2) Efficacy of care:

Of the 49 patients treated with > 10 treatments of vertebral axial decompression therapy, 39/49 or 80% of the charts reviewed demonstrated that the patient improved to minimal or no pain post therapy (0-1 on a pain scale of 1-5*).

ƒ No improvement (4/49) =8% (no change in pain scale rating)ƒ Some improvement (10/49) = 20.5% (change of 1 increment in pain scale)ƒ Good improvement (10/49) = 20.5% (change of 2 increments in pain scale) ƒ Great improvement (25/49) = 51% (change of 3 increments in pain scale)

*Pain Rating scale (Oswestry): (0=no pain, 1=mild pain, 2=moderate pain, 3=fairly severe pain, 4=very severe pain, 5=worst imaginable)

(3) Patient Satisfaction:

43/49 or 88% patients were satisfied or very satisfied with therapy. ƒ 6/49 or 12% of patients were not satisfied ƒ 14/49 or 29% of patients were satisfied ƒ 29/49 or 59% of patients were very satisfied

(4) Additional findings:

a. Patient history of previous therapy/back surgery prior to vertebral axial decompression therapy ƒ 28/49 patients (57%) had prior Physical Therapy ƒ 30/49 patients (61%) had prior chiropractic care ƒ 28/49 patients (57%) had prior injections for pain ƒ 13/49 patients (27%) had prior back surgery

b. Average # of treatments per patient = 25

c. Patients ranged in ages from 18 to 81 – Average age was 51 years

d. Average # of years history of back pain– 8 years – Range from .3 to 30 year history

e. Diagnoses were as follows:ƒ 48/49 patients (98%) had lumbar bulging, herniated, protruding, or extruded discs

varying in size from 2mm to 15mm (per MRI report) ƒ 36/49 patients (73%) had concomitant degenerative disc disease ƒ 36/49 patients (73%) had multilevel issues or multiple diagnoses ƒ 35/49 patients (71%) complained of sciatica

f. Surgery after course of therapy = 1/49 or 2%

VAX-D® PROTOCOL and Guidelines

Therapeutic Indications for VAX-D

Low back pain, unilateral or bilateral, with or without leg pain associated with discogenic lesions.
Patients with neurologic deficits
Post surgical patients with failed back syndrome without retained hardware

Contraindications and Potential risks for VAX-D Patients

Primary or metastatic neoplasm in the spine
Vertebral fracture (recent)
Cauda equine syndrome
Unstable spondylolisthesis (eg Pars Defects)
Severe osteoporosis – plain films show greater than 45% bone loss or less than 2.5 standard deviations below the mean on a DEXA test
Severe or unstable medical disorder
Significant shoulder injury – rotator cuff tear
Pregnancy
Ankylosing spondylitis
Arthodesis with retained hardware
Abdominal aortic aneurysm
Spinal infections including osteomyelitis and septic discitis
Severe osseous stenosis
Hemangioma that invades the endplate, greater than 1cm in size that may compromise the vertebral integrity or that may represent a risk of bleeding
Pelvic or abdominal cancer

Vertebral Axial Decompression Therapy for Pain Associated With Herniated or Degenerated Discs or Facet Syndrome: An Outcome Study

Earl E. Gose, William K. Naguszewski* and Robert K. Naguszewski*

Department of Bioengineering, University of Iliinois at Chicago, Chicago, IL. USA *Coosa Medical Group, Rome, Georgia, USA

The outcomes of vertebral axial decompression (VAX-D) therapy for patients with low back pain from various causes are reported. 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; a total of 778 cases. The average time between the initial onset of symptoms and the beginning of this therapy was 40 months, and it was four months or more in 83% of the cases. 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. [Neurol Res 1998; 20: 186-190].

Keywords: Low back pain; herniated disc

INTRODUCTION

For most patients, the cause or causes of persistent low back pain remains poorly understood. 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 imprecise1. 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. In addressing the dysfunction of the disc with discectomy or surgical instrumentation, the biomechanical and physiological function of the disc is permanently disrupted.

Mechanical low back pain is usually 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 (2,3). 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.

Pain generation from degenerative disc disease is probably multifactorial. A number of potential mechanisms are specifically addressed by the lumbar vertebral body separation achieved during therapy. With aging, disc desiccation occurs, disc height is lost, and this process is accelerated with activities which produce high physical loading of the lumbar spine (4). Osteophytes develop along the anterolateral and posterior border of the vertebral bodies, and facet arthropathy increases as degenerative disc change advances (5). Normal vertebral body separation is lost as the disc degenerates. Redundancy of the posterior longitudinal ligament and ligamentum flavum combine with osteophyte encroachment upon the neuroforamen or central canal, resulting in stenosis at these sites, which is increased by axial loading of the spine.

Figure 1: Patient undergoing treatment on the VAX-D Therapy Table

The blood supply to the nerve roots of the cauda equina is sensitive to compression. Even at pressures of only 5-10 mm Hg, the flow in over 20% of the venules was completely stopped (6). Flow in all the capillaries stopped at pressures between 20 and 50 mm Hg. A pressure of 30 mm Hg is slightly less than one pound per square inch, so solute transport is easily reduced. Even vertebral distractions (increased separation) 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. Furthermore, the effects of lumbar spine lengthening may be sustained for a period of time after lumbar distraction has been stopped.

Twomey (7) placed lumbar vertebral columns removed from 23 male cadavers under 9 Kg of sustained traction for 30 min and measured an average increase in length of 9 mm. Thirty minutes after traction was removed, 13 of the 23 specimens had returned to baseline length, but the remaining 10 spines showed residual elongations ranging from 0.3 mm to 4 mm. Additionally, the data suggested that sustained traction had had a longer lasting effect on elderly spines. The mechanism of this residual deformation was not elaborated upon by the author, but disc rehydration may have been a factor since each column was soaked in normal saline and remained saturated by periodic additions of saline to a close fitting bag surrounding each column during the study.

That lumbar traction, if adequately applied, can effect physical change in patients suffering from back pain is well described by Gupta and Ramarao (8). They used water soluble contrast medium and epidurography to study 14 patients with prolapsed intervertebral disc syndrome before and after 10 to 15 days of continuous traction. Ten patients showed definite clinical improvement, with reduction in back pain and sciatica. Nine of these patients showed complete resolution of the defect on epidurogram and one of them showed partial reduction. The authors concluded that disc protrusion may be safely treated by traction. Mathews also demonstrated the effectiveness of lumbar traction in two patients by epidurography. Disc protrusions were decreased and an average vertebral distraction of 2 mm per disc space was shown in radiography (9). Judovich found that a traction force of approximately 26% of the body weight was needed just to overcome the resistance between the lower half of the patient and a (nonsplit) table (10).

Intuitively, lumbar traction should be successful in alleviating many of the conditions which cause low back pain and associated radiculopathy. Unfortunately, studies of clinical efficacy have yielded equivocal results. Previously, the successful application of lumbar traction has been limited by patient tolerance and the design of mechanical devices. Patients had difficulty tolerating the forces needed to relieve pain if delivered continuously. Furthermore, the thoracic corsets worn by patients to prevent movement on the table were uncomfortable, restrictred respiration, and can compromise venous return to the heart. Technological advances have now led to the development of equipment that has been found to achieve decompression of lumbar discs without stimulating the reactive reflexes of the lumbar musculature that can otherwise overcome efforts to effectively distract vertebral bodies.

The VAX-D therapy table is shown in Figure 1. The split table design eliminates frictional resistance between the patient and the table and allows controllable effective axial distraction tensions to be applied to the lumbar vertebral column. The equipment applies distractive forces in a gradual, progressive fashion, designed to achieve distraction of the vertebral bodies without eliciting reactive reflex muscular resistance. A portion of a typical chart recording of the tensile force applied to a patient's spine as a function of time is shown in Figure 2. Each decompression phase, during which the tension is increased, normally lasts for one minute. The force is increased more slowly in the latter part of the decompression phase. The tension is then gradually decreased, over a period of 30 sec, to about 20 pounds, which is maintained during the rest phase. Another cycle then starts. The avoidance of paravertebral muscle contraction, stimulated by homeostatic proprioceptor and axon reflex mechanisms allows the distraction of the vertebral bodies necessary to achieve decompression of the intervertebral disc. The therapy is administered via an automated logic control mechanism which systematically applies distractive tensions and rest periods in a cyclic fashion. The typical therapy session consists of 15 cycles of tension and relaxation. This periodic process allows patients to withstand stronger forces than can be tolerated when static techniques are used and it promotes accommodation and relaxation during the therapy session. The upper body is fixed by means of the patient grasping adjustable hand grips, designed to eliminate the use of a thoracic corset. Consequently, there is no risk of circulatory or respiratory compromise. The pelvis is secured with a specially designed harness that adjusts snugly and applies forces primarily to the lateral pelvic alae, thus minimizing anterior-posterior pressures and reactive muscle spasm during the distractive period of each cycle.

VAX-D treatment has been shown (11) to decompress the nucleus pulposus to pressures below - 100 mm Hg. This creates a tremendous potential diffusion gradient across the disc space, which is otherwise an avascular structure. Glucose and oxygen enter the disc at the end plate region while sulphate ions needed for the production of new glycosaminoglycans enter from the annulus fibrosis (12). Thus therapy may augment nutrient flow into the disc, facilitating structural restoration of the disc and promoting disc rehydration, since proteoglycans bind water (13). These effects may be cumulative with repetitive therapy sessions.

Figure 2: chart recording of tension versus time for five cycles of the typical 15-cycle VAX-D Therapy session

MATERIALS AND METHODS

Data was collected from twenty two medical centers in the USA for patients who received VAXD therapy for low back pain. Only patients who received at least 10 treatments and had a diagnosis of herniated disc, degenerated disc, or facet syndrome, which was confirmed by imaging studies, were included in the study. The average number of treatments was 17 for facet syndrome, 19 for degenerative disc disease, and 20 for other diagnoses. The data contained the patients' assessment of their own pain, mobility, and ability to walk and sit. The pain scale ran from no pain (0) to severe pain (3). The mobility limitation scale was: No limitation (0), slightly limited (1), very limited (2), and completely immobile (3). The activity limitation scale was: walks frequently (0), walks occasionally (1), chairfast (2), and bedfast (3(). The treatment schedule, including the use of other modalities, the duration and frequency of VAX-D therapy, and medication was also recorded, as well as the patient's history. The symptoms were recorded at the beginning, mid-point, and end of the treatment schedule. The patients' satisfaction with the treatment was quantified as: not satisfied (0), slightly satisfied (1), very satisfied (2), and completely satisfied (3).

The data were divided into five groups:

The first group which contained 34 cases, included all patients with extruded herniated discs, whether or not additional lesser problems were present.

The second group contained 195 cases of multiple herniated discs, without extrusion, with or without degenerative disc disease.

The third group consisted of 382 patients with a single herniated disc, regardless of degenerative disease.

The fourth group contained 147 cases of degenerative disc disease, without herniation.

The fifth group contained 19 cases with facet syndrome. Five cases of facet syndrome which had a pain reduction to 0 or 1 before 10 treatments, and one that had a reduction to 2, received less than 10 total reatments, so they were not included in the data base.

RESULTS

If treatment success is defined as a reduction in pain to 0 or 1 on a 0 to 5 scale, the treatment was successful in 71% of the 778 cases. The success rate varied from 53% for the patients with extruded herniated discs, to 73% for patients with a single herniated disc. It was 72% for people with multiple herniated discs and 68% for facet syndrome. On a pain scale of 0 to 5, the people with extruded herniated discs had an average pain of 4.16 at the beginning of treatment and an average of 1.82 after treatment, a reduction of 56%. The cases of multiple herniated discs went from 4.13 to 1.18, a reduction of 71%. The patients with a single herniation had a reduction from 4.16 to 1.09, or 71%. The degenerative fisc cases reduced from 3.93 to 1.17, a 70% reduction. The patients with facet syndrome had a reduction of 4.00 to 1.13, a 72% reduction in pain. Overall, 71% of the patients experienced a reduction in pain to 0 or 1. The reduction in the average pain score was also 71%. One percent of the patients reported increased pain, 7% had no change, 92% improved by 1 unit or more, 87% improved by 2 units or more, and 70% improved by 3 units or more. A summary of these findings is shown in Table 1.

Table 2 shows how the average pain, mobility, and activity scores for the entire group of 778 patients improved during treatment. Although 51% of the pain reduction occurred during the first half of the course of treatment, 56% of the mobility improvement and 55% of the activity improvement occurred during the last half.

On a rating scale of 0 to 3, increases in spine mobility of one grade or more was seen in 77% of the patients with mobility limitations. Functional increases of 1 or more grades in the activity score was recorded in 78% of the patients who, before treatment were either unable to walk or capable of only limited walking. The coefficient of linear correlation14 between mobility and pain scores was 0.72. Between pain and activity the correlation was 0.60, and between activity and mobility it was 0.59. On a scale of 0 to 3, the average satisfaction with treatment was 2.4, which lies between 'very satisfied' and 'completely satisfied'.

In this study, 31 patients had previous lumbar disc surgery. MRI scans showed scar tissue that could potentially entrap nerve roots. Despite this, 84% of this group's pain scores and 71% of their mobility scores and 61% of their activity scores improved by one unit or more with therapy, and 65% of their pain scores were reduced to 0 or 1. Vertebral axial decompression was well tolerated. Vertebral axial decompression therapy outcomes: Earl

E. Gose et al.

Table 2: Variation of average pain, mobility, and activity scores during treatment, and final outcome measures for the entire group

Pain (0-5 scale) Mobility limitation (0-3 scale) Activity limitation (0-3 scale)

Before therapy 4.10 1.81 1.24

At midpoint 2.62 1.30 0.80

After therapy 1.21 0.64 0.27

Overall improvement 71% 65% 78%

Improved by 1 unit or more 92% 77% 63%

DISCUSSION

We consider VAX-D therapy to be a primary treatment modality for low back pain associated with lumbar disc herniation at single or multiple levels, degenerative disc disease, facet arthropathy, and decreased spine mobility. Physiology (pain and mobility) and pathology correlate imprecisely. We believe that post-surgical patients with persistent pain or "Failed Back Syndrome' should not be considered candidates for further surgery until a reasonable trial of vertebral axial decompression has been tried.

Low back mobility increased subsequent to therapy and correlated well with pain reduction. Both of these factors are important in areas such as Workers Compensation and personal injury. Estimates of permanent partial impairment rely heavily on mobility aspects, as seen in the AMA Guides to the Evaluation of Permanent Impairment, 4th edition. Although allowance for pain is made in the percentage of impairment, the determination of impairment is made by determination of spine mobility using the range of motion model. By definition no patient can be assigned any impairment rating until maximum medical improvement (MMI) is reached. We submit that patients can usually be brought to a higher level of MMI by this therapy because of the anticipated improvements in mobility.

In summary, the pain, activity, and mobility scores were all greatly improved after therapy. VAX-D by its unique design may more precisely address the physiology of persistent low back pain than other conventional therapies. We consider it to be a front line treatment for degenerative spondylosis, facet syndrome, disc disease and nonsurgical lumbar radiculopathy.

REFERENCES

Heldeman S. North America Spine Society: Failure of the pathology model to predict low back pain. Spine 1990; 15:718-724.

Wheeler A.D. Diagnosis and management of low back pain and sciatica. Am Family Physician 1995; 52:1333-1341.

Scientific approach to the assessment and management of activit-related spinal disorders. A monograph for clinicians. Report of the Quebec Task Force on spinal disorders. Spine 1987; 12(Suppl 7):1-59.

Videman T, Saina S, Crites Battle M, Koskinen S, Gill K, Paanaman H. The long term effects of physical loading and exercise lifestyles on back-related symptoms, disability, and spinal pathology among men. Spine 1995; 20:699-709.

Anderson GBJ, McNeill TW. Lumbar Spine Syndromes Evaluation and Treatment. New York: Springer-Veriag Wien, 1989: pp.1-215.

Olmarker K, Rydeuik B, Holm S, et al. Effects of experimental graded compression on blood-flow in spinal nerve roots. J Orthop Res 1989; 7:817-823.

Twomey LT. Sustained lumbar traction: An experimental study of long spine segments. Spine 1985; 10:146-149.

Gupta RC, Romarao SV. Epidurography in reduction of lumbar disc prolapse by traction. Arch Phys MedRehabilitation 1978; 59:322-327.

Mathews JA. Dynamic discography: A study of lumbar traction. Ann Phys Med 1968; IV:275-279.

Judovich BC. Lumbar traction therapy-elimination of physical factors that prevent lumbar stretch. JAMA 1955; 159:549-550.

Ramos G, Martin W. Effects of vertebral axial decompression on intradiscal pressure. J Neurosurg 1994; 81:350-353.

Nachemson AL. The lumbar spine: An orthopaedic challenge. Spine 1975; 1:59-71.

Ballard WT, Weinstein JN. Biochemistry of the intervertebral disc. In: Kirkaldy-Willis WH, Burton CV, eds. Managing Low Back Pain, New York: Churchill Livingston, 1992: pp.39-48.

Gose EE, Johnsonbaugh R, Jost S. Pattern Recognition and Image Analysis, Upper Saddle River, NJ: Prentice-Hall PTR, 1996: pp.1-484.
A Prospective Randomized Controlled Study of VAX-D and TENS for the Treatment of Chronic Low Back Pain

Eugene Sherry* MD, FRACS Department of Orthopaedics, Sydney University Peter Kitchener** M.B. B.S. FRANZCR; Russell Smart*** M.B.Ch.B. (Otago) Journal of Neurological Research Vol 23, No 7, October 2001 *Senior Lecturer in Orthopedics, Sydney University, ** Consultant Radiologist, ***Medical Director, VAX-D Australasia PTY Ltd. NSW, Australia

ABSTRACT

Low back pain is one of the most significant medical and socioeconomic problems in modern society. International guidelines call for evidence-based management for the pain and disability associated with musculoskeletal disorders. The purpose of this randomised controlled trial is to address the question of efficacy and appropriateness of VAX-D (Vertebral Axial Decompression) Therapy, a new technology that has been shown in clinical research to create negative intradiscal pressures, and has been shown to be effective in treating patients presenting with chronic low back pain (>3 months duration) with associated leg pain. Successful outcome was defined as a 50% reduction in pain utilising a 10cm Visual Analogue Pain Scale and an improvement in the level of functioning as measured by patient-nominated disability ratings. Patients were randomly assigned to VAX-D or to TENS which was used as a control treatment or placebo. The TENS treatment demonstrated a success rate of 0% while VAX-D demonstrated a success rate of 68.4% (P<0.001). A statistically significant reduction in pain and improvement in functional outcome was obtained in patients with chronic low back pain treated with VAX-D. (Neurol Res 2001; 23:780-784)

INTRODUCTION

Low back pain is a major cause of disability in today’s society. According to the National Health and Medical Research Council (NHMRC), each year approximately 600,000 Australians present with low back pain as a recent illness. Although a high percentage of patients with acute low back pain recover within 4-6 weeks, a significant number of patients suffer from recurrences. Von Korff has studied the natural history and found that approximately 60% will have recurrences. (1) In a study of back pain in primary care, Von Korff and Saunders found that 60% to 75% improve in the first month, 33% report intermittent or persistent pain at year one, and 20% of patients describe substantial limitations at this time. (2) Klenerman et al demonstrated that 7.3% of individuals with acute low back pain who had not recovered by two months still reported high levels of pain and disability at twelve months after onset. (3) Chronic low back pain is increasing faster than any other disability, and 5-7% of the population will report their back problems as being a chronic illness. Fifty percent of work loss caused by back pain is accounted for by duration of disability for longer than 4 weeks. In Australia chronic low back pain affects more than 1,900,000 individuals and costs Australia more than 10 billion dollars each year.

International guidelines call for evidence-based management for the pain and disability associated with musculoskeletal disorders. Today's primary care practitioners have a comprehensive responsibility in the management of their patient’s low back conditions, and they must be aware that recurrences after the presenting episode are likely. The literature suggests that for those who have not recovered by two months, management efforts should begin. (4)

Acute disc injury and discogenic pain is one of the primary processes leading to low back pain and lumbar radiculopathy, although the pathophysiologic mechanisms are still not well understood. It is believed that increases in disc pressures resulting from heavy lifting, vibrational and postural forces etc. are important factors in the pathogenesis of low back pain. The effects of disc hydraulics in herniations or protrusions may cause a mechanical deformation of the nerve roots and a compression-induced impairment of the vasculature. In addition, it has been found that the biochemical properties of the nucleus pulposus may induce a toxic or inflammatory reaction in the nerve root.

There have been many studies indicating that the disc and its associated pathology are identified as a primary cause of low back pain and lumbar radiculopathy. Hirsch stimulated various lumbar tissues in awake patients with the use of carefully placed needles. (5) Stimulation of the posterior portion of the annulus produced low back pain in many individuals. Furthermore, he was able to eliminate the pain by the injection of a minute volume of local anaesthetic into the annulus. Smythe and Wright placed nylon threads into various lumbar tissues while performing lumbar spinal operations. (6) During the postoperative period, they pulled on the threads and asked the patients to describe the location of any pain produced. The annulus fibrosus was the most common site of low back pain, and the compressed nerve root was responsible for sciatic pain. Tension placed on a normal nerve root resulted in no pain.

Falconer and associates published their observations made during exploration of the lumbar spine under local anaesthesia. (7) Murphy reported similar results in his small series of surgical cases. (8) Both authors concluded that the annulus and nerve root were the pain generating tissues. Wiberg in 1950, operating on 200 patients using local anaesthesia of the skin and muscles only, reported that pain emanated from the disc. (9) Kublisch operated on 193 patients using local anaesthesia and drew certain conclusions about the likely origin of back and leg pain. (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 VAXD therapy; spinal pain due to tumor, infection, or inflammatory disease; pregnancy; and previous VAXD 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. The fact that the patient may release at any time during the treatment provides an important safety factor. A special harness designed to apply forces primarily to the lateral pelvic alae is fitted and tightened around the patient. The pelvic harness is connected to a tensionometer at the caudal end of the table. The function of the tensionometer is to provide constant feedback to the programmed logic control and operating system. During the VAX-D session a continuous chart recording is generated plotting the controlled time/energy progress of the entire procedure.

Tensions are applied to the lumbar spine in a cyclic fashion from the baseline tension up to the therapeutic range of fifty to ninety-five pounds. Each treatment session is thirty minutes in length and is comprised of fifteen cycles of decompression alternating with relaxation. Each decompression and relaxation phase may be individually varied as suitable for the particular treatment parameters.

A chart recorder prints the time energy curve for each decompression-relaxation cycle. This affords the technician a means of monitoring and adjusting the decompression process. Patients received VAX-D therapy five times per week for four weeks and then once per week for four weeks in accordance with protocol. All VAX-D treatments were administered by certified VAX-D technicians at four clinics in the Sydney area.

Patients randomised to TENS therapy received treatment at one of the four clinics. Electrodes were placed according to the manufacturer's protocol. Patients lay prone on a treatment table and received TENS for thirty minutes daily for twenty days then once a week for four weeks. All patients receiving TENS were monitored by a technician.

Neither group received any physical therapy modalities, epidural steroid injections or other treatments during the trial. Both patient groups were allowed to take non-narcotic pain relievers and antiinflammatory medication if necessary.

A 10-cm Visual Analogue Scale (VAS) for pain and a four-point disability rating scale were used to assess patient response. The level of pain on the VAS was recorded on a 10cm line marked at one end ‘No Pain’ and marked at the other end ‘The Worst Pain Imaginable’. The written instruction to the patient was to ‘please place a mark on the line below to indicate your current level of pain’. The self-nominated disability rating scale required patients to list the four activities that were most affected by their low back pain. These were scored according to the following criteria: 1 = cannot do at all; 2 = can do but severely limited; 3 = can do but slightly limited, 4 = can do without limitation.

Data was collected at the initiation of the study prior to randomization and at the end of the eight week treatment period in a separate interview. Success was defined as (equal to or greater than) a 50% improvement in the patient's pain and any improvement in their disability rating.

Patients were free to withdraw from the study on their own volition at anytime. The study treatment could be terminated prematurely if any of the following events occurred: patient wished to terminate his/her participation for whatever cause (two cases); the investigator judged it was in the best interest of the patient to withdraw (zero cases); the patient was unable to comply with protocol (zero cases).

The efficacy-evaluable population used for statistical analysis of efficacy is comprised of all patients who were randomised to study treatment, received at least 10 study treatments, had efficacy data recorded after Baseline, and satisfied the inclusion/exclusion criteria.

The primary efficacy measure in this study was the proportion of successfully treated patients in each of the treatment groups. The difference in proportions of successfully treated patients in each treatment group was tabulated and compared using Fisher's Exact Test and 95% confidence limits.

Successfully treated patients were to be followed up at six months to determine whether the successful outcome was sustained.

RESULTS

Forty-four patients were enrolled into the study. Twenty-two were randomised to each of the treatment groups. A summary of demographic characteristics for the 44 enrolled patients is presented in Table 1. Table 1: Demographic data

Characteristic Statistic All VAX-D TENS Two patients (4.5% of 44), Patient 029 and Patient 003, were regarded as having withdrawn/not completed the study according to the protocol. Patient 029, randomised to TENS, withdrew due to not wishing to continue and Patient 003, randomised to VAX-D, withdrew due to treatment no longer being required. No patients were withdrawn by the investigator. Patients 018 and 034 both randomised to VAX-D, did not comply with the study criteria and are therefore excluded from the efficacy-evaluable population. They both had a baseline VAS score less than 2 but this error of inclusion was not picked up until the completion of the trial. The efficacy-evaluable population therefore comprised of 40 patients: 19 patients randomised to VAX-D, 21 randomised to TENS.

No of Patients n 44 22 22

Age (years) Mean 42 41 43

Range 22 - 57 27 - 57 27 - 55

Sex Female n 21 11 10

Male n 23 11 12

Race White n 40 20 20

Asian n 4 2 2

Chronicity Mean 7.3 8.4 6.2

Yrs of Pain Range 0.25 - 30 0.25 - 30 0.25 - 28

A summary of the data collected at baseline and post-treatment in the efficacy-evaluable population is presented in Table 2.

Table 2: Efficacy-evaluable population

Characteristic Statistic VAX-D TENS

No of Patients n 19 21

Number of treatments Mean 24.1 18.0

Range 18 - 36 10 - 24

Baseline pain (VAS) Mean 5.99 5.44

Range 2.1 - 8.7 2.7 - 8.5

Post treatment pain (VAS) Mean 1.85 5.97

Range 0 - 5.6 1.8 - 8.5

Decrease in pain (%) Mean 69.1 -17.1

Range 11.1 - 100 -123 - 33.3

Disability Pre-treatment Mean 2.2 2.2

Rating Range 1.5 - 3 1.75 - 3.0

Post treatment Mean 2.9 2.2

Range 2.0 - 4.0 1.5 - 3.0

Improvement in disability rating Mean 33.8 -2.23

(%) Range 0 - 100 -36.4 - 50.0

Successful cases n 13 0

Percent 68.4% 0%

In the efficacy-evaluable population the proportion of successfully treated patients was 13 out of 19 patients (68.4%) for the VAX-D treatment group compared to zero out of 21 (0%) for the TENS treatment group. There was a high statistically significant treatment group comparison p-value of <0.001. The 95% confidence interval for the difference in proportions of successfully treated patients, comparing VAX-D with TENS was 47.5% to 89.3%.

In the VAX-D group all patients recorded some improvement in their pain levels whereas in the TENS group 13/ 21 recorded an increase in pain.

At six-month follow-up, of the 13 successful cases, 2 have been lost to follow-up, 1 case suffered a significant other injury and of the remaining 10, seven have shown sustained success (ie. they still meet the criteria for successful outcome).

The results reported for the TENS group were less that that expected for a placebo control. The negative outcomes may have been due to the fact that the TENS patients (and the VAX-D patients) had to travel to and attend a medical clinic five days per week for four weeks, and one day per week for four weeks. This fact that both treatment groups had to travel to, and attend the clinic, was necessary to ensure that the only variable between the two groups was in the type of treatment that they received. The benefits of treatment in the VAX-D group clearly outweighed the negative effects of travelling, which became evident in the placebo group.

DISCUSSION

Disc stresses coupled with ongoing increased intradiscal pressures from mechanical loading may lead to failures in the normal biomechanics of the disc and progress to degeneration, posterior displacement of the nuclear material, annular disruptions and herniations. Other causative factors in the course of disc degeneration are negative diffusion gradients, reduction of the fluid content of the nucleus pulposus, and abnormal disc metabolism. With positive disc pressures throughout the day that are above diastolic pressure, the metabolism of the disc becomes anaerobic thus impeding the normal reparative healing abilities.

Proteolytic enzymes (matrix metalloproteinases) reside in the disc and have been implicated in disc degeneration. (15) The matrix metalloproteinases are regulated by specific inhibitors (TIMPS), cytokines (Interleukin-1) and growth factors. (16) Spinal loading may interfere with diffusion into the disc by reducing the gradient across the vertebral endplate. As disc metabolism becomes anaerobic, there is an accumulation of lactic acid, fall in pH, loss of chondrocyte and fibroblast function, and activation of the metalloproteinases.

Although the mechanism of action may not be fully understood the thixotrophic (17) properties of the nucleus material may facilitate nuclear migration toward the centre of the disc under negative pressures created by VAX-D.

It has been shown experimentally that elevated lactate levels and low pH in the disc prohibit disc proteoglycan synthesis and accelerates matrix degeneration (18).

Destruction of the proteoglycan matrix and fluid retention properties can lead to a degenerative cascade with loss of cellular reparative functions and vitality. The reduction of intradiscal pressures may enhance the diffusion gradient across the endplate into the avascular disc. It has been postulated that mechanisms that facilitate oxygen and nutrient uptake in the disc may exert a beneficial effect on the metabolism and restorative functions.

Successful reduction of intradiscal pressures with VAX-D therapy represents a technological advance in lumbar spinal treatment and is likely to affect both the biomechanical and biochemical causes of discogenic pain. The results from this study demonstrate that VAX-D is an effective treatment for the management of patients with chronic low back pain and is significantly superior when compared to TENS therapy. Analysis of the data demonstrated an attributable success rate of 68.4% for VAX-D. These findings are consistent with earlier studies by Gose E, Naguszewski W, Naguszewski R. (14)

The results of this prospective study demonstrated that VAX-D can achieve a statistically significant improvement in pain and functional outcome in managing patients suffering from disc related chronic low back pain.

ACKNOWLEDGMENTS

Australian National Musculoskeletal Initiative: For advice and instruction on the use of instruments for the outcome measures used in the present study.

Jane Ambrose, Biostatistician Quintiles: For statistical analysis of the data. DISCLOSURE Dr Russell Smart is contracted to and a shareholder in VAX-D Australasia Pty Ltd, a private company

that delivers VAX-D service in Australia.

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Kublisch S, Ulstrom C, Michael C. The Tissue of Low Back Pain and Sciatica: A Report of Pain Response to Tissue Stimulation During Operations on the Lumbar Spine Using Local Anesthesia. Orth Clinics of North Am 1991; 22:181-187
Ramos G, and Martin W. Effects of vertebral axial decompression on intradiscal pressure. J. Neurosurg 1994; 81: 350-353.
Anderson G, Schultz A, Nachemson A. L. Intervertebral Disc Pressures During Traction. Scand J Rehabil Supp 1983; 9:88-91
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18. Matsui Y, Macda M, Nakagami W, Iwata H. The Involvement of Matrrix Metalloproteinases and Inflammation in Lumbar Disc Herniation. Spine 1998; 23:863-69

An Overview of Vertebral Axial Decompression

Dr. Frank Tilaro, M.D Canadian Journal of Clinical Medicine Vol 5, No 1, January 1998

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) The patient population was comprised of individuals with unresolved low back pain who were referred for neurosurgical consultation. Previous management programs included conventional bedrest, medications, physical therapy, and or chiropractic treatments. Depending on the diagnosis and findings of the examinations, patients were assigned to one of the following study groups: Intradiscal Pressure Study and Clinical Outcome Assessment Study. Patients with a subligamentous herniation at L4-5 who were candidates for percutaneous discectomy were included in a study of intradiscal pressure manometry. The pressure measurements were recorded by two different methods; an Ohmeda pressure transducer connected to a Hewlett Packard pressure monitor via a saline bridge and a Camino fiberoptic intracranial transducer adapted for intradiscal measurements. Both transducers were recalibrated after each procedure utilizing a Pneumatic Calibration.

ANALYZER

The transducers were placed in the L4-5 disc under A-P and lateral fluoroscopy. With the catheter in place the patient was placed prone on the VAX-D table. Various decompression tensions from 50 to 100 pounds were applied. The distraction tensions and the resulting changes in intradiscal pressure were observed on digital readout and recorded on a graph tracing produced by the chart recorder. Intradiscal pressures were significantly reduced to minus 150-160mmHg. It was observed that a threshold distraction tension was necessary to develop negative pressures in the disc. The extent of decompression measured in mmHg follows an inverse relationship to the tensions applied.

The significance of this study cannot be overemphasized. The reduction of intradiscal pressure to negative levels has far reaching therapeutic implications. Prior to the introduction of VAX-D, a non surgical method for disc decompression was unavailable. In numerous studies, conventional traction has never demonstrated a reduction of intradiscal pressure to negative ranges, on the contrary many traction devices actually increased intradiscal pressure most likely secondary to reflex muscle spasm .(5)

INDICATIONS AND GENERAL USE OF THE VAX-D THERAPY TABLE

VAX-D is indicated for patients with low back pain that has been unresponsive to conventional therapy for 6-8 weeks. Patients with radiculopathies are also candidates. The presence of a neurological deficit does not affect patient eligibility since studies have revealed the outcome in patients with neurological deficits was not affected by surgical or medical management.(15) The presence of a rapidly progressive neurological deficit is an indication for surgery. Patients presenting with a fusion and the post surgical failed back syndrome may also be candidates.

Contraindications for VAX-D therapy include infection, neoplasm, osteoporosis, bilateral pars defect or Grade 2 spondylolysthesis if unstable, fractures, the presence of surgical hardware in the spine, and the cauda equina syndrome. Patients with lateral stenosis and central stenosis may respond if severe secondary changes are not present in the vertebra. The patient should be evaluated by a therapist or physician prior to initiating therapy and routine spine films are necessary to rule out any contraindications. A CT scan or MRI is not necessarily a prerequisite before therapy. The daily therapy sessions are administered by a trained VAX-D technician. All VAX-D technicians are encouraged to complete a certification exam. Treatments are administered on a daily basis for approximately twenty sessions and are routinely given Monday through Friday. An occasional patient may require a short maintenance period where 2 to 3 treatments a week are given for 2 to 4 weeks post therapy. The average patient has required 20-25 sessions. Each session is comprised of 15 cycles, each cycle being 1 minute in distraction and 1 minute in relaxation.

The table is designed to be operator friendly. With the patient standing, a specially made pelvic harness is fitted and tightened on the patient. The patient lies prone on the table with the lower portion of the belt placed at the level of the table separation point. The adjustable handgrips are positioned such that the elbows remain straight. Repositioning and tightening of the pelvic harness is completed at this point. The harness is attached to a movable pretension housing that maintains a baseline tension of 20 lbs. throughout the rest phase. Once the pretension is set the treatment cycles may begin. The Ramos study indicated that 50 lbs. of tension was the threshold tension necessary to develop negative intradiscal pressures. The p.s.i. is slowly increased until tensions of 60-80 lbs. are developed, this may take 3 to 4 days of therapy. Some patients have required 90-100 lbs. of tension for a full therapeutic effect.

Pain distribution frequently changes during or immediately after therapy. A phenomenon called centralization first observed by McKenzie (24) has been noticed during a course of VAX-D therapy. Centralization is the process by which the pain pattern migrates from a peripheral distribution to a more central or proximal location and is an indication of a favorable clinical outcome. Centralization of pain patterns may be associated with increased central back pain, but this should be interpreted as a positive sign and is likely secondary to stretching of the posterior longitudinal ligament as the lateral distortion of the disc retracts to a more concentric position. Centralization is a predictable prognostic indicator for symptomatic discs and annular competence (12) The observed occurrence of centralization during VAXD therapy in a patient who initially could not centralize their pain pattern implies healing of the annulus as a result of VAX-D therapy.

As higher distraction tensions are reached few patients may report an increase in pain of a different quality. Overstretching of the soft tissues in the back likely represents the cause of this pain and the patient should be treated by decreased distraction tensions, so as not to traumatize the soft tissues. The development of a sharp, burning, radiating pain during therapy could represent the stretching of an entrapped nerve. Since the breakdown of scar tissue is an objective, the patient should continue but distraction tensions should be reduced such that any pain elicited does not last more than 15-20 minutes post therapy. Distraction forces are then slowly increased over the ensuing days.

No serious side effects have been reported with VAX-D therapy. A limiting factor affecting the patient's tolerance to therapy is stress to the shoulder girdle and rotator cuff. This may be mitigated by placing a roll under the axilla of the affected side. Should a patient have discomfort from any cause, they may release the handgrips at any time. This adds an important safety factor to the treatment.

MECHANISM OF ACTION

An understanding of spinal biomechanics is necessary to appreciate VAX-D's mechanism of action, to effectively treat and diagnose spinal disorders, and to objectively review old and new therapies. The literature is replete with biomechanical data. Vogel and Stahl have carried out in vitro experiments on intradiscal movements with symmetrical and asymmetrical loading. (21) With symmetrical loading, the nucleus expands and is retained by the annulus. By contrast, if the disc is subjected to an asymmetrical load, the nucleus migrates to the area of least load or resistance.(38) With removal of the load, the nucleus moves from an eccentric to a more concentric position within the disc. Relocation can be accelerated by compression in the opposite direction or by distraction. (21) The annulus of a normal disc can restrain the nuclear movement, but when the elastic properties of the annulus are compromised the structures become susceptible to injury. Fissures and ruptures develop which allow the nucleus to migrate.

Fissures are normally present by 30-35 years of age and increase with advancing age. Fragment sequestra appear as a result of age and trauma. These fragments can move independently and result in protrusions and disc prolapses. Migration of nuclear material and sequestra is influenced by compressive forces, shearing, and increased intradiscal pressure. (24)

Epidemiological data and scientific data have demonstrated that prolonged or repetitive flexion loads stress the posterior annulus resulting in discogenic pain and in some patients disc herniation.(3,25) Adams and Hutton carried out experiments with gradual loading of the disc and concluded that disc prolapses can occur with a sustained flexion load.(2) Hickey and Hukins performed experiments with bending and torsion and demonstrated that the annulus failed posteriorly.(17) Shirtzi-Adl demonstrated that disc fiber layers are most loaded in flexion and least in extension.(40) Nachemson's research on intradiscal pressures showed pressures were highest with flexion.(26) The outer third of the annulus is innervated by the sinuvertebral nerve. Any asymmetrical load associated with elevated intradiscal pressure can result in overstretching and fatigue of the annulus, thereby stimulating the mechanoreceptors in the outer third of the annular wall. Eventually, fissure's will develop in the annulus which can lead to herniation of the central mass of the nucleus. By reducing intradiscal pressure with VAX-D therapy, a therapeutic and prophylactic effect can be realized.

Numerous studies utilizing discography have helped us to understand the role of the disc as a pain generator. Provocational discography is the standard test for discogenic pain.(41) Its reliability has been questioned and opponents generally refer to the work of Holt, but his study has been refuted on methodological grounds.(9,18,41) Recently a pathological marker of symptomatic disc disruption called the high intensity zone (HIZ) was demonstrated on MRI using spin echo gradient heavy T2 imaging.(6,38) An HIZ is evident in the posterolateral view on the sagittal section, which on provocation discography corresponded to a Grade 3 radial tear. The high signal intensity represents fluid within the fissure that may be causing pain either by chemical irritation or mechanical traction of the sinuvertebral nerve. By its cyclic action and ability to reduce intra-negative pressure, VAX-D therapy could displace the fluid to the internal portion of the nucleus thereby ameliorating pain and enhancing healing of the annulus.

Donelson demonstrated it is possible to predict annular competence with the McKenzie mechanical assessment protocol.(12) In his study patients were separated into centralizer's and non centralizer's. Discography was performed in both groups. Centralizer's tended to have an intact annulus or Grade 1-2 tears. Non centralizer's had a disrupted annulus , that is fissures to the outer third of the annular wall or Grade 3 tear. This is very exciting news for those who appreciate the centralization phenomenon because it allows us to clinically assess the competency of the annulus. Patients who centralize on initial evaluation may be treated with specific exercise. Patients who do not centralize on initial examination are excellent candidates for VAX-D therapy. With such an approach, the patients disposition regarding effective therapy is known immediately, which arguably translates to reduced disability and reduced cost.

VAX-D therapy has been shown to convert non centralizer's to centralizer's during or after successful VAX-D therapy. This implies VAX-D is conducive to annular healing. Asymmetrical loading of the disc and increased intradiscal pressure is partly responsible for internal derangement, disc degeneration and herniation. Changes in intradiscal pressure also play a prominent role in affecting nourishment of the disc since the disc is an avascular structure and receives its nourishment primarily by diffusion. Intradiscal pressure that is greater than capillary pressure in the vertebral body impedes oxygen diffusion to the disc which in turn impedes healing.(13) Reducing intradiscal pressure with VAX-D creates a diffusion gradient into the disc allowing nourishment to proceed. Solutes such as oxygen have a steep concentration gradient across the disc, with the peripheral concentration 20-30 times more than the concentration at the center of the nucleus. The availability of oxygen may be inadequate to meet the metabolic requirements required to heal a damaged annulus, and higher concentrations of lactate have been measured within the central portion of the disc. By reducing intradiscal pressure, VAX-D therapy creates a diffusion gradient thereby enhancing solute transfer. High levels of lactate could facilitate chondrocyte cell death as well as increase the activity of degradative enzymes further promoting the loss of the proteoglycan cell matrix. A vicious cycle is produced, accelerating disc degeneration. The mechanical effects of fluid loss during a compressive load are followed by a slow rate of disc deformation termed creep. The rate of creep is faster in a damaged or degenerated disc than a normal disc. Both vibration (overstress) and inactivity (understress) affect the rate of creep and disc degeneration. Pigs who were subjected to vibratory creep had lower levels of oxygen and sulfate transport, and higher levels of lactate within the disc.(13)

Somewhere between the overstress of vibration and the understress resulting from inactivity is an optimum mechanical environment.

Through its action, VAX-D may be capable of restoring that environment, enhancing healing of the disc and retarding degeneration. The pathophysiology of nerve root compression has been described by Rydevik.(33,34,35) The nerve root ganglion has an extensive venous plexus, which if obstructed, results in venous hypertension and endoneural edema, leading to hypoxia, ischemia and pain. External decompression with VAX-D therapy can be expected to relieve venous hypertension and reverse the pathognomonic process.

By significantly reducing intradiscal pressure, VAX-D promotes retraction of the herniation into the disc. VAX-D therapy could possibly shear a herniation from its connection to the central nucleus, creating a severed fragment within the spinal canal. This sequestered disc is susceptible to small vessel invasion and digestion as a result of contact with the epidural space. Reinforcing this theme is the study by Modic et al who studied the natural history of disc herniation by MRI in patients with acute radiculopathy and discovered that large (6mm) sequestered hernias were the first to undergo spontaneous resolution.(23)

I have studied sensory nerve dysfunction measured before and after VAX-D therapy, in order to determine the effect of VAX-D on nerve root compression. The results from this study are very significant and the data will be published in the future. Inflammation very likely plays a role in disc pathology and herniation, but the response to anti-inflammatories is rather disappointing. Saal found high levels of Phospholipase A2 in human disc samples removed at surgery in patients with radiculopathy.(36) As the enzyme responsible for liberation of arachidonic acid from cell membranes, Phospholipase A2 is the rate limiting step in the production of prostaglandins and leukotrienes. Controlled studies have shown that anti-inflammatories are not useful for acute sciatica,(46) but since solute transfer to the disc may be enhanced by VAX-D therapy, the administration of antiinflammatories during VAX-D therapy may result in higher concentrations of the drug within the disc, neutralizing inflammatory mediators responsible for nerve root inflammation and some forms of discogenic pain. As previously mentioned, the fluid within the HIZ is thought to be an inflammatory fluid and VAX-D may be able to effectively pump this fluid into the central nucleus where it is not possible for it to exert an inflammatory effect. The fissure may be able to approximate its borders and heal once the fluid is pumped out.

VAX-D VS. TRACTION

The VAX-D table is an external decompression device and this separates it from conventional traction. Studies verifying decompression of the disc and nerve root are now available for VAX-D. I reviewed the literature and I could not find any available data that conventional traction reduced intradiscal pressure to the negative range nor are there any studies on conventional traction showing beneficial effects in nerve root compression and conditions associated with discogenic dysfunction.

Many patients who receive VAX-D therapy have had chronic back pain and failed numerous modalities including traction. Their positive response to VAX-D therapy, after having failed conventional therapy and traction confirms VAX-D's assertion that it is not conventional traction.

CLINICAL STUDIES

The Acute Low Back Distress Study was conducted by the John P. Robarts Research Institute, London Ontario. The efficacy of VAX-D therapy was established with this study. The parameters measured were severity and duration of pain and disability, including analgesic requirements, and the presence and degree of neurological involve-ment. One hundred and ten patients were entered into the study.

The treatment was considered a success if the baseline aggregate score for pain and disability was reduced by 50% after 10 treatments of VAX-D therapy. Sixty-six percent of the patients achieved success according to the study protocol. Prior to therapy the aggregate score for pain and disability was

5.1 and after 10 treatment sessions in the successful group it was 1.2.

The Clinical Outcome Assessment Study was conducted at McAllen HCA Hospital by Dr. G Ramos.(31) Fifty-two patients completed VAX-D therapy as the primary modality. Thirty-eight patients (73%) achieved a positive outcome with remission of their low back pain symptoms and a return to functional levels of activity. Ninety percent of the recovered group were suffering from disc herniations, the majority (89%) being subligamentous while 11% had extruded herniations. Neurological deficits did not compromise the response to therapy.

Review of the patients clinical findings for those who achieved remission showed that 33% exhibited neurological deficits and 73% had sciatic pain prior to therapy with VAX-D. Dr. E. Gose, Dr. W Naguszewski, and Dr. R Naguszewski have completed an outcome study of VAX-D therapy from over twenty medical centers that included over 700 patients. Patients with back pain, with or without leg pain were included in the study as well as the failed surgical back patient. All patients had a diagnosis of a herniated disc, degenerative disc or facet syndrome. The authors are very enthusiastic about the outcome and have prepared a detailed report of their findings which have been accepted for publication in another respected medical journal.

An outcome study at Columbia Hospital, Tulsa OK. is currently being conducted that shows a level of success consistent with the above study.

SUMMARY

VAX-D therapy addresses the biomechanical aspects of discogenic disease and achieves its objective through decompression. It should be utilized in patients with low back pain, with or without radiculopathy who have failed conventional therapy (physiotherapy and chiropractic), and should be utilized prior to addressing surgery. By addressing the altered biomechanics responsible for disc disease, the VAX-D therapeutic table not only alleviates pain but has been shown to exert a beneficial effect on a major determinant in the equation responsible for discogenic disease, that is elevated intradiscal pressure.

Further analysis of future and unpublished research should be considered to further validate the therapeutic benefit of VAX-D therapy, however, these clinical studies have shown it to be effective in back pain syndromes with or without radiculopathy including herniated discs and internal disc disruption.

The chronic back pain patients and surgical patients are very costly to society. Since many of these patients are responsive to VAX-D therapy, this unique non-obtrusive means of managing the common forms of debilitating low back pain associated with discogenic disease could represent a considerable savings.

ABOUT THE AUTHOR

Dr. Frank Tilaro is a board certified internist who has been practicing orthopaedic medicine for the last 12 years. Dr. Tilaro has restricted his practice to orthopaedic medicine. He is a member of the American Back Society, the McKenzie Institute, the American Association of Orthopaedic Medicine and the British Institute of Musculoskeletal Medicine. Dr. Tilaro is medical director for The Advanced Spinal Institute in Ogden Utah and director of education and clinical research for VAX-D Medical Technologies, Palm Harbor, Florida. Dr. Tilaro resides in Ogden, Utah and can be reached at 1-801-698-0270.

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Efficacy of VAX-D on chronic low back pain: Study of Dosage Regimen

Gustavo Ramos M.D, Department of Neurosurgery and Radiology, Rio Grande Regional Hospital, McAllen Texas

ABSTRACT

Vertebral Axial Decompression (VAX-D) is capable of reducing intradiscal pressure to the negative range . The purpose of this study was to compare the effects of two dosage regimens of VAX-D treatments on the level of low back pain in patients who were referred to a neurosurgical practice after failing standard medical therapy. In this study one group of patients received an average course of treatment consisting of 18 daily sessions and another group received half that number of daily treatment sessions. The treatment parameters for all patients differed only in the number of sessions. Seventy-six percent of the higher dosage group achieved remission of low back pain compared to forty-three percent of the lower dosage group. Chi-square analysis revealed that the differences in response in the two dosage groups were statistically significant at a P < .0001.

INTRODUCTION

Low back pain continues to frustrate the medical profession, patients, employers and the insurance industry. Although many patients have an indolent course with spontaneous resolution, a significant number of patients continue to experience symptoms. Ninety percent of patients with acute low back pain improve within 6 to 12 weeks This formed the basis for the AHCPR guidelines. However, many spinal physicians believe these guidelines to be inadequate (1). In a study of back pain in the primary care setting, Von Korff and Saunders found that 50% to 75% improve in one month, 33% report intermittent or persistent pain at one year, and 20% of patients had substantial limitations at one year (2).

Determining the pain generating tissue has not been an exact science. The diagnosis is considered confirmed when imaging techniques reveal a herniated disc, nerve root compression, and objective signs in the appropriate dermatome. Discography and selective nerve root blocks can provide the diagnosis in patients without sciatica (Quebec 1 and Quebec 2 pain patterns) but are invasive, painful, frequently not covered by insurance companies and not readily available.

Understanding the clinical anatomy of the spine is a prerequisite to understanding pain generation. The outer third of the annulus is innervated by the sinu-vertebral nerve (3,4,5,6,7,8,9,). Kuslich, employing progressive local anesthetic to explore the lumbar spine concluded the outer annulus is the tissue of origin in most cases of low back pain (10). The posterior longitudinal ligament is a highly innervated structure and is intimately connected with the posterior central portion of the annulus and Kuslich found it was frequently tender and produced central low back pain. Although Kuslich was unable to differentiate its specific role, in general, when the posterior annulus was tender the posterior longitudinal ligament was also sensitive. Nachemson believes the intervertebral disc is the likely structure responsible for pain and provides indirect proof (11). Compelling evidence points to the intervertebral disc as the significant pain generator (12).

Conservative medical care revolves around modalities, exercises, stretching, manual manipulative techniques, anti-inflammatory and other medications. The modalities have no intrinsic value and most exercise and stretching programs are generally empiric and may not benefit many patients. This is not to say that exercise in itself is not beneficial. Experimental data with dogs demonstrated that moderate exercise over long periods of time reduced lactate concentration in the outer portion of the annulus and the central nucleus pulposus (13). This may explain why general exercise and fit people have a lower incidence of low back pain (14).

Physical therapy has not been demonstrated to be useful for treating low back pain of discogenic origin(15). Anti-inflammatory drugs are useful in acute muscle strains but are ineffective in sciatica and chronic low back pain. Manipulation may break adhesions or displace an annular fragment from the joint but is ineffective in disc protrusions. Manipulation has not been proven to be of benefit except in the acute phase (16). Pain from the Sl joint can be ameliorated by manipulation and some chronic ligamentous sprains are amenable to prolotherapy (17,18). Myofascial conditions may be treated by trigger point release. Specific medical therapy for the disc is wanting.

Patients who fail therapy at the primary care level (general practitioners, internists, physical therapists, and chiropractors) are routinely referred to the neurosurgeon or orthopedic surgeon, especially if abnormalities are noticed on CT scan or MRI. The majority are not ideal surgical candidates and both the doctor and patient find themselves at an impasse. A rush to surgery in the poorly selected patient can result in the failed back syndrome which Kramer calls the "worse possible scenario the spine surgeon faces"(19). Unfortunately this iatrogenic disease is increasing at alarming rates in North America (20). Failed disc excision can result in a litany of procedures including fusion, surgical instrumentation, removal of hardware, and subsequent problems at levels above and below the previous surgery.

Recently a medical procedure called the VAX-D (Vertebral Axial Decompression) has shown promise in patients with chronic low back pain. A retrospective study performed on 778 patients with low back pain with or without radiculopathy was published. Significant reduction in pain and significant increase in activity was found in over 70% (21). All patients had failed standard medical therapy and the average duration of symptoms for the group was over 3 years ( 43 months). A prospective randomized control trial conducted on patients suffering from chronic low back and leg pain reported that 68% of the group on VAX-D achieved remission . Statistical analysis established that the success rate with VAX-D was significantly higher than the control group. (22). A long term study that followed the progress of cases four years after VAX-D found that more than 50% had remained in remission without further treatments and 91% had been able to resume their normal daily activities. (23) Published data has also demonstrated the effectiveness of VAX-D in reversing sensory nerve dysfunction in patients with compressive radiculopathy (24,25)

VAX-D has a direct effect on the disc through reduction of intradiscal pressure, thereby achieving medical decompression. Ramos and Martin performed intradiscal pressure measurements during treatment with VAX-D and pressures as low as minus 150mmHg. were recorded (26). Intradiscal pressures have been measured with conventional traction devices, both active and passive. A significant reduction in pressure was never observed, in fact active traction doubled intradiscal pressures (27). Biomechanical studies have implicated elevated intradiscal pressures in the equation for annular failure. (28,29,30,31,32)

VAX-D applies distraction tensions to the patients lumbar spine without eliciting reflex paravertebral muscle contractions. This differentiates this procedure from conventional traction (33). A computer programmed logic computer, which accepts feedback during distraction, features in the unique performance. The resultant time- energy curve for VAX-D is logarithmic and has been described mathematically in the patent on the procedure.

The procedure is very safe and patient friendly. The patient lies prone, the upper body is over the stationary portion of the table, and the body is restrained by the patient holding on to adjustable hand grips, which can be released at any time 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 and variably timed. Each distraction and relaxation cycle is captured on a chart printout, providing the operator with a time-energy curve that allows constant monitoring of the patient. Fatigue, decompression, and excessive muscle contraction can be observed from the chart printout. This allows the operator to adjust the therapy. The protocol has been formally amended since initiating this study. Patients receive on average 20 daily sessions, employing tensions from 55 to 85 pounds. Each session is 15 cycles characterized by I minute in distraction and 1 minute in relaxation. Once the patient is asymptomatic or the clinical symptoms have reached a plateau the tension is reduced by for the remaining course of therapy.

Indications for VAX-D are patients with low back pain (Quebec 1,2, or 3) due to disc disease who have not responded appropriately to standard medical therapy. In the Gose study, the best responses were observed in patients with subligamentous hernias (21). Contraindications to therapy are cauda equina syndrome, tumor, infection, severe osteoporosis, fracture, bilateral pars defect, unstable spondylolisthesis and the presence of surgical instrumentation.

Patients with symptomatic osseous lateral stenosis are poor candidates and patients with osseous central canal stenosis are not expected to respond.

The purpose of this study was to evaluate the response to VAX-D therapy in patients with chronic low back pain with or without leg pain who were referred to a neurosurgical clinic after failing standard medical therapy. Patients who were considered appropriate candidates for surgery underwent surgery.

MATERIALS AND METHODS

The patient population for this trial consisted of patients were who referred for neurosurgical evaluation after exhausting standard medical management by family practitioners, internists, orthopedist, physical therapist and chiropractors in the Rio Grande Valley, Texas. Over 150 new patients are seen annually and about 40% undergo surgery. Patients were selected for VAX-D therapy if they had contained discs, non-progressive neurological deficits and no contraindications to VAX-D therapy. Some patients considered surgical candidates refused surgery and opted for VAX-D therapy. Patients with stable neurologic deficits underwent treatment with the VAX-D. All patients had imaging studies (MRI or CT scan) prior to VAXD therapy to confirm the diagnosis of a discogenic disorder that was consistent with the clinical findings.

The average duration of symptoms was 10 months. Most patients were between 30 and 50 years of age, the youngest was 15 years and the oldest 76 years. The average age was 39.5 years. Fifty-five (55) women and eighty-seven (87) men took part in this study.

Patients receiving VAX-D therapy were required to stop all other forms of therapy during their treatment period and for 4 weeks after terminating therapy. This included any modalities, back exercises, or stretching programs. Medications were allowed on a prn basis.

All patients received 15 distraction and relaxation cycles per day on a daily basis administered five days per week. A complete session takes 30 to 45 minutes. Therapy was initiated at 55 to 65 pounds and increased to 70-90 pounds as tolerated. In a previous publication (26) by the author, 40 -50 pounds was the required threshold necessary to achieve negative intradiscal pressure. The treatment procedure administered to all patients was the same except for the number of sessions employed as the prescribed course of therapy. The prescribed course of therapy employed for a period of time was limited to 10 daily sessions (10 Sessions Group). Subsequently the prescribed course of therapy was increased to 20 daily sessions (20 Sessions Group) . Patients that achieved remission prior to completing the prescribed number of treatment sessions were included in the results for the assigned group but were not required to complete the prescribed course of therapy. The average course of therapy in the 10 Sessions Group was 9 daily sessions whereas the 20 Sessions Group received on average 18 daily sessions.

The level of pain on a scale of 10, with 0 as no pain and 10 as the worst possible pain, was recorded on each patient prior to the onset and on completion of the prescribed course of treatment . Each patient also recorded their Activities of Daily Living (ADL) on a scale of 0 to 5 with 0 being no impediment to 5 being confined to bedrest.

RESULTS

One hundred and forty-two patients that were consecutively treated with VAX-D therapy were included in this study. Table 1. shows the distribution of the diagnosis of the cases treated in this series. There were ninety-one (64%) patients in the 10 Sessions Group and fifty-one (36%) patients in the 20 Sessions Group .

Remission was defined as 90% or greater relief of pain, back to work without limitations, and ability to carry out ADL’S. Partial remission was defined as persistence of some pain but ability to carry out most ADL's and return to work with some restriction of duties, depending on the occupation. Negative response was defined as no change in the level of pain and/or ADL.

Table 1: Case Distribution by Diagnosis