METHOD: Pubmed and Medline were searched for all English language peer – reviewed literature using the terms “motorized spinal decompression, VAX-D, DRX9000, DTS therapy.” All literature was covered either directly after 2006 or by literature review studies prior to 2006.

Analysis: 6 out of 7 high level randomized studies showed no benefit to motorized spinal decompression compared the natural history of improvement of low back pain. Favorable studies were 1 randomized study and 6 low level IV studies. One study was a case study – see Mayo clinic report – of complication leading to urgent surgery (below).

TOTAL: 14 4 + 1 review of 10

5 Studies

9 Studies

0 Studies

1 level II

6 level I

0 Studies

CONCLUSION: Motorized spinal decompression – including VAX-D and DRX9000 is of no benefit over the natural history of improvement of common low back pain, and does have some risks associated.

Very Poor Predictive value for low back pain improvement over natural resolution of common low back pain.

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VAX-D, DRX900 and other Motorized Spinal Decompression Therapies
Studies Favorable: Total 5

Level IV: 4 Studies

1. Restoration of disk height through non-surgical spinal decompression is associated with decreased discogenic low back pain: a retrospective cohort study.
Apfel CC, Cakmakkaya OS, Martin W, Richmond C, Macario A, George E, Schaefer M, Pergolizzi JV.

SOURCE: Perioperative Clinical Research Core, Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California, USA.

BACKGROUND: Because previous studies have suggested that motorized non-surgical spinal decompression can reduce chronic low back pain (LBP) due to disc degeneration (discogenic low back pain) and disc herniation, it has accordingly been hypothesized that the reduction of pressure on affected discs will facilitate their regeneration. The goal of this study was to determine if changes in LBP, as measured on a verbal rating scale, before and after a 6-week treatment period with non-surgical spinal decompression, correlate with changes in lumbar disc height, as measured on computed tomography (CT) scans.

METHODS: A retrospective cohort study of adults with chronic LBP attributed to disc herniation and/or discogenic LBP who underwent a 6-week treatment protocol of motorized non-surgical spinal decompression via the DRX9000 with CT scans before and after treatment. The main outcomes were changes in pain as measured on a verbal rating scale from 0 to 10 during a flexion-extension range of motion evaluation and changes in disc height as measured on CT scans. Paired t-test or linear regression was used as appropriate with p < 0.05 considered to be statistically significant.

RESULTS: We identified 30 patients with lumbar disc herniation with an average age of 65 years, body mass index of 29 kg/m2, 21 females and 9 males, and an average duration of LBP of 12.5 weeks. During treatment, low back pain decreased from 6.2 (SD 2.2) to 1.6 (2.3, p < 0.001) and disc height increased from 7.5 (1.7) mm to 8.8 (1.7) mm (p < 0.001). Increase in disc height and reduction in pain were significantly correlated (r = 0.36, p = 0.044).

CONCLUSIONS: Non-surgical spinal decompression was associated with a reduction in pain and an increase in disc height. The correlation of these variables suggests that pain reduction may be mediated, at least in part, through a restoration of disc height. A randomized controlled trial is needed to confirm these promising results. CLINICAL TRIAL REGISTRATION NUMBER: NCT00828880.

2. Treatment of 94 outpatients with chronic discogenic low back pain with the DRX9000: a retrospective chart review.
Macario A, Richmond C, Auster M, Pergolizzi JV.

SOURCE:Department of Anesthesia and Health Research & Policy, Stanford University School of Medicine, Stanford, California 94305-5640, USA.

BACKGROUND: This study’s goal was a retrospective chart audit of 100 outpatients with discogenic low back pain (LBP) lasting more than 12 weeks treated with a 2-month course of motorized spinal decompression via the DRX9000 (Axiom Worldwide, Tampa, FL, U.S.A.).

METHODS: Patients at a convenience sample of four clinics received 30-minute DRX9000 sessions daily for the first 2 weeks tapering to 1 session/week. Treatment protocol included lumbar stretching, myofascial release, or heat prior to treatment, with ice and/or muscle stimulation afterwards. Primary outcome was verbal numerical pain intensity rating (NRS) 0 to 10 before and after the 8-week treatment.

RESULTS: Of the 100 initial subjects, three withdrew their protected health information, and three were excluded because their LBP duration was less than 12 weeks. The remaining 94 subjects (63% female, 95% white, age = 55 (SD 16) year, 52% employed, 41% retired, LBP median duration of 260 weeks) had diagnoses of herniated disc (73% of patients), degenerative disc disease (68%), or both (27%). Mean NRS equaled 6.05 (SD 2.3) at presentation and decreased significantly to 0.89 (SD 1.15) at end of 8-week treatment (P < 0.0001). Analgesic use also appeared to decrease (charts with data = 20) and Activities of Daily Living improved (charts with data = 38). Follow-up (mean 31 weeks) on 29/94 patients reported mean 83% LBP improvement, NRS of 1.7 (SD 1.15), and satisfaction of 8.55/10 (median 9).

CONCLUSIONS: This retrospective chart audit provides preliminary data that chronic LBP may improve with DRX9000 spinal decompression. Randomized double-blind trials are needed to measure the efficacy of such systems.

3. Systematic literature review of spinal decompression via motorized traction for chronic discogenic low back pain.
Macario A, Pergolizzi JV.

SOURCE:Department of Anesthesia, Stanford University School of Medcine, Stanford, California 94305-5640, USA.

OBJECTIVE: The objective of this study was to systematically review the literature to assess the efficacy of nonsurgical spinal decompression achieved with motorized traction for chronic discogenic lumbosacral back pain.

DESIGN: Computer-aided systematic literature search of MEDLINE and the Cochrane collaboration for prospective clinical trials on adults with low back pain in the English literature from 1975 to October 2005. Methodologic quality for each study was assessed. Studies were included if the intervention group received motorized spinal decompression and the comparison group received sham or another type of nonsurgical treatment.

RESULTS: Data from 10 studies were fully analyzed. Seven studies were randomized controlled trials using various apparatus types. Because of this low number, we also analyzed three nonrandomized case series studies of spinal decompression systems. As the overall quality of studies was low and the patient groups heterogeneous, a meta-analysis was not appropriate and a qualitative review was undertaken. Sample sizes averaged 121 patients (range 27-292), with six of the seven randomized studies reporting no difference with motorized spinal decompression and one study reporting reduced pain but not disability. The three unrandomized studies (no control group) of motorized spinal decompression found a 77% to 86% reduction in pain.

CONCLUSIONS: These data suggest that the efficacy of spinal decompression achieved with motorized traction for chronic discogenic low back pain remains unproved. This may be, in part, due to heterogeneous patient groups and the difficulties involved in properly blinding patients to the mechanical pulling mechanism. Scientifically more rigorous studies with better randomization, control groups, and standardized outcome measures are needed to overcome the limitations of past studies.

4. Outcomes after a prone lumbar traction protocol for patients with activity-limiting low back pain: a prospective case series study.
Beattie PF, Nelson RM, Michener LA, Cammarata J, Donley J.

SOURCE:Program in Physical Therapy, Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.

OBJECTIVE: To determine outcomes after administration of a prone lumbar traction protocol.

DESIGN: Prospective, longitudinal, case series.

SETTING: Suburban, chiropractic practice.

PARTICIPANTS: A total of 296 subjects with low back pain (LBP) and evidence of a degenerative and/or herniated intervertebral disk at 1 or more levels of the lumbar spine. We excluded patients involved in litigation and those receiving workers’ compensation.

INTERVENTION: An 8-week course of prone lumbar traction, using the vertebral axial decompression (VAX-D) system, consisting of five 30-minute sessions a week for 4 weeks, followed by one 30-minute session a week for 4 additional weeks.

MAIN OUTCOME MEASURES: The numeric pain rating scale and the Roland-Morris Disability Questionnaire (RMDQ) were completed at preintervention, discharge (within 2 weeks of the last visit), and at 30 days and 180 days after discharge. Intention-to-treat strategies were used to account for those subjects lost to follow-up.

RESULTS: A total of 250 (84.4%) subjects completed the treatment protocol. On the 30-day follow-up, 247 (83.4%) subjects were available; on the 180-day follow-up, data were available for 241 (81.4%) subjects. We noted significant improvements for all postintervention outcome scores when compared with preintervention scores (P<.01).

CONCLUSIONS: Traction applied in the prone position using the VAX-D for 8 weeks was associated with improvements in pain intensity and RMDQ scores at discharge, and at 30 and 180 days after discharge in a sample of patients with activity-limiting LBP. Causal relationships between these outcomes and the intervention should not be made until further study is performed using randomized comparison groups

5. Sudden progression of lumbar disk protrusion during vertebral axial decompression traction therapy.
Deen HG Jr, Rizzo TD, Fenton DS.

SOURCE:Department of Neurosurgery, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.

ABSTRACT: Vertebral axial decompression (VAX-D) is a form of spinal traction that is widely promoted as an effective and safe treatment of degenerated and herniated lumbar intervertebral disks. Information targeted at the general public emphasizes that the treatment is completely risk-free. We describe a patient with a large lumbar disk protrusion who experienced sudden, severe exacerbation of radicular pain during a VAX-D therapy session. Follow-up magnetic resonance imaging of the lumbar region showed marked enlargement of the disk protrusion, and urgent microdiskectomy was required. To our knowledge, this is the first reported complication of VAX-D therapy. This case shows that VAX-D therapy has the potential to cause sudden deterioration requiring urgent surgical intervention.
[PubMed - indexed for MEDLINE]


Randomized, controlled clinical trials. Researchers would use a computer program to randomly assign patients with back pain into two groups of 20. The first group (placebo group known as the control) would drink water (that only tasted like pomegranate juice but was not) for 10 days. The second group would drink real pomegranate juice for 10 days. None of the patients would know if they were drinking the real pomegranate juice or not. (This is called a blinded study). Then a researcher who does not know which person drank what (which now makes this a what’s called a “double blinded” study) would interview the patients to determine if their back pain was reduced, worsened or stayed the same. After this was all done, the information about which patients drank what would then be revealed. One could then see if those who drank the real pomegranate juice were better or not than the water drinking group.


Non-randomized, prospective comparative study. A researcher looks at 40 patients medical records to select 20 patients for the pomegranate drinking group and 20 patients for the control group who will drink water. This is called a “cohort,” namely a control and experimental patient make a cohort. Here the researcher may introduce his own bias whether he intends to or not. If he believes pomegranate is a safe, effective treatment for back pain then whether he means to or not he may put the healthier patients with less back pain in the pomegranate group and patients complaining of more back pain in the water-drinking group. (This particular bias is called “selection bias.” See section on types of research bias.)


Retrospective (already occurred) comparative study or case controlled study (each “experimental“ patient is matched to a patient that never had the experimental). This is not a reliable standard for determining one treatment over another, though it can be helpful to, say, see how many complications a certain treatment has. Researchers do a retrospective study for example reviewing 20 patient records of patients who reported they have been drinking pomegranate juice in the past and then 20 patients who have not reported drinking pomegranate juice. Then the researchers review the patients’ medical records determine if the back pain was reported better, worse or stayed the same. Here again, the selection process may introduce bias intentionally or not. In this case it may not only be selection bias, but could involve “recall” bias, or “expectation bias” or “attention bias.” (See Bias in Research section).


Case series do not determine success or failure of a treatment compared to other treatments or no treatment at all. Researchers or a physician does a case study on 20 patients who drink pomegranate juice for 10 days and then report the results. In this case there is no control group or comparison to patients who are not drinking pomegranate juice. It does not take into consideration that back pain could get better in 10 days if the patient takes nothing at all for the pain. These studies are easier and cheaper. They can be of value to determine better methods of doing a particular treatment, or what the complications of a certain treatment are, but NOT for determining if one treatment is better than another.


Expert opinion. One physician expert’s opinion on if pomegranate juice helps reduce back pain. No original research is conducted. Instead, just a written opinion or editorial that may talk about other research and give opinions, but no clinical study is conducted. AME considers this to be one step above hearsay for determining one treatment over another, though it may be valuable for stimulating discussion and ideas on a particular topic.

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