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

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 anti-inflammatory 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.

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.

1 | 2 | 3 | 4 | 5

return to LCD Research page