The single randomized controlled trial of spinal decompression therapy compared the VAX-D® unit, which places the patient a prone rather than supine position, to transcutaneous electrical nerve stimulation (TENS) for the treatment of chronic low back pain. Subjects were recruited through advertisement and had chronic low back pain of greater than 3 months duration with associated leg pain. Disc protrusion or herniation confirmed by CT or MRI was also required. Average duration of pain in the study population was 7.3 years and average age was 42 years old. This study enrolled 44 patients and 40 completed the study. Patients were randomized in sequential order to their appropriate group. Outcome measures were the 10 centimeter visual analog pain scale (VAS) and a disability scale. The disability scale rated the subject’s ability to perform their most affected activity on a 0 to 4 scale, with 4 being “can do without limitation”. Treatments consisted of 30 minute sessions, five times per week for four weeks followed by weekly sessions for 4 weeks. The control group received TENS for 30 minutes daily for 20 days followed by weekly treatment for 4 weeks. Both groups were able to take anti-inflammatory and non-narcotic pain relievers as needed. Success of treatment was defined by 50% improvement in VAS and any improvement in disability. At the conclusion of the study 13 out of 19 (68.4%) of the treatment group showed improvement while 0 of 21 for the TENS group. At follow-up 7 of the original 19 subjects (36.8%) in the treatment group showed sustained improvement.
Sherry E, Kitchener P, Smart R. A prospective randomized controlled study of VAX-D and TENS for the treatment of chronic low back pain. Neurol Res 2001; 23(7):780-784.