Efficacy of VAX-D on chronic low back pain: Study of dosage regimen
Gustavo Ramos M.D., Department of Neurology 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).

1 | 2 | 3 | 4 | 5 | 6

return to LCD Research page