Efficacy of flexion and extension treatments incorporating braces for low-back pain patients with retrodisplacement, spondylolisthesis, or normal sagittal translation.
Radiographic instability seemingly enjoys the status of a well-defined clinical syndrome. The concept is widely used, and specific treatments, usually spinal fusion, are routinely performed based on the diagnosis. The minimum standards necessary to establish radiographic instability as a legitimate clinical syndrome have not been established, however. The primary purpose of this study was to determine if treatment involving bracing, exercise, and education controlling either flexion or extension postures, would result in a distinctive pattern of favorable or unfavorable results, depending on the type of radiographic instability (retrodisplacement or spondylolisthesis). Fifty-six patients meeting strict study inclusion and radiographic evaluation criteria were assigned signed to a bracing treatment (flexion, extension, placebo-control) according to a randomization scheme, designed to ensure equal representation of translation categories (retro, normal, spondy) across treatment groups, and assessed at admission and 1-month follow-up. The sample was relatively evenly divided between men (46%) and women (54%), and by age. Translation classification was related to both gender and age, with men more likely classified as retro and women more likely spondy and patients in their 20s having lower incidence of spondy and higher incidence of normal translation. Translation classification was not related to selected indices of low-back pain history. Brace treatments were not shown to reduce patient range of motion or lessen trunk strength. A significant treatment by time interaction for the modified pain interference (VAS) scale indicated improvement for patients in extension compared with patients in flexion and control-placebo treatments. In conjunction with no significant three-way interaction between treatment, translation classification, and time, it was hypothesized that radiographic instability might more appropriately be considered a corroborative sign of advanced discogenic problems. Improvement in extension treatment, regardless of the type of radiographic abnormality, suggests that the treating clinician might consider extension treatment for chronic low-back pain patients. Causes and implications for the failure of this study to provide support for considering radiographic instability as a clinical syndrome are considered and future directions for this area of research suggested.