A new report on spinal injections prepared for the Agency for Healthcare Research and Quality (AHRQ) underscores the challenges facing the Department of Health and Human Services as it seeks to rationalize the nation's health care investment.

The use of epidural injections soared 271%  and facet joint injections by 231% among Medicare benficiaries between 1994 and 2001, increasing from $24 million to more than $175 million. Newer data puts the growth rate at 187% between 2000 and 2008, but evidence of effectiveness is inconsistent.

AHRQ commissioned the Pacific Northwest Evidence-based Practice Center to undertake a systematic review of the published evidence for the agency's Technology Assessment Program looking at the effectiveness of epidural, facet joint and sacroiliac corticosteroid injections on low back pain. The report, "Pain Management Injection Therapies for Low Back Pain" summarizes the evidence, evaluates inconsistencies in the evidence and identifies evidence gaps.

The authors’ data included 78 trials of epidural injections, 13 trials of facet joint injections, and one trial of sacroiliac injections. Patients in these trials all suffered some form of back pain, and their results were compared to placebo interventions. The authors solicited input from "key informants" representing specialties considered to be end users of the research, with John Carrino  M.D., M.P.H, from Johns Hopkins Hospital representing radiology.

In place of a Technical Expert Panel, CMS provided input to key questions posed to the panel, including: How does effectiveness vary according to use of imaging guidance or route of administration (e.g. for epidural injections interlaminar, transforaminal, caudal for epidural injections and for facet joint injections intra-articular, extra-articular [peri-capsular] or medial branch injections)? Other questions probed medications used, patient characteristics that predicted outcomes, harms and research methodologies.

The bulk of the evidence reviewed was on epidural corticosteroid injections, and the authors conclude that when treating radiculopathy, the injections had a small, but noticeable impact on pain and function. However, there was no impact on the long-term risk of surgery.

Evidence was limited when looking at epidural corticosteroid injections for treating spinal stenosis or nonradicular back pain, but the data showed no impact on pain, function or likelihood of surgery.

In addition, the authors found no evidence that facet joint corticosteroid injections were effective. Data about sacroiliac corticosteroid injections was insufficient.  

No evidence was found to indicate that greater benefits could be derived based on the specific epidural technique, use of fluoroscopic guidance, specific corticosterioid, dose, or number or frequency of injection. Better patient selection could result in better value, the authors surmised, but they acknowledged more research will be needed to accurately make such determinations.