Do Spinal Injections in the Treatment of Degenerative Disc Disease offer Value?

31st Annual Meeting of the North American Spine Society Highlight

The recent Agency for Healthcare Research and Quality (AHRQ) Assessment, although highly rigorous, may not be truly reflective of the entire evidence base regarding injections, according to Dr. Matthew Smith in a presentation on the value of injections for lower back pain at the 2016 North American Spine Society (NASS) Meeting.
Needle syringe with liquid coming outThe presentation included a thorough look at the question of the value of injections for lower back pain.Matthew J. Smith, MD, EMHL is a practicing physical medicine and rehabilitation physician whose presentation at NASS included a thorough look at the question of the value of injections for lower back pain. He reviewed the AHRQ’s assessment, the NASS response to the AHRQ assessment, and a response by Roger Chou, MD, the lead author of the AHRQ assessment to NASS. He also reviewed the 2016 National Institute for Health and Care Excellence (NICE) guidelines, a 2008 Cochrane review and Novitas Solutions local coverage determination (LCD) for epidural injections in pain management.

“The LCD by Novitas is more of a true reflection of what multiple stakeholders agree is the appropriate use of epidural injections (EIs) in our patients,” Dr. Smith said. In November of 2016, Novitas determined that it was reasonable to perform injections on patients who had back pain without lower extremity symptoms if they had a failure of 4 weeks of nonsurgical, non-injection care with additional criteria. Additionally, patients needed a documented VAS or number pain rating scale (NPRS) ≥ 3/10 (moderate to severe pain) or functional impairment in ADLs, and pain associated with a substantial imaging abnormality. The imaging abnormalities included a central disc herniation or high-intensity zone; severe degenerative disc disease or central spinal stenosis; or discogenic pain.

Technology Assessment From The Agency for HealthCare Research and Quality
Dr. Smith discussed an assessment entitled “Pain Management Injection Therapies for Lower Back Pain” prepared for the AHRQ in 2015.  The conclusions differed significantly from Novitas. The authors concluded, “Limited evidence suggested that epidural corticosteroid injections are not effective for spinal stenosis or nonradicular back pain and that facet joint corticosteroid injections are not effective for presumed facet joint pain.” They also concluded that “there was insufficient evidence to evaluate the effectiveness of sacroiliac joint corticosteroid injections.”

“The assessment for the AHRQ is an analysis of randomized studies of which 78 are on epidurals, 13 are on facet injections, and 1 was on sacroiliac joint injections. A meta-analysis was performed on outcomes, including pain, function, and risk of surgery,” Dr. Smith explained.

NASS Responds to the AHRQ Assessment
According to Dr. Smith, there were three key areas that NASS commented on regarding the AHRQ technology assessment, including diagnostic ambiguity, injection technique, and statistical analysis.

Diagnostic Ambiguity
NASS felt that diagnostic etiologies were inappropriately combined in the report which included 22 specifics for radicular pain, while 6 had a mixture of radicular and back pain and 1 was specific for back pain. In their December 15, 2014, response NASS states, “Investigations of targeted injection therapies based on patients with a specific anatomic diagnosis repeatedly demonstrate high success rates for clinically meaningful changes in back pain and disability.”

Injection Technique
In the AHRQ assessment, of the 29 randomized controlled trials providing evidence of efficacy of epidural steroid injections compared to placebo, there were only 7, which were fluoroscopically guided while 22 were performed blind. According to NASS the consideration that nonspecific injections are equal to image guided injections is inappropriate.

Statistical Analysis
NASS also contends that the statistical use of the mean of continuous data for pain and function, which the authors of the AHRQ Assessment performed, is invalid. “The use of mean data is not in accordance with the NIH Task Force recommendation for research standards for chronic low back pain,” Dr. Smith explained. “It mandates a normal Gaussian distribution, which is infrequent in these patient populations given the floor and ceiling effects of a pain scale.”

Roger Chou, MD Comments
According to Dr. Smith, the lead author of the AHRQ Assessment responded to questions about the report in The BackLetter published in November of 2015. The lead author, Roger Chou, MD stated that observational studies “are susceptible to confounding and bias even when they are well done.” He also talked about the use of continuous data and said that there were no differences when they looked at dichotomous outcomes rather than continuous outcomes.

Dr. Chou also addressed diagnosis. “We assessed the findings to determine whether results were better based on the method used to select patients, including the use of diagnostic blocks and other methods. We found no pattern suggesting that this is the case.”

A Different Era
Dr. Smith concluded by talking about the change to a more reductionist era in which the medical community is trying to solve their problems with the use of numbers and data. “I feel like there is something that gets lost in the translation,” he said. “By requiring the level of rigor set in the AHRQ assessment, the bar is so high that almost no treatments are supported. It is difficult to assess subgroup effects, the effects of comorbidities and the effects of concurrent treatments such as behavioral change and physical conditioning. As physicians, if we rely solely on evidence from randomized controlled studies, we may wind up doing a disservice to our patients.”

Disclosures: Dr. Matthew J. Smith disclosed he is a consultant for Inflexxion.

To view additional meeting highlights from the 31st Annual Meeting of NASS, click here.

Updated on: 02/27/18
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