Intraarticular Facet Injections for Low Back Pain: Design Considerations, Consensus Methodology to Develop the Protocol for a Randomized Controlled Trial.

Background: Since the publication of guidelines by the UK National Institute for Health and Care Excellence (NICE) and the American Pain Society guidelines for low back pain in 2009 there have been deep divisions in the pain treatment community about the use of therapeutic intraarticular facet joint injections. While evidence for the effectiveness or not of intraarticular facet joint injections remains sparse, uncertainty will remain. The Warwick feasibility study, along with a concurrent study with a different design led by another group, aims to provide a stable platform from which the effectiveness and cost effectiveness of intraarticular facet joint injections added to normal care could be evaluated in randomized controlled trials (RCTs).

Objectives: To reach consensus on key design considerations for the Warwick facet feasibility study from which the study protocol and working manuals will be developed.

Study Design: A consensus conference involving expert professionals and lay members.

Methods: Preliminary work identified 5 key design considerations for deliberation at our consensus conference. Three concerned patient assessment and treatment: diagnosis of possible facet joint pain, interaarticular facet joint injection technique, and best usual care. Two concerned trial analysis: a priori sub-groups and minimally important difference and are reported elsewhere. We did systematic evidence reviews of the design considerations and summarized the evidence. Our design questions and evidence summaries were distributed to all delegates. This formed the basis for discussions on the day. Clinical experts in all aspects of facet joint injection from across the UK along with lay people were invited via relevant organizations. Nominal group technique was used in 15 facilitated initial small group discussions. Further discussion and ranking was undertaken in plenary. All small group and plenary results were recorded and checked and verified post conference. Where necessary participants were contacted via email to resolve outstanding issues.

Results: Fifty-two delegates attended the conference with lay people and all relevant professions represented. Consensus was reached on the details of how to assess patients for facet joint pain, undertake the injections, and deliver usual care. Where post conference checking of results revealed errors in calculating ranking results on the day, consensus was reached by email consultation. All but 3 delegates agreed to be associated with the outcome.

Limitations: Allocating one day for discussing a wide range of topics imposed time pressure on discussion and calculation of the numerous rankings.

Conclusions: Through the use of an evidence-based, systematic, inclusive, and transparent process we have established consensus from expert health professionals in the UK, with lay input, on the clinical assessment of suspected facet joint pain, interaarticular injection for facet joint pain, and best usual care for use in a feasibility study for a proposed pragmatic clinical trial of interaarticular facet joint injections. This provides a strong basis for a clinical trial that will be acceptable to the pain treatment community.