On “Treatment-Based Classification System for Low Back Pain: Revision and Update.” Alrwaily M, Timko M, Schneider M, et al. Phys Ther. 2016;96:1057–1066.

We would first like to congratulate the authors on their update of the treatment-based classification (TBC) system.¹ As we attempt to move forward in finding the most appropriate path for the clinical management of low back pain (LBP), it's critical to reflect on the systems we utilize and make appropriate adjustments and improvements when and where they are warranted. We are hopeful that the statement regarding “more convergence than divergence” among the systems indicates a scientific readiness to work together in the future for improved patient outcomes.

We do feel compelled, however, to correct inaccuracies with several of the statements made. First, the cited reference for the categorical statement that “TBC is the most extensively researched classification system in the field of physical therapy”^1(p1058) is the 2012 article by Karayannis et al.² Examination of this reference reveals no substantiation of this claim or indeed any statement or insinuation that comes close to supporting it. In fact, none of the aims of the review by Karayannis et al were to establish the “extensiveness” of the research regarding the different classification systems, and hence the search strategy would not have been structured in a way to achieve such a goal. The fact that more articles were retrieved for the TBC system than for other systems did not appear intended to reflect the extensiveness of the research; it was merely a total in this targeted search with other explicit study aims in mind. Any conclusions regarding the extensiveness of research would clearly need to have been derived from a search with that specific objective in mind. An example of this would be the search strategy detailed in the protocol for an upcoming systematic review of the McKenzie method for chronic LBP.³ It is quite likely that an alternative conclusion would be reached if such a strategy were used to compare the “extensiveness” of research for each classification system. Suffice it to say, the number of articles exploring the various aspects of the McKenzie method, including centralization and directional preference, is many times that found in the review by Karayannis et al.

Second, the introduction states, “No single system is comprehensive enough in considering the various clinical presentations of patients with LBP.”^1(p1058) This statement is contrary to findings in the literature that demonstrate that clinicians are able to use the McKenzie system to classify all of their patients, either into the mechanical syndromes or into the McKenzie system's “other” subgroups in a wide variety of clinical settings.^4–6 As is true for the TBC system, the MDT classification system also has been updated and clarified since the publication of the updated texts in 2003.⁷

We also would like to make a clarification in relation to the statement made regarding the shortcomings of the current classification systems in addressing psychosocial factors. The implication is that none of the systems adequately address these factors, and hence there is need for a system that can achieve this aim. We would like to bring to the authors' and readers' attention the literature that explores the effect of use of the McKenzie system on psychosocial factors. Studies have shown that fear avoidance,^8–11 fear and disability beliefs,^9,11 somatization,¹² and depressive symptoms¹² are all significantly reduced with a McKenzie system intervention, with pain self-efficacy being increased.¹⁰ These issues may be addressed directly by the education principles of empowerment, by the reassurance, or by the self-treatment focus and patient-centered approach that the McKenzie system provides,⁸ or they may be secondary to the patient experience of the positive effect of movement on pain, improving self-confidence and assurance. It is clear that either directly or indirectly the McKenzie system has substantial evidence that it does successfully address these issues identified as barriers to recovery and so is clearly a system that is fundamentally biopsychosocial.

Investigating classification systems as a means of matching patient subgroups to intervention is clearly a priority, but while we are each exploring a particular system, care should be taken not be dismissive of or ignore the research that had been accumulating with other systems that present viable alternatives.

• © 2016 American Physical Therapy Association