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Letters and Responses |
I was interested to read the recent article by Maluf et al titled "Use of a Classification System to Guide Nonsurgical Management of a Patient With Chronic Low Back Pain" (November 2000). The authors correctly stated that there are "potential benefits to using a classification approach to guide identification and treatment of symptom-provoking movements and postures." However, given the widespread recognition of a very similar, but more comprehensive, classification system proposed by McKenzie 20 years ago,1 I would question how Maluf and colleagues' proposal contributes further to our current understanding. McKenzie's Mechanical Diagnosis and Therapy (MDT) model1 first demonstrated the value of utilizing symptom-provoking-and-relieving movement and posture testing in assessing and classifying painful spinal disorders. Additionally, the major elements of both the MDT assessment and classification system have already been shown to yield measurements with interexaminer reliability.2–7
Both philosophies recognize that daily repetition of direction-specific postures and movements contributes to the development and recurrence of mechanical low back pain. Maluf et al recommended limiting motion in those directions identified as aggravating, but they did not discuss the possibility that exploring repeated motion in the opposite direction or another direction may also be beneficial in decreasing or eliminating pain.
There is abundant literature reporting that patients not only have a directional "vulnerability" (to flexion most commonly), they also have a directional "preference" that can be identified with the MDT examination, namely the use of repeated end-range loading of the symptomatic spine while monitoring the symptom response.8–15 The patients' pain typically centralizes and abolishes when they perform therapeutic movements and postures that honor and match their directional preference found during their assessment.
While Maluf et al reported that their patient's pain "localized" to the spine during treatment, they avoided the term "centralization"—a well-described and extensively used term in the low back pain literature2,11,12,16–25 and a phenomenon that has been reported in multiple studies16,17,19,20,22,24 to be a very reliable predictor of outcome. Utilizing the MDT classification, Maluf and colleagues' patient neatly meets the following criteria:
I agree with Maluf et al that classification of patients into homogenous subgroups has the potential to improve the management of low back pain. However, I suggest that their classification system would not meet the criteria laid down by the Quebec Task Force28 or Riddle's recommendations for new classification systems.29 Surely there could be real benefits in facilitating communication among therapists rather than adding further to the growing number of systems that appear to be based on incomplete understanding of McKenzie's classification by mechanical evaluation.
We all have much work to do!
Nelson, New Zealand
References
The purposes of our case report were (1) to introduce a system of LBP classification that previously had not been detailed in the literature and (2) to describe a patient's response to an intervention that was appropriate for the specific category of LBP she demonstrated. Although Watson has correctly noted that there are similarities between our proposed classification scheme and McKenzie's MDT approach, there also are key differences.3 We have incorporated these differences into our system because we believe they are important for both the classification and the management of many patients with LBP. Before addressing the other issues raised by Watson, we will briefly review the key differences.
Differences: Both our examination and the MDT examination include tests of symptoms with different direction-specific positions and movements of the lumbar spine.1,4 For example, we include assessments of the presence and effect of lumbar rotation alignments and movements on the patient's symptoms in several different positions (standing, sitting, supine, hook lying, prone, quadruped). Based on descriptions available in the literature, the MDT approach does not include direct tests of lumbar rotation or side bending. Instead, the MDT approach includes trunk side gliding, a movement considered by McKenzie to be a combined movement of rotation and side bending.1(p38) Because small amounts of repeated rotation have been found to produce microscopic injury to spinal tissues5 and we have observed that patients repeatedly perform small amounts of rotation to perform daily activities, we believe a detailed assessment of lumbar rotation is warranted. Whether the MDT test of trunk side gliding in standing provides the same information obtained with the tests of lumbar rotation that we use remains to be tested.
Our examination also includes assessment of lumbar spine motions that occur during limb movement and the effect of the limb-induced spinal motions on the patient's symptoms. In our opinion, assessment of symptom-provoking motions of the lumbar spine that occur during movement of the extremities may provide critical information about the impact of using the extremities during functional activities (eg, reaching overhead, crossing the legs while sitting). To our knowledge, the MDT examination does not assess the impact of the limbs on lumbar motion or LBP symptoms.
Finally, neither our examination nor our intervention includes the use of the repeated spinal movements advocated by the MDT approach. We seek to confirm the direction-specific spinal movements and positions that contribute to the patient's LBP by performing tests in several different positions, rather than with repeated spinal movements in the same position. In our system, tests that produce symptoms may be repeated, but only for the purpose of determining how the position or movement can be modified to alleviate symptoms.3 For example, our patient's LBP classification was rotation with extension because (1) the patient's symptoms were consistently reproduced with different extension and rotation alignments and with movements in several positions and (2) the patient's symptoms were consistently decreased or eliminated by restricting rotation or extension alignments within a position.
Our approach classifies patients' conditions according to the lumbar movement dysfunction identified during the examination (ie, primary direction of spinal alignment or motion consistently associated with an increase in symptoms).3,4 We believe that categories based on the movement dysfunction help to direct treatment, because we believe the spinal alignments and motions that exacerbate symptoms should be avoided. Categories named for the movement dysfunction have the further advantage of reflecting the unique expertise of physical therapists.6 In contrast to our approach, an underlying pathoanatomic origin is assumed for each of the categories in the MDT system of classification (eg, disk pathology is assumed in derangement syndrome).1 Such assumptions, however, cannot be confirmed using the tools available to physical therapists.
Our treatment approach assumes that the repetition of direction-specific postures and movements performed throughout each day contributes to the development, persistence, or recurrence of mechanical LBP.2 Therefore, our approach is designed to emphasize the reduction of cumulative stress on low back tissues through what we think are strategies designed to limit the offending lumbar positions and movements during performance of daily activities. Impairments of muscle force and joint flexibility that potentially contribute to the lumbar movement dysfunction also are addressed. By comparison, McKenzie's approach reflects the assumed pathoanatomic origin of low back-related symptoms. For example, Watson suggests that the patient described in our case report demonstrated posterolateral derangement based on the distribution and behavior of her symptoms during the examination. The MDT treatment strategy for posterolateral derangement would emphasize repetition of lumbar extension movements in order to promote anterior migration of a presumed posterolateral displacement of the nuclear mass. According to our approach, the patient was classified as having a lumbar rotation with extension movement dysfunction.2 This classification was based on our observations of a consistent increase in the patient's symptoms that appeared to be associated with rotation and extension alignments and movements of the lumbar spine, as well as a consistent decrease or elimination of the patient's symptoms when the same symptomatic alignments and movements were restricted. In our view, repeated lumbar extension exercises would have exposed symptomatic low back tissues to increased levels of cumulative stress and, therefore, were contraindicated in this case.
Watson also discusses the potential for repeated motion in the opposite direction to the motions found to aggravate the patient's symptoms to decrease or eliminate her LBP. Although there is evidence to support the efficacy of repeated spinal movements in reducing low back–related symptoms in some patients,7–12 it is our opinion that the type of patient with LBP who might benefit from this type of treatment is still not fully understood. In our opinion, it is not clear whether the repetition of end-range spinal movements could expose low back tissues to unnecessarily high levels of stress, thereby predisposing these tissues to injury. This concern would be of particular importance in the treatment of patients having diagnosed pathology of the lumbar spine, such as the patient described in our case report who had degenerative disk and joint disease. We have observed that restriction of symptom-provoking postures and movements most often is sufficient to decrease or eliminate low back–related symptoms, without the need to encourage repeated movements of the spine in the opposite direction. In cases where restriction of the movement dysfunction does not decrease the patient's symptoms immediately during examination, we have found taping or other stress-reducing techniques to be an effective adjunct to treatment.
Other Issues:Watson states that patients display a directional "vulnerability," primarily into flexion, as well as a directional "preference" that can be identified through the use of repeated end-range loading of the spine. As a point of clarification, we refer to the patients' tendency to move the lumbar spine in a particular direction with various trunk and limb movements as their directional "predisposition,"3 and this directional predisposition typically is associated with an increase in their symptoms. Thus, Watson's use of the term movement "vulnerability" is synonymous with our reference to a patient's directional "predisposition" to movement. We also have observed that many of the patients with LBP we have examined displayed a directional predisposition to movement in extension or rotation. Additionally, similar to the patient described in our case report, many patients with LBP display a predisposition to movement in more than one direction.13
Watson notes that we avoided the use of the term "centralization" and instead reported that the patient's pain "localized" to the spine with treatment. We chose not to use the term "centralization" to describe the patient's change in pain location for two reasons. First, we wanted to avoid the use of terminology that might be associated with any particular approach to treatment. Second, in examining the peer-reviewed literature, we found that aspects of the definition of centralization varied across studies.7–12 In an effort to avoid confusion, therefore, we chose to describe the changes in symptom intensity and location that the patient reported. Interestingly, the only tests that evoked the patient's thigh symptoms were active hip extension in a prone position. Restriction of the lumbar extension and pelvic rotation observed with the tests of hip extension resulted in elimination of the patient's symptoms.4(p1103) We believe it is noteworthy that, in this patient with chronic LBP, (1) both short- and long-term improvements were observed in her symptoms and function, and (2) the improvements were maintained with a management program that did not include repeated end-range spinal movements. As Watson noted, our findings are consistent with those of other researchers7–12 who reported the prognostic value of changing the location of a patient's symptoms during an examination. What remains to be fully tested is the question of which methods should be used with which type of patients to attain a positive change in symptom location.
There is no question that the system of classification for LBP described in our case report has not been shown to meet all of the criteria outlined by the Quebec Task Force14 or by Riddle.2 We add, however, that the same is true for existing systems of classification.2 We believe that improved understanding of the issues related to diagnosis and management of patients with LBP is best facilitated through continued testing, reporting of results, and critical appraisal of all perspectives.
References
Mr Watson contends that the classification scheme used in the case report is of little value because "...given the widespread recognition of a very similar, but more comprehensive, classification system proposed by McKenzie 20 years ago, I would question how Maluf et al and colleagues' proposal contributes further to our current understanding." I would remind Mr Watson that popularity and longevity are insufficient reasons for thinking an intervention has value. Perhaps one reason why others are developing their own classification schemes is because after 20 years there is no body of literature to support the efficacy and effectiveness of the McKenzie scheme that Mr Watson so thoroughly endorses. Should we assume that because we have interventions we should stop developing new approaches? How can we believe that a classification-based approach is sufficient when there is minimal evidence and, more importantly, no clear-cut data to show its superiority to other approaches? Had our peer reviewers and editors believed that the approach used by Maluf and colleagues did not represent best or even good practice, we would not have published the paper. Judgments such as that, however, must be based on research, and currently there is no research that indicates the superiority of the McKenzie approach.
This is a commentary on the case report of Maluf et al1 in which they presented the use of a classification system to guide the management of a patient with chronic low back pain. One of the study's authors, Dr Sahrmann, wrote in 1988, that "physical therapists must establish diagnostic categories that direct their treatment prescriptions and that provide a means of communication both within the profession and with other practitioners and consumers about the conditions that require their particular expertise for effective treatment and prognostication."2(p1706) The authors should be commended because the diagnostic categories presented in the recent case study are a very important step towards defining physical therapy diagnosis categories. I have framed my commentary on this study within the context of the Diagnostic and Statistical Manual for Physical Diagnosis (DSM-PD).3 (See Table.) The DSM-PD is a proposed model for physical therapy diagnosis with the goal of facilitating clinical treatment, research, and education.
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Maluf et al are also to be commended for publishing their inclusion criteria for these categories, as this makes them open to scrutiny and discussion. I agree with the second and third criteria given by Maluf et al as inclusion criteria for lumbar extension dysfunction, namely, that symptoms occur or increase with the lumbar spine positioned or moved into extension and disappear or decrease with restriction of lumbar extension. However, I would tend not to agree with their first inclusion criterion that describes the tendency for the lumbar spine to move in the direction of extension with movements of the spine and extremities. Many people with symptoms performing a specific movement of the spine guard against that movement during function. Perhaps in the future we will see that there are several categories within lumbar extension dysfunction each describing specific symptom reproducing movements, symptom reproducing functions, or associated movement patterns.
Perhaps others could publish their criteria in this case report format, which does not require as much formal testing. To their credit, in the earlier study by Delitto et al,4 the authors did not report in the case report format, but in a study on the prescriptive validity of the extension-mobilization category. However, the case report format allows for faster communication and discussion of what the most useful diagnostic categories might be. More rigorous testing and study of these categories (as in the Delitto et al article) would be encouraged by the publication of these categories in case reports.
Under Axis II, the impairments listed by Maluf et al do not reflect any segmental spinal joint mobility deficits. Physical therapists who look into segmental joint deficits might evaluate and treat lumbar extension dysfunction differently. Ten years from now, there might be Axis I disorders that further distinguish lumbar extension dysfunction into categories with myofascial, joint, and/or coordination-organization causes. Each category would then guide treatment.
By having several inclusion criteria, Maluf et al are describing syndromes. Syndromes are what physical therapy diagnosis should consist of. This is completely different from a simple listing of impairments and handicaps. The description and classification according to syndromes promotes research on more homogeneous sample populations. For example, it promotes the study of the effects of treatments on lumbar extension dysfunction rather than low back pain.
In this case report, there might be other Axis III medical diagnoses that would guide treatment. For example, if this patient had osteoarthritis in the hip joint that limited hip extension, instead of a shortening of the hip flexor muscles, the prognosis and the treatment would be different. The medical diagnosis does assist in guiding physical therapy treatment, but the physical therapy diagnosis is the true guiding force.
The reporting of the modified Oswestry score as Axis IV is a point for discussion only. There are many functional rating scales for disorders of particular body parts and for specific disease processes. However, something like the global assessment of function for mental disorders would be better. Physical therapists could assess function using a global scale—but using the global scale as it relates to the Axis I physical therapy diagnosis.
We have made a little progress since 1984 when the APTA House of Delegates passed the motion that "physical therapists may establish a diagnosis within the scope of their knowledge." If we compare the development of physical diagnosis categories to mental diagnosis categories, we see that we are in the very beginning stages, perhaps where psychology was 50 years ago. The article by Maluf et al is a step in the right direction. The profession needs to establish physical therapy diagnostic categories, and the APTA should take a leading role in promoting their formation. A task force should be started by the APTA to look into diagnostic categories and how the Association could promote their development. The development over time would be toward categories that are valid, perhaps according to some of the guidelines reported by Riddle.5 Perhaps this could be in a DSM-PD type format. Perhaps it could be part of the Guide to Physical Therapist Practice. This is a process that will take decades, and the time to begin is now.
Manhattan Beach, Calif
References
We agree with Maeda that physical therapy would best be served by the use of diagnostic category names that specify the primary movement problem instead of treatment-based category names.2 We believe that, as a profession, we are still in the early stages of describing the clinically relevant clusters of patient types. An agreement to label categories based on the primary movement dysfunction would allow us to (1) more readily identify the similarities and differences among the diagnostic groupings described by our many clinical experts and (2) focus on making the treatment consistent with the problem. We disagree with Maeda that the low back pain (LBP) categories we have proposed should be described as only "symptom-based." We consider the category names we have proposed to be broader in nature, specifying the patient's primary movement problem.2 For example, our patient had a number of movement system impairments (eg, pelvic rotation with hip rotation in a prone position) and symptoms that indicated that lumbar rotation with extension was the primary movement dysfunction.
Our first inclusion criterion for the lumbar rotation with extension category was: "Tendency for the lumbar spine to move in the direction of rotation and extension with movements of the spine and extremities. Lumbar spine alignment tends to be extended and rotated relative to neutral with the assumption of postures."1 Maeda made the argument that, because patients guard against movements in the directions associated with symptoms, our first criterion is inappropriate. We included the criterion because the primary assumption underlying our classification system is that LBP is the result of the lumbar spine's predisposition to a specific pattern of movement when either the trunk or the limbs move. We assume that the tendency of the lumbar spine to move in a specific pattern is a consequence of habits formed during performance of everyday activities. The repeated assumption of specific postures and the repeated use of specific movement strategies are proposed to lead to changes in the relative flexibility of tissues that contribute to development of excessive or prolonged loading of tissue, resulting in microtrauma and eventually LBP.3
We believe that (1) patients exhibit direction-specific patterns of movements and positions of the spine across the various tests of the examination and (2) the direction-specific patterns are often associated with an increase in symptoms. For example, our patient did not report increases in symptoms solely when asked to move or assume a position of lumbar extension or rotation. She also reported an increase in symptoms, and she exhibited tendencies to move or position herself into lumbar extension and rotation with several different test positions (eg, quadruped) and movements (eg, hip rotation).1(pp1102–1103) We believe that some patients may guard against several movements in loaded positions in the very early phases or the very late phases of a severe low back injury. In such cases, we believe that performing the tests in unloaded positions (eg, hook lying, prone over pillows, quadruped) minimizes patient discomfort and provides a better opportunity for the clinician to identify the primary movement dysfunction.
We found Maeda's description of the Diagnostic and Statistical Manual for Physical Diagnosis (DSM-PD),4 modeled after the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-IV),5 to be an interesting perspective. In fact, at the American Physical Therapy Association's Combined Sections Meeting in 1997, one of our colleagues presented an overview of the development of the DSM and several other classification systems used in various disciplines.6 One of the most important things we learned from her review of the DSM-IV is that the developers were able to make substantive advances only after they decided to abandon references to etiology in the descriptions of disorders and instead focused on operational definitions (and labels) for abnormal behaviors.7 Because it often is just as difficult to determine the exact etiology of conditions like LBP as it is to determine the etiology of mental disorders, we think that the approach of relying on descriptions of behavior that was adopted by psychiatry also has merit for physical therapy. We believe our system is consistent with this view. At a minimum, we believe review and discussion by our profession of the on-going process used by the psychiatric profession to develop, test, and refine the DSM-IV would be a worthwhile endeavor.
References
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