spinal stenosis
Chronic low back pain (CLBP) remains a challenging condition to manage, one that carries a significant socioeconomic burden. There are a plethora of non-surgical treatments for CLBP, which can overwhelm stakeholders such as patients, third party payers, health care providers, researchers, and policy makers. Although all involved should strive for the most effective treatment that utilizes minimal health care resources, there is often clinical uncertainty as to which treatment is most appropriate for the individual patient.
In order to better understand the state of existing literature on non-surgical treatments for CLBP, the North American Spine Society sponsored a special focus issue of The Spine Journal. This review of the McKenzie method was one of the papers featured in this issue. An executive summary of background information and pertinent findings will be presented in this review.
Terminology/History of the McKenzie Method:
• in 1958, the basis for the technique was discovered accidentally, when a patient with leg symptoms inadvertently lay prone in an extended position for about 10 minutes, after which he reported to McKenzie that his leg had not felt as good for weeks
• studies on the McKenzie method began in 1990, including many studies that have been done on the concept of centralization
• the McKenzie method includes both an assessment and an intervention component (NOTE: commonly in general practice and research, the term "McKenzie" is incorrectly applied when referring only to the application of extension exercises)
• the assessment component aims to classify the patient into one of three syndromes, and is commonly referred to as Mechanical Diagnosis and Therapy (MDT)
• the main objective of the assessment is to achieve a pattern of pain response called "centralization"
• Centralization: refers to the sequential and lasting abolition of distal referred symptoms, and subsequent reduction/elimination of spinal pain in response to a single direction of repeated movements or sustained postures
• Directional Preference: refers to a particular direction of lumbosacral motion or sustained posture that cause symptoms to centralize, decrease, or even disappear while the individual's spinal motion simultaneously returns to normal
General Description:
The overall objective of the McKenzie method is patient self-management, which includes three important phases:
1. Educating and demonstrating to patients the benefits of positions and end range movements on their symptoms, and the aggravating effects of the opposite positions.
2. Educating patients in methods to maintain the reduction and elimination of their symptoms.
3. Educating patients how to regain full function of the lumbar spine without symptom recurrence.
Additional Points:
• McKenzie noted that the value of a single direction of movement is frequently not apparent unless repeated a number of times to end range (it should be noted that often the initial attempts in a particular direction may increase symptoms)
• provided that each direction of lumbar motion is tested repeatedly and to end-range, a directional preference can normally be identified
• a regular McKenzie assessment includes a full medical history and physical examination, including assessment of response to repeated lumbar movements
Utilizing this information, patients can be classified into one of three mechanical syndromes proposed by McKenzie:
1. Derangement Syndrome: has the distinctive pain response of centralization with a directional preference.
2. Dysfunction Syndrome: found only in patients with chronic symptoms, characterized by intermittent pain produced only at end range in a single direction restricted movement. Unlike derangement, there is no rapid change in symptoms or ROM as a result of performing repeated motions.
3. Postural Syndrome: typically not seen in chronic LBP, is intermittent in nature, located in the midline and is provoked by sustained slouch sitting. Symptoms are typically abolished by correction of sitting posture (normally restoration of lumbar lordosis).
Management According to McKenzie Syndrome Classification:
• Derangement Syndrome: aim is to rapidly centralize and eliminate all symptoms while restoring normal lumbar motion
• Dysfunction Syndrome: treatment is intentionally aimed at reproducing the symptoms at end range so that the short, painful structure can be adequately lengthened in order to heal and become pain-free over time
• Postural Syndrome: education is aimed at improving posture, which will remove undue physical stress from involved tissue and improve symptoms
• it is important to note that each patient requires individualized exercises, and no generic prescription of exercises will suffice
• for a minority of patients, generally those with chronic LBP, the end range force they can generate will be insufficient to eliminate pain - in these instances, clinicians can provide manual assistance/pressure to the movements, and even progress to spinal manipulation/mobilization in the patient's directional preference
Evidence Surrounding the McKenzie Method and Centralization:
• at least six studies have demonstrated that centralization is a positive prognostic factor for LBP (i.e. those who "centralize" with a particular movement or direction have better outcomes)
• in fact, a recent systematic review1 on centralization concluded that, when elicited, centralization predicts a high probability of positive treatment outcome when treatment is guided by assessment findings
• two studies have demonstrated that centralization is a more important prognostic indicator than fear-avoidance and work-related issues
• further, failure to change pain location on assessment (non-centralization) has been shown to be a poor prognostic indicator and a predictor of poor behavioral response to spinal pain
• although seemingly evident, in the literature there is some indication that those patients with mechanical LBP that is affected by posture will respond favorably to directional exercises
• in many published clinical guidelines, the interventional component of the McKenzie method has been mentioned, while the assessment component has been overlooked
• two systematic reviews2,3 on the McKenzie method have been conducted - both concluding that there was limited evidence relating to chronic LBP, but also suggesting that small benefits were noted versus a variety of comparison treatments
• a third systematic review4 on physical therapy-directed exercise interventions after classification by symptom response methods (included mixed duration LBP patients), concluded that exercise implemented based on patient response was significantly better than control or comparison interventions (4/5 studies investigated McKenzie method, all scored 6+ on PEDro scale indicating high quality)
• studies investigating the reliability of the McKenzie assessment have produced mixed results - further studies are required
• there are numerous ongoing studies on the McKenzie method, including subgroup determination in CLBP, clinical prediction rules, comparative prognostic value studies, anatomical studies, and treatment RCTs
Conclusions & Practical Application:
The McKenzie method certainly has a role to play in the overall assessment and management of low back pain. It has the potential to reliably classify patients into groups based on directional preference, which have distinctly different treatment and self-management needs. It is relatively simple, and straightforward in its approach. Considering the recent emphasis in the literature on sub-grouping LBP patients in the context of a Clinical Prediction Rule (which does include a category for directional exercise), research attention paid to the McKenzie method, MDT, and the centralization phenomenon should continue to rise. Such classification approaches can help guide clinical decision making, and improve treatment outcomes for LBP patients.
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