Beginning of series of blog posts comparing efficacy of McKenzie interventions and Core Stabilization for Treatment of Low Back Pain.
The Efficacy of McKenzie Versus Core Stabilization Treatment for Low Back Pain
Author: Peter J McGrath, PT, DPT.
The purpose of this research review is to analyze the effectiveness of McKenzie versus Core Stabilization physical therapy treatment for low back pain. A search was conducted for peer-reviewed journal articles consisting of randomized control trials published between the years 2004 to 2015, with keywords being ‘McKenzie’, ‘low back pain’, ‘core stabilization’, and ‘treatment’. 5 studies were selected for critical analysis, with 541 patients included. The results of this literature review provide greater support for the effectiveness of McKenzie physical therapy treatment as compared to core stabilization for reduction of low back pain and maximization of functional mobility in patients with low back pain. This is especially true for studies of shorter duration, and for patients who demonstrate a direction of preference.
Low back pain is a common occurrence in patients throughout the world. It is often linked with disability, psychosocial changes, and time missed from work (Walker, 2000). The prevalence of low back pain makes it an important topic of research in order to identify the most effective treatment methods to improve patient outcomes and maximize the efficient use of time and health care resources.
The McKenzie method, also known as Mechanical Diagnosis and Therapy (MDT), was developed in 1981 by Robin McKenzie, a physiotherapist from New Zealand. This approach involves an examination to classify patients into syndrome categories based on the clinical presentation of their symptoms, as well as syndrome-specific treatment involving instruction in exercises, postural correction, and self-management of symptoms.
A key component of MDT involves the clinician correctly identifying whether or not a patient demonstrates a direction of preference during initial evaluation and ongoing testing. If repeated motions in a specific direction are able to move the patient’s pain from distal to proximal, this is referred to as a centralization, which places a patient in the ‘derangement’ syndrome category, indicating presence of a bulging disc. Demonstration of direction of preference and centralization are considered to be favorable prognostic factors (Long, May, & Fung, 2008).
If a patient experiences pain in a constant location that is perceived at end ranges of a decreased range of motion, they are placed into the ‘dysfunction’ syndrome category which indicates adaptive shortening of tissues has taken place. A patient is placed into the ‘posture’ syndrome, which is associated with suboptimal alignment of the body, if they have normal range of motion but experience end-range pain in a constant location that is associated with prolonged positioning and disappears when force is removed and optimal alignment is restored. If a patient displays positive slump and upper limb tension tests, with intermittent peripheral symptoms that do not change during mechanical testing, they are classified as having ‘adherent nerve root’ syndrome (McKenzie & May, 2003). The rationale behind MDT as treatment for low back pain is that repeated motions into an established direction of preference, when combined with postural correction, can often help to improve range of motion, pain, and function by promoting a more symmetrical balance of forces around the involved joints of the spine. In turn these mechanical changes help to reduce adaptive shortening of soft tissue and promote optimal distribution of the semi-fluid nucleus pulposus centered within the intervertebral discs.
Core stabilization exercises are another commonly prescribed treatment for low back pain. The proposed mechanism of reduction of low back pain achieved through core stabilization exercises is that improvement of strength, endurance, and nervous system recruitment of abdominal and lumbar core musculature (primarily transverse abdominis and multifidi) allows for increased ability of the muscles to prevent shifting of the spine during upright mobility and when changing and maintaining body positions. As these muscles are able to provide more stability and support, the stress and passive stability that must be provided by connective tissue decreases, leading to reduction of low back pain. Core stabilization exercises often include isometric exercises performed within mid-range of motion or neutral spine position.
Treatment of low back pain has been an ongoing topic of research throughout the years, with many therapeutic approaches and philosophies being investigated. However, there continues to be opportunity for further advancement in treatment of this pathology, with the majority of patients experiencing low back pain reporting continuation of their symptoms for a duration greater than 1 year (Costa et al., 2012). The purpose of the current review is to determine the effectiveness of McKenzie versus core stabilization physical therapy treatments for low back pain.
Keywords searched include ‘McKenzie’, ‘core stabilization’, ‘low back pain’, and ‘treatment’. Results were narrowed to include studies published after 2004, in the English language, full-text, randomized controlled trials, referenced by other studies, and scholarly (peer reviewed) journals. Studies were excluded if they did not compare McKenzie interventions with core stabilization exercises, or were determined by the author of this literature review to not provide adequate detail required to critically assess their research methodology. 5 studies were selected and considered on-topic, with a combined total of 541 patients included.
The purpose of this paper was to investigate the effectiveness of McKenzie versus core stabilization physical therapy treatments for low back pain. A brief summary of significant findings is as follows. The first article indicated that when core stabilization is compared to improper prescription of McKenzie interventions, core stabilization is more effective. The second article provided significantly greater support for McKenzie interventions when compared to core stabilization in a patient population that demonstrated a direction of preference during initial evaluation. When compared to Back School interventions, McKenzie interventions were more effective at reducing disability and improving function for patients with low back pain persisting for 12 weeks or more. When compared to spinal stabilization interventions, both methods were found to effectively reduce pain and disability, however there were no statistically significant differences in final outcome measures, but the stabilization group showed greater improvements in passive supine straight leg raise and pain description. When compared to the Williams approach, McKenzie interventions were found to be more effective for reducing low back pain with a minimum duration of 3 weeks, increasing range of motion, and improving tolerance for the sitting position. A detailed description of all 5 included studies is provided below.
Hosseinifar, M., Akbari, M., Behtash, H., Amiri, M., & Sarrafzadeh, J. (2013) conducted a randomized controlled trial which investigated the effects of McKenzie versus core stabilization exercises for treatment of patients with chronic nonspecific low back pain. Chronic symptoms were defined as greater than 3 month duration. 30 patients were randomly assigned between 2 groups: 15 subjects in the McKenzie group and 15 subjects in the core stabilization group. Inclusion criteria for this study include age between 18 and 50 years, presence of chronic low back pain between the costal margin and buttocks, with or without reference to the lower extremity. Exclusion criteria for this study include recent history of fracture, trauma or previous surgery in the lumbar region; spondylolysis or spondylolisthesis, spinal stenosis, neurological disorders, systemic diseases, cardiovascular disease, pregnancy, receiving simultaneous treatment with physical therapy modalities or other therapies.
Subjects received 18 treatment sessions of 1 hour duration each, consisting of 3 times per week for 6 weeks. The interventions applied to the stabilization group consisted of a 6 stage progressive exercise program. Stage 1 consisted of segmental control exercises with emphasis on isolated contraction of individual muscles of transverse abdominis, multifidi, and pelvic floor muscles. Stage 2 involved segmental control exercises which emphasized the co-contraction of transverse abdominis, multifidi, and pelvic floor muscles together in supine, prone, and quadruped positions. Stage 3 consisted of closed kinetic chain segmental control exercises. Stage 4 involved open kinetic chain segmental control exercises. Stage 5 consisted of developing segmental control exercises in functional scenarios. Stage 6 involved co-contraction of transverse abdominis and multifidi muscles when an external load is applied, and implementing the co-contraction of transverse abdominis during light aerobic activities such as walking.
The results of this study were evaluated by an assessor who was blinded to the subjects’ group assignments. Data recorded include pain as measured by 0 to 100 visual analogue scale, disability as measured by the Persian version of the 10-item Functional Rating Index which uses a 5-point scale, and muscle thickness of transverse abdominis and multifidi musculature during rest and contraction as measured by ultrasound imaging. Motions utilized to elicit core contraction during imaging include abdominal draw in maneuver and active straight leg raise.
Both groups demonstrated significant reductions in low back pain at the p<0.05 level. Only the core stabilization group demonstrated significant reduction in disability score. The core stabilization group also yielded significantly greater increases in muscle thickness of right transverse abdominis during abdominal draw in maneuver, and the thickness of left transverse abdominis during active straight leg raise. Core stabilization also produced a change resting muscle thickness of left transverse abdominis.
Limitations of this study include significant exclusion factors such as age between 18 and 50 years, which limit the clinical applicability of the findings, as many patients in the clinic present with positive presence of these factors. A home exercise program was not established for the patients, limiting the efficacy of McKenzie interventions which are intended to be performed multiple times throughout every day, rather than 80-100 repetitions within 1 hour, 3 times per week. Furthermore, the study did not specify whether or not the clinicians who were treating with McKenzie interventions were credentialed to be proficient in this area of practice, which brings into question the inter-rater reliability. Additionally, the McKenzie interventions were not performed in a specific, established direction of preference. Instead they were performed with 4 exercises into lumbar extension and 2 exercises into lumbar flexion, without any mention or recognition of possibility of relevant lateral components. McKenzie interventions also traditionally include postural education and often involve patient education regarding use of lumbar roll in sitting for those who demonstrate direction of preference for lumbar extension, which was not mentioned in this study and therefore was presumably not incorporated into the interventions provided to the McKenzie group. Lastly, 18 sessions of 1 hour duration each, occurring 3 times per week, were utilized for delivery of interventions in this study, which limits the applicability of the study to clinical practice in the United States because this scheduling of patient visits is often prevented by reimbursement constraints.
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