Research Review By Dr. Jeff Muir©

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Date Posted:

August 2013

Study Title:

The relative effectiveness of segment specific level and non-specific level spinal joint mobilization on pain and range of motion: Results of a systematic review and meta-analysis

Authors:

Slaven EJ, Goode AP, Coronado RA, et al.

Author's Affiliations:

University of Indianapolis, Indianapolis, USA.

Publication Information:

Journal of Manual and Manipulative Therapy 2013; 21(1): 7-17.

Background Information:

Passive joint mobilization techniques are frequently used by clinicians to assess and treat spinal disorders (1, 2). Clinically, mobilizations have demonstrated value as a diagnostic tool (3, 4) and an effective treatment modality, especially when combined with exercise programs (5). When combining therapies in this manner however, it becomes problematic (from a research perspective) to delineate the relative contribution of spinal mobilizations to clinical outcomes.

In a 2008 systematic review by Schmid et al. (6), 15 studies investigating the effects of spinal mobilization alone on pain measures and range of motion were assessed. The pooled results suggested that joint mobilization was responsible for approximately 20% of improvement in outcomes, as compared to controls who did not receive mobilization. Clouding the issue, though, is the observation that mobilizations at both symptomatic and asymptomatic levels were associated with similar beneficial results (7). In addition, other studies have shown that one session of mobilization had little or no lasting effect (8).

The current systematic review was therefore undertaken to examine the effects of a single session of joint mobilization in symptomatic subjects, performed at any spinal region, on changes in self-reported pain at rest and with the most painful movement. A secondary purpose of this study was to compare the changes in pain that occur when a single session of joint mobilization is provided to a specific, or a nonspecific level of symptoms within the same spinal region.

Pertinent Results:

From an initial pool of 1237 articles, 17 were selected for comprehensive review, with only 8 remaining eligible for inclusion in the final analysis.

Due to the heterogeneity of the results from the included studies, it was not possible to combine these results. As such, a meta-analysis could not be performed. Smaller subgroups however, were able to be combined to evaluate the outcome of joint mobilization at specific and non-specific levels in the same spinal region. Homogeneity for combining studies with an overall estimate was set a priori at an alpha level of p = 0.15. A higher p-value was chosen to test for heterogeneity since these tests have low power, particularly when there are few studies analyzed.

Specific vs. Non-Specific Mobilization:

Six RCTs compared specific level versus non-specific level mobilization. Of these six studies, four measured the outcome of pain with the NRS and two with the VAS. The four studies using the NRS were eligible for meta-analysis and meta-regression. The two studies that measured pain with the VAS were analyzed separately.

Pain at Rest:
For NPS: significant overall heterogeneity was noted (p = 0.075). The individual pooled mean difference for the cervical spine was 20.41 [95% confidence interval (CI): 20.86–0.03]. The individual pooled mean difference [0.29 (95% CI: 20.06–0.64)] for the lumbar spine was in the direction opposite to that of the cervical spine. A large, significant (p = 0.02) difference of 0.71 (95% CI: 0.13–1.28) was found between these two means, indicating that the effect from mobilization in the cervical spine differs from that of the lumbar spine, with cervical mobilization favoring specific level mobilization, while non-specific level mobilization appears to be superior in the lumbar spine.

For VAS: mean differences were found to fall on both sides of the null value. These two studies were found to be statistically homogenous (p = 0.189) with an overall mean difference of 0.92 (95% CI: -3.94–5.78).

Pain during most painful movement:
For NPS scale: the overall homogeneity was p = 0.279. The difference between the cervical and lumbar estimate was large [0.61 (95% CI: 20.01–1.24)] although not significantly (p = 0.05) different from one another.

For VAS scale: estimates again fell on both sides of the null. In addition, these estimates demonstrated significant heterogeneity (p = 0.131) and were substantially imprecise. As such, no overall estimate was produced.

Clinical Application & Conclusions:

Multiple studies provided evidence that a single session of joint mobilization can lead to a reduction of self-reported pain at rest and self-reported pain with the most painful movement. The studies supporting this statement were methodologically strong.

Important with regards to the patient’s experience and symptomology is the methodological approach that resulted in only studies that analyzed the immediate effects of mobilization, as opposed to the effects several days following treatment, being included in this review. With the passage of time, it becomes more difficult to attribute the immediate changes in self-reported pain at rest and self-reported pain with the most painful movement solely to the mobilization provided. As such, the findings of this paper are of particular importance to clinicians, as it provides support for the use of mobilizations as a pain-relieving modality as opposed to one focused solely on improving mobility. Further, the effect of mobilization relating to a specific level or non-specific level(s) was different based on the region of the spine being treated. In the cervical spine, the direction of effect was toward specific mobilization (being more effective) and in the lumbar spine towards non-specific mobilization. This may reflect our overall ability to be level-specific in these spinal regions, but more research is required to fully describe this concept. Having said that, I think most practicing clinicians would agree that our ability to mobilize or manipulate a specific segment may be greater in the cervical spine versus the lumbar spine.

Study Methods:

Search strategy:
A systematic literature search was performed for relevant articles in MEDLINE (1966 to October 2010), CINAHL (1983 to November 2010), and PEDro for randomized controlled trials (RCTs) on the immediate effects of joint mobilization to the spine in symptomatic subjects. Search terms included ‘manual therapy’, ‘joint mobilization’, ‘joint mobilisation’, ‘spinal manual therapy’, ‘manipulation therapy’, ‘low back pain’, ‘thoracic pain’, ‘cervical pain’, ‘randomised controlled trial’, and ‘randomized controlled trial’. Searches were limited to “human” studies and “English”.

Selection criteria:
Two authors (ES and EH) independently evaluated the potentially relevant studies for inclusion. RCTs investigating the effects of a single session of passive joint mobilization in subjects with current cervical, thoracic, or lumbar pain were deemed potentially relevant. For the purpose of this review, joint mobilization was defined as a non-thrust, oscillatory mobilization procedure directed at the spinal joints

Methodological quality:
Two reviewers (ES and EH) independently assessed the risk of bias in the included studies using criteria previously reported by Furlan et al (9).

Data analysis:
Studies with differing outcome measures (i.e. NRS vs. VAS) were analyzed in separate analyses. The 95% confidence limit difference (CLD), calculated as the upper confidence limit subtracted from the lower confidence limit, was used to determine the precision of mean difference, with smaller values indicating more precise estimates. All data analysis was completed using “Stata, version 11”.

Study Strengths / Weaknesses:

Limitations:
  • Only eight studies were found to be acceptable when methodological rigor was assessed, and of the eight, there was not one study completed on the thoracic spine. This is unfortunate, as the thoracic spine is often treated with mobilizations. Therefore, the lack of empirical evidence restricts the extrapolation of these findings to the thoracic spine.
  • There were a limited number of studies in each group, even when comparing findings for the lumbar and cervical spines.
  • There was a lack of clinical homogeneity between the studies included in each group.
Strengths:
  • The methodological quality of the included studies on the effectiveness of a single episode of mobilization on pain was high overall.

Additional References:

  1. Allison G, Edmonston S, Kiviniemi K et al. Influence of standardized mobilization on the posteroanterior stiffness of the lumbar spine in asymptomatic subjects. Physiother Res Int 2001; 6: 145–56.
  2. Powers CM, Kulig K, Harrison J, Bergman G. Segmental mobility of the lumbar spine during a posterior to anterior mobilization: assessment using dynamic MRI. Clin Biomech 2003; 18: 80–3.
  3. Abbott JH, McCane B, Herbison P et al. Lumbar segmental instability: a criterion-related validity study of manual therapy assessment. BMC Musculoskelet Disord 2005; 6: 56.
  4. Humphreys BK, Delahaye M, Peterson CK. An investigation into the validity of cervical spine motion palpation using subjects with congenital block vertebrae as a ‘gold standard’. BMC Musculoskelet Disord 2004; 5: 19.
  5. Gross AR, Goldsmith C, Hoving JL et al. Conservative management of mechanical neck disorders: a systematic review. J Rheumatol 2007; 34: 1083–102.
  6. Schmid A, Brunner F, Wright A, Bachmann LM. Paradigm shift in manual therapy? Evidence for a central nervous system component in the response to passive cervical joint mobilisation. Man Ther 2008; 13: 387–96.
  7. Kanlayanaphotporn R, Chiradejnant A, Vachalathiti R. Immediate effects of the central posteroanterior mobilization technique on pain and range of motion in patients with mechanical neck pain. Disabil Rehabil 2010; 32: 622–8.
  8. Hegedus E, Slaven E, Goode A, Butler R. The neurophysiological effects of a single session of spinal joint mobilization: does the effect last? J Man Manip Ther 2011; 19: 143–51.
  9. Furlan AD, Pennick V, Bombardier C, van Tulder M. 2009 updated method guidelines for systematic reviews in the Cochrane Back Review Group. Spine 2009; 34: 1929–41.