By Editorial Staff
Immediate Hypoalgesic and Motor Effects After a Single Cervical Spine Manipulation
Objective: The purpose of this study is to investigate the immediate effects of a single cervical spine manipulation and a manual contact intervention (MCI) on pressure pain thresholds (PPTs) and thermal pain thresholds over the elbow region and pain-free grip (PFG) force in patients with lateral epicondylalgia (LE).
Methods: A repeated measures, crossover, single-blinded randomized study was done. Ten patients with LE (5 female) aged from 30 to 49 years (mean, 42; SD, 6 years) participated in this study. Subjects attended 2 experimental sessions on 2 separate days at least 48 hours apart. At each session, participants received either a manipulative intervention or MCI assigned in a random fashion. Pressure pain threshold and hot and cold pain thresholds (HPT and CPT, respectively) over the lateral epicondyle of both elbows was assessed preintervention and 5 minutes postintervention by an examiner blinded to the treatment allocation of the patients. In addition, PFG on the affected arm and maximum grip force on the unaffected side were also assessed. A 3-way analysis of variance (ANOVA) with time (pre-post) and side (ipsilateral, contralateral to the intervention) as within-subjects variable and intervention (manipulation or MCI) as between-subjects variable was used to evaluate changes in PPT, HPT, CPT, or PFG.
Results: The ANOVA detected a significant effect for time (F = 37.2, P < .001) and a significant interaction between intervention and time (F = 25.1, P < .001) for PPT levels. Post hoc revealed that the manipulative intervention produced a greater increase of PPT in both sides when compared with MCI (P < .001). The ANOVA did not detect significant effects for time (F = 2.7, P > .2), intervention (F = 2.8, P > .2), or side (F = 0.9, P > .4) for HPT. Again, no significant effects for time (F = 0.8, P > .4), side (F = 0.6, P > .4), or intervention (F = 0.8, P > .5) was found for CPT. Finally, a significant interaction between intervention and time (F = 9.4, P = .004) and between time * side * intervention (F = 18.2, P < .001) was found for grip force. Post hoc analysis revealed that the cervical manipulation produced an increase of PFG on the affected side as compared with the MCI (P < .001).
Conclusion: The application of a manipulation at the cervical spine produced an immediate bilateral increase in PPT in patients with LE. No significant changes for HPT and CPT were found. Finally, cervical manipulation increased PFG on the affected side, but not the maximum grip force on the unaffected arm. Future studies with larger sample sizes are required to examine the effects of thrust manipulation on PPT, HPT, CPT, or PFG.
A Comparison of the Torsional Stiffness of the Lumbar Spine in Flexion and Extension
Objective: The main mechanism of injury to the spine is torsion, especially when coupled with compression. In this study, the in vitro torsional stiffness of the lumbar spine segments is compared in flexion and extension positions by cyclic and failure testing.
Methods: Fifteen lumbar spines were sectioned from fresh cadavers into 15 L2/3 and 15 L45 motion segments. Each vertebral segment was then potted superiorly and inferiorly in polymethylmethacrylate, effectively creating a bone-disk-bone construct. The potted spinal segments were mounted in a mechanical testing system, preloaded in compression to 300 N, and axially rotated to 3° in both directions at a load rate of 1°/s. This was done over three cycles for each motion segment in the flexion and extension positions. Each specimen was then tested to torsional failure in either flexion or extension. Stiffness, torque, and energy were determined from cyclic and failure testing.
Results: The results showed that in all cases of cyclic testing, the higher segment extension resulted in higher torsional stiffness. In relative extension, the lumbar specimens were stiffer, generated higher torque values, and generally absorbed more energy than the relative flexion condition. There were no differences found in loading direction or failure testing.
Conclusions: Increasing the effective torsional stiffness of the lumbar spine in extension could provide a protective mechanism against intervertebral disk injury. Restoration of segmental extension through increasing the lumbar lordosis may decrease the strain and reinjury of the joints, which can help reduce the extent of pain in the lumbar spine.
Interexaminer Reliability of T2-Weighted Magnetic Resonance Imaging for Lumbar Bright Facet Sign
Objective: The aims of this study were to characterize the bright facet response within the lumbar spine, to identify a constellation of findings associated with the response, and to quantify the interexaminer agreement on the previous objectives.
Methods: A retrospective study of lumbar magnetic resonance images obtained on 105 (N = 105) adult subjects (62 men and 43 women; age range, 18-84 years; mean age, 46.51 ± 16.01 years) reviewed by two musculoskeletal radiologists for the presence of high signal within the facet articulations (bright facet response) on fast spin echo T2-weighted images.
Results: Of the 630 lumbar facet articulations imaged (L3/L4 through L5/S1), 340 (54%) and 346 (55%) respectively, per examiner, did show a bright facet response. Interexaminer agreement with respect to the level and grading of a bright facet response was almost perfect with k ranging from 0.85 to 0.91 (SE, 0.06). Prevalence of bright facet responses averaged 40.5% at L5/S1, 56.5% at L3/L4, and 66.5% at the L4/L5 level. There was an association with degenerative facet and disk changes.
Conclusion: The bright facet response was a common phenomenon on T2-weighted magnetic resonance imaging of the lumbar spine in these cases. There was sufficient agreement with respect to the presence and extent of the bright facet response to conclude that the examiners' determinations were not made by random chance. There exist sufficient repeatability and reliability that a single descriptive term can be applied to unify the bright facet response: the bright facet sign.
Spinal Curves and Health: A Systematic Critical Review of the Epidemiological Literature
Objective: The purposes of this study were to (1) determine whether sagittal spinal curves are associated with health in epidemiological studies, (2) estimate the strength of such associations, and (3) consider whether these relations are likely to be causal.
Methods: A systematic critical literature review of epidemiological (cross-sectional, case-control, cohort) studies published before 2008, including studies identified in the CINAHL, EMBASE, Mantis, and Medline databases, was performed using a structured checklist and a quality assessment. Level of evidence analysis was performed as outlined by van Tulder, et al. (Spine 2003;28:1290-9), and the strength of associations were determined using the procedure outlined by Hemingway and Marmot (BMJ 1999;318:1460-7). Quality of the included articles were assessed by our own scoring system based on the Strengthening the Reporting of Observational Studies in Epidemiology checklist. Studies scoring maximum points (4/4 or 3/3) were considered to be of higher quality.
Results: Fifty-four original studies were included. We found no strong evidence for any association between sagittal spinal curves and any health outcomes including spinal pain. The included studies were generally of low methodological quality. There is moderate evidence for association between sagittal spinal curves and 4 health outcomes as follows: temporomandibular disorders (no odds ratios [ORs] provided), pelvic organ prolapse (OR, 3.18; 95% confidence interval [CI], 1.46-96.93), daily function (OR range, 1.8-3.7; 95% CI range, 1.1-6.3), and death (OR, 1.40; 95% CI, 1.08-1.91). These associations are however unlikely to be causal.
Conclusion: Evidence from epidemiological studies does not support an association between sagittal spinal curves and health including spinal pain. Further research of better methodological quality may affect this conclusion, and causal effects cannot be determined in a systematic review.
Social Communication Skills of Chiropractors: Implications for Professional Practice
Objective: Social communication skills are critical in the health professions. The aim of this study was to measure and identify professional practice predictors of social communication skills of practicing chiropractors.
Methods: The study population was derived from a group of doctors of chiropractic who participated in a practice-based research program. Participating chiropractors agreed to complete a survey detailing the chiropractor's sex, years in practice, practice type, size of the practice community, typical weekly practice volume, and an instrument to measure skills of social communication. Regression analysis was applied to identify associations between independent variables and responses to the social skills instrument.
Results: Results suggested that selected characteristics of clinical practice may be associated with clinician's social skills of communication. The weekly volume of patients to the practice emerged as a salient explanatory factor of overall social communication skills and as a factor individually for dimensions of social expressivity and social control. The practice arrangement (solo vs. group) proved important in terms of respondent emotional control scores. Similarly, the solo vs. group practice variable was associated with higher levels of emotional sensitivity; however, this association was mediated by the sex of the doctor of chiropractic; men reported lower levels of emotional sensitivity than women.
Conclusion: The findings of this study suggest associations between dimensions of social communication skills, practice characteristics, practice arrangements, and sex that may inform the efforts of educators as they endeavor to better prepare health professionals for practice in a wide spectrum of settings.
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JMPT abstracts are reprinted with permission from the latest (October/November 2008) issues of the journal. For complete journal contents, visit www.mosby.com/jmpt.