Design: Blinded SEMG assessments with the patients standing upright, fully flexed and extended at the trunk, and measures of pressure pain thresholds (PPT) were made after four tests administered by another examiner.
Setting: The research was conducted on patients in a private chiropractic practice.
Patients: A convenience sample of 10 of the practitioner's most acute LBP patients without neurological deficit were asked to participate and none refused. Six patients without recent LBP volunteered as controls.
Main Outcome Measures: Present myoelectric indicators included: thoracolumbar asymmetry (T-L/A: first seen in an earlier pilot study), loss of flexion/relaxation (F/R) at L3, contralateral responsivity (increased myoelectric activity opposite the side of leg pain) and right/left asymmetry (R-L/A) at L3.
Results: Significant differences between groups were seen in T-L/A (p=.04) and R-L/A [data averaged from three postures (p=.04)], and robust group differences were seen in F/R (p=.011 right; p=.026 left). Contralateral responsivity was not significant. Loss of F/R was the only indicator that correlated with diminished PPT (r=.52 right; r=.46 left) and with Oswestry disability (r=.42), and that negatively correlated, as expected, wtih straight leg raising (r=-.50 right; r=-.74 left).
Conclusions: Results support use of the technique to detect muscle dysfunction related to LBP. Further research of SEMG correlations with measures of the manipulable lesion is warranted.
DATA SOURCES: On-line search of MEDLINE, key words, radiograph and X ray in combination with cervical spine (vertebrae); the Chiropractic Research Archives Collection (CRAC); indexes published in the Journal of Chiropractic Research; conference proceedings from Annual Biomechanics Conference of the Spine, FCER sponsored conferences and Annual Upper Cervical Spine Conference; references identified from bibliographies of pertinent articles; a telephone poll of radiography/technique instructors at chiropractic colleges.
STUDY SELECTION: Techniques that quantitatively assess relative alignment of skeletal structures or distortion of the spinal column.
DATA EXTRACTION: Techniques were grouped according to the structures analyzed and the views used.
DATA SYNTHESIS: Variables and artifacts that limit the reliability or validity of static cervical X-ray line drawing analysis were identified and the techniques assessed for their reported reliability and validity.
CONCLUSIONS: Reliability studies exist showing that inter- and intraexaminer reliability are sufficient to measure lateral and rotational displacements of C1 to within + or - 1 degree. This amount of error allows objective analysis of upper cervical X rays to detect changes in the angular positional relationships of radiographic images on the order of those already seen clinically. Methods of cervical analysis that use relative angular measures of skeletal positioning are best able to control the effects of radiographic distortion. The accuracy of the analysis methods has not been ascertained to establish the extent to which angular measurement of vertebral relationships actually reflect three-dimensional movement. It is not known how much of the changes that are seen in pre/post-radiograph sets are due to positioning changes of the patient between radiographic procedure, and how much are due to actual changes of skeletal relationships brought about by adjustment.
Some authors have emphasized the need for continuous EMG monitoring throughout a range of motion as opposed to static exams for assessment. Allen first discovered the phenomenon of flexion-relaxation (F/R: a period of relative inactivity of the erector muscles in the lumbar spine on flexion of the trunk past 63 degrees +/- 13 degrees) utilizing surface EMG over 40 years ago and continuous monitoring.
However, in contrast, the use of surface EMG scanning as it is currently employed in chiropractic practice has been termed experimental at a recent conference on standards of care. Some EMG distributors have suggested that left/right differences in EMG activity at a spinal level is evidence of a subluxation, that a single sample (instantaneous or integrated by various methods) is adequate at each spinal level, and that preparation with an alcohol abrade only is adequate for skin preparation.
Meeker et al recently utilized a distributor's protocol to attempt to detect differences in left-right erector spinae asymmetry in the lumbar spine, but found no differences at L3 or L5 with patients prone or sitting. Their sample size, and the mild nature of pain in the group with LBP were cited as reservations.
The present investigation, then, was an attempt to determine whether EMG surface scanning at the end-ranges of back motion can be a useful tool to detect back pain or erector spinae m. dysfunction. This work attempted to overcome a number of problems cited in earlier studies, by using repeat measures, better skin preparation, and patients with more robust levels of LBP, and is an extension of a pilot study we completed in April 1990 on 17 subjects.
Several chiropractic methods have been developed to assess cervical curvature and attempt its normalization, based on the assumption of some idealized normal curve. The only published trial of the effects of chiropractic adjustment on CHK was an unblinded retrospective study performed in 1983. That work suggested that chiropractic adjustment can have a positive effect on cervical curve abnormalities. The current study is an attempt to corroborate and extend those early findings.