Single-motor-unit discharge characteristics in lumbar multifidus muscle of acute low back pain patients.

Acute low back pain (ALBP) causes rapid deterioration of paraspinal muscle function. The underlying neurophysiology is poorly understood. We therefore carried out this observational study in patients with ALBP to characterize motor unit (MU) activity in deep lumbar multifidus (LM) muscle and compare with our previous findings from pain-free subjects. Nine subjects (1 woman; age 26-59 yr) with ALBP duration of 1-21 days were recruited from outpatient clinics. Fine wire electromyography (EMG) electrodes were implanted bilaterally at the painful spinal level under computer tomography guidance. EMG was recorded during spontaneous sitting and standing, and during voluntary force production. Linear mixed models were utilized to test or control for the effects of a number of predefined variables. Compared with sitting, standing increased total duration of EMG activity, median MU discharge rate, interspike interval variability, and common drive measured as common drive coefficients (CDC) derived from concurrently active MU pairs. Median discharge rate in 73 MUs was 5.5 and 6.6 pulses per second (pps) during spontaneous sitting and standing, and 7.2 pps during voluntary force production. Interspike interval variability was lower during voluntary tasks than during spontaneous force production. Common drive was less pronounced in bilateral vs. unilateral unit pairs, also in spontaneous standing. This difference was not seen in our previous pain-free subjects, suggesting altered bilateral control of the spine in ALBP. The distribution of CDC values was not a homogeneous continuum but could be seen as two partially overlapping populations of CDC distributions.NEW & NOTEWORTHY We implanted fine-wire electrodes in the deepest part of axial postural muscles in patients with acute low back pain and characterized their motor unit activity. We found less pronounced common drive to the two sides of the spine compared with pain-free subjects, suggesting a different postural control strategy in patients with acute low back pain. An unexpected finding was that common drive coefficient values appeared to consist of two partially overlapping populations of normal distributions.

Precision implantation with positional confirmation of fine-wire EMG electrodes in the deep posterior neck muscles.

Precise electrode placement is essential for obtaining useful electromyographic (EMG) recordings. Our aim was to develop a protocol for computerized-tomography (CT) guided fine-wire (FW) electrode placement that permits confirmation of the final electrode position in the deep posterior cervical multifidus (CM). FW-EMG electrodes were custom-made from three 50-µm diameter Teflon-insulated platinum/iridium wires. The electrodes were inserted bilaterally in the CM in 15 healthy adult subjects through a 45-mm cannula under CT guidance. The final position of the electrode placement was confirmed in reconstructed 2D and 3D images. Electrode placement was within the fascial boundaries of the CM for 21 of the 25 successfully inserted FW-EMG electrodes. The distance from the electrode to the middle of the CM did not increase significantly with target depth until a breakpoint at 63.2 mm (95%CI 59.1-65.3), from where it increased by an additional 2.9 mm per mm increase in target depth (95%CI 1.3-6.6). Viable EMG was obtained from 21 electrodes. CT guided implantation provided excellent visual documentation in three dimensions of the final placement of the tip of the electrode bundle. The technique affords confidence in studies of motoneuron activity in CM.

Contextually Aided Recovery (CARe): a scientific theory for innate healing.

BACKGROUND: The chiropractic profession emerged when scientific explanations for causes of health and disease were still in infancy and the co-existence of notions such as innate healing and vitalism were perhaps admissible within such a historical context. Notwithstanding, within the scientific culture of the 21st Century all healthcare paradigms require evidential support which in regard these early concepts are in large part, absent. Nevertheless, a large body of emerging scientific evidence supports the existence of innate healing phenomena that may explain a plethora of clinical outcomes observed during chiropractic care. However, in contrast to the notion that removing the putative subluxation constitutes the mechanism by which this healing is initiated, the evidentially supported explanation is one that invokes the impact of contextual factors inherent in the skilful care and authority of the healthcare provider. This perspective is presented here as the scientific model of Contextually Aided Recovery (CARe). MAIN BODY: This paper contends that;Contextual effects are powerful and desirable and are triggered by contextual factors present in all therapeutic encounters including those encountered in chiropractic practice.These factors can elicit large clinical effects with substantive evidence supporting pain, immune and motor modulation.The compartmentalisation of specific and non-specific effects is a biologically and scientifically false dichotomy, erroneously invoked to de-legitimise treatment approaches that expertly construct contextual healing scenarios.The use of factors to construct contextual healing scenarios that maximise positive (placebo) and minimize negative (nocebo) effects is a skilful clinical art within the multimodal approach that describes modern chiropractic care and should be presented and defended as a legitimate component of orthodox healthcare Clinical improvement during chiropractic care, beyond any biologically specific treatment effects of manipulation and other modalities, may be largely understood considering contextual factors as described by a Contextually Aided Recovery (CARe) model.

Single-motor-unit discharge characteristics in human lumbar multifidus muscle.

The underlying neurophysiology of postural control of the lower back in humans is poorly understood. We have characterized motor unit (MU) discharge activity in the deep lumbar multifidus (LM) muscle in nine healthy subjects (20-40 yr, 3 females). Bilateral fine wire electrodes were implanted at L4 spinal level using ultrasound guidance. EMG was recorded during spontaneous sitting and standing and during voluntary force production. Individual MUs were analyzed with regard to instantaneous discharge rate, interspike interval variability, alternation of activity between MUs, and cross correlation between concurrently active MUs quantified by the common drive coefficient (CDC). Significant effects of sitting vs. standing were seen on median discharge rate and interspike interval variability. Median discharge rate in 71 units was 5.4 and 6.9 pulses/s during spontaneous sitting and standing and 7.4 pulses/s during voluntary force production. Several MUs fired doublets. CDC analysis of 87 MU pairs showed a significantly higher common drive in spontaneous than in voluntary activity and significant differences between unilateral and bilateral pairs, although not when spontaneously active in standing. In spite of common drive, MUs were recruited from inactivity to tonic discharge lasting for several minutes without changes in discharge rate in already active MUs, and several instances were documented where activity was rotated between MUs. We argue that this behavior is indicative of self-sustained discharge in LM motoneurons, establishing intrinsic motoneuron properties as a central mechanism for postural control of deep back muscles.

The psychometric profile of chiropractic patients in Norway and England: using and comparing the generic versions of the STarT Back 5-item screening tool and the Bournemouth Questionnaire.

BACKGROUND: Musculoskeletal pain and low back pain (LBP) in particular is one of the more costly health challenges to society. The STarT Back Tool (SBT) has been developed in the UK with a view to identifying subgroups of LBP patients in order to guide more cost effective care decisions. The Bournemouth Questionnaire (BQ) is a validated multidimensional patient reported outcome measure (PROM) that is widely used in routine clinical practice settings. This study sets out to describe and compare SBT and BQ scores within and between populations of patients presenting for chiropractic care in Norway and Great Britain. METHODS: Patient demographics, BQ and the 5-item generic condition SBT data were collected from patients presenting with musculoskeletal pain to 18 Norwegian and 12 English chiropractors. Analysis of correlation between groups was achieved using a 1-way Chi2 approximation (p < 0.05). RESULTS: Eleven percent of Norwegian LBP patients (n = 214) and 24% of English LBP patients (n = 186) were "distressed by their condition" (SBT > 4). By comparison, Norwegian chiropractic patients are: somewhat younger, have lower BQ scores, are less distressed by the condition and score significantly lower on items relating to catastrophisation and depression than English patients. There was an apparent association between total BQ and SBT scores (correlation 0.59, p < .0001) and patients who scored higher than 45 (IQR 39-58) on BQ were more likely to respond "distressed by condition" (>4) on SBT. Furthermore, patients in "distressed by condition" SBT category who had marked the "low mood" question on SBT also had a high score on the "depression" question of BQ (>6 (IQR 4-8), correlation 0.54, p < .0001). CONCLUSION: The BQ and SBT appear to identify the same subgroups in some, but not all of the measured items. It appears that unknown factors result in variations between patients seeking chiropractic care for comparable complaints in primary care in England vs Norway. Comparison of populations from Norway and UK demonstrate that extrapolating and pooling of data in relation to different populations should be done with caution, in regard to these stratification tools.

Increasing research capacity in the chiropractic profession: A case study and evaluation of an innovative research program in Norway.

OBJECTIVE: The subject of research methods is not commonly covered in continuing professional development (CPD) courses in spite of its emphasis in undergraduate education. This initiative aimed to develop postgraduate research competency and recruit chiropractors to musculoskeletal research. METHODS: The program was delivered as a university-based program with 20 credits over seven contact weekends covering topics of evidence-based practice, research methods, statistics, ethics, resources, and funding. Students were assessed through assignments showing competency in critical literature review, case report writing, and production of a research protocol as the final assessment. Non-student participation for CPD points was possible. A student evaluation survey was completed after the end of the academic year. RESULTS: There were 26 participants: 16 as students handing in assignments, 10 as non-student participants for up to 94 CPD points. Three submitted a final protocol and two registered at a university PhD program. A network of research clinics was established for data collection for future multicenter studies. CONCLUSIONS: The program was well received by the participants and gave them the tools and resources to perform research. The two-level attendance system afforded a basis for setting up a network of research clinics with a fundamental understanding of optimal data collection. This initiative has shown that research skills can be revisited through CPD programs as part of evidence-based lifelong learning.