Chronic pain after soft-tissue injury of the cervical spine: trapezius muscle blood flow and electromyography at static loads and fatigue

Department of Orthopaedics, University Hospital, Linköping, Sweden.
Pain (Impact Factor: 5.21). 06/1994; 57(2):173-80. DOI: 10.1016/0304-3959(94)90221-6
Source: PubMed


Microcirculation in the upper portion of the right and left trapezius muscles was measured percutaneously by laser-doppler flowmetry (LDF) during two 10-min-long series of alternating 1-min periods of static contraction and rest determined electromyographically (EMG). Twenty-five patients with pain persisting after a soft-tissue injury of the neck were studied. Pain assessments by using visual analogue scales and drawings showed 13 patients with predominantly unilateral and 12 with bilateral neck-shoulder pain, in some cases with arm pain and numbness. Mean age was 41 (23-58) and 39 (22-54) years and a female/male ratio 8:5 and 10:2, respectively. Stepwise increased contraction was induced by keeping straight arms at 30 degrees, 60 degrees, 90 degrees and 135 degrees of elevation, and repeated with a 1 kg (women) or 2 kg (men) hand loads. Signal processing was done on-line by using a 386SX computer. LDF and EMG values were normalized. Spectral shift of EMG mean power frequency (MPF) for fatigue was analyzed. Muscle blood flow on the "normal" side in the unilateral pain group showed an ordinary increase at increased angle of arm elevation, shoulder torque and EMG amplitude. On the painful side, during increased muscle tension and fatigue, the ability to increase blood flow appeared to be impaired, and there was no consistent increase in either side of the bilateral pain group. EMG amplitude showed a significant positive correlation to the angle of arm elevation and shoulder torque. The rms-EMG (root mean squared EMG) increase was lower in the painful side at high force contraction (non-normalized data).(ABSTRACT TRUNCATED AT 250 WORDS)

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    • "To examine this issue, quantitative measurements of enzyme activity in single fibres are essential. A proposed mechanism underlying the assumed deficiency in mitochondrial potential is cellular hypoperfusion (Larsson et al. 1994, 1999; Brunnekreef et al. 2006), occurring as a result of a low capillary to fibre area ratio (CC/Area) and mediated by type-1 fibres with an abnormally large cross sectional area (Area) (Larsson et al. 2007) and (or) an inadequate number of capillaries (Larsson et al. 2004). The former could be a result of hypertrophy, possibly occurring in only a subgroup of type-I fibres (Andersen et al. 2008), or as a result of transition to a greater abundance of type-I fibres with large areas (Kadi et al. 1998b). "
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    ABSTRACT: To investigate fibre-type abnormalities in women with work-related myalgia (WRM), tissue samples were extracted from their trapezius (TRAP) and the extensor carpi radialis brevis (ECRB) muscles and compared with healthy controls (CON). For the ECRB samples (CON, n = 6; WRM, n = 11), no differences (P > 0.05) were found between groups for any of the properties examined, namely fibre-type (I, IIA, IIX, IIAX) distribution, cross-sectional fibre area, capillary counts (CC), capillary to fibre area ratio, and succinic dehydrogenase activity. For the TRAP samples (CON, n = 6; WRM, n = 8), the only difference (P < 0.05) observed between groups was for CC (CON > WRM), which was not statistically significant (P > 0.05) when age was used a covariant. A comparison of the properties of these 2 muscles in the CON group indicated a higher (P < 0.05) and lower (P < 0.05) percentage of type I and type IIA fibres, respectively, in the TRAP as well as higher (P < 0.05) CC, which was not specific to fibre type. These preliminary results suggest that the properties employed to characterize fibre types do not differentiate CON from WRM for either the TRAP or ECRB. As a consequence, the role of inherent fibre-type differences between these muscles in the pathogenesis of WRM remains uncertain.
    Canadian Journal of Physiology and Pharmacology 04/2014; 92(4):315-23. DOI:10.1139/cjpp-2013-0301 · 1.77 Impact Factor
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    • "Structural MRI studies indicate that WAD patients have high fatty infiltration in the cervical muscles [13], and an autopsy study suggest an increase in type IIC muscle fibers in the neck flexor muscles of patients with chronic neck pain [14]. Also, impairments in intramuscular microcirculation have been demonstrated in painful muscles [15]. Along with inflammation, these alterations in the microstructure and tissue composition of cervical tissue in WAD patients are possible mechanisms which could lead to elevated [11C]D-deprenyl retention. "
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    ABSTRACT: There are few diagnostic tools for chronic musculoskeletal pain as structural imaging methods seldom reveal pathological alterations. This is especially true for Whiplash Associated Disorder, for which physical signs of persistent injuries to the neck have yet to be established. Here, we sought to visualize inflammatory processes in the neck region by means Positron Emission Tomography using the tracer (11)C-D-deprenyl, a potential marker for inflammation. Twenty-two patients with enduring pain after a rear impact car accident (Whiplash Associated Disorder grade II) and 14 healthy controls were investigated. Patients displayed significantly elevated tracer uptake in the neck, particularly in regions around the spineous process of the second cervical vertebra. This suggests that whiplash patients have signs of local persistent peripheral tissue inflammation, which may potentially serve as a diagnostic biomarker. The present investigation demonstrates that painful processes in the periphery can be objectively visualized and quantified with PET and that (11)C-D-deprenyl is a promising tracer for these purposes.
    PLoS ONE 04/2011; 6(4):e19182. DOI:10.1371/journal.pone.0019182 · 3.23 Impact Factor
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    • "As a sizeable proportion of whiplash injured patients go on to develop longstanding symptoms, WAD constitutes a significant socioeconomic burden, with the annual cost to the UK economy estimated at around £3.1 billion (with health service and social security costs, damage to property, and lost productivity taken into account) (Galasko et al., 2002). Nonetheless, the aetiology of whiplash derived pain remains unclear, primarily because signs of soft tissue damage (via laboratory tests or radiological imaging) are rare (Larsson et al., 1994). There are claims, however, from experts in clinical practice that myofascial trigger points (MTrPs), described as e 'tender points located in taut bands of skeletal muscle, which on palpation reproduce the patient's pain' (Simons et al., 1999) e are a primary source of pain following whiplash injury (Evans, 1992; Fricton, 1993; Dommerholt, 1997; Gerwin and Dommerholt, 1998). "
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    ABSTRACT: Clinicians claim that myofascial trigger points (MTrPs) are a primary cause of pain in whiplash injured patients. Pain from MTrPs is often treated by needling, with or without injection. We conducted a placebo controlled study to test the feasibility of a phase III randomised controlled trial investigating the efficacy of MTrP needling in patients with whiplash associated pain. Forty-one patients referred for physiotherapy with a recent whiplash injury, were recruited. Patients were randomised to receive standardised physiotherapy plus either acupuncture or a sham needle control. A trial was judged feasible if: i) the majority of eligible patients were willing to participate; ii) the majority of patients had MTrPs; iii) at least 75% of patients provided completed self-assessment data; iv) no serious adverse events were reported and v) the end of treatment attrition rate was less than 20%. 70% of those patients eligible to participate volunteered to do so; all participants had clinically identified MTrPs; a 100% completion rate was achieved for recorded self-assessment data; no serious adverse events were reported as a result of either intervention; and the end of treatment attrition rate was 17%. A phase III study is both feasible and clinically relevant. This study is currently being planned.
    Manual therapy 12/2010; 15(6):529-35. DOI:10.1016/j.math.2010.05.010 · 1.71 Impact Factor
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