Altered patterns of displacement within the Achilles tendon following surgical repair.

PURPOSE: Ultrasound speckle tracking was used to compare tendon deformation patterns between uninjured and surgically repaired Achilles tendons at 14-27-month follow-up. The hypothesis was that the non-homogenous displacement pattern previously described in uninjured tendons, where displacement within deep layers of the tendons exceeds that of superficial layers, is altered following tendon rupture and subsequent surgical repair. METHODS: In the first part of this study, an in-house-developed block-matching speckle tracking algorithm was evaluated for assessment of displacement on porcine flexor digitorum tendons. Displacement data from speckle tracking were compared to displacement data from manual tracking. In the second part of the study, eleven patients with previous unilateral surgically treated Achilles tendon rupture were investigated using ultrasound speckle tracking. The difference in superficial and deep tendon displacement was assessed. Displacement patterns in the surgically repaired and uninjured tendons were compared during passive motion (Thompson's squeeze test) and during active ankle dorsiflexion. RESULTS: The difference in peak displacement between superficial and deep layers was significantly (p < 0.01) larger in the uninjured tendons as compared to the surgically repaired tendons both during Thompson's test (-0.7 ± 0.2 mm compared to -0.1 ± 0.1 mm) and active dorsiflexion (3.3 ± 1.1 mm compared to 0.3 ± 0.2 mm). The evaluation of the speckle tracking algorithm showed correlations of r ≥ 0.89 between displacement data acquired from speckle tracking and the reference displacement acquired from manual tracking. Speckle tracking systematically underestimated the magnitude of displacement with coefficients of variation of less than 11.7%. CONCLUSIONS: Uninjured Achilles tendons display a non-uniform displacement pattern thought to reflect gliding between fascicles. This pattern was altered after a mean duration of 19 ± 4 months following surgical repair of the tendon indicating that fascicle sliding is impaired. This may affect modulation of the action between different components of the triceps surae, which in turn may affect force transmission and tendon elasticity resulting in impaired function and risk of re-rupture.

Longitudinal changes in ventral and dorsal neck muscle layers during loading against gravity in healthy volunteers using speckle tracking.

OBJECTIVE: This study aimed to describe and compare the longitudinal mechanical activity, deformation, and deformation rate of the different layers of dorsal and ventral neck muscles in healthy volunteers during head lifts against gravity. METHODS: The cross-sectional study included 19 healthy volunteers (mean age, 28 years; SD, 7 years). Ultrasound with speckle-tracking analysis was used to investigate longitudinal mechanical activation, deformation, and deformation rate of dorsal and ventral neck muscles in real time during a head lift. Significance levels were set as P = .025 or P = .0125, depending on the number of comparisons. RESULTS: The dorsal neck muscles did not significantly differ in deformation (P > .04); however, the multifidus had a higher deformation rate than all other dorsal muscles (P < .003). The sternocleidomastoid had significantly higher deformation than the longus capitis (P = .005) and colli (P = .001) but a lower deformation rate than the longus colli (P = .02). CONCLUSION: The sternocleidomastoid deformed more than the deeper muscles, but it did significantly slower than the longus colli. Among the dorsal muscles, the deepest (the multifidus) had the highest deformation rate.

Cervical muscle activity during loaded arm lifts in patients 10 years postsurgery for cervical disc disease.

OBJECTIVE: The purpose of this study was to compare the mechanical activity of the neck muscles during loaded arm lifting tasks in individuals with long-standing disability after anterior cervical decompression and fusion (ACDF) with that of healthy controls. METHODS: Ten individuals (mean age, 60 years; SD, 7.1) who underwent ACDF (10-13 years previously) for cervical disc disease and 10 healthy age- and sex-matched controls participated in the study. Ultrasonography was used to investigate the degree of deformation and deformation rate of ventral and dorsal neck muscles at the C4 segmental level during a single (1× arm flexion to 120°) and repeated (10× arm flexion to 90°) loaded arm elevation condition. RESULTS: The ACDF group showed greater deformation and deformation rate of the longus capitis (P=.02) and deformation rate of the sternocleidomastoid (P=.04) during the 120° arm lift. For repeated 90° arm lift, there was a significant group effect with higher deformation rate values observed in the longus capitis (P=.005-.01) and multifidus (P=.03) muscles in the ACDF group. Muscle behavior did not change the repeated arm lifts (no group×time interactions) for either the ventral or the dorsal muscles. CONCLUSIONS: For study participants, greater muscle mechanical activity levels were observed in the ventral and multifidus muscles of patients with persistent symptoms after ACDF. These differences may indicate altered motor strategy in this patient group when performing the upper limb task and may need to be considered when prescribing exercise for postsurgical rehabilitation.

Dynamic ultrasound imaging--a multivariate approach for the analysis and comparison of time-dependent musculoskeletal movements.

BACKGROUND: Muscle functions are generally assumed to affect a wide variety of conditions and activities, including pain, ischemic and neurological disorders, exercise and injury. It is therefore very desirable to obtain more information on musculoskeletal contributions to and activity during clinical processes such as the treatment of muscle injuries, post-surgery evaluations, and the monitoring of progressive degeneration in neuromuscular disorders.The spatial image resolution achievable with ultrasound systems has improved tremendously in the last few years and it is nowadays possible to study skeletal muscles in real-time during activity. However, ultrasound imaging has an inherent problem that makes it difficult to compare different measurement series or image sequences from two or more subjects. Due to physiological differences between different subjects, the ultrasound sequences will be visually different - partly because of variation in probe placement and partly because of the difficulty of perfectly reproducing any given movement. METHODS: Ultrasound images of the biceps and calf of a single subject were transformed to achieve congruence and then efficiently compressed and stacked to facilitate analysis using a multivariate method known as O2PLS. O2PLS identifies related and unrelated variation in and between two sets of data such that different phases of the studied movements can be analysed. The methodology was used to study the dynamics of the Achilles tendon and the calf and also the Biceps brachii and upper arm. The movements of these parts of the body are both of interest in clinical orthopaedic research. RESULTS: This study extends the novel method of multivariate analysis of congruent images (MACI) to facilitate comparisons between two series of ultrasound images. This increases its potential range of medical applications and its utility for detecting, visualising and quantifying the dynamics and functions of skeletal muscle. CONCLUSIONS: The most important results of this study are that MACI with O2PLS is able to consistently extract meaningful variability from pairs of ultrasound sequences. The MACI method with O2PLS is a powerful tool with great potential for visualising and comparing dynamics between movements. It has many potential clinical applications in the study of muscle injuries, post-surgery evaluations and evaluations of rehabilitation, and the assessment of athletic training interventions.

Non-uniform displacement within the Achilles tendon during passive ankle joint motion.

PURPOSE: An initial step in the understanding of Achilles tendon dynamics is to investigate the effects of passive motion, thereby minimising muscle activation and reducing internal joint forces. Internal tendon dynamics during passive ankle joint motion have direct implications for clinical rehabilitation protocols after Achilles tendon surgery. The aim of this study was to test the hypothesis that tendon tissue displacement is different in different layers of the Achilles tendon during controlled passive ankle joint movements. METHODS: Ultrasound imaging was conducted on the right Achilles tendon of nine healthy recreationally active males. Standardised isokinetic passive dorsi-plantar-flexion movements were performed with a total range of motion of 35°. The tendon was divided into superficial, central and deep layers in the resulting B-mode ultrasound images viewed in the sagittal plane. A block-matching speckle tracking algorithm was applied post-process, with kernels for the measurement of displacement placed in each of the layers. RESULTS: The mean (SD) displacement of the Achilles tendon during passive dorsiflexion was 8.4 (1.9) mm in the superficial layer, 9.4 (1.9) mm in the central portion and 10.4 (2.1) mm in the deep layer, respectively. In all cases, the movement of the deep layer of the tendon was greater than that of the superficial one (P < 0.01). CONCLUSIONS: These results, achieved in vivo with ultrasonographic speckle tracking, indicated complex dynamic differences in different layers of the Achilles tendon, which could have implications for the understanding of healing processes of tendon pathologies and also of normal tendon function.

Modelling human musculoskeletal functional movements using ultrasound imaging.

BACKGROUND: A widespread and fundamental assumption in the health sciences is that muscle functions are related to a wide variety of conditions, for example pain, ischemic and neurological disorder, exercise and injury. It is therefore highly desirable to study musculoskeletal contributions in clinical applications such as the treatment of muscle injuries, post-surgery evaluations, monitoring of progressive degeneration in neuromuscular disorders, and so on.The spatial image resolution in ultrasound systems has improved tremendously in the last few years and nowadays provides detailed information about tissue characteristics. It is now possible to study skeletal muscles in real-time during activity. METHODS: The ultrasound images are transformed to be congruent and are effectively compressed and stacked in order to be analysed with multivariate techniques. The method is applied to a relevant clinical orthopaedic research field, namely to describe the dynamics in the Achilles tendon and the calf during real-time movements. RESULTS: This study introduces a novel method to medical applications that can be used to examine ultrasound image sequences and to detect, visualise and quantify skeletal muscle dynamics and functions. CONCLUSIONS: This new objective method is a powerful tool to use when visualising tissue activity and dynamics of musculoskeletal ultrasound registrations.

Tissue motion pattern of ventral neck muscles investigated by tissue velocity ultrasonography imaging.

We designed this experimental study to investigate tissue motions and thus infer the recruitment pattern of the ventral neck muscles [sternocleidomastoid (SCM), longus capitis (Lca), and longus colli (Lco)] at the C4-C5 level in healthy volunteers during isometric manual resistance of the head in flexion in a seated position. This exercise is used in the physiotherapeutic treatment of neck pain and is assumed to activate the deep ventral muscles, but the assumption has not been clearly evaluated. Neck flexors of 16 healthy volunteers (mean age 24 years, SD 3.7) were measured using ultrasonography with strain and strain rate (SR) tissue velocity imaging (TVI) during isometric contraction of flexor muscles. TVI involves using Doppler imaging to study tissue dynamics. All three muscles showed a deformation compared to rest. Except for the initial contraction phase, Lco exhibited a lower strain than Lca and SCM but was the only muscle with a significant change in SR between the phases. When the beginning of the contraction phase was analysed, Lco was the first to be deformed among most volunteers, followed by Lca and then SCM. The exercise investigated seems to be useful as a "stabilizing" exercise for Lco. Our suggestion is that in further research, Lco and Lca should be investigated as separate muscles. TVI could be used to study tissue motions and thus serve as an indicator of muscle patterning between the neck flexors, with the possibility of separating Lco and Lca.

Wave intensity wall analysis: a novel noninvasive method to measure wave intensity.

Wave intensity analysis is a concept providing information about the interaction of the heart and the vascular system. Originally, the technique was invasive. Since then new noninvasive methods have been developed. A recently developed ultrasound technique to estimate tissue motion and deformation is speckle-tracking echocardiography. Speckle tracking-based techniques allow for accurate measurement of movement and deformation variables in the arterial wall in both the radial and the longitudinal direction. The aim of this study was to test if speckle tracking-derived deformation data could be used as input for wave intensity calculations. The new concept was to approximate changes of flow and pressure by deformation changes of the arterial wall in longitudinal and radial directions. Flow changes (dU/dt) were approximated by strain rate (sr, 1/s) of the arterial wall in the longitudinal direction, whereas pressure changes (dP/dt) were approximated by sign reversed strain rate (1/s) in the arterial wall in the radial direction. To validate the new concept, a comparison between the newly developed Wave Intensity Wall Analysis (WIWA) algorithm and a commonly used and validated wave intensity system (SSD-5500, Aloka, Tokyo, Japan) was performed. The studied population consisted of ten healthy individuals (three women, seven men) and ten patients (all men) with coronary artery disease. The present validation study indicates that the mechanical properties of the arterial wall, as measured by a speckle tracking-based technique are a possible input for wave intensity calculations. The study demonstrates good visual agreement between the two systems and the time interval between the two positive peaks (W1-W2) measured by the Aloka system and the WIWA system correlated for the total group (r = 0.595, P < 0.001). The correlation for the diseased subgroup was r = 0.797, P < 0.001 and for the healthy subgroup no significant correlation was found (P > 0.05). The results of the study indicate that the mechanical properties of the arterial wall could be used as input for wave intensity calculations. The WIWA concept is a promising new method that potentially provides several advantages over earlier wave intensity methods, but it still has limitations and needs further refinement and larger studies to find the optimal clinical use.

The complex interplay between pain intensity, depression, anxiety and catastrophising with respect to quality of life and disability.

PURPOSE: To identify subgroups of patients with chronic pain based on the occurrence of depression, anxiety and catastrophising and the duration of pain and pain intensity. In addition to this, the relationship between the subgroups with respect to background variables, diagnosis, pain-related disability and perceived quality of life are investigated. METHODS: This study used 433 patients with chronic pain including 47 patients with spinal cord injury-related pain, 150 with chronic whiplash associated disorders and 236 with fibromyalgia. The participants answered a postal questionnaire that provided background data, pain intensity and duration and psychological and health-related items. RESULTS: On the basis of depression, anxiety, catastrophising, pain intensity and duration, we identified subgroups of patients with chronic pain that differed with respect to perceived quality of life, disability and diagnosis. The psychological factors, especially depression, significantly influenced perceived quality of life and disability. Pain intensity and duration play a minor role with respect to quality of life, although pain intensity is associated to perceived disability. CONCLUSIONS: The results of this study highlight the importance of not looking at patients with chronic pain as a homogenous entity. A detailed assessment, including psychological factors with emphasis on depressive symptoms, might be essential for planning and carrying through treatment and rehabilitation.

Predictive factors for long-term outcome of anterior cervical decompression and fusion: a multivariate data analysis.

We conducted a prospective randomized study to investigate predictive factors for short- and long-term outcome of anterior cervical decompression and fusion (ACDF) as measured by current pain intensity on the Visual Analogue Scale (VAS) and by disability using the Neck Disability Index (NDI). Current understanding about how preoperative and short-term outcome data predict long-term outcome is sparse, and there are few studies involving analysis of short-term follow-up using multivariate approaches with quantification of the relative importance of each variable studied. A total of 95 patients were randomly allocated for ACDF with the cervical intervertebral fusion cage or the Cloward procedure. The mean follow-up time was 19 months (range 12-24) for short-term follow-up and 76 months (range 56-94 months) for long-term. Background factors, radiologically detected findings, physiological measurements, treatment type, pain, and disability were used as potential predictors. Multivariate statistical analysis by projection to latent structures was used to investigate predictors of importance for short- and long-term outcome of ACDF. A "preoperative" low disability and pain intensity, non-smoking status, male sex, good hand strength, and an active range of motion (AROM) in the neck were significant predictors for good short- and long-term outcomes. The short-term outcome data were better at predicting long-term outcome than were baseline data. Radiologically detected findings and surgical technique used were mainly insignificant as predictors. We suggest that the inclusion criteria for ACDF should be based on a bio-psycho-social model including NDI. NDI may also be regarded as an important outcome measurement in evaluation of ACDF.

Catastrophizing, depression, and pain: correlation with and influence on quality of life and health - a study of chronic whiplash-associated disorders.

OBJECTIVE: The aims of this study were: (i) to classify subgroups according to the degree of pain intensity, depression, and catastrophizing, and investigate distribution in a group of patients with chronic whiplash-associated disorders; and (ii) to investigate how these subgroups were distributed and inter-related multivariately with respect to consequences such as health and quality of life outcome measures. DESIGN: Descriptive cross-sectional study. PATIENTS: A total of 275 consecutive chronic pain patients with whiplash-associated disorders who were referred to a university hospital. METHODS: The following data were obtained by means of self-report questionnaires: pain intensity in neck and shoulders, background history, Beck Depression Inventory, the catastrophizing scale of Coping Strategy Questionnaire, Life Satisfaction Checklist, the SF-36 Health Survey, and the EuroQol. RESULTS: Principal component analysis was used to recognize subgroups according to the degree of pain intensity, depression, and catastrophizing. These subgroups have specific characteristics according to perceived health and quality of life, and the degree of depression appears to be the most important influencing factor. CONCLUSION: From a clinical point of view, these findings indicate that it is important to assess patients for intensity of pain, depression, and catastrophizing when planning a rehabilitation programme. Such an evaluation will help individualize therapy and intervention techniques so as to optimize the efficiency of the programme.

A pilot study using Tissue Velocity Ultrasound Imaging (TVI) to assess muscle activity pattern in patients with chronic trapezius myalgia.

BACKGROUND: Different research techniques indicate alterations in muscle tissue and in neuromuscular control of aching muscles in patients with chronic localized pain. Ultrasound can be used for analysis of muscle tissue dynamics in clinical practice. AIM: This study introduces a new muscle tissue sensitive ultrasound technique in order to provide a new methodology for providing a description of local muscle changes. This method is applied to investigate trapezius muscle tissue response - especially with respect to specific regional deformation and deformation rates - during concentric shoulder elevation in patients with chronic trapezius myalgia and healthy controls before and after pain provocation. METHODS: Patients with trapezius myalgia and healthy controls were analyzed using an ultrasound system equipped with tissue velocity imaging (TVI). The patients performed a standardized 3-cm concentric shoulder elevation before and after pain provocation/exercise at a standardized elevation tempo (30 bpm). A standardized region of interest (ROI), an ellipsis with a size that captures the upper and lower fascia of the trapezius muscle (4 cm width) at rest, was placed in the first frame of the loop registration of the elevation. The ROI was re-anchored frame by frame following the same anatomical landmark in the basal fascia during all frames of the concentric phase. In cardiac measurement, tissue velocities are measured in the axial projection towards and against the probe where red colour represents shortening and red lengthening. In the case of measuring the trapezius muscle, tissue deformation measurements are made orthogonally, thus, indirectly. Based on the assumption of muscle volume incompressibility, blue represents tissue contraction and red relaxation. Within the ROI, two variables were calculated as a function of time: deformation and deformation rate. Hereafter, max, mean, and quadratic mean values (RMS) of each variable were calculated and compared before and after pain provocation/exercise. RESULTS: This new methodology seems valuable when looking at local muscle changes and studying the mechanism behind chronic muscle pain. The univariate analyses indicate that patients with chronic trapezius myalgia after pain provocation due to exercise at group level showed decreased strain and unchanged strain rate while healthy controls had unchanged strain and increased strain rate. However, the multivariate analysis indicates that most patients showed lower levels according to both strain and strain rate after exercise compared to most controls. CONCLUSION: Tissue velocity imaging can help describe musculoskeletal tissue activity and dynamics in patients with chronic pain conditions. An altered muscle tissue dynamic after pain provocation/exercise among the majority of trapezius myalgia patients compared with the healthy controls was found.

Multivariate relationships between pain intensity and other aspects of health in rheumatoid arthritis--cross sectional and five year longitudinal analyses (the Swedish TIRA project).

OBJECTIVES: This study analyses the relationships between pain intensity and other aspects of health commonly used to assess disease activity and disability in early rheumatoid arthritis and examines whether such relationships were different between women and men. SUBJECTS AND METHODS: This study included the 189 patients (69% women) with early RA (symptoms <12 months at diagnosis) still remaining in the Swedish TIRA cohort 5 years after inclusion. Disease activity and disability was assessed 3, 6, 12, 18, 24, 36, 48, and 60 months (M0-M60) after inclusion by erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), number of swollen and tender joints, physicians global assessment of disease activity (PGA), grip force average over 10 seconds (Grippit), Grip Ability Test (GAT), Signals of Functional Impairment (SOFI) in hand, lower limb and upper limb, Health Assessment Questionnaire (HAQ), and pain intensity measured with a visual analogue scale (VAS). The variables were divided into meaningful blocks according to the correlation structure in a principal component analysis (PCA) at M60. Using hierarchical partial least squares (PLS) analyses, this study investigated the blocks cross-sectionally to test for correlations with pain intensity at M0 and M60. The blocks at M0 were also used as predictors of pain intensity at M60 in a hierarchical PLS. RESULTS: The strongest relationship was found between pain intensity and the second block, consisting of HAQ and SOFI-lower limb at the cross-sectional analyses in both women and men. The block representing disease activity (i.e., ESR, CRP, PGA, and swollen and tender joints) had the weakest relation to pain intensity. According to the longitudinal analyses, the disease activity variables (block 1) at M0 had the strongest relationship to pain intensity at M60 in men. In contrast, HAQ and SOFI-lower limb (block 2) at M0 had a strong relation to pain intensity in women.

Generalized pain is associated with more negative consequences than local or regional pain: a study of chronic whiplash-associated disorders.

OBJECTIVE: The main aims of this study were: (i) to determine, for chronic whiplash-associated disorders, whether widespread pain has more severe consequences for other symptoms and different aspects of perceived health than does local/regional pain; (ii) to investigate whether pain, depression, and symptoms not directly related to pain are intercorrelated and to what extent these symptoms correlate with catastrophizing according to the Coping Strategy Questionnaire. DESIGN: Descriptive cross-sectional study. PATIENTS: A total of 275 consecutive chronic pain patients with whiplash-associated disorders who were referred to a university hospital. METHODS: Background history, Beck Depression Inventory, Coping Strategy Questionnaire, Life Satisfaction Checklist, the SF-36 Health Survey and EuroQol were used to collect data. RESULTS: Spreading of pain was associated with negative consequences with respect to pain intensity and prevalence of other symptoms, life satisfaction/quality and general health. The subjects differ with respect to the presence of symptoms not directly related to pain. A minor part of the variation in Back Depression Inventory was explained by direct aspects of pain, indicating that, to some extent, generalization of pain is related to catastrophizing thoughts. CONCLUSION: Widespread pain was associated with negative consequences with respect to pain intensity, prevalence of other symptoms including depressive symptoms, some aspects of coping, life satisfaction and general health.

Increased levels of interstitial potassium but normal levels of muscle IL-6 and LDH in patients with trapezius myalgia.

The mechanisms behind the development of work-related trapezius pain are suggested to involve both peripheral and central components, but the specific contribution of alterations in muscle nociceptive and other substances is not clear. Female patients with chronic trapezius myalgia (N=19; TM) and female controls (N=20; CON) were studied at rest, during 20 min repetitive low-force exercise and recovery, and had their interstitial concentrations of potassium (K(+)), lactate dehydrogenase (LDH), interleukin-6 (IL-6) and collagen turnover determined in the trapezius muscle by the microdialysis technique. K(+) levels were at all time points higher in TM than in CON (P<0.0001). Baseline levels of LDH and IL-6 were similar in both groups. In response to exercise pain intensity, rated perceived exertion, and the concentrations of K(+), LDH and IL-6 increased significantly in both groups. [K(+)] immediately decreased to baseline levels in CON but remained elevated during the first 20 min of recovery in TM (P<0.01) whereafter it returned to baseline level. In all subjects taken together mean [K(+)] correlated negatively with pressure pain threshold of trapezius (P<0.001), positively with mean pain intensity VAS (P<0.001) and mean perceived exertion (P<0.001). Rises in muscle LDH and IL-6 as well as the anabolic ratio for collagen type I was not significantly different between groups. In conclusion, patients with chronic pain in the trapezius muscle had increased levels of interstitial potassium. This finding could be causally related to myalgia or secondary to pain due to deconditioned muscle or altered muscle activity pattern.

Altered ventral neck muscle deformation for individuals with whiplash associated disorder compared to healthy controls - a case-control ultrasound study.

Previous studies have shown altered neck muscle function in individuals with chronic whiplash associated disorder (WAD). However, we lack real-time investigations with non-invasive methods that can distinguish between the different ventral neck muscle layers. This study investigated deformations and deformation rates in the sternocleidomastoid (SCM), longus capitis (Lcap), and longus colli (Lco) muscles with real-time ultrasonography. Twenty-six individuals with WAD were compared with 26 controls, matched for age and sex. Ultrasound imaging of the SCM, Lcap, and Lco were recorded during 10 repetitive arm elevations. The first and tenth arm elevations were post-process analyzed with speckle tracking. There were few significant differences in the deformations or deformation rates in the SCM, Lcap, and Lco between the WAD and control group. In controls, deformations and deformation rates showed linear positive relationships between SCM/Lcap, SCM/Lco, and Lcap/Lco which increased from the first arm elevation (R(2) = 0.14-0.70); to the tenth arm elevation (R(2) = 0.51-0.71). The WAD group showed similar or weaker linear relationship (R(2) < 0.19) during the tenth compared to the first (R(2) < 0.44) arm elevation except for deformations in Lcap/Lco (R(2) = 0.13-0.57). This result indicated that deformations and deformation rates in one muscle were correlated by similar deformations and deformation rates in other neck muscles in the control group, but this interplay between muscles was not found in the WAD group.

Increase in muscle nociceptive substances and anaerobic metabolism in patients with trapezius myalgia: microdialysis in rest and during exercise.

Local metabolic changes are suggested to be involved in muscle pain development in humans. Nineteen women with chronic work-related trapezius myalgia (TM) and 20 healthy female controls (CON) were studied during baseline rest, 20 min repetitive low-force exercise, and 120 min recovery. Interstitial serotonin (5-HT), glutamate, lactate, pyruvate, and blood flow were determined by microdialysis in the trapezius muscle. Baseline pressure pain threshold (PPT) was lower (143+/-18 (TM) vs. 269+/-17 (CON)kPa) (mean+/-SEM), pain intensity (visual analogue scale, VAS) higher (33+/-5 vs. 2+/-1mm), muscle 5-HT higher (22.9+/-6.7 vs. 3.8+/-1.3 nmol/l), and glutamate higher (47+/-3 vs. 36+/-4 micromol/l) in TM than in CON (all P<0.05), whereas muscle blood flow was similar in groups. Furthermore, muscle pyruvate was higher (180+/-15 vs. 135+/-12 micromol/l) and lactate higher (4.4+/-0.3 vs. 3.1+/-0.3 mmol/l) in TM than in CON (P<0.001). In response to exercise, VAS and glutamate increased in both TM and CON (all P<0.05). In TM only, lactate and pyruvate increased significantly (P<0.02), whereas blood flow increased to similar levels in both groups. During the initial 20 min recovery period, blood flow remained increased in TM (P<0.005) whereas it decreased to baseline levels in CON. In conclusion, patients with chronic work-related TM have increased levels of muscle 5-HT and glutamate that were correlated to pain intensity (r=0.55, P<0.001) and PPT (r=-0.47, P<0.001), respectively. In addition, TM was associated with increased anaerobic metabolism, whereas a normal rise in blood flow was seen with exercise. These findings indicate that peripheral nociceptive processes are active in work-related TM.

Coping in patients with chronic whiplash-associated disorders: a descriptive study.

OBJECTIVE: There are few studies of the way patients with chronic whiplash-associated disorders cope with pain and other aspects of the condition. This study analyses: (a) gender differences in coping strategies; (b) whether the patients can be sub-grouped based on their coping strategies and whether the sub-groups differ clinically; and (c) the relative importance of background variables, symptoms and coping for quality of life. DESIGN: A descriptive study. PATIENTS: A total of 275 consecutive chronic patients with whiplash-associated disorders referred to a university hospital. METHODS: A questionnaire covering background data, pain in different regions, symptoms not directly related to pain, Beck depression inventory, a Coping Strategy Questionnaire, a Life Satisfaction checklist (LiSat-11), SF-36 Health Survey and EuroQol instrument. RESULTS: Three groups of patients were identified with respect to coping. Whether or not active coping strategies were used had little influence on health-related quality of life. When regressing health-related quality of life items, the following regressors were the most important: degree of depression, number of not directly pain-related symptoms, and catastrophizing cognitions influenced by pain intensities. CONCLUSION: A mixture of symptoms (pain and depression) and coping (catastrophizing) seem to be interwoven and explain patients' health-related quality of life. These characteristics should be assessed when planning rehabilitation.

A speckle tracking application of ultrasound to evaluate activity of multilayered cervical muscles.

OBJECTIVE: To evaluate the capacity of the ultrasound-based method of speckle tracking analysis to detect changes in multilayered dorsal neck muscle activity induced by performing a lifting task. SUBJECTS: Twenty-one healthy individuals. DESIGN: Participants performed a loaded lifting task in 3 different postural orientations of the neck (neutral, flexed and forward head posture). Ultrasound images were recorded and speckle tracking analysis was used to quantify muscle deformation and deformation rate over 3 equal time-periods during the lifting sequence (rest, mid-lift and end-lift). RESULTS: Significant main effects of postural orientation for the deformation measure (p < 0.05) and time for the deformation rate measure (p < 0.05) were observed in all dorsal muscles examined. Significant time by postural interactions for the deformation measure were observed in the trapezius, semispinalis cervicis and multifidus (p < 0.05) and in the semispinalis cervicis (p < 0.05) for the deformation rate measure. CONCLUSION: Speckle tracking analysis ultrasound measurements can detect differences in multilayered muscle activity of the dorsal neck induced by postural variations during a lifting task. Findings for the deformation and the deformation rate measures suggest that they quantify a different, albeit related, mechanical event during muscle contraction in a functional task such as lifting.

Does posture of the cervical spine influence dorsal neck muscle activity when lifting?

Previous studies have shown that postural orientations of the neck, such as flexed or forward head postures, are associated with heightened activity of the dorsal neck muscles. While these studies describe the impact of variations in neck posture alone, there is scant literature regarding the effect of neck posture on muscle activity when combined with upper limb activities such as lifting. The purpose of this study was to evaluate the effect of three different neck postures on the activity of the different layers of the dorsal neck muscles during a lifting task. Ultrasound measurements of dorsal neck muscle deformation were compared over two time points (rest, during lift) during a lifting task performed in three different neck postural conditions (neutral, flexed and forward head posture) in 21 healthy subjects. Data were analysed by post-process speckle tracking analysis. Results demonstrated significantly greater muscle deformation induced by flexed and forward head postures, compared to the neutral posture, for all dorsal neck muscles at rest (p<0.05). Significant condition by time interactions associated with the lift was observed for four out of the five dorsal muscles (p<0.02). These findings demonstrate that posture of the cervical spine influenced the level of muscle deformation not only at rest, but also when lifting. The findings of the study suggest that neck posture should be considered during the evaluation or design of lifting activities as it may contribute to excessive demands on dorsal neck muscles with potential detrimental consequences.