Surgeons' posture and muscle strain during laparoscopic and robotic surgery.

BACKGROUND: It is assumed that conventional laparoscopy (LAP) and robotic-assisted laparoscopic surgery (RALS) differ in terms of the surgeon's comfort. This study compared muscle workload, work posture and perceived physical exertion of surgeons performing LAP or RALS. METHODS: Colorectal surgeons with experience in advanced LAP and RALS performed one of each operation. Bipolar surface electromyography (EMG) recordings were made from forearm, shoulder and neck muscles, and expressed relative to EMG maximum (%EMGmax ). The static, median and peak levels of muscle activity were calculated, and an exposure variation analysis undertaken. Postural observations were carried out every 10 min, and ratings of perceived physical exertion before and after surgery were recorded. RESULTS: The study included 13 surgeons. Surgeons performing LAP showed higher static, median, and peak forearm muscle activity than those undertaking RALS. Muscle activity at peak level was higher during RALS than LAP. Exposure variation analysis demonstrated long-lasting periods of low-level intensity muscle activity in the shoulders for LAP, in the forearms for RALS, and in the neck for both procedures. Postural observations revealed a greater need for a change in work posture when performing LAP compared with RALS. Perceived physical exertion was no different between the surgical modalities. CONCLUSION: Minimally invasive surgery requires long-term static muscle activity with a high physical workload for surgeons. RALS is less demanding on posture.

ANTECEDENTES: Se asume que la cirugía laparoscópica (laparoscopic, LAP) y la cirugía laparoscópica asistida por robot (robotic-assisted laparoscopic surgery, RALS) difieren en cuanto a la comodidad del cirujano. En este estudio se comparó la carga de trabajo muscular, la postura de trabajo y el esfuerzo físico percibido por los cirujanos al realizar LAP o RALS. MÉTODOS: Trece cirujanos colorrectales con experiencia en LAP avanzada y RALS realizaron una operación con cada uno de los abordajes. Se registró la electromiografía de superficie bipolar en los músculos del antebrazo, del hombro y del cuello, y se expresó en relación con el EMG máximo (% EMGmax). Se calculó el nivel de actividad muscular estático, mediano y pico, y se realizó un análisis de variación de la exposición. Las observaciones posturales se llevaron a cabo cada diez minutos y se registraron las valoraciones del esfuerzo físico percibido antes y después de la cirugía. RESULTADOS: La práctica de LAP mostró una mayor actividad muscular estática, mediana y pico del antebrazo en comparación con la práctica de RALS. El hombro izquierdo mostró la mayor actividad muscular en RALS a nivel máximo. El análisis de variación de exposición demostró periodos prolongados de actividad muscular de baja intensidad para LAP en los hombros, para RALS en los antebrazos y para ambos en el cuello. Las observaciones posturales mostraron una mayor necesidad de un cambio en la postura de trabajo al realizar LAP en comparación con RALS. El esfuerzo físico percibido no fue diferente entre ambas modalidades quirúrgicas. CONCLUSIÓN: La cirugía mínimamente invasiva requiere una actividad muscular estática prolongada con una alta carga de trabajo físico para los cirujanos. RALS es menos exigente en el aspecto postural.

Pneumonia and the incidence of cancer: a Danish nationwide cohort study.

OBJECTIVES: To examine the risk of a subsequent pulmonary or extra-pulmonary cancer diagnosis following a first-time hospital-based diagnosis of pneumonia. DESIGN: Population-based cohort study using Danish medical registries. SETTING: All hospitals in Denmark. SUBJECTS: A total of 342,609 patients with a first-time hospital-based (inpatient, emergency room or outpatient clinic) diagnosis of pneumonia between 1995 and 2011. MAIN OUTCOME MEASURES: We quantified the excess risk of various cancers amongst pneumonia patients compared to the expected risk in the general population, using relative [standardised incidence ratios (SIRs)] and absolute risk calculations. Follow-up started 1 month after a hospital-based diagnosis of pneumonia and ended on 31 December 2011. RESULTS: A total of 28,496 cancers were observed, compared with 21,625 expected, amongst 342,609 pneumonia patients followed for a median of 4.2 years. The absolute risk of a cancer diagnosis 1 to <6 months following a pneumonia diagnosis was 1.4%, with a corresponding SIR of 2.48 [95% confidence interval (CI) 2.41-2.55]. This was mainly due to an increased risk of lung cancer (eightfold) and haematological cancers (fourfold). The SIR for any cancer remained increased at 1.35 (95% CI 1.30-1.40) during 6-12 months of follow-up, and 1.20 (95% CI 1.18-1.22) during 1-5 years of follow-up. Beyond 5 years, an increased risk was maintained for lung, oesophageal, liver and bladder cancers, squamous cell carcinoma of the skin, lymphoma and multiple myeloma. CONCLUSIONS: A hospital-based pneumonia diagnosis was associated with an increased risk of a cancer diagnosis, especially in the ensuing months, but the absolute risk was small.

Properties of the Tampa Scale for Kinesiophobia across Workers with Different Pain Experiences and Cultural Backgrounds: A Rasch Analysis.

The main aim of this study was to evaluate whether the construct validity of the Tampa Scale for Kinesiophobia (TSK) is consistent with respect to its scaling properties, unidimensionality and targeting among workers with different levels of pain. The 311 participating Danish workers reported kinesiophobia by TSK (13 statement version) and number of days with pain during the past year (less than 8 days, less than 90 days and greater than 90 days). A Rasch analysis was used to evaluate the measurement properties of the TSK in the workers across pain levels, ages, genders and ethnicities. The TSK did not fit the Rasch model, but removing one item solved the poorness of fit. Invariance was found across the pain levels, ages and genders. Thus, with a few modifications, the TSK was shown to capture a unidimensional construct of fear of movement in workers with different pain levels, ages, and genders.

Comparison of objectively measured and self-reported time spent sitting.

Until recently, methods for objective quantification of sitting time have been lacking. The aim of this study was to validate self-reported measures against objectively measured total sitting time and longest continuous time with uninterrupted sitting during working hours, leisure time on workdays and leisuredays. Objective diurnal measurement of sitting time was obtained among 26 office workers with 2 accelerometers (ActiGraph GT3X+) for a 7-day period. Customized software (Acti4) was used to identify sitting time separated from other sedentary behaviours. Self-reported sitting time was obtained from a retrospective 7-day questionnaire. A generalized linear model showed the difference between the methods. No significant correlations were found between objective and self-reported sitting time (r<0.315). Total sitting time was significantly underestimated (2.4 h) on a leisureday (p<0.001) and uninterrupted sitting time was in all 3 time settings significantly overestimated (0.4-0.5 h) (p<0.045). Poor agreement (mean difference between 0.5 to -2.4 h) between objectively measured and self-reported sitting time was shown in Bland-Altman plots with wide (3.3-10.8 h) limits of agreement. This study showed a great individual variation and a general lack of agreement between self-reported vs. objectively measured total and uninterrupted sitting time. Objective measures are recommended for determining sitting time.

The interactions between pain, pain-related fear of movement and productivity.

BACKGROUND: Employees with physically heavy work have an increased risk of musculoskeletal disorders leading to reduced work ability. AIMS: To investigate if a high level of musculoskeletal pain or pain-related fear of movement was associated with low productivity among employees with physically heavy work and differing work ability levels. METHODS: The study was conducted at a Danish production site and employees with physically heavy work in the production line were included in the study. Work ability was assessed with the Work Ability Index (WAI), pain-related fear of movement with the Tampa Scale for Kinesiophobia and productivity and musculoskeletal pain by self-reported measures. Sickness absence records for construction of WAI were obtained from the workplace. RESULTS: There was a 77% response rate with 350 employees included in the final analysis. Among employees with only moderate work ability, there was neither an association between pain and productivity nor between pain-related fear of movement and productivity. For employees with good work ability, higher levels of pain and higher levels of pain-related fear of movement both raised the odds of low productivity significantly. CONCLUSIONS: Despite the fact that musculoskeletal pain increases the risk of reduced work ability significantly, musculoskeletal pain and pain-related fear of movement were associated with low productivity only among employees with good work ability.

The health paradox of occupational and leisure-time physical activity.

BACKGROUND: Occupational and leisure-time physical activity are considered to provide similar health benefits. The authors tested this hypothesis. METHODS: A representative sample of Danish employees (n=7144, 52% females) reported levels of occupational and leisure-time physical activity in 2005. Long-term sickness absence (LTSA) spells of ≥3 consecutive weeks were retrieved from a social-transfer payment register from 2005 to 2007. RESULTS: 341 men and 620 females experienced a spell of LTSA during the period. Cox analyses adjusted for age, gender, smoking, alcohol, body mass index, chronic disease, social support from immediate superior, emotional demands, social class and occupational or leisure-time physical activity showed a decreased risk for LTSA among workers with moderate (HR 0.85, CI 0.72 to 1.01) and high (HR 0.77, CI 0.62 to 0.95) leisure-time physical activity in reference to those with low leisure-time physical activity. In contrast, an increased risk for LTSA was shown among workers with moderate (HR 1.59, CI 1.35 to 1.88) and high (HR 1.84, CI 1.55 to 2.18) occupational physical activity referencing those with low occupational physical activity. CONCLUSION: The hypothesis was rejected. In a dose-response manner, occupational physical activity increased the risk for LTSA, while leisure-time physical activity decreased the risk for LTSA. The findings indicate opposing effects of occupational and leisure-time physical activity on global health.

Does muscle strength predict future musculoskeletal disorders and sickness absence?

BACKGROUND: High muscle strength is considered relevant for preventing musculoskeletal disorders and long-term sickness absence. However, prospective studies on the association between muscle strength and future musculoskeletal disorders and long-term sickness absence are few and show contrasting results. AIMS: To investigate the association between low muscle strength and future musculoskeletal disorders and long-term sickness absence. METHODS: Muscle strength in trunk flexion and extension, shoulder elevation and abduction as well as handgrip was recorded from a representative sample of Danish workers (n = 421) in 1995. Musculoskeletal disorders were reported 5 years later (in 2000). Information on long-term sickness absence was retrieved from a register of social transfer payments in the period 1996-2007. RESULTS: Regression analyses adjusted for age, gender, smoking, body mass index and physical work demands showed that workers with low muscle strength (the lowest quartile) of trunk extension and flexion, shoulder elevation and abduction and handgrip did not have a significantly increased risk for future musculoskeletal disorders or long term sickness absence compared with stronger workers. CONCLUSIONS: Low muscle strength does not seem to be a good predictor for musculoskeletal disorders and long-term sickness absence in the general working population.

What characterizes cleaners sustaining good musculoskeletal health after years with physically heavy work?

OBJECTIVES: The aim of this case-control study was to investigate characteristics of cleaners with good musculoskeletal health after years with physically heavy work. METHODS: One hundred and 41 female seniority cleaners participated. Twenty-five reported no musculoskeletal symptoms, whereas 83 reported severe symptoms in the low back, neck shoulders or upper limbs. The groups were of matching age, height, body weight and seniority (19 years). Muscular strength was recorded by isometric maximal voluntary contractions on a day without pain. Exposure to physical risk factors at work, psychosocial work factors, and leisure time physical activity were assessed by a postal questionnaire. RESULTS: Cleaners with good musculoskeletal health were not reporting different exposure to physical risk factors at work or leisure time physical activity, but had higher muscular strength and reported higher influence at work than cleaners with severe symptoms. CONCLUSIONS: These findings suggest that muscular strength and influence at work are of relevance for sustaining good musculoskeletal health in workers with physically heavy work.

Work related perceived stress and muscle activity during standardized computer work among female computer users.

The current study investigated the associations between work-related perceived stress and surface electromyographic (sEMG) parameters (muscle activity and muscle rest) during standardized simulated computer work (typing, editing, precision, and Stroop tasks). It was part of the European case-control study, NEW (Neuromuscular assessment in the Elderly Worker). The present cross-sectional study was based on a questionnaire survey and sEMG measurements among Danish and Swedish female computer users aged 45 or older (n=49). The results show associations between work-related perceived stress and trapezius muscle activity and rest during standardized simulated computer work, and provide partial empirical support for the hypothesized pathway of stress induced muscle activity in the association between an adverse psychosocial work environment and musculoskeletal symptoms in the neck and shoulder.

Pyelonephritis in persons after age 50 as a clinical marker of urogenital cancer.

OBJECTIVES: Urinary tract infections have been linked with urinary tract cancer, but the association remains controversial. We examined whether pyelonephritis is a clinical marker of urogenital cancer. METHODS: We used Danish medical databases to create a population-based cohort of patients with an incident hospital-based pyelonephritis diagnosis during 1994-2013. Follow-up for cancer began at pyelonephritis diagnosis and ended on 30 November 2013. We restricted the cohort to patients older than 50 years, as urogenital cancer risk in the younger population is low. We calculated the absolute risk of urogenital cancer and the standardized incidence ratio (SIR) comparing risk observed in pyelonephritis patients to risk expected in the general population of Denmark. RESULTS: Among 15 070 patients with pyelonephritis, we observed 197 urinary tract cancers and 374 genital organ cancers over a 20-year follow-up period. The absolute risk of urogenital cancer was 1.5% 6 months after a pyelonephritis diagnosis, and the cumulative risk was 3.0% at 5 years. During the first 6 months following a pyelonephritis diagnosis, the SIR of urogenital cancer was 8.56 (95% CI 7.49-9.75). Between 6 and 12 months following this diagnosis, the SIR was 1.75 (95% CI 1.26-2.35), and beyond 1 year the SIR was approximately unity for most cancers. Notably, the SIR for bladder cancer among women remained elevated beyond 1 year of follow-up. CONCLUSIONS: Patients presenting with a hospital-based diagnosis of pyelonephritis had a higher 6-month risk of urogenital cancer than expected. However, causation cannot be inferred because of the study design.

Calcium Fluxes in Work-Related Muscle Disorder: Implications from a Rat Model.

INTRODUCTION: Ca2+ regulatory excitation-contraction coupling properties are key topics of interest in the development of work-related muscle myalgia and may constitute an underlying cause of muscle pain and loss of force generating capacity. METHOD: A well-established rat model of high repetition high force (HRHF) work was used to investigate if such exposure leads to an increase in cytosolic Ca2+ concentration ([Ca2+]i) and changes in sarcoplasmic reticulum (SR) vesicle Ca2+ uptake and release rates. RESULT: Six weeks exposure of rats to HRHF increased indicators of fatigue, pain behaviors, and [Ca2+]i, the latter implied by around 50-100% increases in pCam, as well as in the Ca2+ handling proteins RyR1 and Casq1 accompanied by an ∼10% increased SR Ca2+ uptake rate in extensor and flexor muscles compared to those of control rats. This demonstrated a work-related altered myocellular Ca2+ regulation, SR Ca2+ handling, and SR protein expression. DISCUSSION: These disturbances may mirror intracellular changes in early stages of human work-related myalgic muscle. Increased uptake of Ca2+ into the SR may reflect an early adaptation to avoid a sustained detrimental increase in [Ca2+]i similar to the previous findings of deteriorated Ca2+ regulation and impaired function in fatigued human muscle.

Surgeons' muscle load during robotic-assisted laparoscopy performed with a regular office chair and the preferred of two ergonomic chairs: A pilot study.

Surgeons work in awkward work postures and have high precision demands - well-known risk factors for musculoskeletal pain. Robotic-assisted laparoscopy is expected to be less demanding compared to conventional laparoscopy; however, studies indicate that robotic-assisted laparoscopy is also associated with poor ergonomics and musculoskeletal pain. The ergonomic condition in the robotic console is partially dependent upon the chair provided, which often is a regular office chair. Our study quantified and compared the muscular load during robotic-assisted laparoscopy using one of two custom built ergonomic chairs and a regular office chair. The results demonstrated no differences that could be considered clinically relevant. Overall, the study showed high levels of static and mean muscular activity, increased perceived physical exertion from pre-to-post surgery, and moderate to high risk for musculoskeletal injuries measured by the Rapid Upper Limb Assessment worksheet. Authors advocate for further investigation in surgeons' ergonomics and physical work demands in robotic surgery.

Dizygotic monochorionic twin pregnancy conceived following intracytoplasmic sperm injection treatment and complicated by twin-twin transfusion syndrome and blood chimerism.

We report a case of a dizygotic monochorionic twin pregnancy preceded by intracytoplasmic sperm injection treatment including assisted hatching. On ultrasound examination at 25 weeks' gestation the twins, which had been assumed to be monochorionic, were found to be of different sexes. Karyotyping and zygocity determination were performed on amniotic fluid and showed the twins to be dizygotic with normal female and male karyotypes. There were clinical and sonographic signs of twin-twin transfusion syndrome (TTTS), and Cesarean delivery was performed at 32 weeks' gestation. At birth the twins were phenotypically a normal male and a normal female. Histology of the placenta showed it to be monochorionic diamniotic. Blood chimerism was found postnatally as both infants had the karyotypes 46,XX[13]/46,XY[17]. Chimerism was not found in cells from a buccal swab at 6 months of age. This is one of only a few reported cases of dizygotic monochorionic twins. Nearly all of these cases have been conceived after assisted reproductive technology procedures. It is of clinical importance to be aware of this rare phenomenon in relation to TTTS, prenatal screening and parental counseling.

Trapezius muscle rest time during standardised computer work--a comparison of female computer users with and without self-reported neck/shoulder complaints.

Work related musculoskeletal disorders (WMSDs) in the shoulder/neck area are a common and increasing problem among European computer workers, especially women. Long-term low-level workloads with low degree of muscle rest are a potential risk factor for developing WMSDs. The purpose of the present study of female computer users (age 45-65 years) in Denmark and Sweden was to investigate if subjects with self-reported neck/shoulder complaints (cases, N=35) show less trapezius muscle relative rest time (RRT) than controls (N=44) when performing standardised short-term computer work tasks in controlled laboratory conditions. Surface electromyography (EMG) signals were recorded bilaterally from the upper trapezius muscles during a type, edit, precision and colour word stress task. Besides RRT, 10th percentile RMS values were calculated. On the average, 15 of the cases and 18 of the controls showed analysable EMG files per task. For the colour word stress task, the results showed lower RRT values and higher 10th percentile RMS amplitude levels among cases compared to controls. No such signs could be found for the other tasks performed. The present results indicate an increased motor response to a psychological stressor among subjects with self-reported neck/shoulder complaints.

Occupational and leisure-time physical activity and workload among construction workers - a randomized control study.

BACKGROUND: There is a lack of quantification of occupational physical activity (OPA) and leisure time physical activity (LTPA) among construction workers. OBJECTIVES: To describe physical activity energy expenditure (PAEE), physical workload, and the effect of a PA-intervention among construction workers. METHODS: Sixty-seven Construction workers self-reported their physical activity (PA), had PA assessed directly (PAEE), and observed OPA using the tool "Posture, Activity, Tools and Handling." The PA-intervention (Intervention; n = 29, Controls; n = 24) included 3x20-min training/week for 12 weeks. RESULTS: Baseline median OPA was 5036 MET-min/week and LTPA 2842 MET-min/week, p < 0.01. OPA directly recorded was (mean ± SE): 56.6 ± 3.2 J/kg/min and LTPA was: 35.7 ± 2.2 J/kg/min (p < 0.001). Manual material handling was performed for ≥ 25% of working time by more than 50% of the participants. Post-intervention, the training group reduced overall PAEE compared to the control group but not specifically during work. CONCLUSIONS: OPA was within the maximum recommended level of 1/3 proposed in consensus guidelines but did not decrease with PA-intervention.

Does a combination of physical training, specific exercises and pain education improve health-related quality of life in patients with chronic neck pain? A randomised control trial with a 4-month follow up.

AIM: To investigate the effect of combining pain education, specific exercises and graded physical activity training (exercise) compared with pain education alone (control) on physical health-related quality of life (HR-QoL) in chronic neck pain patients. METHODS: A multicentre randomised controlled trial of 200 neck pain patients receiving pain education. The exercise group received additional exercises for neck/shoulder, balance and oculomotor function, plus graded physical activity training. Patient-reported outcome measures (Short Form-36 Physical and Mental component summary scores, EuroQol-5D, Beck Depression Inventory-II, Neck Disability Index, Pain Bothersomeness, Patient-Specific Functioning Scale, Tampa Scale of Kinesiophobia, Global Perceived Effect) and clinical tests (Aastrand Physical Fitness, cervical Range of Motion, Pressure Pain Threshold at infraspinatus, tibialis anterior and cervical spine, Cranio-cervical Flexion, Cervical Extension muscle function, and oculomotion) were recorded at baseline and after 4 months. RESULTS: The exercise group showed statistically significant improvement in physical HR-QoL, mental HR-QoL, depression, cervical pressure pain threshold, cervical extension movement, muscle function, and oculomotion. Per protocol analyses confirmed these results with additional significant improvements in the exercise group compared with controls. CONCLUSIONS: This multimodal intervention may be an effective intervention for chronic neck pain patients. TRIAL REGISTRATION: The trial was registered on www.ClinicalTrials.govNCT01431261 and at the Regional Scientific Ethics Committee of Southern Denmark S-20100069.

Pain education combined with neck- and aerobic training is more effective at relieving chronic neck pain than pain education alone--A preliminary randomized controlled trial.

OBJECTIVE: To evaluate the effect of training and pain education vs pain education alone, on neck pain, neck muscle activity and postural sway in patients with chronic neck pain. METHODS: Twenty women with chronic neck pain were randomized to receive pain education and specific training (neck-shoulder exercises, balance and aerobic training) (INV), or pain education alone (CTRL). Effect on neck pain, function and Global Perceived Effect (GPE) were measured. Surface electromyography (EMG) was recorded from neck flexor and extensor muscles during performance of the Cranio-Cervical Flexion Test (CCFT) and three postural control tests (two-legged: eyes open and closed, one-legged: eyes open). Sway parameters were calculated. RESULTS: Fifteen participants (CTRL: eight; INV: seven) completed the study. Per protocol analyses showed a larger pain reduction (p = 0.002) for the INV group with tendencies for increased GPE (p = 0.06), reduced sternocleidomastoid activity during the CCFT (p = 0.09), reduced sway length (p = 0.09), and increased neck extensor activity (p = 0.02) during sway compared to the CTRL group. CONCLUSION: Pain education and specific training reduce neck pain more than pain education alone in patients with chronic neck pain. These results provide encouragement for a larger clinical trial to corroborate these observations.

Influence of memory demand and contra lateral activity on muscle activity.

Computer mouse work often includes memory demands and contra lateral activity. This study simulated video display unit (VDU) mouse-work and the focus was on forearm muscle activity as a result of standardised postural loads, memory demands and contra lateral activity. Surface and intramuscular electromyography (EMG) were recorded from the right forearm muscles during finger elevation and rest with and without memory demands and with and without contra lateral activity i.e. activity of the left hand. In most situations, memory demand increased activity in the m. extensor carpi radialis brevis and m. flexor digitalis superficialis. Also contra lateral activity increased activity in situations with and without memory demands. While surface EMG level of the m. extensor digitorum communis did not increase during memory demands, intramuscular EMG level increased when memory demands and contra lateral activity was combined. Influence of memory demands and contra lateral activity were most pronounced, in situations where activity levels were small. We presume that it is not only prolonged time of active computer mouse use that is a risk for development of musculoskeletal disorders, but also the time when people interact with the computer mentally or with the 'non-mouse hand', while resting their 'mouse-hand' on the mouse.

Mechanomyography and electromyography force relationships during concentric, isometric and eccentric contractions.

The purpose of this study was to investigate systematically if complementary knowledge could be obtained from the recordings of electromyography (EMG) and mechanomyography (MMG) signals. EMG and MMG activities were recorded from the first dorsal interosseous muscle during slow concentric, isometric, and eccentric contraction at 0, 25, 50, 75 and 100% of the maximal voluntary contraction (MVC). The combination of the EMG and MMG recordings during voluntary concentric-isometric-eccentric contraction showed significant different non-linear EMG/force and MMG/force relationships (P<0.001). The EMG root mean square (rms) values increased significantly from 0 to 50% MVC during concentric and isometric contraction and up to 75% MVC during eccentric contraction (P<0.05). The MMG rms values increased significantly from 0 to 50% MVC during concentric contraction (P<0.05). The non-linear relationships depended mainly on the type and the level of contraction together with the angular velocity. Furthermore, the type of contraction, the contraction level, and the angular velocity influenced the electromechanical efficiency evaluated as the MMG to EMG ratio (P<0.05). These results highlight that EMG and MMG provide complementary information about the electrical and mechanical activity of the muscle. Different activation strategies seem to be used during graded isometric and anisometric contraction.