Neuromusculoskeletal disorders in the neck and upper extremities among drivers of all-terrain vehicles--a case series

Rapidly growing intramuscular lipoma: a unique entity of benign lipomas in children

This report presents a case of an intramuscular lipoma observed in the left back of a healthy female toddler. It was resected after 3 months of observation because of rapid enlargement, raising suspicion of malignancy. Histopathological examination confirmed a diagnosis of intramuscular lipoma without malignant and blastemal components. Intramuscular lipomas are benign neoplasms that mostly appear as a rapidly growing tumour. Several hypotheses regarding the pathogenesis of this characteristic growth pattern have been proposed, including atrophy of the surrounding muscle, reactive adipocytic neoformation and multiple contractive interactions between the lipoma and the surrounding muscle.

The Vehicle Seating Intervention Trial: Cross-Over Randomized Controlled Trial to Evaluate the Impact of 2 Car Seat Configurations on Spinal Posture

Driving posture can lead to musculoskeletal pain. Most work focuses on the lower back; therefore, we know little about automobile seat design and neck posture. This study evaluated an automobile driver seat that individualized upper back support to improve head and neck posture. Specifically, we examined the system's impact on anterior head translation with secondary outcomes of spine posture and perceptions of comfort/well-being compared with a control. Forty participants were block randomized to experience either the activated or deactivated version of the same seating system first. Participants completed two 30-minute simulated driving trials, separated by washout, with continuous measures of anterior head translation, spine posture, and pelvis orientation. Perceptions of comfort/well-being were assessed by survey and open-ended questions immediately following each condition. Small, but statistically significant decreases in anterior head translation and posterior pelvic tilt occurred with the activated seat system. Participants reported lower satisfaction with the activated seat system. Order of the 2 seat conditions affected differences in pelvis orientation and participant perceptions of comfort/well-being. An anthropometric-based seat system targeting upper back support can significantly affect head and pelvic posture but not satisfaction during simulated driving. Future work should examine long-term impacts of these posture changes on health outcomes.

Spatiotemporal gait parameters in young individuals wearing an age simulation suit compared to healthy older individuals

INTRODUCTION

Aging is accompanied by changes in muscle mass, strength and loss of sensory, visual and auditive functions. However, these changes do not occur linearly, most spatiotemporal gait parameters change with aging. Age simulation suits have been invented to give young people an impression of the implications of being older and may be a useful tool in the scientific setting for gerontology research to validate any study concept before it becomes a pilot study. The rationale behind this study was to investigate the effects of an age simulation suit on gait parameters in young healthy adults and to compare the altered gait with healthy older, community-dwelling citizens.

METHODS

Subjects were 14 healthy young adults (6 female) and 8 healthy older (4 female) individuals with a mean (± SD) age of 24.8 ± 3.4 years and 72 ± 1.9 years, respectively. After initial baseline measurements had been taken and a familiarization phase, the younger subjects walked for 15 min without and 15 min with an age simulation suit on an instrumented treadmill. The older subjects walked once for 15 min on the same treadmill without wearing an age simulation suit. The walking speed was self-selected for all subjects.

RESULTS

The age simulation suit reduced the walking speed from 4.1 ± 0.7 km/h to 3.3 ± 0.5 km/h (p < 0.001) in young adults with no differences compared to older adults (2.9 ± 0.6 km/h, p = 0.9). Step width increased from 8.7 ± 2.2 cm to 12.1 ± 2.2 cm (p < 0.001) and did not differ from older participants (11.1 ± 4.3 cm, p = 0.37). The stride length was reduced (132.6 ± 5.9 cm vs 118.1 +-6.6 cm, p < 0.001), but still did not match the old control group (94.5 ± 5.6 cm, p < 0.05). Wearing the suit increased thestride time of young subjects (from 1,152 to 1,316 ms, p < 0.001) and was different compared to the older control group (1,172 ms, p = 0.53). The coefficient of variation (COV) of spatiotemporal parameters did not differ between young (both not wearing the suit and wearing the suit) and older subjects. The standard deviation of lateral symmetry, an in-house marker from the instrumented treadmill that serves as a marker of gait variability, differed between young subjects without the suit and older subjects (5.89 ± 1.9 mm vs 14.6 ± 5.7 mm, p < 0.001) but not between young subjects wearing the suit and older subjects (16.4 ± 7.4 mm vs 14.6 ± 5.7 mm, p = 0.53).

CONCLUSION

Wearing an age simulation suit while walking on a treadmill with a self-selected walking speed alters some, but not all, measured spatiotemporal parameters to approximate a gait pattern similar to that of an older individual.

Double-Sided Mechanical Shocks Provoke Larger Seated Postural Reactions Compared With Single-Sided Mechanical Shocks

STUDY DESIGN

Human volunteers were exposed experimentally to single-sided mechanical shocks (SSMS) and double-sided mechanical shocks (DSMS) while seated.

OBJECTIVE

The aim of this study was to describe and contrast seated postural reactions due to SSMS or DSMS in healthy male adults.

SUMMARY OF BACKGROUND DATA

Mechanical shocks to the body, caused when driving on irregular terrain, are suggested to be hazardous to the spine and may be associated with the reported musculoskeletal pain of the back and neck among professional drivers. However, very little is known about the characteristics of seated postural reactions and the biomechanical effects caused by mechanical shocks.

METHODS

Twenty healthy male subjects (18-43 years old) were exposed while seated to 5 SSMS and 15 DSMS in lateral directions. The second acceleration in the DSMS was in the opposite direction to the first acceleration and was fast, medium, or slow depending on the speed of direction change. Surface electromyography (EMG) was recorded in muscles of the upper neck, trapezius, erector spinae, and external oblique, while kinematics were recorded with inertial sensors placed at the neck, trunk, and pelvis. Muscle activity was normalized to maximum voluntary contractions (MVCs).

RESULTS

The EMG amplitudes were significantly higher (0.6-1%; P < 0.001) for the fast DSMS than all other shocks. Range of motion (ROM) of the neck and trunk was greater during the DSMS than the SSMS. Evoked muscle activity was less than 2% MVC in the trapezius, less than 10% MVC in the erector spinae and upper neck, while the activity exceeded 10% MVC in the external oblique muscles.

CONCLUSION

Fast DSMS in lateral directions appear more demanding than SSMS, demonstrating augmented seated postural reactions. However, the present mechanical shocks employed did not seem to induce postural reactions with regard to ROM or muscle activity of a magnitude likely to cause musculoskeletal overload.

LEVEL OF EVIDENCE

4.

The effect of a multifaceted ergonomic intervention program on reducing musculoskeletal disorders in dentists

Background: Work-related musculoskeletal disorders (WMSDs) are the most common occupational injuries in dentists. These disorders occur due to the specific characteristics of dentistry occupation such as the use of tools and instruments and awkward posture. The present study aimed at evaluating the effect of multifaceted ergonomic program on reducing musculoskeletal disorders in dentists. Methods: One hundred-two male dentists who worked in dentistry clinics of Tehran's hospitals participated in this interventional study. Participants were randomly divided into control (n=50) and intervention (n=52) groups. Dentists in the intervention group (n=52) underwent multifaceted ergonomic intervention program for 8 weeks and dentists in the control group (n=50) only received the measurements. The prevalence of musculoskeletal disorders was evaluated in each of the 2 groups at 3 time points before the intervention, 3, and 6 months after the intervention using the Nordic Musculoskeletal Questionnaire (NMQ). Paired t-test was used to compare the prevalence of musculoskeletal disorders before and after the ergonomic intervention program at the end of 3 and 6 months. Results: The results revealed that the prevalence of musculoskeletal disorders was reduced after the intervention in the neck, shoulder, arm, wrist, back, thigh, knees, and feet (p<0.05). On the other hand, the prevalence of musculoskeletal disorders increased in the control group in the neck, shoulder, arm, wrist, thigh, and knee, respectively. The survey results revealed that 98% of the participants agreed with this intervention program. Conclusion: The results of this study revealed that the multifaceted ergonomic intervention program, which included improving working conditions, identifying ergonomic risk factors, regular exercise, and discussion group meetings, could decrease the prevalence of musculoskeletal disorders in dentists.

Effects of l-Carnitine Supplementation on Serum Inflammatory Factors and Matrix Metalloproteinase Enzymes in Females with Knee Osteoarthritis: A Randomized, Double-Blind, Placebo-Controlled Pilot Study

OBJECTIVE

Considering the importance of inflammation in the pathogenesis of osteoarthritis (OA) and induction of pain, this study was aimed to investigate the effect of L-carnitine supplementation on serum inflammatory mediators and OA-associated pain in females with knee OA.

METHODS

In this clinical trial, 72 females with mild to moderate knee osteoarthritis started the study, divided into 2 groups to receive 750 mg/day L-carnitine (n = 36) or placebo (n = 36) for 8 weeks. Serum levels of Interleukine-1β (IL-1β), high-sensitivity C-reactive protein (hs-CRP), matrix metalloproteinases (MMPs)-1 and -13, and visual analog scale (VAS) for pain were assessed before and after supplementation. Data were analyzed by t test, Wilcoxon signed rank test, Mann-Whitney U test, and analysis of covariance.

RESULTS

Only 69 patients (33 in the L-carnitine group and 36 in the placebo group) completed the study. L-Carnitine supplementation decreased serum IL-1β and MMP-1 levels significantly (p = 0.001 and p = 0.021, respectively); however, serum hs-CRP and MMP-13 levels did not change significantly (p > 0.05). In the placebo group, serum IL-1β levels increased significantly (p = 0.011), whereas other studied biomarkers did not change significantly. The mean VAS score decreased significantly in the L-carnitine and placebo groups by 52.67% and 21.82%, respectively (p < 0.001). Significant differences were only observed between the 2 groups in serum IL-1β (p < 0.001) and MMP-1 (p = 0.006) levels and mean VAS score (p = 0.002) after adjusting for baseline values and covariates.

CONCLUSION

Despite observed beneficial effects of short-term supplementation of L-carnitine in decreasing serum inflammatory mediators and improving pain in knee OA patients, further studies are needed to achieve concise conclusions.

Effects of vehicle-ride exposure on cervical pathology: a meta-analysis

Research to date on the effect vehicle-ride exposure has on the development of cervical pathologies in mounted Warfighters is conflicting. The purpose of this study was to determine if the literature suggests a definite effect of vehicle-ride exposure on cervical pathology. Databases were searched using multiple combinations of select terms. Twelve studies meeting the inclusion criteria were included in the meta-analysis. The results of the meta-analysis revealed that overall vehicle-ride exposure was likely to increase cervical pathology (p=0.01, odds ratio=1.59, 95% CI=1.16-2.17). Using vehicle type as a moderator it was found that vehicle-ride exposure in ground-based vehicles (p=0.01, odds ratio=2.33, 95% CI=1.41-3.85) and fixed-wing aircraft (p=0.01, odds ratio =1.59, 95% CI=1.13-2.23) were likely to increase cervical pathology. Using operator/other personnel moderator it was found that in the populations tested, fighter pilots or fighter jet weapons systems operators were more likely to develop a cervical pathology (p<0.001, odds ratio=1.78, 95% CI=1.26-2.50). The available studies indicate an increase in cervical pathology for personnel exposed to ground-based vehicles and fixed-wing aircraft.

Adoption of preventive measures after returning to work among workers affected by De Quervain's tenosynovitis

OBJECTIVES

To determine whether if there was any increase in preventive measures adopted following reincorporation to their jobs among workers affected by De Quervain's tenosynovitis (DQT), who were treated by surgical intervention.

METHODS

Study subjects where those workers, members of a mutual health insurance scheme, who were operated on between June 2006 and June 2009 (n=52). For each worker we checked whether preventive measures had been taken in their workplace, both before their episode, and following reincorporation. The difference in proportions (DP) was calculated between the proportion of individuals with preventive measures after reincorporation and the proportion with preventive measures implemented prior to their surgical intervention, both globally and in terms of sociodemographic, occupational, and clinical variables.

RESULTS

The proportion of workers with preventive measures adopted following reincorporation to their job was higher than the proportion with preventive measures prior to their surgical intervention (DP = 23.1 %; 95 %CI: 6.4-39.7 %). The risk factors associated with the greatest change in preventive measures were repetitive movements (DP = 25.6 %; 95 %CI: 6.1-45.1 %) and awkward postures (DP = 40 %; 95 %CI: -22.9 to 100 %).

CONCLUSIONS

Despite the increased proportion of workers with preventive measures implemented in their workplace following reincorporation to the job, there is a lack of information and of adoption of ergonomic preventive measures specific to this pathology. Implementation of ergonomic programs could reduce incidence of musculoskeletal disorders such as DQT, and would thus increase productivity, efficiency and worker satisfaction, while diminishing sick leave episodes, and the associated costs and relapses.

Cervical spine rotation and range of motion: pilot measurements during driving

OBJECTIVE

Previous studies have evaluated the cervical range of axial rotation during simulated driving conditions. The goals of this pilot study were to describe cervical spine rotation during in-car driving and determine the percentage of time outside neutral neck rotation and peak cervical axial rotation angles that the subjects adopted during various driving conditions.

METHODS

Subjects drove around a specified route through the city of Guelph, Ontario, which included residential, thruway, and highway driving; additional minor driving tasks, such as lane changes, were also included. The cervical range of motion was measured continuously throughout the drive using an electromagnetic sensor; we also used videotape to document the specific driving tasks.

RESULTS

The subjects spent 87.0 percent (SD=8.8) of time with their cervical spine in the neutral axial rotation position (±15 degrees). The percentage of time that the subjects spent outside of the neutral range of cervical axial rotation depended upon the driving section (including residential, thruway, and highway), and driving task being performed (starts, stops, and lane changes). The subjects spent a significantly greater proportion of time with their necks rotated beyond neutral during residential driving compared to thruway and highway driving (19.1% SD=8.3 vs. 10.7% SD=9.5 and 9.3% SD=8.7, respectively; p<.001). During driving, the peak angles of cervical axial rotation were an average of 35.7 degrees (SD=14.2) left and 42.5 degrees (SD=18.0) right.

CONCLUSIONS

We observed a large degree of variability in cervical axial rotation during driving. We observed that most of the driving tasks related to stopping had increased proportion of time out of neutral rotation. Also, right-hand lane changes increased time out of neutral rotation more than left-hand lane changes. Drivers routinely adopt nonneutral head positions (on average 13% of the time); this is likely not enough to lead to injury.

The impact of self-reported exposure to whole-body-vibrations on the risk of disability pension among men: a 15 year prospective study

BACKGROUND

Whole-body-vibrations are often associated with adverse health effect but the long term effects are less known. This study investigates the association between occupational exposures to whole-body vibrations, and subsequent transition to disability pension.

METHODS

A total of 4215 male employees were followed up for subsequent disability pension retirement. Exposure to whole-body-vibration was self-reported while new cases of disability pension were retrieved from a national register.

RESULTS

The hazard ratio (HR) for disability pension retirement among men exposed to whole-body-vibrations was 1.61 (95% confidence interval (CI) 1.07-2.40) after adjustment for age, smoking habits, BMI, physical job demands and awkward work postures. In our model, with the available explanatory variables, 5.6% of the male disability pension cases were attributable to whole-body-vibrations.

CONCLUSIONS

Exposure to whole-body-vibrations predicts subsequent disability pension retirement. Continued reduction of whole-body-vibrations may reduce the number of new cases of disability pension.

Neck pain combined with arm pain among professional drivers of forest machines and the association with whole-body vibration exposure

The purpose of this study was to investigate the existence of neck pain and arm pain among professional forest machine drivers and to find out if pain were related to their whole-body vibration (WBV) exposure. A self-administered questionnaire was sent to 529 forest machine drivers in northern Sweden and the response was 63%. Two pain groups were formed; 1) neck pain; 2) neck pain combined with arm pain. From WBV exposure data (recent measurements made according to ISO 2631-1, available information from reports) and from the self-administered questionnaire, 14 various WBV exposure/dose measures were calculated for each driver. The prevalence of neck pain reported both for the previous 12 months and for the previous 7 d was 34% and more than half of them reported neck pain combined with pain in one or both arms. Analysis showed no significant association between neck pain and high WBV exposure; however, cases with neck pain more often experienced shocks and jolts in the vehicle as uncomfortable. There was no significant association between the 14 WBV measures and type of neck pain (neck pain vs. neck pain combined with arm pain). It seems as if characteristics of WBV exposure can explain neither existence nor the type of neck pain amongst professional drivers of forest machines. The logging industry is important for several industrialised countries. Drivers of forest machines frequently report neuromusculoskeletal pain from the neck. The type of neck pain is important for the decision of treatment modality and may be associated with exposure characteristics at work.

Shoulder reconstruction in obstetric brachial plexus palsy in older children via a one-stage release and tendon transfers

Shoulder contracture from obstetric palsy was surgically released in 24 older children, with simultaneous transfer of the latissimus dorsi and teres major tendons to the posterolateral humerus or rotator cuff. The mean age at surgery was 8 years 11 months. The children were evaluated at a mean follow-up time of 6 years 8 months by the Modified American Shoulder and Elbow Surgeons Form and Shoulder Pain and Disability Index standardized shoulder assessment forms, a questionnaire assessing activities of daily living, and parent and patient satisfaction scales. The fixed internal rotation deformity of 30 degrees +/- 12 degrees improved to 72.5 degrees +/- 27 degrees of external rotation. Improvements of 65 degrees +/- 26 degrees and 47 degrees +/- 33 degrees were seen in abduction and forward elevation, respectively, all without preoperative casting or manipulation. Increased external rotation had a more positive correlation with a higher functional score than abduction. Patients with lower preoperative functional scores had more rotational gain and higher functional scores after surgery. Those aged over 9 years had a functional gain similar to that of the younger children.

Brace treatment for osteoarthritis of the knee: a prospective randomized multi-centre trial

OBJECTIVE

To evaluate the effect of a brace intended to reduce load in patients with medial or lateral compartmental osteoarthritis (OA) and concurrent varus or valgus alignment, respectively.

DESIGN

This multi-centre randomized controlled trial (performed 2001-2003) studies the additive effect of a brace intended to reduce load in conservative treatment of unicompartmental OA of the knee.

SETTING

Orthopedic department of a university medical centre and of one general hospital. The follow-up was 12 months.

PATIENTS

117 patients with unicompartmental OA of the knee. Intervention group (n=60) comprising conservative treatment with additional brace treatment and a control group (n=57) comprising conservative treatment alone.

PRIMARY OUTCOME MEASURES

Pain severity and knee function score.

SECONDARY OUTCOME MEASURES

Walking distance and quality of life.

ANALYSIS

Multiple linear regression models according to the intention-to-treat-principle were used to assess outcome differences for the entire group of patients. In addition, we performed explorative subgroup analyses on primary overall outcomes stratified for alignment, degree of OA, origin of OA, and age.

RESULTS

Although the primary outcome measures were improved in the intervention group in comparison with the controls at each assessment point, the differences reached only borderline significance. The reported walking distances at 3 months, 12 months and overall were significantly longer in the brace group (P=0.03, P=0.04 and P=0.02, respectively). Subgroup analysis showed a better effect in the varus group, in patients with severe OA, in patients with secondary OA and in patients younger then 60 years. In total 25 patients in the brace group and 14 in the control group changed their initial treatment, mostly (74%) because of a lack of beneficial effect.

CONCLUSIONS

The results indicate that a brace intended to reduce load shows small effects in patients with unicompartmental OA. However, many patients do not adhere in the long run to this kind of conservative treatment.