Relationships between visceral, trunk and whole-body adipose tissue weights by cadaver dissection.

BACKGROUND: Despite the important association of central adiposity and cardiovascular and other risk factors, there are only three reported values for directly weighed visceral adipose tissue (AT). All other reported values are based on medical imaging techniques. OBJECTIVE: The study aimed to investigate the relationships between visceral, trunk and total AT weights in older men and women. METHODS: Data was obtained from the combination of two studies involving the complete dissection of 15 male and 16 female cadavers (age range 55-94 years) and allowed for compartmentation into skin, AT, muscle, bone and a residual component, divided over six body segments: head, trunk, legs and arms. Visceral AT was separated from trunk subcutaneous AT. All tissues were weighed. RESULTS: Visceral AT weights ranged from 0.3 to 5.8 kg. Mean values were 3.00 +/- 1.52 kg (mean +/- SE) for the men and 3.24 +/- 1.67 kg for the women. These were not significantly different (p = 0.68), but visceral AT weight, expressed as a percentage of total body AT weight was significantly greater (p = 0.02) in the men (16.8 +/- 5.4%) than in the women (12.9 +/- 3.5%). Correlations between visceral AT weight and the weight of subcutaneous AT of the trunk were highly significant (men, r = 0.70, women, r = 0.81, p < 0.005), with similar slopes for the two sexes. The correlation coefficients of visceral with total body AT weights were even greater (men, r = 0.83 and women, r = 0.96, p < 0.0001). CONCLUSIONS: In this sample of older Belgians, visceral AT is strongly related to total body adiposity, corresponding to an increment of about 200 g of visceral AT for every kilogram of total AT in men and about 180 g in women. Because of this relationship, techniques such as skinfold calipers and ultrasound for assessing whole body fatness from measurement of only the subcutaneous layer are thus able to account for visceral adiposity.

Anthropometric fractionation of body mass: Matiegka revisited.

In a group of 699 Belgian nursing professionals, we estimated body composition using the four-component anthropometric model, relying on the equations originally formulated by Matiegka in 1921 and later revised by Drinkwater and colleagues. We estimated muscle mass using the more recent formula proposed by Martin and co-workers. A discrepancy was noted between estimated total body mass and 'assessed' mass, suggesting erroneous estimations of the components.

Implications of an adjustable bed height during standard nursing tasks on spinal motion, perceived exertion and muscular activity.

Manual handling is a source of occupational stress, particularly for nursing personnel. High levels of biomechanical strain are associated with lifting and transferring patients, especially when the tasks are performed in flexed and twisted positions that induce an increased risk of functional and musculoskeletal problems. The use of adjustable beds in nursing practice has been suggested as a means of influencing working postures and reducing the muscular demands on nurses. The purpose of this study was to investigate the effects on spinal motion, muscular activity and perceived exertion when nurses had the opportunity to adjust bed height. The measures recorded during the conduct of standardized patient handling tasks were the changes in posture (inclination) and in shape (sagittal bending, side bending, axial rotation). Muscular activity was measured using surface electromyography. Perceived exertion was rated using the 15-graded Borg scale. The range of motion was not influenced by the adjustment of bed height, but rather a shift of the time duration histogram was noticed in the direction of the erect, safer position. The time spent in the safe zone of spinal motion near the erect position was significantly increased and was significantly decreased in the potential health-hazardous zones of spinal motion in the extreme positions. No differences in muscular activity or in perceived exertion were found between the two bed height conditions for any of the muscle groups. It was concluded that the quality of spinal motion is enhanced when the opportunity of adjusting the bed height is offered.

Will the use of different prevalence rates influence the development of a primary prevention programme for low-back problems?

To determine relations to low-back problems (LBP), different prevalence rates are used. The disadvantage of using different selection criteria is that studies are not comparable, except where they provide the same results. The present aim was to establish whether different prevalence selection criteria lead to different answers on a newly formed set of questionnaires. Since this set is new, reliability tests were performed (test-retest and calculations of Cronbach's Alpha, Cohen's Kappa and the intraclass correlation). Results of the questionnaire should form the cornerstones of a primary prevention programme. Altogether 1783 nurses in four Flemish (Belgian) hospitals were questioned. Information was gathered on work circumstances, education, general health, psychosocial factors, leisure activities, family situation and musculoskeletal problems. Four different datasets with variables related to lifetime prevalence LBP, annual prevalence LBP, point prevalence LBP and a set with all related variables were constructed. The variables demonstrating a relation with LBP differed slightly depending on the kind of prevalence used (lifetime, annual, point). A factor analysis on each set of prevalence related data failed due to the lack of homogeneity of the variables. Fear avoidance, coping aspects and musculoskeletal problems in other regions then the lower back were, in all circumstances, the most discriminating variables. Their discriminating power, however, differed depending on the kind of prevalence used. The differences were too small to influence the construction of the prevention programme. It is concluded that in developing a primary prevention programme any of the prevalence rates can be used. The combination of the three types of prevalence rates studied provides the most complete and reliable image.

Muscle strength, task performance and low back load in nurses.

Poor muscle strength, relative to the physical demands of specific jobs, is considered a risk factor for low back pain. To gain an understanding of the underlying mechanisms, this study questioned whether muscle strength was related to task performance and low back load in nursing tasks. Trunk extension, elbow flexion and knee extension strength were therefore measured in 17 nurses. The independent effects of muscle strength on task duration, jerkiness of effort and L5-S1 torque were investigated as the nurses performed several patient handling tasks. Despite a large variation in muscle strength within the subject population, no effect of strength on task duration, jerkiness or L5-S1 torques was observed. In conclusion, poor muscle strength was found not to be related to increased low back load. If 'weaker' nurses were to be at a higher risk, it would be due to a reduced capability to withstand the mechanical load, rather than to an increased mechanical load.

Left-right asymmetries and other common anatomical variants of the first cervical vertebra.

SUMMARY. Left-right asymmetries were systematically and independently observed twice in 82 macerated atlases by three investigators using a check-list and the instructions of an examination protocol. A grid behind the vertebra served as a visual aid and was inserted in an inclinometer box used for measuring zygapophyseal joint facet inclination. Only those asymmetries observed once by each of the investigators were listed. The posterior arch showed the highest number of asymmetries and many unequal grooves for the vertebral artery were observed. The lateral compartment frequently revealed asymmetries of transverse processes and transverse foramina. These results are indicative of variants of the bony canal for passage of the vertebral artery and asymmetric lever arms for muscles, inserted at C1. A third zone could be defined at the level of the joint facets. Tropism of the superior joint facets was caused by differences in shape, size, surface area, curvature, inclination relative to the sagittal plane, implantation on the lateral mass, unilateral or asymmetric subdivision. Left-right differences of inferior joint facets were often related to degenerative enlargement. Osteophytes also caused asymmetry of the facet for the odontoid process. An important number of combined asymmetries reveals questions about their functional consequences. Copyright 1997 Harcourt Publishers Ltd.

Is ergonomic intervention alone sufficient to limit musculoskeletal problems in nurses?

This study retrospectively surveyed 1,216 nurses at hospitals in Belgium and The Netherlands. Data concerning workloads, musculoskeletal symptoms, work loss and psychosocial factors were collected by questionnaire. Lifetime prevalence rates for musculoskeletal problems and low back trouble were significantly lower in the Dutch hospitals than the Belgian hospitals, but a significantly higher proportion of Dutch nurses had 'heavy' workloads. Overall, symptoms and work loss in the previous 12 months were not related to workload, nor was the perception that work was causative; a change of duties because of symptoms was rare (< 3%). The Dutch nurses differed strikingly from Belgian nurses on the psychosocial variables; they were less depressed and significantly more positive about pain, work and activity. It is proposed that ergonomic interventions alone may be sub-optimal in controlling musculoskeletal problems among nurses. The additional provision of psychosocial information to challenge misconceptions and encourage self-management is proposed.

The muscular arch of the axilla revisited: its possible role in the thoracic outlet and shoulder instability syndromes.

SUMMARY. The thoracic outlet syndrome and shoulder instability provoke well known and partly similar sensations, often described by the patient as "my arm feels deadellipsisI have no strength in my armellipsisI feel pins and needles in my armellipsis". In axillary surgery, there are sometimes reports of a fibromuscular band or string crossing the axilla. In the dissection room these bands are well known. Their reported incidence being about 10% at post mortem. Generally they are variations of the latissimus dorsi or the pectoralis major muscles, the most common form being known as the axillary arch or the arch of Langer. Simulations of abduction in combination with external rotation on dissected cadaveric material suggest a possible neurovascular compression at the transition from the axilla to the upper end of the brachial neurovascular bundle. Dissection confirms that the band is innervated by branches from the ansa pectoralis with a blood supply from the lateral thoracic artery. Following a case study, where the axillary arch negatively influenced the patients occupational skills, an extensive echographic study of 1321 subjects (1179 male, 142 female) was undertaken. A total of 188 arches was detected in 112 subjects (8.50%), mostly occurring bilaterally (incidence 5.80%). The incidence of the arch of Langer suggests that it should be considered in the differential diagnoses of thoracic outlet and shoulder instability syndromes. Copyright 1996 Harcourt Publishers Ltd.

Effect of individually chosen bed-height adjustments on the low-back stress of nurses.

OBJECTIVES: The effects of height-adjustable beds in hospitals on the subsequent prevalence of low-back problems among nurses depend on the capacity to reduce low-back stress by bed-height adjustment. This capacity was investigated in the present study. METHODS: Professional nurses performed patient-handling tasks at a standard and an individually chosen bed height. Peak values and time integrals of spinal compression and shear forces were estimated with dynamic biomechanical modeling. RESULTS: The bed-height adjustment led to lower values of time-integrated compression (average 8.8% lower), peak shear force (average 9.3% lower), and time-integrated shear force (average 18.1% lower). No significance was found for the effect on peak compression, nor for the results for each individual task. This finding can be explained by the minor adjustments made in comparison with the standard height or by the application of different criteria for bed-height adjustment. CONCLUSIONS: The decreasing time-integrated forces and peak shear force, without a concomitant rise of peak compression, speak in favor of the use of height-adjustable beds in nursing.