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At least 307 records · Page 17Linked to original sources

PubMed1999

[Exit of the retinal central vascular trunk and extent of para-papillary atrophy].

PURPOSE: To evaluate whether the position of the central retinal vessel trunk exit on the lamina cribrosa spatially correlates with the location of parapapillary atrophy in glaucoma. METHODS: Color stereo optic disc photographs of 79 patients with primary or secondary open-angle glaucoma and 53 normal subjects were morphometrically evaluated. We determined the position of the central retinal vessel trunk exit on the lamina cribrosa surface and measured the area of parapapillary atrophy in four 90 degrees quadrants. RESULTS: After correction for normal values, the beta zone area of parapapillary atrophy in the glaucoma eyes was significantly larger, when measured in the disc quadrant most distant to the central retinal vessel trunk exit than as if measured in the quadrant containing the vessel trunk exit. CONCLUSIONS: Position of the central retinal vessel trunk exit on the lamina cribrosa influences the location of parapapillary atrophy in glaucoma. The longer the distance to the central retinal vessel trunk exit, the more enlarged is parapapillary atrophy.

Adult↗

PubMed2001

The reversed and bidirectional elephant trunk technique in the treatment of complex aortic aneurysms.

BACKGROUND: The elephant trunk technique with a free-floating vascular prosthesis was originally developed to facilitate a subsequent operation on the downstream aorta. We present here our experience with further developments of this technique, which we call the reversed elephant trunk and bidirectional elephant trunk. METHODS: Between January 1, 1995, and December 31, 2000, 505 adult and adolescent patients underwent operations of the thoracic aorta. A reversed elephant trunk procedure in 13 patients and a bidirectional elephant trunk procedure in 4 patients was performed to facilitate either subsequent proximal or proximal and distal aortic replacement. Nine patients underwent subsequent aortic arch replacement with the reversed prosthetic portion after a mean interval of 8 +/- 5.5 months, and 2 patients received distal extension by use of the distal portion of the free-floating graft. RESULTS: There was no hospital mortality (30 days) in this small group of patients, and no patient had aortic rupture, malperfusion caused by the technique itself, or thromboembolic complications during the waiting interval between the first and the second operations. Five patients are still being observed until the contiguous aortic size is large enough to require an operation, and one 74-year-old patient declined a second-stage operation. CONCLUSION: The reversed and bidirectional elephant trunk techniques are interesting options that may be suitable for patients having complex abnormalities of the thoracic aorta and thoracoabdominal aorta when the proximal portion of the descending aorta has to be replaced before the aortic arch with or without the ascending aorta or the distal descending aorta with or without the thoracoabdominal aorta.

Adolescent↗

PubMed1995

Effects of symmetry and load absorption of a falling load on 3D trunk muscular moments.

Some epidemiological data have suggested that many physical causes of low back pain such as bending and twisting were, in fact, sudden maximal efforts incidentally carried out at the moment of accident. Sudden loading conditions may be encountered in several circumstances, one of them being the recuperation of a falling load. Such conditions are more likely to occur in conditions of trunk asymmetry. The objective of this study was to determine spinal loadings associated with the reception of a falling box symmetrically and asymmetrically for two mechanisms of load absorption, one limited to the elbows and the other including full absorption with the elbows and lower limbs. It was hypothesized that asymmetrical receptions would be more strenuous for the spine; it was further hypothesized that the full absorption to decelerate the load might be more efficient in reducing the strain in the trunk muscular moments. Nine students in physical education with limited experience in manual materials handling were the subjects of the study. The tasks consisted of receiving a 6.6 kg load falling from a height of 50 cm above the flexed forearms when in a standing position. The subjects were tested with two AMTI force plates and two Locam cameras coupled with two mirrors; dynamic 3D multi-segment models were constructed and the net muscular moments as well as the angular velocities of the trunk relative to pelvis were determined about the three orthogonal axes of the trunk at L5/S1, in twisting, lateral bending, and flexion/extension. The dependent variables included maximal moments, maximal rates of loading for these moments, and the integration of these moments. Statistical analyses were performed to test the main effects of symmetry and absorption and their interaction. The results showed that asymmetrical conditions impose supplementary muscular exertions for trunk muscles, especially the trunk extensors and lateral flexors. Contrary to the proposed hypothesis, full absorption as used in the present study was a condition leading to considerably larger muscular exertions, especially for the loading rates. Thus it was concluded that the process of training for load absorption is essential to effectively decrease the risks of injuries. This factor would merit full consideration in future studies.

Absorption↗

PubMed1995

Isodynamic evaluation of trunk muscles and low-back pain among workers in a steel factory.

A cross-sectional study was conducted to explore the relationship between dynamic parameters of trunk muscle strength and the occurrence of low-back pain (LBP). Isodynamic strength measurements were performed among 31 male maintenance workers with spells of low-back pain in the past 12 months and 28 maintenance workers without a history of low-back pain. In general, workers with low-back pain showed a lower trunk muscle performance than the workers without low-back pain. Only the measures of torque during lateral movement differed significantly between both groups. Regression analysis revealed the importance of the nature of low-back pain for trunk muscle strength. Most parameters of trunk muscle strength were significantly decreased among workers with chronic low-back pain of a rather severe nature, showing reductions from 18% to 50%. None of the work-related risk factors for low-back pain contributed significantly to the prediction of trunk strength measures. The study suggests that isodynamic evaluation of trunk muscle strength may assist in determining objective measures for the severity of low-back pain rather than in evaluating a subject's capability of successfully coping with a specific work load.

Adult↗

PubMed1998

Trunk strength in combined motions of rotation and flexion/extension in normal young adults.

Thirty-eight normal healthy young subjects (14 males, 24 females) with mean ages of 23 years (males) and 21 years (females), performed 36 functional rotational tasks of the trunk. The subject's lower extremities were stabilized in a stabilizing platform, allowing the entire motion of flexion-rotation and extension-rotation to take place in the trunk. Of these tasks, 18 were isometric and the other 18 were isokinetic. The isometric tasks consisted of flexion-rotation and extension-rotation from a 20 degrees, 40 degrees and 60 degrees flexed trunk in 20 degrees, 40 degrees and 60 degrees of axial rotation. The isokinetic activity consisted of flexion-rotation and extension-rotation from upright and flexed postures respectively in 20 degrees, 40 degrees and 60 degrees rotation planes at 15 degrees, 30 degrees and 60 degrees/s angular velocities. The results revealed that the males were significantly stronger than females (p < 0.01) and isometric activities produced significantly greater torque compared to isokinetic efforts (p < 0.01). The degree of trunk flexion was not significant; the angle of rotation, although significant, had only a small effect. The 60 degrees trunk rotation was significantly different from 20 degrees and 40 degrees of trunk rotation. The multiple regressions were all significant (p < 0.01); however, they predicted only 40 to 60% of the variations. Based on the results and analysis, it is suggested that the motion involved rather than the torque may have a consequential effect in the precipitation of back injuries.

Adult↗

PubMed1996

Handgrip and Box Tilting Strategies in Handling: Effect on Stability and Trunk and Knee Efforts.

The purpose of this study was to evaluate the effect of four handgrip-box tilting strategies (right, left, backward, and no tilt of the box) on trunk and knee efforts, body posture, and the stability of 14 participants with limited experience in handling. The tasks consisted of transferring a low-lying box placed in front of the participant to a shelf of the same height at the participant's left. It was hypothesized that tilting the box could reduce trunk and knee efforts as well as body asymmetry, and improve stability. A tridimensional dynamic rigid body model was used to estimate the triaxial net muscular moment magnitudes at the trunk (L5/Sl) and at the knees. An approach to quantify the participants' dynamic stability was also included. Finally, 5 angles were computed to characterize body asymmetries. The results showed that tilting the box affected specific trunk efforts, but did not succeed in reducing trunk asymmetric efforts. However, the tilts were executed in a single direction, and it may be possible that combined tilts of the box could help reduce trunk asymmetric efforts. Tilting the box had little effect on knee loadings, and the left tilt strategy reduced participants' stability. This study showed the importance of considering the position of the box when assessing the risks encountered in asymmetrical handling.

Journal Article↗

PubMed2003

Dual function of Slit2 in repulsion and enhanced migration of trunk, but not vagal, neural crest cells.

Neural crest precursors to the autonomic nervous system form different derivatives depending upon their axial level of origin; for example, vagal, but not trunk, neural crest cells form the enteric ganglia of the gut. Here, we show that Slit2 is expressed at the entrance of the gut, which is selectively invaded by vagal, but not trunk, neural crest. Accordingly, only trunk neural crest cells express Robo receptors. In vivo and in vitro experiments demonstrate that trunk, not vagal, crest cells avoid cells or cell membranes expressing Slit2, thereby contributing to the differential ability of neural crest populations to invade and innervate the gut. Conversely, exposure to soluble Slit2 significantly increases the distance traversed by trunk neural crest cells. These results suggest that Slit2 can act bifunctionally, both repulsing and stimulating the motility of trunk neural crest cells.

Animals↗

PubMed1991

Trunk orientation as the determining factor of the 'contralateral' deficit in the neglect syndrome and as the physical anchor of the internal representation of body orientation in space.

The present study examines which egocentric coordinate system determines the border between the disturbed 'contralateral' and the normal 'ipsilateral' side in patients with hemineglect. Based on the observation of significantly longer reaction times for saccades towards stimuli presented in the left visual field (LVF) in right brain-damaged patients with hemineglect, stimuli were presented randomly to the LVF or RVF and the corresponding saccadic reaction times (SRTs) were compared. Beginning with the standard body position generally used for the investigation of neglect patients, where the midlines of head, trunk and visual field are parallel and oriented straight towards the middle of the projection screen, the spatial relation between orientation of head and trunk midlines and location of the target stimuli was systematically varied while holding the retinal projection of the stimuli constant. The deficit in SRTs towards the LVF in 4 right brain-damaged patients with left-sided hemineglect could be compensated for by turning the patients' trunk to the left, such that both LVF and RVF-stimuli were projected to the right, ipsilateral side of trunk space. The results suggest that the spatial orientation of the trunk midline divides our normal perception of space into an egocentric 'left' and an egocentric 'right' sector and seems to be the decisive factor for determining the neglected 'contralateral' part of space in patients with brain-damage. They indicate that the trunk midline constitutes the physical anchor for calculation of the internal egocentric coordinate frame for representing body position with respect to external objects. The hypothesis of Ventre et al. (1984) that deficient reactions to contralaterally located stimuli in neglect patients could be the result of a displacement of these egocentric coordinates towards the non-neglected, ipsilateral side is discussed.

Adult↗

PubMed1986

Trunk flexion in healthy children aged 3 to 7 years.

I tested 80 male and 80 female subjects between the ages of 3 and 7 years on two exercises of isometric trunk flexor muscle strength (half-hold hooklying position and supine flexion position) and one exercise of isotonic trunk flexor muscle strength (hooklying sit-ups) to establish normative data for trunk flexor musculature capabilities. Measurements included the length of time the half-hold hooklying and supine flexion positions were maintained and the number of repetitions of sit-ups. I found no significant differences between the sexes in performance of the isometric tests. I did find, however, a significant difference between age groups for half-hold hooklying and supine flexion tests (p less than .0001), indicating that the ability to perform isometric trunk flexion improves with age. Height was another significant variable contributing to test results (p less than .0001). Children were able to perform sit-ups consistently at age 6 years only; the male subjects performed an average of 20 more sit-ups than the female subjects (p less than .04). I discuss in this article the possible contribution of neuromuscular maturation and physical growth to the development of normal trunk flexion. The results may be useful to clinicians to assess abnormal trunk flexion accurately in children aged 3 to 7 years.

Abdominal Muscles↗

PubMed2006

Reliability and validity of trunk assessment for people with multiple sclerosis.

BACKGROUND AND PURPOSE: Standardized scales are a prerequisite for rehabilitation and research. This study was designed to determine the reliability and validity of scores on items of the trunk assessment of the Melsbroek Disability Scoring Test (MDST) and Trunk Impairment Scale (TIS) in people with multiple sclerosis (MS). SUBJECTS: Thirty people with MS participated in the study. METHODS: Interrater and test-retest reliability and construct validity were assessed. RESULTS: Kappa and weighted kappa values for the items of the trunk assessment of the MDST ranged from .74 to .95, and the kappa and weighted kappa values for the TIS items ranged from .46 to 1.00. Intraclass correlation coefficients for interrater and test-retest agreement were .93 and .92, respectively, for the trunk assessment of the MDST and .97 and .95, respectively, for the TIS. Bland-Altman analysis showed consistency of scores without observer bias. Construct validity was established. DISCUSSION AND CONCLUSION: The MDST and TIS provide reliable assessments of the trunk and are valid scales for measuring trunk performance in people with MS.

Abdomen↗

PubMed2005

Growth strain in the trunk and branches of Chamaecyparis formosensis and its influence on tree form.

Distributions of growth strains in branches, straight trunks and basal sweeping trunks of Chamaecyparis formosensis Matsum. trees were measured with strain gauges. Microfibril angles (MFAs) of the S2 layer of the cell wall were measured by the iodine deposition method and their relationships with growth strain examined. The magnitude of the compressive stress on the lower side of trunks with a basal sweep was greater than that of the tensile stress at the surface of straight trunks. However, transverse compressive stress was similar around the trunk regardless of whether normal wood or compression wood was present. The released surface growth strains varied with MFA. At MFAs of 20-25 degrees , growth stress changed from tension to compression, and compressive stress increased dramatically in the compression wood region. Branches suffer bending stress due to self-loading. This stress is superimposed on the growth stress. Growth strains on the upper or lower sides of branches were larger than those in the trunks, suggesting that generation of growth stress on the lower sides of branches with extensive compression wood is affected by the gravitational bending stress due to self-loading. We conclude that branch form is affected by the interaction between the bending moment due to self-loading and that due to the asymmetric distribution of growth stress. Growth strain distribution in a branch differed depending on whether the branch was horizontal, upward bending or downward bending.

Biomechanical Phenomena↗

PubMedDate not supplied

Trunk rotatory muscle performance in post-stroke hemiplegic patients.

This study was undertaken to determine whether the direction of trunk rotation would have any effect on trunk muscle performance of post-stroke hemiplegic patients. The design consisted of a nonrandomized control trial in a setting of secondary care (rehabilitation unit at hospital facility). The subjects included 65 hemiplegic patients (50 males) and age-matched 80 healthy controls (38 females). Isokinetic trunk rotatory muscle performance at angular velocities of 60, 120, and 150 degrees per second was measured by using an isokinetic dynamometer (Cybex Torso Rotation Unit). There were no significant differences in the peak torque and best work between the right and left directions of the trunk rotation in the hemiplegic patients or in healthy controls, regardless of the gender of the subjects (paired t test, P > 0.05). The muscle performance of the hemiplegic patients was significantly lower than that of the controls for both genders (t test, P < 0.05). In the hemiplegic patients, the direction of trunk rotation does not affect the trunk rotatory muscle performance, although the performance itself was slightly decreased.

Aged↗

PubMedDate not supplied

Muscle strength of trunk flexion-extension in post-stroke hemiplegic patients.

This study was undertaken to determine muscle strength of trunk flexion-extension in hemiplegic patients after stroke compared with that of normal controls. The design consisted of a nonrandomized control trial in a secondary care setting (a rehabilitation unit at a hospital facility). The subjects included 25 post-stroke male hemiplegic patients and 25 male healthy controls. The maximal peak torques of trunk flexion-extension at angular velocities of 0 degrees (isometric contraction), 60 degrees, 120 degrees, and 150 degrees/s were measured by using an isokinetic dynamometer (Cybex Trunk Extension-Flexion Unit, Cybex, Ronkonkoma, NY). Peak torque of trunk flexion and extension in hemiplegic patients was significantly smaller than that of healthy controls (P < 0.05), except isometric trunk flexion (P > 0.05). The weakness of trunk flexion-extension muscles in hemiplegic patients might be accounted for by the bilateral innervation from the motor cortex, the insufficient use of high threshold motor units, and disuse atrophy.

Abdominal Muscles↗

PubMed1993

Isometric maximal and submaximal trunk extension at different flexed positions in standing. Triaxial torque output and EMG.

Thirty-one healthy men were tested for the effects of trunk-flexion positions (0 degrees, 15 degrees, and 35 degrees) in standing on triaxial torques and electromyogram of 10 trunk muscles during voluntary maximal and submaximal isometric trunk extension. At a more flexed position, both erector spinae and latissimus dorsi showed significantly higher RMS-EMG. The abdominal obliques were coactivated only during 100% maximum voluntary exertion at each posture. In all tests, the rectus abdomini were quiet. Mean maximum extension torque increased significantly at 15 degrees and 35 degrees of trunk flexion. The ratio of extension torque over RMS-EMG of the trunk extensor muscles, called the neuromuscular efficiency ratio (NMER), also increased in the more flexed posture. However, NMER has to be interpreted with caution because it is affected both by posture and exertion levels. The effects of posture on the torque generation capability of the trunk question the validity of the current lifting recommendations.

Abdominal Muscles↗

PubMed1994

Paraspinal precontraction does not enhance isokinetic trunk extension performance.

STUDY DESIGN: This study investigated the influence of isometric contraction of the trunk extensor muscles, immediately preceding maximum effort isokinetic trunk extension (precontraction), on isokinetic performance variables and activation levels of the paraspinal muscles. OBJECTIVES: To determine whether agonist precontraction significantly improved the concentric and eccentric isokinetic trunk extension contraction. SUMMARY OF BACKGROUND DATA: Agonist precontraction has been reported to enhance agonist neural drive and force output of the knee and ankle joints. METHODS: Subjects performed concentric and eccentric isokinetic trunk extension at 60, 90, and 120 deg/sec, each of which were preceded by isometric trunk extension precontraction force equal to 0%, 25%, and 50% body weight. RESULTS: Concentric and eccentric contractions showed general, but no statistically significant performance enhancement with paraspinal precontraction. Eccentric contractions tended to improve to a greater extent than concentric contractions. CONCLUSIONS: It is possible that the addition of agonist precontraction increased the complexity of the trunk extension task, thus requiring a learning period, as is the case with most novel motor skills. There may be meaningful rehabilitation-related implications of the qualitative tendencies observed in the data that merit further consideration.

Adult↗

PubMed1995

Human trunk strength profile in flexion and extension.

STUDY DESIGN: Isometric and isokinetic trunk flexion-extension strengths were studied among 73 subjects (41 males and 32 females) and 10 patients (9 males and 1 female). The isometric strengths were measured in four postures of trunk flexion. The isokinetic trunk strengths were measured through the range of these postures. OBJECTIVES: The study had two objectives: to develop a database for isometric flexion-extension strength at different levels of trunk flexion and isokinetic strength at corresponding angles and to determine the decrement in strength characteristics among patients of idiopathic low back pain. SUMMARY OF BACKGROUND DATA: Though flexion-extension strength among normal subjects and patients has been studied, its variation due to standardized postural change has not been reported extensively. The influence of postural deviation on flexion-extension ratios are also largely unknown. METHODS: To achieve the objectives of the study, a device flexion-extension-lateral flexion tester (FELT) was designed and fabricated. The male and female subjects performed isometric flexion and extension at 0 degree, 20 degrees, 40 degrees and 60 degrees of trunk flexion; and isokinetic flexion starting at neutral posture, and isokinetic extension starting at 60 degrees of trunk flexion. The patients performed isometric flexion and extension in neutral posture only; and isokinetic flexion-extension similar to normal sample. RESULTS: The average strength in each activity was between 70 and 80% of the corresponding peak strength. The isokinetic activity strengths ranged between 60 and 70% of the corresponding isometric activities in each group. The strength of females ranged between 60 and 70% of males. The ANOVA revealed that posture had a significant effect on strength. The multiple regression explained 73% of variance in isometric and 34% in isokinetic modes. CONCLUSIONS: A patient's strength profile should be determined in a posture that simulates activities of daily living to determine impairment and plan rehabilitation.

Adult↗

PubMed1996

A comparison of methods for measuring trunk list. A simple plumbline is the best.

STUDY DESIGN: Trunk list was measured using three different techniques to compare accuracy, precision, and ease of use. OBJECTIVE: To obtain a reproducible technique for further studies of the nature, cause, and clinical relevance of trunk list. SUMMARY OF BACKGROUND DATA: Gravity-induced trunk list is a clinical sign that is frequently observed in patients with low back pain and has been associated with intervertebral disc lesions. METHODS: Patients with trunk list participated in a comparison of three techniques to determine list magnitude and direction. Paired measurements of trunk list were obtained from each patient using three techniques: a plumbline, a projected shadow, and the 3SPACE Isotrak (McDonnell Douglas Electronics Company, Colchester, VT). In addition, intra- and interobserver reliability of list measurement was assessed by comparison of paired measurements by each of two observers. RESULTS: List measurements assessed by the plumbline and the projected shadow techniques were not significantly different, but the Isotrak produced data that differed significantly (P < 0.05) from both of these techniques. Comparison of intra- and interobserver repeatability of list measurement using the plumbline technique indicated no significant difference between repeated measures by each observer or between two observers. CONCLUSIONS: A plumbline is the most useful instrument for measuring static trunk list, but its limitations and the need for standardization of measurement technique must be recognized.

Adult↗

PubMed1997

Spectral and temporal responses of trunk extensor electromyography to an isometric endurance test.

STUDY DESIGN: This study investigated the effect of trunk extensor muscle location on the spectral and temporal electromyographic activity of the muscles during a fatiguing isometric extension of the torso against gravity. OBJECTIVES: To determine the spectral responses of the trunk extensor muscles at more locations than have been studied previously, to determine if fatigue in the knee flexors limits this test, and to quantify the recruitment patterns of the trunk extensor muscles in a group of healthy subjects. SUMMARY OF BACKGROUND DATA: Isometric endurance tests appear to have more value than strength tests in predicting the occurrence of low back pain. Electromyographic activity of trunk extensor muscles during these tests may provide clues to the etiology of neuromuscular-based low back pain. Spectral electromyographic measures appear to be successful discriminators between low back pain patient and normal populations, although which muscles provide the best information is unclear. Likewise, the recruitment patterns of the trunk extensors during fatiguing isometric tasks is not well quantified. METHODS: Ten healthy men performed an isometric trunk endurance test. Surface electromyography was recorded from the erector spinae medially and laterally at vertebral levels of L1 and L3, medially at L5, and from the biceps femoris and gastrocnemius. Spectral parameters were calculated from the Fast Fourier Transform, and temporal parameters were calculated from the root mean square of the raw data. Linear regression was used to determine their responses as a function of time. RESULTS: There was a significant effect of vertebral level and medial-lateral location on the initial median frequency and linear slope of the median frequency regressions. No significant evidence of fatigue in the lower extremities was observed. For most subjects, the temporal response of the surface electromyography was parabolic (concave-down), peaking at 30-50% of the endurance time. CONCLUSION: Establishment of which muscle locations provide the best information and knowledge of the recruitment patterns are essential for the development of clinical diagnostic procedures and rehabilitation protocols.

Adult↗