Biomedical subjects

L L van Deursen

Publications and source records attributed to L L van Deursen.

5 recordsLinked to original sources

PubMed2005

Relationship between everyday activities and spinal shrinkage.

BACKGROUND: Purpose of this study was to determine the spinal shrinkage in several activities of daily life and to assess a relationship with intradiscal pressure during these activities. Low back pain is thought to be related to spinal load. In a clinical evaluation of low back pain as provoked by everyday activities, we found a relationship between the amount of complaints during static activities and intradiscal pressure. However, because invasive intradiscal pressure measurements during dynamic activities like walking and cycling are complicated and hardly done before, an analogue relationship between low back complaints and dynamic activities is lacking. METHODS: Therefore spinal load was ascertained by stadiometric measurement of the decrease in standing height, so-called "spinal shrinkage", quantified by the exposure of a 1-h adopted posture or activity. Ten subjects performed five daily life activities: standing, sitting, walking, cycling and lying down. FINDINGS: By doing different activities during 1 h, immediate after getting up in the morning, following average values for shrinkage were measured: standing -7.4 mm (SD 0.5); sitting -5.0 mm (SD 0.6); walking -7.9 mm (SD 0.5); cycling -3.7 mm (SD 0.4) and lying down +0.4 mm (SD 0.5). INTERPRETATION: Overall, good correlation was found between spinal shrinkage and intradiscal pressure. The use of spinal shrinkage measurement seems a good alternative for intradiscal pressure measurement in static situations, but is still questionable in dynamic situations.

Activities of Daily Living↗

PubMed2001

The effect of passive vertebral rotation on pressure in the nucleus pulposus.

To study the immediate effects of axial rotation on the intervertebral disc, six pig cadaver lumbar functional spinal units were exposed to rotations of up to 2 degrees, while disc height and intradiscal pressure were measured. The results showed that rotary movements are capable of causing an immediate increase in disc height and drop in nucleus pressure. However, the long-term effects were opposite in direction.

Analysis of Variance↗

PubMed2000

Length of the spine while sitting on a new concept for an office chair.

Changes in spinal length were used to evaluate a new concept for an office chair. This so-called dynamic chair imparts passive forced motion to the seated subject. The passive forced motion is a rotary movement about an axis, perpendicular to the seat with amplitude of 0.6 degrees and a frequency of 0.08 Hz. Change of stature is assumed to provide a measure for spinal load. Eight subjects were measured in two situations: static (without motion) and dynamic. In both situations the same office tasks were performed and the duration of the sitting period was 1 h. To allow for the normal shrinkage curve the starting time was the same on each of the measurement days. The results indicated a significant difference: when sitting on the dynamic chair the average spinal length increased in comparison to the spinal length in the static chair, where average spinal length decreased. It was concluded that there is spinal distress relief due to the passive motion of the chair.

Adult↗

PubMed2000

Spinal load changes during rotatory dynamic sitting.

OBJECTIVE: To measure load and moment changes acting on the lumbar spine during rotatory sitting. BACKGROUND: A new chair concept generating dynamic stimuli by alternating rotations in the horizontal plane of the chair's seat was recently developed. METHODS: Load and moment changes were measured telemetrically with a spinal fixator device in vivo. RESULTS: A rotatory frequency of 0.22 Hz with an amplitude of 1.8 degrees to the right and left side showed maximum axial force changes in the fixator of 23 N and maximum bending moment changes of 0.52 Nm. CONCLUSIONS: Lumbar force and moment changes during dynamic sitting occur, although only one patient was included in the study. Reasons could be temporary muscular activation in order to adapt the body's equilibrium conditions at the end-point rotation. RelevanceOur measurements suggest that a rotatory chair does have an effect on lumbar spine forces. It becomes more likely that this concept could improve the discs' nutrition and may prevent low back pain.

Adult↗

PubMed1999

Sitting and low back pain: the positive effect of rotary dynamic stimuli during prolonged sitting.

In this study the effect of dynamic stimuli on low back pain during prolonged sitting was investigated. The pain experience of two groups of 60 subjects with a specific low back pain was recorded. All subjects were investigated on pain behaviour by the Multidimensional Pain Inventory (MPI) and pain was measured on an open visual analogue scale (VAS). During sitting, one group received dynamic stimuli that were generated by alternating rotations in the horizontal plane of the seat of the chair, with back and arm rests in fixed position. Two different frequencies of rotation were applied in subgroups. The authors concluded that such stimuli, especially of the lower frequency, reduced pain in prolonged sitting.

Adult↗