Measuring seating pressure, area, and asymmetry in persons with spinal cord injury

Abstract

IntroductionSpinal cord injury (SCI) occurs in a substantial proportion of trauma. A study from major trauma centers in the United States reports that SCI occurred in 2.6% of trauma patients, or approximately 1 in 40 patients, reported between 1982 and 1989, of whom 79% were male [4]. Wheelchair-ambulating patients with SCI are often susceptible to joint pain, spine deformity, or pressure sores [5,6,9,10,13].Pressure on the seating area alters dramatically after SCI. The muscle atrophy that often results from SCI, combined with the loss of other soft tissues, reduces the area of the surface and the distribution of pressure to the underlying structures. Pressure, defined as force per unit area, increases rapidly with decreasing contact area. High pressures on the seating surface lead to pressure sores, a major concern of persons with SCI for both health and quality-of-life reasons.Asymmetry of static sitting in SCI has been little studied in the literature. Complications such as spine deformity, a common secondary effect of muscle imbalance, and loss of sensory ability and perception may lead to an asymmetry in loading. This asymmetry will further exacerbate the consequences of high pressures on the loading area [13].Abstract The goal of this study was to measure characteristics of seat loading in manual wheelchair users with complete spinal cord injury (SCI). Pressure distribution on the seating area of 25 adult males with SCI and eight non-injured adult males was measured in a relaxed and an upright posture on a standardized hard surface. Subjects with SCI were also tested in their wheelchairs. Maximum pressure, contact area, area of the highest pressure, and three asymmetry indices were compared. Subjects with SCI have higher pressure distributed over a smaller area, have a much smaller contact area, and distribute the loading more asymmetrically than non-injured subjects. Upright posture only corrects for some loading problems, while the wheelchair corrects for more loading parameters. Routine clinical seat loading evaluation may lead to improved chair and cushion selection for patients with SCI and may even alert clinicians to patients at high risk for complications due to high or unbalanced loads.

Study of the pressures applied by a Chêneau brace for correction of adolescent idiopathic scoliosis

“…We used the TekScan 1 system, which is based on a technique described by Gutierrez et al (2004). It includes a ClinSeat 1 pressure sensor, connected to a USB handle (ClinSeat Type 5315 Sensor, TekScan, Boston MA, USA) (Figure 2).…”

“…The manufacturer's pressure sensors have been validated in another application (Luo et al 1998;Gutierrez et al 2004). The Chêneau brace's three points of support are presented in Figure 2.…”

Evaluation and Study on Relationship between Sitting Posture and Work Efficiency

“…The requirement for the optimum sitting posture during office work is that the pressure it caused can be distributed in the intervertebral discs of the vertebrae in the most appropriate way and deal load it produced can be distributed in attached muscular tissues [4] in the appropriate and even way. Among these three sitting postures, trunk straightening up is the popularly required " ideal posture " and " healthy posture " .…”

Gluteal blood flow and oxygenation during electrical stimulation-induced muscle activation versus pressure relief movements in wheelchair users with a spinal cord injury

“…Throughout their life, up to 80% of people with an SCI suffer from a PU, 1,2 leading to radical consequences such as decreased mobility and independence, delayed rehabilitation, and exclusion from social activities, 2,3 and it has a tremendous impact on the individual's physical condition. 3,4 The consequences also result in high costs for the community.…”

“…Throughout their life, up to 80% of people with an SCI suffer from a PU, 1,2 leading to radical consequences such as decreased mobility and independence, delayed rehabilitation, and exclusion from social activities, 2,3 and it has a tremendous impact on the individual's physical condition. 3,4 The consequences also result in high costs for the community. 4,5 Shifting posture regularly, on average eight times an hour, prevents healthy individuals from developing PUs, as subcutaneous oxygenation increases with each posture adjustment.…”