Maintaining skin integrity is a critical aspect of overall health, particularly for individuals who spend extended periods in seated positions. Skin shearing is a significant concern in seating, as it can lead to discomfort, deep tissue damage, and an increased risk of pressure injuries. Unlike friction, which affects only the surface of the skin, shear forces act beneath the surface, pulling and distorting deeper layers of tissue. Understanding how shear occurs and implementing effective prevention strategies can make a significant difference in reducing the risk of sheared skin and associated complications.
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What is Shear?
Shear occurs when layers of tissue move in opposite directions, leading to potential damage beneath the skin’s surface. It differs from friction, which primarily affects the skin’s outermost layer. While friction results in minor abrasions or skin tears, shear forces cause deeper structural damage that can impair circulation and cellular health.
Friction happens when the skin rubs against a surface, such as a seat cover, during movement. In contrast, shear occurs when the skin remains stationary while deeper tissues shift, such as when a person slides down in a chair. The mechanical force of shear acts parallel to the skin, affecting deeper layers of tissue and increasing the risk of injury. According to Advances in Skin & Wound Care, shear is influenced by factors such as the amount of pressure exerted, the coefficient of friction between materials, and the extent of contact between the body and the support surface. Because friction and shear often occur together, they can significantly increase the likelihood of skin breakdown.
What Causes Shearing of the Skin?
Shearing forces can lead to deep tissue damage, particularly in areas where bony prominences and soft tissue interact. Common problem areas include:
Sacral Region
The sacral region, or lower back and buttock area, is particularly vulnerable to shear because the skin often adheres to the seating surface while underlying tissues shift. This is a high-risk area for pressure injuries, making shear prevention especially important.
Ischial Tuberosities
The ischial tuberosities, which are the bony prominences in the buttocks, bear significant pressure when seated and are prone to shear forces, especially if a person slides forward or shifts frequently in their seat.
Greater Trochanters
The greater trochanters, or the lateral hip area, can experience shear when there is excessive movement within the seating system, particularly if a person frequently repositions without adequate support.
Heels
The heels are another common site for shearing injuries, as prolonged pressure and subtle movements can cause deep tissue damage over time. Because heels often rest against firm surfaces, they are especially susceptible to the effects of both friction and shear.
Other bony prominences, such as the elbows and occiput (back of the head), can also be affected when the skin remains fixed against a surface while deeper tissues slide. Any situation where the body moves while the skin remains stationary can lead to sheared skin and potential complications.
How to Prevent Shearing of the Skin
Preventing skin shear requires a combination of proper positioning, material selection, and movement strategies. Choosing the right seating system and using appropriate materials can help minimise shear forces and maintain skin integrity.
Seating Fabrics
Seating fabrics play a crucial role in reducing shear. Low-friction, moisture-wicking fabrics can help prevent the skin from sticking to the seating surface. Breathable materials can also help regulate temperature and moisture, reducing the risk of skin breakdown due to prolonged contact.
Properties of vapour-permeable fabric
Tilt-in-space Seating
Tilt-in-space seating is one of the most effective strategies for preventing shearing injuries. This feature allows the entire seat and backrest to tilt backward while maintaining the user’s position relative to the seating system. By redistributing pressure away from high-risk areas, tilt-in-space technology prevents the downward sliding that commonly leads to shear forces. It also helps maintain proper posture and positioning, reducing the likelihood of excessive movement that can contribute to shearing.
Tilt-in-space functionality
Reducing Back Recline Usage
Excessive use of back recline can increase the risk of shear injuries. When reclining, the user may slide down the backrest, causing shear forces between the skin and deeper tissues. The same effect occurs when returning to an upright position, further contributing to shear-related damage. Instead of frequent reclining, tilt-in-space seating should be used to maintain posture and redistribute pressure without creating sliding movements. If a user is vulnerable to pressure ulcers, many healthcare professionals advocate setting the backrest recline to a fixed angle and locking it in that position to minimise unnecessary movement and shear risk.
These armchairs also recline to raise the legs and tilt the backrest backwards for ultimate comfort.
Pressure Redistribution
Pressure redistribution cushions can also minimise shear risk by adapting to body movements and evenly distributing pressure. These cushions are designed to contour to the user’s body, reducing the likelihood of excessive pressure on bony prominences. Gel, air, or foam-based cushions are commonly used to enhance support and reduce shear forces in individuals who require extended periods of seated support.
Levels of pressure relief in pressure care cushions
Positioning and Support
Proper positioning is key to preventing shearing injuries. Ensuring that a person is seated with proper support can minimise unnecessary movement and reduce the risk of sliding. The knees should be at a comfortable angle, with feet resting on a stable surface to provide balanced weight distribution. Positioning aids, such as lateral supports or pelvic belts, can help maintain stability and prevent shifts that contribute to shear.
Repositioning
Regular repositioning is another essential strategy. Encouraging individuals to shift their position frequently, even slightly, can alleviate prolonged shear forces. Caregivers and individuals should incorporate regular weight shifts and micro-movements to reduce continuous pressure on vulnerable areas.
Skin Inspections
Skin inspections should be performed regularly to detect early signs of damage. Checking for redness, irritation, or other indicators of shearing injuries can help address concerns before they progress into more serious wounds. Early intervention is key to preventing complications associated with deep tissue injuries.
Summary
By following these strategies, individuals can significantly reduce the risk of skin shear and maintain healthier skin integrity while seated for extended periods. Proper seating choices, proactive care, and awareness of risk factors can go a long way in preventing sheared skin and associated complications.
FAQs
How to Avoid Skin Shearing?
Avoiding skin shearing requires proper seating materials, the use of pressure-relieving cushions, and maintaining correct posture. Tilt-in-space seating systems can help redistribute pressure and prevent downward sliding. Regular repositioning and the use of low-friction fabrics also play a crucial role in preventing skin shear.
What Causes Shearing of the Skin?
Shearing occurs when the skin remains stationary while deeper tissues shift due to pressure and movement. This is often caused by poor posture, sliding in a chair, or friction from improper support surfaces. Bony prominences are particularly at risk for shearing injuries.
How to Prevent Shearing of the Skin?
Preventing skin shear involves a combination of factors, including using friction-reducing fabrics, implementing tilt-in-space seating, selecting pressure-redistributing cushions, and ensuring frequent movement and repositioning. Regular skin inspections can help detect early signs of shearing injuries before they become serious concerns.
Ralph has many years' experience in the healthcare sector. In a previous life he worked in finance, and his spreadsheet skills come in handy for all the analysis and research he does as he investigates topics and solutions for some of the world's most complex healthcare conditions and challenges. Aside from writing in-depth articles and organising webinars and interviews with top healthcare professionals, Ralph also administrates Vivid's "Healthcare Pioneers Board", a large group of healthcare specialists with multiple disciplines, who are working together to improve care for years to come.
