by Kirsten N. Davin, OTDR/L, ATP, SMS
Today, there are an estimated 3.3 million wheelchair users in the United States, and as the Baby Boomer population continues to grow, the number of wheelchair users is on the rise as well. Some estimate as many as one-third of wheelchair users lack adequate trunk control to safely and effectively perform functional tasks from wheelchair level, thus necessitating the need for anterior trunk support application. Anterior trunk supports are designed to provide support for the torso, in order to improve the client’s positioning within the seating system as well as enhance overall function from wheelchair level, thus offering clients of varying levels of trunk instability the opportunity to be as independent as possible within their daily lives.
If one reflects back to their initial education about wheelchair seating and positioning, the foundational concept, “proximal stability results in distal mobility,” may come to mind. If we extrapolate this concept to the performance of activities of daily living, the self-propulsion of a manual wheelchair, or the successful use of head array systems or power wheelchair controls, one quickly understands how important successful torso support becomes; for without strong proximal stabilization, one’s distal mobility, and subsequently, functional performance and independence, suffers. This proximal stability must begin at the pelvis, with appropriate and stable pelvic positioning, which may be achieved via the use of contoured seating cushions, pelvic belts, hip guides, or other custom pelvic stabilization methods. Start at the pelvis and move to the torso for continued stabilization to ensure greater success with distal function.
In addition to the benefits of improved positioning and distal function, clients who require the use of anterior supports will experience a number of physiological benefits, such as greater lung capacity as a result of reducing or eliminating a forward-flexed posture which compresses the respiratory system. Improved swallowing and reduced aspiration risk are also benefits, as well as a notable improvement in digestive, bladder, and bowel function, all of which are derived from torso neutrality due to the use of various kinds of anterior supports.
Plenty of manufacturers offer an assortment of anterior support designs and styles, but to provide the client with the most appropriate support for his or her diagnosis and presentation, it is imperative that the clinician have a strong knowledge base in the architecture of the support options available.
Anterior Trunk Support Cut Styles: Standard Cut Versus Slim Cut
A standard cut anterior support provides a uniform fit to the user while offering increased surface area and pressure distribution to the torso. Frequently recommended, this style of anterior support offers the user a more aggressive and supportive, full-torso hold as opposed to other cuts. Although beneficial due to its all-encompassing design, this style is not conducive with clients who present with abdominal ports, feeding tubes, or similar devices, as the anterior support placed over the device may not be indicated.
The slim cut design, which utilizes significantly less material, resulting in far less surface area coverage compared to the standard cut, is often used with clients who present with breast cancer or status post-mastectomy. The medial aspect of this slim cut style of anterior support can be as narrow as 3 inches in width, thus avoiding breast tissue and providing the client with adequate support without full coverage. This cut is also beneficial for clients who present with radiation sites due to breast cancer, scar tissue, temperature regulation issues, or hyperhidrosis (excessive sweating).
Often, there are times when medical devices restrict the ability to apply a standard or slim cut design as noted above. In the event a client presents with a recent abdominal surgery, scar tissue, postsurgical abdominal drains, pregnancy, G-tube/feeding tube placement, or the presence of a colostomy, PEG tubes, or other devices which may render the client’s anterior torso, umbilical, and hypogastric regions unable to tolerate the pressure associated with the application of a standard cut anterior support, an H-Harness design style may be beneficial. This design, often referred to as a pivot-style or swivel-point design, is shorter in stature, thus allowing improved focus on supporting the torso and thoracic region with nearly complete abdominal clearance. The H-Harness can also be utilized for clients who present with increased adipose tissue to the abdomen, resulting in sizing and fitting challenges if a standard-cut support were utilized.
In the event a client presents with unilateral weakness or hemiparesis as a result of a stroke or neurological event, frequently, the weakened side of the torso will anteriorly rotate and flex forward. In order to address this specific positioning need, the Y-Style design may be implemented to either the left- or right-side shoulder and upper torso as appropriate. The Y-Style, often referred to as the Y-Harness, allows for greater range and dynamic movement of the unsecured shoulder, while offering anterior support via the single strap crossing the trunk. This design can be greatly beneficial for clients who are sport chair users or athletes who present with weakness to one side, yet require unrestrained range of motion to the unaffected side or for those who have a need to have their dominant extremity completely free at the shoulder for performance of higher-level activities of daily living, such as reaching into wall cabinets or washing clothes in a top-load washing machine.
This design is also beneficial for clients who present with rotational scoliosis in which the entire trunk presents in a rotated pattern, as the Y-Style specifically isolates and applies the posterior force required to neutralize the protracted side, in the case of a corrective or flexible asymmetry.
Chest Support Design
Often, clients prefer a less invasive, less cumbersome appearance in anterior support as compared to the standard-cut, which encompasses a much greater portion of the torso. For clients who prefer this sleeker appearance in torso support, while aiming to correct flexible asymmetries of the trunk, the chest support, in either a one- or two-piece design, will prove beneficial. In addition to the sleeker appearance, clients will benefit from the freedom of shoulder rotation and scapular mobility afforded by the positioning of the chest support, over the posterior trunk just below the axillary region, allowing them to more successfully perform activities of daily living, cooking, cleaning, laundry, child care, or other daily tasks.
Chest supports can be comprised of a one-piece or two-piece design, each of which offer its own benefits and liabilities. The one-piece design, comprised of a single strap crossing the anterior torso, just under the axillary region, can be applied and released via a buckle, located at the end of the strap, near the frame of the wheelchair. This release can be difficult for clients to access who present with fine motor or range of motion deficits, or generalized upper extremity weakness. In that case, the two-piece chest support may be beneficial as the release for this support is centrally located, near the sternal region, and comprised of a Velcro closure which is more easily accessed by clients with upper extremity weakness or fine motor limitations.
The common theme among all of the previously noted anterior trunk support designs lies in the fact that each has a component that crosses the client’s midline and sternal region. In most cases, this is a useful design and aids in thoroughly supporting the torso and stabilizing the core to improve distal function and the client’s independence. Unfortunately, although rare, there have been cases in which the client has experienced respiratory distress as a result of pelvic migration, in which the pelvis slides forward toward the front of the seating system, resulting in the client sliding downward in the wheelchair and the client’s neck resting dangerously upon the anterior trunk support.
This backpack design, often referred to as a shoulder retractor or shoulder harness, eliminates the risk of injury or respiratory distress as a result of the client sliding down into the seating system via pelvic migration, and offers a strong benefit to clients who present with recent or problematic sternal injuries, or excessive or hypersensitive breast tissue, as the backpack style will minimize the impact on the affected area(s). Cosmetically speaking, many clients prefer the backpack style of anterior support as the bilateral shoulder straps can be easily concealed underneath scarves or other apparel, thus rendering it more cosmetically friendly than other models.
Anterior Trunk Support Fabric Styles: Stretch Versus Non-Stretch Fabrics and Zippered Options
After determining the preferred cut or design of the chosen anterior trunk support, the healthcare professional must next consider the characteristics of the fabric to be utilized. Stretchable fabrics offer greater contact and better engulfment of the anterior support to the client, offering a full contact support, with all areas of the anterior support touching the client. This engulfment reduces the risk of pressure injury which can occur with a nonstretch fabric, as without a stretch feature, many anterior supports present with a high degree of pressure in one area of support and a buckling or noncontact area in another, thus creating unequal pressure and/or rubbing which may create pressure issues or skin breakdown.
Stretch fabrics also offer a more precise fit, along with even distribution of pressure and uniform anterior pressure being provided to the client’s torso, often helpful with clients who present with sensory integration diagnoses. Perhaps the most important aspect of the stretch fabric option is the degree of adjustability within their anterior support system. For example, clients who present with periods of hypertonicity (high tone) or writhing, athetoid movements while in the seating system often utilize the stretch design to elicit some accommodation and offer some movement within the seating system while the anterior torso support is in place. For clients who present with extraneous movements within the seating system, the stretch fabric will allow movement to ensure client safety and while simultaneously “following” the client back into the original position at the completion of the episode.
In a case where healthcare professionals want to ensure little to no movement within the seating system, commonly desired in diagnoses such as cerebral palsy to inhibit tone response, a nonstretch fabric may be used. The nonstretch design will provide adequate support, while inhibiting excessive motion within the seating system.
Similar to the two-piece chest harness in terms of removal, a zippered option will allow the client or caregiver to remove the anterior support from a centralized point as opposed to having to reach across the body to a release point near the frame. This zippered option is often preferred as clients can easily access egress from the system in a fashion which is similar to removing a coat.
Each of the products previously noted will aid in achieving the greatest degree of trunk stability for a client, as trunk and torso stability can be the determining factor between successful function in work, play, self care and self-propulsion, as a result of enhanced as distal mobility. One final consideration when employing the use of anterior supports, or any type of support which comes in direct contact with the skin, is the condition of the microclimate, the region between the client’s body surface and the support device. When utilizing any of the above trunk support options, it is often beneficial to incorporate a mesh or breathable fabric in order to allow as much airflow as possible. As evidenced by the architecture of the support, some designs lend themselves to greater breathability and improved microclimate, yet regardless of the design, it may be best to incorporate a breathable fabric whenever possible.
The foundational concept, “proximal stability results in distal mobility,” should always be considered throughout the process of seating and positioning assessment, intervention, and equipment implementation. Anterior trunk supports offer a wonderful mechanism to ensure trunk and torso stability in order to offer the client as much distal mobility and function as possible. RM
Kirsten N. Davin, OTDR/L, ATP, SMS, owner of Escape Mobility Solutions LLC, Pleasant Plains, Ill, specializes in the provision of wheelchair seating, positioning, and assistive technology. She is a clinical consultant for Adaptive Engineering Laboratories as well as Patterson Medical, and nationally known for her continuing education seminars via Vyne Education, formerly Cross Country Education. Davin has been an occupational therapist at Memorial Medical Center in Springfield, Ill, for 15 years, and is currently an adjunct faculty member, teaching anatomy/physiology at Lincoln Land Community College. She also was named VGM’s Home Medical Equipment – Woman of the Year for 2016. For more information, contact RehabEditor@medqor.com.