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Think for a moment about seating discomfort – from a hard park bench to a firm wheelchair cushion. Typically, it's not that your entire rear hurts, just specific points, commonly called pressure points. Our rears aren't flat surfaces, so any time that we sit on a non-conforming surface – as with placing the bony protuberances of our rears on a hard, flat surface – pressure points occur, causing discomfort at best, skin breakdown and pressure sores at worst.

To address seating comfort and skin protection, wheelchair cushions are commonly available with some form of “immersion.” For example, on an air-filled cushion, while it initially looks like a flat surface, when one sits on it, it conforms to one's body, where bony protuberances sink in to the cushion, minimizing pressure points. Similarly, foam and gel cushions also work on the principal of immersion. However, off-the-shelf “immersion” cushions have limitations, unable to support one's weight entirely evenly over all contact areas. Further, off-the-shelf cushions lack dramatic positioning possibilities, limited in form. Nevertheless, off-the-shelf cushions serve a wide range of users who don't need dramatic pressure relief or extensively controlled positioning.

While typical “immersion” cushions serve many wheelchair users well, those with exceptional seating needs benefit from what's called custom “molded” seating. Truly, the ideal seating surface would be one that exactly replicates every contour of your rear, equally supporting every centimeter of your form. And, this is exactly what custom molded seating accomplishes – it replicates your anatomy as closely as possible, optimally distributing your weight, serving as a second skin of sorts. What's more, because molded seating conforms so closely to one's form, it allows for dramatic stabilization where one needs it, increasing overall balance and functionality.

Replication is Key
Molded seating is a one-off, custom art form, practiced by highly-skill seating specialists, and begins in a very logical way – that is, by taking a mold of the user's rear. There are several types of “seating simulators” that capture one's form; however, most commonly one is seated onto a temporarily-conforming surface – as with a bag full of tiny beads – which is worked to get an imprint of the user's rear. Additionally, the conforming surface allows the practitioner to build up positioning aspects like adductors and abductors for leg positioning.

How it's Done
The actual molding process begins with a mat examination by the clinician, fully understanding one's physical characteristics, including defining bony protuberances, skeletal alignment, asymmetries, and range of motion. Next, one is placed on the seating simulator, an adjustable seat frame with the molding bags (though, some molding bags can be placed directly in one's wheelchair for fitting). The clinician then forms the molding bags to one's anatomy, building up support areas and contouring surfaces where needed. Once the molding bags are formed, they are locked into position, either by vacuum suction or a hardening agent. The molded shape is then transferred to a negative mold by covering it in plaster to create a casting, or by digitally scanning it and transferring it to a 3D computer model.

Once the mold fitting is complete, the captured mold imprint is sent the custom cushion manufacturer who creates the cushion, typically carving it from a block of foam or made from a cast. From there, the cushion is sealed, and a cover is made. With the cushion complete, it's returned to the seating specialist for final fitting and placement with the user.

All in the Details
As one might suppose, custom molded cushions are costly, running upwards of $2,000 for a seat and backrest combination. However, for those in need, custom molded cushions are covered by many insurances.

A couple of caveats regarding custom molded cushions is that they are only as good as the clinician making them, and they're not suitable for all types of conditions (namely, those with dynamic, ever-changing positioning, or who experience variations in weight). Therefore, finding the right clinician and having a proper assessment are vital to considering a custom molded cushion.

If only our rears were flat, we could sit on a hard seat pan, with our weight optimally distributed. However, as uniquely shaped individuals, our rears are round, lumpy, bumpy, and curvy. If you find that off-the-shelf wheelchair seat cushions don't fit your round, lumpy, bumpy, and curvy rear, you may be just the candidate for a custom molded seat cushion, one that doesn't fit like a glove, but even better – it fits like second skin.  

Published 11/08, Copyright 2008, WheelchairJunkie.com