Bob VogelQ. I’m a T8 Para, 15 years post-injury. My handcycling friends are giving me a hard time because I haven’t replaced my cushion in eight years. I check my skin from time to time and it looks fine. If I do decide to replace it, how do I go about it, and what should I look for?
— Curt

A. Every cushion has a finite lifespan. Eventually, every brand, make and model will wear out and break down, and the cushion will no longer support and protect your skin the way it was designed to, putting you at risk of a pressure sore. It is vital to replace your cushion before this happens.

Your question is timely because a study published in a recent issue of Journal of Tissue Viability used “finite element” computer modeling to measure and compare the effectiveness of two common types of cushions: foam-based and air cell-based. The results provide important clinical data to look at when choosing a cushion. It also found that deep-tissue injury — a serious type of pressure ulcer that starts below skin level and is not visible until it opens up