In order to answer that question, we should first talk a little bit about kyphosis in general. Technically, the term we want to use here is hyperkyphosis, ‘Kyphosis’ simply refers to ‘the amount to which the upper part of the spine curves forward.’ Everyone has kyphosis; if you don’t and your spine is instead straight or curves backwards toward the top, you have an insanely rare condition called hypokyphosis that has its own entirely different set of problems.
If you have hyperkyphosis, it can cause some pretty severe pain as well as looking fairly odd to strangers. There are five basic kinds of hyperkyphosis:
- ‘Dowager’s Hump,’ or ‘postural kyphosis,’ simply means that you’ve slumped forward for so long that your muscles and tendons no longer hold your shoulders and head as straight as they’re supposed to. In extreme cases, this can actually cause your vertebrae to fracture — or, oddly, can be caused by fractured vertebrae.
- ‘Hunchback,’ which can be either ‘gibbous deformity’ or ‘Scheuermann’s kyphosis,’ happens when one side of a few adjacent vertebrae die, causing what’s left of each to become wedge-shaped. The result is a sharp downward bend where most people have a very gentle forward curve. It’s quite painful at the apex of the curve and can severely curtail motion.
- ‘Congenital kyphosis‘ is a catch-all term for anything that happens during the formation of a baby’s body that causes the spine to bend too far forward. It can be as mild as postural kyphosis or as severe as hunchback, with effects that vary based on the degree of the curve.
- ‘Post-traumatic kyphosis‘ is a catch-all term for anything that happens after birth that causes the spine to bend too far forward — almost always some form of severe spinal trauma like getting hit by a car.
- ‘Nutritional kyphosis‘ happens when a child cannot eat properly while their bones are growing, and thus the bones do not develop with enough strength to support the weight of the arms, shoulders, and head. The most common cause of nutritional kyphosis is rickets (vitamin D deficiency.)
What Does This Have to Do With Chairs?
Simply put, if you have a severe form of kyphosis, you need a different chair than you do if your kyphosis is mild. The best chair for kyphosis of the more mild variety is relatively straightforward: you need an office chair that will offer your lumbar spine very solid support, even when you aren’t sitting “properly”. A chair with a Dynamic Counterbalancing system that moves with you as you lean forward and back is ideal.
For severe kyphosis, a chair should have two elements: first, the seat pan and seat back should both be tilted backward, so you sit with your spine at a slight angle and resting on the seat back. Second, it should also have a Dynamic Counterbalancing system, but that system should be configured to disallow you from leaning forward and tilting you seat pan forward at the same time, or you’ll risk spilling out of your chair. Essentially, the same chair as for mild kyphosis, but with some unique modifications to take your condition into account.