View Full Version : Bad Back Design Considerations

11-16-2012, 09:58 PM
So I found out yesterday that I will be having 3 discs fused in my low back sometime next year. Most likely late spring or summer...

So, as I work out the design of my zombie, what experiences and wisdom can the folks with back problems point out to help me get this right the first time around?



11-16-2012, 10:17 PM
Hate to hear that Bill. I've no advise. Bad back is not one of the things I've had problems with. Hope it works out well for you and you come back stronger than ever.

11-16-2012, 11:15 PM
Thanks TT, unfortunately as my doc says, "at least you know you are not a product of the milk man..."

My dad just had his lower spine reconstructed last fall with cadaver bones, some sort of teflon rods, titanium pins and plates. My daughter had her first micro-discectomy last December at the age of 16, and I had my first one about 4 years ago so genetics just are not on my side. Plus while we were reviewing the films, it was easy to see that I have a disc narrowing in my upper spine right in-line with the bottom of my shoulder blades which explained a lot of new tightness I've been experiencing in my shoulders.

My main goal is to get Ethan's zombie finished for special olympics in the spring and then schedule the surgery probably for after that it just a question of timing.

11-17-2012, 12:12 AM
Best advise I can give you is talk to the Doc about what sort of restriction you'll have sitting or riding that is. I had heard from friends with this type of surgery that pain was no longer an issue and made it as if there was no issue except when walking through metal detector in the airports. Unfortunately or fortunately for me I should say is I don't have any first hand experience. But I though I would share what I have heard and wish you the best of luck in your surgery and hope it help you live a more normal life without pain.

11-17-2012, 07:53 PM
Sorry to hear about the back problem. My mother had three lumber vertibrae fused just after the war, and she manged quite well until the last cpouple of years, and she is now 92, so it is not the end of the world. She was told she would never walk again, but she could still me when I was 10 and needed catching!
Best advice is to talk to a doc that knows something about this, and about what you like to do, and try anything gently .
My guess would be that with careful seat design you will be peddling for a few years to come.
All the best,
Steve G,

11-17-2012, 11:22 PM
As a fellow sufferer of fused vertebrae, I can offer this:

Try to avoid the mesh seats. A padded plywood seat that is firm will feel better to you. You may have to adjust the seat/back angle a bit to find the most comfortable setting, but it can be done.

11-18-2012, 12:45 AM
Interesting Charlie, based on all those fancy mesh chairs I was assuming that the mesh seat method was going to be a better choice.

Recently I have been thinking about the seat design a lot more and my thoughts have been straying from the bent rail style to a hinged back design that would allow me to adjust the back angle separately from the seat bottom. I've also been looking at big bottom cruiser gel seats to use for the seat bottom, or incorporating wheelchair gel pads. The seat costs and complexity just went up for my seat, but you gotta do what you gotta do.

One other possibility though is that for my daughter's science egg drop project where you have drop the egg from 2 stories and have it survive, we found a recipe for home-made ballistics gel and used it to make a shell for the egg that not only saved the egg but got her extra credit for creativity, and I might try making a slab of it to see how it holds up to moisture after it cures and what kind of cushioning properties it has because it only costs a couple bucks to make.


11-18-2012, 08:39 AM
The ballistics gel does have some give to it when cured, so will probably be a good choice. a real plus to it is that you can form a mold to your own shape for maximum effect. I might have to look into doing that myself..... Making a seat with gel, you might have to cover it with a high wicking cloth to remove the inevitable sweat.

For mine, I have some 2.5" "egg crate" that was given to us. It has just enough solidity to support while softening the bumps and vibrations of bad roads.

For the curious, my fused vertebrae are L4, L5, S1. Nerve root damage in both (now non-existent) intra-vertebral spaces. Makes standing for long periods and bending over a bit of a challenge, especially with my extra -- shall we say -- frontal area (read big belly).

The problem I have with the mesh seats is that under tension from body weight, they become rather rigid, with very little "give" to them. Not much cushioning available. The up side of the mesh is that it allows air circulation for cooling. If we could come up with a seat design that incorporates both the gel and mesh......


Radical Brad
11-18-2012, 12:02 PM
I actually have a quirky back as well. Had an operation when I was younger that involved part of my lower spine coming through my skin.... yeah.... ouch!
I also find those mesh seats aggravate my problem, and the firm basic wood/foam seats to be better.

Seems that the term "ergonomic" is also mostly useless, especially in office furniture. I have tried so many chairs, and in the end I am back to a basic stool type with no arm rests. The "deluxe" ergonomic lumbar types seem comfortable at first, but after days of doing computer work I have problems. Last month I had so much pain, Kat dragged me to emerg. as I could not stand up for days.

I guess the game of comfort is an individual war. I tried out a few of those fancy curved recumbent seats with lumbar and found them intolerable.


11-18-2012, 02:43 PM
So, we have not gotten to the details yet, but my previous surgery was a complete removal of the disc at L5-S1. Actually the disc removed itself and injected itself into my spinal canal and compressed my spinal cord into a niche in my spinal column causing a spinal cord injury that leaves me in pain everyday and impact the use and muscle development of my right leg.

Right now, I think he is looking to fuse L2 through L5 or S1, I'm not sure how the previous surgery will affect this one...

Making a butt mold is an interesting. I know that I can get pieces of aluminum sheet cutoffs cheap from my local metal supplier and aluminum would make a much lighter base than plywood to offset the added weight of the gel. As well as having the advantage of being somewhat moldable itself which sounds appealing also.

I can't weld aluminum, but bolts should be fine to join the seat base to the frame that I make.

I'll have to do some research and see if there are some variations on the ballistics gel recipes out there to change the density after it has set.

As for a cover, I was thinking about getting some lycra from a fabric store and using some spray adhesive to fix it to the gel.

With your fusion, do you find that a cutout for lower lumbar region and coccyx is desireable?

11-18-2012, 03:04 PM
Thanks Brad. Can you give a few more details on your spine injury and location if you remember?

Historically I've always benefitted from lumbar supports in car seats and such, but in an office environment I'm more likely to work hunched forward and tend to be more concerned about lots of high quality seat cushioning.

Fortunately, because of my epilepsy issues (weird how that is fortunate...) I'm not working from home 100% and don't travel at all anymore, and our couch sort of like a sectional sofa that has one of those chaise seats at one end. My most comfortable seating position is in that chaise with a pillow under my knees, a pillow behind my low back and another pillow just behind my upper shoulders and neck which is why I've been thinking that something like what Spinner and River did would be beneficial but because of my extreme sensitivities, I need to make a better seat cushioning system and I need to be able to make the seat bottom and back independently adjustable so that I can fine tune the riding position, especially what is comfortable on Sunday morning might not be comfortable on Sunday afternoon...

Radical Brad
11-18-2012, 04:56 PM
I was 20 or so at the time. I set out on my enduro for an 8 hour journey down some very rough logging trails. The next day I was in serious pain and a lump began to form on my lower spine. It hurt so much I sat in the tub for hours at a time. A few days later a nasty sore began to form around the swelling and I finally went to the hospital. At this point, i was almost passing out from the pain and went right to x-ray. Seems there was a sharp bone abnormality on a disc that wore through the skin due to all of the bumps on the motocross ride. Had that removed, and it mainly healed, but I do have to watch it these days. The Doc did day it may come back to haunt me later on, and well.... it is now later on!


12-09-2012, 10:01 PM
I feel your pain.
I broke L4 and L5 in the 70's and have been in pain ever since.
I havnt had them fused but did have nerve blocks placed that worked for a few years.
I seriously cannot stress strongly enough that the most relief I received was by loosing the excess belly weight. No easy task but worth every second of the struggle for that final result, it was amazing how much pain just disappeared into thin air. (plus all the other benefits)
A thought upon the seat, make an airtight poly tube filled loosely with small styro beads. Set it an the angle you feel comfortable with for riding ensuring its long enough to reach up to your neck area.
Start sucking air out of the tube whilst you wriggle around to get the beads to conform to your back - butt - and shoulder area.
Remove ALL the air possible from the tube and seal it, this will set it rigid.
You now have a mold to produce a cast from. This first mold can be smoothed and flowed and cut to the main shape then used as the final mold to make the form fitting seat from glass fibre. Upholstered in memory foam.
A lot of work but you get a personal custom shaped seat that should be the most comfortable you could get.

12-09-2012, 11:54 PM
Thanks Savarin, that is an interesting idea. When I get to the seat I will definitely have look at this in more detail.