Wednesday, May 23, 2012

A Different Type of High Tech

In the closing days of 1999, December 30th, Mrs. Graybeard and I were out for a bike ride as we had been perhaps a thousand days before.  It was very nice day weather wise; clear skies, light breeze, and  temperatures in the mid-50s.  There's a reason that's tourist season around here; people want to come here for the weather.

This particular ride was going to turn out to be a rather bad one.  About five miles from home, on a not-particularly busy road, we were run down from behind by a small pickup truck.  The driver, a young woman, had dropped something, taken her eyes off the road, and drifted out of her lane.  Our bikes were totaled, I shattered the little truck's windshield and was bounced onto the grassy shoulder; my wife ended up in the road.  To shorten the story, I was extremely lucky; my wife, less so.  I walked out of the hospital emergency room around four hours later.  She required massive surgery and was hospitalized for three weeks.  I had a broken tail bone, and a cracked vertebra (L1).  Her L1 vertebra was crushed, not just cracked, and required transplant of donor bone, stainless hardware, and growing bone around implanted hardware.  It was a four or five hour surgery, with a general surgeon involved to get access to front of the destroyed vertebra, and implantation of the donor bone (a section through a femur, actually); then opening her up through the back to add all the hardware to stabilize the injury. 
(source) A "typical" lumbar vertebra. The round portion had been pulverized and was replaced with donated bone.

This is one reason for my interest in high-tech medicine.  Design News this week reports on a new substrate for growing new bone in cases where bone is severely damaged or destroyed. The technique uses fibers of silk as the substrate to grow new bone upon.  This could potentially replace the piece of donated thigh bone implanted as replacement for the damaged body of the vertebra, but seems likely to replace a sort of mortar made from ground bone used to help the hardware fuse into place.  Donated bone brings with it the potential for infection and other problems if it is not well sterilized.  This approach could allow the factory growth of bone for such emergencies. 
The silk microfiber-protein composite matrices mimic the mechanical features of native bone. These include the stiffness of bone's interior matrix and the surface roughness that enable differentiation of human mesenchymal stem cells from bone marrow to achieve bone formation. The team found that, combined with the inherent strength of silk fibers, the compressive properties inside the scaffolds were enhanced by the structure's compact fiber reinforcement.
By the way, did you notice that we both broke L1?  It turns out to be a common fracture in cyclists that get run down. 

Years ago, a co-worker who is a bit more of a sci-fi geek than I am, asked if I'd like to live forever.  Medical science would have to advance a lot more before I'd like to start down that road.  Here we are 12 years out from that accident, and I get a numb-to-painful feeling in my left thigh if I stand for more than a few minutes.  Walking isn't that bad, and can make the problem go away, but it's gradually getting worse and I don't know of a real treatment for this.  Living a long time wouldn't be bad if everyday didn't bring increasing pains.

I rush to add that I have little to complain about.  When I see folks returning from the sandbox missing arms and legs, the knowledge I have nothing to complain about gets reinforced.  Although I have a garage full of tools that will take off a finger without slowing down, I still have all 10 fingers - at the proper lengths.  Still, I have a dream.  My dream is that the emerging art of tissue engineering allows the regrowth of lost parts, and the healing of damaged ones.  People who have lost a limb should have a new one grown for them.  People with diabetes who have a non-working pancreas should have a new one grown.  Arthritis?  Grow new cartilage.  Lost your colon or bladder, liver or anything else due to cancer?  Grow a new one.  Then it would be more tempting to stick around and live on. 

2 comments:

RegT said...

While a student at UCSD back in the mid '70's, I had a work-study job at Salk Institute in La Jolla, CA. One of the researchers was studying regeneration in the neuro-endocrinology lab. My job was caring for the Mexican axolotls he used in his research.

I never followed up to see what might have been developed from his studies there, but it was certainly interesting seeing the re-growth that took place with those large newts when a limb was removed. Seemed like magic, at the time.

As someone who has also sustained back injury (L3 through S1), I can sympathize. The lateral (outside) area of my left thigh used to be numb (yet with occasional "electric" tingles) almost all of the time. With a good chiropractor (hard to find) and a good physical therapist (easier to find), I now have most of my sensation back in that area. Daily exercises and a couple of non-narcotic meds help keep it that way.

Graybeard said...

That's it exactly, lateral area of my left thigh. When Mrs. G went into the rehab hospital, a week after surgery, they gave her a notebook with a map that showed the areas on the body that might trouble you depending on the area of the spine that was injured. The L1 injury corresponded to the lateral thighs. Also the top of my left foot from the S1/tailbone fracture. My foot hardly bothers me at all. I gotta say the tailbone hurt much more at the time of the injury - it was tough to sit on most chairs for a good 8 or 9 months.