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Technology Stocks : 3-d Systems (TDSC)
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To: IngotWeTrust who wrote (123)5/31/1998 4:13:00 PM
From: Roger Lagerquist  Read Replies (2) of 132
 
Funny you should mention hip implants.
I worked from 1978 to 1992 designing and manufacturing hip implants, custom silicone implants, intraocular lens implants and surgical tools. Stereolithography didn't become available until late in that period.

In the early 1980s we made custom silicone implants from plaster casts of patients' trauma. Surfboard technology yielded polyester positives of missing bone and tissue. Hand labor shaped the polyester into masters for molds to make silicone components. Many of the prostheses were composites of tough bone-like silicone and soft tissue-like silicone. Computer modeling and stereolithography would have made our lives MUCH easier.

Your comment regarding custom hip replacements is intriguing. Near-insurmountable obstacles (regulatory, not technical) face anyone who tries to get into that business. The FDA has taken all the fun out of medical device manufacturing. I'd be interested in finding out more about people who are using TDSC technology to produce prostheses. It seems like a natural application. The TDSC annual report hints at some terrific applications based on CAT scans of a patient.

As far as I know, hip implantation is still done by sawing off the bone, reaming it out to fit the nearest standard implant and hammering/cementing the implant into place. By the way, we used a cast cobalt alloy with carbon-loaded Teflon bearing surfaces. Stainless steel was vulnerable to attack by the body's enzymes. Strength requirements are surprisingly demanding.

As I mentioned in a previous post, I've never been exposed to Stratasys's products, nor do I know the history of TDSC's new material. The work done by TDSC machines has always been impressive, and it keeps getting better!
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