To make the first injection molded head brace for accident victims, Sean Phillips employed some of the most sophisticated research tools he could find - including a saw, some plastic toys and a veterinary hospital X-ray machine.
Phillips, senior project manager with Laerdal Medical Corp. in Wappingers Falls, N.Y., wanted to build a better, cheaper brace for immobilizing the head, and he wanted to mold it from high density polyethylene.
But he had a problem. He could not find much data on how HDPE behaves in an X-ray machine, an important criterion because emergency room doctors often have to diagnose spinal injuries by X-raying patients without removing the head brace.
So he grabbed some HDPE toys - their odd shapes made them ideal for what he had in mind - and, acting a bit like a mad scientist with good intentions, Phillips cut them up and headed down to the animal hospital to X-ray them.
What emerged led to the X-ray-friendly, tapered wall design of Laerdal's SpeedBlocks head-immobilization device, an innovation that garnered the firm a silver award at the Medical Design Excellence Awards, presented June 5 at the Medical Design & Manufacturing East show in New York.
The annual award showcases new developments in medical product and packaging design, and this year's event featured several devices that judges said made interesting use of plastics. They include a biodegradable polymer used to grow replacement human skin, an intravenous bag that stores powder and fluid separately until they need to be mixed, and a miniature, plastic-encased camera that patients can swallow.
Using HDPE let Laerdal, for the first time, injection mold a head immobilizer for emergency situations, he said. It meets two of the main criteria in medical product design today - it reduces costs and it performs better, Phillips said.
``We principally chose the material because it's tough, has natural lubrication properties, is chemical-resistant and works in broad temperatures. And most importantly, it's inexpensive,'' he said.
The product costs about $50, about one-third the cost of other reusable braces, which are made of foam blocks dipped in vinyl, he said. Disposable cardboard immobilizers made by Laerdal cost about $5 each.
The injection molding also lets the company add an arch that leaves the ear uncovered so it's easier for paramedics to communicate with patients, said Andrew Serbinski, principal at MachineArt, a Hoboken, N.J., industrial design firm that helped develop the immobilizer. The molding is done by Promold Plastics in Cromwell, Conn.
Plastics also are key in the replacement human skin developed by Advanced Tissue Sciences.
It is the first time a company has made replacement skin entirely from human tissue, with no animal products mixed in. The biodegradable plastic is important because it functions as a matrix to hold the skin in place while it grows in preparation for being implanted, said Dawn Applegate, director of technology development at the company in La Jolla, Calif.
``The polymer is biodegradable so it goes away over time,'' she said. ``There is still some of the polymer matrix left when we put it on the body. We designed it that way because the skin is very fragile.''
The polymer is a blend of 10 percent polylactic acid and 90 percent polyglycolic acid, to provide both biodegradability and strength so doctors can work with it, she said.
``We want it to have some tensile strength, some handle-ability,'' she said.
The company uses a fiber, produced by Johnson & Johnson's Ethicon Inc. unit, that already has Food and Drug Administration approval for use inside the human body, she said.
Most cells will grow on many types of materials, including glass, plastic or metals, she said. In this application, the base product needs to allow a precise amount of open space within the polymer chain. It has to be close enough for the skin to stretch across, but porous enough so that it begins to grow in three dimensions, she said.
``What is absolutely critical is the pore size ... the size of the void space in the polymer,'' Applegate said. ``They have to be 100-200 microns apart.''
Advanced Tissue won a gold award in its category.
Another gold winner that was highlighted for plastics use by juror chair Eliot Lazar, president of Elcon Medical Consulting in Buffalo, N.Y., is a miniature camera and wireless transmitter that takes pictures of patients' small intestines.
The inch-long pill lets doctors see the entire inside of the small intestine, rather than just the upper or lower portions of it, as the current wire-based technologies allow, according to Sandra Smith Ziv, spokeswoman for Yoqneam, Israel-based Given Imaging Ltd.
Ziv said the company is tight-lipped about the details of its products, but the M2A Capsule had to meet some strict performance requirements.
``It had to be biocompatable, and not be affected by any digestive acids and mucosa,'' she said. ``One of the strictest tests with the FDA was to measure the weight to make sure that the capsule [was excreted] with 100 percent integrity.''
A gold award-winner that did not have intense biocompatability issues, but also caught the attention of the judges, was B. Braun Medical Inc.'s DuPlex drug-delivery system. The multilayer polyolefin bag had to overcome some technical hurdles that vexed Braun engineers for the better part of a decade, said Shari Sandberg, marketing director for pharmaceutical products in B. Braun's Irvine, Calif., office.
``The whole technical challenge with this is we are trying to package a drug powder that wants to behave like a desiccant and an oxygen scavenger right next to a plastic bag of water,'' she said.
Keeping the powder from absorbing the IV solution while the bag sat on the shelf was a problem.
The company came up with a multilayer design, including a layer of glass film and foil to protect the powder, and a foil layer to protect the solution, she said.
The manufacturing cost for the bag is higher than for traditional bags, but it saves labor because pharmacies do not have to mix the drugs themselves. It also cuts down on dosage errors and reduces drug waste in pharmacies, Sandberg said.
``In some institutions, drug waste is 5-10 percent of their drug costs,'' she said.