Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sandia microscaffolding fits perfectly in patient’s jaw

16.05.2003


Painless bone substitute could offer new era for surgeons



In an operating room in Carle Hospital in Urbana, Ill., on May 7, as scientists from the University of Illinois (UI) and Sandia National Laboratories watched, surgeon Michael Goldwasser fitted a highly unusual ceramic prosthetic device into the mouth of an elderly woman who had lost most of her teeth and along with it, much of the bone of her lower jaw.

The fitting operation was to determine whether the implant - created a thousand miles away at Sandia in Albuquerque - had been accurately designed, from its overall shape down to inclusion of a nerve groove.


"If it fit like a sock on a rooster, our method wouldn’t have worked," Goldwasser said.

Observers said it fit like a glove.

If approved by the Food and Drug Administration for in vivo testing, the scaffoldlike structure - a layered mesh stronger than bone, yet porous - would substitute for a portion of the mandible, or lower jaw, until healthy, newly grown bone and blood vessels could weave their way through it like vines through a garden lattice. A patent for the implant is pending.

The ceramic scaffolding would reduce the pain, recovery time, and chances of infection of those needing bone replacements in the jaw, as well as skull, spine, or other bony areas. Other benefits include avoidance of longer surgeries, more predictability of outcome, and lower health care costs.

The device is built mainly of hydroxyapatite, a material already approved by FDA for bodily implants, so approval of the new device could be swift.

The woman was reportedly pleased to be part of an experiment that might benefit humanity, because the quality of fit would determine whether scientists and doctors using computer programs, modern communications, and machines a thousands miles from each other could produce a prosthetic device that would fit seamlessly in a patient’s sensitive mouth - or, for that matter, skull or spinal vertebrae - without the manufacturers ever seeing the patient.

But because scientists have studied the device’s strength and permeability only in vitro (in the lab), the woman then had to endure the standard method of bone replacement, which by comparison seems almost medieval. This involves cutting a several-square-inch piece of bone from her pelvis, which is then power-sawn and drilled into the correct shape in the operating room, a process that takes about an hour and leaves the patient to endure a healing pelvis as well as a healing mouth.

"Surgeons and patients would love to eliminate both the bone retrieval and implant preparation processes," says Sandia scientist Joe Cesarano, whose team fashioned the new implant. "This test showed we can make artificial porous implants prior to surgery that will fit perfectly into the damaged region. The reconstructive procedure would then only require attaching the implant and closing the wound."

A short course on bone implants

A surgeon uses the patient’s own bone to minimize rejection by the body. Harvesting bone, however, creates new problems, says Goldwasser. Not only is a new area of patient discomfort created but the operation requires more time and anesthetics. These raise the risks of complications in the operation and in healing. "We could use cadaver bones," he says, "but then we face risks of rejection by the host and of possible transfer of disease."

The body may also dispose of the foreign bone prematurely by absorbing it.

"What we want," Goldwasser says, "is a method by which I can see a patient in Illinois, transmit X-ray information to someone who can make a substitute part that would have the porous properties that would allow bone to grow into it, yet be strong enough for normal function. Here, this would mean mastication and appearance."

With the aid of UI bioengineering professor Russ Jamison and graduate and Sandia summer student Jennifer Dellinger, who were experimenting with the growth of bone across porous surfaces and needed a more regularly porous substrate than those found in nature, he learned of a device at Sandia that could do the job.

The Sandia device

The Sandia patented process called Robocasting, led by Cesarano, was conceived and built to fashion defense components out of ceramics in a process that permitted manufacture of specialty parts in a way no ordinary mold or machining procedure could achieve. Situated on a truck, it could make replacement parts on a battlefield, instead of carrying millions of parts onto a site. It is also being developed to form advanced catalyst supports that operate like a maze (rather than straight channels) to increase chemical reactivity.

Controlled by a computer program, the machine dispenses liquefied ceramic pastes, like toothpaste squeezed from a tube, to form shapes of varying complexity along a prearranged path.

To create the simulated bone scaffolding, the machine dispensed a hydroxyapatite mixture in a child’s Lincoln Log-like arrangement, in cross-laid slivers each about as thick and as far apart as the diameters of ten human hairs.

"Bone, blood vessels, and collagen love to grow into a structure with pores of that size [500 microns]," says Cesarano. "The material becomes a hard-tissue scaffold for promoting new bone growth."

The trick in building it, he says, is that "the paste has to be strong enough as it’s being laid to set in place without under support."

Sandian John Stuecker made the paste thicker than normal by increasing the interparticle attractive forces. The changed procedure took about six months to master.

Finally, the scaffolds are embedded in wax and machined to exactly the right shape without splintering the hydroxyapatite. The wax is subsequently removed.

But what was that shape, and how was it to be determined?

The UIUC connection

In part, by the spark of an idea from Goldwasser and the diverse expertise linked together by Jamison.

"One by one, we linked together - even if only electronically at first - the people whom I knew who could bring talent, skill, and passion to the project. None of us working independently could have accomplished the results we have," he says.

Jamison involved computer technologists and designers Ben Grosser and Janet Sinn-Hanlon at UI’s Beckman Institute to encode CAT scan results into a computer program that could be shipped electronically to Sandia, where Michael Saavedra and David Gill created an interface to machine the final shape.

Complicating the process was that while a CAT scan could accurately delineate the diseased shape of an existing bone, it could not show what wasn’t there: the exact dimensions of what the bone would have looked like, were it healthy. This required the potentially expensive presence of the surgeon Goldwasser working with the computer programmers to create the dimensions of what should be there but wasn’t.

"Eventually, if it could be done electronically, it may be a very simple thing and cost-effective," he said.

"There is nothing inherently expensive about either the materials or the process," said Cesarano.

Using a CAD/CAM method where a surgeon need only sketch the shape needed, a piece might quickly and inexpensively take shape at a remote site.

"We’ll see if the clinician, the bioresearcher, and the engineer can come up with a method to implement it," Goldwasser said.


Sandia National Laboratories
A Department of Energy National Laboratory
Managed and Operated by Sandia Corporation
ALBUQUERQUE, NM
LIVERMORE, CA
MEDIA RELATIONS DEPARTMENT MS 0167
ALBUQUERQUE, NM 87185-0167
PHONE: (505) 844-8066 FAX: (505) 844-6367


Neal Singer | EurekAlert!
Further information:
http://www.sandia.gov/
http://www.sandia.gov/news-center/news-releases/2003/other/bone.html

More articles from Health and Medicine:

nachricht Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign

nachricht Rabies viruses reveal wiring in transparent brains
19.01.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>