Conference 7.286::space

854.0. "Shuttle tile material may help in bone transplants" by PRAGMA::GRIFFIN (Dave Griffin) Thu Jun 03 1993 10:28

Charles Redmond
Headquarters, Washington, D.C.                         June 2, 1993

Jane Hutchison
Ames Research Center, Mountain View, Calif.



RELEASE:  93-102


     The same material that keeps the Space Shuttle from burning up when it
returns from space may be useful in treating medical problems on Earth.

     Researchers from NASA's Ames Research Center, Mountain View, Calif., are
working with physicians from BioMedical Enterprises Inc. and the University of
Texas Health Science Center, both of San Antonio, to determine whether the
Space Shuttle's ceramic surface insulation materials can be used as an implant
for human skeletal reconstruction.

     "We're still a long way from having a bone implant that's ready for human
use," said Howard Goldstein, Senior Staff Scientist in Ames' Thermosciences
Division. "But we have data that show the tile material has excellent promise
for use as a bone implant."

     Goldstein led the research, development and evaluation of the ceramic,
known as Reusable Surface Insulation (RSI), in the 1970s and 1980s.  He also
will lead Ames' RSI research team on the new project.

     Tiles made of RSI cover the Space Shuttle and keep it from burning up when
it re-enters Earth's atmosphere. "The theoretical attraction of Shuttle
insulation is that it is biocompatible," said Dr. Dani Goldwater, Manager of
commercial space programs at Ames. "It also provides a porous framework, which
allows infiltration by normal bone cells and deposition of bone mineral.  The
result could be complete integration of the implant into normal bone," she
said.

     Goldstein cautioned, however, that "a lot remains to be done before we can
demonstrate the many potential uses of RSI as a bone implant." For example,
scientists must improve the material properties of the ceramic fiber composite.
They also will have to increase the pore size of the material for use as a bone
scaffolding, while increasing its strength and maintaining biocompatibility.

     Dr.  Casey Fox, BioMedical Enterprises Inc., and Dr. Thomas Aufdemorte,
University of Texas Health Science Center, first must determine the safety,
efficiency and applications for these materials as bone implants.  After
developing and testing the product in the laboratory, they will work to get
U.S. Food and Drug

Administration approval for use in humans.  Fox expects the development,
testing and market approval process to take about 6 years.

     If tests are successful, "the ultimate result of this research might be
the production of implants that can substitute for or supplement natural bone,"
Fox said. "The contribution to the relief of human suffering is potentially
enormous."

     Fox said physicians perform between 1.2 million and 1.7 million orthopedic
and dental procedures each year that could benefit from the availability of the
bone implant material.  People with bone disorders resulting from trauma,
disease and degenerative skeletal changes associated with aging are likely to
benefit from successful development of this bone implant, he said.

     "The successful development of RSI technology as a bone implant material
could lead to major improvements in the initial and long-term viability of bone
implants," Fox said.  He expects the new bone implant to be used with implants
such as metal pins, wires, plates and screws when treating a fracture.
Physicians also may use it instead of bone transplanted from humans, thereby
preventing disease transmission.

     "After healing within and around the porous implant, the result could be a
fiber-reinforced bone," Fox said.  In addition, he expects the porosity and
surface chemistry of the ceramic material to allow administration of medicines
that promote bone healing.

     RSI is a silica, alumina fiber and borosilicate glass composite that can
be adapted to mimic the structure of bone.  Dr. Daniel Leiser, assistant chief
of Ames' Thermal Protection Materials Branch, will lead Ames' effort to refine
RSI for the bone implant study.  The goal is to produce a high-purity, large
porosity, low-density, high-strength ceramic fiber composite.

     "This research team combines the unique talents of three groups,"
Goldstein said. "The skills of Ames' Thermosciences Division in developing
composites and processes will join with university-based clinical medical
expertise and the biomaterials and implant design skills of private industry."

     Ames scientists will develop processing methods to produce ceramics that
meet the requirements for pore size, strength and

biocompatibility.  Fox and Aufdemorte will study the performance of ceramic
materials as implants in the laboratory, which may include experiments on
future Space Shuttle flights.  They have shown that RSI materials appear to be
biocompatible and potentially useful for oral and general skeletal trauma and
reconstructive treatment.