NOVEL MATERIAL FOR SPINALIMPLANTSBMDO HISTORYUltramet (Pacoima, CA) received SBIR funding from BMDO to develop insulatormaterials <strong>for</strong> rocket nozzles. From this research, the company successfullymanufactured synthetic cellular foams that can serve both as insulatorsand as kinetic energy absorbers. The foams are made of ceramic, metal, and glassand can be used <strong>for</strong> <strong>biomedical</strong>, environmental, and construction <strong>applications</strong>.• Ultramet’s synthetic cellular materialsare readily compatible with natural bone.In evolutionary terms,the human spine is animperfect support systembecause of our fairlyrecent adaptation to theupright position. It wasreally designed <strong>for</strong> creatureswho move on allfours. Back pain andspinal disorders areprevalent in human lives,largely because of thisengineering glitch.HOW IT WORKSUltramet’s materials are composed of a carbonfoam skeleton that is treated by a chemicalvapor deposition (CVD) method to laydown a coating of various compounds andelements. Through CVD, a continuous thinfilm of metals such as rhenium or tantalum,or compounds such as silicon carbide, canbe distributed throughout the interior of theconstruct, lending certain thermal or tensileproperties to the carbon foam substrate andto the structure as a whole. The resultingproducts are characterized by low cost, lowdensity, high chemical purity, controlledthermal expansion, and high thermal stability.Depending on the coating used, the materialcan be made resistant to oxidation andcan withstand temperatures of up to 6,000°F. The high strength and porous structure ofone Ultramet product, Hedrocel ® , makes itespecially useful as a biocompatible replacement<strong>for</strong> the vertebral bodies that make upthe spinal column. Hedrocel is a tantalumcoatedcarbon porous matrix product thatmimics the properties of, and is compatiblewith, bone.74MEDICAL SIGNIFICANCEThe problems of the aging spine can be traced, at times, to loss of soft tissuebetween the vertebrae. This can lead to pain from compressed spinalnerves. Cancer that has metastasized to the spine, degenerative diseasessuch as arthritis, and trauma can also compromise soft tissue. Hedrocelwas licensed by Implex Corporation (Allendale, NJ) to be used in replacementdiscs <strong>for</strong> the spinal column. Specifically, the replacement acts as aspacer in support of the vertebral body, or the round portion of the disc.The porous natural structure of bone is simulated by Hedrocel, and bonecan gradually infiltrate into the artificial disc just as it would into a dam-Chapter 3 - Intervention TechnologiesSection A - ImplantsBMDO Technologies <strong>for</strong> Biomedical Applications
aged section of natural bone. The vertebral body implant is screwed intoplace, sometimes with a cement accompaniment, and consolidation takesplace as the bone and Hedrocel implant fuse together. The fusion obviatesthe necessity <strong>for</strong> the soft tissue disc, and the two bony processes growtogether, reducing the possibility of nerve compression and there<strong>for</strong>e pain.VENTURES OR PRODUCT AVAILABILITYEarly animal studies funded by the National Institutes of Health spurredImplex to build facilities specifically <strong>for</strong> Hedrocel implant products.Hedrocel vertebral implants were then used in eight European patients inlate 1994. They are currently being used in a United Kingdom trial of 25patients, specifically <strong>for</strong> replacement of the lower cervical vertebrae.Implex is also planning to manufacture devices <strong>for</strong> the small joints of thefingers, as well as components <strong>for</strong> hip replacements.Ultramet owns the patent on the carbon foam process. Ultramet licensedthe technology to Implex, which trademarked Hedrocel.CONTACTUltramet, Inc.Robert H. Tuffias, Ph.D.12173 Montague StreetPacoima, CA 91331Telephone: (818) 899-0236Facsimile: (818) 890-1946Email: ultramet@earthlink.comWWW: http://www.ultramet.com75BMDO Technologies <strong>for</strong> Biomedical ApplicationsChapter 3 - Intervention TechnologiesSection A - Implants
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