This invention relates to implants formed from donor bone for use in lumbar interbody fusion procedures and instruments for performing such procedures. The built-in type compressorcondenser unit includes a louver frame installed on a rectangular shaped space formed on an outer wall of a building. The rapid, intense heating of the ceramicmetalceramic sandwiches using the defocused laser beam results in diffusive conversion of the refractory metal foil into the ceramic and in turn creates a strong bond therein.