The process of the present invention provides for the manufacture of lower molecular weight DMC-catalyzed polyols than is possible using non-acidified continuous addition of starter feeds, by adding excess acid to a starter feed stream over that required for mere neutralization of the basicity of the starter. Devices and methods of the invention may be used to attach a bone engaging element such as a fastener to a spinal stabilization element such as a rod or a cord by bonding with a bonding material. The joint member made from resin envelops the portion where the inner edge of the edge frame and the edge of the shell body by casting manner.