Microscopic studies in shunts for hydrocephalus.

Valve-regulated systems, used for the treatment of hydrocephalus, were studied with the scanning electron microscope. The study was performed on unused systems of shunt replaced after different pathologies and on systems removed due to cerebrospinal fluid infection. Defects in the material, such as holes and protrusions, were systematically found in new systems. Aged shunts (1--8 years of implantation) as well as those removed in cases of cerebrospinal fluid infections showed important changes in the structure of the material too; it was also found that biological material, such as fibrin, red blood cells and bacteria, were able to adhere to the walls of the catheter tubing. These results indicate that the scanning electron microscope could be a complementary tool to be used in research, diagnosis, and quality control of silicone rubber prosthesis.