BIODEGRADATION OF DISTAL SHUNT CATHETERS

In a review of pediatric and adult distal cerebrospinal fluid shunt fa ilures, the distal catheters were found to have deteriorated to the po int of malfunction in 7 individuals after intervals of over 7 years. A ll cases presented in the first two decades of life with a duration of symptoms ranging from 1 to 62 days. The mechanism of shunt failure wa s assessed by radionuclide shuntogram study and at surgery. Degradatio n of catheter material led to irregular attenuation and fracture of th e catheter wall with diffuse leakage of radionuclide into surrounding tissues. The catheter length of most chronic duration following implan t was inevitably affected. Radionuclide shuntogram study of the distal catheter clearly identified the nature of the problem by showing an i rregular outline of the catheter lumen due to spread of radioactivity into the surrounding soft tissues. Occasionally, intense foci of activ ity were identified at single or multiple sites where the catheter wal l was grossly attenuated or fractured, resulting in cessation of cathe ter flow further distally. The biodegradability of distal shunt cathet ers leading to malfunction must be considered when assessing a young i ndividual with features of hydrocephalus and a chronically implanted c atheter length. Radionuclide shuntogram study is a convenient means of assessing the problem.