Biodegradation of distal shunt catheters

In a review of pediatric and adult distal cerebrospinal fluid shunt failures, the distal catheters were found to have deteriorated to the point of malfunction in 7 individuals after intervals of over 7 years. All 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 was assessed by radionuclide shuntogram study and at surgery. Degradation of catheter material led to irregular attenuation and fracture of the catheter wall with diffuse leakage of radionuclide into surrounding tissues. The catheter length of most chronic duration following implant was inevitably affected. Radionuclide shuntogram study of the distal catheter clearly identified the nature of the problem by showing an irregular outline of the catheter lumen due to spread of radioactivity into the surrounding soft tissues. Occasionally, intense foci of activity were identified at single or multiple sites where the catheter wall was grossly attenuated or fractured, resulting in cessation of catheter flow further distally. The biodegradability of distal shunt catheters leading to malfunction must be considered when assessing a young individual with features of hydrocephalus and a chronically implanted catheter length. Radionuclide shuntogram study is a convenient means of assessing the problem.