Experiences with recurring ventricular catheter obstructions.

Seven cases are presented of recurrent ventricular catheter obstruction, an infrequent but serious problem in the management of hydrocephalus. Plugging of the catheter was caused by detritus rather than by choroid plexus. A retrospective analysis of 214 shunt revisions indicated that obstruction both by detritus and by choroid plexus were incidental phenomena in the great majority of the cases - the former type occurring mainly within the first month, the latter between 3 and 6 months after operation. It is suggested that the ultimate cause of recurrent catheter obstruction by detritus may be destruction or ablation of the ependymal lining of the ventricles (e.g. by an inflammatory process), which easily provides debris to the catheter. In 4 of the cases insertion of the catheter into the opposite ventricle prevented further recurrence, when reinsertion into the same ventricle had been ineffective. In one case, with scarcely dilated ventricles, external decompression was helpful. In patients with compartmentalisation of the ventricles (substantiated in one of our patients) one might consider removal of the septa via craniotomy before the insertion of the catheter.