Ventriculoperitoneal shunt failure from spontaneous knotting of the peritoneal catheter

At the time of surgery, the ventricular portion of the catheter was disconnected from the valve. Good flow of cerebrospinal fluid was seen, suggesting a properly functioning ventricular catheter. The peritoneal portion of the shunt was disconnected from the valve and tested, showing no flow through the peritoneal end of the catheter. For this reason, the entire shunt was replaced. When the peritoneal end of the shunt was removed from the abdomen, it was found to be doubly knotted (Figure 1), which was the likely cause of the shunt's failure. Because there was no evidence of knotting at the time of first insertion, we hypothesize that the normal peristaltic movements of the bowel caused the catheter to knot. We do not routinely perform imaging for shunts after insertion, so we could not determine exactly when the shunt knotted.1 It is possible that the shunt was inadvertently loosely knotted at the time of insertion. Following shunt replacement, the child returned to her baseline level of functioning.