Factors affecting the accuracy of ventricular catheter placement.

Despite technological improvements, ventriculoperitoneal (VP) shunts are still often complicated by malfunction, predominantly with proximal catheter obstruction. There is evidence that accurate placement of the ventricular catheter is significantly related to shunt survival. To identify possible risk factors that might lead to suboptimal shunt placement, we retrospectively reviewed the demographic data and radiological scans of 141 patients who underwent a VP shunt operation from 2005 to 2008 at our institution. We developed and validated a novel scale to assess catheter placement. Almost half (47.9%) of the catheters were "excellently" placed with the entire tip located in the cerebrospinal fluid, and the position of 25% was considered "good". However, 26.8% were less than optimally placed ("poor", "fair" or "moderate"), with 8.5% ("poor") lying entirely outside the ventricular system. Statistical analysis demonstrated that the preoperative size of the ventricles and the age of the patient at shunt insertion were the most important predictors in determining the quality of ventricular catheter placement. Further studies are required to evaluate frameless stereotaxy in optimizing shunt placement in patients with smaller ventricles.