Image-guided placement of ventricular shunt catheter.

The position of the ventricular shunt catheter is by far most important factor in the long-term patency of a cerebrospinal fluid shunt. However, standard technique, which relies on surface anatomic landmarks and the surgeon's sense of spatial orientation, is not consistently accurate in the positioning the ventricular shunt catheter. Image guidance provides not only a three-dimensional reconstruction of the ventricular system, but also a real-time virtual trajectory for the catheterization. The authors, using a neuronavigation system, describe the ideal trajectory and target for accurate placement of a ventricular shunt catheter. Seventeen consecutive trials of image-guided placement of the ventricular shunt catheter resulted in excellent positioning of the catheter, within the free cerebrospinal fluid space just anterior to the foramen of Monro. This positioning was accurate in each case, even if the ventricles were distorted or shifted.