Catheter position rating scale. Grade I: ideal catheter position with contact to the ventricular wall less than 0.5 cm. Grade Ib: contact to the medial and lateral ventricular wall in the case of ventricular width equals the catheter diameter. Grade II: contact to the ventricular wall or the choroid plexus of more than 0.5 cm. Grade III: only partial intraventricular position of the catheter (less than 1.5 cm intraventricular). Grade IV: extraventricular position of the catheter (less than 0.5 cm intraventricular).