A sensing and drainage catheter for use in a cranial site includes a reduced diameter connector so that traditional tunneling techniques may be used with the connector-equipped proximal end of the catheter, rather than the sensor-equipped distal end of the catheter. The catheter includes a drainage lumen and a signal conducting lumen. The signal conducting lumen including a distal sensor for sensing the properties of cerebral spinal fluid and means for transmitting data signals representing those properties in either optical or electrical form to a reduced diameter connector attached to the proximal end of the lumen. A method comprises first accurately locating the distal end of the ventricular catheter in the brain ventricle prior to the catheter being tunneled under the scalp. The connector end of the catheter is then tunneled or threaded through a subdermal tunnel, and is then coupled to a counterpart connector for communication of the sensor signals to a monitor, and the drainage lumen is coupled to a bag for receiving excess CSF.