unit 24 similarly second catheter 32 can be tunneled from below up into the peritoneal cavity to serve as an outlet for the csf the tip of second catheter 32 is chosen to increase the flow of csf drainage and to reduce the likelihood of obstruction thereat in one embodiment the tip of catheter 32 is static having a conical shape with drainage ports along the surface and underside thereof in another embodiment the tip of catheter 32 is resiliently expandable for breaking up debris adhesions or other occlusions that can develop over time a suitable expandable tip is an appropriately modified angioplasty balloon which can be inflated to break up adhesions master control unit 24 is powered by a battery 36 or other self contained power source such as a high capacity battery such as already widely used in pacemakers stimulators defibrillators and the like it is presently preferred that battery 36 be located external to master control unit 24 and inserted in subcutaneous tissue to provide easy access for replacement in the event of failure it is also contemplated however that battery 36 could be integrally housed within master control unit 24 master control unit 24 is also characterized by a first access port 40 and a second access port 42 which provide access to certain other components within shunt 20 the details of which will be discussed in greater detail below thus as master control unit 24 is inserted in the abdomen is it also oriented within the patient subcutaneously such that access ports 40 and 42 are readily accessible further the placement of master control 24 is preferably.