reference is now made to fig3 , which illustrates schematically an example of a tube element 50 suitable for use at the distal end of the shunt . in the example shown in fig3 , the fluid draining openings are arranged in arrays of slots down the length of the tube , each array being positioned at a different angular position around the circumference of the tube . in the example shown in fig3 , two visible rows of slots 52 , 54 are shown arranged at angularly orthogonal positions relative to each other , but such a tube may typically have four such rows , arranged at 90 ° to each other , or any other number of rows of openings . furthermore , although the tube is shown having an essentially cylindrical profile , this being the most convenient shape to manufacturer , tubes with other sectional profile shapes can also be used in this application . reference is now made to fig4 a and 4b , which illustrate schematically a cleaning element adapted for use with the drain tube of fig3 . fig4 a is a side view of the cleaning element , while fig4 b is an end view thereof . the cleaner element has a central shaft 41 with a number of bristles 42 , 44 attached thereto . the bristles are preferably located longitudinally along the shaft such that the distance between successive bristles is the same as the distance between successive openings in the tube . likewise they should preferably be located radially around the shaft at the same angular intervals as the openings in the tube . in the example shown in fig4 a and 4b , four radial sets of bristles are shown located at right angles to each other . the arrangement of bristles should be such that when the cleaner is positioned correctly , the bristles are located opposite the openings in the tube . reference is now made to fig5 and 6 , each illustrating the completely assembled self - cleaning shunt head . fig5 is a cutaway drawing of the head , while fig6 is an “ x - ray ” isometric drawing of the head . in fig5 , the bristles 44 are shown protruding into the slots 54 . in the isometric drawing of fig6 , both orthogonal sets of bristles are shown protruding into their respective slots . bristles 44 extend in the vertical direction of the drawing upwards and downwards into the slots 54 , while bristles 42 extended in the horizontal direction of the drawing sideways into the slots 52 . in order for the bristles to perform their cleaning action , the cleaning element must be vibrated . one particularly simple way of achieving such vibration is by having one or more onboard magnets or ferromagnetic slugs attached to the cleaner shaft , or by making the cleaner shaft itself of a magnetic or magnetized material , and applying an external alternating magnetic field by means of a coil or a vibrating permanent magnet , that will influence the small magnet ( s ) or ferromagnetic element on the cleaner element and cause vibrations thereof . this implementation enables unlimited operation time , since the activation energy for generating the vibration is provided externally and is not dependent on the use of onboard batteries , while also maintaining simplicity of operation . the applied field direction may be such that the cleaning element vibrates along its length , or in any other direction other than axial which causes the bristles to penetrate the slot openings , or in any combination of such motions . thus , for example , since the shaft diameter may be small compared with the internal diameter of the tube , sufficient clearance can be provided for the cleaner element to vibrate in a rotation motion around axes perpendicular to the axis of the tube , such that the cleaner performs a see - saw type of motion , with bristles at opposite ends penetrating slots at opposite sides of the tube . in general , the vibratory motion generation system should be such as to reduce as much as possible sensitivity to direction of the externally applied field , so as not to restrict the positioning of the patient when the cleaning procedure is activated . entry of bristles into the slots in any manner which results in successful clearance of the slots may be advantageous . as an alternative to causing the shaft to vibrate , it is possible to generate the vibrations directly in the fibers , such as by making them of a magnetized or a magnetic material and applying an external alternating magnetic field , or by any other suitable method . the external field can be applied from outside of the subject &# 39 ; s body in which the shunt is installed . an alternative method of generating the vibrations could be by use of an ultrasound signal applied externally at a frequency related to the mechanical self - resonant frequency of the bristles , such that they vibrate when the field is applied . the vibrations must be of such magnitude and direction that the bristles vibrate within the openings in the tube . optimally , the bristles should penetrate the slots to their full depth , so that no tissue growth or blockage can occur at any depth in the slots . limiting the extension outside the tube may be advisable in order to avoid injury to tissues around the tube , though some penetration outside the tube may be allowable . there may be several slots in different directions so that the cleaning process can be made less sensitive to the direction of the applied external field . it is also possible to have an on - board vibration generator 56 mounted on the cleaning element , such as is shown schematically in fig5 . operation of the cleaning process can then be simpler , as there is no need to activate any external influence , but rather the cleaning is done autonomously . the on - board power supply may be long - lasting , or may be capable of being charged by an external power supply . the on - board vibration generator can be a mechanical transducer , such as by means of an eccentric or stepped rotating element , a magnetic transducer or a piezoelectric transducer , or any other form of vibration generator . the internal battery can be recharged when necessary by means of an externally applied induced field , as is known in the art . as an alternative to the use of an on - board battery , the vibration transducer can be provided with leads to an external power connector , and the vibration transducer powered directly by connection of an external power source to the connector when the cleaning procedure is to be activated . in use , the tube with the openings is installed on the end of the shunt catheter before installation , with the cleaner inside . the combination cleaner element and tube are attached to a regular shunt tube instead of its punctured segment . the final result looks similar to the original shunt in shape and size , except that the punctured segment has been replaced by the tube and bristled cleaner . as an alternative , the cleaner may be embedded within the original shunt head tube . as an alternative , the cleaner element can be installed once the shunt is in position . at predetermined intervals the cleaner is vibrated in order to ensure that the openings remain clear of ingrowing tissue . the movement of the cleaning element inside the tube depends on the alignment of the magnet and the amplitude and frequency of the magnetic field generated by the external source ( using the example of a magnetic field driven application ). the motion generated may be such that the bristles can generally move in two ways : ( i ) forward and backward inside the tube slots , by axial motion . ( ii ) inside and outside the tube slots by radial or rotational motion or a combination of both . by its movement , the cleaner changes the hydrodynamic flow pattern inside the slots , making it impossible for tissue to grow near and inside the openings , and preventing living tissue from growing inside the slots . in addition , the bristles themselves can mechanically clean out any tissue which begins to form in the openings between cleaning sessions . reference is now made to fig7 , which illustrates a further implementation of the present device , utilizing a second cylindrical tube 70 whose operation adds a safety factor when installing the device . the second tube 70 fits concentrically inside the first tube 50 , and has a series of openings 74 in essentially the same positions as the openings in the outer tube . in order to prevent the bristles from sticking into surrounding tissue during installation of the shunt , the two concentric tubes are arranged to be aligned such that the openings are not opposite each other during insertion , such that the bristles are prevented from protruding from the outer tube and causing possible damage to surrounding tissue . once the head of the shunt is installed into its desired position , the inner tube can be moved such that the openings of the inner and outer tube are now aligned , and the bristles can pass into the openings to perform their cleaning action . this movement can be generated by means of a simple mechanical motion imparted by the installation device once final location has been confirmed . the mutual motion of the inner and outer tubes is most conveniently performed in a lateral direction , though a rotational movement may also be used . in the drawing of fig7 , the openings are shown in their open aligned positions , during normal use after installation , so that the bristles can operate correctly in keeping the openings clear . it is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove . rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art . the foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description . it is not intended to be exhaustive or to limit the invention to the precise form disclosed . many modifications and variations are possible in light of this disclosure . it is intended that the scope of the invention be limited not by this detailed description , but rather by the claims appended hereto .
a self cleaning inlet head for use on a shunt . the head has a tube with openings disposed in predetermined positions in its wall , and a cleaning element installed inside the tube . the cleaning element may comprise a central shaft with a number of bristles protruding therefrom , preferably in locations substantially identical to the positions of the openings in the wall of the tube . mutual vibratory motion between the cleaning element and the tube causes at least some of the bristles to enter the openings , thereby keeping them clear , and preventing tissue growth into them . the vibratory motion may be generated by the action of an external field on a responsive part of the cleaning element , such as an external magnetic field operating on a magnetic or magnetized part of the cleaning element or the bristles . alternatively , the external field may be an ultrasound field operating on the bristles .