Abstract:
An adjustable height tool for locating a magnetically readable and settable valve implanted in a living being. The locator can include a wall having a first perimeter. A platform can be disposed within the first perimeter. A valve cut-out can disposed within the platform and can approximate at least a portion of the shape of the valve. A movable foot can be disposed below the platform by which a displacement element moves the foot at least one of toward or away from the platform. This movement increases or decreases the distance between the platform and the skin/valve. Two or more recesses can be disposed in the foot and the recesses can be aligned with the valve cut-out. The displacement element can maintain the alignment of the recesses and the cut-out while moving the foot.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates generally to surgically implantable fluid drainage systems. More specifically, the invention relates to extracorporeal tools for locating adjustable valves used for cerebrospinal fluid drainage. 
       BACKGROUND 
       [0002]    Hydrocephalus is a neurological condition caused by the abnormal accumulation of cerebrospinal fluid (CSF) within the ventricles, or cavities, of the brain. Hydrocephalus, which can affect infants, children and adults, arises when the normal drainage of CSF in the brain is blocked in some way. Such blockage can be caused by a number of factors, including, for example, genetic predisposition, intraventricular or intracranial hemorrhage, infections such as meningitis, or head trauma. Blockage of the flow of CSF consequently creates an imbalance between the rate at which CSF is produced by the ventricular system and the rate at which CSF is absorbed into the bloodstream. This imbalance increases pressure on the brain and causes the ventricles to enlarge. Left untreated, hydrocephalus can result in serious medical conditions, including subdural hematoma, compression of the brain tissue, and impaired blood flow. 
         [0003]    Hydrocephalus is most often treated by surgically inserting a shunt system to divert the flow of CSF from the ventricle to another area of the body, such as the right atrium, the peritoneum, or other locations in the body where CSF can be absorbed as part of the circulatory system. Various shunt systems have been developed for the treatment of hydrocephalus. Typically, shunt systems include a ventricular catheter, a shunt valve and a drainage catheter. At one end of the shunt system, the ventricular catheter can have a first end that is inserted through a hole in the skull of a patient, such that the first end resides within the ventricle of a patient, and a second end of the ventricular catheter that is typically coupled to the inlet portion of the shunt valve. The first end of the ventricular catheter can contain multiple holes or pores to allow CSF to enter the shunt system. At the other end of the shunt system, the drainage catheter has a first end that is attached to the outlet portion of the shunt valve and a second end that is configured to allow CSF to exit the shunt system for reabsorption into the bloodstream. Typically, the shunt valve is palpatable by the physician through the patient&#39;s skin after implantation. The shunt valves, which can have a variety of configurations, can be designed to allow adjustment of their fluid drainage characteristics after implantation. 
         [0004]    It is also important to be able to externally read or verify the setting of the valve. With some adjustable valves, x-ray images are used to determine the current setting of the valve, before and after adjustment. With other adjustable valves, the orientation of a rotor in the valve can be read magnetically, using a magnetic compass-like device positioned above the valve, outside the skin of the patient. In examples, both the adjuster and the indicator are used in conjunction with a locator. The locator tool is used in the process of determining the location of the valve under the skin and subsequently to maintain this established position. The adjuster and the indicator tools engage within the locator tool to perform their function. 
         [0005]    Although tools and methods exist for adjusting CSF shunt valve settings, as do other tools and methods for reading a valve setting, some have difficulty performing their function if the underlying valve protrudes too far from the skull into the locator. These are instances where the patient may have a thick or thin scalp, or a smaller or larger skull than is typical. In these instances, the valve interferes with the placement and operation of the adjustor and/or indicator. Parallel placement of the locator to the implanted valve while in closest proximity to the implanted valve whilst permitting complete engagement between the locator and the indicator and adjustment tools enables successful operation of these tools. 
         [0006]    Thus, a need exists for a locator that can adjust for the height of the valve to enable the locator to be held by the user against the skin in a position generally parallel to the implanted valve so as to prevent interference between the skin/valve and the adjuster/locator or the skin/valve and the indicator/locator. 
       SUMMARY 
       [0007]    Accordingly, the present invention provides an adjustable height tool for determining the location of and subsequently to maintaining this established position of a magnetically readable and settable valve implanted in a living being. The locator can include a wall having a first perimeter. This perimeter can be a function of a diameter and/or circumference of the wall. A platform can be disposed within the first perimeter, typically near the center or bottom of the wall. A valve cut-out can be disposed within the platform. The cut-out approximates at least a portion of the shape of the valve, and can receive that portion or the skin thereabove. A movable foot can be disposed below the platform by which a displacement element moves the foot, at least one of, toward or away from the platform. This movement increases or decreases the distance between the platform and the skin/valve. Two or more recesses can be disposed in the foot and the recesses can be aligned with the valve cut-out. This alignment can allow any portion of the valve not captured inside the space of the wall or foot to have clearance under the foot. Additionally, the displacement element maintains the alignment of the recesses and the cut-out while moving the foot to minimize clearance or interference between the platform and the skin/valve. 
         [0008]    The above tool can also include a plurality of indicators disposed on the wall. These can indicate one or more valve settings. The plurality of indicators can have a fixed orientation in relation to the cut-out. Then, the displacement element can maintain the orientation of the plurality of indicators and the cut-out while moving the foot. This can allow for consistent readings and adjustments of the valve. 
         [0009]    Turning to the displacement element, it can, in one example, only permit movement of the foot in fixed increments. Alternately, it can be infinitely adjustable within a range of heights between the platform and the skin/valve or bottom of the foot. In addition, the displacement element can provide feedback as to the movement of the foot. 
         [0010]    Another example of a locator can include the wall having the first perimeter, the platform disposed within the first perimeter and the valve cut-out disposed within the platform. In this example, the cut-out receives a portion of the valve and the displacement element moves the foot to control the amount of the valve received in the valve cut-out. As above, the movable foot can be disposed below the platform. In other examples, at least a portion of the foot can be disposed above the platform and displace below the platform as the foot is extended. 
         [0011]    As above, the locator can also have two or more recesses disposed in the foot and aligned with the valve cut-out. Further, the displacement element can maintain the alignment of the recesses and the cut-out while moving the foot. Furthermore, the plurality of indicators can be disposed on the wall indicating one or more valve settings. These plurality of indicators have a fixed orientation in relation to the cut-out and the displacement element can maintain the orientation of the plurality of indicators and the cut-out while moving the foot. 
         [0012]    Another example is a method for locating the magnetically readable and settable valve implanted in a living being using the adjustable height tool. The steps can include locating the valve, positioning the locator over the valve, adjusting the height of the foot of the locator so that the foot of the locator supports the hand placement of the locator while the platform is in closest proximity to the valve. Note that too much offset between the locator and the indicator/adjustor generally results in the magnetic coupling between the particular tool and valve that is less than optimal, making it more difficult to read or adjust the valve with certainty. The closer the tool is to the implant the better the ability to read or adjust the valve. When the tool is too close to the implant, it means either, or, both of the below examples. In one example, the skin/valve protrudes thru the cutout and the locator sits in contact with the skin above the valve and then tilts to contact some portion of the foot. This is an unstable position and anything less than parallel orientation between the valve and tools is less than ideal. Another example is that the skin protruding thru cutout prevents the indicator and the adjustor from sitting flush within the locator, and again this would be less than parallel, and thus less than ideal. However, once properly placed, the valve can be adjusted. Other steps can be orienting the cut-out of the locator with the valve and adjusting the height of the foot of the locator while maintaining the orientation of the cut-out and valve. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    This invention is described with particularity in the appended claims. The above and further aspects of this invention may be better understood by referring to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
           [0014]    The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements. 
           [0015]      FIG. 1A  is an illustration of a typical valve implanted in a patient; 
           [0016]      FIG. 1B  is a top view of an example of a locator; 
           [0017]      FIG. 1C  is an illustration of the valve and locator as used on a patient; 
           [0018]      FIG. 2A  is a top-side profile view of an example of a locator; 
           [0019]      FIG. 2B  is a cross-sectional view along line II-II of  FIG. 1C  illustrating the valve and locator in use with the foot retracted; 
           [0020]      FIG. 2C  is an exploded view of the locator; 
           [0021]      FIG. 3  is a cross-sectional view along line II-II of  FIG. 1C  illustrating the valve and locator in use with the foot extended; 
           [0022]      FIG. 4  is a bottom-side profile view of an example of a locator; 
           [0023]      FIG. 5  is a bottom-side profile view of another example of a locator; 
           [0024]      FIG. 6  is flow chart illustrating an example of a method of adjusting the locator; 
           [0025]      FIG. 7  is flow chart illustrating another example of a method of adjusting the locator; 
           [0026]      FIG. 8  is an exploded view of a further example of a locator; 
           [0027]      FIG. 9  is a bottom-side profile view of a further example of a locator; 
           [0028]      FIGS. 10 and 10A  are side views of the further example of the locator in the retracted and extended positions, respectively; 
           [0029]      FIGS. 11 and 11A  are front side views of the further example of the locator in the retracted and extended positions, respectively; and 
           [0030]      FIG. 12  is a cross-sectional view along line  12 - 12  of  FIG. 10A . 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings. 
         [0032]    Methods and integrated tools of the present invention enable a physician to consistently and reliably locate an implantable, magnetically settable valve (valve) and change a setting of (adjust) the valve from a current setting to a target setting without interference from the valve. In an example, the valve is used to control, via its setting, at least one of CSF drainage flow and pressure for a patient with hydrocephalus, is implanted under a patient&#39;s scalp or another portion of the patient&#39;s skin, and is adjustable from outside (above) the patient&#39;s skin but needs to be located. 
         [0033]    Other tools and methods for extracorporeally reading and adjusting a hydrocephalus valve are disclosed in U.S. Pat. No. 8,038,641 entitled “Tools and Methods for Programming an Implantable Valve”, which is hereby incorporated by reference in its entirety. Within the scope of the present invention, features of the various examples disclosed herein can be used in any combination to construct additional integrated tools and methods for reading and adjusting an implantable valve. 
         [0034]      FIGS. 1A ,  2 B, and  3  illustrate a generalized implantable valve  100  implanted beneath a patient&#39;s skin  102 . The valve  100  includes a magnetic axis  104  which is the point of reference used to adjust the valve  100  or determine its settings. In an example, the valve  100  has a plurality of predetermined settings corresponding to a plurality of predetermined flows and pressures. In an example, the plurality of settings comprises eight settings. 
         [0035]    It is to be understood that the valve  100  can be any magnetically settable, implantable valve. In an embodiment, the valve  100  is unlocked by placing a magnetic field over the magnetic axis  104 . In a further embodiment, the attractive magnetic field for setting the valve can be provided by a single magnetic source that can be either a permanent magnet or an electromagnet. 
         [0036]      FIG. 1A  illustrates the valve  100  implanted under the skin  102  of a patient&#39;s skull S. Once implanted, the valve is under the skin and typically covered by hair. Additionally, the area surrounding the valve may experience localized swelling, especially after surgery. Also, as mentioned above, the patient may have a thin/thick scalp or small/large skull. Thus, a fixed foot can accommodate a range of sizes, while an adjustable foot accommodates a larger range, of bigger or smaller sizes. To locate the valve  100  under the skin  102 , the user typically palpates the skin  102  until she can feel the valve  100 . To facilitate the adjustment of the valve, a locator  200  is placed over the valve  100  on top of the skin  102  of the skull S. 
         [0037]      FIG. 1B  illustrates an example of the locator  200 . The locator  200  can be typically circular and can have a diameter D. The locator  200  can have a cut-out  202  or gap shaped similar to the valve  100 . The presence of the cut-out  202  allows the user to palpate, to feel and reposition the locator  200 . Further, where skin is not thick or swollen, the cut-out  202  in the shape of the valve  100  can aid in positioning and orienting by mating the bulge under the skin with the cut-out  202 . This allows the locator  200  to be oriented in the proper direction when placed over the valve  100 . The cut-out  202  can be oriented such that once placed over the valve  100  the magnetic axis  104  is aligned with a center  204  of the locator  200 . While an example can be circular, the locator  200  can have any shape to allow an adjustor and/or indicator to perform their functions. Thus, in one example, the locator  200  can be non-circular and composed of numerous line segments. 
         [0038]    The locator  200  can also have indicators  206 , these can be visual markings without or with petals or tabs extending outside a first perimeter  208  defined by the diameter D (wherein first perimeter  208  can equal π×diameter D).  FIG. 1C  illustrates a top view of the locator  200  placed over the valve  100  on the patient&#39;s skull S. 
         [0039]    Turning now to  FIGS. 2A and 2B , a top-side and cross section of the locator  200  are illustrated, respectively. The cut-out  202  of the locator  200  can be placed over the valve  100  and can even receive a small portion of the valve  100 , as the skin  102  may allow. The cut-out  202  can be formed in a platform  210  of the locator  200 . The locator  200  also can have a circumferential wall  212  depending from, and past, the platform  210  and, in one example, encircling the entire platform  210 . The indicators  206  can depend from the circumferential wall  212  and a height  214  of the circumferential wall  212  can form a space or volume, within the locator  200 . This space can be both above and below the platform  210 . 
         [0040]    In the normal operation of the locator  200 , as noted above, it is placed over the valve  100 . The valve  100  and skin  102  can stay below the platform  210  and may not protrude through the cut-out  202 . When an adjustor (not illustrated) is placed within the locator  200 , it functions best if it is in contact with the platform  210  while positioned as close to the implanted valve as allowable and while parallel to the valve. In that way, the valve can be adjusted. However, if the skin  102  does protrude too much through the cut-out  202  such that the indicator or adjustor do not sit flush or the locator sits against the skin in a position less than parallel to the valve, the present example of the locator  200  can include an adjustable foot  220  below the platform  210  to increase the distance between the valve  102  and the cut-out  202 /platform  210 . See,  FIGS. 2A ,  2 C,  3 , and  4 . 
         [0041]    The foot  220  engages the patient&#39;s skin  102  and can be displaced both toward and away from the platform  210  to remove or create additional space below the locator  200 . The foot  220  has a second perimeter  222  approximately equal to the first perimeter  208  of the wall  212 . The foot  220  can be disposed within or outside of the first perimeter  208  of the wall  212 , thus dictating its size in relation to the first perimeter  208 . 
         [0042]    The foot  220  can have recesses  224  formed in at least two places along the perimeter  222 . The recesses  224  are aligned with the cut-out  202  and allow a portion of the valve  100  to pass under the foot  220  when the locator  200  is placed over the valve  100 . 
         [0043]    The foot  220  is moved in relation to the platform  210  with a displacement element  226 . The displacement element  226  can be one or more of the many examples noted below, but all have a common feature. The displacement element  226  can keep the recesses  224  aligned with the cut-out  202  when the foot  220  is being displaced. Examples of the displacement element  226  can be sloped groove and pin relationship, spaced threads, detents, loading by an elastic element, rotating cuff, etc. 
         [0044]    The adjustment element  226  can displace the foot  220  over a range of additional heights  228 . The additional height  228  can be dynamic, in which the foot  220  can be at any height within the range of additional heights  228 . Alternately, the additional heights  228  can be stepwise, in which the heights  228  change in a fixed sequence of set increments. These heights  228  can also control the amount, if any, of the valve  100  and/or skin  102  that protrudes through the cut-out  202 . 
         [0045]    For example, the full additional height  228  can be 7.5 mm. Using a spring as the adjustment element  226 , the platform  210  can be at full height above the skin  102  and the locator  200  depressed during use. This allows the cut-out  202  to be moved into contact with the valve  100  without regard of the exact distance the valve  100  protrudes from the skin  102 . Alternately, the additional height  228  can be incremented in equal 1.5 mm “steps.” Differently, each step can have a distinct height. For example, the five steps can be 0.5 mm, 0.75 mm, 1.0 mm, 1.5 mm, 1.75 mm, and 2.0 mm. The locator  200  can also include a marker  230  to assist the user as to which direction to actuate either the foot  220  or the adjustment element  226  to increase the height  228 . Alternately, the marker  230  can indicate the direction to decrease the height  228 . 
         [0046]    In an example, the height can be adjusted by pulling or turning the foot  220  in relation to the wall  212  to increase or decrease the distance. Each step can be accompanied by an audio or tactile indication to inform a user as to that the platform  210  has changed height through the “step.” The indications can be a “click” as the foot  220  changes increments, or some form of vibration. Further, the foot  220  can be locked into place by common means, either temporarily or permanently, once the proper height is determined. 
         [0047]    Another example of the foot  220  and adjustment element  226  is that one or both of them keep the recesses  224  aligned with the indicators  206 . This can be important, as the indicators  206  should always stay is the same relation to the cut-out  202  for consistency in the readings and adjustment of the valve  100 . For example, as illustrated in  FIG. 1B , the number “6” is at the 12 o&#39;clock position when the cut-out has the illustrated “vertical” orientation, and that indicator should remain consistently located as the foot  220  is displaced. 
         [0048]      FIG. 3  illustrates the cross-section of the locator  200  while engaged with the patient&#39;s skin  102  over the valve  100 . As compared with  FIG. 2B , the foot  220  provides additional clearance between the platform  210  and the skin  102 , so the skin can be swollen into that space. 
         [0049]      FIG. 4  illustrates the bottom of the locator  200  and the alignment of the recesses  224  and the cut-out  202 .  FIG. 5  illustrates another example, illustrated from the bottom. While the above examples describe a foot  220 , the foot  220  can also include two or more feet. The foot  220  illustrated in  FIG. 5 , for example, can be two unconnected arcs. In a multiple foot  220  example, the recesses  224  can be gaps  232  between the feet  220  or still formed in the feet. 
         [0050]      FIG. 6  illustrates a flow chart of an example of a method using the above device. A user can palpate the skin  102  to locate the valve  100  (step  400 ). The user can position the locator  200  over the valve  100  once located (step  402 ). The user can then adjust the height of the foot  220  of the locator  200  (step  404 ) so the valve  100  and/or skin  102  does not protrude through the cut-out  202 . In use, avoiding contact between skin/valve and cut-out  202  means that the foot  220  supports the locator  200  on the skin  102  and the locator  200  can then be parallel to the implanted valve  100 . 
         [0051]    Further, with the locator  200  in place, the user can determine the existing setting of the valve  100 , with, for example, an indicator tool (not illustrated) (step  406 ). The user then inserts the adjustor  300  in the locator  200  to adjust the valve  100  (step  408 ), in one example, by rotating the adjustor  300 . The adjustor  300  is then removed from the locator  200  (step  410 ) and the new setting can be confirmed with the indicator tool (step  412 ). 
         [0052]      FIG. 7  illustrates another method of the present invention. As above, the valve  100  is located (step  500 ). The locator  200  is placed over the valve  100  (step  502 ). The locator  200  is oriented as to align the cut-out  202  with the valve  100  (step  504 ). The foot  220  is then adjusted to increase the height of the platform  210  above the skin  102  of the patient (step  506 ) to achieve minimal contact and parallel positioning. While the foot  220  is adjusted, the orientation of the locator  200  is relation to the valve  100  is maintained (step  508 ). The method can also include the steps to determine and adjust the settings of the valve  100  as described above. 
         [0053]      FIGS. 8-12  illustrate a further example of the locator  600 . The locator  600  can be divided into three parts, a crown  601 , a frame  603 , and an adjustment ring  605 .  FIG. 8  illustrates all three parts separated. The crown  601  can have a cut-out  602  or a gap shaped similar to the valve  100 . The cut-out  602  can be oriented such that once placed over the valve  100  the magnetic axis  104  is aligned with a center  604  of the locator  600 . The cut-out  606  can be formed in a platform  610  on the crown  601 . The crown  601  also can have a circumferential wall  616  depending from, and past, the platform  610  and, in one example, encircling the entire platform  610 . Indicators  606 , which can be visual markings denoting the setting of the valve  100 , can depend from the circumferential wall  616 . The circumferential wall  616  can also form a space or volume, within the crown  601 . This space can be both above and below the platform  610 . In one example, the crown  601  can also include minor recesses  623  aligned with the cut-out  602  and the recesses  624  in the foot  620 . 
         [0054]    Turning to the example of the frame  603 , it can generally include an adjustable foot  620  below the platform  610  to increase the distance between the valve  106  and the cut-out  602 /platform  610 . The foot  660  can be displaced both toward and away from the platform  610  to remove or create additional space below the locator  600 . The foot  620  can include the recesses  624  formed in at least two places along the frame  603 . The recesses  624  can be aligned with the cut-out  602  and allow a portion of the valve  100  to pass under the foot  620  when the locator  600  is placed over the valve  100 . 
         [0055]    The frame  603  can also include a male thread  625  that mates with a female thread  627  on the adjustment ring  205 . Note that the threads can be reversed in different examples. The adjustment ring  605  can act as part of the displacement element  626 . The combination of the male thread  625  and the female thread  627  can move the foot  620 /frame  603  in or out relative to the crown  601 . An interference element  629  between the adjustment ring  605  and the crown  601  maintains the orientation of the two pieces to each other. The interference element  629  can be pins which can move in a circumferential groove  631  formed in the crown  601 . The crown  601  can also include can also include an indicator  630 , illustrated as an arrow, to inform the user of the proper direction to twist the adjustment ring  205  to displace the foot  620 . The interference element  629  can, in some examples, allow for the smooth displacement of the foot  620  when the adjustment ring  605  is turned. In other examples, the interference element  629  can permit only a step-wise height change by the foot  620 . The changes in height can either be uniform, or varied, as noted above. 
         [0056]    While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.