Patent Description:
Hydrocephalus is a condition in which an excessive accumulation of cerebral spinal fluid is encountered. Cerebral spinal fluid is the clear fluid that surrounds the brain and the spinal cord. The excessive accumulation results in abnormal dilation of the ventricles within the brain. This dilation may cause the accumulation of potentially harmful pressure on the tissues of the brain.

Hydrocephalus is most often treated through the utilization of a shunt system. Cerebral spinal fluid shunt systems divert the flow of cerebral spinal fluid from a site within the ventricles to another area of the body where the cerebral spinal fluid can be absorbed as part of the circulatory system.

Shunt systems are commonly installed by creating a small hole within the skull, commonly referred to as a burr hole. A ventricular catheter is passed through the burr hole and positioned in the ventricular space. A peritoneal catheter is positioned at another location within the body where the cerebral spinal fluid can be diverted and absorbed. For example, it is common to either shunt the cerebral spinal fluid from the cerebral ventricles to the peritoneal cavity for reabsorption into the blood through the peritoneum or the cerebral spinal fluid may be shunted from the cerebral ventricles into the right atrium of the heart where the cerebral spinal fluid is directly shunted into the blood circulation.

In accordance with a typical procedure, incisions are made for the ventricular catheter and the peritoneal catheter. The peritoneal catheter is then positioned, and a burr hole is formed within the skull. Thereafter, the ventricular catheter is positioned. The ventricular catheter and the peritoneal catheter are then connected to a shunt valve which controls the flow of cerebral spinal fluid from the ventricle, through the ventricular catheter, and to the peritoneal catheter. The incisions are then closed.

In addition to common complications, such as shunt malfunction, shunt failure and shunt infection, the utilization of catheters passing through the burr hole with the shunt valve positioned between the skull and the scalp results in other problems. For example, the shunt valve may resorb bone thereby creating a defect in the skull. In addition, the shunt valve and/or ventricular catheter are susceptible to movement. Still further, the ventricular catheter is susceptible to kinks as it passes through and around the burr hole.

<CIT> discloses a differential pressure sensing device which is fully implanted in the body of a patient to monitor internal pressure such as intracranial pressure. A movable element in the sensor communicates with the internal pressure of the body to be measured on one side and the atmospheric pressure on the other, the latter communicated through the intact skin and a nearly coplanar membrane. <FIG> of <CIT> shows a shunt plug housing including a shunt valve recess formed therein and a recess with an access hole, a shunt valve shaped and dimensioned for positioning within the shunt valve recess of the shunt plug housing.

<CIT> discloses a ventricular catheter assembly including a proximal catheter and a cooperating cranial cover. The cranial cover includes a base plate having an opening aligned with a burr hole in the skull of a person. A guide extends upwardly from the base plate and receives the proximal catheter.

Finally, <CIT> discloses a cerebral and/or interface system having a housing mechanism configured to be at least partially spaced in a cavity formed in the subject's skull; an attaching mechanism for attaching the housing mechanism to the subject's skull; a sealing mechanism for providing a fluid-tight seal between the housing mechanism and the subject's skull; a control mechanism spaced within the housing mechanism; a communication mechanism with one or more sensors embedded in the subject's brain connecting the control mechanism to the subject's brain; and a power source spaced within the housing mechanism.

With the foregoing in mind, it is desirable to improve upon current techniques for the placement of cerebral spinal fluid shunt systems.

The present invention provides a cerebral spinal fluid shunt plug including a shunt plug housing including an upper surface, a lower surface, continuous side walls extending between the upper surface and the lower surface, as well as about the periphery of the shunt plug housing, a shunt valve recess being formed in the upper surface of the shunt plug housing and either an intracranial monitoring recess with an access hole or a window recess with a central access hole formed in the upper surface of the shunt plug housing, the shunt plug housing further including passageways allowing the shunt valve recess to communicate with an exterior of the shunt plug housing, the access holes or passageways being shaped and dimensioned to allow for connection of a ventricular catheter and a peritoneal catheter with the shunt valve housed within the recess of the shunt plug housing, the housing being shaped and dimensioned for positioning within a physician formed cranial hole in a manner allowing the upper surface of the housing to be substantially flush with an outer surface of a skull and a projection along the lower surface being positioned within the cranial hole; and a window or an intracranial monitoring device shaped and dimensioned for respectively positioning within either the window recess or the intracranial monitoring recess of the shunt plug housing.

In some embodiments, the recess with an access hole is a window recess with an access hole and the cerebral spinal fluid shunt plug includes the window shaped and dimensioned for positioning within the window recess.

In some embodiments, the cerebral spinal fluid shunt plug further includes an intracranial monitoring device recess with an access hole and an intracranial monitoring device shaped and dimensioned for the passage through the access hole of the intracranial monitoring device recess.

In some embodiments, the central access hole extending from the window recess to a lower surface of the shunt plug housing is shaped and dimensioned for the passage of light, sound, and/or radio waves therethrough so as to access the brain for imaging and treatment.

In some embodiments, the window is optically transparent.

In some embodiments, the window is optically translucent to all light waves.

In some embodiments, the window is sonolucent.

In some embodiments, the window is radiolucent.

In some embodiments, the window is optically transparent, optically translucent to all light waves, is sonolucent, and is radiolucent.

In some embodiments, the window comprises polymethyl methacrylate (PMMA).

In some embodiments, the window is a lucent disk.

In some embodiments, the lucent disk includes an upper surface and a lower surface and the curvature of the upper surface differs from the curvature of the lower surface.

In some embodiments, the lucent disk includes an alignment feature.

In some embodiments, the alignment feature includes a series of markings at different depths within the lucent disk.

In some embodiments, the series of markings includes an outer first lucent disk marking and an inner second lucent disk marking formed along the upper and lower surfaces, respectively, of the lucent disk.

In some embodiments, the series of markings further includes an interior lucent disk marking formed within a body of the lucent disk and in alignment with the outer first lucent disk marking and an inner second lucent disk marking.

In some embodiments, the lucent disk includes channels.

In some embodiments, the intracranial monitoring device is a wireless intracranial monitoring device.

In some embodiments, the intracranial monitoring device includes a probe that passes through the access hole. Other advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention.

The detailed embodiments of the present invention are disclosed herein. It should be understood, however, that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as a basis for teaching one skilled in the art how to make and/or use the invention.

Referring to <FIG> (not part of the present invention), various embodiments of a cerebral spinal fluid shunt plug <NUM> are disclosed in accordance with the present invention. It should be appreciated similar reference numerals are used for the various different embodiments. The shunt plug <NUM> is shaped and dimensioned for positioning within a physician formed cranial hole <NUM>. The shunt plug <NUM> is further shaped and dimensioned for housing a shunt valve <NUM> in a reliable and secure manner so that a ventricular catheter <NUM> and peritoneal catheter <NUM> may be positioned without fear that the shunt valve <NUM> might move and/or the catheters <NUM>, <NUM> might become disengaged from their desired locations.

The shunt plug <NUM> includes a shunt plug housing <NUM> composed of a bottom first housing member <NUM> and a top second housing member <NUM>. The bottom first housing member <NUM> and top second housing member <NUM> are shaped and dimensioned for mating so as to define the shunt plug housing <NUM> in which the shunt valve <NUM> is positioned. In accordance with the disclosed embodiments, the shunt valve <NUM> will be placed within the shunt plug housing <NUM>, so as to create the shunt plug <NUM> of the present invention, at the time of surgery. Further, in accordance with a disclosed embodiment the shunt plug housing is made of HDPE, although it is appreciated other materials may be used without departing from the spirit of the present invention.

The shunt plug housing <NUM>, when the first housing member <NUM> and the second housing member <NUM> are connected together as shown with reference to <FIG> and <FIG>, includes a first end <NUM>, a second end <NUM>, a first lateral side <NUM>, and a second lateral side <NUM>. The shunt plug housing <NUM> also includes an upper surface <NUM>, a lower surface <NUM>, and a continuous side wall <NUM> extending between the upper surface <NUM> and the lower surface <NUM>, as well as about the periphery of the shunt plug housing <NUM>.

In accordance with the disclosed embodiments, and considering the procedure discussed below in greater detail, the shunt plug housing <NUM> is structured with consecutive and overlapping cylinders (for example, three cylinders as shown with reference to <FIG>, and <FIG> and six cylinders as disclosed with reference to <FIG>, <FIG>). While a shape in accordance with the disclosed embodiment is disclosed herein for the purpose of explaining the present invention, it is appreciated various shapes may be employed within the spirit of the present invention. As will be appreciated after reading the installation procedure presented below, the consecutive and overlapping cylinder structure was selected as a means of optimizing the installation procedure based upon the utilization of a single trephine to create consecutive and overlapping burr holes that ultimately define the cranial hole <NUM> in which the shunt plug <NUM> is positioned. As such, the shape of the shunt plug and the mechanism for the creation of the cranial hole are intimately related and may be varied based upon various needs and requirements.

Considering the embodiment disclosed with reference to <FIG>, and <FIG> (not part of the present invention), the side wall <NUM> of the disclosed embodiment is formed with a scalloped shape wherein a plurality of arcuate segments extends about the periphery of the shunt plug housing <NUM>. The arcuate segments 36a, 36b at the first end <NUM> and the second end <NUM> of the shunt plug housing <NUM> define an arcuate surface of approximately <NUM> degrees to <NUM> degrees, and the arcuate segments 36c, 36d located at the center of the side wall <NUM> along the first and second lateral sides <NUM>, <NUM> define an arc of approximately <NUM> to <NUM> degrees. In accordance with a preferred embodiment, the outer surface of the side wall <NUM> may be bowed outwardly so as to define a convex outer surface.

The embodiment disclosed with reference to <FIG>, <FIG> (not part of the present invention) is similarly shaped, but includes additional arcuate surfaces requiring the formation of additional burr holes during the installation process. In particular, the shunt plug <NUM> disclosed in <FIG>, <FIG> would require the formation of six burr holes in a highly specific pattern. The pattern employed creates a larger area for accommodating the needs of shunt valves having larger dimensions.

A recess <NUM> is formed within the shunt plug housing <NUM>. The recess <NUM> is defined by recessed surfaces 38a, 38b formed along the surfaces of the first housing member <NUM> and the second housing member <NUM>. The recess <NUM> is in communication with the exterior of the shunt plug housing <NUM> via access holes <NUM>, <NUM> extending from the exterior surface of the shunt plug housing <NUM> to the recess <NUM>. As will be explained below in greater detail, these access holes <NUM>, <NUM> allow for connection of the ventricular catheter <NUM> and the peritoneal catheter <NUM> with the shunt valve <NUM> housed within the recess <NUM> of the shunt plug housing <NUM>. As with the recess <NUM>, the access holes <NUM>, <NUM> are defined by recessed surfaces 42a, 42b, 44a, 44b formed along the surfaces of the first housing member <NUM> and the second housing member <NUM>. Depending upon the shape of the shunt plug housing <NUM> and the shunt valve <NUM> to be positioned therein, the position of the access holes <NUM>, <NUM> may be varied to optimize the ultimate positioning of the peritoneal catheter <NUM> and the ventricular catheter <NUM> (see, for example, <FIG> and <FIG>).

In particular, and with reference to <FIG>, the first housing member <NUM> includes an exterior surface <NUM> that defines the exterior surface of the shunt plug housing <NUM> when the first and second housing members <NUM>, <NUM> are connected together (as shown in <FIG>) to form the complete shunt plug housing <NUM>. The first housing member <NUM> also includes a mating surface <NUM> that engages the mating surface <NUM> of the second housing member <NUM> when the first and second housing members <NUM>, <NUM> are connected together to form the complete shunt plug housing <NUM>.

With this in mind, the first housing member <NUM> includes a first end <NUM>, a second end <NUM>, and first and second lateral sides <NUM>, <NUM>. The first housing member <NUM> also includes a top surface <NUM> defining the lower surface <NUM> of the shunt plug housing <NUM>, a lower surface <NUM> that forms part of the mating surface <NUM> of the first housing member <NUM> that mates with the mating surface <NUM> of the second housing member <NUM> so as to define the junction of the first housing member <NUM> and the second housing member <NUM>, as well as the recess <NUM> in which the shunt valve <NUM> is positioned. The first housing member <NUM> also includes side walls 64a-d extending between the top surface <NUM> and the lower surface <NUM>. The side walls 64b, 64c, 64d at the first and second lateral sides <NUM>, <NUM>, as well as the second end <NUM>, of the first housing member <NUM> define a portion of the exterior surface of the shunt plug housing <NUM>. The side wall 64a at the first end <NUM> of the first housing member <NUM> forms part of the mating surface <NUM> of the first housing member <NUM> that mates with the mating surface <NUM> of the second housing member <NUM> so as to define the junction of the first housing member <NUM> and the second housing member <NUM>.

The second housing member <NUM> includes a first end <NUM>, a second end <NUM>, and first and second lateral sides <NUM>, <NUM>. The second housing member <NUM> includes a top surface <NUM> defining the upper surface <NUM> of the shunt plug housing <NUM>, a lower surface <NUM> that forms part of the mating surface <NUM> of the second housing member <NUM> that mates with the mating surface <NUM> of the first housing member <NUM> so as to define the junction of the first housing member <NUM> and the second housing member <NUM>, as well as the recess <NUM> in which the shunt valve <NUM> is positioned. The second housing member <NUM> also includes an upwardly directed wall portion <NUM> extending upwardly from the lower surface <NUM> at the first end <NUM> of the second housing member <NUM>. The wall portion <NUM> includes an interior surface <NUM> forming part of the mating surface <NUM> of the second housing member <NUM> that mates with the mating surface <NUM> of the first housing member <NUM> so as to define the junction of the first housing member <NUM> and the second housing member <NUM>. In particular, the interior surface <NUM> of the wall portion <NUM> is shaped and dimensioned to mate with the side wall 64a at the first end <NUM> of the first housing member <NUM>. The surface of the wall portion <NUM> opposite the interior surface <NUM> forms part of the side wall of the shunt plug housing <NUM> at the first end <NUM> of the shunt plug housing <NUM>.

The second housing member <NUM> also includes side walls 86a-d extending between the lower surface <NUM> and the top surface <NUM>. The side walls 86a-d at the first and second lateral sides <NUM>, <NUM>, as well as the first and second ends <NUM>, <NUM>, of the second housing member <NUM> define a portion of the exterior surface of the shunt plug housing <NUM>.

Mating of the first housing member <NUM> with the second housing member <NUM> is further facilitated by the provision of protrusions <NUM> along the lower surface <NUM> of the second housing member <NUM> and matingly shaped indentations <NUM> along the lower surface <NUM> of the first housing member <NUM>.

As discussed above, the recess <NUM> in which the shunt valve <NUM> is positioned, as well as the access holes <NUM>, <NUM> for the passage of the ventricular and peritoneal catheters <NUM>, <NUM>, is formed within the shunt plug housing <NUM>. The recess <NUM> and access holes <NUM>, <NUM> are defined by recessed surfaces 38a, 38b, 42a, 42b, 44a, 44b formed along the surfaces of the first housing member <NUM> and the second housing member <NUM>. In particular, the recessed surfaces 38a, 38b, 42a, 42b defining the recess <NUM> and the first access hole <NUM> are formed along the lower surface <NUM> of the second housing member <NUM> and the lower surface <NUM> of the first housing member <NUM>. The recessed surfaces 44a, 44b defining the second access hole <NUM> are formed along the side wall 64a of the first housing member <NUM> at the first end <NUM> thereof and along the interior surface <NUM> of the wall portion <NUM> at the first end <NUM> of the second housing member <NUM>.

With the foregoing description of the first housing member and the second housing member in mind, it is appreciated that the first and second housing members may take various shapes depending upon the desired inter-engagement of these two members when the shunt plug housing is fully formed and ready for use.

As briefly discussed above, the recess <NUM> defined within the shunt plug housing <NUM> is shaped and dimensioned for placement of the shunt valve <NUM> therein. As those skilled in the art will appreciate, a variety of shunt valves are known in the art and the present shunt plug housing <NUM> may be adapted to accommodate a variety of these shunt valves. For example, the following shunt valves may be used in conjunction with the present invention: CODMAN®/Integra HAKIM® and Certas Programmable Shunt Valve, MEDTRONIC® STRATA®, SOPHYSA® POLARIS®, Ascuelap proGAV®, and INTEGRA® OSV II®. The present invention may also be used in conjunction with the Rickam reservoir and other similar reservoirs used in cerebral spinal fluid management. In accordance with a preferred embodiment, the shunt plug housing <NUM> should have a surface area along its upper surface <NUM> of at least five cm<NUM> so as to accommodate various shunt valves and to provide the necessary space for placement of the shunt valve <NUM> within the recess <NUM> defined within the shunt plug housing <NUM>.

Once the shunt valve <NUM> is positioned between the first housing member <NUM> and the second housing member <NUM> within the recess <NUM> defined thereby, the first housing member <NUM> may be connected to the second housing member <NUM> so as to fully enclose the shunt valve <NUM> therein. Thereafter, the shunt plug <NUM> of the present invention may be utilized for the purpose of performing a cerebral spinal fluid shunt procedure.

In accordance with yet another embodiment (not part of the present invention) as shown with reference to <FIG> (which shows this embodiment in various shapes to accommodate shunt valves from various manufacturers), the shunt plug is structured such that the shunt valve is uncovered. In particular, and as with the previous embodiment, the shunt plug <NUM> is shaped and dimensioned for housing a shunt valve <NUM> in a reliable and secure manner so that a ventricular catheter <NUM> and peritoneal catheter <NUM> may be positioned without fear that the shunt valve <NUM> might move and/or the catheters <NUM>, <NUM> might become disengaged from their desired locations.

The shunt plug <NUM> includes a shunt plug housing <NUM> composed of a bottom first housing member <NUM>. In accordance with the disclosed embodiments, the shunt valve <NUM> will be placed within the shunt plug housing <NUM>, so as to create the shunt plug <NUM> of the present invention, at the time of surgery.

The shunt plug housing <NUM> includes a first end <NUM>, a second end <NUM>, a first lateral side <NUM>, and a second lateral side <NUM>. The shunt plug housing <NUM> also includes an upper surface <NUM>, a lower surface <NUM>, and continuous side walls 236a-d extending between the upper surface <NUM> and the lower surface <NUM>, as well as about the periphery of the shunt plug housing <NUM>. As will be appreciated based upon the following disclosure, the lower surface <NUM> is provided with a projection 234p that ultimately fits within the cranial hole <NUM> to assist in holding the shunt plug <NUM> in position after installation. With this in mind, the projection 234p is elliptically shaped to fit within the cranial hole <NUM> as shown in <FIG>.

While particular shapes of the shunt plug housing <NUM> in accordance with the disclosed embodiment are disclosed herein for the purpose of explaining the present invention, it is appreciated various shapes may be employed within the spirit of the present invention. As such, the shape of the shunt plug and the mechanism for the creation of the cranial hole are intimately related and may be varied based upon various needs and requirements. For example, and in contrast with the embodiments described above with reference to <FIG>, the shunt plug housing includes a substantially elliptical shape.

A recess <NUM> is formed within the upper surface <NUM> of the shunt plug housing <NUM>. The recess <NUM> is in communication with the exterior of the shunt plug housing <NUM> via access passageways <NUM>, <NUM> extending from the exterior surface of the shunt plug housing <NUM> to the recess <NUM>. As will be explained below in greater detail, these access holes (or passageways) <NUM>, <NUM> allow for connection of the ventricular catheter <NUM> and the peritoneal catheter <NUM> with the shunt valve <NUM> housed within the recess <NUM> of the shunt plug housing <NUM>. The access passageways <NUM>, <NUM> are defined by recessed surfaces formed along the upper surface <NUM> of the shunt plug housing <NUM>. Depending up the shape of the shunt plug housing <NUM> and the shunt valve <NUM> to be positioned therein, the position of the access holes (or passageways) <NUM>, <NUM> may be varied to optimize the ultimate positioning of the peritoneal catheter <NUM> and the ventricular catheter <NUM>.

As discussed above, the recess <NUM> in which the shunt valve <NUM> is positioned, as well as the access holes <NUM>, <NUM> for the passage of the ventricular and peritoneal catheters <NUM>, <NUM>, is formed within the shunt plug housing <NUM>. The recess <NUM> and access holes <NUM>, <NUM> are defined by recessed surfaces 238a, 242a, 244a formed along the upper surface <NUM> of the shunt plug housing <NUM>. In particular, the recessed surface 238a defining the recess <NUM> is formed along the upper surface <NUM> of the shunt plug housing <NUM>; the recessed surface 242a defining the first access hole (or passageway) <NUM> is formed along the upper surface <NUM> adjacent the first end <NUM>; and the recessed surfaces 244a defining the second access hole (or passageway) <NUM> are formed along the side wall 264a of the shunt plug housing <NUM> at the second end <NUM> thereof.

As briefly discussed above, the recess <NUM> defined within the shunt plug housing <NUM> is shaped and dimensioned for placement of the shunt valve <NUM> therein. As those skilled in the art will appreciate, and as explained above in conjunction with the prior embodiment, a variety of shunt valves are known in the art and the present shunt plug housing <NUM> may be adapted to accommodate a variety of these shunt valves. The present invention may also be used in conjunction with the Rickam reservoir and other similar reservoirs used in cerebral spinal fluid management. In accordance with a preferred embodiment, the shunt plug housing <NUM> should have a surface area along its upper surface <NUM> of at least five cm<NUM> so as to accommodate various shunt valves and to provide the necessary space for placement of the shunt valve <NUM> within the recess <NUM> defined within the shunt plug housing <NUM>.

Once the shunt valve <NUM> is positioned within the recess <NUM> of the shunt plug housing <NUM> the shunt plug <NUM> of the present invention may be utilized for the purpose of performing a cerebral spinal fluid shunt procedure.

Referring to <FIG> (not part of the present invention), and with particular reference to the embodiment disclosed in <FIG>, and <FIG>, the procedure is first initiated by making the required incision for passage of the peritoneal catheter <NUM>. Thereafter, a cranial incision is made and the cranial hole <NUM> is created utilizing a template <NUM> (shown in broken lines) and predefined trephine (not shown). In contrast to prior art procedures, a singular burr hole is not formed. Rather, adjacent circular holes 104a-c (for example, three as shown in the disclosed embodiment) are formed creating the cranial hole <NUM> that is shaped for snuggly fitting the shunt plug <NUM> therein. As with the shape of the shunt plug <NUM>, the cranial hole <NUM> created in accordance with the present invention includes scalloped edges. In particular, the cranial hole <NUM> includes first and second ends <NUM>, <NUM> with an arcuate surface <NUM>, <NUM> of approximately <NUM> to <NUM> degrees, as well as first and second lateral arcuate surfaces <NUM>, <NUM> of approximately <NUM> to <NUM> degrees. Given the matching shape of the cranial hole <NUM> and the shunt plug <NUM>, the shunt plug <NUM> will fit snugly within the cranial hole <NUM> thereby minimizing potential movement after completion of the procedure.

With the cranial hole <NUM> completed, the ventricular catheter <NUM> is positioned within the ventricle and the peritoneal catheter <NUM> is positioned with the body as using well know medical procedures. Thereafter, the ends of the peritoneal catheter <NUM> and the ventricular catheter <NUM> adjacent the shunt plug <NUM> may be secured to the shunt valve <NUM> housed within the shunt plug <NUM> by passing the ends of the respective catheters into the first and second access holes <NUM>, <NUM> formed at locations along the exterior of the shunt plug housing <NUM>. Thereafter, the shunt plug <NUM> is positioned within the cranial hole <NUM>. The shunt plug <NUM> is mounted within the cranial hole <NUM> such that the upper surface <NUM> is substantially flush with the outer surface of the skull <NUM>. It is, however, appreciated the exact positioning of the shunt plug will vary based upon specific anatomical characteristics of the patient. Once the shunt plug <NUM> is properly positioned, the shunt valve <NUM> is actuated utilizing well known procedures, and the procedure is completed in accordance with known medical procedures.

As discussed above, the shunt plug of the present invention may take various shapes. One possible shape where simplicity is considered to be important might involve an elliptically shaped shunt plug housing <NUM> as shown with reference to <FIG>. Such an embodiment would require a cranial hole <NUM> formed by the creation of two burr holes <NUM> with two connecting cuts <NUM> made in the shape of the shunt plug <NUM> so as to allow for placement of the shunt plug <NUM> within the cranial hole <NUM>. It is, however, appreciated the cranial hole may be made using any method of creating an elliptical craniectomy acceptable by those skilled in the art. When using such an embodiment, it is appreciated variations in the cuts <NUM> between the two burr holes <NUM> are likely and the shunt plug <NUM> is therefore provided with a plurality of attachment tabs <NUM> that may be used to secure the shunt plug <NUM> to the area of the skull <NUM> immediately adjacent to the cranial hole <NUM>.

Referring to <FIG> (not part of the present invention), and with particular reference to the embodiment disclosed in <FIG> (not part of the present invention), the procedure is first initiated by making the required incision for passage of the peritoneal catheter <NUM>. Thereafter, a cranial incision is made and the cranial hole <NUM> in the skull <NUM> is created utilizing a template <NUM> (shown in broken lines). In accordance with a preferred embodiment, and considering the elliptical shape of the cranial hole <NUM>, burr holes are formed at the respective ends of the template <NUM>, and the remainder of the skull <NUM> is cut away along the lines as defined by the template <NUM>. As with the prior embodiment, it is appreciated the cranial hole may be made using any method of creating an elliptical craniectomy acceptable by those skilled in the art. Given the matching shape of the cranial hole <NUM> and the shunt plug <NUM>, the shunt plug <NUM> will fit snugly within the cranial hole <NUM> thereby minimizing potential movement after completion of the procedure.

With the cranial hole <NUM> completed, the ventricular catheter <NUM> is positioned within the ventricle and the peritoneal catheter <NUM> is positioned with the body as using well know medical procedures. Thereafter, the shunt plug housing <NUM> is positioned within the cranial hole <NUM> with the upper surface <NUM> facing upwardly, and the ventricular catheter <NUM> is cut to an appropriate length. The ends of the peritoneal catheter <NUM> and the ventricular catheter <NUM> adjacent the shunt plug <NUM> are then secured to the shunt valve <NUM> and the shunt valve <NUM> is positioned within the shunt plug housing <NUM>. In particular, the shunt plug <NUM> is mounted within the cranial hole <NUM> such that the upper surface <NUM> is substantially flush with the outer surface of the skull <NUM> and the projection 234p along the lower surface <NUM> is positioned within the cranial hole <NUM>. As such, portions along the periphery of the shunt plug housing <NUM> overlie the skull <NUM>, and screws may be passed therethrough to facilitate secure attachment of the shunt plug <NUM> to the skull. It is, however, appreciated the exact positioning of the shunt plug will vary based upon specific anatomical characteristics of the patient. Once the shunt plug <NUM> is properly positioned and secured in place using known techniques, the shunt valve <NUM> is actuated utilizing well known procedures, and the procedure is completed in accordance with known medical procedures.

With the foregoing in mind, the present shunt plug offers multiple advantages. It eliminates mobility of the shunt valve and/or reservoir. As a result, the shunt valve location is known and will not migrate caudal, cephalad, anterior, or posterior which can cause challenges during revision surgery. The ventricular catheter is a precise distance from the shunt valve to the ventricle, therefore mobility of the shunt valve can displace the location of the ventricular catheter. The present shunt plug eliminates cranial deformity as it avoids the need to implant the shunt valve on top of the cranium and underneath the scalp. As a result, pressure on the scalp is minimized along with any accompanying complications such as pain or implant extrusion. In addition, the present shunt plug minimizes micro-motion; that is, the well documented fact that implant micro-motion can lead to bone resorption (causing further deformity) and can lead to infection. Finally, the present shunt plug minimizes catheter kinking as the sharpest angle in the catheters pathway is the top of the perforator made burr hole and by controlling the angle of entry of the catheter, the risk of occlusion is minimized.

It is appreciated that once the cerebral spinal fluid shunt plug of the present invention is implanted within the cranium and covered by the scalp, it may be desirable to identify, for example, via triangulation, a specific point or points on the cerebral spinal fluid shunt plug, in particular, the shunt valve itself; for example, to identify and/or locate the center of the programmable portion of the programmable shunt valve or reservoir. To achieve this, and with reference to <FIG> (not part of the present invention), various embodiments are disclosed. It is appreciated these variations are disclosed in accordance with the embodiment described with reference to <FIG> and <FIG> (not part of the present invention), and the variations described herein may be applied to any of the embodiments disclosed herein.

In accordance with the embodiment disclosed with reference to <FIG> (not part of the present invention), physical bumps 280a-d are provided on the housing <NUM> of the shunt plug <NUM>. While four bumps are shown in accordance with a disclosed embodiment, it is appreciated the number and location of the bumps may be varied to suit specific needs. In accordance with the embodiment disclosed with reference to <FIG> (not part of the present invention), magnets or ferromagnetic properties <NUM> are integrated into the housing <NUM>. The magnets or ferromagnetic properties <NUM> are oriented in the housing <NUM> to allow an external magnet to be employed in triangulating a particular location upon the shunt plug <NUM>. In accordance with the embodiment disclosed with reference to <FIG> (not part of the present invention), an RFID (radio-frequency identification) device <NUM> is embedded in the housing <NUM> of the shunt plug <NUM> with the ability to identify a point on the shunt plug <NUM>. In accordance with the embodiment disclosed with reference to <FIG>, radiographic and/or acoustic properties <NUM> are integrated into the housing <NUM> that allow specific points of the shunt plug <NUM> to be seen by imaging modalities (CT, MRI, X-ray, Ultrasound, etc.. While the various identification devices described above are integrated into the housing, it is appreciated they might also be integrated into the shunt valve without departing from the spirit of the present invention.

Referring to <FIG>, an embodiment of the present cerebral spinal fluid shunt plug <NUM> according to the invention is disclosed. As with the prior embodiments, the shunt plug <NUM> is shaped and dimensioned for positioning within a physician formed cranial hole <NUM> and is further shaped and dimensioned for housing a shunt valve <NUM> in a reliable and secure manner so that a ventricular catheter <NUM> and peritoneal catheter <NUM> may be positioned without fear that the shunt valve <NUM> might move and/or the catheters <NUM>, <NUM> might become disengaged from their desired locations. Still further, this embodiment is shaped and dimensioned for integration of a wireless intracranial monitoring device <NUM> with the shunt plug <NUM>.

The shunt plug <NUM> includes a shunt plug housing <NUM> composed of a bottom first housing member <NUM>. In accordance with the disclosed embodiments, the shunt valve <NUM> and the wireless intracranial monitoring device <NUM> are placed within the shunt plug housing <NUM>, so as to create the shunt plug <NUM> of the present invention, at the time of surgery.

The shunt plug housing <NUM> is substantially triangular shaped (with curved and extended corners, as well as arcuate walls) and includes a first end <NUM>, a second end <NUM>, a short first lateral side <NUM>, and a long second lateral side <NUM>. However, and as with the prior embodiments, it is appreciated various shapes may be employed within the spirit of the present invention and the shape of the shunt plug housing may be varied without departing from the spirit of the present invention.

The shunt plug housing <NUM> also includes an upper surface <NUM>, a lower surface <NUM>, and continuous side walls 436a-d extending between the upper surface <NUM> and the lower surface <NUM>, as well as about the periphery of the shunt plug housing <NUM>. As will be appreciated based upon the following disclosure, and as with the embodiment of <FIG>, the lower surface <NUM> is provided with a projection 434p that ultimately fits within the cranial hole <NUM> to assist in holding the shunt plug <NUM> in position after installation. With this in mind, the projection 434p is shaped to fit within the cranial hole <NUM> as shown in <FIG>.

While a particular shape of the shunt plug housing <NUM> in accordance with the disclosed embodiment is disclosed herein for the purpose of explaining the present invention, it is appreciated various shapes may be employed within the spirit of the present invention. As such, the shape of the shunt plug and the mechanism for the creation of the cranial hole are intimately related and may be varied based upon various needs and requirements. For example, and in contrast with the embodiments described above with reference to <FIG>, the shunt plug housing includes a substantially triangular shape.

A shunt valve recess <NUM> is formed within the upper surface <NUM> of the shunt plug housing <NUM>. The shunt valve recess <NUM> is in communication with the exterior of the shunt plug housing <NUM> via access passageways <NUM>, <NUM> extending from the exterior surface of the shunt plug housing <NUM> to the shunt valve recess <NUM>. As will be explained below in greater detail, these access holes (or passageways) <NUM>, <NUM> allow for connection of the ventricular catheter <NUM> and the peritoneal catheter <NUM> with the shunt valve <NUM> housed within the shunt valve recess <NUM> of the shunt plug housing <NUM>. The access passageways <NUM>, <NUM> are defined by recessed surfaces formed along the upper surface <NUM> of the shunt plug housing <NUM>. Depending upon the shape of the shunt plug housing <NUM> and the shunt valve <NUM> to be positioned therein, the position of the access holes (or passageways) <NUM>, <NUM> may be varied to optimize the ultimate positioning of the peritoneal catheter <NUM> and the ventricular catheter <NUM>.

As discussed above, the shunt valve recess <NUM> in which the shunt valve <NUM> is positioned, as well as the access holes <NUM>, <NUM> for the passage of the ventricular and peritoneal catheters <NUM>, <NUM>, are formed within the shunt plug housing <NUM>. The shunt valve recess <NUM> and access holes <NUM>, <NUM> are defined by recessed surfaces 438a, 442a, 444a formed along the upper surface <NUM> of the shunt plug housing <NUM>. In particular, the recessed surface 438a defining the shunt valve recess <NUM> is formed along the upper surface <NUM> of the shunt plug housing <NUM>; the recessed surface 442a defining the first access hole (or passageway) <NUM> is formed along the upper surface <NUM> adjacent the first end <NUM>; and the recessed surfaces 444a defining the second access hole (or passageway) <NUM> are formed along the side wall 464a of the shunt plug housing <NUM> at the second end <NUM> thereof.

As briefly discussed above, the shunt valve recess <NUM> defined within the shunt plug housing <NUM> is shaped and dimensioned for placement of the shunt valve <NUM> therein. As those skilled in the art will appreciate, and as explained above in conjunction with the prior embodiment, a variety of shunt valves are known in the art and the present shunt plug housing <NUM> may be adapted to accommodate a variety of these shunt valves. The present invention may also be used in conjunction with the Rickam reservoir and other similar reservoirs used in cerebral spinal fluid management. In accordance with a preferred embodiment, the shunt plug housing <NUM> should have a surface area along its upper surface <NUM> of at least five cm<NUM> so as to accommodate various shunt valves and to provide the necessary space for placement of the shunt valve <NUM> within the shunt valve recess <NUM> defined within the shunt plug housing <NUM>.

As will be explained below in detail, once the shunt valve <NUM> is positioned within the shunt valve recess <NUM> of the shunt plug housing <NUM> the shunt plug <NUM> of the present invention may be utilized for the purpose of performing a cerebral spinal fluid shunt procedure.

In addition to the shunt valve recess <NUM> for the shunt valve <NUM> as discussed above, the shunt plug housing <NUM> of this embodiment further includes an intracranial monitoring device recess <NUM> formed within the upper surface <NUM> of the shunt plug housing <NUM> adjacent to the short first lateral side <NUM>. The intracranial monitoring device recess <NUM> is shaped and dimensioned for positioning of an intracranial monitoring device <NUM>, in particular, the head <NUM> of the intracranial monitoring device <NUM>, therein. As such, and as will be appreciated based upon the following disclosure, the intracranial monitoring device recess <NUM> is provided with a central access hole <NUM> extending from the intracranial monitoring device recess <NUM> to the lower surface <NUM> of the shunt plug housing <NUM>. The central access hole <NUM> is shaped and dimensioned for the passage of the probe <NUM> of the wireless intracranial monitoring device <NUM> therethrough and to a desired position within the brain.

The intracranial monitoring device recess <NUM> in which the wireless intracranial monitoring device <NUM> is positioned, as well as the central access hole <NUM> for the passage of the probe <NUM>, is formed within the shunt plug housing <NUM>. The intracranial monitoring device recess <NUM> is defined by recessed surfaces <NUM> formed along the upper surface <NUM> of the shunt plug housing <NUM>. In particular, the recessed surface <NUM> defining the intracranial monitoring device recess <NUM> is formed along the upper surface <NUM> of the shunt plug housing <NUM>.

As briefly discussed above, the intracranial monitoring device recess <NUM> defined within the shunt plug housing <NUM> is shaped and dimensioned for placement of the wireless intracranial monitoring device <NUM> therein. As those skilled in the art will appreciate, and as explained above in conjunction with the prior embodiment, a variety of wireless intracranial monitoring devices are known in the art and the present shunt plug housing <NUM> may be adapted to accommodate a variety of these wireless intracranial monitoring device <NUM>. However, and in accordance with a preferred embodiment of the present invention, the wireless intracranial monitoring device <NUM> is one or a combination of the wireless intracranial pressure monitoring devices disclosed in <CIT> and <CIT> and <CIT>, <CIT>,<CIT>, <CIT>, <CIT>, and <CIT>. In accordance with this embodiment, the shunt plug housing <NUM> should have a surface area along its upper surface <NUM> sufficient to accommodate various shunt valves and wireless intracranial monitoring devices.

The inclusion of the wireless intracranial monitoring device <NUM> with the shunt plug <NUM> of the present invention results in a reduction in the pressure generated by mounting implantable devices on the scalp and allows for measurement of the cerebral spinal fluid manage by the shunt valve <NUM> itself.

Further functionality may be achieved by using a wireless intracranial monitoring device offering multiple sensing capabilities (multimodal), for example, as disclosed in <CIT>.

Once the shunt valve <NUM> and the wireless intracranial monitoring device <NUM> are positioned within the shunt valve recess <NUM> of the shunt plug housing <NUM> the shunt plug <NUM> of the present invention may be utilized for the purpose of performing a cerebral spinal fluid shunt procedure as explained above.

With the inclusion of a wireless intracranial monitoring device <NUM> with the shunt plug <NUM> of the present invention, positioning of the shunt plug <NUM> becomes critical. As such, the installation procedure is modified as described below.

Referring to <FIG>, the procedure is first initiated by making the required incision for passage of the peritoneal catheter <NUM>. Thereafter, a cranial incision is made and the cranial hole <NUM> in the skull <NUM> is created utilizing a template <NUM> (shown in broken lines). In accordance with a preferred embodiment, and considering the triangular shape of the cranial hole <NUM>, burr holes are formed at the respective ends of the template <NUM>, and the remainder of the skull <NUM> is cut away along the lines as defined by the template <NUM>. As with the prior embodiment, it is appreciated the cranial hole may be made using any method acceptable to those skilled in the art. Given the matching shape of the cranial hole <NUM> and the shunt plug <NUM>, the shunt plug <NUM> will fit snugly within the cranial hole <NUM> thereby minimizing potential movement after completion of the procedure.

With the cranial hole <NUM> completed, the ventricular catheter <NUM> is positioned within the ventricle and the peritoneal catheter <NUM> is positioned with the body as using well know medical procedures. Thereafter, the shunt plug housing <NUM> is positioned within the cranial hole <NUM> with the upper surface <NUM> facing upwardly, and the ventricular catheter <NUM> is cut to an appropriate length. The ends of the peritoneal catheter <NUM> and the ventricular catheter <NUM> adjacent the shunt plug <NUM> are then secured to the shunt valve <NUM> and the shunt valve <NUM> is positioned within the shunt plug housing <NUM>. In particular, the shunt plug <NUM> is mounted within the cranial hole <NUM> such that the upper surface <NUM> is substantially flush with the outer surface of the skull <NUM> and the projection 434p along the lower surface <NUM> is positioned within the cranial hole <NUM>. As such, portions along the periphery of the shunt plug housing <NUM> overlie the skull <NUM>, and screws may be passed therethrough to facilitate secure attachment of the shunt plug <NUM> to the skull. It is, however, appreciated the exact positioning of the shunt plug will vary based upon specific anatomical characteristics of the patient. Once the shunt plug <NUM> is properly positioned and secured in place using known techniques, the wireless intracranial monitoring device <NUM> is positioned within the intracranial monitoring device recess <NUM> with the probe <NUM> extending into the brain.

As those skilled in the art will appreciate, proper positioning of the probe <NUM> of the intracranial monitoring device <NUM> and the ventricular catheter <NUM> of the shunt valve <NUM> are critical. The orientation of the wireless intracranial monitoring device <NUM>, for example, the probe <NUM> of the intracranial monitoring devices <NUM>, relative to ventricular catheter <NUM> of the shunt valve <NUM> is critical to understand and appreciate so as to avoid eloquent structures on the cortex of the brain; such as the trajectory between Kocher's point and the ventricles or previously necrosed brain damage in a traumatic injury or due to high intracranial pressure. Furthermore, by identifying the relative positions of the wireless intracranial monitoring device <NUM> and the shunt valve <NUM> to the cortex, the relationship of the shunt valve <NUM> and wireless intracranial monitoring device <NUM> relative to a target within the brain is surmised and eloquent structures of the brain are avoided. For example, and through the use of the present shunt plug <NUM> in conjunction with various computer based surgical guidance systems <NUM> as discussed below, it is possible for surgeons to fully appreciate the relationship of the intracranial monitoring device <NUM>, the shunt valve <NUM>, and/or the ventricular catheter <NUM> in relation to the shunt plug <NUM> and, therefore, the cortex. This enables the surgeon to place the intracranial monitoring device <NUM>, the shunt valve <NUM>, and/or the ventricular catheter <NUM> in a manner that minimizes the potential for cortical damage.

In practice, and prior to initiating the surgical procedure, virtual images of the shunt plug <NUM>, including both the shunt valve <NUM> and the intracranial monitoring device <NUM>, are generated. Virtual images of the patient, including the approximate location of the shunt plug <NUM> are also generated. Upon initiation of the surgical procedure movement of the actual shunt plug <NUM>, including the shunt valve <NUM>, shunt plug housing <NUM>, and the intracranial monitoring device <NUM>, relative to the patient is monitored in real-time. This is achieved by the integration of tracking devices 412t, 418t, 480t into or onto the respective shunt valve <NUM>, shunt plug housing <NUM>, and the intracranial monitoring device <NUM>. Additional tracking devices may be applied to the patient in a manner known to those skilled in the art. It should be appreciated that the tracking devices 412t, 418t, 480t may take a variety of forms so long as the computer-based guidance system <NUM> is capable of identifying the real-time movement of the various components of the shunt plug <NUM> being tracked. For example, the tracking devices may take the form of external tracking devices attached to the shunt plug, tracking devices integrated into the shunt plug, or existing structures of the shunt plug that are readily identifiable via the sensing structure of the computer-based guidance system <NUM>. Sensing may be achieved via various known techniques, including, but not limited to, infrared, electromagnetic, optical, etc. sensing techniques.

With this information and using a computer based surgical guidance system <NUM>, the shunt plug <NUM> is properly positioned within the patient. Once the shunt valve <NUM> and the wireless intracranial monitoring device <NUM> are properly positioned, they may be actuated utilizing well known procedures, and the procedure is completed in accordance with known medical procedures.

Referring to <FIG> and <FIG>, yet another embodiment of the present cerebral spinal fluid shunt plug <NUM> is disclosed. As with the prior embodiments, the shunt plug <NUM> is shaped and dimensioned for positioning within a physician formed cranial hole and is further shaped and dimensioned for housing a shunt valve <NUM> in a reliable and secure manner so that a ventricular catheter <NUM> and peritoneal catheter <NUM> may be positioned without fear that the shunt valve <NUM> might move and/or the catheters <NUM>, <NUM> might become disengaged from their desired locations. Still further, this embodiment is shaped and dimensioned for integration of a window in the form of a lucent disk <NUM> with the shunt plug <NUM>. Given the similarity between the embodiment disclosed with reference to <FIG> and the embodiment disclosed with reference to <FIG> and <FIG>, it is appreciated one shunt plug housing <NUM> may be used in conjunction with either the wireless intracranial monitoring device <NUM> of the embodiment disclosed with reference to <FIG> or the lucent disk <NUM> of the embodiment disclosed with reference to <FIG> and <FIG>. Further still, and with reference to <FIG>, an embodiment combining the lucent disk <NUM> and the wireless intracranial monitoring device <NUM> for use with a shunt valve <NUM> is disclosed.

The shunt plug <NUM> includes a shunt plug housing <NUM> composed of a bottom first housing member <NUM>. In accordance with the disclosed embodiments, the shunt valve <NUM> and the lucent disk <NUM> are placed within the shunt plug housing <NUM>, so as to create the shunt plug <NUM> of the present invention, at the time of surgery.

The shunt plug housing <NUM> also includes an upper surface <NUM>, a lower surface <NUM>, and continuous side walls 736a-d extending between the upper surface <NUM> and the lower surface <NUM>, as well as about the periphery of the shunt plug housing <NUM>. As will be appreciated based upon the following disclosure, and as with the embodiment of <FIG>, the lower surface (not shown) is provided with a projection (not shown) that ultimately fits within the cranial hole to assist in holding the shunt plug <NUM> in position after installation. With this in mind, the projection is shaped to fit within the cranial hole <NUM> as shown in <FIG>.

As discussed above, the shunt valve recess <NUM> in which the shunt valve <NUM> is positioned, as well as the access holes <NUM>, <NUM> for the passage of the ventricular and peritoneal catheters <NUM>, <NUM>, are formed within the shunt plug housing <NUM>. The shunt valve recess <NUM> and access holes <NUM>, <NUM> are defined by recessed surfaces 738a, 742a, 744a formed along the upper surface <NUM> of the shunt plug housing <NUM>. In particular, the recessed surface 738a defining the shunt valve recess <NUM> is formed along the upper surface <NUM> of the shunt plug housing <NUM>; the recessed surface 742a defining the first access hole (or passageway) <NUM> is formed along the upper surface <NUM> adjacent the first end <NUM>; and the recessed surfaces 744a defining the second access hole (or passageway) <NUM> are formed along the side wall 736a of the shunt plug housing <NUM> at the second end <NUM> thereof.

In addition to the shunt valve recess <NUM> for the shunt valve <NUM> as discussed above, the shunt plug housing <NUM> of this embodiment further includes a window recess <NUM> formed within the upper surface <NUM> of the shunt plug housing <NUM> adjacent to the short first lateral side <NUM>. The window recess <NUM> is shaped and dimensioned for positioning of a lucent disk <NUM>. As such, and as will be appreciated based upon the following disclosure, the window recess <NUM> is provided with a central access hole <NUM> extending from the window recess <NUM> to the lower surface <NUM> of the shunt plug housing <NUM>. The central access hole <NUM> is shaped and dimensioned for the passage of light, sound, and/or radio waves therethrough so as to access the brain for imaging and treatment.

The window recess <NUM> in which the lucent disk <NUM> is positioned, as well as the central access hole <NUM>, is formed within the shunt plug housing <NUM>. The window recess <NUM> is defined by recessed surfaces <NUM> formed along the upper surface <NUM> of the shunt plug housing <NUM>. In particular, the recessed surface <NUM> defining the window recess <NUM> is formed along the upper surface <NUM> of the shunt plug housing <NUM>.

While the embodiment described considers a situation wherein the shunt plug housing <NUM> may be used in conjunction with either the wireless intracranial monitoring device <NUM> of the embodiment disclosed with reference to <FIG> or the lucent disk <NUM> of the embodiment disclosed with reference to <FIG> and <FIG>, the shunt plug housing may be specifically designed for use with only the lucent disk. Considering such an embodiment, and with reference to <FIG>, the central access hole <NUM>" would be substantially enlarged such that the recessed surface <NUM>" positioned about the central access hole <NUM>" is made relatively small and is constructed to function as a ledge supporting the bottom surface of the lucent disk <NUM>" when it is positioned within the window recess <NUM>". By expanding the central access hole <NUM>", unattenuated passage of light, sound, radio, and other waves will be optimized.

As briefly discussed above, the window recess <NUM> defined within the shunt plug housing <NUM> is shaped and dimensioned for placement of the lucent disk <NUM> therein. In accordance with a preferred embodiment of the present invention, the lucent disk <NUM> is optically transparent, optically translucent to all light waves, sonolucent (that is, allowing passage of ultrasonic waves without production of echoes that are due to reflection of some of the waves), and/or radiolucent (that is, allowing passage of radio waves without production of echoes that are due to reflection of some of the waves). Further still, and in accordance with a disclosed embodiment, the lucent disk is made of polymethyl methacrylate (PMMA).

Through the provision of a lucent disk, a variety of options are available to medical practitioners wishing to provide the best treatment options to their patients. For example, lucent disk may be manufactured in a manner allowing for the transmission of ultrasonic waves as described in <CIT>, entitled "IMPLANTABLE SONIC WINDOW," ('<NUM> Patent). As explained in the '<NUM> Patent, a strong, porous sonically translucent material through which ultrasonic waves can pass for purposes of imaging the brain is employed, wherein the material is a polymeric material, such as polyethylene, polystyrene, acrylic, or poly(methyl methacrylate) (PMMA). In addition, <CIT>, entitled "METHOD OF MAKING WAVEGUIDE-LIKE STRUCTURES," ('<NUM> Publication) and <CIT>, entitled "CRANIAL IMPLANTS FOR LASER IMAGING AND THERAPY," ('<NUM> Publication) making waveguide-like structures within optically transparent materials using femtosecond laser pulses wherein the optically transparent materials are expressly used in the manufacture of cranial implants. The '<NUM> publication explains the use of optically transparent cranial implants and procedures using the implants for the delivery of laser light into shallow and/or deep brain tissue. The administration of the laser light can be used on demand, thus allowing real-time and highly precise visualization and treatment of various pathologies. Further still, Tobias et al. describe an ultrasound window to perform scanned, focused ultrasound hyperthermia treatments of brain tumors. Tobias et al. tested various materials to determine which material would best serve as an acoustical window in the skull and ultimately determined polyethylene transmitted a larger percentage of power than other plastics and would likely function well as an ultrasonic window. Further still, <NPL> provides further information regarding sonic windows.

Radiolucency as applied to the present invention allows a clinician to see the anatomy beneath the lucent disk <NUM> without "scatter" or interfering artifacts from the implant for diagnosis and follow-up. By another definition of radiolucency, radio waves are able to transmit easily through the lucent disk <NUM>, for example, via Bluetooth or other frequency transmission; which can serve many purposes including, but not limited to, data management and controller telemetry. The provision of radiolucency also allows for the integration of markings (as discussed below) made with radiographic materials, for example, barium sulfate, to be visible in contrast to the remainder of the craniofacial implant to allow for unique device identifiers or unique patient information to be visible on post-operative scans.

Considering the provision of optical lucency in the lucent disk <NUM>, the ability to optically transmit through the lucent disk <NUM> allows for: visualization of anatomy distal to the lucent disk <NUM>, the potential of higher bandwidth optical links (similar to radio transmission) between proximal adjunct devices, light to be emitted through the lucent disk <NUM> to adjacent anatomy which could aid in optogenetics, and imaging/therapeutic modalities that rely on light like optical coherence tomography from within the implant. Of note, this was shown to be true on a postoperative (day <NUM>) cranioplasty patient with the clear implant.

With the inclusion of a lucent disk <NUM> with the shunt plug <NUM> of the present invention, positioning of the shunt plug <NUM> becomes critical. As such, the installation procedure is as described below.

The procedure is first initiated by making the required incision for passage of the peritoneal catheter <NUM>. Thereafter, a cranial incision is made and the cranial hole in the skull is created utilizing a template. In accordance with a preferred embodiment, and considering the triangular shape of the cranial hole, burr holes are formed at the respective ends of the template, and the remainder of the skull is cut away along the lines as defined by the template. As with the prior embodiment, it is appreciated the cranial hole may be made using any method acceptable to those skilled in the art. Given the matching shape of the cranial hole and the shunt plug <NUM>, the shunt plug <NUM> will fit snugly within the cranial hole thereby minimizing potential movement after completion of the procedure.

With the cranial hole completed, the ventricular catheter <NUM> is positioned within the ventricle and the peritoneal catheter <NUM> is positioned within the body using well know medical procedures. Thereafter, the shunt plug housing <NUM> is positioned within the cranial hole with the upper surface <NUM> facing upwardly, and the ventricular catheter <NUM> is cut to an appropriate length. The ends of the peritoneal catheter <NUM> and the ventricular catheter <NUM> adjacent the shunt plug <NUM> are then secured to the shunt valve <NUM> and the shunt valve <NUM> is positioned within the shunt plug housing <NUM>. In particular, the shunt plug <NUM> is mounted within the cranial hole <NUM> such that the upper surface <NUM> is substantially flush with the outer surface of the skull <NUM> and the projection 734p along the lower surface <NUM> is positioned within the cranial hole. As such, portions along the periphery of the shunt plug housing <NUM> overlie the skull, and screws may be passed therethrough to facilitate secure attachment of the shunt plug <NUM> to the skull. It is, however, appreciated the exact positioning of the shunt plug will vary based upon specific anatomical characteristics of the patient. Once the shunt plug <NUM> is properly positioned and secured in place using known techniques, the lucent disk <NUM> is positioned within the window recess <NUM>.

In practice, and prior to initiating the surgical procedure, virtual images of the shunt plug <NUM>, including both the shunt valve <NUM> and the lucent disk <NUM>, are generated. Virtual images of the patient, including the approximate location of the shunt plug <NUM> are also generated. Upon initiation of the surgical procedure, movement of the actual shunt plug <NUM>, including the shunt valve <NUM>, shunt plug housing <NUM>, and the lucent disk <NUM>, relative to the patient is monitored in real-time. This is achieved by the integration of tracking devices (as discussed above with the prior embodiment shown with reference to <FIG>) into or onto the respective shunt valve <NUM>, shunt plug housing <NUM>, and the lucent disk <NUM>. Additional tracking devices may be applied to the patient in a manner known to those skilled in the art. It should be appreciated that the tracking devices may take a variety of forms so long as the computer-based guidance system is capable of identifying the real-time movement of the various components of the shunt plug <NUM> being tracked. For example, the tracking devices may take the form of external tracking devices attached to the shunt plug, tracking devices integrated into the shunt plug, or existing structures of the shunt plug that are readily identifiable via the sensing structure of the computer-based guidance system. Sensing may be achieved via various known techniques, including, but not limited to, infrared, electromagnetic, optical, etc. sensing techniques.

With this information and using a computer based surgical guidance system, the shunt plug <NUM> is properly positioned within the patient. Once the shunt valve <NUM> and the lucent disk <NUM> are properly positioned, they may be actuated utilizing well known procedures, and the procedure is completed in accordance with known medical procedures.

Considering the fact the lucent disk is optically transparent, optically translucent to all light waves, sonolucent, and/or radiolucent, various features have been integrated into the lucent disk in an effort to enhance the functionality thereof. While these features are described herein as individual embodiments, it is appreciated they may be combined in various combinations as the needs of a patient dictate.

In accordance with one embodiment as shown with reference to <FIG>, the lucent disk <NUM>' may be constructed with variations in shape designed to control the manner in which light, sound, radio, and other waves pass therethrough. Such variations in shape would be undertaken in a manner similar to the way in which eyeglasses are adjusted for each patient. For example, and with reference to the disclosed embodiment, the curvature of the upper surface <NUM> differs from the curvature of the lower surface 780ls wherein the upper surface <NUM> has a much larger radius of curvature.

In accordance with another embodiment as shown with reference to <FIG>, the lucent disk <NUM>" may be constructed with an alignment feature <NUM>. In accordance with a disclosed embodiment, the alignment feature <NUM> includes a series of markings 783a-c at different depths within the lucent disk. For example, an outer first lucent disk marking 783a and an inner second lucent disk marking 783b are formed along the upper and lower surfaces <NUM>, 780ls, respectively, of the lucent disk <NUM>. One or more additional interior lucent disk markings 780c may be formed within the body of the lucent disk <NUM> and in alignment with the outer first lucent disk marking 783a and an inner second lucent disk marking 783b. While an outer first lucent disk marking 783a, an inner second lucent disk marking 783b, and at least one additional interior lucent disk marking 783c are disclosed herein, it is appreciated various combinations of markings may be used within the spirit of the present invention.

The outer first lucent disk marking 783a, the inner second lucent disk marking 783b, and the plurality of additional interior lucent disk markings 783c are aligned such that when a transmitter of light, sound, radio, or other waves is properly aligned with the markings, the light, sound, radio, or other waves will be directed to the proper location within the cranium. Similarly, when one looks through the lucent disk <NUM> and the outer first lucent disk marking 783a, the inner second lucent disk marking 783b, and the at least one additional interior lucent disk markings 783c merge into a single location identifying image (for example, crosshairs or circles), a specific brain anatomy (or other structural element upon the surface of the brain) is identified by the single location identifying image. When the specific brain anatomy identified by the single location identifying image changes over time, the surgeon will know that something has shifted and will take appropriate action.

In accordance with one embodiment as shown with reference to <FIG>, the lucent disk may be constructed with wire channels <NUM> oriented for various purposes specific to different patients and treatment protocols.

The use of a lucent disk offers various advantages to address specific needs within the industry. For example, patients requiring ventriculoperitoneal shunting are postoperatively left with a high-profile shunt valve underneath their scalp and have high rates of complication and revision due to infection, occlusion, extrusion, and/or migration (dislodging/disconnecting) of the valve. Additionally, monitoring of intracranial pressure and ventricular size can be difficult and costly when complications arise, requiring lumbar punctures and CT scans to diagnose effectively. Patients receiving and using the present lucent disk would benefit from reduced profile of the shunt valve (level with the skull), reducing complications associated with pressure on the valve and restoring the native contour of the cranium. As well, due to high level of complication involved with ventriculoperitoneal shunting, ultrasound diagnostics would prove beneficial to rapidly, and noninvasively, monitor the size of the ventricles to correlate efficacy of the shunt and potential necessity of revision.

In accordance with yet another embodiment, the lucent element is integrated with the spinal fluid shunt plug <NUM> as a selectively attachable accessory in the form of a clear custom intercranial implant.

Referring to <FIG> and <FIG>, the spinal shunt plug is as described above with reference to <FIG> and similar reference numerals will be used. The shunt plug <NUM> includes a shunt plug housing <NUM> composed of a bottom first housing member <NUM>. The shunt plug housing <NUM> is substantially elliptically shaped (with curved and extended corners, as well as arcuate walls) and includes a first end <NUM>, a second end <NUM>, and first and second lateral sides <NUM>, <NUM>. However, and as with the prior embodiments, it is appreciated various shapes may be employed within the spirit of the present invention and the shape of the shunt plug housing may be varied without departing from the spirit of the present invention.

The shunt plug housing <NUM> also includes an upper surface <NUM>, a lower surface <NUM>, and continuous side walls 236a-d extending between the upper surface <NUM> and the lower surface <NUM>, as well as about the periphery of the shunt plug housing <NUM>. As will be appreciated based upon the following disclosure, and as with the embodiment of <FIG>, the lower surface <NUM> is provided with a projection (not shown) that ultimately fits within the cranial hole <NUM> to assist in holding the shunt plug <NUM> in position after installation. With this in mind, the projection is shaped to fit within the cranial hole <NUM> as shown in <FIG>.

As discussed above, the shunt valve recess <NUM> in which the shunt valve <NUM> is positioned, as well as the access holes <NUM>, <NUM> for the passage of the ventricular and peritoneal catheters <NUM>, <NUM>, are formed within the shunt plug housing <NUM>. The shunt valve recess <NUM> and access holes <NUM>, <NUM> are defined by recessed surfaces 238a, 242a, 244a formed along the upper surface <NUM> of the shunt plug housing <NUM>. In particular, the recessed surface 238a defining the shunt valve recess <NUM> is formed along the upper surface <NUM> of the shunt plug housing <NUM>; the recessed surface 242a defining the first access hole (or passageway) <NUM> is formed along the upper surface <NUM> adjacent the first end <NUM>; and the recessed surfaces 244a defining the second access hole (or passageway) <NUM> are formed along the side wall 264a of the shunt plug housing <NUM> at the second end <NUM> thereof.

As briefly discussed above, the shunt valve recess <NUM> defined within the shunt plug housing <NUM> is shaped and dimensioned for placement of the shunt valve <NUM> therein. As those skilled in the art will appreciate, and as explained above in conjunction with the prior embodiment, a variety of shunt valves are known in the art and the present shunt plug housing <NUM> may be adapted to accommodate a variety of these shunt valves.

The lucent element of this embodiment is a clear custom intercranial implant <NUM> shaped and dimensioned for positioning adjacent to the shunt plug <NUM>. The clear custom intercranial implant <NUM> includes an implant body <NUM> structured in a manner as used and known by those skilled in the art of cranial surgical procedures. The implant body <NUM> may take a variety of forms and is most commonly shaped and dimensioned for integration into the structure of a patient's skull; that is, the implant body has a geometry that substantially conforms to a resected portion of the patient's anatomy to which the implant is to be secured. Briefly, the implant body <NUM> includes an outer (commonly convex) first surface <NUM>, an inner (commonly concave) second surface <NUM>, and a peripheral edge <NUM> extending between the outer first surface <NUM> and the inner second surface <NUM>. The implant body <NUM> is shaped and dimensioned for engagement with the skull of the patient upon implantation in a manner well known to those skilled in the field of neurosurgical and neuroplastic reconstructive procedures. The outer first surface <NUM> and inner second surface <NUM> of the implant body <NUM> are preferably curved in a superior to inferior direction, a posterior to anterior direction, and a medial to lateral direction. In addition, the peripheral edge <NUM> has a substantial taper for resting upon a matching taper formed along the skull. It is, however, appreciated that this taper may vary (or not exist at all, that is, the peripheral edge may be substantially perpendicular relative to the outer first surface and the inner second surface) depending upon the specific needs.

In accordance with an embodiment, the implant body <NUM> is fabricated from a wide array of commonly-available biomaterials including, but not limited to, clear PMMA (Poly(methyl methacrylate)), PEEK (Polyether ether ketone), PEKK (Polyetherketoneketone), porous polyethylene, flexible silicone, cubic zirconium, titanium alloy, allograft, autograft, xenograft, glass, and/or various other tissue-engineered constructs. In fact, some of the biomaterials used in this novel device may be resorbable versus permanent with respect to time. In accordance with one embodiment, the implant body is ideally made of clear PMMA since it's fully translucent to light, sonolucent to ultrasound such that it allows for the passage of ultrasonic waves without the production of echoes that are due to reflection (as first described by <NPL> and <NPL>), permeable to low-coherence light used in optical coherence tomography (OCT), radiolucent such that it is permeable to various forms of electromagnetic radiation (for example, is permeable to ECoG (electrocorticographic) signals), and transparent for ideal visualization necessary for brain lead placement, catheter positioning, etc. This allows for the critical transmission of vital imaging with minimal distortion, such as direct visual inspection of the brain, ultrasound waves for brain pathology detection, low-coherence light used in optical coherence tomography (OCT), and wireless signal communication (i.e., electroencephalography or ECoG), which is essential for various neuromodulation devices. Another clear material that may be readily used in accordance with the present reconstructive cranial implant is cubic zirconium or plastic.

The optical clarity of the implant body <NUM> is important in that it provides for the provision of high optical clarity allowing for optical links connecting the external environment to the surface of the brain (for example, transmitting between the cortex and the other side of the reconstructive cranial implant). Visualization devices such as high-definition cameras, ultrasound probes, or optical coherence tomography (OCT) imaging devices may therefore be used in conjunction with the reconstructive cranial implant.

Still further, the implant body is constructed of a material allowing for imaging of the brain through the reconstructive cranial implant, for example, via ultra-sound or optical coherence tomography. It is known that clear PMMA will provide the ability to permit ultra-sound imaging of the brain therethrough so long as it is manufactured without additives that might function to block the radio waves of the imaging device.

While the majority of the peripheral edge <NUM> of the implant body defines a generally continuously curved surface shaped and dimensioned to sit within the resected portion of the skull, a mating segment <NUM> of the peripheral edge <NUM> of the implant body <NUM> is shaped and dimensioned for a mating coupling with the shunt plug housing <NUM>.

In particular, and considering the curved shape of the shunt plug housing <NUM> at the first end <NUM> thereof, the mating segment <NUM> is formed with a relatively concave profile shaped and dimensioned to mate with the first end <NUM> of the shunt plug housing <NUM>. At a central portion 920c of the mating segment, a further concave cut-out <NUM> is formed. The concave cut-out <NUM> is positioned for alignment with the first access passageways <NUM> and provides an opening for the ventricular catheter <NUM> for positioning a described above.

In practice, installation would be accomplished in a manner similar to the embodiments discussed above.

As with the embodiment disclosed above, various features may be integrated into the clear custom cranial implant in an effort to enhance the functionality thereof. While these features are described herein as individual embodiments, it is appreciated they may be combined in various combinations as the needs of a patient dictate.

While the shunt plug housing and implant body of the various embodiments disclosed above are made of various materials as discussed above, it is contemplated, the shunt plug housing and/or implant body implant body could be of a multi-material construction with the use of different materials in different elements of the shunt plug housing and/or implant body so as to expand the functionality thereof.

For example, and with reference to <FIG> (not part of the present invention), the shunt plug housing <NUM> includes a central body member <NUM> made of rigid sonolucent PMMA and a flexible perimeter member <NUM> made of porous polyethylene. Such a construction provides medical practitioners with a large sonolucent area for transcranioplasty ultrasound as provided by the central body member <NUM> and a malleable perimeter as provided by the perimeter member <NUM> that optimizes a smooth transition between the implant perimeter and the native skull.

In accordance with another embodiment as shown with reference to <FIG>, the shunt plug housing <NUM> includes a central body member <NUM> made of cubic zirconium (or any other rigid sonolucent material) and a flexible perimeter member <NUM> made of expanded polytetrafluoroethylene (EPTFE), silicon, or other malleable material.

In accordance with yet another embodiment as shown in <FIG> (not part of the present invention), the shunt plug housing <NUM> could be a different composition of the same material, with the different compositions being selected to enhance sonolucency and aesthetic fixation. For example, the central body member <NUM> of the shunt plug housing <NUM> could be rigid sonolucent PMMA while the flexible perimeter member <NUM> of the shunt plug housing <NUM> could be PMMA with elastomer additives that change the material properties of the shunt plug housing from rigid to malleable. In this way, the implant could have an optimal smooth transition from the perimeter of the implant to the native skull.

Claim 1:
A cerebral spinal fluid shunt plug (<NUM>, <NUM>), comprising:
a shunt plug housing (<NUM>, <NUM>) including an upper surface (<NUM>, <NUM>), a lower surface (<NUM>), continuous side walls extending between the upper surface (<NUM>, <NUM>) and the lower surface (<NUM>), as well as about the periphery of the shunt plug housing, a shunt valve recess (<NUM>, <NUM>) being formed in the upper surface (<NUM>, <NUM>) of the shunt plug housing (<NUM>, <NUM>) and either an intracranial monitoring recess (<NUM>) with an access hole (<NUM>) or a window recess (<NUM>) with a central access hole (<NUM>) being formed in the upper surface (<NUM>, <NUM>) of the shunt plug housing (<NUM>, <NUM>),
the shunt plug housing (<NUM>, <NUM>) further including passageways allowing the shunt valve recess (<NUM>, <NUM>) to communicate with an exterior of the shunt plug housing, the access holes (<NUM>, <NUM>) or passageways being shaped and dimensioned to allow for connection of a ventricular catheter and a peritoneal catheter with the shunt valve housed within the recess (<NUM>, <NUM>) of the shunt plug housing (<NUM>, <NUM>), the housing (<NUM>, <NUM>) being shaped and dimensioned for positioning within a physician formed cranial hole (<NUM>) in a manner allowing the upper surface (<NUM>, <NUM>) of the housing (<NUM>, <NUM>) to be substantially flush with an outer surface of a skull and a projection (434p, 734p) along the lower surface being positioned within the cranial hole; and
a window or an intracranial monitoring device (<NUM>) shaped and dimensioned for respectively positioning within either the window recess (<NUM>) or the intracranial monitoring recess (<NUM>) of the shunt plug housing (<NUM>, <NUM>).