BURR HOLE PLUG DESIGNS
A burr hole plug comprises a plug base including a flange configured for being mounted around a burr hole, an aperture through which an elongated medical device may pass, and tabs configured for extending within the cranial burr hole to center the plug base relative to the cranial burr hole. The burr hole plug further comprises a retainer configured for being mounted within the aperture of the plug base to secure the medical device. A method may comprise locating the plug base within a burr hole, such that the tabs are disposed within the burr hole to center the plug base relative to the cranial burr hole, introducing the elongated medical device through the cranial burr hole and into the brain tissue of the patient, mounting the retainer within the aperture of the plug base, and actuating the retainer to secure the medical device.
The present application claims the benefit under 35 U.S.C. § 119 to U.S. Provisional Patent Application Ser. No. 60/983,099, filed Oct. 26, 2007. The foregoing application is hereby incorporated by reference into the present application in its entirety.
FIELD OF THE INVENTIONThe present inventions relate to apparatus for securing elongated medical devices, such as catheters or leads, within a cranial burr hole.
BACKGROUND OF THE INVENTIONDeep brain stimulation (DBS) and other related procedures involving implantation of electrical stimulation leads within the brain of a patient are increasingly used to treat disorders, such as Parkinson's disease, dystonia, essential tremor, seizure disorders, obesity, depression, restoration of motor control, and other debilitating diseases via electrical stimulation via stimulation of one or more target sites, including the ventrolateral thalamus, internal segment of globus pallidus, substantia nigra pars reticulate, subthalamic nucleus (STN), or external segment of globus pallidus. DBS has become a prominent treatment option for many disorders, because it is a safe, reversible alternative to lesioning. For example, DBS is the most frequently performed surgical procedure for the treatment of advanced Parkinson's Disease. There have been approximately 30,000 patients world-wide that have undergone DBS surgery. Consequently, there is a large population of patients who will benefit from advances in DBS treatment options.
During DBS procedures, at least one burr hole is meticulously cut through the patient's cranium so as not to damage the brain tissue below, a large stereotactic targeting apparatus is mounted to the patient's cranium, and a cannula is scrupulously positioned towards the target site in the brain. A stimulation lead is then introduced through the cannula, through the burr hole, and into the parenchyma of the brain, such that one or more electrodes located on the lead are strategically placed at a target site in the brain of the patient. Once the lead is properly positioned, the portion of the lead exiting the burr hole is subcutaneously routed underneath the patient's scalp to an implantable pulse generator (IPG) implanted in the patient at a site remote from the burr hole (e.g., the patient's shoulder or chest region). Further details discussing the treatment of diseases using DBS are disclosed in U.S. Pat. Nos. 6,845,267, 6,845,267, and 6,950,707, which are expressly incorporated herein by reference.
Significantly, it is crucial that proper location and maintenance of the lead position be accomplished in order to continuously achieve efficacious therapy. This is especially so with DBS applications, in which cases, the target site (or sites) that is intended for electrical stimulation is about the size of a pea and is located deep within the patient's brain. Thus, lead displacements of less than a millimeter may have a deleterious effect on the patient's therapy. Therefore, it is important that that the electrode(s) of the lead be accurately located at the target site and that such electrode(s) be securely maintained at the target site during and after implantation of the lead. In addition, it is important that the burr hole be sealed around the stimulation lead to prevent infection or leakage of cerebrospinal fluid.
To address these issues, a cranial burr hole plug is installed within the burr hole during the implantation procedure to hold the stimulation lead in place, as well as to seal the burr hole. Typically, the burr hole plug is composed of a multitude of components, including a ring-shaped base, a retainer, and a cap, that are integrated together to form the burr hole plug.
In particular, before the stimulation lead is introduced through the burr hole, the ring-shaped plug base is placed about the burr hole, and is then permanently mounted to the patient's cranium using conventional means, such as screws. The stimulation lead is then introduced through the plug base and into the parenchyma of the brain. Notably, any displacement of the portion of the lead exiting the burr hole will result in the translation of the electrodes positioned in the brain relative to the target site, thereby requiring the lead to be repositioned—a time-consuming process.
Thus, once the lead is properly located at the tissue site, the retainer is installed within the plug base (typically in an interference arrangement, such as a snap-fit arrangement) to temporarily secure the lead, thereby preventing migration of the lead relative to the target site during subsequent manipulation of the proximal end of the lead and installation of the cap. In one exemplary embodiment, the retainer comprises a disk having a slot for receiving the lead and a clamping mechanism that can be rotated within the slot towards a mating surface on the disk to frictionally clamp the received lead therebetween. The clamping mechanism may have one or more locking mechanisms that can engage or disengage complementary locking mechanisms on the disk to prevent rotation of the clamping mechanism. The portion of the stimulation lead exiting the retainer can then be bent downward towards the plane of the disk into a recess formed in the plug base, and the cap can be installed onto the plug base over the retainer to permanently secure the lead within the recess, as well as to seal the burr hole. Further details regarding these types of burr hole plugs are disclosed in U.S. Patent Publication No. 2002/0156372.
It can thus be appreciated from the foregoing that the burr hole plug serves as the platform for the entire DBS system, and therefore, it is important for this component to be robust, well-designed, and easy to use. Importantly, the burr hole plug should be designed such that lead migration is minimized during installation of the burr hole plug. While prior art burr hole plugs have proven to be useful in the DBS context, there are still improvements that can be made.
As one example, prior art burr hole plugs are typically composed of biocompatible and non-corrosive material, such as a plastic (e.g., polypropylene or polycarbonate), which although less durable than other materials, is compatible with MRI, and unlike titanium, will not distort the MRI. To ensure that the burr hole plug is durable enough during its installation within the burr hole, the plug base typically has a closed architecture (closed ring). Because of this, as well as the location of the lead guidance equipment at the proximal end of the lead, the plug base must be mounted within or around the burr hole prior to delivery of the stimulation lead through the burr hole. While this, in itself, does not create a problem, if the lead is inadvertently delivered into the patient's brain before the plug base is located at the burr hole, the lead will need to be backed out of the burr hole and the lead delivery process initiated again. Also, because prior art plug bases are composed of a single piece, there is a risk that the plug base may fracture if the plug base is anchored to tightly to the cranium of the patient, especially if the bottom surface of the plug base does not match the curvature of the cranium.
Because the retainer installed within the plug base is also composed of plastic material, the retainer will typically deform somewhat during its installation within the plug base and during manipulation of the clamping mechanism to stabilize the lead. In addition, because the clamping mechanism will deform somewhat along its length when clamped against the stimulation lead, an unequal force may be applied along the clamping mechanism, thereby weakening the retention force applied to the lead. Also, because of the relatively weak composition of the retainer, the clamping force between it and the mating surface of the disk is limited, thereby limiting the lead retention force of the clamping mechanism. Furthermore, because the application of a downward force is typically necessary to unlock and allow the clamping mechanism to rotate relative to the disk, such downward force may cause the clamping mechanism to be bent too far down, thereby permanently deforming or breaking it. In addition, since burr hole plugs are typically composed of biocompatible polymers that are extremely lubricious, particularly when wetted, the coefficient of friction of the retention surface of the clamping mechanism, as well as the mating surface of the disk, may be relatively low. As a result, the lead may migrate when only a moderate amount of tensile force is applied to it.
As another example of a problem suffered from prior art burr hole plugs, the retainer may rotate within the plug base, potentially resulting in the inadvertent movement of the stimulation lead from the target site. Such rotation of the retainer mechanism may typically occur in response to the manipulation of the clamping mechanism, and in particular, a downward force applied to the clamping mechanism that causes partial disengagement between the retaining disk to which the clamping mechanism is mounted and the plug base, and a lateral force applied to the clamping mechanism that causes the disengaged disk to rotate within the plug base.
As still another example, many DBS systems have evolved from a single lead (unilateral) system to double lead (bilateral) systems; for example, one lead is used to perform STN stimulation, while another lead is used to perform thalamus stimulation. Other DBS systems may use a recording lead to record brain signals that are then fed back to the IPG to control the stimulation applied to the target site by the stimulation lead(s). However, prior art burr hole plugs are not designed to stabilize more than one stimulation lead at time. This is because the slot within the disk can only secure leads that exit the burr hole along the diameter of the disk, although the leads may be offset from the diameter. Thus, despite the fact that the target sites stimulated and/or recorded by the leads may be adjacent to each other, multiple burr holes, each accommodating a stimulation lead and burr hole plug, are typically formed in the cranium of the patient when multiple stimulation leads are used. By creating multiple burr holes, the risk to the patient, time in the operating room (which also increases patient risk), the materials and staff needed in the operating room, and cost of the procedure are all increased, so a burr hole plug that can accommodate multiple leads through one burr hole is preferred.
As yet another example, it is preferable that the portion of the stimulation lead exiting the burr hole be disposed at an angle perpendicular to the length of the slot of the retaining disk when bent down towards the plane of the disk, so that the lead does not move along the slot when tensed. However, because the recess of the plug base in which the lead is seated may be located obliquely (as opposed to perpendicular) to the slot, it may be difficult to bend the lead perpendicular to the slot towards the base recess if the lead support mechanism is not perfectly oriented relative to the plug base. In addition, rotation of the lead support mechanism relative to the base while the lead is seated within the base recess may cause the lead to be displaced from the target site.
In yet another example, the plug base must be securely held in place while anchoring it to the cranium via screws. The retainer must also be mounted within the plug base, such that the retaining disk is properly seated within the plug base without disturbing the position of the lead, which is precariously held by the stereotactic targeting apparatus. However, due to the diminutive size of the burr hole plug components, they are difficult to position, manipulate, and handle. This, in combination with the limited working space between the targeting apparatus and the burr hole, makes it quite difficult to visualize and correctly install the plug within the burr hole and stabilize the lead. While the surgeon is installing the components of the burr hole plug, there is a risk of foreign objects (screws, tools, debris, etc.) falling into the exposed burr hole, as well as slippage of tools within the burr hole. Prior art tools, which stabilize plug bases while covering the burr hole and holding/aligning the screws used to anchor the plug bases, can be utilized. However, the screws often pop-out of these tools unintentionally and do not always screw into the cranium at the correct angle.
Thus, installation of the burr hole plug without disturbing the lead position is nearly an impossible task without specialization of the tools and/or burr hole plug that can center the plug base while it is anchored to the patient's skull and securely hold and mount the retainer to the plug base. Typically, the surgeon may use a special tool that engages the retainer, such that it can be navigated and positioned within the plug base, and then pressed downward to snap-fit it into the plug base. However, this installation tool only engages the retaining disk at one location. Thus, it is possible that the disk may become skewed or tilted while attempting to install it within the plug base, or worse yet, given the spring force stored in the disk, it may be launched from the surgical site.
In yet another example, prior art burr hole plugs are designed to be used with stimulation leads having one size. That is, the dimension between the retaining surface of the clamping device and the mating surface of the disk when the clamping device is in the locked position is designed to be slightly less than the diameter of the lead. If the diameter of the actual lead used with the burr hole plug is smaller than this intended, the retention force applied to the lead by the clamping mechanism will not be sufficient. If the diameter of the actual lead used with the burr hole plug is greater than this intended diameter, too much force will need to be applied to the lead in order to place the clamping mechanism within the locking position, thereby potentially damaging the retainer and/or the lead.
As yet another example, once the plug base is mounted to the patient's cranium via screws, it is difficult to adjust the position of the plug base if it is desired. Also, due to the relatively large size of the stereotactic targeting apparatus, there is often little working space available between the targeting apparatus and the burr hole to anchor the plug base to the cranium of the patient.
There, thus, remains a need for improved burr hole plug designs.
SUMMARY OF THE INVENTIONIn accordance with a first aspect of the present inventions, a cranial burr hole plug is provided. The burr hole plug comprises a plug base including a flange configured for being mounted around a cranial burr hole, an aperture through which an elongated medical device exiting the burr hole may pass, and a plurality of tabs (e.g., at least three tabs) configured for extending within the cranial burr hole to center the plug base relative to the cranial burr hole. The plug base aperture has a suitable shape (e.g., circular) and a suitable dimension (e.g., equal to or less than 25 mm). In one embodiment, the plug base includes an open slot configured for laterally receiving the medical device. In another embodiment, the tabs are disposed on a bottom surface of the plug base flange and are coincident with the aperture. While the present inventions should not be so limited in their broadest aspects, the use of tabs to center the plug base relative to the cranial burr hole obviates the need to use a special tool to perform the centering function.
The burr hole plug further comprises a retainer configured for being mounted within the aperture of the plug base to secure the medical device. In one embodiment, the retainer is configured for being removably mounted within the aperture of the plug base. In another embodiment, the plug base includes at least one inner annular ledge configured for supporting the retainer when mounted within the aperture of the plug base. In still another embodiment, the retainer further includes a retainer support (e.g., a disk), a slot formed in the retainer support for receiving the medical device, and a clamping mechanism configured for applying a clamping force to the medical device received within the slot. The clamping mechanism may include a clamping bar configured for engaging the medical device, and a locking element configured for locking the clamping bar relative to the retainer support when the medical device is secured.
The burr hole plug may comprise other components in addition to the plug base and retainer. For example, the burr hole plug may comprise fasteners configured for anchoring the plug base to a cranium of a patient, and a cap configured for being mounted to the plug base over the retainer. The plug base may have an exit groove configured for seating the medical device, in which case, the cap may be configured for firmly securing the medical device within the exit groove when the cap is mounted to the plug base.
In accordance with a second aspect of the present inventions, a method of performing a medical procedure on a patient is provided. The method comprises providing a plug base including a flange, an aperture, and a plurality of tabs. In one method, the tabs are equally spaced apart around the circumference of the cranial burr hole. In another method, the tabs are disposed on a bottom surface of the plug base flange. The method further comprises locating a plug base within a cranial burr hole, such that the flange is disposed about the cranial burr hole, and the tabs are disposed within the burr hole to center the plug base relative to the cranial burr hole.
The method further comprises introducing an elongated medical device (e.g., an electrical lead) through the cranial burr hole and into the brain tissue of the patient, wherein the medical device exits the cranial burr hole through the aperture of the plug base. In one method, the plug base includes an open slot, in which case, the method may further comprising laterally introducing the medical device within the slot. In this case, the plug base may be mounted around the cranial burr hole after the medical device is introduced through the burr hole into the brain tissue of the patient. The method further comprises mounting a retainer within the aperture of the plug base, and actuating the retainer to secure the medical device. In one method, the plug base includes an open slot, in which case, the method may further comprise laterally introducing the medical device within the slot. In this case, the plug base may be mounted around the cranial burr hole after the medical device is introduced through the burr hole into the brain tissue of the patient. The method may also comprise mounting a cap to the plug base over the retainer.
Other and further aspects and features of the invention will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the invention.
In accordance with a third aspect of the present inventions, a cranial burr hole plug is provided. The burr hole plug comprises a plug base including a flange configured for being mounted around a cranial burr hole, and an aperture through which an elongated medical device exiting the burr hole may pass. The plug base aperture has a suitable shape (e.g., circular) and a suitable dimension (e.g., equal to or less than 25 mm). In one embodiment, the plug base includes an open slot configured for laterally receiving the medical device. In an optional embodiment, the plug base includes a plurality of tabs configured for extending within the cranial burr hole to center the plug base relative to the cranial burr hole. The tabs may, e.g., be disposed on a bottom surface of the plug base flange, and may be coincident with the plug base aperture.
The burr hole plug further comprises a retainer configured for being mounted within the aperture of the plug base to secure the medical device, such that the retainer is at least partially recessed within the burr hole. In one embodiment, the flange has a bottom surface and the retainer is configured for extending below the bottom surface of the flange. While the present invention should not be so limited in their broadest aspects, the recession of the retainer into the burr hole allows the profile (i.e., height) of the burr hole plug to be reduced. In one embodiment, the retainer is configured for being removably mounted within the aperture of the plug base.
In another embodiment, the plug base includes at least one inner annular ledge configured for supporting the retainer when mounted within the aperture of the plug base. In this case, the plug base may further include at least one annular flange extending from the inner annular ledge(s) below a bottom surface of the flange. The use of the annular flange(s) allows the retainer to be further recessed into the burr hole, thereby further decreasing the profile of the burr hole plug. In still another embodiment, the retainer further includes a retainer support (e.g., a disk), a slot formed in the retainer support for receiving the medical device, and a clamping mechanism configured for applying a clamping force to the medical device received within the slot. The clamping mechanism may include a clamping bar configured for engaging the medical device, and a locking element configured for locking the clamping bar relative to the retainer support when the medical device is secured.
In accordance with a fourth aspect of the present inventions, a method of performing a medical procedure on a patient is provided. The method comprises mounting a plug base around the cranial burr hole, the plug base including a flange and an aperture, and introducing an elongated medical device (e.g., an electrical lead) through the cranial burr hole and into the brain tissue of the patient, wherein the medical device exits the cranial burr hole through the aperture of the plug base. In one method, the plug base includes an open slot, in which case, the method may further comprising laterally introducing the medical device within the slot. In this case, the plug base may be mounted around the cranial burr hole after the medical device is introduced through the burr hole into the brain tissue of the patient. The method further comprises mounting a retainer within the aperture of the plug base, such that the retainer is at least partially recessed within the burr hole, thereby providing the stated advantages above. The method further comprises actuating the retainer to secure the medical device.
Other and further aspects and features of the invention will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the invention.
In accordance with a fifth aspect of the present inventions, a cranial burr hole plug is provided. The burr hole plug comprises a split plug base configured for being mounted around a cranial burr hole. The split plug base includes an aperture through which an elongated medical device exiting the burr hole may pass. The plug base aperture has a suitable shape (e.g., circular) and a suitable dimension (e.g., equal to or less than 25 mm). The plug base includes a plurality of base portions configured for being demated from each other to separate the plug base, and for being mated to each other to integrate the plug base. Although the present inventions should not be so limited in their broadest aspects, the use of the split plug base allows the plug base to be conveniently mounted around the burr hole after the stimulation lead has already been introduced through the burr hole.
In one embodiment, plug base only includes two base portions that are both annular. The base portions may be configured for mating together in an interference arrangement. For example, one of the base portions may have a recess, and the other of the base portions may have a protuberance configured for being located within the recess to mate the base portions together. As one example, the recess may be disposed on an upper surface of the one base portion, and the protuberance may laterally extend from the other base portion, such that the other base portion can be dropped down on the one base portion to mate them together. In an optional embodiment, the plug base comprises at least one element (e.g., a pin) that firmly couples the base portions together. In this case, the element(s) can be configured for being shearing off after the base portions are demated from each other, so that the base portions can then be mated together without obstruction from the element(s).
The burr hole plug further comprises a retainer configured for being mounted within the aperture of the plug base to secure the medical device. In one embodiment, the retainer is configured for being removably mounted within the aperture of the plug base. In another embodiment, the plug base includes at least one inner annular ledge configured for supporting the retainer when mounted within the aperture of the plug base. In still another embodiment, the retainer further includes a retainer support (e.g., a disk), a slot formed in the retainer support for receiving the medical device, and a clamping mechanism configured for applying a clamping force to the medical device received within the slot. The clamping mechanism may include a clamping bar configured for engaging the medical device, and a locking element configured for locking the clamping bar relative to the retainer support when the medical device is secured.
The burr hole plug may comprise other components in addition to the plug base and retainer. For example, the burr hole plug may comprise fasteners configured for anchoring the plug base to a cranium of a patient, and a cap configured for being mounted to the plug base over the retainer. The plug base may have an exit groove configured for seating the medical device, in which case, the cap may be configured for firmly securing the medical device within the exit groove when the cap is mounted to the plug base.
In accordance with an sixth aspect of the present inventions, a method of performing a medical procedure on a patient is provided. The method comprises introducing an elongated medical device (e.g., an electrical lead) through a cranial burr hole of the patient and into the brain tissue of the patient, such that an exposed portion of the medical device exits the cranial burr hole. The method further comprises locating a first plug base portion adjacent one side of the exposed portion of the medical device, locating a second plug base portion adjacent another side of the exposed portion of the medical device, and mating the first and second plug base portions together (e.g., in an interference arrangement) to form a plug base having an aperture through which the exposed portion of the medical device extends. The method further comprises anchoring the plug base around the cranial burr hole, mounting a retainer within the aperture of the plug base, and actuating the retainer to secure the medical device. The method may further comprise anchoring the plug base to the cranium of the patient. In one method, the first and second plug base portions are mated together while the first plug base portion is located on one side of the cranial burr hole. In another method, the first and second plug base portions are mated together by disposing the second plug base portion over the first plug base portion. In still another method, a cap is mounted to the plug base over the retainer.
Other and further aspects and features of the invention will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the invention.
In accordance with a seventh aspect of the present inventions, a cranial burr hole plug is provided. The burr hole plug comprises a plug base configured for being mounted around a cranial burr hole. The plug base includes an aperture through which an elongated medical device exiting the burr hole may pass. The plug base aperture has a suitable shape (e.g., circular) and a suitable dimension (e.g., equal to or less than 25 mm). In one embodiment, the plug base includes an open slot configured for laterally receiving the medical device.
The burr hole plug further comprises a retainer configured for being mounted within the aperture of the plug base. In one embodiment, the retainer is configured for being removably mounted within the aperture of the plug base. In another embodiment, the plug base includes at least one inner annular ledge configured for supporting the retainer when mounted within the aperture of the plug base. The retainer includes a retainer support (e.g., a disk), a slot formed in the retainer support for receiving the medical device, and a clamping mechanism having a clamping bar and a slidable flange slidably engaged with the retainer support to laterally slide the clamping bar to secure the medical device received within the slot. In one embodiment, the retainer support has a fixed clamping bar on one side of the slot opposite the clamping bar, and the clamping bar is configured for clamping the medical lead against the fixed clamping bar. While the present invention inventions should not be so limited in their broadest aspects, the specific design of the retainer provides a robust clamping mechanism even if the retainer is composed of a relatively low durable and pliable material.
The retainer may include a recess formed in the retainer support along which the slidable flange is slidably engaged. In this case, the retainer may further include a pair of C-channels disposed on opposite sides of the recess, wherein a pair of opposing edges of the slidable flange are respectively received within the C-channels. In another embodiment, the clamping bar has a clamping surface with relief features, e.g., to increase the retention force applied to the medical device. In still another embodiment, the slot is an open slot configured for laterally receiving the medical device. In yet another embodiment, the retainer support includes first and second portions, and the retainer further includes a hinge coupled to the first and second flange portions, whereby the first and second flange portions can be alternately hinged open to laterally receive the medical lead within the slot and hinged closed to encompass the medical lead within the slot.
The clamping mechanism may include a locking element configured for locking the clamping bar relative to the retainer support when the medical device is secured. In this case, the retainer support may have a complementary locking element with which the locking element of the clamping mechanism is configured for engaging. In another embodiment, the retainer support may have a plurality of complementary locking mechanisms with which the locking element of the clamping mechanism is configured for selectively engaging, such that the clamping bar is configured for being locked relative to the retainer support at different positions.
The clamping mechanism may also have a resilient arm on which the locking element is disposed, and the arm may be configured for being actively flexed to release the locking element from the complementary element. In one example, the locking element is a tab and the complementary locking mechanism is a stop, in which case, the clamping mechanism may be configured for being placed in a locked position by abutting the tab against the stop, and for being placed in an unlocked position by flexing the arm to disengage the tab from the stop. The tab and the stop may have abutment surfaces that are angled relative to a plane of the flange, e.g., to facilitate placing the clamping mechanism in the unlocked position. The clamping mechanism may have a recess configured for receiving the tip of a tool to flex the resilient arm. In this case, the recess may be angled relative to a plane of the retainer support, such that a portion of a downward force applied to the recess is transferred in a direction away from the slot along the plane of the retainer support. Thus, placement of the clamping mechanism in the unlocked position may be further facilitated. The recess may be located closer to a center of the retainer support than a circumference of the retainer support, so that, e.g., force applied to the circumference of the retainer support that may otherwise reduce the disengagement force between the retainer and the plug base may be minimized. The clamping mechanism may further comprise a stop affixed to the slidable flange for limiting the flexing of the resilient arm, thereby minimizing the chance that the resilient arm will be broken or otherwise damaged.
The burr hole plug may comprise other components in addition to the plug base and retainer. For example, the burr hole plug may comprise fasteners configured for anchoring the plug base to a cranium of a patient, and a cap configured for being mounted to the plug base over the retainer. The plug base may have an exit groove configured for seating the medical device, in which case, the cap may be configured for firmly securing the medical device within the exit groove when the cap is mounted to the plug base.
In accordance with an eighth aspect of the present inventions, a method of performing a medical procedure on a patient is provided. The method comprises introducing an elongated medical device (e.g., an electrical lead) through a cranial burr hole of the patient and into the brain tissue of the patient. The method further comprises mounting a plug base around the cranial burr hole, such that the medical device extends through an aperture of the plug base, and mounting a retainer within the aperture of the plug base. The retainer includes a retainer support, a slot formed in the retainer support, and a clamping mechanism having a clamping bar and a slidable flange slidably engaged with the retainer support. The method further comprises receiving the medical device into the slot (e.g., laterally), and sliding the slidable flange relative to the retainer support to laterally slide the clamping bar, thereby securing the medical device received within the slot. The method may further comprise mounting a cap to the plug base over the retainer.
In one method, the retainer support has a fixed clamping bar on one side of the slot opposite the clamping bar, such that the clamping bar clamps the medical lead against the fixed clamping bar. In another method, the clamping mechanism has a locking element, in which case, the method further comprises actuating the locking element to lock the clamping bar relative to the retainer support when the medical device is secured. The method may further comprise actuating the locking element to unlock the clamping bar relative to the retainer support when the medical device is secured. In this case, the clamping mechanism may have a resilient arm on which the locking element is disposed, and the method may comprise actively flexing the resilient arm to actuate the locking element to unlock the clamping bar relative to the retainer support when the medical device is secured. In another method, the locking element is actuated to lock the clamping bar at different positions.
Other and further aspects and features of the invention will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the invention.
In accordance with an ninth aspect of the present inventions, a cranial burr hole plug is provided. The burr hole plug comprises a plug base configured for being mounted around a cranial burr hole. The plug base includes an aperture through which an elongated medical device exiting the burr hole may pass. The plug base aperture has a suitable shape (e.g., circular) and a suitable dimension (e.g., equal to or less than 25 mm). In one embodiment, the plug base includes an open slot configured for laterally receiving the medical device.
The burr hole plug further comprises a retainer configured for being mounted within the aperture of the plug base to secure the medical device. The retainer includes at least one exit groove (e.g., a plurality of grooves circumferentially distributed on the retainer) configured for seating the medical device, such that the medical device is radially directed towards the plug base. The exit groove(s) may, e.g., be configured for seating the medical device when it is bent at a ninety degree angle relative to an axis of the burr hole. Although the present inventions should not be so limited in their broadest aspects, the use of exit grooves on the retainer, itself, allows the medical device to exit the retainer at an angle that minimizes movement of the medical device within the retainer.
In one embodiment, the retainer is configured for being removably mounted within the aperture of the plug base. In another embodiment, the plug base includes at least one inner annular ledge configured for supporting the retainer when mounted within the aperture of the plug base. In still another embodiment, the retainer further includes a retainer support (e.g., a disk), a slot formed in the retainer support for receiving the medical device, and a clamping mechanism configured for applying a clamping force to the medical device received within the slot. The clamping mechanism may include a clamping bar configured for engaging the medical device, and a locking element configured for locking the clamping bar relative to the retainer support when the medical device is secured.
The burr hole plug may comprise other components in addition to the plug base and retainer. For example, the burr hole plug may comprise fasteners configured for anchoring the plug base to a cranium of a patient, and a cap configured for being mounted to the plug base over the retainer. The plug base may have an exit groove configured for seating the medical device, in which case, the cap may be configured for firmly securing the medical device within the exit groove when the cap is mounted to the plug base.
In accordance with a tenth aspect of the present inventions, a method of performing a medical procedure on a patient is provided. The method comprises introducing an elongated medical device (e.g., an electrical lead) through a cranial burr hole of the patient and into the brain tissue of the patient, mounting a plug base around a cranial burr hole, such that the medical device extends through an aperture of the plug base, and mounting a retainer within the aperture of the plug base. The method further comprises actuating the retainer to secure the medical device, and radially directing the medical device towards the plug base by seating the medical device within an exit groove of the retainer, thereby providing the stated advantages above.
In one method, the medical device is bent at an angle relative to an axis of the burr hole (e.g., a ninety degree angle) prior to seating the medical device within the exit groove. In another method, one of a plurality of exit grooves of the retainer are selected, and the medical device is seated within the selected exit groove. The method further comprises mounting a cap to the plug base over the retainer, such that the medical device is secured between the plug base and the cap. In one method, the medical device is secured within the exit groove when the cap is mounted to the plug base over the retainer. In another method, the medical device is secured within a slot formed in the retainer, and the exit groove is radially oriented perpendicular to the slot.
Other and further aspects and features of the invention will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the invention.
In accordance with a eleventh aspect of the present inventions, a cranial burr hole plug is provided. The burr hole plug comprises a plug base configured for being mounted around a cranial burr hole. The plug base includes an aperture through which an elongated medical device exiting the burr hole may pass. The plug base aperture has a suitable shape (e.g., circular) and a suitable dimension (e.g., equal to or less than 25 mm). In one embodiment, the plug base includes an open slot configured for laterally receiving the medical device.
The burr hole plug further comprises a retainer configured for being mounted within the aperture of the plug base. In one embodiment, the retainer is configured for being removably mounted within the aperture of the plug base. In another embodiment, the plug base includes at least one inner annular ledge configured for supporting the retainer when mounted within the aperture of the plug base. The retainer further includes first and second slidable clamping mechanisms configured for securing the medical devices therebetween within the aperture of the plug base. While the present inventions should not be so limited in their broadest aspects, the use of two slidable clamping mechanisms conveniently facilitates the securing of more than one medical device within a single cranial burr hole. For example, the first and second slidable clamping mechanisms can be configured for securing the medical devices along any one of a plurality of chords of the aperture of the plug base.
In one embodiment, the retainer further includes a retainer support (e.g., a disk) and a slot formed in the retainer support for receiving the medical devices. In one embodiment, the slot may be open slot configured for laterally receiving the medical device. In another embodiment, the retainer support includes first and second portions, and the retainer further includes a hinge coupled to the first and second flange portions, whereby the first and second flange portions can be alternately hinged open to laterally receive the medical lead within the slot and hinged closed to encompass the medical lead within the slot.
The first and second clamping mechanisms may be slidably engaged with the retainer support to secure the medical devices received within the slot. In this case, each of the first and second clamping mechanisms may have a clamping bar and a slidable flange slidably engaged with the retainer support to laterally slide the clamping bar to secure the medical devices received within the slot. At least one of the clamping bars has a clamping surface with relief features, e.g., to increase the retention force applied to the medical device. The retainer may further include first and second recesses formed in the retainer support on opposite sides of the slot, and the slidable flanges of the first and second clamping mechanisms may be slidably engaged within the respective recesses. In this case, the retainer may include first and second pairs of C-channels, each pair disposed on opposite sides of the respective recess, such that a pair of opposing edges of each slidable flange are respectively received within the respective C-channels.
The burr hole plug may comprise other components in addition to the plug base and retainer. For example, the burr hole plug may comprise fasteners configured for anchoring the plug base to a cranium of a patient, and a cap configured for being mounted to the plug base over the retainer. The plug base may have an exit groove configured for seating the medical device, in which case, the cap may be configured for firmly securing the medical device within the exit groove when the cap is mounted to the plug base.
In accordance with a twelfth aspect of the present inventions, a method of performing a medical procedure on a patient is provided. The method comprises introducing at least one elongated medical device (e.g., an electrical lead) through a cranial burr hole of the patient and into the brain tissue of the patient. The method further comprises mounting a plug base around a cranial burr hole, such that the medical device extends through an aperture of the plug base, and mounting a retainer within the aperture of the plug base. The retainer includes first and second clamping mechanisms. The method further comprises sliding the first and second clamping mechanisms secure the medical device(s) therebetween, thereby providing the same advantages described above. In one method, the first and second clamping mechanisms secure the medical devices along an off-center chord of the aperture of the plug base. In another method, the retainer further includes a retainer support and a slot formed in the retainer support for receiving the medical devices, in which case, the method may further comprise receiving the medical device(s) into the slot, wherein the first and second clamping mechanisms are slid relative to the retainer support to secure the at least one medical device received within the slot. The method may further comprise mounting a cap to the plug base over the retainer.
Other and further aspects and features of the invention will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the invention.
In accordance with a thirteenth aspect of the present inventions, a cranial burr hole plug is provided. The burr hole plug comprises a plug base configured for being mounted around a cranial burr hole. The plug base includes an aperture through which an elongated medical device exiting the burr hole may pass. The plug base aperture has a suitable shape (e.g., circular) and a suitable dimension (e.g., equal to or less than 25 mm). In one embodiment, the plug base includes an open slot configured for laterally receiving the medical device.
The burr hole plug further comprises a retainer including a retainer support (e.g., a semi-circular flange) configured for being mounted within the aperture of the plug base, and a clip configured for mating with the retainer support (e.g., in an interference arrangement) to secure the medical device between the clip and a clamping surface of the retainer support. In one embodiment, the retainer support is configured for being removably mounted within the aperture of the plug base. In another embodiment, the plug base includes at least one inner annular ledge configured for supporting the retainer support when mounted within the aperture of the plug base. In still another embodiment, the retainer support includes a pair of C-channels, and the clip includes a pair of resilient arms configured for slidably engaging the opposing C-channels. In this case, the clip may include a pair of tabs respectively disposed on ends of the arms, and the tabs may be configured for respectively engaging ends of the opposing C-channels to lock the clip relative to the retainer support. The arms may further be configured for being displaced toward each other away from the rails to disengage the tabs from the opposing C-channels.
The burr hole plug may comprise other components in addition to the plug base and retainer. For example, the burr hole plug may comprise fasteners configured for anchoring the plug base to a cranium of a patient, and a cap configured for being mounted to the plug base over the retainer. The plug base may have an exit groove configured for seating the medical device, in which case, the cap may be configured for firmly securing the medical device within the exit groove when the cap is mounted to the plug base.
In accordance with a fourteenth aspect of the present inventions, a method of performing a medical procedure on a patient is provided. The method comprises introducing an elongated medical device (e.g., an electrical lead) through a cranial burr hole of the patient and into the brain tissue of the patient. The method further comprises mounting a plug base around a cranial burr hole, such that the medical device extends through an aperture of the plug base, mounting a retainer support within the aperture of the plug base, and mating a clip to the retainer support (e.g., an interference arrangement) to secure the medical device between the clip and a clamping surface of the retainer support. In one method, the retainer support includes a pair of opposing C-channels, the clip includes a pair of resilient arms, and the clip is mated with the retainer support by sliding the arms within the C-channels. In this case, the clip may include a pair of tabs respectively disposed on ends of the arms, and the arms can be slid within the opposing C-channels until the tabs respectively engage ends of the opposing C-channels, thereby locking the clip relative to the retainer support. The arms may be displaced toward each other away from the C-channels to disengage the tabs from the opposing C-channels. One method further comprises mounting a cap to the plug base over the retainer.
Other and further aspects and features of the invention will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the invention.
The drawings illustrate the design and utility of preferred embodiments of the present invention, in which similar elements are referred to by common reference numerals. In order to better appreciate how the above-recited and other advantages and objects of the present inventions are obtained, a more particular description of the present inventions briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
Turning first to
To secure the stimulation lead 12 (or leads) and to prevent infection and leakage of cerebral spinal fluid, the system 10 further comprises a burr hole plug 16 mounted to the cranium 6 around the burr hole 5 of the patient 1. The stimulation lead 12 extends from the burr hole 5, through the burr hole plug 16, to a location external to the cranium 6. Details discussing the structure and function of various embodiments of the burr hole plug 16 will be discussed in further detail below.
The DBS system 10 further comprises a neurostimulator 17, such as an implantable pulse generator (IPG), radio frequency (RF) receiver-stimulator, or any other device coupled to and capable of delivering electrical stimulation energy to the stimulation lead 12 in a controlled and therapeutic manner. The neurostimulator 17 may be generally implanted in a surgically made pocket in the torso of the patient (e.g., the chest or shoulder region). The neurostimulator 17 may, of course, also be implanted in other locations of the patient's body. The DBS system 10 further comprises a lead extension 19, which may be suitably connected to the proximal end of the stimulation lead 12 and subcutaneously advanced underneath the scalp 7 of the patient 1 to the neurostimulator implantation site, thereby facilitating the location of the neurostimulator 17 away from the exit point of the stimulation lead 12 (i.e., the burr hole 5). In alternative embodiments, the neurostimulator 17 may be directly implanted on or within the cranium 6 of the patient 1, as described in U.S. Pat. No. 6,920,359, which is expressly incorporated herein by reference. In this case, the lead extension 19 may not be needed. After implantation, the neurostimulator 17 is used to provide the therapeutic stimulation under control of the patient 1. The system 10 may include external components, such as a patient handheld programmer, a clinician programming station, and an external charger (all not shown), the details of which will not be described herein for purposes of brevity.
In should be understood that, while the invention lends itself well to applications in DBS, the invention, in its broadest aspects, may not be so limited. For example, the stimulation lead 12 (or leads) can be delivered within regions of the brain other than a deep brain structure, e.g., within or on the surface of the cerebral cortex. In addition, electrical leads, other than stimulation leads, may be delivered within the head 4 of the patient 1. For example, an electrical recording lead can be delivered into the head 4 of the patient 1 via the burr hole 5 to sense brain signals, either alone or in conjunction with a stimulation lead. Further, elongated medical devices other than electrical leads; for example, drug delivery catheters or needles, may be delivered into the head 4 of the patient 1 via the burr hole 5. Thus, it can be appreciated that the burr hole plugs described herein can be used with any elongated medical device intended to be delivered through a burr hole 5 within the cranium 6 of a patient 1 for any therapeutic and/or diagnostic purpose.
Referring now to
Referring further to
To ensure that the ring-shaped body 24 is centered relative to the burr hole, the plug base 18 further comprises a plurality of self-centering tabs 32 configured for extending within the burr hole. In the illustrated embodiment, the tabs 32 are disposed on the bottom surface 30 of the ring-shaped body 24, so that the tabs 32 do not obstruct the passage of the stimulation lead through the plug base aperture 26. Notably, because the tabs 32, as opposed to a continuous cylindrical flange, are independently flexible, the plug base 18 can be centered within burr holes that are slightly smaller than the circumference defined by the tabs 32. Thus, the plug base 18 can be used with differently sized burr holes.
The plug base 18 preferably includes at least three tabs 32 equidistantly spaced around the aperture 26 in order to maximize the centering function. The tabs 32 are preferably arranged in a manner such that they fit tightly against the inner surface of the circumference of the burr hole so as to avoid any movement of the plug base 18 relative to the burr hole. In this case, the tabs 32 will be coincident with the plug base aperture 26 (assuming that the aperture 26 is of the same size and shape as the burr hole). The tabs 32 are designed to be permanently disposed on the ring-shaped body 24, such that the tabs 32 will remain located within the burr hole after implantation. The tabs 32 may be suitably disposed onto the ring-shaped body 24, for example, by molding the tabs 32 and body 24 as a unibody design. Significantly, the self-centering tabs 32 conveniently and quickly allow the plug base 18 to be centered relative to the burr hole without the aid of a special centering tool.
In the illustrated embodiment, the plug base 18 is permanently anchored to the cranium of the patient. To this end, the plug base 18 includes two fastening holes 34 formed within the ring-shaped body 24 for respectively receiving anchoring fasteners, such as, e.g., screws, pins, spikes, tabs, or buttons. Alternatively, other means of anchoring the plug base 18 to the cranium of the patient, such as, e.g., adhesion, can be used. Relief structures (not shown) may be added to the bottom surface 30 of the ring-shaped body 24 and the outer surfaces of the tabs 32 to prevent rotational movement between the plug base 18 and the burr hole prior to permanent anchoring to the cranium. Such relief structures may include, e.g., a rough sandpaper-like surface, notches, bumps, horizontal or vertical ribs or threads, etc.
The plug base 18 further comprises a plurality of lead exit grooves 36 (in this case, four equally spaced grooves) configured for seating the stimulation lead. In particular, the portion of the stimulation lead exiting the burr hole through the aperture 26 of the plug base 18 (i.e., the proximal end of the stimulation lead) can be bent down at a perpendicular angle and seated within one of the lead exit grooves 36 of the plug base 18, such that the proximal end of the stimulation lead lies generally parallel to the exterior surface of the cranium. As will be described in further detail below, the stimulation lead will be firmly secured within the selected exit groove 36 when the cap 22 is mounted to the plug base 18.
The plug base 18 further comprises a cap pop-out recess 38 located at an inner edge 40 of the ring-shaped body 24 adjacent the aperture 26, and a plurality of cap locking recesses 42 (in this case, a pair of oppositely disposed locking recesses). As will be described in further detail below, a tool can be inserted into the cap pop-out recess 38 to remove the previously mounted cap 22 from the plug base 18, and the cap locking recesses 42 can receive corresponding cap locking tabs (described below) for facilitating mounting of the cap 22 to the plug base 18. The plug base 18 also comprises at least one inner annular ledge 44 (in this case, three equally spaced annular ledges) configured for supporting the retainer 20 when mounted within the plug base aperture 26. To this end, the annular ledges 44 are disposed on an inner surface 46 (best shown in
Referring back to
In the embodiment illustrated in
In an alternative embodiment, a split plug base 78 illustrated in
In the illustrated embodiment, opposing ends 84, 86 of the first annular body portion 80 respectively include a female coupling element 92 and a male coupling element 94, and opposing ends 88, 90 of the second annular body portion 82 respectively include a male coupling element 96 and a female coupling element 98. The male and female elements 92-98 match each other, such that the ends 84, 88 of the annular body portions 80, 82 can be mated together by receiving the male coupling element 96 of the second annular body portion 82 into the female coupling element 92 of the first annular body portion 80, and the ends 86, 90 of the annular body portions 80, 82 can be mated together by receiving the male coupling element 94 of the first annular body portion 80 into the female coupling element 98 of the second annular body portion 82. Alternatively, both male coupling elements 94, 96 may be located on the opposing ends 84, 86 of the first annular body portion 80, and both female coupling elements 92, 98 may be located on the opposing ends 88, 90 of the second annular body portion 82, or vice versa, with similar results.
In the embodiment illustrated in
Thus, it can be appreciated that the annular body portions 80, 82 can be demated from each other to accommodate a stimulation lead that has already been introduced through a burr hole, and then mated together to integrate the plug base 18, which can then be anchored to the cranium of the patient. It should also be appreciated that, since the plug base 18 is composed of several independent components that can move relative to each other, there is less of a chance of fracturing the plug base 78 when it is anchored to the cranium of the patient.
Even though the plug base 78 is designed to be separated into two pieces, it may still be desirable to alternatively maintain the plug base 78 as a single piece (i.e., as a prior art plug base), for example, when the plug base 18 is to be mounted to the cranium of the patient prior to introducing the stimulation lead through the burr hole. To this end, the plug base 78 comprises additional coupling elements that firmly couple the annular body portions 80, 82 together. In the illustrated embodiment, these coupling elements take the form of complementary pins 100 and recesses (not shown) that firmly engage each other, such that the mated first and second annular body portions 80, 82 act as a unibody design until they are intentionally separated. Once the annular body portions 80, 82 are demated from each other, the pins 100 can be broken off or otherwise removed, so that the second annular body portion 82 can be lowered down on to the first annular body portions 80 when they are mated together without any hindrance from the pins 100. Alternatively, the coupling elements can simply take the form of bonding material or other connection that can be easily fractured to demate the annular body portions 80, 82 from each other.
In alternative embodiments, the complementary body portions 80, 82 may be jointed together using a tool. For example, referred to
Referring to
The outer diameters of the plug bodies 110, 112 are substantially equal to the diameter of the burr hole, such that the plug base 108 can be disposed entirely within the burr hole. The outer diameter of the seal 114, when uncompressed (
Thus, it can be appreciated that rotation of the screws 124 in one direction using a tool, such as a screwdriver, will cause the plug bodies 110, 112 to be displaced toward each other, which will cause the annular boss 122 of the lower plug body 112 to move into the annular recess 120 of the upper plug body 110 to compress the seal 114 in the vertical direction, thereby expanding the seal 114 in the horizontal direction to sealingly mount the plug base 108 within the burr hole. Rotation of the screws 124 in the opposite direction will cause the plug bodies 110, 112 to be displaced away from each other, which will cause the annular boss 122 of the lower plug body 112 to move out of the annular recess 120 of the upper plug body 110 to allow the seal 114 to expand in the vertical direction, thereby allowing the seal 114 to compress in the horizontal direction to release the plug base 18 from within the burr hole. Although only two screws 124 are shown, more than two screws (e.g., four), can be used to ensure substantially uniform compression of the seal 114 around its circumference.
In an alternative embodiment, a plug base 128 illustrated in
While the fasteners that displace the upper and lower plug bodies to compress the seal have been described as screws, other types of fasteners can be used, such as complementary coupling elements that are fit together in an interference arrangement. For example, as illustrated in
In another alternative embodiment illustrated in
Referring to
In the illustrated embodiment, the retaining support 160 comprises a disk 164 and an open lead slot 166 formed in the disk 164 for laterally receiving the stimulation lead, thereby allowing the retainer 20 to be mounted within the plug base aperture 26 after the stimulation lead has been introduced through the burr hole. As best shown in
The annular ledges 44 are displaced from the top surface of the plug base 18 a dimension that causes at least a portion of the retainer 20, and in particular the disk 164, below the bottom surface 30 of the ring-shaped plug body 24. As a result, at least a portion of the disk 164 will be recessed within the burr hole when mounted within the plug base 18, thereby lowering the profile of the portion of the burr plug 16 above the burr hole. In the case where annular flanges 45 are provided, as illustrated in
As discussed above, the retainer 20, and in particular the retainer support 160 comprises a plurality of sun-dial ticks 174 that engage the ramps 48, thereby limiting rotation of the retainer 20 within the plug base aperture 26. In this case, the sun-dial ticks 174 take the form of radially extending ribs that are distributed about the circumference on the top surface 171 of the disk 164. Notably, as the circumferential distance between the sun-dial ticks 174 decreases, the rotational movement of the retainer 20 within the aperture 26 of the plug body 24 will be incrementally decreased to the same extent. In this illustrated embodiment, the circumferential spacing between the sun-dial ticks 174 is approximately 24 degrees, and therefore, the rotation of the retainer 20 will be limited to 24 degrees.
The retainer support 160 comprises a fixed clamping bar 176 disposed on an inner edge of the disk 164 adjacent one side of the lead slot 166. The clamping mechanism 162 operates in conjunction with the fixed clamping bar 176 to secure the stimulation lead therebetween, as will be described in further detail below. As best shown in
The clamping mechanism 162 comprises a movable clamping bar 184 and a flange 186 slidably engaged with the disk 164 to laterally slide the movable clamping bar 184 relative to the disk 164 and selectively secure the stimulation lead received within the lead slot 166 or release the stimulation lead received within the lead slot 166. The movable clamping bar 184 extends parallel to the lead slot 166 opposite to the fixed clamping bar 176 on the disk 164, such that a clamping surface 188 of the movable clamping bar 184 is configured for clamping the stimulation lead against a clamping surface 190 of the clamping bar 176. In the illustrated embodiment, the clamping surfaces 188, 190 of the respective clamping bar 184 and clamping bar 176 are ribbed in order to provide localized gripping of the stimulation lead, thereby increasing the lead retention force. The clamping mechanism 162 further comprises an angled flange 192 located at the end of the movable clamping bar 184, thereby preventing the stimulation lead from being located past the movable clamping bar 184 at the end of the slot 166 where it could potentially be wedged between the clamping mechanism 162 and the end of the slot 166.
In the illustrated embodiment, the flange 186 is U-shaped and includes a pair of legs 194 extending perpendicularly from the movable clamping bar 184 away from the lead slot 166 and a cross bar 196 that extends between the legs 194 in a direction generally parallel to the lead slot 166. The U-shaped flange 186 further comprises rails 198 that extend along the outer surface of the legs 194. The sliding arrangement between the flange 186 of the clamping mechanism 162 and the disk 164 of the retainer support 160 is provided between the legs 194 of the U-shaped flange 186 and the C-channels 180 of the retainer support 160. In particular, the U-shaped flange 186 is received within the recess 178, with the rails 198 of the flange 186 slidably received within the C-channels 180 in a closely toleranced relationship, so that the flange 186, and thus the movable clamping bar 184, can be smoothly moved back and forth in a lateral direction (i.e., perpendicular to the lead slot 166).
The clamping mechanism 162 is configured for being placed between an unlocked (or open) position (
Thus, the clamping mechanism 162 can be placed from the unlocked position (or open position) (
The clamping mechanism 162 can be placed from the locked position (
Significantly, the relative dimensions between the resilient arm 200, locking tab 202, and recess stop 182 are selected, such that the abutment surface 208 of the locking tab 202 becomes coincident with the abutment surface 210 of the recessed stop 182 as the stimulation lead becomes secured between the clamping surface 188 of the movable clamping bar 184 and the clamping surface 190 of the fixed clamping bar 176. In the manner, firm clamping of the stimulation lead is ensured without damaging the stimulation lead.
To facilitate manipulation of the clamping mechanism 162 relative to the disk 164, the clamping mechanism 162 comprises a recess 212 formed on the bearing surface 204 of the locking tab 202 for receiving a tool that can be used to flex the resilient arm 200 in order to transition the clamping mechanism 162 from the locked position into the unlocked position. The tool can also be received within the recess 212 to slide the movable clamping bar 184 towards or away from the fixed clamping bar 176 to secure or release the stimulation lead. It should be noted that the recess 212 is closer to the center of the disk 164 than the circumference of the disk 164. Thus, when a downward force applied to the recess 212, any force applied to the circumference of the disk 164, which may otherwise disengage, or weaken the engagement between, the sun-dial ticks 174 on the top surface 171 of the disk 164 from the ramps 48 on the inner surface 46 of the ring-shaped plug body 24, will be minimized or decreased.
To further facilitate placing the clamping mechanism 162 from the locked position into the unlocked position, the bearing surface 204 of the locking tab 202, and thus, the recess 212, may be angled (as best shown in
To prevent the resilient arm 200 from fatiguing or breaking, the clamping mechanism 162 further comprises a stop 214 that is affixed to the U-shaped flange 186 to prevent the resilient arm 200 from bending past a certain point, as best shown in
In an alternative embodiment, the retainer support 160 has a plurality of complementary locking mechanisms with which a locking element of the clamping mechanism 162 is configured for selectively engaging, such that the movable clamping bar 184 is configured for being located relative to the disk 164 at different positions. For example, as illustrated in
Notably, the retainer support 160 and the clamping mechanism 162 may have additional features that maximize the clamping force applied to the stimulation lead. For example, the retainer 20, including the retainer support 160 and the clamping mechanism 162, can be composed of PEEK, thereby substantially increasing the durability of the retainer 20, even in view of the open architecture of the retainer support 160. Since deformation of the movable clamping bar 184 will be substantially decreased by the PEEK composition, the clamping force will be more uniformly distributed along the movable clamping bar 184, thereby securing the stimulation lead in a more reliable manner. The reduced deformation of the U-shaped flange 186 and disk 164 will also allow the clamping mechanism 162 to slide relative to the retainer support 160 in a more reliable and robust manner.
In addition, the clamping surfaces 188, 190 of the movable clamping bar 184 and/or fixed clamping bar 176 may be provided with any one of a variety of relief features. For example, the relief features may include horizontal ridges or bars (
The above relief features will increase the retention force of the movable clamping bar 184 and/or fixed clamping bar 176 by altering the coefficient of friction, increasing compression, “biting” into the lead, creating edges to catch the lead, increasing surface area, locally increasing clamping force, deformation of the lead into surface recesses, etc. Combinations of relief features in multiple directions on the movable clamping bar 184 and/or fixed clamping bar 176 can prevent the lead from moving in multiple directions (e.g., along the lead axis and along the face of the movable clamping bar 184 and/or fixed clamping bar 176 perpendicular to the lead axis). Relief structures can be provided on the clamping surfaces 188, 190 of both the movable clamping bar 184 and the fixed clamping bar 176 to operate in combination with each other to neck or otherwise provide a tortuous path for the lead. For example, the relief structures on the clamping surfaces 188, 190 may be staggered or interlocking (
While the burr hole plug 16 illustrated in
Because there are two exit grooves 232, the direction in which the stimulation lead exits the retainer 230 may be selected. In an alternative embodiment, a plurality of fastening exit grooves (not shown) can be provided on each side of the clamping slot 166, such that the stimulation lead may be placed and perpendicularly bent downward at multiple locations along the clamping slot 166. In another alternative embodiment, each fastening exit groove 232 may be slid back and forth in a direction parallel to the clamping slot 166, such that the stimulation lead may be placed and perpendicularly bent downward at multiple locations along the clamping slot 166.
While the previous retainers 20, 230 include single slidable clamping mechanisms, retainers constructed in accordance with the present inventions may include more than one slidable clamping mechanism. For example, referring to
The retainer 240 differs from the retainer 20 in that it comprises two slidable clamping mechanisms 252, each including a movable clamping bar 254 and a flange 256 slidably engaged with the disk 244 to laterally slide the movable clamping bar 254 relative to the disk 244 and selectively secure the stimulation lead received within the lead slot 246 or release the stimulation lead received within the lead slot 246. The movable clamping bars 254 extend parallel to the lead slot 246 opposite each other, such that clamping surfaces 258 (only one shown) of the respective clamping bars 254 are configured for clamping the stimulation lead against each other. Like the clamping surfaces 188, 190 of the respective clamping bar 184 and clamping bar 176 discussed above with respect to the retainer 20, the clamping surfaces 258 of the clamping bars 254 may be ribbed or comprise other relief features (not shown), thereby increasing the lead retention force. In addition, each clamping mechanism 252 may alternatively include a U-shaped flange, resilient arm, locking tab, and an arm stop (all not shown) similar to the U-shaped flange 186, resilient arm 200, locking tab 202, and arm stop 220 described above with respect to the retainer 20.
The retainer 240 may include features formed into the disk 244 for accommodating the slidable clamping mechanisms 252. For example, the retainer support 242 may include recesses with opposing C-channels (not shown) similar to the recess 178 and opposing C-channels 180 described above with respect to the retainer 20. The retainer support 242 may also include recessed stops (not shown) similar to the recessed stop 182 described above with respect to the retainer 20 for respectively accommodating locking elements of the clamping mechanism 252. Preferably, the clamping bars 254 of the clamping mechanisms 252 can be variably locked in different positions, e.g., by utilizing ratchets 220, as illustrated in
Thus, it can be appreciated that instead of securing the stimulation lead between a slidable clamping bar and a fixed clamping bar, the slidable clamping mechanisms 252 may both be slid relative to the disk 244 in order to secure a stimulation lead between the movable clamping bars 254. Significantly, because both clamping mechanisms 252 are slidable relative to the disk 244, a plurality of stimulation leads can be secured along any one of a plurality of different chords C1-C4 of the plug base aperture 26, as illustrated in
Although the retainer 240 includes two slidable clamping mechanisms, retainers constructed in accordance with the present inventions may include more than two slidable clamping mechanisms. For example, referring to
In either embodiment, each flange 251 is slidably engaged with the disk 245 to laterally slide the concave tip 253 radially inward relative to the disk 245 and selectively secure the stimulation lead received within the lead slot 247 (
In an alternative embodiment illustrated in
While the previous retainers 20, 230, 240 include fixed open lead slots for receiving stimulation leads, retainers may have leads slots that alternately open and close. For example, as illustrated in
Other types of lead retainers are also contemplated by the present inventions. For example, referring to
The clip 284 comprises a transverse member 292 and a clamping bar 294 disposed on the transverse member 292. Thus, when the clip 294 is mated with the retaining support 292, the stimulation lead will be secured between a clamping surface 296 of the retaining support 282 (and in particular the fixed clamping bar 288) and a clamping surface 298 of the clip 284 (and in particular the movable clamping bar 294). The clip 284 is configured for mating with the retaining support 282 in an interference arrangement. To this end, the clip 284 has a pair of opposing resilient arms 300 extending from the transverse member 292. The arms 300 are configured for slidably engaging the respective C-channels 290 located on the semi-circular flange 286. Thus, the clip 284 can be mated with the retaining support 282 by inserting the respective arms 300 of the clip 284 into the C-channels 290. Notably, the resiliency of the arms 300 allows them to flex outward as they are inserted into the C-channels 290, and once fully inserted, they flex back to the normal shape to grasp the C-channels 290.
The clip 284 further comprises a pair of locking elements, and in particular, a pair of tabs 302 respectively disposed on the ends of the arms 300, such that when the arms 300 are fully inserted into the C-channels 290, the tabs 302 engage the ends of the opposing C-channels 290 to lock the clip 284 relative to the retaining support 282. The arms 300 may be displaced toward each other away from the C-channels 290 to disengage the locking tabs 302 from the opposing C-channels 290, thereby allowing the clip 284 to be removed from the retaining support 282. The clip 284 further comprises a pair of stops 304 located between the transverse member 292 and the respective resilient arms 300 that abut the fixed clamping bar 288 and the front of the C-channels 290 when the clip 284 is mated with the retaining support 282. In this manner, the clamping bar 294 of the clip 284 is prevented from moving past a certain point, thereby preventing damage to the stimulation lead.
Referring to
The cap 22 comprises a circular lid-type body 310 having a rim 312 sized and shaped to be disposed within the plug base aperture 26 and resting on the retaining disk 164. To accommodate the locking ramps 48 located on the inner surface 46 of the plug base body 24, the cap 22 includes a plurality of recesses 314 located on the exterior surface of the rim 312. The number of circumferential spacing of the recesses 314 matches the number and spacing of the locking ramps 48, such that each ramp 48 is received into a corresponding recess 314 when the cap 22 is mounted to the plug base 18.
The cap 22 further comprises a plurality of winged tabs 316 (in this case, two) configured for being received into the corresponding locking recesses 42 located on the plug base body 24 (shown in
The cap 22 further comprises a plurality of lead clamp grooves 320 (in this case, four) located on the bottom surface of the cap 22 and extending through the rim 312. The number and circumferential spacing of the lead clamp grooves 320 matches the number of spacing of the lead exit grooves 36 located on the plug base 18 (shown in
Having described the burr hole plug 16, various tools that can be used to install a burr hole plug into a burr hole will now be described. Referring to
The burr hole cover 332 has a lid-shape having an aperture geometrically similar to the aperture 26 of the plug base 16 (in this case, circular) and is sized to fit into and completely cover the plug base aperture 26. The lip of the burr hole cover 332 may rest on annular ledges of the plug base 16 in the same manner as the retainer rests on the annular ledges described above. In this manner, any potential for debris, such as screws, falling through the plug base aperture 26 and into the burr hole, or accidental slippage of tools, such as a screwdriver, into the burr hole, is minimized. In an optional embodiment, the burr hole cover 332 includes features, such as snaps, keyways, set screws, adhesive, suction ports, threads, etc., that engage the plug base 16 in a manner that secures the burr hole cover 332 within the aperture 26 and also allows the burr hole cover 332 to be removed from the plug base 16 after the plug base 16 is anchored to the cranium of the patient. Alternatively, the tool 330 can be shaped in a manner that positions its center of gravity, such that the tool 330 remains on a flat surface without fastening it to the plug base 16 (i.e., it does not fall over). In the case where the plug base 16 does not include self-centering tabs, the tool 330 may include centering tabs (not shown) that extend downward from the cover 332, through the aperture 26 in the plug base 16, and into the burr hole, in order to center both the plug base 16 relative to the burr hole.
The handle 334 laterally extends away from the burr hole cover 332, and thus the burr hole, as to not interfere with the placement, visualization, alignment, and anchoring of the plug base 16 to the burr hole. The handle 334 is shaped to more ergonomically allow the physician to grasp the handle. For example, the profile of the handle 334 flares out as the handle 334 laterally extends from the burr hole cover 332 to allow the handle 334 to be more easily gripped. In addition, the handle 334 includes relief features (in this case, grooves in a criss-cross pattern) to facilitate gripping of the handle 334, which may be important in a slippery environment (such as a physician wearing wet gloves). In an alternative embodiment illustrated in
In the illustrated embodiment, the burr hole cover 304 includes a pair of recesses 338 formed in its upper surface to accommodate the laterally extending screw holder arms 336. The screw holder arms 336 include collars 340 that are spaced from each other, such that they respectively align with the screw holes 34 located on the plug base 18 when the burr hole cover 332 is mounted within the plug base aperture 26. Thus, the screws 15 may be accurately inserted through the collars 340 and aligned with the screw holes 34 (shown in
Referring to
The burr hole cover 352 has a cylindrical shape having a diameter substantially the same as the diameter of the aperture 26 of the plug base 18 (in this case, circular) and is sized to cover the plug base aperture 26. In this manner, any potential for debris, such as screws, falling through the plug base aperture 26 and into the burr hole, or accidental slippage of tools, such as a screwdriver, into the burr hole, is minimized. The tool 350 includes a plurality of centering tabs 358 extending downward from the burr hole cover 352, such that the centering tabs 358 rest against the inner surface 46 of the plug base 18 when the burr hole cover 352 is mounted within the plug base aperture 26. In the illustrated embodiment, two pairs of centering tabs 358 (only one pair shown) are circumferentially disposed opposite each other.
The tool 350 further includes various features that engage the plug base 18 in a manner that secures the burr hole cover 352 within the aperture 26 and also allows the burr hole cover 352 to be removed from the plug base 18 after the plug base 18 is anchored to the cranium of the patient. In particular, the tool 350 comprises upper grasping tabs 360 and lower grasping tabs 362 arranged in manner, such that when the tool 350 is disposed within the aperture 26 of the plug base 18, the thickness of the plug base 18 is disposed between the grasping tabs 360, 362, so that the plug base 18 is grasped from above and below; that is the upper grasping tabs 360 have lower surfaces that frictionally grasp the top surface 28 the plug base 18, and the lower grasping tabs 362 have upper surfaces that frictionally grasp the bottom surface 30 of the plug base 18. The upper surfaces of the lower grasping tabs 362 may be slightly convex, so that they mate perfectly with the slightly concave bottom surface 30 of the plug base 18.
In the illustrated embodiment, there are two upper grasping tabs 360 (only one shown) radially extending from, and circumferentially disposed on opposite sides of, the outer surface of the burr hole cover 352, and two pairs of lower grasping tabs 362 (only one pair shown) extending radially extending from, and circumferentially disposed on opposite sides of, the respective pairs of centering tabs 358. Each pair of lower grasping tabs 362 circumferentially straddles the respective upper grasping tab 360 to firmly engage a circumferential portion of the plug base 18 therebetween. Thus, it can be appreciated that the grasping tabs 360, 362 allow the tool 350 to grasp and pick up the plug base 18, as well as to prevent the tool 350 from being separating from the plug base 18 when anchoring the plug base 18 to the cranium of the patient.
The tool 350 also comprises a plurality of rotational alignment tabs 364 radially extending from the outer surface of the burr hole cover 352 in order to rotationally align the screw holder mechanisms 356 with the fastening holes 34 in the plug base 18, as well as to prevent the tool 350 from rotating or spinning in the aperture 26 of the plug base 18. In the illustrated embodiment, two rotational alignment tabs 364 are circumferentially disposed opposite each other, and are sized and shaped for being firmly disposed within the cap locking recesses 42 in the plug base 18. Alternatively, the tool 350 may include rotational alignment tabs (not shown) that are sized and shaped for being firmly disposed within the lead exit grooves 36 of the plug base 18.
The handle 354 is shaped such that the physician may ergonomically grasp it to prevent the tool 350 and the plug base 18 from moving when the plug base 18 is being anchored to the cranium of the patient. The handle 354 may have any one of a variety of shapes. In the embodiment illustrated in
Referring further to
Each screw alignment mechanism 356 includes an insert 374 disposed within the upper bore 370 of the collar 368. The insert 374 is composed of a flexible and pliable material, e.g., silicone. The insert 374 takes the form of a ring- or gasket-like structure that firmly holds and centers the respective screw 15 within the collar 368. In particular, as best shown in
As best shown in
In an alternative embodiment illustrated in
As best shown in
In another alternative embodiment illustrated in
Referring next to
The distal ends of the fingers 434, and thus the contact points 436 on the top surface 171 of the retaining disk 164, are spaced from each other in a manner that substantially distributes any downward force applied by the tool 430 across the plane of the retaining disk 164 when mounted within the plug base aperture 26. In the embodiment illustrated in
Preferably, this interference arrangement is sufficient enough to provide a firm engagement between the tool 430 and the retainer 20, but should be capable of being overcome after the retainer 20 is mounted within the plug base 18, so that the tool 430 can be easily removed from the retainer 20, while leaving the retainer 20 firmly mounted within the plug base 18. For example, as illustrated in
In one preferred embodiment, the fingers 434 are resiliently flexible, so that they store a spring force when engaged with the recesses 436 on the retaining disk 164. In this case, the spacing between the distal ends of the fingers 434, in the absence of any lateral force, is slightly less than the spacing between the recesses 436 on the retaining disk 164. In this manner, the fingers 434 will act as biased springs when engaged with the recesses 436, thereby providing an additional grasping force that strengthens the engagement with the retainer 20. That is, the fingers 434 will slightly spread out when located within the recesses 436, thereby creating a spring force that laterally urges or biases the fingers 434 inward within the recesses 436 to create a frictional force that facilitates engagement between the fingers 434 and the recesses 436. The fingers 434, as well as the handle 432, may be composed of a suitable resilient material, such as, polypropylene, polycarbonate, etc. Alternatively, the tool 430 may be provided with a separate spring-like mechanism 440 engaged between the fingers 434, as illustrated in
Referring to
In the illustrated embodiment, two pegs 456 are provided on the C-shaped flange 454, one located on one end of the C-shaped flange 454 and the other one located near the center of the C-shaped flange 454. Optionally, a third peg (not shown) can be provided on the other end of the C-shaped flange 454. The pegs 456 are spaced from each other, such that they engage with contact points, and in particular, corresponding recesses or holes 458 (only one show in
As can be appreciated from
To this end, and as best shown in
Notably, the handle 452 is angled relative to the C-flange 454 in order to facilitate the manipulation, navigation, and placement of the retainer 20 in tight spaces. That is, due to its angle relative to the plane of the retainer 20 that it supports, the movement of the handle 452 may not be obstructed by equipment immediately above the burr hole. To this end, the distal end of the handle 452 to which the collar 462 is mounted has a bend (e.g., a 45 degree or a 60 degree angle between the collar 462 and the handle 452) to effect the angling of the handle 452 relative to the C-flange 454. The distal end of the handle 452 may optionally be made malleable to allow the physician to create the optimum angle for insertion of the retainer 20 into the plug base aperture 26. The proximal end of the tool 450 may be designed to perform another function, such as locking or unlocking the clamping mechanism 162 or popping the retainer 20 out from the plug base 18. For example, as illustrated in
Referring to
In the illustrated embodiment, the tip 484 takes the form of a spring mechanism, and in particular a spring clip, that includes a pair of parallel arms 486 that move toward each other from a relaxed position to a compressed position in response to a compressive force, and move away from each other from the compressed position to the relaxed position in the absence of the compressive force. The tool 480 comprises a collar 488 formed at the distal end of the handle 482 for retaining the tip 484. In particular, the collar 488 includes a receptacle 490 that receives the arms 486 of the tip 484 in an interference arrangement. Specifically, the collar 488 is split or forked to form a pair of opposing annular flanges 492 that respectively receive the arms 486 of the tip 484 therein. The tip 484 can be arranged as an insert that can be passed through a distal aperture 494 of the receptacle 490. Once inserted within the receptacle 494, the resiliency of the tip 484 will cause the arms 486 to be urged radially outward away from each other into firm contact with the respective annular flanges 492, thereby mounting the tip 484 to the handle 482. In this state, the tip 484 will be partially radially compressed. When the tip 484 is inserted into the recess 486 of the retaining disk 164, the tip 484 will be further radially compressed within the recess 486 to create the aforementioned frictional fit. To prevent the tip 484 from axially moving out of the receptacle 490 during such compression, the tip 484 further comprises a pair of radially outward tabs 496 respectively formed on the ends of the arms 484. The distal end of the handle 482 further includes corresponding recesses 498 for receiving and holding the tabs 496 therein.
Having described the structure and function of the burr hole plug 16 and tools used with burr hole plugs into a burr hole, a method of mounting the burr hole plug 16 into a burr hole will now be described. Referring first to
Next, as illustrated in
After the plug base 18 has been anchored to the cranium 6 and the stimulation lead 12 introduced through the burr hole 5 and properly located adjacent the target site, the retainer 20 is mounted within the plug base aperture 26, as illustrated in
Once the retainer 20 (or retainer 230) is firmly mounted within the plug base aperture 26, the retainer 20 is actuated to secure the stimulation lead 12 within the plug base aperture 26, as illustrated in
Notably, if the retainer 280 illustrated in
After the stimulation lead 12 (or leads) is secured within the plug base aperture 26, the stimulation lead 12 is radially directed towards the plug base 18 by bending the stimulation lead 12 at an angle (e.g. perpendicular) relative to an axis of the burr hole 5 and seating the stimulation lead 12 within one of the lead exit grooves 36 located on the plug base 18, as illustrated in
Although particular embodiments of the present inventions have been shown and described, it will be understood that it is not intended to limit the present inventions to the preferred embodiments, and it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present inventions. Thus, the present inventions are intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the present inventions as defined by the claims.
Claims
1. A cranial burr hole plug, comprising:
- a plug base including a flange configured for being mounted around a cranial burr hole, an aperture through which an elongated medical device exiting the burr hole may pass, and a plurality of tabs configured for extending within the cranial burr hole to center the plug base relative to the cranial burr hole; and
- a retainer configured for being mounted within the aperture of the plug base to secure the medical device.
2. The burr hole plug of claim 1, wherein the aperture of the plug base is circular.
3. The burr hole plug of claim 1, wherein the greatest dimension of the aperture in equal to or less than 25 mm.
4. The burr hole plug of claim 1, wherein the plug base includes an open slot configured for laterally receiving the medical device.
5. The burr hole plug of claim 1, wherein the plurality of tabs comprises at least three tabs.
6. The burr hole plug of claim 1, wherein the tabs are disposed on a bottom surface of the plug base flange.
7. The burr hole plug of claim 2, wherein the tabs are coincident with the aperture.
8. The burr hole plug of claim 2, wherein the retainer is configured for being removably mounted within the aperture of the plug base.
9. The burr hole plug of claim 2, wherein the plug base includes at least one inner annular ledge configured for supporting the retainer when mounted within the aperture of the plug base.
10. The burr hole plug of claim 2, wherein the retainer further includes a retainer support and a slot formed in the retainer support for receiving the medical device.
11. The burr hole plug of claim 10, wherein the retainer includes a clamping mechanism configured for applying a clamping force to the medical device received within the slot.
12. The burr hole plug of claim 11, wherein the clamping mechanism includes a clamping bar configured for engaging the medical device, and a locking element configured for locking the clamping bar relative to the retainer support when the medical device is secured.
13. The burr hole plug of claim 11, wherein the retainer support is a disk.
14. The burr hole plug of claim 1, further comprising fasteners configured for anchoring the plug base to a cranium of a patient.
15. The burr hole plug of claim 1, further comprising a cap configured for being mounted to the plug base over the retainer.
16. The burr hole plug of claim 14, wherein the plug base has an exit groove configured for seating the medical device, and wherein the cap is configured for firmly securing the medical device within the exit groove when the cap is mounted to the plug base.
17. A method of performing a medical procedure on a patient, comprising:
- providing a plug base including a flange, an aperture, and a plurality of tabs;
- locating a plug base within a cranial burr hole, such that the flange is disposed about the cranial burr hole, and the tabs are disposed within the burr hole to center the plug base relative to the cranial burr hole;
- anchoring the plug base relative to the cranial burr hole;
- introducing an elongated medical device through the cranial burr hole and into the brain tissue of the patient, wherein the medical device exits the cranial burr hole through the aperture of the plug base;
- mounting a retainer within the aperture of the plug base; and
- actuating the retainer to secure the medical device.
18. The method of claim 17, wherein the tabs are equally spaced apart around the circumference of the cranial burr hole.
19. The method of claim 17, wherein the tabs are disposed on a bottom surface of the plug base flange.
20. The method of claim 17, wherein the medical device is an electrical lead.
21. The method of claim 17, wherein the plug base includes an open slot form in the plug base flange, the method further comprising laterally introducing the medical device within the slot.
22. The method of claim 21, wherein the plug base is mounted around the cranial burr hole after the medical device is introduced through the burr hole into the brain tissue of the patient.
23. The method of claim 17, further comprising mounting a cap to the plug base over the retainer.
24.-171. (canceled)
Type: Application
Filed: Oct 24, 2008
Publication Date: Apr 30, 2009
Inventors: Courtney Lane (Ventura, CA), Jesse Geroy (North St. Paul, MN), James C. Makous (Santa Clarita, CA), Todd Whitehurst (Santa Clarita, CA), Matthew Flowers (Irvine, CA), John Michael Barker (Ventura, CA), Terry Ferrell (Lino Lakes, MN), John Swoyer (Andover, MN), Brett Schleicher (Valencia, CA), Jeff Gagnon (Champlin, MN), Andrew Digiore (Santa Maria, CA), Ellis Garai (Sherman Oaks, CA), Kristen Jaax (Santa Clarita, CA), Rafael Carbunaru (Valley Village, CA)
Application Number: 12/258,382
International Classification: A61F 2/02 (20060101); A61F 2/28 (20060101);
