SPIRAL DELIVERY SYSTEM FOR EMBOLIC BRAID

Abstract

A device for treating an aneurysm with a braided implant can include a delivery tube having a spiral groove on an outer surface of the delivery tube and a braided implant having a spiral segment. The spiral segment can engage the spiral groove as the braided implant is delivered to an aneurysm treatment site. At the treatment site, the braided implant can be implanted, and the delivery tube can be rotated to disengage the spiral segment from the spiral groove. Once released, the spiral segment can reshape to occlude the neck of the aneurysm.

Claims

1. A system comprising: a delivery tube configured to travel through vasculature and comprising a lumen therethrough, a distal end, an outer surface, and a helical structure on the outer surface; a braided tubular implant movable from a delivery configuration to an implanted configuration, the delivery configuration comprising a tubular segment extending proximally within the lumen of the tubular delivery member and an outer fold segment covering a portion of the outer surface of the tubular delivery member, and the implanted configuration comprising an occlusive sack comprising an opening; and a coiled element movable from an engaging configuration to an occluding configuration upon rotation of the tubular delivery member in relation to the braided tubular implant, wherein at least a portion of the coiled element is shaped in a circular helix shape and engages the helical structure when the coiled element is in the engaging configuration, and wherein the portion of the coiled element shaped in the circular helix shape obstructs at least a portion of the opening of the occlusive sack when the coiled element is in the occluding configuration by forming a conical helix or a planar spiral.

2. The system of claim 1, wherein the helical structure is an indentation in the shape of a circular helix.

3. The system of claim 1, wherein the coiled element comprises a memory shape metal, and wherein the memory shape metal is configured to move from a deformed shape when the coiled element is engaged with the helical structure to a predetermined shape upon disengaging from the helical structure.

4. The system of claim 1, wherein the coiled element comprises an affixed portion affixed to the braided implant, and wherein the coiled element further comprises: an affixed end affixed to the affixed portion of the coiled element; a terminating end; a first circumference measured along the coiled element from the affixed end through one turn of the conical helix in the direction of the terminating end; and a second circumference measured along the coiled element from the terminating end through one turn of the conical helix in the direction of the affixed end, the second circumference measuring shorter than the first circumference.

5. The system of claim 4, wherein the affixed portion is circular and has a circumference sized to fit over the outer surface of the delivery tube, and the coiled segment has a helical shape sized to engage the helical structure on the outside of the delivery tube.

6. The system of claim 4, wherein the braided tubular implant inverts to form the occlusive sack and the coiled segment moves to obstruct the opening in the occlusive sack, and wherein the occlusive sack and the affixed portion of the coiled element are joined at the opening of the occlusive sack.

7. The system of claim 6, wherein the affixed portion of the coiled element defines the opening of the occlusive sack and the coiled segment obstructs the opening of the occlusive sack.

8. An implantation system comprising: a delivery tube comprising a lumen therethrough, a distal end, an outer surface, and a helical groove on the outer surface thereon; and an implant comprising: a tubular braid movable to an implanted shape comprising an occlusive sack comprising an opening, and a coiled element extending from the opening of the tubular braid, wherein a portion of the coiled element shaped in a circular helix shape is positioned within the helical groove, wherein the coiled element is configured, upon rotation of the delivery tube in relation to the tubular braid, to disengage from the helical groove and thereby disengage the implant from the delivery tube, and wherein the portion of the coiled element shaped in the circular helix shape is configured to obstruct at least a portion of the opening of the occlusive sack of the tubular braid by forming a conical helix or a planar spiral upon disengaging from the helical groove.

9. The implantation system of claim 8, wherein the helical structure is an indentation in the shape of a circular helix.

10. The implantation system of claim 8, wherein the coiled element comprises a memory shape metal, and wherein the memory shape metal is configured to move from a deformed shape when the coiled element is engaged with the helical groove to a predetermined shape upon disengaging from the helical structure.

11. The implantation system of claim 8, wherein the coiled element comprises an affixed portion affixed to the braided implant, and wherein the coiled element further comprises: an affixed end affixed to the affixed portion of the coiled element; a terminating end; a first circumference measured along the coiled element from the affixed end through one turn of the conical helix in the direction of the terminating end; and a second circumference measured along the coiled element from the terminating end through one turn of the conical helix in the direction of the affixed end, the second circumference measuring shorter than the first circumference.

12. The implantation system of claim 11, wherein the affixed portion is circular and has a circumference sized to fit over the outer surface of the delivery tube, and the coiled segment has a helical shape sized to engage the helical groove on the outside of the delivery tube.

13. The implantation system of claim 11, wherein the braided tubular implant inverts to form the occlusive sack and the coiled segment moves to obstruct the opening in the occlusive sack, and wherein the occlusive sack and the affixed portion of the coiled element are joined at the opening of the occlusive sack.

14. The implantation system of claim 13, wherein the affixed portion of the coiled element defines the opening of the occlusive sack, and the coiled segment obstructs the opening of the occlusive sack.

15. A method comprising: collapsing a coiled element affixed to a braided implant within a helical groove on a delivery tube so that the coiled element is positioned over an outer surface of the delivery tube and releasable from the delivery tube upon rotation of the delivery tube in relation to the braided implant; inserting a majority of the braided implant within a lumen of the delivery tube; configuring the delivery tube and braided implant for delivery through vasculature; moving the braided implant to an implanted shape comprising an opening from which the affixed portion and coiled element extend; and disengaging the coiled element from the helical groove, thereby causing the coiled element to form a conical helix shape or planar spiral shape within the opening of the implanted shape and to obstruct the opening of the implanted shape.

16. The method of claim 15, further comprising: shaping the coiled element such that the coiled element forms a conical helix shape or planar spiral shape upon disengaging from the helical groove.

17. The method of claim 15, further comprising: forming the coiled element to comprise a memory shape metal configured to move from a deformed shape when the coiled element is positioned within the helical groove to a predetermined shape upon the coiled element disengaging from the helical groove.

18. The method of claim 15, further comprising: pushing the majority of the braided implant distally from the lumen of the delivery tube.

19. The method of claim 18, further comprising: inverting a tubular portion of the braided implant as the tubular portion is pushed distally from the lumen of the delivery tube.

20. A method for treating an aneurysm, the method comprising: providing a braided implant delivery system comprising a braided implant comprising a coiled element affixed to the braided implant and a delivery tube comprising a spiral groove; engaging the coiled element with the spiral groove; implanting the braided implant in the aneurysm; rotating the delivery tube in relation to the coiled element of the braided implant to disengage the coiled element from the spiral groove; releasing the coiled element from the delivery tube which releases the braided implant from the delivery tube; moving a portion of the coiled element from a circular helix shape to a conical helix shape or planar spiral shape; and occluding at least portion of the neck of the aneurysm with the coiled element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and further aspects of this invention are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.

[0027] FIG. 1a illustrates an exploded view of a braided implant and a delivery tube according to the present invention;

[0028] FIG. 1b illustrates a braided implant engaged with a delivery tube according to the present invention;

[0029] FIG. 1c illustrates a cross-sectional view of the braided implant and the delivery tube of FIG. 1b according to the present invention;

[0030] FIG. 2 illustrates a cut-sectional view delivery system according to the present invention;

[0031] FIG. 3 illustrates a cut-away of an aneurysm during treatment according to the present invention;

[0032] FIGS. 4a to 4e illustrate a method of use of a device of the present invention;

[0033] FIG. 5 illustrates a cut-away of an aneurysm implanted with a braided implant according to the present invention;

[0034] FIG. 6 illustrates a view of a braided implant as viewed at the neck of an aneurysm treated according to the present invention;

[0035] FIGS. 7a to 7b illustrate a braided implant and a coiled element according to the present invention;

[0036] FIG. 8a illustrates a braided implant and a coiled element according to the present invention;

[0037] FIG. 8b illustrates a view of the braided implant and coiled element of FIG. 8a as viewed at the neck of an aneurysm treated according to the present invention; and

[0038] FIGS. 9 to 11 are flow diagrams outlining example method steps for use of a device according to the present invention.

DETAILED DESCRIPTION

[0039] Previous approaches utilizing embolic coils can be improved upon by treating the aneurysm entrance and/or packing the aneurysm with an embolic braided implant. For example, see U.S. Pat. Application No. 15/903,860, incorporated herein, in its entirety, by reference. Treating the aneurysm with the braided implant can have potential advantages over treatments utilizing embolic coils such as a higher packing density, ability to retract and reposition the implant during the implantation procedure, ability to be implanted without ancillary devices such as stents or balloons, reduced risk of recanalizing or compacting, and improved coverage across the aneurysm neck, for example.

[0040] In braided implant delivery systems, it can be advantageous to maintain an attachment between the implant and the delivery system until the implant is in place at the treatment site, then detach the implant so that the delivery system can be extracted. When implanted in an aneurysm, for example, the delivery system can also serve to occlude the neck of the aneurysm. The present disclosure describes various example systems, devices, and methods that can be utilized for at least such purposes.

[0041] FIG. 1a illustrates an exploded view of a braided implant 300 and a delivery tube 500. The braided implant 300 is shown in a delivery configuration, shaped to be delivered to a treatment site by the delivery tube 500. FIG. 1b illustrates the braided implant 300 engaged with the delivery tube 500. The assembly illustrated in FIG. 1b is sized to be inserted into and travel through a microcatheter 600 to a treatment site. The microcatheter 600 is shown cut-away in FIG. 1b, and the delivery system is shown approaching a distal end 614 of the microcatheter 600. FIG. 1c illustrates a cross-section of the braided implant 300, delivery tube 500, and microcatheter as indicated in FIG. 1b.

[0042] Referring to FIGS. 1a to 1c collectively, the braided implant 300 can have an inner fold segment 304 shaped to be positioned within a lumen 504 of the delivery tube 500, a fold 303 that can be positioned distal a distal end 514 of the delivery tube 500, an outer fold segment 302 that can extend proximally from the fold 303 to cover a portion of an outer surface 508 of the delivery tube 500, and a spiral segment 350 that can engage a spiral groove 550 on the delivery tube 500.

[0043] The spiral segment 350 can be elongated with a helical, coiled, or spiral shape. The spiral segment 350 can have an attached end 354 attached to the outer fold segment 302 and can extend proximally to a terminating end 352. The spiral segment 350 can include a woven material with a weave that is common to the braided implant 300 such that the weave of the outer fold segment 302 and the weave of the spiral segment 350 share a common fiber. Alternatively, the spiral segment 350 can include a non-woven material and can be attached to the braided implant 300 by some other means.

[0044] The spiral segment 350 and the spiral groove 550 can be compatibly dimensioned so that the spiral segment 350 stays in place within the groove as the system is delivered through a catheter 600 to a treatment site. The groove can be deep enough for the spiral segment 350 to fit in without falling out. The width of the groove can be dimensioned to a fit such that the spiral segment 350 has minimal room to move within the groove.

[0045] FIG. 2 shows a cross-section of a delivery system including a delivery tube 500, a braided implant 300, and an inner elongated member 400. The length of the delivery system has been truncated for the purposes of the illustration.

[0046] The delivery system can be sized to be delivered to a treatment site through a catheter or microcatheter 600. The proximal end 412 of the inner elongated member 400 can extend from the proximal end 512 of the delivery tube 500, which can in turn extend from the proximal end 612 of the delivery catheter 600. The proximal end of the delivery system can be made available to a user to facilitate positioning and implantation of the braided implant 300 at a treatment site.

[0047] The braided implant 300 can include an inner fold segment 304, extending proximally during delivery and attaching at a first end 312 to the inner elongated member 400. A first end 312 of the braided implant 300 can be detachably attached to the inner elongated member 400 at a distal end 414 by a braid release 404. The inner elongated member 400 can be positioned within the lumen 504 of the delivery tube 500 having a proximal end 412 extending proximal from a proximal end 512 of the delivery tube 500. The braided implant 300 can have a second end 314.

[0048] During delivery, the inner fold segment 304 can be enveloped by the delivery tube 500 and held at the first end 312 by the inner elongated member 400. Once the delivery system is positioned at a treatment site, the inner elongated member 400 can be pushed distally, causing the inner fold segment 304 of the braided implant 300 to exit the distal end 514 of the delivery tube 500. The first end 312 of the braided implant 300 can be detached from the inner elongated member 400 at the braid release 404.

[0049] As shown in FIG. 2, the braided implant 300 can have a fold 303 distal the distal end 514 of the delivery tube 500 and an outer fold segment 302 extending proximally over an outer surface 508 of the delivery tube 500 to a second end 314 of the braided implant 300. The second end 314 of the braided implant 300 can be attached to a spiral segment 350 that can engage a spiral groove 550 in the outer surface 508 of the delivery tube 500.

[0050] FIG. 3 illustrates a cut-away of an aneurysm 10 during treatment of a delivery system including a braided implant 300. The braided implant 300 can be delivered through a blood vessel 20 to an opening 16 in the blood vessel wall 22 by a microcatheter 600. As shown, the braided implant 300 can invert to form an occlusive sack 308 that can extend to contact the aneurysm wall 14 and fill the aneurysm sac 12. Portions of the braided implant 300 not inverted can be pushed into the occlusive sack 308 by the inner elongated member 400 (shown in FIG. 2), forming an embolic filler braid 310. FIG. 3 shows the braided implant 300 partially implanted, such that a portion of the inner fold segment 304 remains in the delivery catheter 600.

[0051] FIGS. 4a to 4e illustrate a method of treating an aneurysm 10 with a braided implant delivery system. FIG. 4a shows the system positioned within a blood vessel 20 at the aneurysm neck 16. FIG. 4a shows the braided implant 300 in a delivery configuration and the spiral segment 350 in an engaging configuration engaging the spiral groove 550 of delivery tube 500.

[0052] FIG. 4b shows an occlusive sack 308 and an embolic filler braid 310 that can be formed by inverting a portion of an inner fold segment 304 of the braided implant 300 and ejecting a non-inverted portion of the inner fold segment 304 respectively.

[0053] FIG. 4c shows the spiral segment 350 moving distally in response to a rotation of the delivery tube 500. The spiral segment 350 can be sized to easily glide within the spiral groove 550 as the delivery tube 500 is rotated. The occlusive sack 308 can contact the aneurysm wall 14, providing a resistance to prevent the implant 300 from rotating in response to the rotation of the delivery tube 500. As shown, the spiral segment 350 can exit the distal end 614 of the microcatheter 600 as it moves distally in response to the rotation. Alternatively (not shown), the microcatheter 600 can be retracted before rotation of the delivery tube 500.

[0054] FIG. 4d shows the spiral segment 350 continuing to move distally in response to continued rotation of the delivery tube 500. As portions of the spiral segment 350 disengage the spiral groove 550, the spiral segment 350 can begin to flatten or reshape.

[0055] FIG. 4e shows the spiral segment 350 disengaged with the delivery tube 500 and reshaped to an occluding configuration. As shown, the spiral segment 350 can move from a circular helix shape in the engaged configuration to a conical helix shape in the occluding configuration. Alternatively, the spiral segment 350 can be otherwise shaped in either the engaging or occluding configuration as will be understood by a person of ordinary skill in the art; for example, the spiral segment 350 can occlude an aneurysm neck with a shape such as a planar spiral.

[0056] Movement of the spiral segment 350 from the engaged configuration to the occluding configuration can be accomplished by various means. For example, the spiral segment 350 can be made with a memory shape metal having a predetermined shape and a deformed shape. In such an example, the spiral segment 350 can have a deformed shape in the engaging configuration; a rotation of the delivery tube 500 can cause the spiral segment 350 to contact bodily fluid as the spiral segment 350 exits the microcatheter 600; and the spiral segment 350 can move to the predetermined shape in response to contacting the bodily fluids, the spiral segment 350 having the predetermined shape in the occluding configuration.

[0057] Alternatively, the spiral segment 350 can be made with an elastically deformable material. In such an example, the spiral segment 350 can have a stretched shape in the engaging configuration and can be sized to fit within a spiral groove 550 on an outer surface 508 of the delivery tube 500; a rotation of the delivery tube 500 can cause the spiral segment 350 to glide off of the distal end 514 of the delivery tube 500; and the spiral segment 350, now uninhibited by the delivery tube 500, can return to its original shape, the spiral segment 350 having the original shape in the occluding configuration.

[0058] FIG. 5 shows a cut-away view of an aneurysm 10 implanted with a braided implant 300. The braided implant 300 can form an occlusive sack 308 that can extend to the aneurysm wall 14, and the occlusive sack 308 can be filled with an embolic braid 310. The occlusive sack 308 and the embolic braid 310 can pack the aneurysm 10 to create a thrombotic mass, thereby providing one method of treatment to the aneurysm 10. As shown, the occlusive sack 308 can at least partially occlude the neck 16 of the aneurysm 10 reducing blood flow across the entrance to the aneurysm 10 and thereby providing a second method of treatment to the aneurysm 10. However, the occlusive sack 308 can have an opening 309 positioned in the aneurysm neck 16. Blood flow across the entrance of the aneurysm 10 can be further inhibited by obstructing the opening 309. As shown in FIG. 5, the spiral segment 350 can obstruct at least a portion of the opening 309, thereby occluding at least a portion of the neck 16 of the aneurysm 10.

[0059] FIG. 6 depicts braided implant 300 having a spiral segment 350 implanted into an aneurysm 10 as viewed from within a blood vessel 20. From this perspective, the blood vessel wall 22 surrounds the aneurysm neck 16, and the occlusive sack 308 is shown occluding the aneurysm neck 16 around the perimeter of the aneurysm neck 16. The occlusive sack 308 is shown having an opening 309 with a perimeter 319 that is measured from the attached end 354 of the spiral segment 350, around the perimeter 319 of the opening 309 one turn. The spiral segment 350 is shown spiraling counterclockwise inward from the attached end 354 to a terminating end 352. As shown, the spiral segment 350 can have an outer circumference 358 measured starting from the attached end 354 counterclockwise in the direction of the terminating end 352 through one turn, and an inner circumference 356 measured starting from the terminating end 352 clockwise in the direction of the attached end 354 through one turn. Because the spiral segment 350 spirals inward from the attached end 354, the outer circumference 358 measures greater than the inner circumference 356. As shown, the terminating end 352 can be positioned near a center 329 of the occlusive sack opening 309.

[0060] FIGS. 7a to 7b illustrate a braided implant 300 and a coiled element 200. As shown, the coiled element 200 can include an affixed portion 210 that is affixed to an end 314 of the outer fold segment 302 of the braided implant 300 and a coiled segment 220 extending from the affixed end 224 of the affixed portion 210 to a terminating end 222 over inner fold segment 304. The affixed portion 210 can be circular, having a circumference sized to fit over an outer surface of a delivery tube (not shown), and the coiled segment 220 can have a helical shape sized to engage a helical structure on the outside of a delivery tube (not shown). FIGS. 7a and 7b show the braided implant 300 in a delivery configuration and the coiled element 200 in an engaged configuration, each configured to be delivered by a delivery tube 500 through a catheter 600 to a treatment site.

[0061] FIG. 8a shows a braided implant 300 in a deployed configuration and a coiled element 200 in an occluding configuration. The braided implant 300 can invert to form an occlusive sack 308, and the coiled segment 220 can move to obstruct an opening 309 in the occlusive sack 308. The occlusive sack 308 and the affixed portion 210 of the coiled element 200 can be joined at the opening 309 of the occlusive sack 308, and the affixed end 224 can be positioned at the perimeter of the opening 309. The braided implant 300 can collapse to form a conical helix, a flattened spiral, or some other shape to obstruct the opening 309 of the occlusive sack 308.

[0062] FIG. 8b depicts a braided implant 300 and a coiled element 200 implanted into an aneurysm 10 as viewed from within a blood vessel 20. From this perspective, the blood vessel wall 22 surrounds the aneurysm neck 16. The implant 300, as shown, can include an occlusive sack 308, and the coiled element can be in an occluding configuration, for example as shown in FIG. 8a. The occlusive sack 308 can occlude a portion of the aneurysm neck 16. FIG. 8b shows the occlusive sack 308 occluding a portion of the aneurysm neck 16 around a perimeter of the aneurysm neck 16. The affixed portion 210 of the coiled element 200 can define an opening 309 of the occlusive sack 308 that is not occluded by the occlusive sack 308. The coiled element can have a coiled structure that obstructs the opening 309 of the occlusive sack 308 thereby occluding a portion of the neck 16 of the aneurysm 10.

[0063] The coiled segment 220 can rotate clockwise (as shown) or counterclockwise. The coiled segment 220 can have an outer circumference 228 measured starting at the affixed end 224 affixed to the affixed portion 210 of the coiled element in the direction of the terminating end 222 through one turn and an inner circumference 226 measured starting at the terminating end 222 through one turn in the direction of the affixed end 224. The terminating end 222 can be positioned near the center 329 of the opening 309 of the occlusive sack 308, and the affixed end 224 can be positioned at the perimeter of the opening 309. So oriented, the outer circumference 228 can measure greater than the inner circumference 226.

[0064] FIGS. 9 to 11 are flow diagrams outlining example method steps for use of a device or system for treating an aneurysm 10. The method steps can be implemented by any of the example means described herein or by any means that would be known to one of ordinary skill in the art.

[0065] Referring to method 700 outlined in FIG. 9, in step 710 a braided implant delivery system having a delivery tube and a braided implant can be provided. The braided implant can have a spiral segment and the delivery tube can have a spiral groove. The braided implant delivery system can be any of the delivery systems described herein having any combination of the features described herein, as well as any features that would be known to one skilled in the art. In step 720 the spiral segment of the braided implant can be engaged with the spiral groove of the delivery tube. In step 730 the braided implant can be implanted in the aneurysm. In step 740 the delivery tube can be rotated in relation to the spiral segment to disengage the spiral segment from the spiral groove. In step 750 the spiral segment can be released from the delivery tube thereby releasing the braided implant from the delivery tube.

[0066] Referring to method 800 outlined in FIG. 10, in step 810 a braided implant delivery system having a braided implant and a delivery tube can be provided. The braided implant can have a spiral segment and the delivery tube can have a spiral groove. The braided implant delivery system can be any of the delivery systems described herein having any combination of the features described herein, as well as any features that would be known to one skilled in the art. In step 820 the spiral segment of the braided implant can be engaged with the spiral groove of the delivery tube. In step 830 the braided implant can be implanted in the aneurysm by forming an occlusive sack having an opening within the aneurysm. In step 835 the occlusive sack can contact a wall of the aneurysm. In step 840 the delivery tube can be rotated in relation to the spiral segment to disengage the spiral segment from the spiral groove. In step 845 a contact between the aneurysm wall and the occlusive sack can resist a rotation of the occlusive sack in response to the rotation of the delivery tube. In step 850 the spiral segment can be released from the delivery tube thereby releasing the braided implant from the delivery tube. In step 860 a portion of the spiral segment can be moved from a circular helix shape to a conical helix or flat spiral shape. In step 870 at least a portion of the neck of the aneurysm can be occluded by obstructing at least a portion of the opening of the occlusive sack with the spiral segment.

[0067] Referring to method 900 outlined in FIG. 11, in step 910 a braided implant delivery system having a braided implant, a delivery tube, and an inner elongated member can be provided. The braided implant can have a spiral segment and the delivery tube can have a spiral groove and a lumen. The braided implant delivery system can be any of the delivery systems described herein having any combination of the features described herein, as well as any features that would be known to one skilled in the art. In step 920 the spiral segment of the braided implant can be engaged with the spiral groove of the delivery tube. In step 923 the inner elongated member can be positioned in the lumen of the delivery tube. In step 927 the braided implant can be attached to the inner elongated member. In step 930 the braided implant can be implanted in the aneurysm by pushing the inner elongated member distally, thereby inverting the braided implant and forming an occlusive sack within the aneurysm then detaching the braided implant from the inner elongated member. In step 940 the delivery tube can be rotated in relation to the spiral segment of the braided implant to disengage the spiral segment from the spiral groove. In step 950 the spiral segment can be released from the delivery tube thereby releasing the braided implant from the delivery tube.

[0068] The descriptions contained herein are examples of embodiments of the invention and are not intended to limit the scope of the invention. As described herein, the invention contemplates many variations and modifications of a system, device, or method that can be used to treat an aneurysm with a braided implant. Variations can include but are not limited to alternative geometries of elements and components described herein, utilizing any of numerous materials for each component or element (e.g. radiopaque materials, memory shape metals, etc.), utilizing additional components including components to position the braided implant at a treatment site, extract the braided implant, or eject a portion of the braided implant from the interior of the delivery tube, utilizing additional components to perform functions described herein, or utilizing additional components to perform functions not described herein, for example. These modifications would be apparent to those having ordinary skill in the art to which this invention relates and are intended to be within the scope of the claims which follow.