System and method for securing an implant to tissue

A system and method for securing a medical implant within a patient. The method comprises disposing an anchor element around the implant, the anchor element including a pair of tabs each including an eyelet, and a flexible intermediate portion between the tabs, wherein disposing the anchor element around the implant includes positioning the implant within the intermediate portion and folding the anchor element such that the tabs contact one another and the eyelets aligned. The anchor element is positioned at a desired implantation position with the tabs positioned proximate soft tissue of the patient. The method further comprises inserting a distal tip of a fixation element delivery tool through the eyelets and into the soft tissue, the fixation element including at least one tissue anchor and an adjustable suture arrangement coupled to the tissue anchor. The at least one tissue anchor is deployed from the delivery tool and into the soft tissue of the patient. The delivery tool is withdrawn from the soft tissue and the eyelets of the anchor element, and the adjustable suture arrangement is tightened to secure the anchor element against the soft tissue.

TECHNICAL FIELD

The present invention relates to devices and methods for anchoring implants within a patient's body. More specifically, the invention relates to methods for anchoring elongated implants to tissue using an implantable suture assembly and associated delivery tools.

BACKGROUND

Conventional techniques for anchoring elongated implants, e.g., implantable catheters for use in pain management systems such as stimulators, drug pumps and deep brain stimulation (DBS) systems require manually tying one or more sutures to engage the elongated implant to the patient's soft tissues. There is a need for improved anchoring techniques for such devices.

SUMMARY

In one embodiment, the present invention is a system and method for securing a medical implant within a patient. The method comprises disposing an anchor element around the implant, the anchor element includes a pair of tabs, each including an eyelet, and a flexible intermediate portion between the tabs, wherein disposing the anchor element around the implant includes positioning the implant within the intermediate portion and folding the anchor element such that the tabs contact one another and the eyelets align. The anchor element is positioned at a desired implantation position with the tabs positioned proximate soft tissue of the patient. The method further comprises inserting a distal tip of a fixation element delivery tool through the eyelets and into the soft tissue, the fixation element including at least one tissue anchor and an adjustable suture arrangement coupled to the tissue anchor. The at least one tissue anchor is deployed from the delivery tool and into the soft tissue of the patient. The delivery tool is withdrawn from the soft tissue and the eyelets of the anchor element, and the adjustable suture arrangement is tightened to secure the anchor element against the soft tissue. While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

DETAILED DESCRIPTION

FIG. 1is a schematic illustration showing an elongated medical implant10secured to soft tissue15using an anchor element20and a fixation element25according to one embodiment of the present invention. As shown inFIG. 1, the implant10has a flexible, elongated body. In various embodiments, the implant10can be any conventional implantable device for use in, for example pain management systems such as stimulators, drug pumps and deep brain stimulation (DBS) systems. As is known in the art, such implant can be in the form of electrode leads or catheters coupled to an implanted therapy device (not shown) such as a stimulator or drug pump. The particular type of therapy device employed is not critical to the various embodiments of the present invention.

The implant10is secured in a desired implantation position by the anchor element20and the fixation element25. In the illustrated embodiment, the anchor element20is coupled to and frictionally engages the implant10, and the fixation element25is securely coupled to the anchor element20and the soft tissue15, thereby securing the implant10in place to inhibit movement of the anchor element20and the implant10at the fixation site. The particular fixation site, and in turn, the particular soft tissues to which the implant10, the anchor element20and the fixation element25will be secured, depends on the particular type of therapy being delivered. For example, stimulators for pain management can be used to directly stimulate the spinal cord or spinal nerves, and thus the implants10used therewith will be secured to tissue adjacent the patient's vertebral column. Similarly, pain pumps and the associated implants10may also be implanted near the vertebral column and secured to similar tissues, e.g., connective tissue or fascia. The anchor elements20and the fixation elements25discussed herein are adapted for use in connection with a variety of implantation locations and tissue types.

FIGS. 2 and 3are perspective views of the medical implant10and the anchor element20prior to implantation according to one embodiment. As shown, the implant10has a flexible, elongated body30made of a biocompatible material. In various embodiments, the implant10may include an internal lumen (not shown) for conveying a payload (e.g., drug) and/or to assist in delivery by receiving a stylet, guidewire or similar delivery instrument. In addition or in lieu of an internal lumen, depending on the type of implant10and therapy device being employed, the implant10may include internal conductor wires (also not shown) to couple the therapy device to other structures, e.g., electrodes (not shown), on the implant10. In various embodiments, the implant body30of the implant10may be made of a biocompatible elastomeric or polymeric material, e.g., silicone rubber, polyurethane and the like.

In the illustrated embodiment, the anchor element20includes a tab40having an eyelet45and a suture notch47, an opposite tab50having an eyelet55and a suture notch57, and an intermediate portion60between the tabs40,50. As shown, the anchor element20is configured so that the implant10can be received within the intermediate portion60of the anchor element10. Thus, the intermediate portion60is configured as a generally tubular sleeve sized to receive the implant10. In one embodiment, the intermediate portion60can be configured with a side-opening slit through which the implant10can be laterally inserted, after which the intermediate portion60partially or completely closes about the implant10. In another embodiment, the intermediate portion60can be a continuous tubular sleeve, such that the implant10can be longitudinally inserted into the sleeve to occupy the position shown inFIG. 2disposed about the body30of the implant10.

In the illustrated embodiment, anchor element20is a wing-type anchor, in that tabs40,50extend laterally like wings with respect to the intermediate portion60. In the various embodiments, the anchor element20is sufficiently flexible such that the tabs40,50can be folded toward one another until they are in abutment with one another. This configuration is shown inFIG. 3. As shown, in this folded configuration, the eyelets45,55are aligned with one another so that they can receive the fixation element25, as shown and explained in further detail below. As further shown, in the illustrated embodiment, a suture loop70is disposed about the tabs40,50within the notches47,57, which operates to retain the anchor element20in the folded configuration shown inFIG. 3. In various embodiments, folding the anchor element20as shown inFIG. 3tends to cause the intermediate portion60to radially compress the implant body30, thus increasing frictional engagement between the intermediate portion60and the implant body30. This engagement serves to enhance the anchoring function of the anchor element20.

In various other embodiments of the invention, however, the anchor element20is not folded over. Rather, the anchor element20can remain in its unfolded state as shown inFIG. 2and the anchor element and implant10can be secured to the soft tissue15using two fixation elements25each corresponding to one of the eyelets45,55, or alternatively, a single fixation element25including portions inserted through each of the eyelets45,55.

In various embodiments, the anchor element20can be made from any variety of relatively pliable biocompatible materials. In various embodiments, such materials can include silicone rubber, polyurethane, or similar polymers. In various embodiments, the intermediate portion60can include surface features or treatments (e.g., roughening, bumps, ridges, and the like) to enhance frictional engagement with the body30of the implant10.

FIG. 4is a schematic illustration of a fixation element25according to one embodiment. As shown, the fixation element25includes a pair of tissue anchors80,85and an adjustable suture arrangement90coupled to the tissue anchors80,85. In the illustrated embodiment, the suture arrangement90includes a primary suture element95forming an adjustable suture loop98including a knot100and a tether105allowing the suture loop to be tightened to reduce the size of the suture loop98.

As further shown, the suture arrangement90includes connecting sutures110,115coupling the tissue anchors80,85, respectively, to the primary suture element95within the suture loop98. In the illustrated embodiment, the connecting sutures110,115are formed as suture loops through which the primary suture element95extends and connected, respectively, to the tissue anchors80,85. This configuration of the connecting sutures110,115allows them to slide along the primary suture element95as the suture loop98is tightened. In the illustrated embodiment, the suture5arrangement98also includes a safety line120fixedly connected to the connecting suture115. In some embodiments, the safety line120is omitted.

In general, the suture arrangement90can be configured and used in substantially the same or an identical manner as any of the suture and anchor assemblies illustrated inFIGS. 7A-7C,8A-8C,9and33A-33D and described in the corresponding text of commonly-assigned U.S. Patent Application Publication 2007/0100348. In addition, the suture arrangement90can be delivered using a fixation element delivery tool such as, for example, the fixation delivery apparatus illustrated inFIGS. 33A-33Dof the aforementioned U.S. Patent Application Publication 2007/0100348 or the fixation delivery apparatus illustrated inFIGS. 76A-76Band described in the corresponding text of commonly-assigned U.S. Patent Application Publication 2010/0094425. Each of the foregoing U.S. patent application publications is incorporated herein by reference in its entirety. Thus, the suture arrangement90is configured such that the tissue anchors80,85can be slidably received in series in a tubular cannula of the delivery tool, with the tissue anchor80positioned within the tubular cannula distal to the tissue anchor85such that the tissue anchor80will be ejected first from the tubular cannula and into the soft tissue of the patient proximate the implantation site. As further described in the aforementioned U.S. patent application publications, the delivery tool can then be repositioned and the tubular cannula reinserted into the tissue at a different location with a portion of the suture loop98of the suture arrangement90spanning across and over the implantation site. When present, the safety line120is secured to the delivery tool and operates to prevent unintended ejection of the tissue anchor85during ejection of the tissue anchor80and repositioning of the delivery tool. Once both tissue anchors80,85are inserted into the tissue, the suture loop98can be tightened by pulling on the tether105under resistance applied by engagement of the tissue anchors80,85and the tissue. Excess lengths of the tether105and the safety line120can then be manually cut away or automatically cut by a feature in the delivery tool.

FIGS. 5A-5Bthrough7A-7B are perspective views and side views, respectively, of the medical implant10and anchor element20in progressive stages of implantation using the fixation element25and a fixation element delivery tool as 6 described above, according to one embodiment. As shown inFIGS. 5A-58, with the suture loop70holding the anchor element20in its folded configuration and the implant10positioned within the intermediate portion60of the anchor element, the anchor element20and implant10are positioned as desired against or proximate the tissue15at the implantation site. As further shown, a cannula190of a fixation element delivery tool195, which as explained previously, carries the fixation element25, is inserted through the eyelets45,55of the anchor element20and into the tissue15.FIGS. 5A-58also show the tissue anchor80of the fixation element25after it has been ejected from the cannula190into the tissue15so as to engage the tissue15.

As shown inFIGS. 6A-68, the cannula190is then withdrawn from the tissue15and the eyelets45,55, and then repositioned to the side of the anchor element20such that a portion of the adjustable suture arrangement90spans over and across the intermediate portion60of the anchor element. As further shown, the cannula190can then be re-inserted into the tissue15proximate the anchor element20.

Next, as can be seen inFIGS. 7A-78, after the tissue anchor85has been deployed into the tissue at the second insertion location, the cannula190can be withdrawn again and the tether105pulled to tighten the adjustable suture arrangement90with the engagement of the tissue anchors80,85and the tissue15resisting the pulling force. In this manner, the portion of the adjustable suture arrangement90spanning across the intermediate portion60of the anchor element20compresses the intermediate portion60against the tissue, thus securing the anchor element20and the implant10in place. As discussed previously, any excess length of the suture arrangement90can then be cut away.

FIG. 8is a schematic illustration of an alternative fixation element200for use in securing the medical implant10and the anchor element20ofFIG. 1to tissue according to another embodiment. As shown, the fixation element200includes a tissue anchor205, a suture arrangement210and a pledget215. The tissue anchor205is fixedly connected to one end of the suture arrangement210, and the pledget215is fixedly connected to an opposite end of the suture arrangement210, with a slip knot217disposed in the suture arrangement210between the tissue anchor205and the pledget215, and a tether218extends from the slip knot217in a proximal direction.7The suture arrangement210is configured such that pulling on the tether218causes the tissue anchor205to be drawn toward the pledget to place the suture arrangement210between the pledget215and the tissue anchor205in tension. In general, the suture arrangement200can be configured and used in substantially the same or an identical manner as the fixation elements illustrated inFIGS. 13-14and described in the corresponding text of commonly-assigned U.S. Patent Application Publication 2007/0100348, which is incorporated herein by reference in its entirety.

In various embodiments, the fixation element200can be delivered using a fixation element delivery tool such as, for example, the delivery device400illustrated inFIGS. 13-15and20-21and described in the corresponding text of commonly-assigned U.S. Patent Application Publication 2007/0100348, which is incorporated herein by reference in its entirety. As described in the aforementioned U.S. patent publication, the delivery tool for the fixation element200includes a tubular cannula configured to receive the tissue anchor205during insertion in to the tissue at the implantation site, and upon withdrawal of the tubular cannula from the tissue, to cause the suture arrangement210between the tissue anchor205and the pledget215to be placed in tension under resistance supplied by engagement of the tissue by the tissue anchor205.

FIGS. 9A-9Band10A-10B are perspective views and side views, respectively, of the medical implant10and anchor element20in stages of implantation using the fixation element200and a fixation element delivery tool250according to another embodiment. As shown inFIGS. 9A and 9B, with the suture loop70holding the anchor element20in its folded configuration and the implant10positioned within the intermediate portion60of the anchor element, the anchor element20and implant10are positioned as desired against or proximate the tissue15at the implantation site. As further shown, the fixation element delivery tool250, which as explained previously, carries the fixation element200, includes a cannula255that is inserted through the eyelets45,55of the anchor element20and into the tissue15.FIGS. 9A-9Balso show the tissue anchor205of the fixation element200after it has been ejected from the cannula255into the tissue15so as to engage the tissue15. As further shown, with the 8 cannula255inserted the desired distance into the tissue15, the pledget215of the fixation element200bears against the tab40of the anchor element20.

As can be seen inFIGS. 10A-10B, the cannula255is then withdrawn from the tissue15and from the eyelets45,55of the anchor element20, which in turns pulls on the tether218thus tending to pull together the tissue anchor205and the pledget215. Because, as shown inFIGS. 10A-10B, the pledget215bears against the tab40and the tissue anchor205is embedded in and in engagement with the tissue15, this pulling action tends to compress the tabs40,50of the anchor element against the tissue15thus securing the anchor element20and the implant10in place. Here again, any excess length of the suture arrangement of the fixation element200can then be cut away.

As discussed previously, the fixation elements25,200and the methods discussed herein can be used in connection with any implants and anchor elements of similar structure to the anchor element20, e.g., including eyelets or similar features for receiving sutures and tissue anchors such as those utilized in the fixation elements25,200.

In addition, in the illustrated embodiments, only a single fixation element25,200is illustrated and described. In various embodiments, however, additional fixation elements25,200can be used in combination. For example, in one embodiment, two fixation elements25can be utilized, one being deployed as described above, and another being deployed across the intermediate portion60or the tabs40,50to provide additional fixation to the tissue15. In another embodiment, a fixation element200can be deployed as described above, and a fixation element25can also be deployed with a tissue anchor80,85on either side of the intermediate portion60of the anchor element20. Additional combinations of fixation elements25,200will be readily apparent to those skilled in the art based on the foregoing.

FIG. 11Ais a schematic view of an alternative fixation element225, andFIG. 11Bis a schematic end view illustrating the fixation element225in use in an alternative technique for anchoring an implant, such as the implant10, to soft tissue15. As shown, the implant10with the anchor element20coupled thereto can be sutured to the soft tissue15using the alternative fixation element225, which in the illustrated 9 embodiment is in the form of a barbed suture. As shown, the barbed suture fixation element225includes a main body230having an eyelet232at its proximal end, and a plurality of barbs235projecting laterally from the main body230along the length thereof. As shown inFIG. 11A, a curved needle234is connected to the body230at its distal end, and this facilitates deploying the fixation element225in a conventional manner such as is typically used for suturing tissue. As further shown, the distal end of the body230can be routed through the eyelet232to form a suture loop extending around the anchor element20of the implant10. The barbs235are oriented so as to allow the body230to be routed through the eyelet232, but because they extend laterally relative to the body230, to prevent subsequent withdrawal of the body230through the eyelet232in the opposite direction. The cooperation of the eyelet232and the barbs235thus form a locking arrangement to secure the fixation element225under tension, thereby securing the implant10to the tissue15. This arrangement thus eliminates the need for a separate knot to facilitate tightening the suture. In addition, the orientation of the barbs235further provides minimal resistance to forward advancement of the fixation element225into the tissue15, while at the same time resisting movement of the fixation element225in the reverse direction.

In various embodiments, the barbed fixation element225can be manually deployed in a conventional manner, e.g., using a suture needle and a manual suturing technique as is known in the art. In various embodiments, the barbed fixation element225can be coupled to one or more tissue anchors and pre-loaded onto a fixation element delivery tool such as, for example, the fixation delivery apparatus illustrated inFIGS. 33A-33Dof the aforementioned U.S. Patent Application Publication 2007/0100348 or the fixation delivery apparatus illustrated inFIGS. 76A-76Band described in the corresponding text of commonly-assigned U.S. Patent Application Publication 2010/0094425.

The barbed fixation element225can be formed from a variety of biocompatible materials, including materials conventionally used in suture manufacture. Exemplary materials include, without limitation, polymers made of polyglycolic acid, poly-tri-methylene-carbonate, poly-1,4-dioxane-2-one, poly-caprolactone, p-dioxanone, nylon 6, and isotactic polypropylene. However, it is emphasized that the particular10materials used for manufacturing the barbed fixation element225is not limited to any particular material.