Systems and methods for treating aneurysms
Treatment of aneurysms can be improved by delivering an occlusive member (e.g., an expandable braid) to an aneurysm sac in conjunction with an embolic element (e.g., coils, embolic material). A treatment system for such treatment can include an electrolytically corrodible conduit having a proximal portion, a distal portion, and a detachment zone between the proximal portion and the distal portion. An occlusive member having a proximal hub is coupled to the conduit distal portion. The conduit has a lumen configured to pass an embolic element therethrough. An inner electrode assembly can be slidably disposed within the conduit lumen to facilitate electrolytic detachment of the occlusive member at the detachment zone.
1 . A treatment system comprising:
a conduit comprising a proximal portion, a distal portion, and a sidewall, wherein the sidewall defines an electrolytically corrodible detachment zone between the proximal portion and the distal portion, wherein the detachment zone defines one or more apertures formed therein and/or defines a reduced wall thickness relative to non-detachment zone portions of the sidewall so that the detachment zone is configured to cause separation of the proximal portion and the distal portion in response to a flow of an electrical current through the detachment zone, and wherein the conduit defines a lumen configured to pass a liquid embolic element therethrough;
an expandable occlusive member comprising a proximal hub coupled to the conduit distal portion, wherein the occlusive member is configured to be positioned at an intrasaccular treatment site; and
an elongate conductive member slidably disposed within the lumen and slidable relative to the expandable occlusive member, the elongate conductive member comprising:
a distally located electrode configured to be disposed adjacent to the detachment zone; and
a plug element disposed proximal to the electrode,
wherein the elongate conductive member is axially movable relative to the conduit between a first position and a second position, wherein in the first position, the plug element is disposed distal to the detachment zone such that the lumen is configured to pass the liquid embolic element therethrough, and wherein in the second position, the plug element is disposed proximal to the detachment zone such that the plug element substantially occludes the lumen to prevent the liquid embolic element from passing distally beyond the plug element.
2 . The treatment system of claim 1 , wherein the conduit and conductive member are configured such that, in the presence of an electrolytic medium between the conduit sidewall and the conductive member, coupling the conduit to a first terminal of a power supply and coupling the elongate conductive member to a second terminal of a power supply causes current to flow between the detachment zone and the electrode.
3 . The treatment system of claim 1 , further comprising an elongate tubular liner having a second lumen configured to pass the liquid embolic element therethrough.
4 . The treatment system of claim 3 , wherein the liner is electrically insulative such that electrical current passing through the conduit does not pass through the liner, the liner defining a gap between a liner proximal portion and a liner distal portion that is configured to permit electrical current to flow therethrough.
5 . The treatment system of claim 1 , further comprising a sheath extending over the conduit, wherein the sheath is electrically insulative such that electrical current passing through the conduit does not pass through the sheath, wherein the sheath defines a gap between a sheath proximal portion and a sheath distal portion that is configured to permit electrical current to flow therethrough.
6 . The treatment system of claim 1 , wherein the elongate conductive member comprises a shaft portion having a first cross-sectional dimension, and the electrode comprises a portion of the elongate conductive member having a second cross-sectional dimension greater than the first cross-sectional dimension.
7 . The treatment system of claim 1 , wherein the elongate conductive member comprises a wire and the electrode comprises a ball disposed at a distal end portion of the wire.
8 . The treatment system of claim 1 , wherein the plug element defines a cross-sectional dimension that is substantially the same size as an inner cross-sectional dimension of the lumen.
9 . A treatment system comprising:
an elongate tubular member comprising:
a proximal portion, a distal portion, and a sidewall, wherein the sidewall defines an electrolytically corrodible detachment zone between the proximal portion and the distal portion, wherein the detachment zone defines one or more apertures formed therein and/or defines a reduced wall thickness relative to non-detachment zone portions of the sidewall; and
a lumen extending therethrough;
a medical device coupled to the tubular member distal portion; and
an elongate rod slidably disposed within the tubular member lumen and slidable relative to the medical device, the elongate rod having a distally located electrode configured to be disposed adjacent to the detachment zone and a plug element disposed proximal to the electrode, the plug element having a cross-sectional dimension that is substantially the same size as an inner cross-sectional dimension of the lumen,
wherein the elongate rod is axially moveable relative to the medical device between a first position and a second position, wherein in the first position, the plug element is disposed distal to the detachment zone such that the lumen is configured to pass a liquid embolic element therethrough, and wherein in the second position, the plug element is disposed proximal to the detachment zone such that the plug element substantially occludes the lumen to prevent the liquid embolic element from passing distally beyond the plug element.
10 . The treatment system of claim 9 , wherein the tubular member and rod are configured such that when, while in the presence of an electrolytic medium, the tubular member is coupled to a first terminal of a power supply and the elongate rod is coupled to a second terminal of a power supply, current flows between the detachment zone and the electrode.
11 . The treatment system of claim 9 , further comprising an electrically insulative liner extending through the tubular member lumen, the liner defining a gap between a liner proximal portion and a liner distal portion.
12 . The treatment system of claim 9 , further comprising an electrically insulative sheath extending over the tubular member, the sheath defining a gap between a sheath proximal portion and a sheath distal portion.
13 . The treatment system of claim 9 , wherein the electrode comprises a portion of the elongate rod that has an enlarged cross-sectional dimension.
14 . The treatment system of claim 9 , wherein the elongate rod comprises a wire and the electrode comprises a ball disposed at a distal end portion of the wire.
15 . The treatment system of claim 9 , wherein the plug element has an outer cross-sectional dimension that tapers in a proximal direction.
16 . A method comprising:
disposing an occlusive member at a treatment site, the occlusive member coupled to a distal end of a conduit having a sidewall that defines a detachment zone that includes one or more apertures formed therein and/or a reduced wall thickness relative to non-detachment zone portions of the sidewall;
expanding the occlusive member at the treatment site;
disposing an elongate conductive member within a lumen of the conduit in a first position such that a distally located electrode and a plug element disposed proximal to the electrode are positioned distal to the detachment zone;
delivering a liquid embolic element through the lumen of the conduit to the treatment site while the elongate conductive member is in the first position;
moving the elongate conductive member proximally relative to the conduit to a second position such that the electrode is positioned adjacent to the detachment zone and the plug element is substantially occludes the lumen;
applying a voltage across the conduit and the elongate conductive member while the elongate conductive member is in the second position, thereby electrolytically severing the conduit at the detachment zone; and
proximally retracting both the conduit and the conductive member while the occlusive member remains at the treatment site.
17 . The method of claim 16 , wherein the treatment site comprises an aneurysm sac.
18 . The method of claim 16 , wherein the elongate conductive member comprises a wire and the electrode comprises a ball disposed at a distal end portion of the wire.
19 . The method of claim 16 , wherein the plug element defines a cross-sectional dimension that is substantially the same size as an inner cross-sectional dimension of the lumen.