The field of the disclosed inventions generally relates to delivery devices for implanting vaso-occlusive devices for establishing an embolus or vascular occlusion in a vessel of a human or veterinary patient.
Vaso-occlusive devices or implants are used for a wide variety of reasons, including treatment of intra-vascular aneurysms. Commonly used vaso-occlusive devices include soft, helically wound coils formed by winding a platinum (or platinum alloy) wire strand about a “primary” mandrel. The coil is then wrapped around a larger, “secondary” mandrel, and heat treated to impart a secondary shape. For example, U.S. Pat. No. 4,994,069, issued to Ritchart et al., describes a vaso-occlusive coil that assumes a linear, helical primary shape when stretched for placement through the lumen of a delivery catheter, and a folded, convoluted secondary shape when released from the delivery catheter and deposited in the vasculature.
In order to deliver the vaso-occlusive coils to a desired site in the vasculature, e.g., within an aneurismal sac, it is well-known to first position a small profile, delivery catheter or “micro-catheter” at the site using a steerable guidewire. Typically, the distal end of the micro-catheter is provided, either by the attending physician or by the manufacturer, with a selected pre-shaped bend, e.g., 45°, 90°, “J”, “S”, or other bending shape, depending on the particular anatomy of the patient, so that it will stay in a desired position for releasing one or more vaso-occlusive coil(s) into the aneurysm once the guidewire is withdrawn. A delivery or “pusher” wire is then passed through the micro-catheter, until a vaso-occlusive coil coupled to a distal end of the delivery wire is extended out of the distal end opening of the micro-catheter and into the aneurysm. The vaso-occlusive device is then released or “detached” from the end delivery wire, and the delivery wire is withdrawn back through the catheter. Depending on the particular needs of the patient, one or more additional occlusive devices may be pushed through the catheter and released at the same site.
One well-known way to release a vaso-occlusive coil from the end of the delivery wire is through the use of an electrolytically severable junction, which is a small exposed section or detachment zone located along a distal end portion of the delivery wire. The detachment zone is typically made of stainless steel and is located just proximal of the vaso-occlusive device. An electrolytically severable junction is susceptible to electrolysis and disintegrates when the delivery wire is electrically charged in the presence of an ionic solution, such as blood or other bodily fluids. Thus, once the detachment zone exits out of the catheter distal end and is exposed in the vessel blood pool of the patient, a current applied through an electrical contact to the conductive delivery wire completes a circuit with a return electrode, and the detachment zone disintegrates due to electrolysis.
In a “monopolar” system, a return electrode (i.e., cathode) is attached to the patient's skin and/or a conductive needle is inserted through the skin at a remote site. In a “bipolar” system, the return electrode is located on the delivery wire, electrically insulated from the conductive path ending at the detachment zone (i.e., anode). The anode is typically made of an insulated core wire that runs through the delivery wire and is attached to the electrical contact at the proximal end. An exposed portion of the core wire forms the detachment zone at the distal end. The anode electrical contact may be a metallic tube secured to the proximal end of the delivery wire. Whether monopolar or bipolar, the distal end of the delivery wire can have a myriad of features, including a coil forming the delivery wire conduit, a reflowed polymer (e.g., polyether block amide or Pebax®) section covering the conduit, and an adhesive filled stopper coil plug inserted into the distal end of the conduit. These features result in the formation a relatively long stiff zone at the distal end of the delivery wire with sub-zones of extra stiffness when the features overlap. Perceived problems with current vaso-occlusive coil delivery systems include the long stiff zone at the distal end of the delivery wire, which reduces flexibility as the delivery wire is pushed through the micro-catheter. Reduced flexibility, combined with the orthogonal and axial forces exerted on the delivery wire as it is pushed through the micro-catheter, results in reduced durability.
Embodiments of the disclosed inventions are directed to delivery wire assemblies for delivery of occlusive devices to a location in a patient's vasculature.
In one embodiment, the delivery wire assembly has a distal end portion comprising a proximal rigid segment, a distal rigid segment, and a flexible segment disposed between the proximal and distal rigid segments. The delivery wire assembly may further include a delivery wire conduit having a proximal tubular portion coupled to a distal coil portion, the respective tubular and coil portions defining a conduit lumen. A plug may be seated in the conduit lumen and secured to an interior surface of the delivery wire conduit. A core wire may be disposed in the conduit lumen and having a distal end extending through the plug, so that the plug secures the core wire to the delivery wire conduit. The plug may form a substantially fluid tight seal of the conduit lumen. In one such embodiment, the plug comprises a stopper coil and an adhesive wicked into the stopper coil. In one such embodiment, the proximal rigid segment comprises a proximal region of the distal coil portion and a reflowed polymer section covering the proximal region, the flexible segment comprises an unsheathed middle region of the distal coil portion, and the distal rigid segment comprises the plug and a distal region of the distal coil portion covering the plug.
In another embodiment, the delivery wire assembly has a distal end portion comprising first, second and third rigid segments, along with first and second flexible segments, wherein the first flexible segment is disposed between the first and second rigid segments, and the second flexible segment is disposed between the second and third rigid segments. Such embodiment may further include a delivery wire conduit having a proximal tubular portion coupled to a distal coil portion, the respective tubular and coil portions defining a conduit lumen. A plug may be seated in the conduit lumen and secured to an interior surface of the delivery wire conduit. A core wire may be disposed in the conduit lumen and having a distal end extending through the plug, so that the plug secures the core wire to the delivery wire conduit. The plug may form a substantially fluid tight seal of the conduit lumen.
In one such embodiment, the plug includes a stopper coil and an adhesive. The stopper coil has a proximal open pitch area, a closed pitch area disposed distal to the proximal open pitch area, and a distal open pitch area disposed distal to the closed pitch area, the adhesive wicked into the proximal and distal open pitch areas, the closed pitch area disposed between the proximal and distal open pitch areas. The plug may also comprise a thin polymer tube disposed around the part of the core wire covered by the closed pitch area of the stopper coil. In such embodiments, the first rigid segment may comprise a proximal region of the distal coil portion and a reflowed polymer section covering the proximal region, and the first flexible segment may comprise an unsheathed mid-proximal region of the distal coil portion. In some such embodiments, the second rigid segment comprises the proximal open pitch area of the plug and a middle region of the distal coil portion covering the proximal open pitch area of the plug, the second flexible segment comprises the closed pitch area of the plug and a mid-distal region of the distal coil portion covering the closed pitch area of the plug, and the third rigid segment comprises the distal open pitch area of the plug and an unsheathed distal region of the distal coil portion covering the plug.
In still another embodiment, a delivery wire assembly for delivery of an occlusive device to a location in a patient's vasculature includes an assembly proximal end and an assembly distal end, the assembly distal end comprising a proximal rigid segment, a proximal flexible segment disposed distal to the proximal rigid segment, a distal rigid segment disposed distal to the proximal flexible segment, and a distal flexible segment disposed distal to the distal rigid segment, wherein the proximal flexible segment is disposed between the proximal and distal rigid segments. The delivery wire assembly further comprises a delivery wire conduit having a proximal tubular portion coupled to a distal coil portion, the respective tubular and coil portions defining a conduit lumen. A plug is seated in the conduit lumen and secured to an interior surface of the delivery wire conduit. A core wire is disposed in the conduit lumen and having a distal end extending through the plug, so that the plug secures the core wire to the delivery wire conduit. The plug may form a substantially fluid tight seal of the conduit lumen.
In one such embodiment, the plug comprises a stopper coil having an open pitch area and a closed pitch area disposed distal to the open pitch area, wherein an adhesive is wicked into the open pitch area. The proximal rigid segment comprises a proximal region of the distal coil portion and a reflowed polymer section covering the proximal region. The proximal flexible segment comprises an unsheathed mid-proximal region of the distal coil portion. The distal rigid segment comprises the open pitch area of the plug and a mid-distal region of the distal coil portion covering the open pitch area of the plug. The distal flexible segment comprises the closed pitch area of the plug and a distal region of the distal coil portion covering the closed pitch area of the plug.
Such embodiments may optionally further comprise a middle flexible segment disposed between the proximal flexible segment and the distal rigid segment, wherein the proximal flexible segment is disposed between the proximal rigid segment and the middle flexible segment. Again, the plug comprises a stopper coil and an adhesive, the stopper coil comprising a proximal closed pitch area, an open pitch area disposed distal to the proximal closed pitch area, and a distal closed pitch area disposed distal to the open pitch area, the adhesive wicked into the open pitch area, and the open pitch area disposed between the proximal and distal closed pitch areas.
In one such embodiment, the proximal rigid segment comprises a proximal region of the distal coil portion and a reflowed polymer section covering the proximal region, the proximal flexible segment comprises an unsheathed mid-proximal region of the distal coil portion, the middle flexible segment comprises the proximal closed pitch area of the plug and a middle region of the distal coil portion covering the proximal closed pitch area of the plug, the distal rigid segment comprises the open pitch area of the plug and a mid-distal region of the distal coil portion covering the open pitch area of the plug, and the distal flexible segment comprises the distal closed pitch area of the plug and a distal region of the distal coil portion covering the distal closed pitch area of the plug.
Other and further aspects and features of the disclosed inventions will be evident from reading the following detailed description of the preferred embodiments, which are intended to illustrate, not limit, the disclosed inventions.
Referring now to the drawings in which like reference numbers represent corresponding parts throughout, and in which:
The inner lumen 106 may be advantageously coated with a lubricious coating such as PTFE to reduce frictional forces between the delivery catheter 100 and the respective delivery wire assembly 200 and occlusive coil 300 being moved axially within the lumen 106. The delivery catheter 100 may include one or more optional marker bands 108 formed from a radiopaque material that can be used to identify the location of the delivery catheter 100 within the patient's vasculature system using imaging technology (e.g., fluoroscope imaging). The length of the delivery catheter 100 may vary depending on the particular application, but generally is around 150 cm in length. Of course, other lengths of the delivery catheter 100 may be used with the system 10 described herein.
The delivery catheter 100 may include a distal end 104 that is straight as illustrated in
Still referring to
The delivery wire assembly 200 further includes a core wire 210 that extends from the proximal end 202 of the delivery wire assembly 200 to a location that is distal with respect to the distal end 204 of the delivery wire assembly 200. The core wire 210 is disposed within a conduit lumen 212 that extends within an interior portion of the delivery wire conduit 213. The core wire 210 is formed from an electrically conductive material such as stainless steel wire. The proximal end 214 of the core wire 210 (shown in phantom) is electrically coupled to an electrical contact 216 located at the proximal end 202 of the delivery wire assembly 200. The electrical contact 216 is configured to interface with a corresponding electrical contact (not shown) in the power supply 400. The core wire 210 is connected to the delivery wire conduit 213 as described below. The core wire 210 functions as a tether to the occlusive coil 300, such that when the delivery wire assembly 200 is pulled proximally, the occlusive coil 300 can also be withdrawn prior to coil detachment.
A portion of the core wire 210 is advantageously coated with an insulative coating 218. The insulative coating 218 may include polyimide. The entire length of the core wire 210 is coated with an insulative coating 218, except for the proximal end 214 of the core wire 210 that contacts the electrical contact 216, and a small region 220 located in a portion of the core wire 210 that extends distally with respect to the distal end 204 of the delivery wire assembly 200. This latter, “bare” portion of the core wire 210 forms the electrolytic detachment zone 220, which dissolves upon application of electrical current from the power supply 400.
Still referring to
The distal end 222 of the core wire 210 is connected to the proximal end 302 of the occlusive coil 300 at a junction 250. Various techniques and devices can be used to connect the core wire 210 to the occlusive coil 300, including laser melting, and laser tack, spot, and continuous welding. It is preferable to apply a non-conductive adhesive 240 to cover the junction 250 formed between the distal end 222 of the core wire 210 and the proximal end 302 of the occlusion coil 300. The non-conductive adhesive 240 may include an epoxy material which is cured or hardened through the application of heat or UV radiation. For example, the non-conductive adhesive 240 may include a thermally cured, two-part epoxy such as EPO-TEK® 353ND-4 available from Epoxy Technology, Inc., 14 Fortune Drive, Billerica, Mass. The non-conductive adhesive 240 encapsulates the junction 250 and increases its mechanical stability.
Still referring to
The power supply 400 preferably includes an onboard energy source, such as batteries (e.g., a pair of AAA batteries), along with drive circuitry 402. The drive circuitry 402 may include one or more microcontrollers or processors configured to output a driving current. The power supply 400 illustrated in
A visual indicator 406 (e.g., LED light) is used to indicate when the proximal end 202 of delivery wire assembly 200 has been properly inserted into the power supply 400. Another visual indicator 407 is activated if the onboard energy source needs to be recharged or replaced. The power supply 400 includes an activation trigger or button 408 that is depressed by the user to apply the electrical current to the sacrificial electrolytic detachment zone 220. Once the activation trigger 408 has been activated, the driver circuitry 402 automatically supplies current until detachment occurs. The drive circuitry 402 typically operates by applying a substantially constant current, e.g., around 1.5 mA. The power supply 400 may include optional detection circuitry 410 that is configured to detect when the occlusive coil 300 has detached from the core wire 210. The detection circuitry 410 may identify detachment based upon a measured impedance value. A visual indicator 412 may indicate when the power supply 400 is supplying adequate current to the sacrificial electrolytic detachment zone 220. Another visual indicator 414 may indicate when the occlusive coil 300 has detached from the core wire 210. As an alternative to the visual indicator 414, an audible signal (e.g., beep) or even tactile signal (e.g., vibration or buzzer) may be triggered upon detachment. The detection circuitry 410 may be configured to disable the drive circuitry 402 upon sensing detachment of the occlusive coil 300.
The power supply 400 may also contain another visual indicator 416 that indicates to the operator when non-bipolar delivery wire assembly is inserted into the power supply 400. As explained in the background above, non-bipolar delivery wire assemblies use a separate return electrode that typically is in the form of a needle that was inserted into the groin area of the patient. The power supply 400 is configured to detect when a non-bipolar delivery wire assembly has been inserted. Under such situations, the visual indicator 416 (e.g., LED) is turned on and the user is advised to insert the separate return electrode (not shown in
Still referring to
A ground contact 246 for the second conductive path 244 may be disposed on a proximal end of the tubular portion 206 of the delivery wire conduit 213. In one embodiment, the ground contact 246 is simply an exposed portion of the tubular portion 206 since the tubular portion 206 is part of the second conductive path 244. For instance, a proximal portion of the tubular portion 206 that is adjacent to the electrical contact 216 may be covered with an insulative laminated polymer sheath 207, such as laminated Pebax®, as illustrated in
The ground contact 246 is configured to interface with a corresponding electrical contact (not shown) in the power supply 400 when the proximal end 202 of the delivery wire assembly 200 is inserted into the power supply 400. The ground contact 246 of the second conductive path 244 is, of course, electrically isolated with respect to the electrical contact 216 of the first conductive path 242.
As seen in
The core wire 210, which runs through the delivery wire conduit 213, terminates at electrical contact 216 at one end and extends distally with respect to the distal coil portion 208 of the delivery wire conduit 213. The core wire 210 is coated with an insulative coating 218 such as polyimide except at the electrolytic detachment zone 220 and the proximal segment coupled to the electrical contact 216. The electrolytic detachment zone 220 is located less than half a millimeter (e.g., about 0.02 mm to about 0.2 mm) distally with respect to the distal end of the distal coil portion 208. The core wire 210 may have an OD of around 0.00175 inches.
As shown in
In the embodiment depicted in
The laminated polymer sheath 207 may be formed from a polyether block amide plastic material (e.g., Pebax® 7233 lamination). The laminated polymer sheath 207 is formed from a polymer tube that is heat laminated to the proximal tubular portion 206 adjacent part of the distal coil portion 208 of the delivery wire conduit 213. During heat lamination, heat is applied to a piece of balloon tubing overlying the polymer tube. In response to this heat treatment, the balloon tubing shrinks, transforming the polymer tube into the laminated polymer sheath 207. After lamination, the balloon tubing is peeled away from the laminated polymer sheath 207 and discarded. Then the polymer at the distal end (about 0.045 to about 0.065 inches from the distal tip) of the distal coil portion 208 is removed to expose the metallic surface of the distal coil portion 208 to form a return cathode. A reflowing process is then applied to distal end of the remaining polymer to form a smooth transition between the laminated and the non-laminated areas of the distal coil portion 208.
The reflowed section 260 may be formed from the polymer tube that was laminated around the proximal region 290 of the distal coil portion 208 of the delivery wire conduit 213. During reflowing, the polymer tube laminated around the proximal region 290 is reheated. The heat and dwell time of the heat are increased for reflowing with use of a hot air nozzle to taper and feather the reflowed section 260 distally. As shown in
Distal of the proximal region 290 of the distal coil portion 208 of the delivery wire conduit 213 is a middle region 294 of the distal coil portion 208 of the delivery wire conduit 213. The middle region 294 is an area of unsheathed coils from the distal coil portion 208 of the delivery wire conduit 213. The middle region 294 may have a length of around 0.010 inches. The unsheathed middle region 294 forms a flexible delivery wire assembly segment 272, as shown in
Distal of the middle region 294 of the distal coil portion 208 of the delivery wire conduit 213 is a distal region 298 of the distal coil portion 208 of the delivery wire conduit 213 that covers the plug 252. The distal region 298 may have a length less than about 0.039 inches and advantageously from about 0.020 to about 0.035 inches. The distal region 298 of the distal coil portion 208 of the delivery wire conduit 213, and the stopper coil 256 and adhesive 240 of the plug 256 form a distal rigid delivery wire assembly segment 274, as shown in
As shown in
Positioning of the flexible segment 272 between the proximal rigid segment 270 and the distal rigid segment 274 allows the two rigid segments 270, 274 to change orientation relative to each other about the articulation space of the flexible segment 272. The elimination of overlap between the reflowed section 260 and the plug 252 eliminates long stiff zones and extra stiff sub-zones. This configuration allows sectional bending as the delivery wire assembly 200 is navigated through the highly tortuous paths of a patient's vasculature.
In another embodiment shown in
The stopper coil 256 in the plug 252 in this embodiment is divided into three distinct areas: a proximal open pitch area 261; a distal open pitch area 263; and a closed pitch area 262 between the two open pitch areas 261, 263. The pitch of the stopper coil 256 in the open pitch areas 261, 263 is approximately 100%. The pitch of the stopper coil 256 in the closed pitch area 262 is approximately 0%. Consequently, when the adhesive 240 is applied to the stopper coil 256 during construction of the delivery wire assembly 200, the adhesive 240 wicks into the open pitch areas 261, 263, increasing their stiffness. Due to the lack of space between the coils in the closed pitch area 262, the adhesive 240 cannot wick into the closed pitch area 262. The resulting configuration is a flexible closed pitch area 262 between two open pitch areas 261, 263. As shown in
Distal of the mid-proximal region 292 of the distal coil portion 208 of the delivery wire conduit 213 is a middle region 294 of the distal coil portion 208 of the delivery wire conduit 213 that covers the proximal open pitch area 261 of the stopper coil 256. The middle region 294 may have a length less than about 0.039 inches and advantageously from about 0.010 to about 0.015 inches. The middle region 294 of the distal coil portion 208 of the delivery wire conduit 213, the proximal open pitch area 261 of the stopper coil 256, and the adhesive 240 wicked into the proximal open pitch area 261 form a middle rigid delivery wire assembly segment 278 (shown in
Distal of the mid-distal region 296 of the distal coil portion 208 of the delivery wire conduit 213 is a distal region 298 of the distal coil portion 208 of the delivery wire conduit 213 that covers the distal open pitch area 263 of the stopper coil 256. The distal region 298 may have a length less than about 0.039 inches and advantageously from about 0.020 to about 0.035 inches. The distal region 298 of the distal coil portion 208 of the delivery wire conduit 213, the distal open pitch area 263 of the stopper coil 256, and the adhesive 240 wicked into the distal open pitch area 263 form a distal rigid delivery wire assembly segment 274, as shown in
As shown in
In another embodiment, shown in
The stopper coil 256 in the plug 252 in this embodiment is divided into two distinct areas: an open pitch area 264; and a closed pitch area 262 distal to the open pitch area 264. The pitch of the stopper coil 256 in the open pitch area 264 is approximately 100%. The pitch of the stopper coil 256 in the closed pitch area 262 is approximately 0%. As described above, adhesive 240 will wick into the open pitch area 264, but not the closed pitch area 262, increasing the stiffness of the open pitch area 264. Distal of the mid-proximal region 292 of the distal coil portion 208 of the delivery wire conduit 213 is a mid-distal region 296 of the distal coil portion 208 of the delivery wire conduit 213 that covers the open pitch area 264 of the stopper coil 256. The mid-distal region 296 may have a length less than about 0.039 inches and advantageously from about 0.010 to about 0.020 inches. As shown in
Distal of the mid-distal region 296 of the distal coil portion 208 of the delivery wire conduit 213 is a distal region 298 of the distal coil portion 208 of the delivery wire conduit 213 that covers the closed pitch area 262 of the stopper coil 256. The distal region 298 may have a length of around 0.010 to around 0.020 inches. The distal region 298 of the distal coil portion 208 of the delivery wire conduit 213 and the closed pitch area 262 of the stopper coil 256 form a distal flexible delivery wire assembly segment 280, as shown in
As shown in
In another embodiment shown in
The stopper coil 256 in the plug 252 in this embodiment is divided into three distinct areas: a proximal closed pitch area 265; a distal closed pitch area 266; and an open pitch area 264 between the two closed pitch areas 265, 266. The pitch of the stopper coil 256 in the open pitch area 264 is approximately 100%. The pitch of the stopper coil 256 in the closed pitch areas 265, 266 is approximately 0%. As described above, adhesive 240 will wick into the open pitch area 264, but not the closed pitch areas 265, 266, increasing the stiffness of the open pitch area 264.
Distal of the mid-proximal region 292 of the distal coil portion 208 of the delivery wire conduit 213 is a middle region 294 of the distal coil portion 208 of the delivery wire conduit 213 that covers the proximal closed pitch area 265 of the stopper coil 256. The middle region 294 may have a length of around 0.010 inches. The middle region 294 of the distal coil portion 208 of the delivery wire conduit 213 and the proximal closed pitch area 265 of the stopper coil 256 form a middle flexible delivery wire assembly segment 282, as shown in
Distal of the middle region 294 of the distal coil portion 208 of the delivery wire conduit 213 is a mid-distal region 296 of the distal coil portion 208 of the delivery wire conduit 213 that covers the open pitch area 264 of the stopper coil 256. The mid-distal region 296 may have a length less than about 0.039 inches and advantageously from about 0.010 to about 0.020 inches. The mid-distal region 296 of the distal coil portion 208 of the delivery wire conduit 213, the open pitch area 264 of the stopper coil 256, and the adhesive 240 wicked into the open pitch area 264 form a distal rigid delivery wire assembly segment 274, as shown in
Distal of the mid-distal region 296 of the distal coil portion 208 of the delivery wire conduit 213 is a distal region 298 of the distal coil portion 208 of the delivery wire conduit 213 that covers the distal closed pitch area 266 of the stopper coil 256. The distal region 298 may have a length of around 0.010 inches. The distal region 298 of the distal coil portion 208 of the delivery wire conduit 213 and the distal closed pitch area 266 of the stopper coil 256 collectively form a distal flexible delivery wire assembly segment 280, as shown in
As shown in
While various embodiments of the disclosed inventions have been shown and described, they are presented for purposes of illustration, and not limitation. Various modifications may be made to the illustrated and described embodiments (e.g., the dimensions of various parts) without departing from the scope of the disclosed inventions, which are limited and defined only by the following claims and their equivalents.
The present application claims the benefit under 35 U.S.C. §119 to U.S. provisional patent application Ser. No. 61/262,394, filed Nov. 18, 2009. The foregoing application is hereby incorporated by reference into the present application in its entirety.
Number | Date | Country | |
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61262394 | Nov 2009 | US |