Patent Application
20200078024
The present invention relates to medical devices and, more particularly, to occluding devices and methods of making the devices.
Embolization coils (e.g. pushable fibered coils) have been used as a primary occluding device for treatment of various arteriovenous malformations (AVM) and varicoceles, as well as for many other arteriovenous abnormalities in the body. Occluding devices are also used to repair abnormal shunts between arteries and veins, prevent or reduce blood flow to tumors, stop hemorrhaging as a result of trauma, and stabilize aneurysms to prevent rupture. Embolization coils can be used to provide occlusion of fluid flow through a body vessel. Embolization coils are preferably used to occlude fluid flow through a body vessel due to a blood vessel malformation occurring in the brain, like aneurysms, or other part of the body. Occluding devices may vary for different purposes, e.g., to hold the device in place within a cavity or vessel and to pack the device within the vessel for enhanced occlusion.
Embolization coils may be configured in a variety of sizes and may be made of several different materials including stainless steel and platinum. Embolization coils can be built out of a main coil and an end coil. The end coil is a larger diameter coil and the main coil has a smaller diameter. The purpose of the end coil is to prevent a wire guide from getting wedged between the embolization coil and a catheter tubing when pushing the embolization coil through a catheter.
The current process for making an embolization coil with an end coil is to make the main coil and the end coil separately, and then attach the end coil to the proximal end of the main coil. The attachment can be a friction fit, a laser welded, adhesive, welded, soldered connection of the end coil to the main coil. However, there is a risk of detachment resulting in the end coil coming off the embolization coil and becoming a loose part. The separate processing steps of making the embolization coil may also involve an undesirable amount of time and cost.
Accordingly, improvements can be made in embolization coils and the process of making such coils to simplify the process and to save time and cost.
The present disclosure provides an improved occluding device for occlusion of fluid flow through a lumen of a body vessel. The occluding device includes a main coil having first primary coil windings with a first coil diameter and an end coil having second primary coil windings with a second coil diameter. The main coil is formed into a secondary coil with various shapes. The main coil has an initial tension of between about 5 and 60 grams of weight, and the initial tension represents an amount of force necessary to cause a 4 centimeter length of the main coil to begin to elongate.
The second coil diameter of the end coil is greater than the first coil diameter of the main coil so the end coil can fit more tightly within a catheter tubing to prevent a wire guide being stuck between the occluding device and the catheter tubing.
The main coil and the end coil are monolithically formed from a single wire so the process of production is simplified and the risk of detachment of the end coil or main coil from the occluding device is avoided.
In one aspect, the main coil has a uniform first coil diameter and the end coil has a uniform second coil diameter. In other aspects, the main coil and the end coil each can have varied coil diameters.
The end coil can have a tapered shape such that the end coil increases its diameter gradually from the first coil diameter to the second coil diameter. The end coil can also taper twice such that the end coil increases its diameter gradually from the first coil diameter to the second coil diameter and then decreases gradually from the second coil diameter. The tapered shape of the end coil allows the primary windings with smaller diameter to fill the space in the end coil lumen so the wire guide does not get stuck easily between the coil windings and the catheter tubing. The wire guide can be advance more easily.
The end coil can also have one or a plurality of uniform portions with smaller coil diameter(s) than the second diameter to allow the one or more plurality of uniform portions to fill the lumen of the end coil portion with the second diameter.
The end coil can also have sections with offsetting central axes. One central axis of the end coil can be coincident with a central axis of the main coil and another central axis of the end coil can be parallel to the central axis of the main coil.
The present disclosure also includes an improved method of manufacturing the occluding device. The method includes winding a metal wire having a first portion and a second portion to form a main coil in the first portion, winding the main coil to a secondary coil, and winding the second portion of the metal wire to form an end coil. The main coil has first primary coil windings forming a first primary coil body with a first coil diameter, and the main coil has an initial tension of between about 5 and 60 grams of weight. The end coil has second primary coil windings forming a second primary coil body with a second coil diameter greater than the first coil diameter. The method provides a continuous process to make the occluding device with a main coil and an end coil from a single wire.
The present disclosure also provides a method of manufacturing at least two occluding devices for occlusion of fluid flow through a lumen of a body vessel in a continuous process. The method includes winding a metal wire having at least a first portion, a second portion and a third portion to form a first coil in the first portion having first primary coil windings with a first coil diameter, winding the second portion of the metal wire to form a second coil having second primary coil windings with a second coil diameter different from the first coil diameter, winding the third portion of the metal wire to form a third coil having third primary coil windings with a third coil diameter, and cutting the second coil to form a first occluding coil and a second occluding coil. The first occluding coil includes the first portion and one part of the second portion, and the second occluding coil has the third portion and the other part of the second portion. At least one of the first, second and third coils has an initial tension of between about 5 and 60 grams of weight.
To make multiple occluding devices, the method further includes continuing winding the metal wire to form multiple coils, and cutting the multiple coils to provide multiple embolization coils. Each of the embolization coils includes a portion of at least two of the multiple coils, and the at least two of the multiple coils have different coil diameters.
Other objects, systems, methods, features and advantages of the invention will become apparent to one of ordinary skill in the art from consideration of the following description and the appended claims when taken in connection with the accompanying drawings.
The invention can be better understood with reference to the following figures and description. The components in the figures are not necessarily drawn to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.
The present disclosure provides a medical embolization coil with an end coil and a main coil and a method of making such a coil. The materials, methods, figures, and examples disclosed herein are illustrative only and not intended to be limiting.
In the present application, the term “proximal” refers to a direction that is generally towards a physician during a medical procedure, while the term “distal” refers to a direction that is generally towards a target site within a patient's anatomy during a medical procedure. The terms “substantially” or “about” as used herein include variations in the recited characteristic or quantity that are functionally equivalent to the quantity recited, such as an amount that is equivalent to the quantity recited for an intended purpose or function. In the case of a numerical quantity, the terms “substantially” or “about” shall mean a range consisting of a value 20% less than the recited value to a value 20% greater than the recited value, inclusive.
With reference to the
The two coils 12, 14 have different coil diameters.
The embolization coil 10 can be further curled to form a secondary shape.
Main coil 12 may have a pre-curled tension to facilitate main coil 12 being curled within the body vessel. The pre-curled tension, sometimes referred to as initial tension, may be defined to be the amount of force required to cause a 4 centimeter length of coil to begin to elongate. In one example, the main coil 12 has a pre-curled tension of between about 5 to 60 grams of weight, and preferably between about 10 to 30 grams of weight. In another example, the main coil 12 has a pre-curled tension of between about 65 to 120 grams of weight, and preferably between about 75 to 100 grams of weight. A coil having a pre-curled tension may be restrained substantially straight (see
The occluding device may include attached fibers extending therefrom. The fibers may be spaced apart from each other and held between primary windings 16 of the main coil 12, as shown in
As mentioned previously, the current process of making the embolization coil 10 by making separate main coil and end coil followed by an attachment step requires more time and cost and may have the risk of detachment. This disclosure provides a single process of making the embolization coil 10 by a continuous process from a single wire so the main coil and the end coil are monolithically formed. The process saves time and eliminates the risk of a loose part.
In this process, the end coil is incorporated into the embolization coil during the coiling process.
The material for the metal wire 50 is not particularly limited. Examples of the material may include stainless steel, platinum, tungsten, gold, tantalum, iridium, titanium, palladium, nickel, platinum alloys, cobalt-chromium-nickel-molybdenum-iron alloy, cobalt-chrome alloy, and Inconel alloy (Ni—Cr alloy). The cross-sectional shape of wire 50 is not limited to a circular shape. Various shapes like square shape, elliptical shape and other shapes may be selected.
Coil 60 can be made from a single wire 90 by a process similar to the process illustrated in the
Coil 60 can be used as an occluding device as it is. Multiple occluding devices 10 can also be made from coil 60. For this purpose, the length of each end coil 63, 65 is about 4-10 mm. The main coils 62 and 66 have a length that is similar to the length of main coil 12, and section 64 has a length that is about twice the length of main coil 12. Mandrel 70 is thus designed to have sections corresponding to the length requirement. After coil 60 is made, coil 60 is cut at line i at end coil section 63, line ii at main coil section 64, and line iii at end coil section 65 to afford four embolization coils. Each embolization coil has a main coil and an end coil, similar to embolization coil 10, with the proper lengths for the main coil and the end coil. Therefore, this continuous process of making embolization coil 10 with an end coil and a main coil saves multiple attachment steps and time to produce multiple embolization coils.
Longer coils with more main coil sections and end coil sections than coil 60 can be made with the continuous process. More embolization coils 10 can be made as illustrated above by cutting the long coil at multiple locations. Thus, more time, effort and cost can be saved.
Embolization coil 200 can be made from a single wire by a single process. During the process, in one approach, the coiling point is at a position furthest from the roller so the wire is deflected to have a coil diameter d2 first. The coiling point is then moved at a constant speed closer to the rollers while the wire is in contact with the coiling point. The wire is thus coiled to have tapered coil diameters to form the tapered end coil 214. Once the coiling point is at a position where the resulting coil diameter is d1, the coiling point stops moving and the wire is then deflected to the main coil 212 to have a constant diameter d1. In another approach, the coiling point can be at the position closest to the roller to make the main coil 212 first with diameter d1, and then is moved away from the rollers to produce the tapered end coil 214.
Embolization coil 300 can be made from a single wire by a similar process illustrated previously.
In this embodiment, the straight or uniform section 815, with its larger diameter, provides greater radial force or rigidity to allow the end coil to fit more tightly within the catheter tubing than embolization coils with only tapered end coil. Also, the straight portion helps positioning and orienting the whole embolization coil within the catheter, so the embolization coil is not tilted to either side. The tapered section 816 then can fill the lumen of section 815 to facilitate the wire guide advancing along the central axis of the embolization coil without being wedged between the coil and the catheter tubing. The combination of the straight portion and the tapered portion for the end coil thus benefits the deployment of the embolization coil.
Different embodiments of the embolization coil can be made from a single wire by a similar process illustrated previously. By adjusting the position or the point of contact of the wire with the coiling point, the resulting coil can have varying coil diameters suitable for particular purposes.
Multiple embolization coils of the above mentioned embodiments can be made with a continuous process. An embolization coil with multiple main coils and multiple end coil sections can be made with this process, and then the embolization coil can be cut at multiple sections to afford multiple coils having an end coil and a main coil.
The guide catheter 118 or sheath is made of polytetrafluoroethylene (PTFE) for percutaneously introducing the microcatheter 114 into the body vessel. Of course, any other suitable material may be used without falling beyond the scope or spirit of the present invention. The guide catheter 118 may have a size of between about 4-French to 8-French and allows the microcatheter 114 to be inserted therethrough to a desired location in the body vessel. The guide catheter 118 receives the microcatheter 114 and provides stability of the microcatheter 114 at a desired location within the body vessel. For example, the guide catheter 118 may stay stationary within a common visceral artery, e.g., a common hepatic artery, and adds stability to the microcatheter 114 as the microcatheter 114 is advanced through the guide catheter 118 to a point of occlusion in a connecting artery, e.g., the left or right hepatic artery.
When the distal end 124 of the microcatheter 114 is at the point of occlusion in the body vessel, the occluding device 10 is loaded at the proximal end 122 of the microcatheter 114 and is advanced through the microcatheter 114 for deployment through the distal end 124. In this embodiment, a push wire 126 is used to mechanically advance or push the occluding device 10 through the microcatheter 114. The size of the push wire 126 used depends on the diameter of the microcatheter 114.
It is to be understood that the body cavity embolization kit 110 described above is merely one example of a kit that may be used to deploy the occluding device 10 in a body vessel. Of course, other kits, assemblies, and systems may be used to deploy any embodiment of the occluding device without falling beyond the scope or spirit of the present invention.
As a person skilled in the art will readily appreciate, the above description is meant as an illustration of the implementation of the principles of this invention. This description is not intended to limit the scope of application of this invention in that the invention is susceptible to modification, variation, and change, without departing from the spirit of this invention, as defined in the following claims.
| Number | Date | Country | |
|---|---|---|---|
| 62730170 | Sep 2018 | US |
