Claims:WE CLAIM:
1. An embolization coil assembly (100) comprising:
a. an embolization coil (10) having a delivery configuration and a deployed configuration, the embolization coil (10) including:
i. at least one secondary coil (10a) having a proximal end (1) and a distal end (3), the at least one secondary coil (10a) being formed by reshaping a primary coil made from a superelastic shape memory material, wherein the at least one secondary coil (10a) includes a first section (10a1) and a second section (10a2), wherein the first section (10a1) and the second section (10a2) being linearly disposed in the delivery configuration, the first section (10a1) and the second section (10a2) attain a first predefined shape and a second predefined shape respectively in the deployed configuration;
b. a delivery system (20) for delivering the embolization coil (10), the delivery system (20) including:
i. a delivery wire (20a) including a distal end, the delivery wire (20a) having a tapered profile;
ii. at least one holding member (20b) including a first end and second end, the first end being attached to the distal end of the delivery wire (20a), the second end being attached to the proximal end (1) of the secondary coil (10a); and
iii. an introducer sheath (20c) for carrying the embolization coil (10) and the delivery wire (20a) at the target site.
2. The embolization coil assembly as claimed in claim 1 wherein, the embolization coil (10) is made from a monofilament wire made from one or more of nitinol, platinum cored nitinol, cobalt chromium, stainless steel, platinum, platinum-tungsten, and platinum-iridium material.
3. The embolization coil assembly as claimed in claim 1 wherein, the first pre-defined shape is an irregular shape.
4. The embolization coil assembly as claimed in claim 1 wherein, the second pre-defined shape is a helical shape.
5. The embolization coil assembly as claimed in claim 1 wherein, the distal end of the at least one secondary coil (10a) includes a coil tip (5) which prevents rupture of a lumen of diseased arteries or aneurysm walls.
6. The embolization coil assembly as claimed in claim 5 wherein, the coil tip (5) includes a dome-shaped first part (5a) and a rectangular-shaped second part (5b).
7. The embolization coil assembly as claimed in claim 1 wherein, the tapered profile includes a tapered diameter and a tapered length of a distal end of the delivery wire (20a) ranging from 0.15mm – 0.40mm and 200mm - 800mm respectively.
8. The embolization coil assembly as claimed in claim 1 wherein, the delivery wire (20a) is made of nitinol or platinum-tungsten or stainless steel material.
9. The embolization coil assembly as claimed in claim 1 wherein, an outer surface and/or an inner surface of the delivery wire (20a) is coated with a polytetrafluoroethylene (PTFE) coating.
10. The embolization coil assembly as claimed in claim 9 wherein, the thickness and the length of the said coating ranges from 0.0045mm - 0.0110mm and 1500mm - 2100mm respectively.
11. The embolization coil assembly as claimed in claim 1 wherein, the one or more holding members (30b) is made of platinum-tungsten, platinum-iridium, stainless steel, nitinol or platinum alloy material.
12. The embolization coil assembly as claimed in claim 1 wherein, the one or more holding members (30b) is formed using a threading concept.
13. A method of manufacturing an embolization coil (100), the method comprising:
i. coiling a primary coil using a round-shaped wire;
ii. reshaping the primary coil over a pre-defined mandrel (30) to form one or more secondary coils (10a) , each secondary coil (10a) having a distal end, a first section (10a1) and a second section (10a2);
iii. annealing the secondary coil (10a) to maintain the shape of the secondary coil (10a); and
iv. attaching a coil tip (5) to the distal end of the secondary coil (10a) to form an embolization coil (10).
14. The method of manufacturing the embolization coil (10) as claimed in claim 13 wherein, the primary coil is fabricated using micro coiling machines.
15. The method of manufacturing the embolization coil (10) as claimed in claim 13 wherein, the pre-defined mandrel (30) includes a knob shaped portion (30a) and a cylindrical shaped portion (30b).
16. The method of manufacturing the embolization coil (10) as claimed in claim 13 wherein, the annealing the secondary coil (10a) is carried out using a vacuum annealing machine.
17. The method of manufacturing the embolization coil (10) as claimed in claim 13 wherein, the annealing the secondary coil (10a) is conducted at a temperature ranging between 500°C - 700°C for a time period ranging between 10minutes - 50 minutes.
18. The method of manufacturing the embolization coil (10) as claimed in claim 18 wherein, the attaching the coil tip (5) is carried out via one of, a medical grade adhesive, ultraviolet gluing process or by spot welding process. , Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION:
EMBOLIZATION COIL ASSEMBLY AND METHOD OF PREPARATION THEREOF
2. APPLICANT:
Meril Life Sciences Pvt. Ltd., an Indian company of the address Survey No. 135/139 Bilakhia House, Muktanand Marg, Chala, Vapi- 396191, Gujarat

The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
[001] The present invention relates to a medical device, more specifically, the present invention relates to an embolization coil assembly.
BACKGROUND
[002] Intracranial aneurysm refers to a bulge or ballooning inside a blood vessel of the brain. The intracranial aneurysm may leak or rupture the blood vessel causing bleeding inside the brain. The intracranial aneurysm may occur inside a neurovasculature, generally at the vessel branch points. Aneurysms of anterior neurovasculature may include ICA (Internal Carotid Artery) aneurysms, superior hypophysial artery aneurysms, ophthalmic artery aneurysms, anterior choroidal aneurysms, etc. Aneurysms of posterior neurovasculature may include anterior inferior cerebellar artery (AICA) aneurysms, posterior inferior cerebellar artery (PICA) aneurysms, superior cerebellar artery (SCA) aneurysms, etc.
[003] There are various methods which are utilized for the treatment of aneurysms for example, surgical clipping across artery which feeds the aneurysm, coiling method, glue, mesh stents flow diversion, etc. The coiling method may include utilization of an embolization coil. The coiling procedure is a minimally invasive procedure to treat an aneurysm. The said procedure is performed by filling aneurysm with coils in order to close an aneurysm sac and reduce the risk of bleeding. The said procedure is performed from within the artery of a patient (endovascular) through a steerable catheter inserted into the blood stream at the groin and guided to the brain of the patient. The coiling procedure reduces rupturing of the aneurysm during surgery which results in faster embolization of aneurysm without affecting the flow of blood in a parent artery or in the aneurysm. The shape and size of the embolization coil depends upon a target site (i.e. the site of the intracranial aneurysm) at the intracranial arteries and/or in the aneurysm sacs for the embolization of intracranial aneurysm or neurovascular sites.
[004] Conventionally, several shapes of an embolization coil have been developed based on a treatment condition (i.e. deformed anatomical structure of the intracranial arteries). The said conventional coils are available in as framing coils and filling coils in order to treat an intracranial aneurysm. First, one or more framing coils are deployed at a target site followed by the deployment of the filing coil(s). Hence, in the conventional process, multiple framing coils as well as filling coils are required to deploy in order to treat the intracranial aneurysm. The deployment of the multiple coils increases the chances of migration inside a patient’s body.
[005] In the coiling procedure, deployment of the embolization coil plays a critical role including the coil release from the delivery system. The chances of aneurysm rupture and improper framing and filling of the embolization coil is a major problem in the coiling procedures. Improper deployment of the embolization coil may cause development of a new aneurysm at the treatment site.
[006] Therefore, an embolization coil and a delivery system of the said coil which overcomes the drawbacks of the conventional assemblies are required to be devised.
SUMMARY
[007] The present invention discloses an embolization coil assembly. The said assembly includes an embolization coil having a delivery configuration and a deployed configuration. The embolization coil includes at least one secondary coil. The secondary coil has a proximal end and a distal end. The secondary coil is formed by reshaping a primary coil made from a superelastic shape memory material. The secondary coil includes a first section and a second section. The first section and the second section is linearly disposed in the delivery configuration. The first section and the second section attain a first predefined shape and a second predefined shape respectively in the deployed configuration.
[008] The embolization coil is delivered using the delivery system. The delivery system includes a delivery wire having a distal end. The delivery wire has a tapered profile.
[009] Further, a holding member having a first end and second end is included in the embolization coil. The first end is attached to the distal end of the delivery wire while the second end is attached to the proximal end of the secondary coil. An introducer sheath for carrying the embolization coil and the delivery wire at the target site is also provided.
[0010] The embolization coil is manufactured using a pre-defined method. A primary coil is coiled using a round-shaped wire. The primary coil is then reshaped over a pre-defined mandrel to form one or more secondary coils. Each secondary coil has a distal end, a first section and a second section.
[0011] The secondary coil is then annealed to maintain the shape of the secondary coil. A coil tip is subsequently attached to the distal end of the secondary coil to form an embolization coil.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[0013] Fig. 1 depicts an embolization assembly 100 in accordance with an embodiment of the present invention.
[0014] Fig. 2 depicts an embolization coil 10 in accordance with an embodiment of the present invention.
[0015] Fig. 2a represents the embolization coil 10 in delivery configuration in accordance with an embodiment of the present invention.
[0016] Fig. 2b depicts the embolization coil 10 in deployed configuration in accordance with an embodiment of the present invention.
[0017] Fig. 2c depicts the embolization coil 10 during deployment in accordance with an embodiment of the present invention.
[0018] Fig. 3 depicts a coil tip 5 in accordance with an embodiment of the present invention.
[0019] Fig. 4 illustrates the steps involved in manufacturing the embolization coil 10 in accordance with an embodiment of the present invention.
[0020] Fig. 4a depicts a mandrel 30 for the formation of the embolization coil 10 in accordance with an embodiment of the present invention.
[0021] Fig. 5 indicates the steps involved in loading and unloading the embolization coil 10 in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0022] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like; Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.
[0023] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings, however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[0024] In accordance with the present disclosure, an embolization coil assembly is disclosed. The embolization coil assembly includes an embolization coil and a delivery system. The embolization coil of the present invention is utilized to treat a ruptured intracranial aneurysm and/or other abnormalities which include, without limitation, arteriovenous malformation (AVM), arteriovenous fistula (AVF), etc., in the neuro-vasculature. The embolization coil of the present invention includes a delivery configuration and a deployed configuration.
[0025] The embolization coil of the present invention is a combination coil which includes a secondary coil having one or more of, a first section and a second section. The secondary coil is developed from a primary coil by reshaping the same over a pre-defined mandrel.
[0026] The first section and the second section of the present invention correspond to a first pre-defined shape (hereon referred as an irregular shape) and a second pre-defined shape (hereon referred as a helical shape) respectively. In the delivery configuration, the embolization coil is axially stretched such that the first section and the second section are linearly disposed within a lumen of an introducer sheath.
[0027] In the deployed configuration, the first section and the second section regain their original shape and transform to the irregular-shape and the helical-shape respectively.
[0028] The first section of the embolization coil acts as a framing structure. It should be noted that ‘framing’ in the present description corresponds to covering the periphery of the target site.
[0029] The second section is a filling structure. It should be noted that ‘filling’ in the present description corresponds to stuffing the remaining portion of the target site partially/completely.
[0030] Such combination of the first section and the second section reduces the number of coils to be used to fill the aneurysm, ensures proper filing of the aneurysm and reduces the time of deployment of the embolization coil.
[0031] The delivery system of the present invention is utilized to deliver the embolization coil at a target site. The delivery system includes a delivery wire, one or more holding members and an introducer sheath. The delivery wire helps to advance the embolization coil from the microcatheter towards the target site. The holding member is utilized to hold the embolization coil and mechanically detach the said coil at the target site. The introducer sheath defines a lumen which carries the embolization coil and the delivery wire.
[0032] Now referring specifically to the drawings, Fig. 1 depicts an embolization coil assembly 100. As shown in FIG. 1, the embolization coil assembly 100 includes an embolization coil 10 (clearly depicted in FIGs. 2, 2a & 2b) and a delivery system 20.
[0033] The embolization coil 10 may be utilized to treat a ruptured intracranial aneurysm and/or other abnormalities, without limitation, arteriovenous malformation (AVM), arteriovenous fistula (AVF), etc., in the neuro-vasculature.
[0034] The embolization coil 10 of the present invention as disclosed above is easy to use and requires minimal preparation time. The embolization coil 10 being fully retractable helps in easy repositioning until the embolization coil 10 is placed to achieve optimal occlusion in cases where very precise placement of the embolization coil 10 is crucial.
[0035] The embolization coil 10 may be made from one of, a monofilament or multifilament wires. In an embodiment, the embolization coil 10 is made of a monofilament wire in order to form a spring-like structure. The wires may include a superelastic shape memory material such as, without limitation, nitinol, platinum cored nitinol, cobalt chromium, stainless steel, platinum, platinum-tungsten, platinum-iridium, etc.
[0036] In an embodiment, the embolization coil 10 is made of soft platinum-tungsten material. In an embodiment, the embolization coil 10 includes at least 90% - 92% of platinum and at least 8% - 10% of tungsten. The platinum-tungsten material helps in tight packing of the embolization coil 10 within the aneurysm.
[0037] As submitted above, the embolization coil 10 includes a delivery configuration (as shown in FIG. 1 & 2a) and a deployed configuration (as shown in FIG. 2b). The embolization coil 10 of the present invention is a self-expanding device. Owing to the superelastic shape memory material with which it is formed, the embolization coil 10 transforms from its delivery configuration to its deployed configuration at the time of its implantation at the target site.
[0038] In an embodiment, the embolization coil 10 is formed by reshaping one or more primary coils (elaborated below).
[0039] As depicted in FIGs. 2, 2a and 2b, the embolization coil 10 of the present invention includes at least one secondary coil 10a having a proximal end 1 and a distal end 3. The proximal end 1 of the secondary coil 10a may be attached to the delivery system 20. The distal end 3 of the secondary coil 10a may include a coil tip 5 as shown in FIG. 2a.
[0040] The coil tip 5 may help to prevent rupture of the lumen of diseased arteries or aneurysm walls at the time of deployment of the embolization coil 10. Further, the coil tip 5 acts as a marker for visualization of the embolization coil 10 under fluoroscopic examination.
[0041] The coil tip 5 may be made of one or more radiopaque materials, which include without limitation, stainless steel, nitinol, platinum-iridium, platinum-tungsten, etc. In an embodiment, the coil tip 5 is made of platinum-iridium material. In an embodiment, the platinum-iridium material is composed of at least 90% - 92% of platinum and at least 8% - 10% of iridium. The said material is selected as per a standard, say, ASTM B-684. The iridium material in combination with platinum material provides strength to the coil tip 5 and also aids in conferring radiopacity to the coil tip 5.
[0042] The coil tip 5 may include a first part 5a and a second part 5b as shown in FIG. 3. In an embodiment, the first part 5a is a dome-shaped structure and the second part 5b is a cylindrical structure. The second part 5b of the coil tip 5 may be positioned at the distal end 3 of the embolization coil 10. Owing to the dome-shaped first part 5a, any rupture of the lumen of intracranial arteries or the aneurysm wall is prevented at the time of deployment of the embolization coil 10. The second part 5b of the coil tip 5 may extend from the distal end 3 towards the proximal end 1 within a portion of a hollow cavity as defined by the embolization coil 10. In an embodiment, the second part 5b of the coil tip 5 extends till a distance of 2mm to 10mm distance from the distal end 3 within the embolization coil 10.
[0043] The dimensions of the first part 5a and the second part 5b may be dependent upon the dimensions of the embolization coil 10.
[0044] The secondary coil 10a includes a wire diameter in the range of 0.01 - 0.10mm. In an embodiment, the wire diameter is 0.05mm. In an embodiment, the wire diameter of the primary coil and the secondary coil 10a are same.
[0045] As shown in FIGs. 2 and 2b, the secondary coil 10a includes one or more of, a first section 10a1 and a second section 10a2. In an embodiment, the secondary coil 10a includes one first section 10a1 and one second section 10a2.
[0046] The first section 10a1 may be disposed towards the distal end 3 while the second section 10a2 may be disposed towards the proximal end 1.
[0047] The shape of the first section 10a1 and the second section 10a2 of the secondary coil 10a may be based on a treatment condition i.e. the deformed anatomical structure of the target site. Though the shape of the first and second sections 10a1, 10a2 may be any conventional shape, the following description defines the shape of the first section 10a1 to be irregular while the second section 10a2 of the secondary coil 10a includes a helical shape.
[0048] As shown in FIGs. 1 and 2a, for ease of delivery, the embolization coil 10 is axially stretched and then loaded on the delivery system 20. Hence, the axial stretching of the embolization coil 10 causes the embolization coil 10 to be disposed in a linear manner. Therefore, the first section 10a1 and the second section 10a2 are deformed with respect to their original shapes and hence, do not have an irregular shape and a helical shape respectively. Such manner of disposition of the embolization coil 10 is maintained with the help of the introducer sheath.
[0049] As soon as the introducer sheath is retrieved back and/or delivery wire 20a is pushed forward at the time of deployment, the embolization coil 10 may project out of the introducer sheath as shown in FIG. 2c. Owing to its superelastic and shape memory property, the embolization coil 10 gradually expands/opens up in such a way that the original shapes of the first and second sections 10a1 and 10a2 are regained. Hence, the first and second sections 10a1 and 10a2 transform to irregular shape and helical shape respectively.
[0050] As shown in FIG. 2b, the first section 10a1 of the secondary coil 10a is used to frame (outline) the target site. Further, the first section 10a1 may also be utilized for holding and/or providing a support for other embolization coils that are subsequently delivered to the target site. The second section 10a2 of the secondary coil 10a is used to provide framework (filling) for the target site as shown in FIG. 2b. Further, the second section 10a2 may also be used to hold the other embolization coils at the target site.
[0051] Such combination of the first section 10a1 and the second section 10a2 reduces the number of coils to be used to fill the aneurysm, ensures proper filing of the aneurysm and reduces the time of deployment of the embolization coil 10.
[0052] In an embodiment, the first section 10a1 and the second section 10a2 have same softness and flexibility. In such a case, the secondary coil 10a includes a uniform coil pitch.
[0053] In an alternate embodiment, the first section 10a1 and the second section 10a2 have different softness and flexibility. The difference in the softness and flexibility of the first section 10a1 and the second section 10a2 may be obtained by incorporating different coil pitch in the secondary coil 10a. In an embodiment, the coil pitch length in the first section 10a1 is uniform which provides adequate strength and softness required to frame the target site. The coil pitch length is differentiated in the second section 10a2 of the secondary coil 10a so that the second section 10a2 is rendered very soft to fill the target site easily. Such variety of the coil pitch length difference provides maximum filling of the target site and further reduces the chances of generation of subsequent aneurysms at the target site.
[0054] The length of the first section 10a1 ranges from 5mm - 700mm. In an embodiment, the diameter of the first section 10a1 is 1mm – 35mm.
[0055] The length of the second section 10a2 ranges from 1mm – 700mm. In an embodiment, the diameter of the second section 10a2 is 0.5mm – 30mm.
[0056] The delivery system 20 of the present invention as disclosed in FIG. 1 is utilized for deployment of the embolization coil 10. The delivery system 20 ensures easy, smooth and hassle free delivery of the embolization coil 10 at the target site. The delivery system 20 of the embolization coil 10 may be compatible with a 2.4Fr - 2.7Fr microcatheter with a length of 190cm-195cm.
[0057] The delivery system 20 of the present invention may include without limitation, a delivery wire 20a, one or more holding members 20b and an introducer sheath 20c.
[0058] The delivery wire 20a may be made of without limitation, nitinol or platinum-tungsten or stainless steel material. In an embodiment, the delivery wire 20a is made of stainless steel 304. In an embodiment, the delivery wire 20a includes a tapered configuration.
[0059] The diameter of the delivery wire 20a at distal end maybe in the range of 0.12mm - 0.30mm, more preferably 0.15mm - 0.25mm. The diameter of the delivery wire 20a at proximal end maybe in the range of 0.30mm - 0.50mm, more preferably 0.35mm – 0.45mm. In an embodiment, the diameter of the distal end and the proximal end is 0.19 mm and 0.40mm respectively.
[0060] The length of the delivery wire 20a maybe in the range of 1600mm – 2200mm, more preferably 1800mm – 2000mm. In an embodiment, the length of the delivery wire 20a is 1900mm. The length of the tapered portion in delivery wire 20a may be in the range of 200mm – 800mm, more preferably 400mm – 600mm. In an embodiment, the length of the tapered portion in delivery wire 20a is 500mm.
[0061] The delivery wire 20a may be coated with a polymeric coating. The delivery wire may be coated with polytetrafluoroethylene (PTFE), hydrophilic coating (i.e. 65% - 75% Polymethyl Acrylate, 1% -3% aliphthatic polyisocynate, 25% - 35% hyaluronic acid and 0.3% - 0.5% cross linking agent aziridine), etc. In an embodiment, the delivery wire 20a is coated with a polytetrafluoroethylene (PTFE) coating.
[0062] The thickness of the polymeric coating may be in the range of 0.0045mm - 0.0110mm. In an embodiment, the thickness of the polymeric coating is 0.00762mm. The length of the polymeric coating may be in the range of 1500mm - 2100mm, more preferably 1700mm - 1900mm. In an embodiment, the length of the polymeric coating is 1800mm. The said coating decreases the delivery friction and retraction friction of the delivery system 20.
[0063] The tapered configuration of the delivery wire 20a along with the polymeric coating provides flexibility and enhanced lubricity for easy movement of the delivery system 20 during its deployment through a tortuous vasculature. Hence, there is a significant decrease in delivery friction as well as retraction friction as compared to the conventional wires. The delivery wire 20a of the present invention further allows the delivery system 20 to retain its original shape. Further, the delivery wire 20a keeps the tip of the delivery system 20 in its desired position in the patient’s anatomy to facilitate accurate placement of the delivery system 20.
[0064] The delivery wire 20a may include, without limitation, a distal end and a proximal end (not shown). The distal end of the delivery wire 20a may be attached to one or more holding members 20b.
[0065] The one or more holding members 20b may include without limitation, a first end 20b1 and a second end 20b2 as shown in FIG. 1. The first end 20b1 of the one or more holding members 20b may be provided at the distal end of the delivery wire 20a. The attachment of the one or more holding members 20b with the distal end of the delivery wire 20a may be performed via one or more of, without limitation, spot welding process, a medical adhesive, a lock tie, etc.
[0066] The second end 20b2 may be attached to the proximal end 1 of the secondary coil 10.
[0067] The one or more holding members 20b is utilized for mechanically detaching the embolization coil 10 from the delivery system 20 once the said coil 10 reaches the target site.
[0068] The one or more holding members 20b may be made of without limitation, platinum-tungsten, platinum-iridium, stainless steel, nitinol or platinum alloy material. In an embodiment, the one or more holding members 20b is made of nitinol material. The said material helps to locate and finalize the detachment of the embolization coil 10 from the delivery system 20 under fluoroscopy. In another embodiment, the one or more holding members 20b is made of platinum-Iridium or platinum-tungsten material. The iridium or tungsten material in combination with platinum material provides strength to the one or more holding members 20b and also aids in radiopacity of the one or more holding members 20b under the fluoroscopic examination.
[0069] The one or more holding members 20b includes an outer diameter which may range from 0.20mm - 0.40mm, more preferably 0.25mm - 0.38mm. In an embodiment, the outer diameter of the one or more holding members 20b is one of, 0.2743mm, 0.2921mm, 0.3429mm or 0.3683mm. The one or more holding members 20b also includes an inner diameter which may range from 0.05mm to 0.35mm, more preferably 0.10mm - 0.33mm. In an embodiment, the inner diameter of the one or more holding members 20b is one of, 0.1210mm, 0.1921mm, 0.2921mm or 0.3175mm. The length of the one or more holding members 20b may range from 5mm - 25mm, more preferably 10mm - 20mm. In an embodiment, the length of the one or more holding members 20b is 15mm.
[0070] In an embodiment, the one or more holding members 20b is formed using the threading concept. The one or more holding members 20b includes different pitch arrangement for the threading mechanism. The pitch arrangement of the first end 20b1 of the one or more holding members 20b may be in the range of 0.02mm - 0.09mm, more preferably 0.04mm - 0.06mm. The pitch arrangement of the second end 20b2 of the one or more holding members 20b may be in the range of 0.05mm – 0.15mm, more preferably 0.08mm to 0.12mm. In an embodiment, the pitch arrangement of the first end 20b1 and the second end 20b2 of the one or more holding members 20b is 0.050mm and 0.100mm respectively.
[0071] The introducer sheath 20c carries the embolization coil 10 and the delivery wire 20a for placement into a lumen of the delivery system 20. The introducer sheath 20c may be a transparent or a translucent tube. In an embodiment, the introducer sheath 20c is a transparent tube including a lumen (not shown). The diameter of the lumen of the introducer sheath 20c may be in the range of 0.15mm - 0.75mm, more preferably 0.35mm - 0.55mm. In an embodiment, the diameter of the lumen is 0.45mm. The transparency of the introducer sheath 20c helps to inspect the location of the embolization coil 10 and the configuration of the embolization coil 10 within the introducer sheath 20c. The transparency of the introducer sheath 20c also helps to confirm the advancement of the embolization coil 10 during deployment.
[0072] The introducer sheath 20c may be a single-layered or multi-layered sheath. In an embodiment, the introducer sheath 20c includes a single layer configuration. The introducer sheath 20c may be made of without limitation, a polymeric material. The polymeric material may include without limitation, polytetrafluoroethylene (PTFE), polyimide or the mixture of PTFE-polyimide, polyamide or the mixture of nylon-polyamide and nylon. In an embodiment, the introducer sheath 20c is made of polyimide-PTFE blend or polytetrafluoroethylene (PTFE). The polyimide used for the formation of the single-layered introducer sheath 20c provides strength and integrity to the introducer sheath 20c. The polyimide also helps to prevent the deformation and kinking of the introducer sheath 20c during the deployment process of the embolization coil 10.
[0073] The introducer sheath 20c may have a wall thickness which may be in the range of 0.08mm - 0.50mm, more preferably 0.10mm - 0.30mm. In an embodiment, the wall thickness of the introducer sheath 20c is 0.20mm. The introducer sheath 20c may include a length which may be in the range of 700mm - 1500mm, more preferably 900mm - 1300mm. In an embodiment, the length of the introducer sheath 20c is 1200mm. The introducer sheath 20c may further include an outer diameter which may be in the range of 0.35mm - 0.95mm, more preferably 0.55mm - 0.75mm. In an embodiment, the outer diameter of the introducer sheath 20c is 0.65mm. The outer diameter of the introducer sheath 20c is lesser than an inner diameter of the delivery system 20 for ease in access through the delivery system 20 during the deployment of the embolization coil 10.
[0074] FIG. 4 represents the process for manufacturing the embolization coil 10 of the present invention. The manufacturing process commences at step 401 in which the primary coil is prepared. In an embodiment, the primary coil is fabricated using a coiling method.
[0075] The primary coil is made using micro coiling machines. The primary coil is formed using a round shaped wire. The materials utilized for fabricating the primary coil may include, without limitation, nitinol, platinum cored nitinol, cobalt chromium, stainless steel, platinum, platinum-tungsten, platinum-iridium, etc. In an embodiment, the primary coil is made from a platinum-tungsten wire. The diameter of the said wire may be in the range of 0.01 - 0.10mm. In an embodiment, the diameter of the wire is in the range of 0.04- 0.06mm, more specifically 0.05mm. The platinum-tungsten wire has a preferred mechanical property due to which it is utilized to make the primary coil. The tensile strength of the said wire may be in the range of 1.00-3.00kg/cm2. In an embodiment, the tensile strength of the said wire is in the range of 1.50kg/cm2 - 2.50kg/cm2, more specifically 1.90kg/cm2. The tensile strength of the primary coil plays an important parameter which maintains the strength and integrity of the embolization coil 10.
[0076] The diameter of the primary coil may be in the range of 0.10mm - 0.60mm, preferably, 0.20mm - 0.40mm. In an embodiment, the primary coil is formed having a diameter, for example, 0.27mm, 0.29mm, 0.31mm, 0.34mm, or 0.36mm. The diameter of the primary coil may provide sufficient coil embolization with a small number of coils. The integrity and strength of the primary coil is formed by the tensile strength of said coil. The tensile strength of the primary coil may be in the range of 0.30kg/cm2 - 0.60kg/cm2. In an embodiment, the tensile strength of the primary coil is in the range of 0.40 kg/cm2 - 0.50 kg/cm2, more specifically, 0.43kg/cm2.
[0077] The primary coil may further include a pitch length size which may be in the range of 0.01mm - 0.10mm. In an embodiment, the pitch length size of the primary coil is in the range of 0.04-0.06mm more specifically 0.05mm. The unique closed pitch structure of the primary coil that is coil pitch with uniform gap distance through the entire primary coil provides uniform softness of the coils which provides random coil movement by deflection according to the aneurysm wall. The random coil spreading with the closed pitch structure of the primary coil enables the said coil to change the direction during expansion according to the shape of the wall of the aneurysm.
[0078] The parameters of the primary coil play an important role in deliverability of the secondary coil 10a of the embolization coil 10. For example, such parameters may include, without limitation, composition, shape, size and stiffness of the wire which forms the primary coil, inner and/or outer diameter, length of the primary coil, uniformity of the windings of the primary coil, pitch of the primary coil windings, and/or spacing of the primary coil windings, etc.
[0079] At step 403, the primary coil is reshaped in order to form the one or more secondary coils 10a. For reshaping, the primary coil is cut into a specific length with the help of scissors and is then wound around a pre-defined mandrel 30 as depicted in Fig. 4a. However, mandrels of other shapes are also within the scope of the present invention.
[0080] The mandrel 30 may be made of any conventional material such as stainless steel, etc. In the embodiment as depicted in FIG. 4a, the mandrel 30 includes a knob shaped portion 30a and a cylindrical shaped portion 30b. The knob shaped portion 30a helps to provide a predefined shape and size to the primary coil so that the first section 10a1 of the secondary coil 10a may be formed. The knob shaped portion 30a includes a specific diameter and length. The diameter of the knob shaped portion 30a may range from 1mm -26mm. In an embodiment, the diameter of the knob shaped portion 30a is 1.30mm – 25.50mm. The length of the knob shaped portion 30a may range from 20mm – 80mm. In an embodiment, the length of the knob shaped portion 30a is 40mm – 60mm.
[0081] The cylindrical shaped portion 30b helps to provide a predefined shape and size to the primary coil so that the second section 10a2 of the secondary coil 10a may be formed. The cylindrical shaped portion 30b includes a specific outer diameter and length. The outer diameter of the cylindrical shaped portion 30b may range from 0.70mm – 21.0mm. In an embodiment, the outer diameter of the cylindrical shaped portion 30b is 0.85mm – 20.50mm. The length of the cylindrical shaped portion 30b may range from 50mm – 130mm. In an embodiment, the length of the cylindrical shaped portion 30b is 90mm – 110mm.
[0082] At step 405, the secondary coil(s) 10a formed at the step 403 is subjected to annealing in order to maintain the shape of the secondary coil 10a. In an embodiment, the annealing process is carried out with the help of a vacuum annealing machine. The mandrel 30 is loaded in a crucible which is a part of the annealing machine to hold the mandrel 30 inside a chamber. The crucible is inserted inside a quartz tube and the quartz tube is closed via a clamp attached to the said tube.
[0083] Further, the process parameters are set as per the requirement by the computer system in order to start the process. Vacuum is created for the process time. Post achieving the vacuum, a furnace moves slowly towards the quartz tube containing the crucible and stops near the quartz tube for some time then the actual process is started. The quartz tube holds the furnace as per the required time and temperature. In an embodiment, the temperature at which the secondary coil 10a undergoes the annealing process in the vacuum annealing machine is in the range of 500°C - 700°C, more preferably 550°C - 650°C. The time period at which the annealing is performed ranges from 10 minutes - 50 minutes, more preferably 20 minutes - 40minutes.
[0084] Post completion of the annealing process, the secondary coil 10a is cooled inside the vacuum annealing machine. The cooling of the secondary coil 10a may be carried out via a cooling fan. In an embodiment, when the temperature of the quartz tube reaches 100°C, the cooling fan automatically stops and vacuum is released. The clamps are opened and a sensor attached with the crucible is removed from the quartz tube.
[0085] At step 407, the attachment of the coil tip 5 with the secondary coil 10a takes place. The coil tip 5 is attached to the distal end 3 of the secondary coil 10a. The coil tip 5 may be attached to the secondary coil 10a via one of, a medical grade adhesive, ultraviolet gluing process or by spot welding process. In an embodiment, the coil tip 5 is attached to the secondary coil 10a via argon spot welding process. The said process may be performed with the help of a spot welding machine. The argon spot welding process includes various parameters such as pulse width, spot diameter, frequency and power of the spot welding machine.
[0086] The pulse width time of spot welding may range from 0.10millisecond - 1.3millisecond, the spot diameter may range from 0.20mm - 5.0mm, the frequency may be configured up to 2Hz and the power of the welding machine may range from 160volts - 340volts.
[0087] Post the attachment of the coil tip 5 to the secondary coil 10a, the embolization coil 10 is formed. The said embolization coil 10 may be transferred to a clean box for further use.
[0088] It should be noted that though the above process involves a single pre-defined mandrel 30 for preparation of a secondary coil 10a, as an alternate process, the secondary coil 10a may also be fabricated using two mandrels i.e. one knob shaped mandrel and other cylindrical shaped mandrel to form two different secondary coils which may later be combined to form a single secondary coil.
[0089] FIG. 5 of the present invention relates to the steps involved in the loading of the embolization coil 10 on the delivery system 20 and its subsequent deployment at the target site. At step 501, the embolization coil 10 is loaded inside the lumen of the introducer sheath 20c using the one or more holding members 20b. Loading the embolization coil 10 using the one or more holding members 20b is advantageous as it provides ease in operation and also significantly reduces the chances of any damage to the embolization coil 10. The proximal end 1 of the embolization coil 10 will alter as per the holding member 20b. The holding member 20b is manually attached or coupled with the embolization coil 10 by giving one or more turns of coil wire i.e. two different coils will merge at specific point which called as detachment zone.
[0090] Post loading of the embolization coil 10, the same may be deployed at the target site instantly or may be used in future.
[0091] At step 503, the delivery system 20 along with the embolization coil 10 is inserted within a lumen of a conventionally available micro-catheter and advanced towards the target site for positioning and subsequent deployment.
[0092] At step 505, once the embolization coil 10 is positioned at the target site, the proximal end of the delivery wire 20a is rotated or twisted by two or more turns to uncouple the one or more holding members 20b with the embolization coil 10. The delivery wire 20a is turned to detach the embolization coil 10 from the delivery wire 20a. In an embodiment, the one or more holding members 20b require three turns for detach the embolization coil 10 at the target site. In another embodiment, the delivery wire 20a is turned three or more times for detachment of the embolization coil 10 at the target site.
[0093] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used.