Source: https://patents.google.com/patent/US20100217236
Timestamp: 2018-02-23 21:02:17
Document Index: 109972785

Matched Legal Cases: ['art.\n8', 'art.\n9', 'art.\n10', 'art.\n16', 'art.\n17', 'art.\n20', 'art.\n21']

US20100217236A1 - Neurological apparatus - Google Patents
US20100217236A1
US20100217236A1 US12310207 US31020707A US20100217236A1 US 20100217236 A1 US20100217236 A1 US 20100217236A1 US 12310207 US12310207 US 12310207 US 31020707 A US31020707 A US 31020707A US 20100217236 A1 US20100217236 A1 US 20100217236A1
US12310207
A guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate ‘part having a composition of at least 80% tungsten carbide. The guide element may have a coating, such as a biocompatible plastics material which is more resilient than the elongate part.
The present invention relates to apparatus for use in neurosurgery, for positioning neurosurgical apparatus. In particular, it relates to a guide element for insertion into the brain for guiding tubular instruments such as catheters and guide tubes.
The blood-brain barrier represents a considerable hurdle to the delivery of therapeutic agents to the nervous system. The term therapeutic agents includes substances which have a therapeutic effect, such as pharmaceutic compounds, genetic materials, biologics (i.e. preparations synthesised from living organisms such as stem cells). The development of techniques to bypass this barrier could revolutionise the management of Parkinson's, Huntingdon's and Alzheimer's disease as well as Glioblastoma Multiforme. Novel agents that could potentially suppress or even reverse the underlying pathological processes of these conditions have been developed. However, the limitations of these therapeutic agents lie in their inability to cross the blood-brain barrier and consequently their failure to reach the necessary structures within the brain when delivered by conventional methods (e.g. oral or intravenously).
International patent application WO 03/077764 discloses the implantation of a catheter in a human or non-human brain for intraparenchymal drug delivery. A drug may thus be pumped intermittently or continuously through the catheter to the desired brain target.
WO 03/077764 further discloses a stereoguide used for the longitudinal guidance of instruments towards a target with the brain which defines an axis along which the instruments are inserted. The stereoguide is carried by a stereotactic frame which is securely attached to the skull of the patient. The stereoguide can be adjusted on the stereotactic frame in order to be positioned very accurately to direct a surgical instrument to the desired position. A guide wire may be used to rigidify tubular instruments inserted into the brain or guide tubular instruments, such as catheters for delivery of therapeutic agents or guide tubes which are inserted into the brain and through which other instruments may be passed.
A first aspect of the present invention provides a guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate part having a composition of at least 80% tungsten carbide.
Preferably the elongate part has a diameter of less than 1 mm.
More preferably the elongate part has a diameter of less than 0.6 mm. Even more preferably, the elongate part has a diameter of less than or equal to 0.4 mm.
The elongate part may include between 5-20% cobalt or nickel. More preferably, the elongate part includes about 5% cobalt or nickel.
The guide element may further comprise a coating surrounding the elongate part. The coating may comprise a different material than the elongate part. The coating may comprise a bio compatible material. The coating may comprise a plastics material. The coating may be one of polyimide, peek optima or technical polyurethane. Preferably the material of the coating is more resilient than the material of the guide element core.
Preferably the guide element is a guide wire or guide rod.
A second aspect of the present invention provides a guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate part comprising a material which fails rather than bends under force.
A third aspect of the present invention provides a guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate part comprising a non ductile material.
FIG. 5 shows a guidewire inserted into the brain using a stereoguide.
The guide tube 10 is shown in FIG. 1 and comprises a length of tube 12 with a hub 14 at one end. In this example it is made from a polyurethane plastic such as carbothane 55DB20. However, it may be made from any material which is biocompatible and sufficiently rigid at room temperature to maintain its central aperture. In this example, the tube 12 has an outer diameter of 0.6 mm and an inner diameter of 0.5 mm.
The guide tube is inserted into the brain through an aperture (e.g. burr hole) in the skull created by the surgeon. Once the length of tubing is inserted into the brain, the hub can be attached to the patient's skull, for example by bonding into a burr hole in the skull using an acrylic cement. A wire may be used to guide the guide tube into place, as disclosed in WO03/07784. Before, insertion, the guide tube is cut to a length short of the target. The distal end of the guide tube will typically fall several millimetres short of the target.
The inner tube 18 is illustrated in FIG. 2 and comprises two connected lengths of tubing, the distil tubing 20, which in this example has an outer diameter of 0.42 mm and an inner diameter of 0.2 mm and proximal tubing 22 which has a larger diameter. A stop element 24 links the proximal and distil tubing. The distal and proximal lengths of tubing are typically made of a polyurethane plastic, such as carbothane 85AB20, although other material could also be used. The stop element 24 is in this case also constructed using polyurethane plastic, such as carbothane 72DB20. Again other suitable materials may be used.
The stereoguide is used to first insert a guide element into the brain towards the target. The guide tube is inserted into the brain by threading it over the guide element using the secured stereoguide and fixed in place as described above. The guide element is then removed, leaving the guide tube in place. FIGS. 4A and 4B illustrate the assembled guide tube 10, inner tubing 18 and catheter 36. FIG. 4A is the assembly outside the skull and FIG. 4B is the assembly with the catheter inserted into the brain 42. FIG. 4B illustrates the hub 14 of the guide tube 10 fixed in place in a hole in the skull 44 by bone cement 46. The inner tube is inserted into the guide tube by inserting the distil tubing 20 into the guide tube 10 until the stop element 24 abuts the hub 14 of the guide tube. The stop element 24 thus acts as a stop to control the amount the length of the inner tubing which is inserted into the brain. The catheter 36 is inserted into the inner tube and is pushed through until its barb abuts the end of the proximal tubing 22 of the inner tubing.
WO03/077784 discloses a method of inserting fine instruments such as catheters and electrodes into the brain. A small diameter tungsten guidewire of 0.6 mm diameter is inserted into a fine tube and fixed within it, with the wire projecting from its end. The fine tube and wire are lowered together to the target in the brain using a stereoguide. The fine tube is then removed and the guide tube is threaded onto the wire and inserted into the brain. Once the guide tube is installed the guide wire is removed.
In practice, the guidewire may be inserted without the use of the fine tube.
FIG. 5 illustrates a guide wire 52 inserted into the brain using a stereoguide 50. The stereoguide is carried by a stereotactic frame (not shown) which is securely attached to the skull 54 of the patient. FIG. 5 shows a guide wire 52 inserted though guide elements 54,56 and clamps 58 of the stereoguide, through an aperture 60 in the skull 54 and into the brain. A guide tube 10 is shown threaded onto the guide wire, ready to be inserted into the brain. A stereoguide suitable for insertion of the guide wire into the brain is disclosed in WO03/077784.
For insertion of very fine catheters, a guide wire of very small diameter is required, for example 0.2 mm.
When the guide wire is inserted into the brain, it must penetrate the pia mater which is the delicate innermost layer of the meninges, the membranes surrounding the brain and spinal cord. The thin, mesh-like pia mater closely envelops the entire surface of the brain, running down into the fissures of the cortex. It joins with the ependyma which lines the ventricles to form choroid plexuses that produce cerebrospinal fluid.
Tungsten wire has the disadvantage that at these small diameters it can bend. This bending can cause the tip of the guide element to reach the wrong target in the brain, resulting in the subsequent guide tube and catheter being installed incorrectly.
In the present invention a guide element (e.g. a guide wire or guide rod) is made from a material, such as tungsten carbide, which is a stiff and brittle material.
Tungsten carbide has a different failure mode to tungsten. As tungsten is a non ductile material, it will fail rather than bend under force. This is unlike tungsten which will yield and deform under force. Thus a guide element (e.g. guide wire or guide element) made from a material which fails rather than bends under force and/or comprises a non ductile material, such as tungsten carbide, will not bend and the tip is inserted at the correct position.
The guide element comprises an elongate part, for example made of tungsten carbide. The tungsten carbide may include a percentage of other elements, for example cobalt. The addition of cobalt has the function of improving binding properties and is typically added in a range of 5-20% by weight. A suitable composition of the tungsten carbide guidewire is 95% WC and 5% Co, although other compositions may be used. An alternative additive is nickel, which also improves binding properties. Nickel also has the effect of increasing corrosion resistance and increasing biocompatibility. As before, nickel may be added in the range of 5-20% by weight.
An example of the dimensions of the tungsten carbide elongate part of the guide element is a diameter of 0.36 mm. The elongate part of the tungsten carbide guide element preferably has a diameter of less than 1 mm, although preferably a diameter of less than 0.6 mm and even more preferably a diameter of less than or equal to 0.4 mm.
When the guide element is inserted into the brain, it passes through the relatively tough pia mater (for approximately 5 mm) and then a much softer region of brain. Any breakage of the tungsten carbide will thus occur in the first 5 mm, during which the broken guide element can easily be removed.
The elongate part of the guide element may be coated with a material which will hold it together if it breaks. The coating comprises a biocompatible material which is more resilient than the tungsten carbide core.
It may comprise a biocompatible plastics material, for example polyimide, peek optima or technical polyurethane. A suitable coating could be applied by over moulding. The thickness of the coating is chosen to effectively hold broken pieces of the guide element together whilst limiting the increase in diameter of the guide element. The coating thickness will typically be in the range of 0.1 to 0.25 mm
The guide element may comprise, for example a guide wire or guide rod.
The guide element may be made from materials other than tungsten carbide which fail rather than bend under force and/or which are non ductile.
1. A guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate part having a composition of at least 80% tungsten carbide.
3. A guide element according to claim 2 wherein the elongate part has a diameter of less than 0.6 mm.
4. A guide element according to claim 3 where the elongate part has a diameter of less than or equal to 0.4 mm.
5. A guide element according to claim 1 wherein the elongate part includes between 5-20% cobalt or nickel.
6. A guide element according to claim 1 wherein the elongate part includes about 5% cobalt or nickel.
7. A guide element according to claim 1 wherein the guide element further comprises a coating surrounding the elongate part.
8. A guide element according to claim 7 wherein the coating comprises a different material than the elongate part.
9. A guide element according to claim 7 wherein the material of the coating is more resilient than the material of the elongate part.
10. A guide element according to claim 7 wherein the coating comprises a bio compatible material.
11. A guide element according to claim 7 wherein the coating comprises a plastics material.
12. A guide element according to claim 7 wherein the coating comprises a material from one of polyimide, peek optima or technical polyurethane.
13. A guide element according to claim 7 wherein the guide element is a guide wire or guide rod.
14. A guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate part comprising a material which fails rather than bends under force.
15. A guide element according to claim 14 wherein the guide element further comprises a coating surrounding the elongate part.
16. A guide element according to claim 15 wherein the coating is more resilient than the material of the elongate part.
17. A guide element according to claim 14 wherein the coating comprises a bio compatible material.
18. A guide element for insertion into the brain to guide implantable instruments, wherein the guide element comprises an elongate part, the elongate part comprising a non ductile material.
19. A guide element according to claim 18 wherein the guide element further comprises a coating surrounding the elongate part.
20. A guide element according to claim 19 wherein the coating is more resilient than the material of the elongate part.
21. A guide element according to claim 19 wherein the coating comprises a bio compatible material.
US12310207 2006-08-18 2007-08-20 Neurological apparatus Abandoned US20100217236A1 (en)
GB0616411A GB0616411D0 (en) 2006-08-18 2006-08-18 Neurosurgical instruments
PCT/GB2007/003169 WO2008020237A3 (en) 2006-08-18 2007-08-20 Neurological apparatus
US20100217236A1 true true US20100217236A1 (en) 2010-08-26
US12310207 Abandoned US20100217236A1 (en) 2006-08-18 2007-08-20 Neurological apparatus
US12310210 Active US9452241B2 (en) 2006-08-18 2007-08-20 Neurosurgical instruments
US13358019 Abandoned US20120123391A1 (en) 2006-08-18 2012-01-25 Neurological apparatus
US15235632 Pending US20160346505A1 (en) 2006-08-18 2016-08-12 Neurosurgical instruments
JP (3) JP5216770B2 (en)
EP (3) EP2601997B1 (en)
WO (2) WO2008020237A3 (en)
US20070000576A1 (en) * 2002-11-01 2007-01-04 Bernd Blanke Use of a non-corrosive, martensitically hardening steel
US20030045217A1 (en) * 1999-05-21 2003-03-06 Massa Ted R. Superhard material article of manufacture
EP2066364B1 (en) 2013-04-17 grant
ES2497967T3 (en) 2014-09-23 grant
CN101626802A (en) 2010-01-13 application
WO2008020241A2 (en) 2008-02-21 application
EP2056896A2 (en) 2009-05-13 application
US20160346505A1 (en) 2016-12-01 application
WO2008020237A3 (en) 2009-08-13 application
CN101626802B (en) 2013-07-03 grant
EP2601997A1 (en) 2013-06-12 application
JP2013150812A (en) 2013-08-08 application
JP5642823B2 (en) 2014-12-17 grant
JP5216770B2 (en) 2013-06-19 grant
CN101626801A (en) 2010-01-13 application
US20120123391A1 (en) 2012-05-17 application
WO2008020237A2 (en) 2008-02-21 application
CN103203064B (en) 2017-06-09 grant
EP2601997B1 (en) 2014-08-13 grant
US20090198218A1 (en) 2009-08-06 application
CN103203064A (en) 2013-07-17 application
JP2010501233A (en) 2010-01-21 application
JP2010501232A (en) 2010-01-21 application
GB0616411D0 (en) 2006-09-27 grant
US9452241B2 (en) 2016-09-27 grant
WO2008020241A3 (en) 2009-08-13 application
EP2066364A2 (en) 2009-06-10 application
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GILL, STEPHEN S.;STRATTON, MATHEW D. F.;DERRICK, HUGO G.;SIGNING DATES FROM 20070831 TO 20070904;REEL/FRAME:022286/0956