WO2008064397A1

WO2008064397A1 - A prosthesis delivery system

Info

Publication number: WO2008064397A1
Application number: PCT/AU2007/001601
Authority: WO
Inventors: Zoran Milijasevic; Ashish Diwan; Johnathon Choi; Ronald Ho
Original assignee: Columna Pty Ltd
Priority date: 2006-11-28
Filing date: 2007-10-22
Publication date: 2008-06-05

Abstract

A prosthesis delivery system (10) includes a plurality of nested tubes (12). An outermost tube (14) of the nested tubes (12) functions as a cannula in which the remaining tubes are received, the remaining tubes forming part of a prosthesis delivery apparatus (16). A wall portion of at least one of the tubes has a change in diameter (18) along its length to mate with a corresponding part (20) of a dispensing arrangement (24) for use with the prosthesis delivery apparatus (16).

Description

"A prosthesis delivery system"

Cross-Referenee to Related Applications

The present application claims priority from United States of America Provisional Patent Application No 60/867,574 filed on 28 November 2006, the contents of which are incorporated herein by reference.

Field

This invention relates, generally, to the delivery of a prosthesis to a site in a patient's body and, more particularly, to a prosthesis delivery system for the delivery of a prosthesis in a minimally invasive manner. While an embodiment has particular application in the delivery of a spinal disc nucleus prosthesis, the invention is not limited only to such an application.

Background

In the delivery of a prosthesis in a minimally invasive manner, use is made of a working cannula which is inserted through an incision in a patient's skin to the site to facilitate percutaneous delivery of the prosthesis to the site. A delivery mechanism is inserted into a lumen of the cannula for delivery of the prosthesis to the site. Generally, the cannula and the delivery mechanism are mounted on some form of structure such as a control device, a dispensing arrangement, or the like. In addition, the cannula and the delivery mechanism are made as thin as possible so that the incision is made as small as possible.

Because of the small diameter of the cannula and, hence, the large length to diameter ratio of the cannula, the system can be rather flimsy and unstable making it difficult for the clinician to steer a distal part of the cannula and the delivery system to the site. The weight of the structure to which the cannula and the delivery mechanism are attached exacerbates the problem.

Summary

According to a first aspect of the invention, there is provided a prosthesis delivery system which includes a plurality of nested tubes, an outermost tube of which functions as a cannula in which the remaining tubes are received, the remaining tubes forming part of a prosthesis delivery apparatus, a wall portion of at least one of the tubes having a change in diameter along its length to mate with a corresponding part of a dispensing arrangement for use with the prosthesis delivery apparatus. The prosthesis delivery apparatus may include a carrier tube which carries a component of the prosthesis on its distal end and a filler tube received in the carrier tube for charging a filler material into the component when the component is located at the desired location at a site in a patient's body. The prosthesis delivery apparatus may include a connector for connection to a withdrawal device to enable air to be withdrawn from the component during formation of the prosthesis in situ, the connector being arranged, in use, at a proximal end of the prosthesis delivery apparatus.

Further, the prosthesis delivery apparatus may include a displacement device for displacing the component of the prosthesis after it has been charged with the filler material. The displacement device may be a further tube mounted about the carrier tube.

In addition, the prosthesis delivery apparatus may include a cover tube to cover the component of the prosthesis, the cover tube fitting over the carrier tube. The cover tube may include a resiliently flexible distal portion to accommodate the component of the prosthesis.

Preferably, a wall portion of each of the tubes has a change in diameter along its length. The change in diameter along the length of each tube may be provided by a flared wall portion of each tube.

The system may include a manipulating arrangement carried at a proximal end of at least the cannula for effecting manipulation of the nested tubes. The manipulating arrangement of the cannula may include a rupturing mechanism for rupturing the cannula for removal. The rupturing mechanism may include a plurality of circumferentially spaced, longitudinally extending zones of weakness in a wall of the tube of the cannula and a gripping device arranged at a proximal end of the tube of the cannula. The gripping device may comprise a plurality of circumferentially spaced radially outwardly extending tabs which are pulled outwardly to cause rupturing of the zones of weakness of the cannula to facilitate withdrawal of the cannula after placement and setting of the prosthesis.

The system may include the dispensing mechanism, the dispensing mechanism including a tubular element having a distal end which corresponds with and mates with that part of the wall portion of the at least one tube having the change in diameter. The nested tubes may be configured to extend proximally of the distal end of the element to overlie the element. With this arrangement, the length of the unsupported ends of the tubes is considerably shortened thereby improving the rigidity of the tubes and the stability of the system. In addition, the balance of the system is improved rendering it easier for the clinician to control system. The dispensing mechanism may include a dispenser to which the element is attachable. The element may be a static mixer.

According to a second aspect of the invention, there is provided a prosthesis delivery system which includes a plurality of nested tubes, one tube being a carrier tube which carries at least a component of a prosthesis at its distal end and another tube constituting a delivery tube for delivering the nested tubes to a site at a patient's body; and a cover tube forming part of the nested tubes, the cover tube being arranged outwardly of the carrier tube to cover the component when the carrier tube is inserted into the delivery tube to protect the component.

The cover tube may have a length approximating a length of the delivery tube with the carrier tube being dimensioned so that the component protrudes beyond a distal end of the delivery tube in an uncovered condition.

The system may include a displacement device arranged outwardly of the carrier tube with the cover tube being arranged outwardly of the displacement device. The displacement device may be a further tube mounted about the carrier tube.

The cover tube may have a resiliency flexible distal end to accommodate the component of the prosthesis. The resilient flexibility of the distal end of the cover tube may be effected by slotting the distal end to provide a plurality of leaves able to flex radially outwardly.

Brief Description of Drawings

Fig. 1 shows a sectional side view of a prosthesis delivery system in accordance with an embodiment of the invention; Fig. 2 shows, on an enlarged scale, a sectional side view of the encircled portion of the system marked 'A' in Fig. 1 of the drawings;

Fig 3 shows a component of a prosthesis delivery system in accordance with another embodiment of the invention;

Fig 4 shows a sectional side view of a part a prosthesis delivery system including the component of Fig. 3; and

Fig 5 shows a sectional side view of a part of a further embodiment of a prosthesis delivery system including the component of Fig 3.

Detailed Description of Exemplary Embodiment Referring initially to Figs 1 and 2 of the drawings, reference numeral 10 generally designates an embodiment of a prosthesis delivery system. The prosthesis delivery system 10 includes a plurality of nested tubes 12 shown in greater detail in Fig. 2 of the drawings. An outermost tube 14 of the nested tubes 12 functions as a cannula in which the remaining tubes are received. The remaining tubes form part of a prosthesis delivery apparatus 16. The tubes of the nested tubes 12 have a flared wall portion 18. The flared wall portion 18 of the nested tubes mates 12 with a tapered end 20 of a static mixer 22 of a dispensing arrangement 24 of the apparatus 16 of the system 10.

The cannula 14 further includes a manipulating arrangement 26, arranged at a proximal end of the cannula 14, for connecting and effecting manipulation of the nested tubes 12.

As indicated above, a first tube 14 of the nested tubes is the cannula which is used for insertion of the prosthesis delivery apparatus 16 percutaneously to a site in which a prosthesis is to be inserted.

The system 10 is intended particularly for use in the insertion of an intervertebral disc nucleus prosthesis in position in a disc after performance of a nucleotomy, if necessary, on a disc to remove the natural nucleus of the disc. The nucleus may have herniated through an annulus of the disc due to degeneration of the disc. In such circumstance, it may not be necessary to perform a nucleotomy on the disc. The prosthesis includes an envelope 28. The envelope 28 is carried on the end of a carrier tube 30. The envelope 28 is an expansible envelope of an elastically deformable material which is charged with a filler material to fill a cavity of the disc left by removal of the natural nucleus. Typically, the envelope is of a silicone material which is capable of expanding up to 1000% its relaxed state without plastically deforming. The filler material used with the envelope 28 is also of a silicone material and is dispensed from a dispenser 32 of the dispensing arrangement 24. The filler material is charged into the envelope 28, in use, through a filler tube 34. The filler tube 34 is nested within the carrier tube 30. The prosthesis is described in greater detail in applicant's International Patent Application No. PCT/AU2006/001176 entitled "A tissue prosthesis and a method of, and equipment for, forming a tissue prosthesis" filed on 15 August 2006, The International Patent Application is incorporated by reference in this specification in its entirety.

A further tube 36 is arranged outwardly of the carrier tube 30 and is used to push off the envelope 28 from the carrier tube 30 after being filled with the filler material and the filler material has at least partially set or cured. It will be noted that each of the tubes 14, 30, 34 and 36 has the flared portion 18 so that all the tubes mate with the tapered end 20 of the static mixer 22 of the dispensing arrangement 24. Further, a proximal portion of the nested tubes 12 projects proximally of the tapered end 20 of the static mixer 22 to surround the static mixer 22 as shown in greater detail in Fig. 1 of the drawings. The tubes 14, 30, 34 and 36 are locked together once nested. Further, the tubes 30 and 34 seal hermetically once nested and locked together.

The manipulating arrangement 26 of the cannula 14 includes a rupturing mechanism for rupturing the cannula after placement of a distal end of the prosthesis delivery apparatus 16. The rupturing arrangement comprises a pair of opposed longitudinally extending lines of weakness, one of which is shown at 38 in Fig. 2 of the drawings. The other line of weakness is diametrically opposed to the shown line of weakness 38. The lines of weakness 38 divide the cannula into two shells 40 and 42. The manipulating arrangement 26 comprises a pair of opposed tabs 44. Each tab 44 is integrally formed with one of the shells 40, 42 of the cannula 14. The tabs 44 are used for connecting the nested tubes 12 to the cannula 14. Also, by pulling radially on the tabs 44, the cannula 14 ruptures along the lines of weakness 38 facilitating withdrawal of the cannula 14 from the prosthesis delivery apparatus 16.

A gap 46 (Fig. 2) is defined between the carrier tube 30 and the filler tube 34. The gap 46 communicates with a port 48 (Fig. 1) and with the interior of the envelope 28. The port 48, in use, forms part of a boss 50 and an evacuation apparatus (not shown) is connected to the port 48 to enable the interior of the envelope 28 to be evacuated either prior to or as the filler material is charged into the envelope 28.

The silicone used for expanding the envelope 28 is of the type which, prior to use, is maintained in two separate parts. Thus, the dispenser 32 has two compartments 52, in each of which one part of the silicone material is stored, prior to being fed through the static mixer 22, where mixing of the parts takes place, and being charged into the envelope 28.

In use, an incision is formed in the skin of the patient. The cannula 14, with a trocar (not shown) contained in a lumen of the cannula 14, is inserted through the incision to the disc on which the operation is to be performed. The trocar is used to perform an annulotomy on an annulus of the disc. Once that operation has been completed, the trocar is withdrawn. A device (not shown) is inserted through the cannula 14 to perform the nucleotomy, if necessary. The device could, for example, be a mechanical device such as a reamer to ream the degenerative nuclear material from the intervertebral disc. After completion of the nucleotomy, the device is withdrawn. The prosthesis delivery apparatus 16 is then inserted into the lumen of the cannula 14 and the envelope 28 is inserted through the annulotomy aperture into the cavity of the disc formed as a result of the nucleotomy. The filler material is dispensed from the dispenser 32, through the static mixer 22 and the filler tube 34 into the interior of the envelope 28 while, simultaneously, a suction is maintained on the port 48 and the gap 46.

In an embodiment, the cannula 14 is then removed by rupturing it along the lines of weakness 38 by pulling radially outwardly on the tabs 44.

Once this has occurred, the push off tube 36 is free to be manipulated relative to the carrier tube 30 by being urged in a direction of arrow 54 (Fig. 2) by means of a manipulating ring 56 carried at a proximal end of the push off tube 36. Pushing off the envelope 28 from the carrier tube 30 allows the prosthesis delivery apparatus 16 to be withdrawn from the patient's body.

In another embodiment, the cannula 14 remains in place. The envelope 28 is pushed off from the carrier tube 30 by withdrawing the carrier tube 30 relative to the push off tube 36 in a direction opposite to the arrow 54. The cannula 14 is the final item to be removed with the remaining nested tubes 12 still contained in and attached to the cannula 14.

Referring now to Figs. 3-5 of the drawings, a further embodiment of a prosthesis delivery system 10 is illustrated. With reference to the previous drawings, like reference numerals refer to like parts, unless otherwise specified.

In this embodiment, the system 10 includes a further component in the form of a cover tube 60 (Fig. 3). The cover tube 60 constitutes a protective sheath and, at least initially, protects the envelope 28 of the prosthesis when it is inserted into the cannula 14.

For this purpose, a distal end of the cover tube 60 is slotted, as shown by slots 62. In this embodiment, two slots 62 are provided to define a pair of opposed resiliently flexible leaves 64. The leaves 64 are able to be displaced outwardly in the direction of arrows 66. Thus, in use, the cover tube 60, which has substantially the same length as the cannula 14, is placed over the prosthesis delivery apparatus 16 so that the envelope 28 is received between the leaves 66 at the distal end of the cover tube 60. The entire prosthesis delivery apparatus 16, including the cover tube 60, is then inserted into the cannula 14 and the distal end of the cover tube 60 protects the envelope 28. The cover tube 60 is arranged between the cannula 14 and the push-off tube 36. It will, however, be appreciated that, if the cover tube 60 is appropriately dimensioned, it can, itself, act as the push-off tube , the push-off tube 36 then being omitted.

A proximal end of the cover tube 60 carries connectors 68. These connectors 68 engage with the tabs 44 of the cannula 14 so that the cover tube 60 engages with and connects to the cannula 14 to enable the remaining tubes of the nested tubes 12 to move towards a distal end of the tubes 12 so that the envelope 28 can protrude beyond the end of the cover tube 60 and the distal end of the cannula 14 as shown in Fig. 1 of the drawings. The tabs 44, in turn, engage with the manipulating ring 56 to retain the cannula 14 in position relative to the prosthesis delivery apparatus 16.

In the embodiment shown in Fig. 4 of the drawings, the cover tube 60 has a flared portion 18 to nest with the remaining tubes 12 of the prosthesis delivery system 10.

In Fig. 5 of the drawings, a set of nested tubes 12 is provided which does not have the flared portion 18 and is mountable to a distal end of the static mixer 22.

It is an advantage of this embodiment that the cover tube 60 obviates the need for lubricants to enable the envelope 28 to be inserted into a lumen of the cannula 14. The cover tube 60 serves to protect the envelope 28 as the prosthesis delivery apparatus 16 is inserted into the cannula 14. It will be appreciated that, in use, the incision is of such a size that at least part of the static mixer 22 can be inserted through the incision. Due to the flared portion 18 of the nested tubes 12, the overall length of the prosthesis delivery apparatus 16 and the system 10 itself is significantly shorter than would otherwise be the case. Because of this, the entire system 10 has improved stability and balance. This stability allows the clinician a higher degree of control in manoeuvring the system 10 both to the site at which the prosthesis is to be delivered as well as while forming the prosthesis at the site.

This is enhanced due to the fact that the nesting of the tubes 12 about the static mixer 22 also improves the rigidity of the entire system 10 resulting in less free movement of a distal end of the prosthesis delivery apparatus 16 of the system 10. This further enhances the clinician's control over the system 10.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A prosthesis delivery system which includes a plurality of nested tubes, an outermost tube of which functions as a cannula in which the remaining tubes are received, the remaining tubes forming part of a prosthesis delivery apparatus, a wall portion of at least one of the tubes having a change in diameter along its length to mate with a corresponding part of a dispensing arrangement for use with the prosthesis delivery apparatus.

2. The system of claim 1 in which the prosthesis delivery apparatus includes a carrier tube which carries a component of the prosthesis on its distal end and a filler tube received in the carrier tube for charging a filler material into the component when the component is located at the desired location at a site in a patient's body.

3. The system of claim 2 in which the prosthesis delivery apparatus includes a connector for connection to a withdrawal device to enable air to be withdrawn from the component during formation of the prosthesis in situ.

4. The system of claim 2 or claim 3 in which the prosthesis delivery apparatus includes a displacement device for displacing the component of the prosthesis after it has been charged with the filler material.

5. The system of claim 4 in which the displacement device is a further tube mounted about the carrier tube.

6. The system of any one of claims 2 to 5 in which the prosthesis delivery apparatus includes a cover tube to cover the component of the prosthesis, the cover tube fitting over the carrier tube.

7. The system of claim 6 in which the cover tube includes a resiliently flexible distal portion to accommodate the component of the prosthesis.

8. The system of any one of the preceding claims in which a wall portion of each of the tubes has a change in diameter along its length.

9. The system of any one of the preceding claims in which the change in diameter along the length of the at least one tube is provided by a flared wall portion of the at least one tube.

10. The system of any one of the preceding claims which includes a manipulating arrangement carried at a proximal end of at least the cannula for effecting manipulation of the nested tubes.

11. The system of claim 10 in which the manipulating arrangement of the cannula includes a rupturing mechanism for rupturing the cannula for removal.

12. The system of claim 11 in which the rupturing mechanism includes a plurality of circumferentially spaced, longitudinally extending zones of weakness in a wall of the tube of the cannula and a gripping device arranged at a proximal end of the tube of the cannula.

13. The system of any one of the preceding claims which includes the dispensing mechanism, the dispensing mechanism including a tubular element having a distal end which corresponds with and mates with that part of the wall portion of the at least one tube having the change in diameter.

14. The system of claim 13 in which the nested tubes are configured to extend proximally of the distal end of the element to overlie the element.

15. The system of claim 13 or claim 14 in which the dispensing mechanism includes a dispenser to which the element is attachable.

16. The system of any one of claims 12 to 15 in which the element is a static mixer.

17. A prosthesis delivery system which includes a plurality of nested tubes, one tube being a carrier tube which carries at least a component of a prosthesis at its distal end and another tube constituting a delivery tube for delivering the nested tubes to a site at a patient's body; and a cover tube forming part of the nested tubes, the cover tube being arranged outwardly of the carrier tube to cover the component when the carrier tube is inserted into the delivery tube to protect the component.

18. The system of claim 17 in which the cover tube has a length approximating a length of the delivery tube with the carrier tube being dimensioned so that the component protrudes beyond a distal end of the delivery tube in an uncovered condition.

19. The system of claim 17 or claim 18 which includes a displacement device arranged outwardly of the carrier tube with the cover tube being arranged outwardly of the displacement device.

20. The system of claim 19 in which the displacement device is a further tube mounted about the carrier tube.

21. The system of any one of claims 17 to 20 in which the cover tube has a resiliently flexible distal end to accommodate the component of the prosthesis.

22. The system of claim 21 in which the resilient flexibility of the distal end of the cover tube is effected by slotting the distal end to provide a plurality of leaves able to flex radially outwardly.