WO1993024058A1

WO1993024058A1 - Electrode insertion tool

Info

Publication number: WO1993024058A1
Application number: PCT/AU1993/000242
Authority: WO
Inventors: Janusz Kuzma
Original assignee: Cochlear Pty. Limited
Priority date: 1992-05-29
Filing date: 1993-05-26
Publication date: 1993-12-09

Abstract

A tool (20) is described for handling small objects for surgical implantation, for example electrode arrays (30) for intra-cochlear implants (31). The tool (20) grips the object by suction for handling via a source of suction (40) and once it is in place, suction is removed and the object is released.

Description

Electrode Insertion Tool Technical Field

The present invention relates to an insertion tool for a body implantable lead or similar device such as an electrode array for a cochlear implant. Background Art

A typical intra-cochlear electrode assembly, for example, includes an electrode array for insertion into the cochlea of a patient, the array being formed largely from silicone material with electrodes on the surface. As the diameter of the array is less than 1 mm, it will be appreciated that the insertion of these small flexible electrode arrays into specific regions of the human body such as the scala tympani is a delicate task for a surgeon. To perform the insertion without causing damage to the fragile structure of the electrodes and lead wires of the electrode arr?y, and without irreversibly damaging the auditory nerve fibres of the inner ear, requires the development of special insertion tools and the training of surgeons in their proper use.

Until now the tools used for insertion of cochlear implants have nc+ πroved entirely satisfactory, and in particular damage to the delicate electrc . . array assembly may occur.

Some tools developed are used to direct and force the electrode into the cochlear canal. This method of insertion is not entirely effective and can cause damage to the electrode structure. In addition, there is a tendency for surgeons to also use miniature crocodile forceps or tweezers to aid with the insertion. This method also tends to cause damage to the electrode structure.

Another type of insertion tool for cochlear electrodes has been developed to insert curved electrodes. In this case the curved electrode is initially straightened as it is loaded into an introducer tube. This tube is then positioned to allow the electrode to be pushed into the cochlear canal by a mechanical ejection method. This insertion technique does not give a desirable level of control over the insertion to allow the surgeon to feel for obstructions which can damage the electrode.

It is an object of the present invention to overcome at least some of the aforementioned disadvantages of existing insertion tools. Summary of Invention

In one aspect, the present invention provides an insertion tool for an item to be surgically implanted, said tool having a body comprising means to releasably engage by suction at least part of the item. In another aspect, the present invention provides a tip for an insertion tool for an item to be surgically implanted, said tip comprising means to releasably engage by suction at least part of the item.

In a further aspect, the present invention provides an insertion tool for a body implantable device, said tool having a tip comprising means to releasably engage by suction at least part of the device.

Preferably, the means to releasably engage is shaped so as to at least partly receive the item to be implanted.

The insertion tool and tip of the invention are suitably adapted for releasably engaging an electrode array for a cochlear electrode assembly. In another aspect, the present invention provides, in combination an intra- cochlear electrode assembly comprising at least one electrode array for insertion into the cochlea, and an insertion tool for inserting one end of a said array into the cochlea, said tool having a body comprising means to releasably engage by suction at least part of the array.

In a further aspect, the present invention provides, in combination, an intra- cochlear electrode assembly comprising at least one electrode array for insertion into the cochlea, and a tip for an insertion tool for inserting an end of the array into the cochlear, said tip comprising means to releasably engage by suction at least part of the array.

In another aspect the present invention provides a method of implanting an item in the body of a patient, comprising, providing an insertion tool having engaging means to releasably engage by suction at least part of the item, providing a source of suction for the insertion tool, engaging said engaging means with said at least part of the item by suction, implanting the item into the body, removing the suction from the insertion tool, thereby releasing the item from the tool, and withdrawing the tool from the body.

The tool of the present invention has the advantage that it is very gentle with the body implantable device such as an electrode array, and its use gives the surgeon both the necessary full control over the force used to direct for example an electrode into the cochlea, and full control in handling during initial manipulation of the electrode.

The tool of the present invention is suitably powered from a central vacuum installation or vacuum pump commonly used in operating theatres.

The tip and tool of the present invention are conveniently made from a bio- compatible material such as a hard plastic material, or from an autoclavable material such as stainless steel, or from any other suitable material.

The engaging surface of the tip is suitably sized and shaped so as to be compatible with the surface of the body implantable device such as an electrode array. In one preferred embodiment, the tip includes a groove for engaging at least part of the device. The inventive tip of the present invention conveniently includes an aperture connectable to a source of suction. The tip is connectable by any means to the insertion tool, and may suitably be integral therewith in a single piece moulded construction. Brief Description of Drawings The invention will now be described in more detail with reference to a preferred embodiment illust'~ⁱed in the accompanying drawings in which:-

Figure 1 is a perspective view of a tip for an insertion tool in accordance with one aspect of the present invention;

Figure 2 is an end section of the tip of Figure 1 ; Figure 3 is a top elevation of a tool according to the present invention including the tip of Figures 1 and 2;

Figure 4 is a sectional side elevation of the tool of Figure 3; Figure 5 is a close-up of the tip of the present invention engaging an electrode array; and

Figure 6 illustrates the preferred method of using the insertion tool with the electrode array. Detailed Description

With reference to the drawings, Figure 1 shows generally a tip 10 for an insertion tool for implanting an lead type device, such as an intra-cochlear electrode array assembly, into a body cavity. Tip 10 includes a generally cylindrical body 11 having a groove formed along at least a part of its length, defined by ridges 13 and 14, to receive and releasably engage at least part of an electrode array. The groove 12 is configured to complement the size and shape of the electrode array, and in the preferred embodiment is substantially U- or C- shaped as shown. Groove 12 terminates at point 16 in the form of a barb.

The tip 10 also includes an aperture 15 of substantially cylindrical configuration which is suitably attached to a handle portion and in turn to a source of suction such as a central vacuum installation or operating theatre vacuum pump (not shown). Any suitable conventional suction source may be used.

Tip 10 includes a cavity 17 intermediate the groove 12 and aperture 15 ensuring groove 12 and aperture 15 are in fluid communication so that suction may be applied in the region of the groove 12 as required.

Figures 3 and 4 illustrate a preferred insertion tool 20 including the tip 10 of Figures 1 and 2. Insertion tool 20 has a longitudinal axis 21 and comprises tip 10 at one end thereof. The tool includes an intermediate tubular member 22 of circular cross section defining a bore 25 therein. The intermediate tubular member 22 tapers at 23 to a tubular member 24 of larger diameter than the intermediate tubular member 22. Member 24 is also conveniently of circular cross section defining a bore 26 therein. Member 24 defines a handle portion for gripping by a surgeon. As shown the tip 10 may be integral with the tool 20 and can thus be formed as a one piece moulded construction, preferably of bio-compatible material. Preferably, tip 10 is formed from a plastic material and is intended to be disposable - tool 20 may be reused if desired. Alternatively, the tip 10 and tool 20 may be formed from material can be sterilised and reused, such as stainless steel.

It will be noted from Figure 4 that the longitudinal axis 27 of tip 10 is not co- axial with the longitudinal axis 21 of the insertion tool 20. This construction is intended to provide sufficient angular displacement of the electrode array from the body of the insertion tool to allow it to be conveniently utilised by the surgeon. The axial displacement of the tip 10 with respect to the insertion tool 20 may be typically of the order of 0 to 20 degrees, preferably 5 to 15 degrees and more preferably approximately 10 degrees.

Figures 5 and 6 show tip 10 engaging an electrode array 30. Electrode array 30 may form part of a cochlear electrode assembly 31. A source of suction 40 is attached to one end of the insertion tool 20 enabling the tip 10 to releasably engage by suction at least a part of the electrode array 30. In use, the surgeon takes the insertion tool 20 in one hand, and an electrode assembly such as a intra-cochlear electrode assembly 31 having an array 30 in the other hand.

The surgeon, with the aid of a microscope, simply lines up the electrode array 30 with the tip 10 and applies suction to the tool 20 and hence the tip 10. The array 30 is readily drawn into and engages the groove 12 of tip 10. The surgeon subsequently inserts the array into the body of the patient such as the cochlear canal. The need for a secondary gripping tool such as a pair of forceps or tweezers is obviated since the application of suction permits full control of the electrode array 30 to be accomplished. Once the electrode array is in place, the suction to the insertion tool 20 is switched off thereby releasing the electrode array 30 from tip 10. Removal of the insertion tool 20 from the body cavity is then facilitated.

The suction may be controlled by any existing arrangement which is found convenient, or if desired a valve arrangement of some type may be provided within tool 20.

Industrial Applicability

It will be appreciated by surgeons that while the invention is described with reference to implantation of an intra-cochlear electrode array, the invention has application in other surgical applications where similar problems may arise.

It will be apparent from the foregoing that the present invention provides a novel and effective solution to the inherent problems of existing insertion tools for electrode arrays. It will be appreciated that variations and additions may be made to the present invention without departing from the scope thereof.

Claims

1 . An insertion tool for an item to be surgically implanted, said tool having a body comprising means to releasably engage by suction at least part of the item.

2. A tool according to claim 1 , wherein the item is an intracochlear electrode.

3. A tool according to claim 1 or claim 2 , wherein the means to releasably engage is shaped so as to at least partly receive the item to be implanted.

4. A tip for an insertion tool for an item to be surgically implanted, said tip comprising means to releasably engage by suction at least part of the device.

5. A tool according to claim 4, wherein the item is an intracochlear electrode.

6. A tool according to claim 4 or claim 5, wherein the means to releasably engage is shaped so as to at least partly receive the item to be implanted.

7. An insertion tool for an item to be surgically implanted, said tool having a tip comprising means to releasably engage by suction at least part of the item.

8. A tool according to claim 7, wherein the item is an intracochlear electrode.

9. A tool according to claim 7, wherein the means to releasably engage is shaped so as to at least partly receive the item to be implanted.

10. In combination, a cochlear electrode assembly comprising at least one electrode array for insertion into a cochlea, and an insertion tool for inserting one end of a said array into a cochlea, said tool having a body comprising means to releasably engage by suction at least part of said array.

1 1. In combination, an intra-cochlear electrode assembly comprising at least one electrode array for insertion into the cochlear, and a tip for an insertion tool for inserting an end of a said array into the cochlear, said tip comprising means to releasably engage by suction at least part of said array.

1 2. A method of implanting an item in the body of a patient comprising, providing an insertion tool having engaging means to releasably engage by suction at least part of the item, providing a source of suction for the tool, engaging said engaging means with said at least part of the item by suction, implanting the item into the body, removing the suction from the insertion tool, thereby releasing the item from the tool, and withdrawing the tool from the body.