WO2005068014A1

WO2005068014A1 - Neurological tool

Info

Publication number: WO2005068014A1
Application number: PCT/EP2005/000275
Authority: WO
Inventors: Heinrich Gerding; Thomas Diessner; Dietmar LÜTKE NOTARP; Hans Christian LÜDTKE-HANDJERY; Ralf Hornig; Stefan Hosdorf; Valerij Ortmann
Original assignee: Iip-Technologies Gmbh
Priority date: 2004-01-15
Filing date: 2005-01-13
Publication date: 2005-07-28
Also published as: DE102004002379A1

Abstract

The invention relates to a device for the minimally invasive implantation of diagnostic or therapeutic aids. Said device comprises a housing for fixation and for connection to secondary units. The aid in foil form is situated in a cannula and the device is equipped with a sliding mechanism, which is used to propel the aid step-by-step out of the cannula and to re-introduce said aid into the latter.

Description

Neurological tool

The present invention relates to a minimally invasive neurological tool for diagnosis and therapy. More specifically, the present invention relates to an electrical diagnostic and therapeutic tool for the human or animal retina, optic nerve and visual cortex.

The light-sensitive tissue that covers the back of the eye and that contains the light-sensitive photoreceptor cells is called the retina. The retina consists of two types of photoreceptors, the rod and the cone, as well as several layers of other non-light-sensitive nerve cells. The rods and cones convert light into electrical impulses that are processed by other nerve cells. The ganglion cells generate the output signal of the retina. The optic nerve transmits the visual information to the brain, where it is converted into a sensory "seeing".

Various diseases such as macular degeneration or retinitis pigmentosa cause degeneration of the photoreceptor cells. Degeneration often affects other cells of the retina, but it is known that even after years of blindness, the ganglion cells are essentially intact.

Numerous attempts have been made in recent years to develop devices that can assist in relieving or curing retinal blindness. Various methods of restoring eyesight have been proposed.

One method involves the implantation of a photosensitive device to stimulate the neurons or ganglion cells. For example, in European application EP0460320A2 a visual prosthesis was proposed which has a tightly packed array of small solar cells, which in turn are coupled to a large number of electrodes which are intended to stimulate neurons on the surface of the retina in a pattern corresponding to the illumination. Another approach is shown in US Pat. No. 5,935,155, in which the received electromagnetic energy of a small induction coil is converted into electrical stimulation pulses. A compact array of electrodes, which is in contact with the ganglion cells, induces the visual sensation through a stimulation pattern. Both approaches are still in the development stage and require a number of human and animal tests to evaluate each technology.

The evaluation comprises a series of implantations of the electrode arrangements in a human or animal eye. For this purpose, the electrodes are brought into direct contact with the retina and transmit electrical pulses to the ganglion cells.

Humayun describes two different electrodes in Vision Research 39 (1999) 2569-2576 and in Aren. Ophalmol. / Vol. 114, Jan. 1996, pp.40-46. Both electrode arrays are brought close to the retina without any mechanical contact to manufacture the ganglion cells. The mechanical rigidity and the sharp edges pose a high risk of mechanical damage to the retina. The several millimeter wide opening required for the implantation of such electrodes increases the risk of infection when carrying out the test.

Eckmiller describes in Invest. Ophthalmol. Vis. Be. 2002 43: E-Abstract 2848 the implantation of a thin micro contact tape and the epiretinal stimulation with the help of this tape. The special elasticity of this film-like micro contact tape allows a safe implantation of the electrode structure and direct contact with the retina.

A safe and effective evaluation method is still in development. The same method will be used later to diagnose the retinal degeneration process before a stimulation device is permanently implanted.

It is therefore an object of the present invention to provide a device for the minimally invasive, short-term implantation of diagnostic or therapeutic aids, with which a diagnostic aid in film-like form can be safely introduced into the tissue in question.

This object is achieved by a device with the features of claim 1.

Further advantageous refinements of the invention result from the dependent patent claims.

An exemplary embodiment of the invention is described below with reference to the drawing. Show it:

1: a device according to the invention when used in the eye of a mammal; 2: a schematic representation of the device in a perspective representation;

3: the device according to FIG. 2 in a cross section from the side; such as

4 shows a cross section through the cannula of the device with the aid located therein.

1 shows a device according to the invention during the implantation of an electrically conductive contact film 10 into the eye of a mammal. An inner cannula 1 penetrates the sclera of the eye and is brought close to the retina. The contact film 10 can then be pushed out of the inner cannula 1 and thus come into electrical contact with the retina. For removal, the contact film 10 can be drawn back into the inner cannula 1 and the implantation device can then be removed from the eye again. The entire process can be visually observed by the user through the lens of the affected eye.

Figure 2 shows the details of the device used in Figure 1 in a perspective exploded view. The device has a base body 6. Which essentially represents the handpiece of the device. In the base body 6, a slide consisting of lower slide part 2 and upper slide part 3 is slidably mounted in the longitudinal direction. The space in which the slide is arranged is closed by a cover 4.

The lower part 2 of the slide carries an outer cannula 7 on its front side, which in the assembled state overlaps an inner cannula 1. The inner cannula 1 is arranged on a closure piece 13 which closes the base body 6 on the end face.

A micro contact foil 10 is fixed in the slide. The micro-contact foil 10 is guided from the slide through the outer cannula 7 and the inner cannula 1. A seal 5 closes the outer space connected to the outer cannula 7 from the inner space of the slide and in particular from a connecting device 8 which is provided for external contacting of the micro-contact foil 10. With a supply unit 9, an electrical contact of the micro-contact foil is made via the connection device 8 to external devices, without this significantly restricting the handling of the hand-held device.

The lid 4 is secured on the base body 6 with a locking ring 11 c. The lower slide part 2 and the upper slide part 3 are fixed to each other by a further locking ring 11 a. The closure piece 13, which carries the inner cannula 1, is secured to the handheld device with a locking ring 11b.

FIG. 3 shows the handheld device in a cross section from the side.

The lower slide part 2 and the upper slide part 3 are assembled in Figure 3 and secured with the locking ring 11 a. The connection device 8 is connected to the connection area of the microcontact film 10 by means of a connecting piece 14. The micro-contact foil is firmly and immovably in the lower part 2 of the slide. The seal 5 is pressed against the bottom part 2 of the slide by a screw 15 and presses the micro-contact foil against the bottom part 2, so that the micro-contact foil is fixed here and at the same time sealed off in a liquid-tight manner. From there, the micro-contact film enters the outer cannula 7 to the left, which is larger in its outer dimensions than the inner cannula 1 and which surrounds it from the outside in an overlap area. The micro-contact foil 10 merges from the outer cannula 7 into the inner cannula 1 and, in the illustration in FIG. 3, lies essentially completely in the inner cannula 1. The base body 6 is closed by the cover 4 above the slide arrangement, so that overall there is an approximately pin-shaped, manually manageable hand-held device.

Finally, FIG. 4 shows the inner cannula 1 in a cross section. It is illustrated that the inner cannula 1 has an approximately rectangular cross section with such a free inner lumen. The microcontact film 10 is located in this lumen. The inner cannula 1 is provided on the inside with a coating 12 which protects the microcontact film 10 from adhesion to the inner cannula 1, so that it is easier to move it into the position shown in FIG. The coating 12 is preferably a silicate coating which does not lose its insulating and friction-reducing properties even under the influence of body fluids.

The device described so far has been designed for the diagnostic and therapeutic electrical stimulation of the retina of mammals and humans. The tool can also be used for other types of minimally invasive neurological diagnostic and therapeutic aids. The advantage of the proposed construction lies in the ability to implant a thin and very flexible micro-contact foil 10 as an aid through different tissue layers and to bring it precisely to the desired location at the tip with the affected tissue. This effect is achieved in that the aid is stored in the correspondingly shaped inner cannula 1 and is protected during the implantation process. The inner cannula provides mechanical protection for the device during implantation.

Since in the application shown in the eye there is an internal pressure that is higher than the external pressure, it is proposed to provide pressure relief openings 16 in the closure piece 13, as a result of which the pressurized liquid can escape from the eye through the inner cannula 1. A not shown Outlet opening can also occur on the section of the inner cannula 1 located outside the eye.

The base body 6 serves as a support base for the other components of the device described so far. The base body 6 can be made of a polymer or another suitable, preferably electrically non-conductive material with sufficient rigidity. The material should be sterilizable and biocompatible for short-term contact with blood vessels and tissue. The outer cannula 7, which surrounds the micro-contact foil 10, serves as a kind of mechanical protective element between the slide and the inner cannula 1, in order to prevent the micro-contact foil 10 from bulging under pressure. The arrangement of the inner and outer cannula can also be reversed, so that the inner cannula 1 in the present case is connected to the slide and thus displaceable and the outer cannula 7 in the present case is firmly connected to the closure piece 13 and cannot be displaced.

As described above, the seal 5 fixes the aid, in the present case the micro-contact film 10, on the lower slide part 2. In addition, the micro-contact film 10 can also be glued to the lower slide part 2. The supply device 9 ensures the connection of the microcontact film 10 to an external signal generator and, if appropriate, a corresponding detector.

The auxiliary means in the form of the micro-contact film 10 as well as the connection device 8, the lower slide part 2, the upper slide part and the outer cannula 7 represent a slide mechanism which can be moved within the hand-held device by, for example, 15 mm in the longitudinal direction of the base body 6. The locking ring 11 a serves to secure the slide mechanism itself.

When used in the eye according to FIG. 1, it is possible in this way that the free end of the micro-contact film 10 with a micro-contact array after the implantation of the inner capacitor cannula in the eye is expelled by moving the slide mechanism 2, 3, 7 towards the inner cannula 1 from the inner cannula 1 and can be connected to the nerve tissue to be examined or stimulated.

In this way, it is possible for the first time to test the functionality of the ganglion cells and the optic nerve in a patient suffering from retinitis pigmentosa or macular degeneration with a short-term electrical stimulation device, the micro-contact foil 10, in order to make a decision based on this test can determine whether and in what form a visual prosthesis based on electrical stimulation of the nerve cells is suitable for the patient concerned.

Other applications of the device described are also possible. This device will therefore always be usable when a thin, flexible and mechanically sensitive aid has to be connected to an equally sensitive tissue. The special design ensures that the aid is not damaged during the implantation and that the cannula 1, which is necessarily relatively rigid for the implantation, does not have to come into contact with the tissue to be treated or examined.

The small dimensions of the inner cannula 1 and the micro-contact foil 10, which can be less than 2 mm wide and less than 1 mm thick (in the illustration in FIG. 4), guarantee minimally invasive implantation.

Claims

Patent claim

1. A device for minimally invasive implantation of diagnostic or therapeutic aids, with a housing serving for holding and connecting to auxiliary units, characterized in that the aid is arranged in a film-like form in a cannula and that a sliding device is provided with which the aid can be moved in sections out of the cannula and back into the cannula.

2. Device according to claim 1, because of the fact that it is a hand-held device or a device guided by a technical holding system.

3. Device according to one of the preceding claims, d a d u r c h g ek e n n z e i c h n e t that the sliding mechanism for exposing the aid can be operated manually or by means of an electromechanical or hydraulic or pneumatic drive.

4. Device according to one of the preceding claims, d a d u r c h g e k e nn z e i c h n e t that the sliding mechanism can be actuated with a finger of the hand holding the device.

5. Device according to one of the preceding claims, since you rchgeke nn zeic hn et that the sliding mechanism can be activated with a foot switch.

6. Device according to one of the preceding claims, that the device is equipped with chemical, pressure, temperature, or electromagnetic sensors.

7. Device according to one of the preceding claims, that the cannula has an electrically insulating coating on its inside.

8. Device according to one of the preceding claims, since you r c h g ek enn z e i c hn e t that the cannula has at least one opening for draining liquids.

9. Device according to one of the preceding claims, that the housing is sealed liquid-tight against the cannula by a seal.

10. Device according to one of the preceding claims, that a silicate, PTFE or ceramic is used to coat the cannula, so that adhesion between accessories and aids in the wet is reduced.

11. The device according to one of the preceding claims, since it is known that a shifting of the aid in relation to increased fluid pressure at the application site is possible.

12. Device according to one of the preceding claims, that the aid is that the aid is a foil provided with conductor tracks, which carries an electrode arrangement at its free end that can be pushed out of the cannula.