Surgery – Instruments – Surgical mesh – connector – clip – clamp or band
Reexamination Certificate
1999-03-01
2001-05-22
Jackson, Gary (Department: 3731)
Surgery
Instruments
Surgical mesh, connector, clip, clamp or band
Reexamination Certificate
active
06235041
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a medical device of a biocompatible material for use in the treatment of a gap or defect in the central nervous system.
BACKGROUND OF THE INVENTION
Treatment that promotes functional regeneration across a complete spinal cord transection in man does not exist. In animal experiments (
1
), recovery after incomplete spinal cord lesions has been achieved in adults treated with myelin-associated protein antibodies while recovery after complete lesions has been demonstrated in neonates (
2
).
Various attempts have been made over the years to find a replacement for direct nerve stump to nerve stump suturing. Much research has focused on the use of channels or tubular prostheses which permit the cut ends of the nerve to be gently drawn into proximity and secured in place.
All prostheses produced so far are intended for peripheral nerves such as U.S. Pat. No. 3,833,002, U.S. Pat. No. 4,759,764, U.S. Pat. No. 4,870,966 and SE 457 598.
SUMMARY OF THE INVENTION
The present inventors have now found that mobility can be restored in rats having complete spinal cord gaps. The gaps have been bridged with multiple intercostal nerve grafts redirecting specific pathways from white to grey matter, and the grafted area stabilised by acidic fibroblast growth factor-containing fibrin glue and compressive wiring of posterior spinal processes. Nerve bridges were created between the peripheral nerves and the spinal cord.
It has also turned out that motility can also be resored under certain circumstances when grafting white to white and grey to grey mass if special antibodies are given to the person being treated or incorporated into inserted material connecting the gap ends of the spinal cord.
The invention relates to a medical device of a biocompatible material for use in the treatment of a gap or defect in the central nerve system comprising one or more means containing connections such as holes or channels arranged for receiving nerve growth promoting materials or substances, which device has a proximal and a distal end area comprising openings from the connections, characterized in that the device is marked and arranged for coupling nerves from the grey and white matter of the central nervous system at the proximal end to certain marked areas in the proximal end area and nerves in the grey and white matter at the distal end to certain marked areas in the distal end area.
The device may be marked and arranged for coupling nerves from the grey matter of the central nervous system at the proximal end to nerves in the grey matter at the distal end and nerves in the white matter of the central nervous system at the proximal end to nerves in the white matter at the distal end. This is especially the case when antibodies are administrated in order to promote the nerves to grow together.
In a preferred device according to the invention the device or the means is marked and arranged for redirecting nerves from the grey matter of the central nervous system at the proximal end to nerves in the white matter at the distal end and nerves in the white matter of the central nervous system at the proximal end to nerves in the grey matter at the distal end.
The device can be used in the treatment of complete or partial gaps or defect in the central nervous system. It may consist of one or more means comprising holes or channels arranged for receiving nerve growth promoting materials or substances, which device has a proximal and a distal end area comprising openings from the holes or channels. The openings and/or the end areas may be marked for easily coupling nerves in the grey matter of the central nervous system at the proximal end of the gap to nerves in the white matter of the central nervous system at the distal end and nerves from the white matter in the distal end to nerves in the grey matter of the proximal end.
The expressions proximal and distal refer to direction to and from the head respectively of the individual receiving the transplant.
Preferably the device redirects descending motor pathways from proximal white to distal grey matter, and ascending pathways from distal white to proximal grey matter.
The device may consist of one means that has a substantially cylindrical form comprising channels bridging openings in a first part of the area of the proximal end and openings in a second part of the area of the distal end and channels bridging openings in the second part of the area of the proximal end and openings in the first part of the area of the distal end.
The end area can have any suitable form and be planar or non planar such as curved or spherical.
In another embodiment of the invention the device may comprise one or more means having a substantially flat or plate like form. Tubes of biocompatible or biodegradable material containing growth promoting material and/or Schwans cells and/or one or more peripheral nerves are threaded through the holes of the plate or plates. When using a nerve fibre or bundles of nerve fibres the tubes may not be needed.
It is preferred to use as many fine nerves as possible. In the experiment with rats described below 18 peripheral nerves were used to bridge one gap of the spinal cord. It has turned out that it is possible to use even more nerves. Therefore it is postulated that up to 200 nerves may be used on humans, such as 25-150, preferably 50-100 nerves.
It is also possible to use a device having one or more means with substantially cylindrical form and one or more means having a substantially flat or plate like form. One means with cylindrical form can be surrounded by one or more means with plate like form.
The means may also be one or more tubes of a biocompatible material to be filled with the growth promoting substance and put in place in the spinal cord. The invention also relates to the use of such tubes. The device and means may also have other forms and can e.g. be moulded to suit the subject to be treated
When plates only are used they may be threaded with bundles of nerves or with tubes of the biocompatible material filled with the growth-promoting substance. Thus the device may also comprise one or more plates and tubing to be filled when used.
In order to facilitate the redirection of the grey and white matter, the areas of the proximal and distal ends respectively of the means are divided in a first and a second part. The first and the second areas may have any form. It is possible to simply divide the end area in two parts, that may be of the same or of different size. Preferably the first area is a central area and the second area is a peripheral area situated substantially around the central area. It is however also possible that the areas have one or more parts thereof intermingling or sticking into each other with or without connection(s) to the main part area.
Preferably the device consists of one cylindrical means having a first peripheral part and a second central part of the proximal and distal end area connected to the white and grey region respectively of both ends of the gap. Channels going from the peripheral part of one end are being redirected to end up in the central part of the other end of the cylinder and vice versa.
In order to enhance long distance regeneration it is preferable to let one or more channels or bundles of nerve fibres pass the gap and insert the end of the nerves or channels further down the spinal cord. Therefore the device or the means may have some of the channels ending at the side area and not at the distal end area. For example a nerve is introduced in the white matter of the proximal end of the gap and led through a channel that opens up in the side area of the device. It is then introduced through the white matter further down beyond the gap into the grey matter.
The means of the device may be marked. The first part of the proximal end area may be marked in the same way as the first part of the distal end area as is shown in
FIGS. 1
a
and
1
b.
When the device comprises one cylindrical means the first (peripheral) part of both end areas can be
Cheng Henrich
Olson Lars
Jackson Gary
Karolinska Innovations AB
Young & Thompson
LandOfFree
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