Method of providing an implantation site in soft tissue
A method of providing a channel filled with aqueous gel in soft tissue comprises injecting a biocompatible aqueous gel into the tissue. Also disclosed is a corresponding device, the combination of the device and a guide for its insertion into tissue, and a system comprising the combination and a reservoir filled with aqueous gel comprising means for exerting pressure on the gel.
1 . A method for forming, with a device, a substantially straight channel filled with aqueous gel in soft tissue, the channel being used for subsequent insertion of structures in the micrometer range such as a thin filament, or an electrode of an optical fiber, the device comprising an oblong, rigid pin comprising a distal section extending from a distal end of the pin towards a proximal end of the pin, a central section extending from the distal section towards the proximal end making up an axial extension, and a proximal section extending from the central section to the proximal end, a central conduit extending from the proximal end to the distal section and closed at its distal end, the distal section having a diameter decreasing towards the distal end forming a sharp or blunt distal end facilitating insertion into the soft tissue, the central conduit providing fluid connection between a reservoir for aqueous gel, the pin in its central section comprising lateral passages extending radially from the central conduit and the lateral passages being distributed over the central section, the channel in the soft tissue that is filled with aqueous gel having a depth corresponding to a length of the pin measured from the distal end of the pin to a proximal end of the central section of the pin, and the distal and proximal sections not having lateral passages extending laterally from the central conduit, the method comprising:
inserting the device into the soft tissue;
supplying the aqueous gel outside of the central section via the central conduit and the lateral passages from the reservoir during insertion of the device by way of applying pressure to the aqueous gel to force neural tissue abutting the outer face of the central section away from the pin to form a layer of aqueous gel around the central section; and
withdrawing the device from the tissue while leaving the aqueous gel in the tissue thereby forming the channel filled with the aqueous gel, wherein the gel channel has a configuration enabling the structures to be inserted into the soft tissue without coming in direct contact with the soft tissue.
2 . The method of claim 1 , wherein the gel is native gelatin, recombinant gelatin, cross-linked gelatin and combinations thereof.
3 . The method of claim 1 , wherein the gel is carbohydrate or protein gel.
4 . The method of claim 3 , wherein the carbohydrate gel is selected from the group consisting of arabinogalactan gel, arabinoxylan gel, galactan gel, galactomannan gel, lichenan gel, xylan gel, hydroxymethylpropyl cellulose gel and gels of other gel-forming cellulose derivatives.
5 . The method of claim 3 , wherein the protein gel is selected from the group consisting of whey protein gel, soy protein gel, casein gel.
6 . The method of claim 1 , wherein the tissue is nervous tissue.
7 . The method of claim 1 , wherein the reservoir comprises a compressible reservoir wall and mechanical pump for exerting pressure on the gel.
8 . The method of claim 1 , wherein the device is mounted at the site selected for forming the channel by means of an insertion guide comprising a tubiform element into which the device is insertable and in which it is displaceable in an axial direction.
9 . The method of claim 8 , wherein the device is kept in a first position in the tubiform element in which position the outer openings of the lateral passages are closed by the tubiform element.
10 . The method of claim 9 , wherein the device is kept in a second position in the tubiform element in which a distal and a central portion of the device extends from a distal opening of the tubiform element and in which the outer openings of some or all openings of the lateral passages are not shielded by the tubiform element, which second position is one in which the distal and the central portion of the device is inserted into the soft tissue.
11 . The method of claim 1 , wherein the distal section of the pin narrows towards the distal end of the pin.
12 . The method of claim 11 , wherein the pin is cylindrical form, optionally except for at its proximal end.
13 . The method of claim 1 , wherein the device is of metal and/or polymer.
14 . The method of claim 1 , wherein the device comprises an electrode or optical fiber.
15 . The method of claim 1 , wherein the aqueous gel is cross-linked.
16 . The method of claim 1 , wherein the aqueous gel when pressed out from the openings, forcing the tissue abutting the outer face of the central section away from the pin to form a layer of aqueous gel around the central section.
17 . The method of claim 1 , wherein the aqueous gel preventing shrinkage of the channel inwardly thereby stabilizing the geometry of the channel.
18 . The method of claim 1 , wherein the reservoir is disposed at the proximal end of the conduit.
19 . The method of claim 1 , wherein the lateral passages disposed in the central section are arranged at regular axial distances.