Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1998-11-16
2001-04-17
Kennedy, Sharon (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S158000
Reexamination Certificate
active
06217557
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a device for injecting a substance into a body, especially human or animal, comprising a cannula or needle member and a dosing device for delivering a determined amount of substance to a target area, the dosing device having an attachment for the cannula or needle member. The invention also concerns a method for injecting the substance, comprising the steps of defining the target area, inserting a cannula or needle member in the body so as to position the tip portion of the member at the target area, supplying a determined amount of substance to the target area, and removing the cannula or needle member.
BACKGROUND OF THE INVENTION
In the medico-technical field, several methods of introducing liquid, with or without solid particles, into the body are already available. Most of these methods are based on the use of a needle or catheter in combination with some pumping device such as syringes or infusion pumps. In most applications, the volume of infused or injected liquid, liquid mixture or suspension is also relatively great relative to the dimensions or inner volume of the insertion system, which results in the influence of the system on the final position of the inserted fluid volume in the body being affected only marginally when withdrawing the insertion system. In most applications, the position of the deposition is also not decisive of the clinical efficiency of the infused substance.
In recent years, the requirements for accuracy of the deposition have increased dramatically in the field of, among other things, tissue implants. An example of fields where the accuracy of the deposition is highly decisive of the clinical result is the implantation of cells for treating Parkinson's disease. Cells which preferably are extracted from a foetus are suspended in a physiological solution, which is inserted to the desired position in the brain. The amount of suspended cells is in the order of 10 &mgr;l, which corresponds to the volume in a 10 mm length of the catheter by which the substance is introduced. Problems arise when the catheter system is being withdrawn, since a vacuum is generated which sucks back a great part of the infused amount to a non-desired position, resulting in the fact that the implanted cells cannot develop and contribute to a positive clinical effect.
SUMMARY OF THE INVENTION
The object of the present invention is to satisfy the requirements described above, while eliminating the drawbacks of prior-art systems.
A further object is to provide a method and a device, by which a substance which in medical contexts is suitable, can be injected with accuracy and in its entirety into a restricted and well-defined target area in a patient's body.
One more object of the invention is to permit the use of a flexible catheter for a simplified injection process.
According to the invention, these objects are achieved by a device according to the introductory part, which is characterised in that the cannula or needle member comprises a tube and a catheter displaceable in said tube, the outer diameter of the catheter being smaller than the inner diameter of the tube, thereby forming a gap between the catheter and the tube, essentially over the entire length of the tube, in that the proximal portion of the catheter is attached to the dosing device, and in that the distal portion of the catheter is, in connection with said injection, arranged adjacent to the distal end of the tube and forms a fluid-tight seal therewith.
A method for manipulating the device as described above is characterised in that the cannula or needle member is inserted into the body, the tip portion thereof being sealed by means of a sealing member which forms a fluid-tight seal with a surrounding tube of the cannula or needle member, in that the substance is injected into the target area by means of a catheter, which is surrounded by said tube and whose distal portion has, on the occasion of injection, been brought close to the distal portion of the tube, in that the catheter is then withdrawn from the body, thereby allowing air or gas at essentially atmospheric pressure to enter the space in the tube between the target area and the distal portion of the catheter, and in that finally the tube is withdrawn from the body and the insertion opening for the cannula or needle member is closed.
REFERENCES:
patent: 5116344 (1992-05-01), Sundqvist
patent: 5817072 (1998-10-01), Lampropoulos et al.
patent: 3539243 C3 (1987-05-01), None
Hakansson Hakan
Olsson Jan-Erik
Wallinder Jonas
Burns Doane Swecker & Mathis L.L.P.
Elekta AB
Kennedy Sharon
Serke Catherine
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