Surgery – Instruments – Light application
Reexamination Certificate
1998-12-03
2001-09-04
Dvorak, Linda C. M. (Department: 3739)
Surgery
Instruments
Light application
C606S010000, C606S007000, C606S202000, C606S013000, C606S014000, C606S185000, C607S089000
Reexamination Certificate
active
06283958
ABSTRACT:
The present invention discloses a laser application set, which is an interventional application set for minimum invasive laser-induced thermotherapy of soft-tissue tumors.
It is known as state of the art that laser radiation which emerges from an optical waveguide, e.g. the irradiation of an Nd:YAG laser at 1064 nm, employing a silica glass optical fiber (of the PCS, HCS or ALL SILICA type) as beam guidance system, may be used to cause radial-symmetric coagulation necroses in biological tissue. In order to do so, the light-conducting fiber is either placed upon the tissue or inserted into the tissue. However, the disadvantage of this method of therapy is that there occurs a high power density at the place of contact between fiber end area and tissue which, already above some 100 mW luminous power and depending on the fiber diameter, results in a carbonization of the tissue surface and thus, due to the high level of carbon absorption, prevents the further diffusion of radiation within the tissue.
Further an application device for laser radiation (DE4137983A1) is known, in which the beam-conducting end of the optical waveguide that faces the object to be treated is arranged in a tubular enveloping body whose front face is transparently shut to laser radiation, in particular in a plastic hose whose front end facing said object is air- and fluid-tight sealed, with the front face of the enveloping body and/or the end of the optical waveguide being equipped with a spreading device for laser radiation that has a spreading volume. There, also multiple chambered hoses are employed in order to provide possibly required cooling via a connected distributor piece.
Also known is a U.S. Pat. No. 5,312,392. A method of treating benign tumors”. In which a trocar, that contains an optical waveguide, is inserted into the tumor to be treated. The position of the trocar with the optical waveguide is monitored using ultrasound. The disadvantage of this method is that any repositioning of the trocar with the optical waveguide is only possible with a new puncture.
The disadvantage of all previously applied methods of therapy is that they fail to allow for a repositioning of the relevant enveloping body which contains the laser and, hence, any faulty positioning of the laser or the enveloping body, respectively, requires a new puncture. A further disadvantage is that with a defective laser wire (optical waveguide) yet another intervention into the soft-tissue tumor to be treated becomes necessary.
The object of the invention is the implementation of a laser application set which ensures a gentle treatment of a patient and facilitates monitoring by means of a computer tomograph or a magnetic resonance tomograph, respectively.
The aim of the invention is the creation of a laser application set which neutralizes the disadvantages of the prior art and the previous methods of therapy by providing an interventional application set for laser therapy which enables a repositioning and requires only a single puncture of the tumor to be treated.
The aim according to the invention is attained by implementing a laser application set in accordance with Nos. 1 to 9 of the patent claims.
The laser application set consists of an introducer tube with an internal stylet. The internal stylet is locked with the introducer tube by means of a thread. The internal stylet is designed in such a manner that it projects by approx. 1 cm over and beyond the end of the introducer tube and has a pointed form. The stylet is of a hollow construction. A grip end at the external end of the stylet may be used to undo its locking by turning, after which the stylet may be removed from the introducer tube. The proximal end of the introducer tube is provided with a T piece. A silicone lamella is placed between the T piece and the introducer tube proper in order to provide a high elasticity during the insertion into the respective tumor. The silicone lamella is designed as a silicone membrane in the form of a forward-folding buckling lamella. A hose lead with a downstream three-way faucet is connected to the T piece. The hose lead and the connected three-way faucet may be used to apply cooling agents, lubricants and/or other additional local anesthetics. This opportunity of supply essentially contributes to providing a largely painless therapy also for capsular lesions. In addition, the hose lead allows for blood control of the patient under treatment during the therapy session. An external thread to lock the stylet is located opposite the silicone lamella of the T piece. Moreover, the T piece is equipped with a membrane which prevents any fluids from leaking during the therapy session.
A further preferred embodiment is the provision of the introducer tube with marks which facilitate the exact positioning of the application set. The individual marks are appended at a distance of 1 cm from each other.
A further component of the laser application set is a tunneled catheter with an internal stylet. The tunneled catheter with the internal stylet is inserted upon the removal of the stylet from the introducer tube. The tunneled catheter is designed in such a manner that its distal end is air- and fluid-tight sealed and has a tunneled catheter tip which significantly contributes to the possibility that a repositioning may be made of the tunneled catheter in the tumor to be treated. The tunneled catheter is also provided with marks at a distance of 1 cm from each other which allow for an exact positioning of the tunneled catheter when inserted into the introducer tube. The beginning of the marking on the tunneled catheter is designed in such a manner that, upon reaching the first mark, the catheter projects approx. 30 mm from out of the introducer tube, which is important for the operability of the laser application set. Within the tunneled catheter there is an internal stylet whose end is equipped with a grip end for its removal. The internal stylet is made from stainless steel, which preferentially consists of a paramagnetic material. This stainless steel wire is wrapped with a synthetic sheathing. The essential fact is that the internal stylet provides stabilization to the insertion of the tunneled catheter into the introducer tube and, hence, enables the exact positioning of the tunneled catheter tip into the tumor to be treated. A further essential feature of the invention is that the introducer tube with the stylet as well as the tunneled catheter with its internal stylet are made from materials which may be used for the monitoring of the method of therapy by means of computer tomography (CT) or magnetic resonance tomography (MRT), respectively. The materials of the introducer tube and the stylet as well as the tunneled catheter are preferably from synthetic materials, with PE, PTFE, FEP plastics being employed.
The laser application set according to the intervention has the following advantages over the known application sets for laser therapies of soft-tissue tumors.
The marks appended to the introducer tube allow for an exact positioning of the introducer tube on the patient. The exact position relation of the laser application set to the lesion is of decisive significance for a successful therapy. Further, it can be established that the membrane located in the T piece of the introducer tube facilitates a safe and non-slipping positioning of the tunneled catheter according to the invention. The tunneled catheter is thermoresistant up to a max. 400° C. and its distal end is air- and fluid-tight sealed. The tunneled catheter, which thus prevents a direct contact between the laser applicator and the patient, is equipped with an internal stylet, consisting of a wire from paramagnetic material, that essentially contributes to the stabilization of the tunneled catheter during its insertion. Thus, on the one hand the tunneled catheter may be kept thin while, on the other, the required stabilization is still achieved. The marks appended to the introducer tube allow for an exact positioning of the introducer tube and prevent a fusion of the introduc
Kniep Frank
Mack Martin
Vogl Thomas
Dvorak Linda C. M.
Farah Ahmed
Kasper Horst M.
Somatex Medizintechnische Instrumente GmbH
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