GB2079608A

GB2079608A - Directly cooled tip of cryosurgical apparatus

Info

Publication number: GB2079608A
Application number: GB8119618A
Authority: GB
Original assignee: VYZKUMNY USTAV SILNOPROUDE ELEKTROTECHNIKY
Current assignee: VYZKUMNY USTAV SILNOPROUDE ELEKTROTECHNIKY
Priority date: 1980-07-15
Filing date: 1981-06-25
Publication date: 1982-01-27
Also published as: FR2486799A1; GB2079608B; DD230150A3; AU7269481A; JPS5743736A; DE3124167A1; CS217449B1

Abstract

A cryosurgical apparatus has a body (Fig. 2) and a removable exchangeable cap 20 (Fig. 3) which is intended to contact the patient. The body has a central conduit 10 which has a valve 40 at one end and a coolant supply at the other end. The body also has channels 6 leading to a tube 11 for draining used coolant away. When the cap 20 is fitted on to the body, needle 26 opens valve 40 and coolant flows up into space 28 and back through channels 25 which are in communication with channels 6 and drain tube 11. <IMAGE>

Description

SPECIFICATION Directly cooled tip of cryosurgical apparatus The invention is related to a directly cooled exchangeable tip of cryosurgical apparatus for surgery.

The latest cryo-biological researches proved that the most effective crygenic destruction takes place when as low temperature of operating tip is used as possible, the temperature of which is established in as short time interval from the instant of bringing the apparatus into operation as possible. From this it follows that modern cryogenic apparatuses for surgery operate most frequently with liquid nitrogen and they make every effort to reach the maximum cooling effect in the operating tip.In the present practice heat exchanger is most frequently used placed in the operating instrument while operating tips are disconnectable as passive elements in ther mal contact with the instrument, thus creating a sub stantial thermal resistance in passage of thermal flow from tissue to the exchanger, which resistance is determined on the one side by a passage between exchanging tip and the instrument and on the other side by thermal resistance of the tip proper. From a simple calculation it follows that for example in the length of a silver operating tip having diameter 5 mm and length 50 mm temperature difference approximately 1 000C originates at thermal flow 15 Jigs.

The invention presented eliminates drawbacks of the known tips of cryogenic apparatuses for surgery, maximum efficiency being reached above all by that the exchanger contains porous filling from a mater ial with anisotropic thermal properties and it is placed directly in the exchangeable tip.

The nature of directly cooled exchangeable tip according to the invention consists in that, the heat exchanger with heat exchanging material is arranged in exchangeable tip provided with supply channel of cooling medium and with interconnecting small channels of cooling medium, while external contact area of the carrier of exchangeable tip being removably connected for example by a bolted con nection with internal contact area of the exchange able tip and the small tube for cooling medium sup ply, in which axis a valve is, if need be, placed, is arranged in the screw part of the carrier of exchangeable tip, and, the tube is connected to the supply channel of the exchangeable tip and inter connecting small channels of the exchangeable tip are connected with collecting channel of the carrier, internal contact area of the exchangeable tip fitting to the external contact area of the carrier and being provided with a mantle.

Higher effect as related to the known solutions of tips is reached using directly cooled exchangeable tip of cryosurgical apparatus according to the inven tion above all by arrangement of heat exchanging material directly in the exchangeable tip of the cryosurgical apparatus by what thermal resistance between surface of exchangeable tip and cooling medium is suppressed. Heat transfer from cooled tissue to cooling medium is improved.

An example of embodiment of directly cooled tip of cryosurgical apparatus according to the invention is schematically illustrated on the attached drawings where in Fig. 1 composition of working part of cryosurgical apparatus in longitudinal section is illustrated, in Fig. 2 carrier of the exchangeable tip in longitudinal section is illustrated, in Fig. 3 exchangeable tip in longitudinal section is illustrated, in Fig. 4 plug in partial longitudinal section is illustrated and in Fig. 5 valve in longitudinal section is illustrated.

The exchangeable tip20 in which heat exchanging material28 is placed is formed by a mantle 29 with needle 26. Mantle 29 is connected with a flange 21 in which connecting small channels 25, supply channel 27 and, if need be, internal packing 23 and external packing 24 are. The exchangeable tip 20 fits with its internal contact area 22 to the external contact area 16 of the carrier frame 1 of exchangeable tip 20. Tube 10 for supply of cooling medium into exchangeable tip20 comes through carrier frame 1. Valve 40 is placed in tube 10. Valve40 is formed by packing ring 41 on which packing ball 42 bears which is leant to perforated leading ring 43. In the lower part of valve 40 perforated carrier ring 45 is placed against which ring spring44 is leant.Collecting channel 5 and collecting small channels 6 are arranged in the frame carrier 1 for cooling medium drain off. On the carrier frame 1 thermometer 7 and heating winding 8 are placed. In order to ensure vacuum isolation casing 12 with lid 9, if need be, with vacuum casing 13 closing vacuum space 14 is arranged. Tube 11 for cooling medium drain off is soldered into the lid 9. Electrical leads to thermometer 7 and heating winding 8 are also led through tube 11 for cooling medium drain off. Carrier frame 1 is placed into tube 15 which is evacuated. Gas-tight joining of carrier frame 1 and exchangeable tip 20 is ensured by screw2 of the carrier of exchangeable tip 20 by internal packing edge3 andlor by external packing edge 4.

For gas-tight closing of the exchangeable tip 20 a plug 30 is arranged which is provided with screw 3 1 of the plug 30, contact area 32 packing internal contact area22, if need be, with edge33 of plug 30 packing external packing 24.

In an alternative embodiment valve40 and needle 26 can be left out, if need be, some of the packings and that is either external packing 24 or internal packing 23 or both packings can be left out. The same is true also about internal packing edge3 and external packing edge4 and about edge33 of plug 30.

Function of the apparatus is as follows: Exchangeable tip 20 is joined to the carrier frame 1. Cooling medium enters into exchangeable tip20 through small tube 10 which comes through carrierframe 1 of exchangeable tip 20. Heat transfer takes place in heat exchanging material inside exchangeable tip 20. Cooling medium drain off from exchangeable tip 20 is mediated by interconnecting small channels 6 and by a tube 11 for cooling medium drain off. Heating of exchangeable tip20 is ensured by heating winding 8. Temperature of exchangeable tip 20 is detected by thermometer 7.Gas-tight joining of exchangeable tip20 with carrierframe 1 is ensured by internal contact area 22 and external contact area 16, which areas are, if need be, provided with internal packing edge3 and external packing edge4 and internal packing 23 and with external packing 24.

Exchangeable tip20 is closed by mantle29, in the axis of which a needle 26 can be placed. In this case needle26, after joining exchangeable tip 20 with carrierframe 1, shifts aside packing small ball 42 or valve by what passage of cooling medium through packing ring 41 is enabled. Pressing of the packing small ball 42 in ensured by perforated leading ring 43 by mediation of spring 44 which is leant to perforated carrier ring 45. Valve 40 enables exchage of exchangeable tips 20 at keeping working overpressure in small tube 10 and it simultaneously prevents from condensation of atmospheric humidity inside this small tube 10.Flange21 fitting with internal thread to carrier frame 1 makes impossible communication between supplied and drained off cooling medium and between cooling medium and external atmosphere by means of internal packing 23 andlor by means of external packing 24, made of, for example, teflon.

Sterilization of exchangeable tips 20 is enabled by plug, schematically illustrated in Fig. 4, which plug with the help of screw3 7 ensures closing of supply channel 27 and interconnecting small channels 25 of the exchangeable tip 20 by pressing edge 33 of plug 30 onto external packing 24. Packing of exchangeable tip 20 to carrier frame 1 orto the plug 30 can be alternatively ensured by internal packing 23 and/or by external packing24 against external contact area 16 or contact area 32 or, if need be, by fitting internal contact area 22 to external contact area 16, if need be, to contact area 32 with the help of removable joint which is formed for example by a screw of carrierframe 1 of exchangeable tip 20, and by a thread in flange 1 of exchangeable tip 20.The condition of tightness is that surface straight lines of internal contact area 22 of exchangeable tip20 and surface straight lines of external contact area 16 of carrier frame 1 of exchangeable tip 20, which lines intersect the axis of exchangeable tip 20, include with these axes always equal angles. Another example of embodiment the packing between carrier frame 1 of exchangeable tip 20 is substitution of internal pack ing 23 and/or of external packing 24 by edges and substitution of internal packing edge 3 and/orexter- nal packing edge4 by packings.

Porous metallic filling is the most suitable as a heat exchanging material, arrangement of which fil ling ensures high thermal conductivity in directions perpendicular to the surface of exchangeable tip20 at decreased thermal conductivity in the direction of cooling medium flow through heat exchanging mat erial 28. Parallel arrangement of annulus of metallic, thermally well conductive grids or perforated foils, which are with their external periphery in thermal contact (for example by soldering) with the internal surface of the mantle 29 of exchangeable tip 20, is an example of arrangement suitable for the type of operations at which it is necessary to ensure the highest cooling efficiency in cylindrical area of the exchangeable tip 20 (for example proctologic operations). In the case of need to ensure the main cooling efficiency into front area of the exchangeable tip 20 (for example dermatologic or gynaecologic operations) it is suitable to form the heat exchanging material 28 for example of spiral-shaped wound up strip of metallic grid around the axis of exchangeable end piece 20 or of a system of co-axial cylinders, if need be, of a system of concentric hemispheres formed 4 from metallic grids or perforated metallic foils.

Claims

1. A directly cooled exchangeable tip of a cryosurgical apparatus for surgery, characterized by that, the heat exchanger with heat exchanging material (28) is arranged in exchangeable tip (20) provided with supply channel (27) of cooling medium and with connecting small channels (25) of cooling medium, while external contact area (16) of the carrierframe (1) of exchangeable tip (20) being removably connected with the internal contact area (22) of exchangeable tip (20) and the small tube (10) for cooling medium supply, in which axis a valve (40) is, if need be, placed, is arranged in the screw part of the carrier frame (1) of exchangeable tip (20), while the tube is connected to the supply channel (27) of the exchangeable tip (20) and connecting small channels (25) of the exchangeable tip (20) are connected with collecting channel (5) of carrier frame (1), internal contact area (22) of the exchangeable tip (20) fitting to the external contact area (16) of the carrier frame (1) and being provided with a mantle (29).

2. A directly cooled tip according to Claim 1, characterized by that, surface straight lines of the internal contact area (22) of exchangeable tip (20) and surface straight lines of the external contact area (16) of carrier frame (1) of exchangeable tip (20) intersect common axis of the exchangeable tip (20) and that one of carrier frame (1) of exchangeable tip (20) and include with this axis equal angle, while internal contact area (22) of the exchangeable tip (20) being to the external contact area (16) of carrier frame (1) of exchangeable tip (20) joined with a removable, for example bolted, joint.

3. A directly cooled tip according to Claim 1, characterized by that, the internal contact area (22) of exchangeable tip (20) is provided with an external packing (24) and/or with internal packing (23) and/or the external contact area (16) of carrier frame (1) of the exchangeable tip (20) is provided with external packing edge (4) andlor with internal packing edge (3).

4. A directly cooled tip according to Claim 1, characterized by that, the internal contact area (22) of exchangeable tip (20) is provided with an external packing edge (4) and/or with internal packing edge (3) and/or the external contact area (16) of the carrier frame (1) of exchangeable tip (20) is provided with external packing (24) and/or internal packing (23).

5. A directly cooled tip according to Claim 1, characterized by that, a needle (26) is fixed in the axis of exchangeable tip (20) to the internal surface of its mantle (29) and in the axis of small tube (10) for liquid cooling medium supply a valve (40) is placed.

6. A directly cooled tip according to Claim 1, characterized by that, the exchangeable tip (20) is provided with a plug (30) which is arranged as removable one and its contact area (32) is of the same shape with the internal contact area (22) of exchangeable tip (20) and/orthe plug (30) is provided with an edge (33) of plug (30), diameter of which edge corresponds to the middle diameter of external packing (24) of the exchangeable tip (20).

7. 7. A directly cooled tip according to Claim 1, characterized by that, the heat axchanging material (28) is made of well conductive metallic grids or perforated foils which are with their external perimeter in thermal contact with internal surface of mantle (29) of the exchangeable tip (20).

8. A directly cooled exchangeable tip of a cryosurgical apparatus for surgery substantially as described herein with reference to the accompanying drawings.