DE3208849A1 - Cryogenic probe - Google Patents

Abstract

The invention relates to a cryogenic probe having a probe tip, this probe being designed such that formation of ice and hence the freezing effect of the probe are controllable. The probe operates by the Joule-Thompson effect using a gas which causes the cooling when it expands at a constriction. In known probes the gas is directly fed to an outlet after cooling which results in only a short residence time for the gas in the probe tip. The probe according to the invention is designed in a manner such that the cooled gas flows through a channel section after having passed through the constriction and thereby is in heat exchanger function with the wall of the probe tip before the gas is fed to the outlet. The length of this channel section increases the residence time and permits better control of the formation of ice. In addition, the length of this channel section is designed so as to be adjustable, so that the shaping of the freezing or the formation of ice on the tip between the constriction and the outermost end of the tip is adjustable.

Description

Title: Cryogenic Surgical Probe

Cold Surgical Probe The invention relates to a cold surgical probe Probe and in particular a cryosurgical probe with a probe body, which has a hollow probe tip with high thermal conductivity at one end respectively.

forms, with a first channel for supplying a pressurized Gas to the probe tip, with a second channel for discharging the gas from the Probe tip and with at least one narrowing in the area of the probe tip to the Cooling of the gas according to the Joule-Thompson effect.

A cryosurgical probe or a cryosurgical probe is known Instrument that has a probe tip that is made using the Joule-Thompson effect of a pressurized gas is cooled that flows through a constriction. The pressurized gas is via a Line or fed via a channel along the probe, one end of which Channel is provided with a narrow outlet opening which forms the constriction and which opens into a cavity in the probe tip. After passing through the constriction expands the gas and thereby cools it down, creating a Causes the probe tip to cool down or freeze, which then (cooling down or freezing) for freezing a tissue, for example during a cold surgery operation can be used.

The expanded gas enters a cavity from the probe tip cavity Channel a, between the line or the channel for supplying the gas and the Inner surface of the probe wall is formed.

Such a cryosurgical probe has been used in proven in cryosurgery. Nevertheless, this known probe has certain disadvantages, because the discharged, cooled gas is in direct heat exchange with the probe body respectively.

with the probe shaft outside the working area of the probe, with the result that this probe body or

Probe shaft is cooled outside the working area of the probe.

Furthermore, it is extremely difficult with this known probe, the To control ice formation at the probe tip, especially in its shape. If the ice formation does not take place in the appropriate form at the probe tip, the overall cooling effect of the probe is severely impaired.

Another major disadvantage of the known probe is that that the opening forming the constriction through which the gas enters the cavity of the probe tip occurs, can be easily blocked or clogged by foreign bodies, and that it is then necessary to take the probe apart to clean the opening or constriction.

Furthermore, a cryosurgical probe is known in which the gas is fed in the cavity of the probe tip through an annular channel, the surrounds a line arranged in the central region of the probe. That in the cavity the end of this line opening at the probe tip is provided with a circumferential flange, which has a smaller distance from the inner wall of the probe body. This results in a cooling of the gas when it passes through the ring-shaped Constriction passes through it. The cooled gas cools the probe tip in the required manner and then enters the conduit serving as the outlet.

This embodiment of a cryosurgical probe which (embodiment) a gas flow which is reversed in comparison to the known embodiment described first has, to some extent, avoids the problem of cooling the probe body outside of the work area, as the inflowing warm gas is inside Pipe outflowing, still cold Gas shields. This well-known version a cryosurgical probe is difficult to implement in practice. In addition, the ice formation at the probe tip corresponds both in terms of shape as well as the cooling effect does not meet the requirements, mainly because of the short residence time of the cooled gas in the cavity of the probe tip. At this known device, the gas is rather already discharged through the outlet before it was able to fully develop its cooling effect at all.

Another major disadvantage of known cryosurgical probes consists in the fact that thermally induced length reductions during the cooling process occur in the various components that make up the probe, resulting in significant Difficulties mainly because it leads to changes in the dimensions the constriction and thus also occur in the gas flow.

The object of the invention is first of all to provide a cold surgery To show a probe with the possibility of changing the shape and thickness of the To control or determine ice formation at the probe tip with high accuracy.

Furthermore, the invention is about a cold surgery To show a probe in which the probe shaft does not cool down during use and the # ice formation resp.

Ice ball formation is restricted to the probe tip only, i.e. on the part of the probe where ice formation is actually required.

Furthermore, the invention is about a cold surgery To show a probe in which the constriction required for the Joule-Thompson effect not so easily blocked or

becomes clogged, as is sometimes the case with known probes, and above all the arrangement and design of the individual structural parts ensure that changes in length that occur during the cooling process and that are caused by the thermal system so far compensated for the fact that they

do not change the effective cross-section of the constriction, ie. the The size and the effective cross-section of the constriction are kept constant.

To avoid the disadvantages of known probes and to solve the the above-mentioned tasks or. The problem is a cold surgery Probe of the type described above is designed according to the invention so that the second Channel for discharging the gas surrounded by the first channel for supplying the gas is that the constriction is provided in the first channel for supplying the gas, those in this channel and in the direction of flow behind the constriction in the probe tip or in the working area of the probe forms a channel section, which of the cooled gas is flowed through.

The advantage of the probe according to the invention over known probes consists mainly in the fact that a controlled, uniform cooling or icing the working range of the probe is reached. Improved ice formation is in Glide-shaped way around the probe tip or around the working area of the probe possible, due to the fact that the residence time of the cooled gas in the Probe tip is increased because the cooled gas is the part of the first channel or flows through the channel section which is arranged downstream of the constriction in the direction of flow is before the gas is discharged via the outlet or via the second channel.

Further developments of the invention are the subject of the subclaims.

Further features and advantages of the invention emerge from the following description of preferred embodiments.

The invention will now be described in conjunction with the aid of exemplary embodiments explained in more detail with the figures.

1 shows a longitudinal section through an embodiment of a cryosurgical probe according to the invention, wherein the forming the second channel Line for discharging the gas has been omitted; 1A shows a cross section accordingly the line A-A of Figure 1; FIG. 2 shows a longitudinal section through the probe according to FIG. 1, but showing the conduit forming the second channel; Fig. 3 a Longitudinal section through a further embodiment of a cryosurgical probe the invention.

Preferred embodiments of the invention are described below. The cryosurgical probe shown in Figures 1 and 2 consists of a hollow, tubular main probe body 1, which is supported by a section 2 made of stainless steel and is formed by a rounded probe tip 3, if the latter is made of silver and is attached to section 2 preferably by soldering. The used Materials were chosen for their high thermal conductivity, Instead Another material, preferably of silver, could also be used for the probe tip 3 a stainless steel or a stainless steel can be used.

The tip 3 is made in one piece with a tubular section 4, which extends into section 2 and there against the inner wall of the section 2 is applied so as to form a double-walled section for the probe, which consists of Silver as well as stainless steel and which extends over a length D along the probe axis extends.

The exposed silver probe tip as well as the double wall section D form the working area or working tip E of the probe on which ice is can form, as will be explained in more detail below.

A tubular connecting line 5 also made of stainless steel extends inside the probe body l so as to form an annular channel 6, Via which a pressurized gas is supplied to the hollow work area E of the SoA will.

The line 5 is from a main line part 5 'and from an extension 5 ", with the latter having a smaller resp.

has reduced cross-section and is connected to part 5 ', preferably by soldering or gluing.

The line part 5 ″ is at least partially within the tubular Section 4 and thus also within the hollow work area E, the smaller or reduced cross-section of part 5 ″ to adapt to the double wall section D the probe is necessary.

The extension or section 4 has an end section 4 ', which in the direction of the upper or peripheral surface of the tubular part 5 "after is drawn inside, so in the channel 6, which is used for supplying the gas, an annular Constriction J and to form a narrowed annular channel section 6 ', the is connected to the constriction J in the direction of flow of the gas.

A thermocouple T for measuring or monitoring the temperature of the Probe tip is located in the hollow work area E, as shown, in the direction of flow of the supplied gas downstream of the line 5.

During operation, the pressurized gas is supplied via channel 6 and cools down due to the Joule-Thompson effect in the area of the constriction J, in that the gas in the channel section 6t of the channel, i.e. behind the Constriction J expands. The narrowed channel section 6 'conducts the cooled gas to the foremost area of the probe tip and causes the cooled gas to come over a longer dwell time in the work area E remains before the gas is over the line 5 is discharged. This increases the cooling effect of the probe considerably increased or improved, which then also leads to improved ice formation on the Working area E or at the top of the work leads. By the arrangement of the end of the part 5 ″ within the Abbeitsbereiches E can be the shape of the ice formation steer; for example, the length of the part 5 "after the constriction J is small, ice can form in the form of a ball, while if the length mentioned is greater, a more egg-shaped or sausage-shaped ice formation is obtained will.

Several layers of ice are formed one after the other on the probe tip 3, as indicated by the broken lines F in the figures. It shows that the ice formation initially occurs in an area of the probe body that (Area) of the constriction J is adjacent and only then gradually over the work area E extends.

In addition to the controlled ice formation and the improved cooling effect is the cold gas discharged via line 5 through that supplied via channel 6 warm gas shielded, which means that a cooling and / or icing of the probe in the direction of flow before the constriction J is prevented.

The end section 4 'of the tubular extension or of the tubular Section 4 is at two points offset from one another by 180 ° with knobs or Notches 8 provided, as shown in Fig. 1A. This allows the Device can be adjusted or calibrated in order to achieve the necessary adjustment of the To achieve gas flow through the probe. Although the gas has passed the channel section 6 in flows through its entire area around the annular constriction J, it is anyway necessary to provide such wells 8 so as to provide the required gas flow to obtain, the size of these depressions 8 corresponds essentially to the gas flow or this determined.

Another embodiment of the invention is shown in FIG. This probe consists of the hollow probe body 9, which in turn is made of stainless steel and has a tubular conduit 10 made of stainless steel, which extends extends in the probe body 9 and opens into the probe tip, as shown in FIG Fig. 3 is shown.

The line 10 forms one with the inner surface of the probe body 9 annular channel 11, which is used for supplying the pressurized gas to the probe tip is used, the line 10 itself to m discharge the gas from the probe tip serves.

The line 10 consists of a line or pipe part 10 ', which with a front line or pipe part 10 ″ with a smaller cross section, for example connected by soldering.

This connection is made at an end portion 12 of the part 10 ', the (end portion) flared outwards, e.g.

is funnel-shaped expanded outwards, this hand portion 12 forms an annular constriction J in the outer channel 11. The annular narrowing J opens into a channel section 11 'of the channel 11, the (channel section) one Has reduced cross-section and extends in the direction of flow of the supplied gas adjoins the constriction J.

The section 12 is provided with recesses 13, which in turn are preferably are arranged offset from one another by 1800 and for setting or calibration serve the arrangement, as already described above.

In operation, the pressurized gas is supplied via channel 11 and then cools down due to the Joule-Tho # son effect when this gas passes through the constriction J enters the channel section 11 'behind this constriction. the The time required for the gas to flow through the channel 11 is essentially determined the increased residence time for the cold gas in the probe tip before the gas over the line 10 is discharged. This creates a maximum heat exchanger effect achieved, which leads to a significant improvement in the mode of operation of the probe section IT contributes.

This embodiment has essentially the same advantages as the embodiment according to FIGS. 1 and 2, but that shown in FIG Embodiment particularly suitable for small cryosurgical probes in which compact and space-saving training is particularly important.

The embodiments of the invention described above use materials which are selected from a thermal point of view to be the same or nearly the same Have thermal expansion coefficients. In addition, the training the Embodiments described chosen so that during the Cools a compensation process or a compensation for axial length changes is possible because the constriction J necessary for the Joule-Thompson effects is formed in this way is that a shifting of the lines 5 and 10 with such changes in length in axial direction is possible.

This is precisely where the cold surgery according to the invention differs Probe very much different from known probes in which thermally induced changes in length uncontrollable changes occur at the constrictions that are responsible for the Joule-Thompson effect required are.

In summary, the present invention creates a cryosurgical probe that has the disadvantages and probines of known probes avoids or eliminates the following points: 1. With conventional probes leads the discharged, cold gas to a cooling of the probe body outside of the actual work area. In the case of the cryosurgical probe according to the present one Invention, the discharged cold gas is effective through the supplied, still warm gas Gas shielded, which flows in the outer area of the probe and which in the heat exchange stands with the probe body and thus prevents the probe body or probe shaft is cooled outside the actual work area.

2. In contrast to known probes, the one according to the invention Probe or, in the case of the cold surgical instrument according to the invention, the cooled one Gas also after passing through the constriction in the arm exchange function with the Wall of the probe tip or the working area of the probe held before this Gas is discharged. This is a much improved as well as better Controlled cooling capacity for the probe is achieved as a controlled heat exchange takes place in the work area or at the probe tip, depending on from a controllable pressure drop of the cooled gas in narrowed channel section before the gas via the outlet or via the outlet line is discharged.

3. The cryosurgical probe according to the invention also allows a shape controllable ice formation due to the fact that the dwell time of the cooled gas in the working area of the probe by shortening it or extension of the narrowed channel section can be changed, which (Channel section) the cooled gas flows through after passing through the constriction. In this way, for example, a spherical or more elongated or Achieve sausage-like ice formation.

4. Narrow openings that act as constrictions for the Joule-Thompson effect are very easily blocked in known cryosurgical probes. the annular constriction in the invention can be very much due to foreign matter in the gas harder to be blocked.

5. Changes in length occur in the cold surgical probe according to the invention mainly only in a single direction parallel to the axis of the probe body on. For this reason, the training according to the invention is used for the Joule-Thompson effect necessary constriction not changed during the cooling process, as a reduction the length of the line which is used to discharge the gas, only leads to the fact that this line shifts in the longitudinal direction of the probe, the gas flow through it however, it is not affected.

6. The probe according to the invention has a particularly simple construction and is easy to assemble.

Other features and advantages of the invention are due to the above Designs are readily recognizable for a person skilled in the art and are in the area of inventive concept. In particular, it can be seen that the above Embodiments described and shown in the figures, the probe tip is rounded, for a treatment or

The tip of the probe can be used for cold surgery on the nerves also be designed point-like or tapering to a point so as to pass through enable the tissue. If silver is used as the material for the probe tip, so the probe tip can also be chrome-plated or hard chrome-plated for a better Corrosion resistance to maintain resistance to wear and tear to increase and to the resistance or resilience in general to enhance. Such additional treatment of the probe tip is practical no influence on their thermal conductivity.

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Claims (10)

Claims -.-.-.-.-.-.-.-.-.-.-.-.-.-.- ~ ~ ~ 1. Cold surgery Probe with a probe body that has a hollow probe tip with a high at one end having thermal conductivity, with a first channel for feeding under Pressurized gas to the probe tip, with a second channel for discharging the Gas from the probe tip and with at least one constriction in the area of the probe tip for cooling the gas according to the Joule-Thompson effect, characterized in that the second channel (5, 10) for discharging the gas from the probe tip (E, EE) the first channel (6, 11) for supplying the gas is surrounded, and that in the first channel (6, 11) a constriction (J) is provided in this channel (6, 11) and in the direction of flow behind the constriction (J) in the probe tip (E, EE) a channel section (5 ', 11') forms, which is flowed through by the cooled gas. 2. A cryosurgical probe according to claim 1, characterized in that that the second channel for discharging the gas from a preferably tubular Line (5, 10) is formed within the probe body (10, 9), which extends into the hollow probe tip (E, EE) opens, and that the first channel (6, 11) for feeding of the gas is arranged around this line (5, 10). 3. A cryosurgical probe according to claim 2, characterized in that that the probe body (1) or a section (2) thereof on a hollow section (4) the probe tip or a part (3) forming the probe tip is pushed on is to form a double wall (D) in which the inner wall is made of the material the probe tip (3) and around a part forming the end of the line (5) (5 ~) of this line is arranged and an end section (4 ') which has to form the constriction (J) in the direction of this part (5 ") of the Line (5) is constricted or narrowed, and that the channel section (6 ') of the first Channel (6) between the outer wall of the mentioned part (5 ") of the line (5) and the inner wall of the section (4) of the probe tip (3) is formed. 4. A cryosurgical probe according to claim 3, characterized in that that the end section (4 ') is preferably offset by 180 ° on two from one another Areas with indentations or incisions in order to allow an adjustment or Calibration of the probe with regard to the required gas flow rate through the mentioned constriction (J). 5. A cryosurgical probe according to any one of claims 2 to 4, characterized characterized in that the line forming the second channel for discharging the gas (5) from a main part (5 ') as well as from an adjoining part, the end the line forming part (5 ") with a smaller cross-section, and that the two parts (5 ', 5 ") preferably attached to one another by soldering or gluing are at a point in the direction of flow of the supplied gas the constriction (J) lies. 6. A cryosurgical probe according to one of claims 2 to 5, characterized characterized in that the line (5) is adjustably supported so as to make a change to allow the length of the part (5 ") with which the line (5) over the constriction (J) protrudes. 7. A cryosurgical probe according to claim 2, characterized in that that the second channel for discharging the gas forming line (10) from a Main part (10 ') and an adjoining end of the line forming part (10 ") with a smaller cross-section, the two parts preferably are connected together by soldering or gluing that the end of the main part (10 ') the junction between the two parts (10 ', 10 ") is widened so as to lie against the inner wall of the probe body (9) and there to form the constriction (J) in the first channel (11), and that the Narrowing (J) adjoining channel section (11 ') between the inner wall of the probe body (9) and the part (10 ") forming the end of the line (10). 8. A cryosurgical probe according to claim 7, characterized in that that the widened end or the widened section (12) with recesses (13), which are preferably arranged offset from one another by 1800 and those for calibrating or setting the probe in terms of definition serve the gas passage through the first channel (11). 9. A cryosurgical probe according to one of claims 2 to 8, characterized by a thermocouple (T), the connecting wires of which run through the line (5) in extend the probe tip. 10. A cryosurgical probe according to one of claims 2 to 9, characterized characterized in that the probe body (1, 9), the probe tip (E, EE) and the the conduit (5, 10) forming the channel for discharging the gas are made of stainless steel.