US3512531A - Method and apparatus for cryosurgery - Google Patents

Description

' May 19, 1970 RECRUMPETA; 3,512,531 METHOD AND APPARATUS FOR CRYOSURGERY Y I 3 Sheets-Sheet 1 Filed Jan. 11, 1968 INVENTORJ May 19, 1970 R'. E. CRUMP ET AL- METHOD AND APPARATUS FOR CRYOSURGERY File d Jan. 11, 1968 3 Sheets-Sheet 2 R. E. CRUMP ET AL METHOD AND APPARATUS FOR CRYOSURGERY May 19, 1970 Filed Jan. 11, 1968 3 Sheets-Sheet 5 United States Patent 01 iice 3,512,531 Patented May 19, 1970 3,512,531 METHOD AND APPARATUS FOR CRYOSURGERY Ralph E. Crump, Trumbull, and Frank L. Reynolds,

Monroe, Comm, assignors to Frigitronics, Inc., Bridgeport, Conn., a corporation of Connecticut Filed Jan. 11, 1968, Ser. No. 697,177 Int. Cl. A61b 17/36 US. Cl. 128-3031 12 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for performing a cryosurgical endarterectomy. A cryosurgical instrument has an elongated probe designed to operate below the freezing point along one side, the opposite side remaining relatively Warm. The probe is inserted into the artery and positioned in the demarcation between the adventitia and the diseased intima with its cold side in contact with the intima. The probe is then caused to cool and adhere to the intima. The probe and attached intima are then withdrawn from the artery.

BACKGROUND OF THE INVENTION Atherosclerosis is recognized as a major medical problem. This condition arises when a coating of fatty substances such as cholesterol deposits on or in the intima (endothelial) layer of an artery. This creates a constriction leading to serious and often fatal results. The current state of the medical art is such that blood cholesterol levels can be measured and some arterial restrictions can be diagnosed and physically located. Furthermore, a technique has recently been devised for removing the diseased intima.

The new surgical technique is known as gas endarterectomy and is founded on the fact that a zone of demarcation usually exits between the intima, with its deposit of cholesterol or calcified cholesterol, and the adventitia. In the gas endarterectomy procedure, a bolus of carbon dioxide is injected under pressure into the artery between the adventitia and the diseased intima. This pressurized gas acts as a dissecting medium and separates the intima from the adventitia. After his initial separation, the arterial section bein gtretaed is partially opened by longitudinal incisions and a gas spatula is employed to complete the separation. The inner core is then transected at its two ends and removed by means of an elongated clamp which is passed down the dissected plane of the blood vessel to grasp and withdraw the core. The arterial incisions are then closed in the usual manner.

The technique described above promises to be of substantial importanceparticularly in more advanced cases of atherosclerosis. However, the technique has one serious weakness. This is the final removal of the diseased intima. The intima has a somewhat soft consistency so that complete removal by means of a clamp or forceps is difficult. This is especially true in the treatment of long arteries, such as found in the legs, where a core of as much as twenty-four inches may be removed. If any residue of the intima remains in the artery, it may form the nucleus of a clot leading to thrombosis or stroke.

Accordingly, it is a primary object of the present invention to provide an improved method for removing the diseased intima of a blood vessel after dissection.

Other objects are to provide such a method which removes all the dissected intima; to provide an apparatus for practicing such method and to provide such an apparatus which operates upon the principle of cryoadhesion.

SUMMARY OF THE INVENTION The present invention is based upon the principle of cryoadhesion, or the adhesion of moist tissue to an object cooled well below freezing temperature. Cryoadhesion in and of itself is not new but has been used in other surgical procedures, such as cataract removal. For example, in US. Pat. 3,289,749 of Ralph E. Crump, there is disclosed a probe for such an application which is thermoelectrically cooled. Experience with that probe by a number of ophthalmologists has illustrated that cold metallic surfaces will adhere to warm moist tissue surfaces with sufficient adhesion to manipulate the tissue. In accordance with the present invention, there is provided a long, thin, and relatively flexible probe for insertion between the adventitia and intima of a length of artery. The probe is designed to be cooled along one side of .its elongated surface to adhere to the loosened intima while the opposite surface remains nonadherent with respect to the adventitia. Controls are provided to permit the probe to be inserted in its warm state and thereafter cooled. When adherence to the intima is complete, the probe is withdrawn, bringing with it the diseased portion of the intima.

BRIEF DESCRIPTION OF THE DRAWINGS An understanding of this invention may be best achieved by reference to the figures of the attached drawings wherein:

FIG. 1 is a perspective view of a cryosurgical instrument in accordance with this invention;

FIG. 2 is a vertical cross section of the instrument of FIG. 1;

FIG. 3 is a cross section taken substantially along the line 3-3 of FIG. 2;

FIG. 4 is an enlarged vertical section of the end of the probe portion of this invention;

FIG. 5 is a cross section taken substantially along the line 5-5 of FIG. 4;

FIG. 6 is a cross section taken substantially along the line 6-6 of FIG. 4;

FIG. 7 is an enlarged cross section taken substantially along the line 7-7 of FIG. 2;

FIG. 8 is a cross section taken substantially along the line 8-8 of FIG. 2;

I FIG. 9 is a view similar to FIG. 8 illustrating one step in the operation of the mechanism of the invention;

FIG. 10 is a view similar to FIG. 9 illustrating a further step in the operation of the mechanism of the invention; and

FIGS. 11-14 illustrate steps in a surgical procedure utilizing the apparatus of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With particular reference to FIG. 1, there is illustrated a cryosurgical instrument in accordance with this invention comprising a handle 10, an elongated probe 12, a control lever 14, a refrigerant inlet line 16, a refrigerant outlet line 18 and a carbon dioxide supply line 20.

Referring now to FIG. 2, the basic structural framework of the mechanism of this invention will be seen to comprise a chassis member 22 formed essentially of strap metal and including a widened front plate 24 and a circular rear plate 26. The front plate 24 is drilled to receive the reduced diameter ends of an inlet valve body 28 (FIG. 8) and an exhaust valve body 30. The construction of these valve bodies will he most apparent from FIG. 8 wherein it will be seen that the inlet valve body 28 includes an axial passageway 32 over most of its length which, at its forward end, is necked down to form a reduced diameter outlet 34. A tapered valve seat 36 is thus formed between passageway 32 and outlet 34.

The exhaust valve body 30 has essentially the same external configuration as inlet valve body 28. However, it is provided with an enlarged internally threaded opening 38 at its forward end and a smaller diameter passage 40 3 along its rearward length. A conical valve seat 42 is formed between opening 38 and passage 40. A threaded plug 44 is positioned in opening 38 and defines a fluid passage 46 terminating at a transverse slot 48 across the rear face of plug 44.

A resilient metallic inlet bellows 50 is mounted on the inlet valve body 28 and a similar exhaust bellows 52 is mounted on the exhaust valve body 30. A support block 54 is mounted on the rearward end of the inlet bellows 50 and supports the end of an elongated valve core 56. This mechanical support is achieved by means of a threaded plug 58 in the end of support block 54 which screws downward against the enlarged head 60 of the valve core 56. Valve core 56 extends forwardly through the bellows and into passageway 32. The valve core includes a conically tapered forward end 62 positioned within the valve seat 36. Forward end 62 defines along its tapered surface a narrow bleed slot 64. Extending rearwardly from plug 58 is threaded screw 66 which carries an internally threaded tubular stop member 68 positioned to engage rear plate 26. Also mounted on screw 66, but near plug 58, is a control nut 70.

Mounted on the end of exhaust bellows 52 is a support block 72 which defines a cylindrical recess 74 and an axial passage 76 communicating therewith. An exhaust valve stem 78 extends through passages 40 and 76 and is threaded along its rearward portion to carry a cylindrical actuator 80 which is mounted within recess 74 and a control nut 82. The forward end of the exhaust valve stem 78 is enlarged to define a conical valve face 84 arranged to seat within valve seat 42 and a cylindrical head 86 having a transverse slot 88;

A rectangular floating bar 90 includes a pair of openings which loosely engage screw 66 and exhaust valve stem 78 and bears against control nuts 70 and 82. The t control lever 14 is substantially L-shaped, as shown in FIG. 2 and is mounted in a pivot opening 92 in chassis member 22 with its short vertical leg extending downwardly and against the floating bar 90. The rear plate 26 is provided with a L-shaped slot 94 through which control lever 14 extends as shown in FIG. 3, the slot being further provided with a projection 96 for retaining the control member 14 in a depressed position.

The refrigerant inlet line 16 is connected through a suitable coupling 16a to a delivery tube 1619 which communicates with passage 32 in inlet valve body 28. The refrigerant exhaust line 18 is similarly connected through coupling 18a to exhaust tube 18b which communicates with passage 40 in exhaust valve body 30.

The valve mechanism contained in handle is enclosed by a tubular sheath 98 which, in turn, is closed at its forward end by a shaped finger piece 100. Finger piece 100 defines an axial opening 102 which carries a plastic sleeve 104.

The probe 12 portion of the instrument extends outwardly from the plastic sleeve 104 and includes a delivery tube 106 having one end connected in outlet 34 of inlet valve body 28 and a return tube 108 communicating with fluid passage 46 in plug 44. Fluid communication between the two remote ends of delivery tube 106 and return tube 108 is provided by a small hollow metallic tip member 110. The tip member 110 includes a tab 112- which extends rearwardly from the forward end of tip member 110 and in spaced relationship to tubes 106 and 108. Extending along the entire length of tubes 106 and 108 is a plastic insulator tube 114, molded to fit tubes 106 and 108 and bonded directly thereto, which defines a gas passage 116. The forward end of the plastic insulator tube 114 is securely retained in position on the probe by means of tab 112 which extends within gas passage 116 as shown in FIGS. 4 and 6. A carbon dioxide delivery tube 118 extends through handle 10 from the carbon dioxide supply line 20 and fitting 20a to insulator tube 114.

The operation of the mechanical features of the invention may be best understood by reference to FIGS. 8-10.

In considering the operation, it is to be understood that the refrigerant inlet line 16 is connected to inject refrigerant into the passageway 32 of the inlet valve body 28 while the refrigerant exhaust line 18 is connected to passage 40 of exhaust valve body 30. The opposite end of refrigerant exhaust line 18 may either vent to atmosphere or into a vacuum pump. It is also to be understood that the apparatus described herein will operate with a number of different fluids such as liquid nitrogen, precooled gases and liquids, and gases such as CO utilizing the Joule-Thompson effect. However, for purposes of this discussion, it will be assumed that a vaporizing liquid refrigerant is to be employed such as dichlorodifluoromethane, chlorodifluoromethane, bromotrifluoromethane, or mixtures thereof.

At the beginning of the operating cycle, which is illustrated in FIG. 8, the control lever 14 is in its uppermost position as illustrated in FIG. 3. The forward end 62 of valve core 56 is displaced from valve seat 36. This positive open position is maintained by the pressurized liquid refrigerant which fills the entire inlet bellows 50, the delivery tube 106, and the return tube 108 as well as the opening 38 in exhaust valve body 30. However, the liquid does not pass beyond opening 38 due to the fact that valve face 84 is seated tightly against valve seat 42. This results from the fact that exhaust bellows 52 is somewhat compressed and its normal resiliency forces actuator 80 toward the rear which, in turn retracts the exhaust valve stem 78. Thus, in the condition illustrated in FIG. 8 the probe 12, comprising delivery tube 106 and return tube 108, is warm due to its being completely filled with a relatively warm liquid. It will also be noted that excessive travel of valve core 56 is prevented by means of stop member 68 which abuts against the rear plate 26.

As actuation of the mechanism is begun, control lever 14 is depressed to position 14a illustrated in FIG. 3. It will be noted that the floating bar 90 is only loosely positioned over screw 66 and exhaust valve stem 78. It will also be recalled that inlet bellows is filled with pressurized liquid. Accordingly, the first step in the actuation,

, as illustrated in FIG. 9, is a cocking of floating bar 90 which forces control nut 82 and exhaust valve stem 78 forwardly against the lesser resistance of bellows 52. This moves valve face 84 away from valve seat 42, opening the system to exhaust. The inlet valve comprising valve seat 36 and the forward end 62 of valve core 56 remains open. This permits a flow of liquid refrigerant to pass through the delivery tube 106 and the return tube 108, thus clearing the system of any gas pockets or accumulations of moisture or oil Which might interfere with its operation. This also provides a warming position for rapid thawing if the probe has previously been refrigerated.

The final step is the full depression of control lever 14 into its stop position as illustrated 'by 14b of FIG. 3 In going from position 140: to position 14b, two things occur in sequence. First, the oulet bellows 52 is compressed even further and head 86 of exhaust valve stem 78 is caused to seat against the end of plug 44. This limits further travel of exhaust valve stem 78. Accordingly, further movement of floating bar is limited to compression of inlet bellows 50 by actuation of screw 66 to the position illustrated in FIG. 10. In this position, the forward end 62 of valve core 56 is seated firmly against valve seat 36. This would normally close the inlet valve but bleed slot 64 provides a metering passage for a small amount of liquid refrigerant which is forced through under pressure. The liquid refrigerant expands as it enters delivery tube 106 and vaporization continues throughout the length of delivery tube 106 and return tube 108, thus causing cooling of these tubes to temperatures well below freezing.

As the purpose of the instrument described herein is to adhere to the diseased intima, but not to the adventitia, it is important that one side of the probe be insulated to prevent adherence to the arterial wall. This is accomplished in the disclosed embodiment by means of a plastic insulator tube 114 which extends along the entire length of one side of probe 12. This tube is molded to fit the tubes 106, 108 and is bonded directly to them. The plastic material of the tube should be of a type which presents a smooth surface creating little or no adhesion or drag on adjacent tissue. Such materials may be, for example, polyvinylchloride, polytetrafluouroethylene or rubber materials such as urethane or silicone. Furthermore, this tube defines a gas passage 116, through which carbon dioxide from the carbon dioxide supply line 20 may be introduced. This gas performs two functions, first, it serves as a thermal insulating medium, secondly, in is suing from the end of the probe, it helps to separate the intima from the adventitia and thereby facilitates entry of the probe 12 into the diseased vessel.

Although it will be understood that the size and resiliency of the probe may be varied to suit the expected conditions, some values will be given to facilitate an understanding of the invention. For example, the length of the probe 12 may be from approximately four to twenty-four inches. The width, as viewed, for example in FIG. 7, may be from to 4 inch. The vertical thickness, as similarly viewed, may be from to A2 inch. The tubes 106, 108 may be of any suitable material, such as stainless steel.

An endarterectomy employing the method and apparatus of this invention is illustrated in FIGS. 11-14. In FIG. 11, the artery A selected for treatment is first isolated by means of suitable vascular clamps C. The gas needle N is then inserted tangentially into the arterial wall and carbon dioxide gas is introduced between the adventitia and the diseased intima. As the gas expands along the arterial section, it forces apart the intima and the adventitia. A longitudinal incision I is then made at one or both ends of the arterial section and a gas spatula S is Worked along the plane of separation between the adventitia and the intima to fully complete the separation. The gas spatula is aided in this task by means of carbon dioxide gas which passes through its handle and out through suitable openings in the forward end of the spatula. The diseased intima is now severed at each end of the arterial section unless both ends of the diseased portion are encompassed within the length of probe 12, and it can be removed complete. Thereafter, the probe 12 is inserted into the artery, along the plane of dissection, while the probe is in its warm condition. During insertion, carbon dioxide gas may be expelled from gas passage 116 to achieve a gentle separation of the intima from the adventitia. Other suitable fluids may be used for this purpose. The probe is inserted as shown in FIG. 13 in such a manner that the exposed metallic surfaces of delivery tube 106 and return tube 108 are in contact with the intima, while the adventitia is contacted only by the insulator tube 114. After complete insertion of probe 12, the control lever 14 is depressed and locked into its freezing position. Cooling of the probe begins immediately as disclosed above and soon forms a cryoadhesion to the intima. The probe is then carefully withdrawn, as shown in FIG. 14-, bringing with it the entire dissected portion of the intima. If a change of position of the probe is required, it may be easily thawed by releasing lever 14 to fill the probe with liquid Freon. After repositioning, the lever 14 may be depressed once again to achieve freezing. After extraction, the incisions I are closed in a standard fashion.

It will be understood by those skilled in the art that a number of variations and modifications may be made in this invention without departing from its spirit and scope. For example, instead of the hand held and hand actuated valving mechanism illustrated herein, a remote system may be employed whereby purging, freezing and defrosting may be controlled by someone other than the surgeon, for example, by means of mechanically, hydraulically, or electrically operated controls in the probe handle. Many other variations and modifications will also be apparent to those skilled in the art. For example,

the probe made he designed with an insulating sleeve along its entire length, leaving only the tip exposed for removal of clots and small blockages. Also, other structural modifications, such as a U bend in place of tip member 110 and differently shaped and positioned tubes and insulators may be employed. Accordingly, the foregoing description is to be construed as illustrative only, rather than limiting. This invention is limited only by the scope of the following claims.

What is claimed is:

1. In the method of performing an endarterectomy wherein a length of artery to be treated is isolated, an incision is made through the adventitia, and the itima is separated from the adventitia along said length of artery, the improvement which comprises: inserting into said artery, between said adventitia and itima, an elongated probe having a first surface in contact with said intima and a second surface in contact with said adventitia; cooling said first surface to form an adhesion between said first surface and said intima; removing said probe and adhering intima from said artery; and closing said arterial incision.

2. The method of claim 1 wherein said first surface comprises a refrigerated member and said second surface comprises a thermal insulating member.

3. The method of claim 2 wherein said refrigerated member comprises a pair of refrigerant-containing tubes.

4. The method of claim 2 wherein said thermal insulating member comprises a tube defining a fluid passage therethrough.

5. Cryosurgical apparatus which comprises: elongated flattened probe means having spaced first and second elongated surfaces; a delivery tube and a return tube in parallel relationship to define said first surface; fluid passage forming means at the tip of said probe interconnecting said delivery and return tubes; means for injecting a fluid refrigerant into said delivery tube to cool said first surface; means for exhausting said fluid refrigerant from said return tube; and thermal insulation means secured to said delivery and return tubes and forming said second surface.

6. Cryosurgical apparatus which comprises: elongated probe means having spaced first and second surfaces; means for injecting a fluid refrigerant into said probe means to cool said first surface comprising an inlet valve having an open position and a closed position and means forming a fluid bypass passage around said valve when in its closed position; means for exhausting said fluid refrigerant from said probe means; and thermal insulation means covering said second surface.

1 fining a bleed slot therein.

8. The apparatus of claim 6 wherein said exhausting means comprises an exhaust valve having an open and closed position.

9. The apparatus of claim 8 wherein said inlet valve is normally open and said exhaust valve is normally closed.

10. The apparatus of claim 9 further including means for opening said exhaust valve and thereafter closing said inlet valve.

11. The apparatus of claim 5 wherein said thermal insulation means comprises a tube defining a passage therethrough having an outlet at the end of said probe means.

12. The apparatus of claim 11 further including means for injecting a gas into said passage.

References Cited UNITED STATES PATENTS 3,228,400 1/1966 Armao 128303.1 3,289,424 12/1966 Shepherd. 3,298,371 1/1967 Lee 128-303.].

LAWRENCE W. TRAPP, Primary Examiner

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