US3253594A - Peritoneal cannula - Google Patents

Description

May 31, 1966 F. E, MATTHEWS ETAL 3,253,594

PERITONEAL CANNULA Filed July 5o, 1963 INVENTORS BY l United States Patent O 3,253,594 PERITUNEAL CANNULA Frank E. Matthews, 2020 Add Drive, Falls Church, Va., I2`1/1Inl Kevin G. Barry, 905 Hyde Road, Silver Spring,

Filed July 30, 1963. Ser. No. 298,711 Claims. (Cl. 12S-348) This inventionrelates generally to a cannula. In particular, the present invention is concerned with a peritoneal cannula which can effectively seal a perforation in body flesh and which can be retained in position in the perforation along with any tubular element which is inl sertable through the cannula.

A number of insertion devices have been previously known in the art; however, for a variety of reasons, such devices have not been successful in preventing, for example, the infection that often occurs in the perforated flesh, due to the ineffective sealing of the perforated tissue from fluids contained in the peritoneal cavity. The known prior art insertion devices have also. not solved the persistent problem of preventing undue irritation in the perforation of the tissue, whether caused by normal movement of the patient or necessary manipulation of the devices by those administering to the patient, thus necessitating frequent withdrawals of the ,device and a consequent loss in effectiveness of the treatment. Further, these known prior art devices have required surgical implantation and subsequent suturing, in order to similarly achieve even the ineffective sealing previously experienced, and required surgery to remove the device.

Inflatable devices are also known which are4 designed to be used within a body. Devices of this nature are typified by the Wallace patent, No. 2,667,875; however, these inflatable devices in general, and the Wallace catheter in particular, do not effect any sealing of a perforation, but rather are to be used within a natural body cavity.

Accordingly, it is a principal objective of the present invention to provide a cannula which effectively seals a perforation made in the tissue.

It is a further object of the present invention to provide a novel cannula which is adjustable, pressure-sensitive, self-retaining, and introduced through standard trocars which is maintained substantially free from contact with the perforated tissue.

Another object of the present invention is to provide a cannula which can seal a perforation and retain itself in position along with any tubular device inserted through the cannula irrespective of thte normal movements of the patient.

A further object of the present invention is to produce tension in the cannula in order to draw the balloon attached to the end of the cannula tightly against the flesh surrounding the perforation.

This invention has as a further object the provision of a novel cannula which is self-adjusting when in position in a perforation and will be responsive to increases in natural internal body pressures to effect a greater sealing with the lowest possible initial pressure against the flesh surrounding the perforation when positioning the cannula in the body.

Another object of this invention is to provide a cannula having a balloon sealing means which can be collapsed beyond one end of the cannula, in order to permit the insertion of the cannula and balloon through a trocar having substantially the same internal diameter as the external diameter of the cannula.

A further object of the present invention is to provide a peritoneal cannula in which the end of the cannula can be trimmed in accordance with generally accepted surgical practice for an aseptic technique without deflating the ice sealing balloon, and which is economical to produce and disposable afte use.

These and other objects and advantages of the present invention will become apparent to those skilled in the art, from the following description when read in conjunction with the accompanying drawing, wherein:

FIGURE 1 is a side elevational View of the peritoneal cannula, partly broken away, according to the present invention, showing the cannula in position through a perforation in body tissue;

FIGURE 2 is a cross sectional view along lines 2 2 of FIGURE l, showing particularly the cannula holding and constriction assembly means and the inflated balloon embedded in position in the flesh surrounding the perforation;

FIGURE 3 is a cross sectional view on an enlarged scale taken along lines 3 3 of FIGURE 2, and

FIGURE 4 is a perspective view of a modification of the flange portion of the cannula holding and constriction assembly means.

The present invention is a peritoneal cannula for positioning in a perforation in a body that includes a cannula holding and constriction assembly means which is axially movable along one end of the cannula and which cooperates with an inflatable balloon surrounding a disc at the other end to retain the cannula inv a predetermined position about a perforation in the flesh and in which the balloon contacts the flesh only at a distance from the :perforation in the flesh and is self-adjusting, depending upon the internal pressure in the body. The holding and constriction means enables the cannula to be positioned by itself through a perforation in the flesh or may be used as an insertion device which receives a tubular element through the cannula and which, when in position, secures the tubular member to the cannula.

FIGURE 1 is 'a showing of the peritoneal cannula designated generally by the numeral 10. The material of which the peritoneal cannula is composed should be one that is flexible, easly sterilized and inexpensive, and most importantly, one that will not irritate the flesh upon any contact between the cannula and the flesh. Also, it is important that upon inflation the balloon will not distort, but will assume the predetermined shape. Accordingly, it has been found that the peritoneal cannula should be made of plastic material, such as polyvinyl, polypropylene, or polyethylene. Also shown is a tubular element 12 which may have perforations 14 at one end and which may be used as a fluid withdrawal or insertion device. The tubular element or tube 12 also represents any one of a number of devices which can be used for taking'measurements, photographs, a catheter for injecting or withdrawing fluids, or otherwise treating interior portions of the peritoneal cavity.

The peritoneal cannula 10 includes a cannula 16 0f sufficient length to be inserted into a perforation. At the end of the cannula 16 is provided an inflatable balloon 1S, which is shown to be ring-shaped; however, this shape is not critical, since the balloon should have a configuration depending upon the end outline of the perforation P in the flesh F. It is important for the balloon 18 to encompass the .perforation P and bear against the flesh F at the contact area 20 surrounding the perforation, which, as shown is substantially removed from the perforation. A connecting disc 22, which may be annular, is provided. This disc is secured at its inner circumference 24 to the flared end portion 26 of the cannula 16, in order to position the Contact area Ztl of the balloon at a distance from the perforation. The disc, as shown in FIG- URE 2, is uniformly thinner in longitudinal cross section than said balloon when said balloon is inflated.

The balloon 18 may be inflated by liquid such as saline solution through lumen 27, which is suitably secured as by fusing to the lower sheet and is further connected to and passes through the disc 22 at 36.

The balloon 18 is shown to be formed of upper and lower sheets 28 and 30 of plastic, which are fused at the outer circumference 32 of the inner annular portion forming the disc 22. The outer diameter of disc 22 should be atleast one and one-half the diameter of the perforation, as best shown in FIGURE 2.

In order to form the balloon 18, which may be of ring or toroidal or similar shape, it is desirable to use a flat piece of plastic for the lower sheet 30, and the upper sheet 28 should be Vacuum formed into a raised curve prior to sealing the upper sheet to the lower sheet, in order that the disc 22 may be more remote from the contact area 20, thus allowing greater depression of the disc by either internal body pressure or tension on the cannular Without the disc coming in contact with the perforated flesh. As shown the disc 22 is eccentrically positioned relative to the balloon.

It is to be noted that the upper portion of the balloon forms a smooth contact surface at 20 which avoids irregularities when the balloon is inflated. Because of the shape of this contact area, which may be curved as shown, the contact area 20 of the balloon will embed into the flesh upon tensioning of the cannula. FIGURE 2 clearly shows this important result of the present invention. It can be seen that forming the balloon with a depressed or fiat center, such as disc 22, permits the tissue to form greater contact with the balloon and thereby provide a greater seal.

The disc 22, therefore, performs a Variety of functions, the first having been described as enabling increased contact forming a secure seal between the balloon and the flesh at a point removed from the perforation; the second is to receive the lumen 27 for passage from the underside of the balloonv into the perforation; the third is to provide a strong connection between the inner edges of the balloon and the cannula which will enable the balloon and disc t-o be collapsed in front of the cannula and to a size substantially the same as the diameter of the cannula, and thus not require a particularly large perforation; and a fourth is to increase the uncounterbalanced area responsive to internal body pressure such that in-l creasing natural internal body pressures, occurring as during coughing of the patient, will tend to seat the contact area further into the flesh and further allow sealing with the lowest possible pressure of the contact area on the flesh and the lowest possible tension on the cannula, thus enabling the peritoneal cannula to be self-compensating and maintain proper sealing during variations in internal body pressure.

In order to maintain the cannula in position in the perforation P, there is provided a cannula holding and constriction assembly means, shown generally at 38 in FIG- URE 2. This assembly means is composed of a flange portion 40 which extends radially at least as far as the contact area 20 of the balloon and thus provides its own contact area 42 in alignment with and directly opposed to the contact area 20 of the balloon. Thus it can be seen that pressure exerted upon the flange 40 and maintained by the assembly means 38 will embed the balloon 18 and the particular contact area 20 into the flesh, thus providing a more effective seal of the perforation P from the fluids in the peritoneal cavity.

The cannula holding and constriction means includes a flange portion 40, which is provided with a neck 44 having threads 46 on its exterior. The neck portion 44 is receiVed in a cap 48, which has internal threads. The flange portion 40 and the cap 48 are axially movable along the cannula 16 when cap 48 is in loosened posit-ion and are provided with gripping means and 52 on the cap and neck, respectively.

As best shown in FIGURE'Z, an O-ring 54 is positioned in the cannula and operates to reduce the size of the passageway S6 in the cannula 16. The diameter of the O- ring is slightly larger than the inside diameter of the cannula, and thus creates a protuberance 58 in the wall of the cannula. This protuberance is positioned with the gripping means 50 and 52, located on either side, and when the cap 48 is in a non-tightened position, gripping means 58 and 52 are separated to such an extent that they are not both in contact with the protuberance. Accordingly, it is possible for the entire assembly means 38, in-

cluding the O-ring 54, to move axially up and down the. Y-

cannula, since upon movement in any direction, one or the other of the gripping means will bear upon the O-ring through the cannula Wall. As shown, the gripping means 50 and 52 cannot be separated to the extent that the O- ring would be dislodged upon movement to a position in which its axis is not coincident with the axis of the cannula.

Upon moving the cap 48 towards flange 40, gripping means S0 in the cap will come to bear upon the O-ring through the cannula wall and move the O-ring to a position in which it abuts gripping means 52 again through the wall. Further tightening of the cap will force cam surfaces 60 and 62, positioned on gripping means 50 and 52, respectively, into a distorted condition, whereby the passageway S6 through the O-ring will be substantially decreased in size. Such reduction in size of the passage- Way will maintain any member-such as, for example, tubular member 12-that may be inserted into the cannula firmly in place. Also, whether or not the tubular member 12 is present, the distortion of the O-ring and frictional engagement of the gripping surfaces and their yrespective cams upon the sharp curves produced at the protuberance 58 of the cam will prevent any axial movement of the assembly means 38. Thus the assembly means will maintain the pressure exerted by contact area 42 upon the iiesh F, maintaining a tight seal at contact area 20 around the balloon, which creates tension in the portion of the cannula between the O-ring and the balloon.

In use the peritoneal cannula may be easily and simply positioned Within a body through a normal trocar (not shown) by collapsing the balloon after it has been deated by removing the fluid through the lumen 27 and collapsing the disc 22. After the balloon has been inserted through the trocar and int'o the perforation P, the balloon is to be inflated through the lumen, preferably by liquid saline solution, and aktension force applied upon the cannula 16. This tension automatically positions the balloon around the perforation and at a suilcient distance from the edge of the perforation. With the cap 48 loosened so that the cannula holding and constriction assembly means 38 may be moved axially along the cannula 16, the flange 40 with its contact area 42 may be moved into place in contact with the flesh to exert pressure against the flesh holding the cannula under tension, thereby causing contact area to seat in the flesh. With the flange 40 so held in position and with application of the proper amount of pressure to form a securing seal between the balloon and the flesh surrounding the perforation, the cap 48 may be tightened, in order thatthe gripping means 50 and 52 with their cams 60 and 62 may frictionally engage the O-ring through cannula 16 and maintain the assembly means 38 in position and maintain the pressure of the flange 40 and its contact area 42 as applied to the flesh. Upon tightening of the cap 48, the O-ring 54 will deform to reduce and constrict the passageway 56 to hold securely any member, such las tubular member 12, which is passed down through the cannula. Regardless of whether any tubular member such as 12 is positioned in the cannula, the pressure of the contact area 42 will be maintained. In the event that no instrument is to be placed down through the cannula 16, a complete closing of the cannula 16 can be accomplished by any suitable clamp or surgical cord (not shown), which deforrns the cannula 16 to completely close passageway 56.

As shown, the lumen 27 passes through disc 22 at 36 and into the perforation P and out beneath ange 40. It is also possible to provide liange 40a, as shown in FIGURE 4, having a slot 64, through which the lumen may pass. The liange 40a has a neck 44, as previously described.

It will be understood that there are numerous advantages of the present invention which have been already disclosed. In addition, it has been found that with the present cannula, any tube that is passed down through the cannula is not held rigidly, except by the O-ring, thus enabling the inner end of the tubular member, whether it has perforations or whether it be a probe or sensor, to have some movement which is particularly advantageous in the event body fluids are to be drained completely, since it is known that such uids often tend to accumulate in pockets and are not necessarily in one location.

It is also important in that the cannula holding and constriction means is adjustable, which enables the device to be used regardless of the width of the liesh and the length of the perforation, thus enabling the device to be used in small children, or large obese adults. Also, in situations of dialysis or other required entrances into a body cavity, the device, according to the present invention, eliminates the requirement of a re-puncture for each redialysis.

A further important advantage of the present invention is the fact that the device is so simple that it can be installed with a minimum of preparation. The training required to insert the peritoneal cannula, according to the present invention, can be obtained simply and easily.

A further advantage of the present invention is that the end of the cannula can be cut olf in accordance with common medical practice without the delia'tion of the balloon.

From the foregoing detailed description, it will be evi- -dent that there are a number of changes, adaptations, and

modifications of the present invention which come within the province of those skilled in the art. However, it is intended that all such variations not departing from the spirit of the invention, be considered as within the scope thereof as limited solely by the appended claims.

We claim:

1. A cannula for sealing va perforation in flesh that forms a cavity in a body and for releasably securing to said `body comprising: an elongated cannula having a passageway, an iniiated balloon surrounding one end of said cannula, separate connecting .means secured to one end of said cannula and radially outwardly to said balloon, said balloon being positioned radially outwardly from said cannula at the point of intersection of the balloon and said connecting means, said separate connecting means being uniformly thinner in longitudial cross section than said balloon when said balloon is inflated, said balloon in intiated condition having a radially outwardly extending surface facing the other end of said cannula forming a first Contact area, a lumen extending substantially the length of the cannula and passing through at least a portion of said connecting means and secured so as to be in iluid communication with said balloon, said iirst area bieng radially spaced from said cannula and adapted to be substantially spaced from the edges of said perforation by said separating means so as to provide a irm contact between the balloon and the liesh, cannula holding means positioned on said cannula for axial movement along said cannula to impart tension to said cannula in order to maintain said first area tightly against said flesh, said holding means including a second contact area facing said first area in order that pressure exerted by said second area towards rst area embeds said first area into the flesh around but substantially spaced from said perforation to effectively seal said perforation Afrom said cavity, and pressure maintaining means included in said holding means for maintaining pressure of said second area towards said first area.

2. The cannula of claim 1, wherein the lumen is independent of said cannula and passes entirely through said connecting means and is secured to the opposite side of said balloon from said first contact area.

3. The cannula of claim 1, wherein the connecting means is in the-form of a at flexible disc having a di.- ameter greater than that of the perforation.

4. The construction of claim 1, wherein the connecting means is eccentrically positioned on said balloon and is remote from the iirst contact area to permit greater depression of said connecting means without contact with the iiesh.

5. A cannula for sealing a perforation in flesh that forms a cavity in a body and for releasably securing to said body, comprising: an elongated cannula having a passageway, an inflated balloon surrounding one end of said cannula, connecting means securing said balloon to said cannula, said connecting means extending radially 1outwardly 'of said cannula to increase the effective pressure area of Isaid balloon, said connecting means being in the form of a ilat disc secured to the end of the cannula to permit the balloon to be folded .to have a diameter substantially the same as the diameter of the cannula, said balloon in iniated condition having a radially extending surface facing the other end of said cannula forming a first contact area, a lumen independent of said cannula extending substantially the length of said cannula and passing through said connecting means and being on the opposite side of said balloon, said iirst area being spaced from said cannula and adapted to be spaced from the area of said perforation, cannula holding and constriction assembly means positioned on said cannula for axial movement along said cannula to impart tension to said cannula in order to maintain said tirst area tightly against said flesh and to constrict the passageway, said assembly means including a second contact area `facing said first area in order that pressure exerted by said second area towards said irst area embeds said first area into the iiesh around said perforation to effectively seal said perforation, and pressure maintaining means included in said assembly for maintaining pressure of said second area towards said first area.

6. A cannula for sealing a perforation in flesh that forms a cavity in a body and for releasably securing to said body, comprising: an elongated cannulahaving a passageway, an inflatable balloon surrounding one end of said cannula, connecting means securing said balloon to said cannula, said connecting means extending radially outwardly from said cannula to increase the effective pressure area of said balloon, said balloon in inflated condition having a radially extending surface facingthe other end of said cannula forming a 'first contact area, said lirst area being spaced from the cannula and adapted to be spaced from the edges of said perforation, means for liuid communication with said balloon, cannula holding and constriction assembly means positioned on said cannula for axial movement along said cannula to impart tension to said cannula in order to maintain said first area tightly against said lies-h and to constrict the passageway, said assembly means including a second contact area facing said first area in order that pressure exerted by said second area towards said first area embeds said rst area into the esh around said perforation to effectively seal said perforation, pressure maintaining means included in said assembly for maintaining pressure of said second area towards said first area, means for reducing the diameter of said passageway, said means for reducing including a resilient member slidably positioned withinsaid passageway and gripping means on the exterior of said cannula for gripping said resilient member through the wall of said cannula to reduce the effective diameter of the passageway and maintain the rst area embedded in the flesh and the cannula in tension.

i 7. A cannula for sealing a perforation in flesh that forms a cavity in a body and for releasably securing to said body, comprising: an elongated cannula having a passageway, an infiatable balloon surrounding one end of said cannula, connecting means securing said balloon to said cannula, said connecting means extending radially outwardly from said cannula to increase the effective pressure area of said balloon said balloon in inflated condition having a radially extending surface facing the other end of `said cannula forming a first contact area, said first area being spaced from the cannula and adapted to be spaced from the edges of said perforation, means for fluid communication with said balloon, cannula holding and constriction assembly means positioned on said cannula for axial movement along said cannula to impart tension to said cannula in order to maintain said first area tightly against said flesh and to constrict the passageway, said assembly means including a second contact area facing said first area in order that pressure exerted by said second area towards said first area embeds said first area into the flesh around said perfo-ration to effectively seal said perforation, pressure maintaining means included in said assembly for maintaining pressure of said second area .towards said first area, said assembly means including means for reducing the size of said passageway, said means for reducing including a resilient member slidably positioned within said passageway and gripping means on the exterior of said cannula for gripping said resilient member through the wall of said cannula to simultaneously reduce the effective diameter of the passageway and maintain the first area embedded in ythe flesh and the cannula in tension, one of said gripping means being positioned on opposite side of said resilient member from another of said gripping means for movement toward and away from said other gripping means and said resilient member.

8. An insertion device including a cannula for sealing a perforation in flesh that forms a cavity in a body and for releasably securing to said body, comprising: an elongated cannula having a passageway, an inflatable balloon surrounding one end of said cannula, connecting means securing said balloon to said cannula, said connecting means extending radially outwardly from said cannula to increase the effective pressure area of said balloon, said balloon in inflated condition having a -ra dially extending surface facing the other end of said cannula forming a first contact area, said first area being spaced from the cannula and adapted to be spaced from the edges of said perforation, means for fluid communication with said balloon, cannula holding and constriction assembly vmeans positioned on said cannula for axial movement along said cannula to impart tension to said cannula in order to maintain said rst area tightly against said flesh and to constrict the passageway, said assembly means including a second contact area facing said first area in order that pressure exerted by said second area towards said first area embeds said first area into the flesh around said perforation to effectively seal said perforation, pressure maintaining means included in said assembly for maintaining pressure of said second area towards said first area, and a tube within said cannula passing through said connecting mean-s, means for reducing the diameter of said passageway to retain said tube in position, said means for reducing including a resilient member slidably positioned within said passageway and gripping means on the exterior -of saidcannula for gripping said resilient member through the wall of said cannula to simultaneously reduce the effective diameter of the passageway and maintain the first area embedded in the flesh and the cannula'in tension, one of said gripping means being positioned on the opposite side of resilient member from another of said gripping means for movement toward and away from said Vother gripping means and said resilient member.

9. The construction of claim 8, wherein said second area includes a fiat fiange portion in contact alignment with ysaid first area.

10. An insertion device including a cannula for sealing a perforation in flesh that forms a cavity in a body and for releasably securing to said body,comprising: an elongated cannula having a passageway, an infiatable balloon surrounding one end of said cannula, connecting means securing said balloon to said cannula, said vballoon in inflated condition having a radially extending surface facing the other end of said cannula forming a first contact area, said first area being spaced from the cannula and adapted to be spaced from the edges of said perforation,said connecting means being a substantially flat disc extending outwardly from said cannula to increase the effective pressure area of said balloon, said disc being eccentrically positioned on said balloon and remote from said first contacted area to avoid contact to the flesh adjacent the perforation, a lumen independent of said cannula extending substantially the length of the cannula passing through said connecting means and secured to the opposite side of said balloon `to provide fiuid communication with said balloon, cannula holding means postioned on said cannula for axial movement along said cannula to impart tension to said cannula in order to maintain said first area tightly again-st said flesh, said assembly means including a second contact area facing said first area in order that pressure exerted by said second area towards said first area embeds said first area into the flesh around said perforation to effectively seal said perforation, pres- Isure maintaining meansincluded in said assembly for maintaining pressure of said second area towards said first area, a tube within said cannula passing through said connecting means, and said pressure maintaining means including gripping means frictionally engaging said cannula f-or holding said assembly in a predetermined position along said cannula.

References Cited by the Examiner UNITED STATES PATENTS 2,324,520 7/1943 Lamson 128-1 2,586,940 2/1952 Graham 12S-349 2,667,875 2/1954 Wallace 128-349 2,898,917 8/1959 Wallace 128-350 3,039,468 6/1962` Price 12S- 348 FOREIGN PATENTS 179,842 10/1954 Austria.

676,943 12/ 1929 France. 19,196 1906 Great Britain.

134,367 11/1919 Great Britain.

141,591 1/1961 Russia.

RICHARD A. GAUDET, Primary Examiner.

v DALTON L. TRULUCK, Assistant Examiner.

Claims (1)

1. A CANNULA FOR SEALING A PERFORMATION IN FLESH THAT FORMS A CAVITY IN A BODY AND FOR RELEASABLY SECURING TO SAID BODY COMPRISING: AN ELONGATED CANNULA HAVING A PASSAGEWAY, AN INFLATED BALLOON SURROUNDING ONE END OF SAID CANNULA, SEPARATE CONNECTING MEANS SECURED TO ONE END OF SAID CANNULA AND RADIALLY OUTWARDLY TO SAID BALLOON, SAID BALLOON BEING POSITIONED RADIALLY OUTWARDLY FROM SAID CANNULA AT THE POINT OF INTERSECTION OF THE BALLOON AND SAID CONNECTING MEANS, SAID SEPARATE CONNECTING MEANS BEING UNIFORMLY THINNER IN LONGITUDINAL CROSS SECTION THAN SAID BALLON WHEN SAID BALLOON IS INFLATED, SAID BALLOON IN INFLATED CONDITION HAVING A RADIALLY OUTWARDLY EXTENDING SURFACE FACING THE OTHER END OF SAID CANNULA FORMING A FIRST CONTACT AREA, A LUMEN EXTENDING SUBSTANTIALLY THE LENGTH OF THE CANNULA AND PASSING THROUGH AT LEAST A PORTION OF SAID CONNECTING MEANS AND SECURED SO AS TO BE IN FLUID COMMUNICATION WITH SAID BALLOON, SAID FIRST AREA BEING RADIALLY SPACED FROM SAID CANNULA AND ADAPTED TO BE SUBSTANTIALLY SPACED FROM THE EDGES OF SAID PERFORATION BY SAID SEPARATING MEANS SO AS TO PROVIDE A FIRM CONTACT BETWEEN THE BALLOON AND THE FLASH, CANNULA HOLDING MEANS POSITIONED ON SAID CANNULA FOR AXIAL MOVEMENT ALONG SAID CANNULAR TO IMPART TENSION TO SAID CANNULAR IN ORDER TO MAINTAIN SAID FIRST AREA TIGHTLY AGAINST SAID FLESH, SAID HOLDING MEANS INCLUDING A SECOND CONTACT AREA FACING SAID FIRST AREA IN ORDER THAN PRESSURE EXERTED BY SAID SECOND AREA TOWARDS FIRST AREA EMBEDS SAID FIRST AREA INTO THE FLESH AROUND BUT SUBSTANTIALLY SPACED FROM SAID PERFORATION TO EFFECTIVELY SEAL SAID PERFORATION FROM SAID CAVITY, AND PRESSURE MAINTAINING MEANS INCLUDED IN SAID HOLDING MEANS FOR MAINTAINING PRESSURE OF SAID SECOND AREA TOWARDS SAID FIRST AREA.

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