US3880137A

US3880137A - Two-piece implants

Info

Publication number: US3880137A
Application number: US464637A
Authority: US
Inventors: Louis Bucalo
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-02-12
Filing date: 1974-04-26
Publication date: 1975-04-29
Anticipated expiration: 1992-04-29

Abstract

An implant for a living being. A tubular organ such as a vas deferens is divided into a pair of separate portions having free ends adjacent each other. The implant has a pair of parts which are separately introduced into the lumens of the separate portions of the tubular organ while the parts of the implant remain accessible at the free ends of these separate portions of the tubular organ. These parts which are thus accessible are then joined together to render the implant operative without excessive stretching of the tubular organ so that excessive slack is not produced therein. The tubular organ may be a vas deferens while the implant is a vas valve capable of reversively blocking flow in the vas deferens and having the separate parts one of which is constituted by a tubular component and the other of which is constituted by the remainder of the vas valve, these parts being united after being introduced into the lumens to provide the assembled vas valve.

Description

United States Patent Bucalo Apr. 29, 1975 TWO-PIECE IMPLANTS Primary E.\aminerDalton L. Truluck [75] Inventor: Louis Bucalo, Holbrook, N.Y. Agent or Firm steinberg & Blake [73] Assignees: Louis Bucalo, Holbrook; Investors 57 ABSTRACT In Ventures, Inc., New York, both of NY.

[22] Filed: Apr. 26, I974 [21] Appl. No.: 464,637

Related US. Application Data [62] Division of Set. No. 3310i), Feb. l2, I973.

[52] US. Cl. 128/1 R; 128/334 C [5]] Int. Cl A6lb 19/00 [58] Field of Search.... l28/l R. 274, 303 R, 334 C; 3/1

[56] References Cited UNITED STATES PATENTS 3.613.6(1l lU/l97l Shah l28/l R 3,704,704 [2/1972 Gonzales... l28/l R 177L526 ll/l973 Rudic l28/334 C 3.820.528 6/1974 Rogers l28/l R has- An implant for a living being. A tubular organ such as a vas deferens is divided into a pair of separate portions having free ends adjacent each other. The implant has a pair of parts which are separately introduced into the lumens of the separate portions of the tubular organ while the parts of the implant remain accessible at the free ends of these separate portions of the tubular organ. These parts which are thus accessible are then joined together to render the implant operative without excessive stretching of the tubular organ so that excessive slack is not produced therein. The tubular organ may be a vas deferens while the implant is a vas valve capable of reversively blocking flow in the vas deferens and having the separate parts one of which is constituted by a tubular component and the other of which is constituted by the remainder of the vas valve, these parts being united after being introduced into the lumens to provide the assembled vas valve.

3 Claims, 10 Drawing Figures TWO-PIECE IMPLANTS CROSS REFERENCE TO RELATED APPLICATION The present application is a division of copending application Serv No. 332.019. filed Feb. I2. 1973 and entitled Two-Piece Implants and Implanting Methods."

BACKGROUND OF THE INVENTION The present invention relates to implants for living beings.

In particular. the present invention relates to implants which are designed to be received in the lumens of tubular organs.

When an implant such as a vas valve is to be introduced into the lumen of a tubular organ such as a vas deferens. it is customary to divide the tubular organ such as the vas deferens into a pair of separate portions which have free ends adjacent to each other. The surgeon will then introduce the implant. such as a vas valve. first into the lumen of one of the separate portions of the tubular organ and then into the lumen of the other of the separate portions of the tubular organ. Because the parts ofthe implant which are respectively received in these lumens olthe separate portions of the tubular organ are relatively long. it is necessary for the surgeon to stretch the tubular organ and distend it to an undesirable extent in order to be able to effectively introduce the implant into the lumens of the separate portions of the tubular organ. The result of these procedures is that a considerable amount of slack is introduced into the tubular organ resulting sometimes in prevention of reestablishment of flow when an implant such as a valve is placed in its open position.

A further problem which is encountered with an implant which is in the form of a valve is that it is cometimes difficult for the physician to know from the esterior of the valve when it is in its open position and when it is in its closed position.

In addition. when the implant is a valve. it sometimes happens that the openings at the opposed free ends of the valve become blocked by substances situated in the lumen of the vas deferens or the like. so that even when the valve is open to reestablish flow through the tubular organ. such flow cannot be reliably established.

In this latter connection. it sometimes happens that even during introduction ofthe implant into the lumen. substances in the lumen itself flow into the interior of the implant blocking the interior of the implant and preventing flow therethrough in an undesirable manner.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present inabove drawbacks.

In particular. it is an object of the present invention to provide an implant which will avoid the necessity of excessive distension of the tubular organ during intro duction of the implant into the lumen thereof.

A more specific object of the present invention is to provide an implant in the form of a vas valve which can be introduced into a tubular organ formed by a vas deferens in such a way that excessive distension of the latter will not be required.

It is also an object of the present invention to provide a vas valve which can be introduced into the vas deferens in a manner which will avoid blocking of the interior of the valve.

Furthermore. it is an object of the present invention to provide a vas valve which can reliably reestablish flow through the valve whenever desired even if it should happen that the outer free ends of the valve become blocked.

Yet another object of the present invention is to provide a vas valve which can be reliably placed without difliculty in open and closed positions.

Yet another object of the present invention is to provide a vas valve which will reliably prevent movement of sperm along the exterior of the valve so that only movement of sperm through the interior of the valve is assured when the valve is placed in an open position.

According to the method of the invention. the tubular organ which is to receive the implant is cut through so as to form a pair of portions having free ends situated adjacent each other. and then a two-part implant has its respective parts introduced separately into the lumens of the separate portions of the tubular organ with the two parts of the implant accessible at the free ends of these separate portions. These separate parts of the implant are then joined to each other so as to render the implant operative and so as to complete the assembly thereof. and through this expedient it becomes possible to introduce the implant without excessive distension of the tubular organ.

The implant of the invention includes a pair of components adapted to be separately introduced into the lumens of the separate portions of the tubular organ. and these components carry a means for connecting them to each other after they are respectively introduced into the lumens of the separate portions of the tubular organ so as to render the implant operative. Thus. in the specific case of a vas valve. the implant which is formed by the vas valve is composed of a pair of parts one of which includes a simple tubular part and the other of which includes the remainder of the vas valve. and these components carry a means such as male and female mating tapered portions which can be placed one in the other with a wedge fit so that they will remain assembled and render the implant operative after its separate components have been separately introduced into the lumens of the separate portions of the vas deferens.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. I is a longitudinal sectional elevation schemati cally illustrating a vas deferens with an implant of the invention situated therein;

FIG. 2 is an end view of the vas valve of FIG. I as seen from the right of FIG. 1;

FIG. 3 is a fragmentaty sectional elevation illustrating the connecting means carried by the separate components of the vas valve for connecting them to each other:

FIG. 4 is a fragmentary side elevation of one end re gion of the vas valve. the other end region having the same construction;

FIG. 5 is a transverse sectional elevation of the structure of FIG. 4 taken along line 55 of FIG. 4 in the direction of the arrows;

FIG. 6 is a schematic illustration of the introduction of an implant into a tubular organ.

FIG. 7 shows in elevation at mandrel to be used with one of the components of FIG. 1;

FIG. 8 is an illustration of another mandrel to be used with the other of the components of the vas valve of FIG. I;

FIG. 9 is a fragmentary side elevation of one end of the vas valve of FIG. I showing a further addition thereto; and

FIG. is a transverse section of the structure of FIG. 9 taken along line I0I0 of FIG. 9 in the direction of the arrows.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. I. the implant 10 of the invention is in the form of a vas valve in the illustrated example. This valve includes a pair of

parts

12 and 14. The part 12 is in the form of an elongated tube made of any suitable material which is compatible with the body. while the part 14 includes the rest of the vas valve. Thus. the part I4 includes the valve housing 16 carrying in its interior the rotary valve member whose stem is connected to the turnable element 18 at the exterior ofthe valve. This element 18 is turned for the purpose of opening and closing the valve. In addition. the part l4 includes the tubular element 20 which is integral with and extends to the right from the housing 16, as illustrated In FIG. I. This tubular part 20 may be located at the test side of the valve while the part 12 may be located at the urethral side.

The tubular part I2 is formed at the region of its free end which is distant from the part 14 with a longitudinally extending slot 22 extending completely across the tubular part 12 inwardly from the left free end thereof. as viewed in FIG. I. through the distance indicated in FIG. I. In the same way, the tubular part 20 is formed with an elongated slit 24 extending completely across the part 20 and inwardly from the right free end thereof through a distance such as that indicated at the right in FIG. I.

In addition. the part I2 terminates at its right end in a barrier flange 26 formed. as shown in FIG. 2. with four peripheral V-notches 28 displaced by 90 with respect to each other about the periphery of the flange 26 so as to promote the ingrowth of tissue into these notches and thus provide a secure lodging of the part I2 in the vas deferens which forms the tubular organ in the illustrated example.

A means is provided for fastening the

parts

12 and 14 to each other after they are respectively introduced into the lumens of the separate portions of vas deferens which are illustrated in FIG. 1. Thus. before the implant 10 is situated in the tubular organ. this organ is transversely cut through so as to be divided into a pair of separate portions. Thus it will be seen that the vas deferens illustrated in FIG. I includes the elongated left portion 30 and the elongated right portion 32. these portions respectively terminating in the free ends 34 and 36 which are adjacent each other. As may be seen from FIG. 6, after the vas deferens illustrated has been cut through. its

separate portions

30 and 32 need only be deflected to an extremely small extent so as to be capable of receiving the implant of the invention. The part 30 which is angularly positioned approximately as shown in FIG. 6 will separately receive the tubular part 12 of the vas valve, this part being first covered at its exterior with a filamentary material such as gold wire 38. This wire may be wound around the exterior of the tubular part 12 and may also take the form of a suitable braid. Thus. by way of the use of this filamentary material it is possible to promote the ingrowth of tissue into intimate contact with the exterior surface of the tubular part 12. so as to greatly reduce the possibility of travel of sperm along the exterior of the tubular component 12.

In the same way. with the separate portion 32 of the vas deferens situated somewhat as illustrated in FIG. 6. it is possible for the surgeon to introduce the other part 14 into the lumen of the separate portion 32. This part I4 also carries at the exterior of the tubular extension 20 the filamentary material 40 in the form a gold wire or braid which covers the exterior surface of the tubular portion 20, and it will be noted that this material is extended all the way up to the part of the housing I6 which engages the vas deferens. and the braid or wire 38 also extends all the way up to the part of the flange 26 which engages the vas deferens. Thus, the ingrowth of tissue will also be promoted into intimate contact with the exterior surface of the part 20 and the part of the housing I6 adjacent to the part 20 in order to reduce the possibility of travel of sperm along the exterior of the part 14.

These parts 12 and I4 of the implant carry a means 42 for interconnecting these parts with each other after they have been introduced into the lumens ofthe

separate portions

30 and 32 of the tubular organ. This connecting means 42 is shown in detail in FIG. 3. Thus in accordance with the illustrated example the tubular part 12 has at the region of the flange 26 a female component 44 which is hollow and tapered at its interior. while the part I4 has a mating male component 46 which has at its exterior a taper which matches that of the interior of the female component 44. Thus. with this construction after the two parts of the valve are respectively received in the lumens of the

separate portions

30 and 32. the male component 46 and the female component 44 of the connecting means 42 are joined together with the male part 46 received with a tight wedge lit in the female part 44, so that in this way the valve is rendered operative.

As a result of this feature the extent to which the tubular organ must be distended is greatly reduced so that there is very little if any slack which will produce undesirable curvature of the tubular organ preventing in some cases the desired reestablishment of flow through the tubular organ. Thus, by dividing the implant into two parts which are joined to each other after the parts are respectively received in the lumens of the separate portions of the tubular organ. it is possible to join these parts together in such a way that the extent to which the tubular organ must be stretched and displaced from its initial location is very greatly reduced.

According to a further feature of the invention, prior to introducing the part I2 into the lumen of the portion 30 of the vas deferens. the mandrel 48 shown in FIG. 7 is situated in the interior of and fills the longitudinal bore of the part 12 so that this bore will not become blocked by or receive any of the material within the portion 30 of the vas deferens. In the same way a second mandrel S0 is situated in and completely fills the tubular part 20 at the bore of the latter so that this bore cannot become blocked during introduction of the part 14 into the lumen of the separate portion 32 of the vas deferens. For this purpose it is to be noted that the part 18 is turned so as to situate the valve in its open position. and the mandrel 50 is long enough to extend through the bore of the rotary valve member as well as through the male part 46 of the connecting means and of course through the entire length of the tube all the way up to the right end of the latter.

In this connection it is to be noted that after completion of the implanting procedures even if it should happen that the free ends of the

tubular part

12 and 20 which are distant from each other become blocked. it will nevertheless he possible for the semen and other fluids to enter into the bores of the

tubular parts

12 and 20 through the slots 22. Thus. after the implant has been introduced into the tubular organ. the valve will. after a certain period of time. be turned to its closed position. For this purpose the rotary part I8 carries a cross pin 52 received in suitable slots of a rotary wrench 54 shown in phantom lines in FIG. 1. The part 18 fixedly carries a springy detent 56 capable of being received either in the recess 58. at the periphery of an upper flange ofthe housing 16. when the valve is in its open position as illustrated. or in a detent recess 60 displaced 90 from the recess 58. When the springy detent 56 is in the recess 60 the valve is closed. Thus by providing these detent recesses and the springy detent member 56 it is possible for the operator to reliably locate the valve either in its open or closed position without any difficulty.

It will he noted from FIGS. 7 and 8 that the mandrels 48 and 50 are respectively provided with handles 62 and 64. After the part 12 has been situated within the lumen of the separate portion of the vas deferens. the mandrel 48 is removed. and the handle 62 is provided to facilitate the introduction and removal of the mandrel 48 from the tubular part l2. In the same way. after the part 14 has been received in the lumen of the separate portion 32 of the vas deferens. the mandrel is removed. and the handle 64 facilitates the introduction and removal of the mandrel 50 from the part 14.

It is to be noted that the

slots

22 and 24 may be replaced by a series of lateral openings 66 illustrated in FIGS. 4 and 5. Thus. instead of longitudinally extending slots as illustrated in HO. 1. it is possible to provide the free ends of the valve each with a plurality ofopen ings 66 as shown in FIGS. 4 and 5 at the free end of the tubular part 20. and thus with this construction also if it should happen that the free end of the tubular extension becomes blocked nevertheless it will be possible for fluid to enter through the lateral openings 66. Thus. this construction of FIGS. 4 and 5 is also included at the left end portion ofthe part 12 instead of the slot 22, if desired. Therefore. either with the

slots

22 and 24 or with the lateral openings 66 it is possible when the valve is placed in its open position to reestablish flow through the tubular organ in a highly reliable manner even if it should happen that the free ends of the tubular organ becomes blocked.

Thus. the vas valve 10 will initially remain in its open position until a sufficient time has elapsed for the implant to become properly lodged in the tubular organ with ingrowth of tissue occurring and with no possible build up of pressure within the tubular organ. Then the valve may be placed in its closed position so as to block the flow. and thus reliably prevent conception. In this connection it is to be noted that the ingrowth of tissue at the filamentary material at the exterior of the valve greatly cuts down any possibility of travel of sperm along the exterior of the valve. This prevention of travel of sperm along the exterior of the valve is greatly enhanced by the presence of the barrier 26. However. if it should be desired at any future time to reestablish the flow of fluid through the vas deferens. the valve can be returned to its open position. and then by reason of the

slots

22 and 24 or the openings 66 a reliable reestablishment of flow is assured. Furthermore. because of the minimal distension of the tubular organ during the introduction ofthe implant. according to the method of the invention. utilizing a two-part implant which has its parts connected to each other after they are received in the tubular organ. as described above. there is no possibility of formation of loops or other undesirable configurations in the tubular organ resulting from undesirable slack therein. so that in this way also a reestablishment of flow is assured and the possibility of undesirable growths or the like which could result from such slack is also reliably avoided.

In order to further prevent blocking of the interior of the vas valve. further measures are taken in accordance with further features of the invention.

Thus. upon cutting through the vas to provide the separated

portions

30 and 32 shown in FIG. 6. it will be found that lumen is covered with a layer of mucosa. In accordance with a further feature of the present invention a suitable reamer which is not illustrated is introduced into the lumen of the portion 30 of the vas so as to remove from the inner surface the lining of mucosa at least through a length equal to that which will subsequently be occupied by the left portion of the valve as illustrated in FIG. I. The same operations are then performed with the right portion 32 of the vas deferens so that in the latter also the inner lining of mucosa is removed at least through a length sufficient to accommodate the right portion of the valve as illustrated in FIG. I. Thus. through this expedient of reaming out the mucosa linings along the lumen portions where the vas valve is to be accommodated there is a considerable reduction of possibility of blocking the valve passages during introduction of the valve into the lumen of the vas.

Furthermore. as is illustrated in FIGS. 4 and 5. according to a further feature of the invention the exterior surfaces of the valve at the region of its opposed ends is provided with a coating of plastic 70. Thus. FIGS. 4 and 5 illustrate that embodiment where the opposed ends are provided with the lateral openings 66 as described above. but the plastic coating of FIGS. 4 and 5 can also be utilized with the embodiment of FIG. I where the opposed ends of the valve are provided with the

slots

22 and 24. In the case of FIGS. 4 and 5 the openings 66 are not covered by the plastic layer 70. and of course with the embodiment of FIG. 1 the

slots

22 and 24 also would not be covered by the plastic coating. This plastic coating 70 which is deposited in any suitable way on the exterior surface of the valve at its opposed end regions as illustrated in FIGS. 4 and 5 has the property of bonding itself intimately to the exterior surface of the valve so that it will remain securely connected thereto. and in addition the plastic coating will prevent the vas from adhering at its lumen to the exterior surface of the valve at the end regions thereof which are provided with the plastic coating 70. This plastic coating may be made of any plastic which will not adhere to the inner surface of the vas dcferens. For

example Teflon may be used for the plastic layer 70 which will prevent the vas from adhering to the outer end regions of the valve so that in this way there is an assurance that the openings 66 will remain free and clear to function properly whenever it is desired to reestablish fluid flow. Of course the same results will be achieved when the plastic coating is provided with the embodiment of FIG. 1. While Teflon has been men tioned above. it is of course possible to use any other plastic which is compatible with the human body and which has the property of preventing the vas front adhering to the surface of the plastic.

A further expedient for achieving results similar to those achieved with the embodiment of FIGS. 4 and 5 is illustrated in FIGS. 9 and I0. Thus. referring to FIGS. 9 and II) it will be seen that the end of the valve which has the slot 24 has deposited thereon elongated and circumferential beads 72. These beads 72 are made of a metal which is different from the metal used for the valve. The longitudinal and circumferential beads 72 are deposited in any suitable way on the elongated free end portion of the valve which is provided with the slot 24 shown in FIGS. 9 and 10, and of course the opposed elongated end region of the valve which is provided with slot 22 is also provided with these beads of metal 72. The beads of metal 72 are made of any metal which is different from the metal used for the valve. For cs ample if the elongated end regions of the valve are made of gold. then the beads 72 may be made of plati num or nickel.

Of course. this deposition of beads of a dissimilar metal on the exterior surface of the end regions of the valve can also be used with the embodiment of FIGS. 4 and 5. in which case the heads will not close any of the openings 66. It will be noted that the beads do not close the

slots

22 or 24.

As a result of the presence of the dissimilar metals there is an automatic generation of microvoltages which have the effect also of preventing adherence of the vas to the regions of the valve where the dissimilar metals are located. Therefore by depositing on the end regions of the valve beads 72 ofa metal different from the metal on which the beads are deposited there is an automatic creation of microvoltages which will reliably prevent adhering of the vas to the end regions of the valve. It is to be noted that the beads 72 are shown at a considerable distance from each other in FIGS. 9 and [0 for the sake of clarity. Actually the network oflongitudinal and circumferential beads will be denser than illustrated in FIGS. 9 and 10.

Therefore. by way of these expedients it is possible on the one hand to prevent the vas from adhering to the end regions of the valve and on the other hand by reaming out the interior mucosa linings initial blocking of the valve during introduction of the latter into the lumen is also reliably prevented.

What is claimed is:

I. An implant to be introduced into a tubular organ of a living being after the tubular organ has been divided into a pair of separate portions having free ends situated adjacent each other. said implant comprising a pair of parts one of which is to be introduced into the lumen of one of the separate portions and the other of which is to be introduced into the lumen of the other of the separate portions of the tubular organ. said parts remaining accessible at free ends of said separate portions of the tubular organ. and means operatively connected with said parts of the implant for connecting them to each other at the region of the free ends of the separate portions of the tubular organ for operatively connecting said parts of said implant to each other and render the implant operative after the parts thereof have been separately implanted. the tubular organ being a vas deferens and the implant being a vas valve. and said parts being respectively constituted by a tubular component which forms one of the parts and the remainder of the vas valve. said means for connecting said parts to each other including male and female tapered mating portions of said parts which fit together with a tight wedge fit. said one part of said vas valve being an elongated tubular component having a female portion of said means and terminating at said female portion of said means in an outwardly directed flange which forms a barrier.

2. The combination of claim I and wherein said barrier is formed with openings passing therethrough.

3. An implant to be introduced into a tubular organ of a living being after the tubular organ has been divided into a pair of separate portions having free ends situated adjacent each other. said implant comprising a pair of parts one of which is to be introduced into the lumen of one of the separate portions and the other of which is to be introduced into the lumen of the other of the separate portions of the tubular organ, said parts remaining accessible at free ends of said separate portions of the tubular organ. and means operatively connected with said parts of the implant for connecting them to each other at the region of the free ends of the separate portions of the tubular organ for operatively connecting said parts of said implant to each other and render the implant operative after the parts thereof have been separately implanted. the tubular organ being a vas deferens and the implant being a vas valve. and said parts being respectively constituted by a tubular component which forms one of the parts and the remainder of the vas valve. said means for connecting said parts to each other including male and female tapered mating portions of said parts which fit together with a tight wedge fit. said parts being respectively formed with bores extending along the entire length of said parts. and a pair of mandrels to be situated in said bores filling the latter during introduction of said parts into lumens of the separate portions of the vas deferens. to prevent blocking of said bores during introduction of the parts into the lumens. respectively. so that after the parts are thus introduced into the lumens said mandrels may be removed to provide unobstructed bores in said parts of said valve.

Claims

1. An implant to be introduced into a tubular organ of a living being after the tubular organ has been divided into a pair of separate portions having free ends situated adjacent each other, said implant comprising a pair of parts one of which is to be introduced into the lumen of one of the separate portions and the other of which is to be introduced into the lumen of the other of the separate portions of the tubular organ, said parts remaining accessible at free ends of said separate portions of the tubular organ, and means operatively connected with said parts of the implant for connecting them to each other at the region of the free ends of the separate portions of the tubular organ for operatively connecting said parts of said implant to each other and render the implant operative after the parts thereof have been separately implanted, the tubular organ being a vas deferens and the implant being a vas valve, and said parts being respectively constituted by a tubular component which forms one of the parts and the remainder of the vas valve, said means for connecting said parts to each other including male and female tapered mating portions of said parts which fit together with a tight wedge fit, said one part of said vas valve being an elongated tubular component having a female portion of said means and terminating at said female portion of said means in an outwardly directed flange which forms a barrier.

2. The combination of claim 1 and wherein said barrier is formed with openings passing therethrough.

3. An implant to be introduced into a tubular organ of a living being after the tubular organ has been divided into a pair of separate portions having free ends situated adjacent each other, said implant comprising a pair of parts one of which is to be introduced into the lumen of one of the separate portions and the other of which is to be introduced into the lumen of the other of the separate portions of the tubular organ, said parts remaining accessible at free ends of said separate portions of the tubular organ, and means operatively connected with said parts of the implant for connecting them to each other at the region of the free ends of the separate portions of the tubular organ for operatively connecting said parts of said implant to each other and render the implant operative after the parts thereof have been separately implanted, the tubular organ being a vas deferens and the implant being a vas valve, and said parts being respectively constituted by a tubular component which forms one of the parts and the remainder of the vas valve, said means for connecting said parts to each other including male and female tapered mating portions of said parts which fit together with a tight wedge fit, said parts being respectively formed with bores extending along the entire length of said parts, and a pair of mandrels to be situated in said bores filling the latter during introduction of said parts into lumens oF the separate portions of the vas deferens, to prevent blocking of said bores during introduction of the parts into the lumens, respectively, so that after the parts are thus introduced into the lumens said mandrels may be removed to provide unobstructed bores in said parts of said valve.