PERITONEAL CATHETER

Abstract: A two-section implatable catheter (10) for peritoneal dialysis having a retainer section (11) which permanently ingrows into the abdominal wall and a catheter tube section (12). The two sections are normally connected together in a fluid-tight seal but may be separated to permit replacement of the tube section of an indwelling catheter without necessitating surgical removal of the retainer section.

Description: PERITONEAL CATHETER Background and Summary In peritoneal dialysis, dialysate is introduced into the peritoneal cavity through an indwelling catheter and, after a measured interval during which dialysis occurs within the patient with the peritoneal mem- _hrane serving as the diffusion membrane, is removed and discarded. Such a procedure has a number of advantages over conventional he odialysis, such as the elimination of intravenous connections, avoidance of the risks and complexities of external blood circulation, and the suitability of the procedure for patient self-treatment. In general, peritoneal dialysis- is gaining recognition as a relatively simple, safe, and inexpensive alterna¬ tive to hemodialysis. See K. M. Jones and P. Ivanovich, Peritoneal Dialysis - Treatment for End-Stage Diabetic Nephropathy, A Sect Proceedings, Vol. II, pp. 97-99 (1974). The indwelling catheter commonly used in peritoneal dialysis is per¬ forated at its distal end and is provided with at least one porous cuff of Dacron on other material suitable for tissue ingrowth and secured to the catheter tube at an intermediate location. The short proximal end portion of the catheter projects externally from the patient's abdominal wall and is adapted to be connected to conventional external dialysis equipment when a lavage procedure is to be undertaken. Such a catheter, although intended to be a permanent or at least a long-term implantation, may require surgical removal after only a few months of use should the lumen of the catheter become occluded by fibrin, or should the openings at the distal end become clogged or reduced to such an extent that, the rate of flow of dialysate becomes unacceptably low. Since such problems develop well after tissue ingrowth into the cuff (or cuffs) of the catheter has occurred, replacement of the ingrown occluded catheter requires an operating room procedure. Not only is such surgery bothersome and costly; it is also unpleasant both physically and psychologically for the patient. A main object of this invention therefore lies in providing a peritoneal catheter construction which substantially eliminates occlusion of the perforations and/or lumen of an indwelling catheter as a major problem in chronic peritoneal dialysis. More specifically, this invention is concerned with an improved indwelling catheter that may be replaced whe necessary, to overcome problems of catheter occlusion, without the nee for major surgery and without the physical and emotional disadvantage attending such surgery. In brief, the peritoneal catheter of this invention is formed in tw main sections which are normally connected together in fluid-tight rela tion .but which may be separated should occlusion of the catheter tak place. One of the sections, the retainer section, comprises a tubula sleeve equipped with an external porous fabric cuff for tissue ingrowth. The other section, the catheter tube section, normally extends through th bore of the retainer section and is releasably coupled thereto. Th catheter tube section is provided with a rigid tubular plug sealingl bonded thereto, the plug having an external annular recess and being re ceivable in the bore of the sleeve so that an inward annular projection o the sleeve is received within the recess to produce a snug fluid-tigh interfit between the parts. In the disclosed embodiment, the sleeve is resilient and i reinforced in the zone of the inward annular projection by multipl windings extending about the sleeve and concealed by the ingrowth ring o cuff. The tension of the winding may be varied according to the resilienc of the sleeve material, and the thickness of that material, to produce a effective seal and still provide a separable interconnection between th two sections of the catheter. Other features, advantages, and objects of the invention will becom apparent from the specification and drawings. Drawings Figure 1 is a perspective view of a peritoneal catheter embodying this invention. Figure 2 is a framentary longitudinal sectional view of th catheter with the sections in assembled condition. Figure 3 is a fragmentary longitudinal sectional view of th retainer section with the tube section removed therefrom. O PI Figure 4 is a generally horizontal sectional view illustrating the catheter extending through the abdominal wall of a patient. Figure 5 is a sectional view illustrating a variation of the sleeve and. cuff construction of the retainer section. Description of Preferred Embodiment Referring to the drawings, the numeral 10 generally designates a peritoneal catheter consisting essentially of two main sections, namely, a retainer section 11 and a catheter tube section 12. The tube section has 10 a perforated distal end 12a and a proximal end 12b suitable for connection to any standard peritoneal dialysis machines such as, for example, the Drake-Willock unit marketed by D.W.S. Inc., Portland, Oregon or the Physio-Control unit marketed by Physio-Control Corporation, Redmond, Washington. Such units are well known in the art and, since they are not ■l 5 part of the present invention and are disclosed in the aforementioned reference, further discussion of them is believed unnecessary herein. The catheter tube 12 includes a soft plastic tube 13 and a relatively rigid tubular plug member 14 externally secured to tube 13 at an inter¬ mediate point closer to the tube's proximal end. Tube 13, without plug 14, 2Q is substantially the same as the standard peritoneal catheter developed by H. Tenckhoff and H. Schechter, as disclosed in the aforementioned Jones- Ivanovich publication and in certain of the references cited therein. The tube 13 may be formed of any relatively soft elastomeric material which is non-irritating and generally compatible with body tissue. Silicone rubber 25 has been found particularly effective but other materials having similar properties may be used. In general, the material should have a durometer within the range of about 30 to 60 Shore A. The dimensions of the tube may vary considerably depending on the size of the patient and other factors but, in general, the length would normally fall within the range of about 2 Q 25 to 100 centimeters, the inside diameter within the range of about 2 to 5 millimeters, and the wall thickness within the range of approximately 0.5 to 1.0 millimeters. The tubular plug 14 is permanently secured to the tube 13 by a silicone adhesive 15 or by any other suitable means. As shown in Figures 1 35 and 2, the outer surface of the plug includes a tapered distal portion 15, a tapered proximal portion 17, and an intermediate annular recess o channel 18. The recess is arcuate when viewed in longitudinal section an is delimited by a pair of longitudinally-spaced ridges 19 and 20 whic define the largest outside cross sectional dimensions of the plug. It wil also be observed that the plug has annular end faces 21 and 22, resultin from the fact that the frusto-conical surfaces 16 and 17 have dimensions a their reduced ends which are still substantially larger than the outsid diameter of tube 13 and that the edges defining those end faces, as well a the edges defining the end faces of the tubular retainer 11, are rounded t avoid sharp edges and to allow smooth insertion and removal of the plug. The plug may be formed of any rigid and durable material that i tissue-compatible and is capable of being permanently secured to tube 13 A polycarbonate condensation product marketed under the designation Lexa has been found particularly effective, but other suitable materials havin similar properties may be used. Rigidity and strength are importan because the plug must be capable of withstanding the constrictive forc exerted by the retainer 11 to produce a fluid-tight bacterial barrie between the parts when they are assembled as shown in Figure 2. The retainer 11 includes a tubular sleeve 23 and a porous ring o cuff 24 for tissue ingrowth. In the illustration given, the sleeve i formed entirely of a resilient polymeric material such as, for example soft silicone rubber. When the sleeve is in an untensioned or undeforme state, its concentric outer and inner surfaces 23 and 23b may be generall cylindrical in configuration as shown. Thus, the- bore 25 defined by inne surface 23b is of substantially uniform diameter, that diameter being th same or only slightly greater than the outside diameter of plug 14 at th reduced ends thereof. Therefore, when the end-tapered plug is inserte into the bore of the sleeve, considerable outward deformation of th stretchable sleeve takes place. Means are provided to limit or control the extent of radial expansio of the intermediate portion of the sleeve, that is, the portion of th sleeve which extends about recess 18 when the plug is fully received withi the sleeve. In the embodiment illustrated, such means takes form of filamentary winding 26 disposed within an external channel 27 formed in th intermediate portion of the sleeve although it is believed apparent that relatively non-stretchable collar or band of metal or other suitabl material might be substituted for the winding. Where a winding is used the filament may be formed of Dacron or any other suitable material havin OJ.ΓP high tensile strength and may, if desired, be embedded in a matrix material such as, for example, a silicone cement. Such winding serves as a reinforcing element to limit the extent of a radial displacement of the intermediate portion of the sleeve when the plug is inserted. The material of the sleeve that would otherwise expand outwardly is urged axially or longitudinally as indicated by arrows 28 in Figure 2. The result is a fluid-tight seal between the opposing surfaces of the intermediate por¬ tions of the sleeve 23 and plug 14. When the plug is fully inserted within the sleeve, as depicted in Figure 2, it is believed apparent that the force necessary to extract the plug will progressively increase until the ridge 19 of the plug clears the intermediate portion of the sleeve. Similarly, further insertion of the plug would be met by increased resistance until ridge 20 advances distally beyond the sleeve's intermediate portion. Con¬ sequently, the plug resists uncoupling movement, the extent of such re- sistance depending largely on the tightness and mass of winding 26 and the respective dimensions of plug 14 and sleeve 23. The objective is to wind the filament 26 just tightly enough that the plug could not under any normal circumstances become accidentally disconnected from the sleeve while, at the same time, permitting such disconnection when replacement of the catheter tube 12 is desired. If the characteristics of the elastomer selected for sleeve 23 are such that the sleeve does not readily expand as the plug is inserted, the cylindrical shape of the inner surface of the sleeve may be modified to conform (when the sleeve is untensioned) at least partially to the conical shape of the plug, thereby reducing the forces required for plug insertion. The porous cuff 24 may be formed of a felt, foam, or multiple layers of any suitable material having sufficient porosity, strength, and tissue- compatibility to permit the ingrowth of tissue when the catheter is sur¬ gically implanted. A felt of Dacron or other appropriate material is shown in Figures 2 and 3, such material being adhesively secured to the outer surface of the sleeve 23 over winding 26. If desired, the same adhesive which serves as a matrix for winding 26 may also be used to join the sleeve and cuff. Figure 4 schematically depicts the catheter 10 in implanted condi- tion. It will be observed that the retainer 11 is located within a layer 29 of subcutaneous fat of the abdominal wall between peritoneal membrane 30 (and pre-peritoneal facia 30a) and the der is and epidermis 31 and 32. The distal end portion 12a of the catheter tube is disposed within the peritoneal cavity and the proximal end portion of that tube projects ex ternally from the abdominal wall. A surgical procedure is obviousl required in order to implant the catheter end and, following such implanta tion, tissue invades the ingrowth ring 24 to secure the catheter in place. Healing occurs in the inner and outer layers 30-32 about tube 13, althoug no ingrowth of tissue into the. smooth flexible tube is possible. Should replacement of the catheter tube 12 later become necessar because of proteinaceous occlusion of perforations and/or lumen of th catheter, such replacement may be readily achieved without disrupting o disturbing the connection between the body tissue and ingrowth ring 24. While a small external incision may be necessary in order to allow th tapered plug to be withdrawn from the sleeve and through dermis an epidermis 31 and 32, such an incision would only be a relatively simpl step involving far less discomfort and trauma to the patient than surgical removal of the entire catheter, including retainer 11. Following suc removal of the catheter tube 12, a new sterile catheter tube of matchin dimensions would be fitted into place for subsequent peritoneal dialysi of the patient. Figure 5 illustrates an alternate form of ingrowth ring that may b used in place of the ring shown and described in connection with Figures 1-4. Ring 124 is formed in a manner similar to the sewing rings o prosthetic heart valves, as disclosed generally in patents such as 3,466,671; 3,371,352, and 3,365,728. The ring is formed of a suitable fabric such as, for example, Dacron cloth, and is folded into channel 27 where it is held in place by winding 126. The winding therefore performs the dual functions of holding the ingrowth cuff in place within the channel and of limiting radial expansion of sleeve 23 in a manner already described. If desired, the interior of the cuff 124 may be occupied by a resilient foam pad 135 or, if desired, by multiple folds of cloth 124. While in the foregoing we have disclosed embodiments of the inven¬ tion in considerable detail for purposes of illustration, it will be under¬ stood by those skilled in the art that many of these details may be varied without departing from the spirit and scope of the invention.

Claims: The Claims 1. A peritoneal catheter including a tube section and a retainer section, said tube section comprising an elongated flexible plastic tube for delivering and withdrawing dialysate and a relatively rigid tubular plug secured to and extending about an intermediate portion of said tube, said plug having tapered longitudinal surfaces adjacent the ends thereof and having an annular recess between said tapered surfaces, said retainer section comprising a resilient sleeve having a bore for sealingly and releasably receiving said plug and having a porous tissue ingrowth ring secured to the outer surface of said sleeve, whereby, following a term of implantation of said catheter, said tube section may be removed from a patient for cleaning or replacement without necessitating removal of said retainer section and without disturbing the ingrowth of tissue into said ring. 2. The catheter of Claim 1 in which said sleeve has a bore of generally cylindrical configuration. 3. The catheter of Claim 2 in which said bore has a diameter approximating the outside diameter of said plug at the ends thereof. 4. The catheter of Claim 2 in which said sleeve is formed of silicone rubber. 5. The catheter of Claim 1 in which reinforcing means of limiting expandability extends about the portion of said sleeve receiving said annular recess of said plug when said tube section and said retainer section are fully assembled. 6. The catheter of Claim 5 in which said reinforcing means com- prises a filamentary winding. 7. The catheter of Claim 6 in which said winding also secures said ingrowth ring in place. 8. A peritoneal catheter including a tube section and a retainer section, said tube section comprising an elongated flexible plastic tube for delivering and withdrawing dialysate and a relatively rigid tubular plug secured to and extending about an intermediate portion of said tube, said plug having tapered longitudinal surfaces adjacent the end thereof and having an annular recess between said tapered surfaces, said retainer section comprising a resilient sleeve having a generally cylindrical bor for sealingly and releasably receiving said plug and having a porous tissu ingrowth ring secured to the outer surface of said sleeve, said sleev being provided with reinforcing means of limited expandability in th portion thereof extending about said annular recess of said plug when sai tube section and retainer section are fully assembled. 9. The catheter of Claim 8 in which said bore of said sleeve has diameter that approximates the outside diameter of said plug at the end thereof. 10. The catheter of Claim 9 in which said sleeve is formed o silicone rubber. 11. The catheter of Claim 8 in which said reinforcing means com¬ prises a filamentary winding extending about said sleeve. 12. The catheter of Claim 11 in which said winding also secures said ingrowth ring in place on said sleeve.

Inventors: BORSANYI A, IVANOVICH P, VAUGHAN U
Applicants: AMERICAN HOSPITAL SUPPLY CORP
Application year: 1980
Main classification: A61M1
IPC codes: A61M1