- Email: [email protected]
Ivalon Cystoplasty
THE JOURNAL OF UROLOGY
Vol. 88, No. 4 Oetober 1962 Copyright © 1962 by The Williams & Wilkins Co. Printed in U.S.A.
IVALON CYSTOPLASTY JAMES H. McDONALD
AND
ENGIN DENIZ
From the Department of Surgery, Division of Urology, University of Illinois College of Medicine and the Presbyterian St. Luke's Hospital, Chicago, Ill.
Polyvinyl-alcohol sponge (ivalon *) is a material which may be particularly valuable for use as a prosthetic device because of its tissue acceptability. The ready molding into the desired forms and the prompt invasion of the sponge interstices by host tissues enhance its possible use in altering existing organ defects. 1 Kudish 2 used this material as a patch replacement of excised segments of the vesical wall. His study was complicated by consistent extrusion of the sponge implant into the vesical lumen, urine leakage, and peritonitis. We have attempted to devise a method of cystoplasty, using the ivakm sponge, which would increase the vesical capacity, prevent urine leakage at the anastomosis, and serve as a tissueacceptable scaffold for regeneration of the vesical wall.
bladder lumen a circumferential excision of the bladder wall beneath the prosthesis was performed. The cystotomy was closed with 4-0 chromic catgut and the abdomen closed without drainage. Three animals failed to survive; two due to no apparent cause, and one from eviseration. Of the remaining 9 animals, two were au-
METHODS AND MATERIALS
A total of 33 male and female mongrel dogs were divided into 4 groups to examine varied applications of the use of the ivalon prosthesis. Group 1, 12 dogs. The ivalon sponge 5 mm. in thickness was moistened and molded over a 50 cc glass beaker with avoidance of excessive compression of the sponge. Sterilization was accomplished by boiling for 30 minutes producing a sponge shrinkage of 20 per cent. Under intravenous nembutal anesthesia, the bladder was exposed and the molded prosthesis sutured to the serosa of the dome of the bladder with continuous 4-0 chromic catgut. The abdomen was closed without drainage. One month later the bladder and prosthesis were re-exposed (fig. 1). A cystotomy was done anterior to the prosthesis and from within the Accepted for publication December 5, 1961. Read at annual meeting of North Central Section of American Urological Association, Inc., Cincinnati, Ohio, Sept. 27-30, 1961. * Ivalon is a polyvinyl-alcohol sponge distributed by Clay-Adams, Inc. 1 Boucek, R. J. and Noble, N. L.: Connective tissue: a technique for its isolation and study. A.M.A. Arch. Path., 59: 553, 1955. 2 Kudish, H. G.: The use of polyvinyl sponge for experimental cystoplasty. J. Urol., 78: 232, 1957. 511
Fm. 1. Group 1. Gross specimen 1 month after prosthesis implanted on bladder serosa shows integrity of anastomosis and wrinkling of prosthesis. topsied 1 month after the first operation, and seven were autopsied from 2 to 6 months following the second operation. Group 2, 12 dogs. The i valon sponge was formed and sterilized as in group 1 except for the use of a mold of 200 cc capacity before sterilization shrinkage. The first operation was identical to that in group 1. However, 1 month later cystotomy was done through a linear incision in the prosthesis with the bladder wall beneath the prosthesis ex-
512
J. H. MCDONALD AXD E. DENIZ
FIG. 2. Group 4. Gross specimen, 1 month after implantation of prosthesis containing balloon on bladder serosa. A, larged domed prosthesis. B, sagittal section shows absence of wrinkling or collapse of prosthesis with balloon in prosthetic cavity.
Fra. 3. Group 1. Small ivalon pouch. A, gross specimen at 3 months. B, photomicrograph (X2) of A shows complete regeneration of muscle lining ivalon prosthesis.
IV.\LOX CYSTOPLASTY
cisccl circumferentially. The 1n,s closed with continuous 4-0 ehromic catgut, anrl the abdomen was closed \\·ithout drainage. j.JJ animals sun·ived, and autopsies were performed at 3, 6, and 8 months following the Sl'concl operation. Group 8, 4 dogs. Under intrnvenous ncmbutal anesthesia a pre-cut ivalon sponge (10 b:· 1.5 by 0.5 cm.) was placed in the subcutaneous tissues overlaying the rrctus fascia. The abdominal incision was closed in 2 layers. Ont' month later the sponge implant 1Yas remon'd and placed in saline solution, while exposure aucl resection of approximately 50 per crnt of the liladc!Pr m'.re carried out. The sponge 1Yas then attached to the bladder wall by an innE'r continuous .J-0 chromic catgut including mucosa and sponge, aml an outer layer of continuous 4-0 chromic catgut including serosa, nmscle, and spongE'. Threl' animals fai!E'd to surtwo 1vithout apparent rause and one 1Yith urine leakage and peritonitis. The rl'maining animal was autopsied 6 months follm1·ing tlw seroncl operation. Group 4, 5 dogs. The animals and thP i,·alon pro~thesis were prepared as in gronp 2. In acldi-
tion, a latex finger-cot 1rns inffatrd wit!t 40 water and left within the prosthesis after the· first operation. This was clone in the hope of \HT· Yenting folding of the iYalon sponge (fig. 2). the sec:ond operation, the inflated fing<'r-cot w:1,,; removed in performing the c,rntotomy as in group 2. One animal failed to survi,·c'., without apparent cause, the remaining four were autopsied at :cl and 6 months follmYing the second operation. The blacklers and prostlwses 11-ere rl'mo,-cd ir: total at autopsy; the uretern ancl kiclnr_n; iu ali instances were grossly normal. The bladdcrn fixed in 10 per cent nentrnl formalin, bisected in thr median sagittal plane, photographed, an11 total sagittal sections treated with hernotoxv]m and Posin aml Yan Giesen stains. REc,ULTS
Group 1, small ivalon vo11ch. ln all specimen~ 2 through G months, there \\·as gros~ and contracturr of the prosthesis. On had an open orifice betwePn the blaclcler pouch, though in fo·e the orifice \\·as ronstrirtPd. Three of the iYalon pmH·.hes were lined wifo
F1G. 4. Croup l, Small ivalon pouch. A, gross specimen c1t (i months with folding and contraeture nf prosthesis. B, photornierogr:1,ph ( X2) of .l, with muscle regeneration complete exeept for small fihrnu~
bridge nt apex.
514
J. H. McDONALD AND E. DENIZ
FIG. 5. Group 2. Large ivalon pouch. A, gross specimen at 3 months shows folding of prosthesis with thick wall of tissue lining cavity. B, photomicrograph (X2) of A shows complete muscle layer lining cavity of prosthesis.
FIG. 6. Group 2. Large ivalon pouch. A, gross specimen at 6 months, with folding of prosthesis. B, photomicrograph (X 2) of A, with muscle lining prosthesis except for small fibrous bridge.
IV,~LO'i CYSTOPLASTY
Fm. 7. Group 2. Large jvalon pouch. A, gross specimen at 8 months indicates tissue tolerance of iv:dou a,nd sturdy pouch development with wide orifice, B, photomicrogrnph (X2) of Ji shows nearly complete muscle lining of pol!ch
fibrous tissue and in part by epithelium 3, and .5 months), The sponge in all but one was infiltrated by connective tissue, Two specimens, one at 3 months (fig, 3) and one at 6 months, ,,howerl muscle regro,vth extending along the inner ,,-all of tbe pouch, the latter having a small fibrous briclg(: at the pouch apex (fig, 4), The muscle: were considerably thinner than in the bladder wall and were covernd by a thick fibrotic suhrrrncosa and a thin smooth epithelium. 2, large iva.lon pouc/1., In 12 specimens, tlwre wt1s commensurntely greater wrinkling of the prosthesis (,ltw to the larger size.) but with retention of greater ancl larger V(:sicomifice than iu group 1. ;\.t 3 mouths, 2 specimens shm,·ed complete regrowth of muscle ,vithin the pouch with the nmsclr covered by n thin, smooth epithelium (fig, :5). The sponge was well infiltrated b? rnnnective tissue, In one speci1rn,n, thC'r(' \Yas no muscle or epithelium regrm,·th, onlr intC'rrnittcnt infiltration of the sponge by connective tissue and numbers of inflammator,1· cdk At G months, 2 specimens showed rcgro,vth of nrnscle within the pouch, The growth 1,·as nearly complete in one (fig. G) aud in the other obstructed at the apex lw a portion of the i,·alon
,L
FrG. 8, Group Implant, ivnfon pouch, Gros,'i (j months shows marked calcificahm, of multiple folds of prosthesis 11·ith ulceration 01 vesical mueosa,
specimen at
sponge which was not infiltrated with fibrous tissue, Epithelial coverngr: was complete in the first specimen and only 2.5 per cent in thn Recond, One specimen reyealcd an irrnignificant attempt
516
J. H. MCDOKALD AND E. DENIZ
Fm. 9. Group 2. Balloc:m ivalo_n pouch. ~1, grc:iss specimen at 3 months shows absence of folding or contrac~ure of pouch, but with no lmmg of ep1thelrnm or muscle. B, gross specimen at 6 months with marked foldmg ~n? contracture of pouch, heavy calcification of inner wall and no evidence of epithelium of muscle lmmg. '
at muscle regrowth, the pouch being lined in part by fibrous tissue and with partial epithelization. There were large collections of inflammatory cells in the portions of ivalon not lined by connective tissue or epithelium. Of 6 specimens at 8 months, five had complete or nearly complete muscle regrowth (3 with a small fibrous bridge) within the pouch. Epithelium lined the entire pouch in each specimen (fig. 7). One specimen grossly showed a narrowed orifice, purulent exudate over the inner surface of the pouch, and was without epithelization, muscle, or fibrous tisrne regrmvth within the pouch cavity. Group 3, implant ivalon pouch. One specimen at 6 months had calcification of the lumen surface of the ivalon pouch with marked cystitis and mucosa] ulceration (fig. 8). There was neither muscle, epithelium, nor fibrous tissue lining the pouch. Much of the sponge interstices contained inflammatory cells rather than connective tissue. Group 4, balloon ivalon pouch. Two of the 4 clogs were autopsied at 3 months and two were autopsied at 6 months. There v,as no wrinkling or contracture of the pouch at 3 months (fig. 9, A), but wrinkling and contracture at 6 months reduced the capacity to one-third that of the 3month spPcimen (fig. 9, B). Thrre was no evidence of regrowth of muscle or epithelium in anv of these pouches. Jn one 6-month specimen, there
was heavy ealcificatimi. of the luminal surface of the pouch. DISCUSSION
A number of problems developed in the course of this work with each subsequent group in the study being an attempt to overcome certain aspects of the difficulties encountered.. In group 1, the small size of the definitive ivalon pouch, with its attendant folding and the constriction of the vesico-prosthetic orifice, rendered. its use impractical. Consequently, in group 2, a pouch of four times greater capacity was used. This allowed an over-all greater pouch size than in group 1 and a much more adequate vesicoprosthetic orifice. However, there was marked folding of this larger prosthesis and a commensurate volume decrease greater than with the smaller pouch. Preliminary subcutaneous implantation of the ivalon sponge with subsequent direct anastomosis of the sponge in pouch form to the open bladder wall, though used in only a few instances, offered nothing in way of superior tissue regrowth and only added to the operative and postoperative problems. The use of the balloon ivalon pouch was elating since we found no evidence of folding or contracture of the pouch, at the time of cystotomy or 3 months postoperatively. Howew.r, the 6-month
517
IVALON CYSTOPLASTY
specimen showed such contracture and pouch cavity calcification as to temper any undue enthusiasm. The use of this technique in a larger series of animals, possibly with a polyvinyl balloon or solid globular body and antibacterial therapy, might lead to considerable improvement in results. Evidence of connective tissue infiltration of the sponge was present in all specimens. However, in some sponges, inflammatory cell accumulations overshadowed the connective tissue. This was particularly evident in those specimens in which there was absence of living growth of fibrous tissue, muscle, and epithelium. What part this has in the lack of muscle regeneration in these pouches and what benefit antibacterial therapy might have been, remains unanswered. There was unequivocal regeneration of bladder epithelium and muscle in certain of these pouches, being present at 4 and 6 months in the small
pouches and very nearly constant at 3, 6, and 8 months in the large pouches. However, such muscle regrowth is, in general, in a considerably thinner layer than that of the bladder. There has not been any demonstration of the physiological activity of these muscle-lined pouches. However, the operative feasibility, the considerable augmentation of bladder capacity, the adequate vesico-prosthetic orifice, and epithelial and muscle regeneration, as seen in the large volume prostheses, are noteworthy. SUMMARY
Augmentation of the vesical capacity in the dog has been accomplished by use of an ivalon prosthesis. Muscle regeneration and the maintenance of an adequate 'vesico-prosthetic' orifice has been reasonably consistent with the use of a large capacity ivalon pouch.
Vol. 88, No. 4 Oetober 1962 Copyright © 1962 by The Williams & Wilkins Co. Printed in U.S.A.
IVALON CYSTOPLASTY JAMES H. McDONALD
AND
ENGIN DENIZ
From the Department of Surgery, Division of Urology, University of Illinois College of Medicine and the Presbyterian St. Luke's Hospital, Chicago, Ill.
Polyvinyl-alcohol sponge (ivalon *) is a material which may be particularly valuable for use as a prosthetic device because of its tissue acceptability. The ready molding into the desired forms and the prompt invasion of the sponge interstices by host tissues enhance its possible use in altering existing organ defects. 1 Kudish 2 used this material as a patch replacement of excised segments of the vesical wall. His study was complicated by consistent extrusion of the sponge implant into the vesical lumen, urine leakage, and peritonitis. We have attempted to devise a method of cystoplasty, using the ivakm sponge, which would increase the vesical capacity, prevent urine leakage at the anastomosis, and serve as a tissueacceptable scaffold for regeneration of the vesical wall.
bladder lumen a circumferential excision of the bladder wall beneath the prosthesis was performed. The cystotomy was closed with 4-0 chromic catgut and the abdomen closed without drainage. Three animals failed to survive; two due to no apparent cause, and one from eviseration. Of the remaining 9 animals, two were au-
METHODS AND MATERIALS
A total of 33 male and female mongrel dogs were divided into 4 groups to examine varied applications of the use of the ivalon prosthesis. Group 1, 12 dogs. The ivalon sponge 5 mm. in thickness was moistened and molded over a 50 cc glass beaker with avoidance of excessive compression of the sponge. Sterilization was accomplished by boiling for 30 minutes producing a sponge shrinkage of 20 per cent. Under intravenous nembutal anesthesia, the bladder was exposed and the molded prosthesis sutured to the serosa of the dome of the bladder with continuous 4-0 chromic catgut. The abdomen was closed without drainage. One month later the bladder and prosthesis were re-exposed (fig. 1). A cystotomy was done anterior to the prosthesis and from within the Accepted for publication December 5, 1961. Read at annual meeting of North Central Section of American Urological Association, Inc., Cincinnati, Ohio, Sept. 27-30, 1961. * Ivalon is a polyvinyl-alcohol sponge distributed by Clay-Adams, Inc. 1 Boucek, R. J. and Noble, N. L.: Connective tissue: a technique for its isolation and study. A.M.A. Arch. Path., 59: 553, 1955. 2 Kudish, H. G.: The use of polyvinyl sponge for experimental cystoplasty. J. Urol., 78: 232, 1957. 511
Fm. 1. Group 1. Gross specimen 1 month after prosthesis implanted on bladder serosa shows integrity of anastomosis and wrinkling of prosthesis. topsied 1 month after the first operation, and seven were autopsied from 2 to 6 months following the second operation. Group 2, 12 dogs. The i valon sponge was formed and sterilized as in group 1 except for the use of a mold of 200 cc capacity before sterilization shrinkage. The first operation was identical to that in group 1. However, 1 month later cystotomy was done through a linear incision in the prosthesis with the bladder wall beneath the prosthesis ex-
512
J. H. MCDONALD AXD E. DENIZ
FIG. 2. Group 4. Gross specimen, 1 month after implantation of prosthesis containing balloon on bladder serosa. A, larged domed prosthesis. B, sagittal section shows absence of wrinkling or collapse of prosthesis with balloon in prosthetic cavity.
Fra. 3. Group 1. Small ivalon pouch. A, gross specimen at 3 months. B, photomicrograph (X2) of A shows complete regeneration of muscle lining ivalon prosthesis.
IV.\LOX CYSTOPLASTY
cisccl circumferentially. The 1n,s closed with continuous 4-0 ehromic catgut, anrl the abdomen was closed \\·ithout drainage. j.JJ animals sun·ived, and autopsies were performed at 3, 6, and 8 months following the Sl'concl operation. Group 8, 4 dogs. Under intrnvenous ncmbutal anesthesia a pre-cut ivalon sponge (10 b:· 1.5 by 0.5 cm.) was placed in the subcutaneous tissues overlaying the rrctus fascia. The abdominal incision was closed in 2 layers. Ont' month later the sponge implant 1Yas remon'd and placed in saline solution, while exposure aucl resection of approximately 50 per crnt of the liladc!Pr m'.re carried out. The sponge 1Yas then attached to the bladder wall by an innE'r continuous .J-0 chromic catgut including mucosa and sponge, aml an outer layer of continuous 4-0 chromic catgut including serosa, nmscle, and spongE'. Threl' animals fai!E'd to surtwo 1vithout apparent rause and one 1Yith urine leakage and peritonitis. The rl'maining animal was autopsied 6 months follm1·ing tlw seroncl operation. Group 4, 5 dogs. The animals and thP i,·alon pro~thesis were prepared as in gronp 2. In acldi-
tion, a latex finger-cot 1rns inffatrd wit!t 40 water and left within the prosthesis after the· first operation. This was clone in the hope of \HT· Yenting folding of the iYalon sponge (fig. 2). the sec:ond operation, the inflated fing<'r-cot w:1,,; removed in performing the c,rntotomy as in group 2. One animal failed to survi,·c'., without apparent cause, the remaining four were autopsied at :cl and 6 months follmYing the second operation. The blacklers and prostlwses 11-ere rl'mo,-cd ir: total at autopsy; the uretern ancl kiclnr_n; iu ali instances were grossly normal. The bladdcrn fixed in 10 per cent nentrnl formalin, bisected in thr median sagittal plane, photographed, an11 total sagittal sections treated with hernotoxv]m and Posin aml Yan Giesen stains. REc,ULTS
Group 1, small ivalon vo11ch. ln all specimen~ 2 through G months, there \\·as gros~ and contracturr of the prosthesis. On had an open orifice betwePn the blaclcler pouch, though in fo·e the orifice \\·as ronstrirtPd. Three of the iYalon pmH·.hes were lined wifo
F1G. 4. Croup l, Small ivalon pouch. A, gross specimen c1t (i months with folding and contraeture nf prosthesis. B, photornierogr:1,ph ( X2) of .l, with muscle regeneration complete exeept for small fihrnu~
bridge nt apex.
514
J. H. McDONALD AND E. DENIZ
FIG. 5. Group 2. Large ivalon pouch. A, gross specimen at 3 months shows folding of prosthesis with thick wall of tissue lining cavity. B, photomicrograph (X2) of A shows complete muscle layer lining cavity of prosthesis.
FIG. 6. Group 2. Large ivalon pouch. A, gross specimen at 6 months, with folding of prosthesis. B, photomicrograph (X 2) of A, with muscle lining prosthesis except for small fibrous bridge.
IV,~LO'i CYSTOPLASTY
Fm. 7. Group 2. Large jvalon pouch. A, gross specimen at 8 months indicates tissue tolerance of iv:dou a,nd sturdy pouch development with wide orifice, B, photomicrogrnph (X2) of Ji shows nearly complete muscle lining of pol!ch
fibrous tissue and in part by epithelium 3, and .5 months), The sponge in all but one was infiltrated by connective tissue, Two specimens, one at 3 months (fig, 3) and one at 6 months, ,,howerl muscle regro,vth extending along the inner ,,-all of tbe pouch, the latter having a small fibrous briclg(: at the pouch apex (fig, 4), The muscle: were considerably thinner than in the bladder wall and were covernd by a thick fibrotic suhrrrncosa and a thin smooth epithelium. 2, large iva.lon pouc/1., In 12 specimens, tlwre wt1s commensurntely greater wrinkling of the prosthesis (,ltw to the larger size.) but with retention of greater ancl larger V(:sicomifice than iu group 1. ;\.t 3 mouths, 2 specimens shm,·ed complete regrowth of muscle ,vithin the pouch with the nmsclr covered by n thin, smooth epithelium (fig, :5). The sponge was well infiltrated b? rnnnective tissue, In one speci1rn,n, thC'r(' \Yas no muscle or epithelium regrm,·th, onlr intC'rrnittcnt infiltration of the sponge by connective tissue and numbers of inflammator,1· cdk At G months, 2 specimens showed rcgro,vth of nrnscle within the pouch, The growth 1,·as nearly complete in one (fig. G) aud in the other obstructed at the apex lw a portion of the i,·alon
,L
FrG. 8, Group Implant, ivnfon pouch, Gros,'i (j months shows marked calcificahm, of multiple folds of prosthesis 11·ith ulceration 01 vesical mueosa,
specimen at
sponge which was not infiltrated with fibrous tissue, Epithelial coverngr: was complete in the first specimen and only 2.5 per cent in thn Recond, One specimen reyealcd an irrnignificant attempt
516
J. H. MCDOKALD AND E. DENIZ
Fm. 9. Group 2. Balloc:m ivalo_n pouch. ~1, grc:iss specimen at 3 months shows absence of folding or contrac~ure of pouch, but with no lmmg of ep1thelrnm or muscle. B, gross specimen at 6 months with marked foldmg ~n? contracture of pouch, heavy calcification of inner wall and no evidence of epithelium of muscle lmmg. '
at muscle regrowth, the pouch being lined in part by fibrous tissue and with partial epithelization. There were large collections of inflammatory cells in the portions of ivalon not lined by connective tissue or epithelium. Of 6 specimens at 8 months, five had complete or nearly complete muscle regrowth (3 with a small fibrous bridge) within the pouch. Epithelium lined the entire pouch in each specimen (fig. 7). One specimen grossly showed a narrowed orifice, purulent exudate over the inner surface of the pouch, and was without epithelization, muscle, or fibrous tisrne regrmvth within the pouch cavity. Group 3, implant ivalon pouch. One specimen at 6 months had calcification of the lumen surface of the ivalon pouch with marked cystitis and mucosa] ulceration (fig. 8). There was neither muscle, epithelium, nor fibrous tissue lining the pouch. Much of the sponge interstices contained inflammatory cells rather than connective tissue. Group 4, balloon ivalon pouch. Two of the 4 clogs were autopsied at 3 months and two were autopsied at 6 months. There v,as no wrinkling or contracture of the pouch at 3 months (fig. 9, A), but wrinkling and contracture at 6 months reduced the capacity to one-third that of the 3month spPcimen (fig. 9, B). Thrre was no evidence of regrowth of muscle or epithelium in anv of these pouches. Jn one 6-month specimen, there
was heavy ealcificatimi. of the luminal surface of the pouch. DISCUSSION
A number of problems developed in the course of this work with each subsequent group in the study being an attempt to overcome certain aspects of the difficulties encountered.. In group 1, the small size of the definitive ivalon pouch, with its attendant folding and the constriction of the vesico-prosthetic orifice, rendered. its use impractical. Consequently, in group 2, a pouch of four times greater capacity was used. This allowed an over-all greater pouch size than in group 1 and a much more adequate vesicoprosthetic orifice. However, there was marked folding of this larger prosthesis and a commensurate volume decrease greater than with the smaller pouch. Preliminary subcutaneous implantation of the ivalon sponge with subsequent direct anastomosis of the sponge in pouch form to the open bladder wall, though used in only a few instances, offered nothing in way of superior tissue regrowth and only added to the operative and postoperative problems. The use of the balloon ivalon pouch was elating since we found no evidence of folding or contracture of the pouch, at the time of cystotomy or 3 months postoperatively. Howew.r, the 6-month
517
IVALON CYSTOPLASTY
specimen showed such contracture and pouch cavity calcification as to temper any undue enthusiasm. The use of this technique in a larger series of animals, possibly with a polyvinyl balloon or solid globular body and antibacterial therapy, might lead to considerable improvement in results. Evidence of connective tissue infiltration of the sponge was present in all specimens. However, in some sponges, inflammatory cell accumulations overshadowed the connective tissue. This was particularly evident in those specimens in which there was absence of living growth of fibrous tissue, muscle, and epithelium. What part this has in the lack of muscle regeneration in these pouches and what benefit antibacterial therapy might have been, remains unanswered. There was unequivocal regeneration of bladder epithelium and muscle in certain of these pouches, being present at 4 and 6 months in the small
pouches and very nearly constant at 3, 6, and 8 months in the large pouches. However, such muscle regrowth is, in general, in a considerably thinner layer than that of the bladder. There has not been any demonstration of the physiological activity of these muscle-lined pouches. However, the operative feasibility, the considerable augmentation of bladder capacity, the adequate vesico-prosthetic orifice, and epithelial and muscle regeneration, as seen in the large volume prostheses, are noteworthy. SUMMARY
Augmentation of the vesical capacity in the dog has been accomplished by use of an ivalon prosthesis. Muscle regeneration and the maintenance of an adequate 'vesico-prosthetic' orifice has been reasonably consistent with the use of a large capacity ivalon pouch.