British Journal of Urology (1998), 82, 196–198

RE VI EW

Urinary bladder wall repair: what suture to use?K.M.I. PALDepartment of Surgery, Aga Khan University Hospital, Karachi, Pakistan

strength is decreased and they are absorbed in tissuesIntroductionthrough degradation by acid hydrolytic and collageno-lytic enzymes. To improve their tensile strength andAt present there are no clear guidelines as to the most

suitable suture material available for the closure of resistance to enzymatic digestion, the material is treatedwith aldehyde solution and chromium trioxide, produc-urinary bladder wall defects; the general tendency is to

use one of the synthetic absorbable suture materials. ing ‘chromic’ catgut. Despite rigorous quality control,these sutures tend to have a variable loss of tensileThe interior of the urinary bladder is encountered often

by any surgeon opening the abdomen routinely. The strength and absorption time.The synthetic absorbable sutures most commonly usedfluid nature of its contents, with a high concentration

of solutes, predisposes to both a susceptibility to infection at present are derived from a-polyesters. The polymersused for their construction are inherently rigid and thusand a propensity to form concretions, especially on

foreign bodies. can be used as monofilaments only in the finest gauge.For clinical use, the fine filaments have to be braided toIt is now accepted practice that only absorbable suture

material should be used to repair bladder wall defects, produce diCerent suture sizes. The first to be introducedwas polyglycolic acid (PGA, Dexon@), which was fol-although initial experimental evidence had suggested

that polypropylene (a monofilament nonabsorbable lowed by polyglactin 910 (Vicryl@). Monofilamentabsorbable suture such as polydioxanone (PD) has alsosuture) could be used in urological procedures [1–4]. Of

the absorbable sutures, the earliest available and most been developed. Synthetic absorbable sutures appear tobe chemically degraded by the nonenzymatic hydrolysisfrequently used until recently was chromic catgut. With

the introduction of a variety of synthetic absorbable of ester bonds; their loss of tensile strength and physicalstructure in tissues is more uniform and can be predictedsutures, much attention has been given to their use in

bladder surgery. more accurately.At present there is no simple answer to the choice of

which suture is best suited for bladder repair. An idealSutures used in bladder repairsuture should have good handling and knot-holding

properties, should induce no tissue reaction and be To define the best suture material for bladder repair, theabsorbable, but maintain its strength long enough for following areas were examined: (i) tissue/material inter-sound healing to take place. In addition, for the urinary action; (ii) gain in tissue strength through healing inbladder it should not be aCected by urinary constituents relation to the loss of tensile strength in the sutureor by infected urine, and should not be lithogenic. In material with time; (iii) changes in suture tensile strengthpractice, the issue of cost must also be addressed in this with time; (iv) changes in suture tensile strength ondefinition, for cost is increasingly important in providing contact with uninfected and infected urine; (v) thequality medical care. Indeed, currently it must be shown lithogenic potential of diCerent materials. Unfortunatelythat there is an objective clinical advantage of one most of the answers available relate to either laboratorytreatment methodology over another, rather than a conditions or animal models; whether results from theseperceived theoretical superiority. sources can be extrapolated to clinical settings in their

entirety is open to question.The inflammatory response to suture materials hasTypes of absorbable sutures

been of concern in all types of tissues. It is thought thatAbsorbable sutures are made from either collagen the more intense the inflammatory response, the slower(catgut) or synthetic polymers. In the former, the tensile the gain in wound strength because of the greater local

degradation of collagen. Catgut sutures have been shownto cause the greatest inflammatory response in severalAccepted for publication 12 February 1998

196 © 1998 British Journal of Urology

URINARY BLADDE R WALL REPAIR 197

tissues [5]. Studies have compared tissue inflammatory retained significant strength; bladder wall woundstrength is then >80% of the normal unwoundedresponse in the urinary bladder, for diCerent suture

types, in animal models. In rabbits, on microscopic wall [8].The ability of various suture materials to maintainexamination there was no diCerence in the inflammatory

reaction between 5/0 catgut, 5/0 PD and polypropylene their strength while exposed to sterile and infected urinehas been examined [15]. In sterile urine, PD lost its[6]. In rats, PD had the greatest inflammatory response

initially, although catgut, PD and polyglactin had a strength and became fragmented after 3–6 days; PGAgradually lost strength, losing 74% of its original strengthsimilar response at 6 months [7]. The clinical significance

of moderate diCerences in inflammatory response at the by 10 days. Catgut showed little change in its breakingstrength over the 10-day period. In acidic urine infectedmicroscopic level is debatable.

The urinary bladder is one of the weakest organs with Escherichia coli PD lost all its strength after 6–10days; PGA lost 72% of its original strength after 10 days.where unwounded wall strength is concerned, compar-

able with the colon [8]. On healing, it behaves diCerently Conversely, catgut had lost only 8% of its originalbreaking value. In alkaline urine infected with Proteusto other tissues, having a very rapid gain in wound

strength after approximation of the edges. The force spp, PD sutures disintegrated over 3 days; PGA suturesreacted similarly, with sutures completely dissolving byneeded for tissue disruption approaches that of

unwounded tissue 14–21 days after wounding in animal the second day. However, catgut showed a rise inbreaking strength during the first 24 h and had onlymodels [8].

An argument proposed for the use of synthetic lost 6% of its original strength after 10 days.Studies on the lithogenic properties of various sutureabsorbable sutures is the extended tissue support pro-

vided, for up to 3–4 weeks. Tissues with comparable materials have shown that lithogenesis is proportionalto the duration of absorption of the material. The highesttensile strength, e.g. colon and stomach, attain 50–70%

of normal tissue strength 120 days after the surgical incidence has been noted with nonabsorbable braidedsuture material; monofilament nonabsorbable suturesclosure of wall defects [8,9]. Unwounded tissues appar-

ently have an inherent strength many times more than have similar problems, confirmed in experimental andclinical settings [2,3,8]. The use of both these types hasthat needed for the normal physical stress of their

particular function, thus the argument about longer been discontinued for bladder repair.One of the major disadvantages of animal-based stud-support loses its force. Barham et al. [10] have shown

that only in irradiated bladder tissue is the healing ies has been the species-specific diCerences in lithogenicpotential for diCerent sutures [2]. In the rabbit, withwound strength statistically better with the use of syn-

thetic absorbable sutures. alkaline urine and very high susceptibility to stoneformation in experimental settings, the lowest incidenceThe loss of suture tensile strength with time is an

important and often reported issue; absorbable sutures of concretion was with chromic catgut, the highest withpolypropylene and intermediate with PD [6]. In anotherlose tensile strength predictably in tissues with time,

more so than the synthetic variety. The tissue disruption study conducted in the rat [7] the lithogenic potentialof all three materials was similar, although the urineforce for normal bladder is #400 g/cm [8]. The suture

breaking-strengths of 2/0 and 3/0 sutures, i.e. those was never alkaline. In dogs, none of the sutures testedled to stone formation [2].commonly used in bladder repair, are given in Table 1

[11–13]. These sutures all have breaking strengthsmany times the force required for disruption in normal Conclusiontissues. Sutures lose # 40% of their original strength onforming a secure knot, the latter being the weakest part Of the absorbable sutures, chromic catgut has been used

the longest and has stood the test of time. The synthetic[14]. After 2 weeks, all three types of absorbable sutureabsorbable sutures have some theoretical advantages

Table 1 Tensile strength (g) of standard dry sutures [11,12] and but there have been no studies on humans to date where15 days after implantation in the subcutaneous tissues of rabbit [13] these advantages have been shown to be clinically

significant. Laboratory experiments and studies on ani-Size (dry) Size (implanted) mals have given conflicting results and can be interpreted

either way, depending on personal bias. As to rec-Suture type 3/0 2/0 3/0 2/0ommending which suture to use in repair of the urinarybladder, it can be safely stated that currently there is noChromic catgut 3000 4454 272 545suture material that has been convincingly shown to bePolyglycolic acid 2772 4363 977 909

Polyglactin 910 NA 5331 NA 3245 better than chromic catgut in clinical trials. If no clinicaladvantage can be shown, then cost is increasingly

© 1998 British Journal of Urology 82, 196–198

198 K.M.I . PAL

8 Hastings JC, Van Winkle W Jr, Barker E, Hines D,significant. There is a considerable diCerence in the priceNichols W. The eCect of suture materials on healingof diCerent absorbable sutures: chromic catgut, polyglac-wounds of the bladder. Surg Gyn Obs 1975; 140: 933–7tin 910 and PD cost (per 12, in rupees) 225, 1200 and

9 Hastings JC, Winkle WV, Barker E, Hines D, Nichols W.2500, respectively, i.e. the polyglactin and PD cost 4.9ECect of suture materials on healing wounds of stomachand 10 times the catgut (prices from Ethicon Ltd,and colon. Surg Gyn Obs 1975; 140: 701–7

Pakistan). Thus, after reviewing the available evidence10 Barham RE, Butz GW, Ansell JS. Comparison of wound

it reasonably certain that there is no convincing evidence strength in normal, radiated and infected tissues closedfor discontinuing the use of chromic gut in the repair of with polyglycolic acid and chromic catgut sutures. Surgthe urinary bladder. Gyn Obs 1978; 146: 901–7

11 Katz AR, Turner RJ. Evaluation of tensile and absorptionproperties of polyglycolic acid sutures. Surg Gyn Obs 1970;

References 131: 701–161 Bartone FF, Stinson W. Reaction of the urinary tract to 12 Howes EL. Strength studies of polyglycolic acid versus

polypropylene sutures. Invest Urol 1976; 14: 44–6 catgut sutures of the same size. Surg Gyn Obs 1973;2 Kaminske JM, Katz AR, Woodward SC. Urinary bladder 137: 15–20

calculus formation on sutures in rabbits cats and dogs. 13 Craig PH, Williams JA, Davis KW et al. Biologic comparisonSurg Gyn Obs 1978; 146: 353–7 of polyglactin 910 and polyglycolic acid synthetic

3 Healey GB, Warren MM. Stone formation on polypropylene absorbable sutures. Surg Gyn Obs 1975; 141: 1–10suture. J Urol 1979; 121: 836–7 14 Rodeheaver GT, Thacker JG, Owen J, Strauss M,

4 Yudofsky SC, Scott FB. Urolithiasis on suture materials: its Masterson T, Edlich RF. Knotting and handling character-importance, pathogenesis and prophylaxis: an introduction istics of coated synthetic absorbable sutures. J Surg Resto the monofilament Teflon suture. J Urol 1969; 102: 1983; 35: 525–30745–9 15 El-Mahrouky A, McElhaney J, Bartone FF, King L. In vitro

5 Van Winkle W, Hastings JC. Considerations in the choice comparison of the properties of polydioxanone, polyglycolicof suture materials for various tissues. Surg Gyn Obs 1972; acid and catgut sutures in sterile and infected urine. J Urol135: 113–26 1987; 138: 913–5

6 Morris MC, Baquero A, Redovan E, Mahoney E, BannetAD. Urolithiasis on absorbable and non-absorbable suture

Authormaterials in the rabbit bladder. J Urol 1986; 135: 602–37 Stewart DW, BuBngton PJ, Wachsman J. Suture material K.M.I. Pal, FRCS, MSc, Department of Surgery, Aga Khan

University Hospital, Stadium Rd, PO Box 3500, Karachiin bladder surgery: a comparison of polydioxanone, polyg-lactin, and chromic catgut. J Urol 1990; 143: 1261–3 74800, Pakistan.

© 1998 British Journal of Urology 82, 196–198