THE URETERIC STENT
RUSSELL ET ALIl
THE USE OF THE URETERIC STENT JOHN M. RUSSELL’,STEPHEN J. CLARKE~ AND WILLIAMH. BOYCE3. Section of Urology, Bowman Gray School of Medicine of Wake Forest University, a n d North Carolina Baptist Hospital, Winston-Salem, N o r t h Carolina.
The use and placementof uretericstents either endoscopicelly or as part of an open procedure are outllned. The ureteric stent can replace the pyelostomy or nephrostomy tube and slgnlflcantly reduce the postoperatlve rnorbldity.
A PROPERLY positioned uretehc stent may act as a mould for tubular epithelial regrowth following ureteric surgery, and also provides excellent dependent drainage of the kidney allowing free passage of urine into the bladder. Others have documented the value of endoscopically placed indwelling ureteric stents in providing short or long term renal drainage; however, the place of the ureteric stent in association with open surgery on the urinary tract continues to be widely debated (Zimskind et alii 1967; Zimskind, 1971). Following renal and ureteric surgery, primary healing of the uroepithelium is a paramount aim, and factors which permit this are worthy of close scrutiny. We believe that the use of internal drainage and a meticulous surgical repair of the collecting system are the principal factors in achieving this aim. Historically surgeons have accepted leakage of urine as unavoidable following these procedures, but many believe that urinary extravasation is a contributory factor t o stricture f o r m a t i o n (Leininger, 1975). Extravasated sterile urine produces chemical intlammation and consequent cicatrization; in addition, urine is an excellent culture medium for bacterial organisms, and seepage of urine to the skin provides a portal for bacterial entry. The resultant infection will further promote scar formation and may disrupt the surgical repair, delay wound healing, and prolong I
3
M.B., B.S. (Melb.). Resident in Urology. M 8.. B S. (Melb.), Chief Resident in Urology Professor of Urology
Reprints’ William H. Boyce, M 0 , Professor of Urology, Bowman Gray
School of Medicine of Wake Forest University. Winstone-Salem. North Carolina. 27103, U.S A
AUST.N.Z. J. SURG.VOL. 48-No.3, JUNE,1978
the convalescent period (Boyce, 1971, 1975). We believe that ureteric stents help to minimize cicatrization and subsequent stricture formation by preventing urinary leakage and providing moulds for epithelial and smooth-muscle regrowth. Definition.- A major controversy in urological surgery has been “to stent or not tostent?” Even the terminology has caused some debate, perhaps due to confusion between the words splint and stent. Goodwin (1972) correctly pointed outthatasplint is something put outside a structure to keep it immobile, whereas a stent is a mould for internal fixation. We accept the definition that the term “stent” designates a device or mould, of any suitable material, used to hold a graft i n place or to provide support for tubular structures that are being anastomosed. Development.- The value of keeping urine within the urinary tract, where feasible, has long been recognized. Ureteric catheters have been used for decades, but the concept of the ureteric stent as a mould was first described by Davis (1943). The materials initially used were prone to produce tissue reaction, and consequently the use of the stents was not widely accepted. Since the development of silicone rubber (Silastic Dow-Corning Co.), which is non-reactive within the urinary tract, the vast majority of problems with ureteric stents have been overcome (Mangelson et alii, 1968). In addition, this material is flexible, will not degenerate, and can be autoclaved (Zimskind et alii, 1967; Zimskind 1971). We feel that the stent has replaced the pyelostomy and nephrostomy tube, since with good internal drainage postoperative proximal urinary diversion is now unnecessary. 327
THE URETERIC STENT
RUSSELL ET ALll
Materials- Currently a length of medical grade silicone rubber (Silastic) tubing is used to traverse the ureter between the renal pelvis and bladder. The tubing, in a variety of sizes, is available in 10-foot and 50-foot coils. It is cut to the length of a ureteric catheter and autoclaved. The most commonly used sizes are listed in Table 1. Usually several small sideholes are cut at the proximal end of the stent to facilitate pelvic drainage (Figures 1, 2).
ureteric catheter, a Silastic stent with several small side-holes cut in the proximal end, and cystoscopic foreign body forceps. The ureteric catheter, initially with guide wire in place, is well lubricated and the ureteric stent fitted over it so that ashort segment of the ureteric catheter protrudes. The stent and its guiding ureteric catheter are then passed into the renal pelvis. The position of the stent can be confirmed radiographically (by injection of some
FIGURE1: Ureteric stents: (A) Cook ureteric indwelling pigtail stent; (B) regular medical grade silicone rubber (Silastic) tubing cut to length; (C) Gibbons indwelling ureteric stent.
FIGURE2:
Loaded stent: The tipe of a regular Silastic stent loaded on to a 4 C h ureteric catheter. Note the side holes cut in the end of the stent.
Endoscopic Placement Thc situations in which endoscopic placement of a ureteric stent is indicated are summarized in Table 2. In addition to their use for decompression and drainage of the obstructed kidney, stents play a role in assessing the potential function of an obstructed kidney prior to definitive surgery. A clamped ureteric stent has also been successfully used on several occasions to tamponade unilateral renal pelvic bleeding. The required equipment for endoscopic placement is a panendoscope, a 4 CR olive-tip
328
contrast medium) or by free irrigation of the renal pelvis. The ureteric catheter is carefully removed from the stent. The stent may be pushed into the bladder with foreign body forceps or it may be brought to the outside and taped to a Foley urethral catheter. The disadvantage of leaving the stent protruding from the urethra is the risk of ascending infection, while its advantages include the accurate monitoring of urine output and stent function; the prevention of reflux; and the ease of removal. When the stent is left in the bladder, a urethral catheter is not inserted unless otherwise indicated. AUST.N.Z. J. SURG.Vo~.48-N0.3, JUNE,1978
RUSSELL ET ALll
THE URETERIC STENT
In the past many urologists have found long-term renal drainage with ureteric catheters or stents impractical because of technical difficulties including displacement and inconsistent drainage (Gibbons et alii, 1976). Recently several selfretaining stents have been developed. The Gibbons indwelling ureteric stent and the Cook* ureteric indwelling pigtail stent (Hepperlen and Mardis, 1976) both have self-retaining devices (Figure 1) and have been used with moderate success. The insertion of a Gibbons stent is a difficult exercise, and requires prior uretric dilatation. The side wings of the Gibbons stent prevent ejection from the ureter, and the lower flange prevents upward migration. A metal spring embedded in the wall of the stent renders it radio-opaque and prevents its collapse. In our experience the Cook polyethylene pigtail stent is more easily placed than the Gibbons stent, but its smaller sizeand lumen make it prone to obstruction. Both of these stents may be removed at a later date if required. As well as the recognized indications in Table 1, it is worth considering stenting the ureter when the risk of ureteric obstruction is high, as during radiotherapy for treatment of pelvic lymphoma or malignancy. TABLE1 Silastic Medical Grade Tubing
mm
Inches Intern. Dia.
Intern. Dia.
Inches Extern. Dia.
mm Extern. Dia.
0030 0062 0062 0078
076 157 157 198
0065 0095 0125 0125
165 241 318 3.18
Charriere Size
Tubing Passes through thinwalled gauge needle
73 96 96
11 8 8
Open Surgical Placement When the stent is inserted under direct visiion, it is again usual to use it over a 4 Ch ureteric catheter. It is our practice in stone surgery to insert the stent as early as feasible during the procedure. Once the stent is placed in the bladder with six to eight centimetres of surplus length to prevent retrograde migration the ureteric catheter is removed, and the correct position of the stent confirmed by free irrigation. The side holes are then cut in the proximal end of the stent, and it is positioned as desired in the pelvis or upper pole calyx (Harrison and Nordan, 1974; Harrison et alii, 1977). In critical situations the upper endof the stent may be fixed with an absorbable suture.(5/0 chromicized catgut). *
Cook Incorporated. Melbourne, Australia.
AUST. N.Z. J.
SURG.
VOL. 48-No. 3, JUNE,1978
TABLE2 Indications lor Stent Placement SHORT TERM A. Endoscopic Placement Hydronephrosis Pyonephrosis Urinary Fistula Ureteral spasm e.g. stone manipulation Preoperative positioning Postoperative repositioning B. Intraoperative Placement Pyelolithotomy Nephrolithotomy Pyeloplasty Ureterohthotomy Ureteroneocystostomy Ureteroenterostomy Ureteroureterotomy LONG TERM Endoscopic Placement Extramural malignant Ureteric obstruction Complete Incomplete Ureteric stricture Aetroperitoneal fibrosis Urinary fistula (malignant)
Stents are placed at operation during most procedures involving the ureter or pelvis (Table 2). An alternative distal placement of the ureteric stent, particularly in ureteroneocystostomy in young children and in renal transplantation, is to bring the stent to the surface with a suprapubic catheter. Stents are easily removed by grasping them through a panendoscope under local anesthesia, usually at about the seventh postoperative day. Many patients, particularly females, will pass their stents spontaneously, and they should be forewarned of this possibility. It is rare for the clinical situation to demand that a stent be replaced; however, i f necessary this can be done endoscopically. Associated Problems of Ureteral Stents Mechanical problems with stents do occur, but as the stent can be so easily removed, adjusted, or replaced endoscopically, the procedure is free of significant complications. Following most open procedures involving the uroepithelium it is usual to employ a Penrose drain. When stenting is used in conjunction with a meticulous surgical repair it is very unusual for any urinary drainage to occur, and in all cases the Penrose drain is removed by the third postoperative day. Although we believe there is a place for suction drains (Redivac) in urological surgery, we feel strongly that it is contraindicated adjacent to surgical repairs of the uroepithelium. Urine leakage usually indicates a mechanical problem with the stent. The management of this is simple and logical. If it appears that raised
329
THE URETERIC STENT
intravesical pressure exacerbates or contributes to leakage, a urethral catheter is inserted, often correcting the problem immediately. If this fails, then a cystogram may indicate obstruction or faulty position of the stent which can be corrected endoscopically. Undue postoperative renal pain may also indicate some mechanical problem with the stent which if corrected may prevent a urinary leak. The importance of rapid attention to the occasional mechanical problem with ureteric stents cannot be overemphasized.
SUMMARY We feel that ureteric stents do permit primary healing following procedures such as pyelotomy, ureterotomy, and nephrotomy. Stents are well tolerated by the patient, help to improve thecomfort of the convalescent period, and decrease the incidence of wound infection, stricture, and fistula. Problems with ureteric stents are rare and areeasily managed. The extra effort required to insert a ureteric stent is insignificant compared with its advantages, and we recommend its adoption. We believe that for too long surgeons have tolerated postoperative urine
330
RUSSELL ET ALll
leakage as inevitable, but it need not be. With adequate internal drainage associated with meticulous surgical repair, urine leakage and proximal urinary diversion should be phenomena of the past. REFERENCES BOYCE.W.H. (1971), Urodynamics, edited by Boyoski, S. Academic Press, Inc., New York: 513. BOYCE, W.H. (1975), Urologic Surgery, edited by Glenn, J. Harper & Row, Hageston, Maryland: 169. DAVIS.D.M. (1943), Surg. Gynec. Obstet., 76: 513. GI~BONS. R., CORREA. R., CUMMINGS. K. and MASON, J. (1976), J. Urol. (Baltimore), 115: 22. GOODWIN.W.E. (1972). Urol. Dig. 11: 13. HARRISON, L.H. and NORDAN. J. (1974). The Urologic Clinics of North America, edited by Boyce, W. W.B. Saunders & Company, volume 1 number 2: 341. HARRISON, L.H. CLARKE, S. and BOYCE. W. (1977), in Urology in Practice, edited by Devine and Stecker, Little, Brown & Company, Boston, in press. HEPPERLEN, T. and MARDIS.H. (1976), Clinical Trends in Urology, 4, 5: 1. J.T. (1975), Invest. Urol. 12: 272. LEININGER. A.T. (1968), J. Urol. MANGELSON, N., KADO.R. and COCKETT, (Baltimore), 100: 573. T. and WILKERSON, J.L. (1967). Urol. ZIMSKIND,P., FETTER. (Baltimore), 97: 840. ZIMSKIND,P. (1971), Urodynamics, edited by Boyoski, S. Academic Press, Inc., New York: 531.
AUST.N.Z. J. SURG.V0~.48-No.3, JUNE,1978
RUSSELL ET ALIl
THE USE OF THE URETERIC STENT JOHN M. RUSSELL’,STEPHEN J. CLARKE~ AND WILLIAMH. BOYCE3. Section of Urology, Bowman Gray School of Medicine of Wake Forest University, a n d North Carolina Baptist Hospital, Winston-Salem, N o r t h Carolina.
The use and placementof uretericstents either endoscopicelly or as part of an open procedure are outllned. The ureteric stent can replace the pyelostomy or nephrostomy tube and slgnlflcantly reduce the postoperatlve rnorbldity.
A PROPERLY positioned uretehc stent may act as a mould for tubular epithelial regrowth following ureteric surgery, and also provides excellent dependent drainage of the kidney allowing free passage of urine into the bladder. Others have documented the value of endoscopically placed indwelling ureteric stents in providing short or long term renal drainage; however, the place of the ureteric stent in association with open surgery on the urinary tract continues to be widely debated (Zimskind et alii 1967; Zimskind, 1971). Following renal and ureteric surgery, primary healing of the uroepithelium is a paramount aim, and factors which permit this are worthy of close scrutiny. We believe that the use of internal drainage and a meticulous surgical repair of the collecting system are the principal factors in achieving this aim. Historically surgeons have accepted leakage of urine as unavoidable following these procedures, but many believe that urinary extravasation is a contributory factor t o stricture f o r m a t i o n (Leininger, 1975). Extravasated sterile urine produces chemical intlammation and consequent cicatrization; in addition, urine is an excellent culture medium for bacterial organisms, and seepage of urine to the skin provides a portal for bacterial entry. The resultant infection will further promote scar formation and may disrupt the surgical repair, delay wound healing, and prolong I
3
M.B., B.S. (Melb.). Resident in Urology. M 8.. B S. (Melb.), Chief Resident in Urology Professor of Urology
Reprints’ William H. Boyce, M 0 , Professor of Urology, Bowman Gray
School of Medicine of Wake Forest University. Winstone-Salem. North Carolina. 27103, U.S A
AUST.N.Z. J. SURG.VOL. 48-No.3, JUNE,1978
the convalescent period (Boyce, 1971, 1975). We believe that ureteric stents help to minimize cicatrization and subsequent stricture formation by preventing urinary leakage and providing moulds for epithelial and smooth-muscle regrowth. Definition.- A major controversy in urological surgery has been “to stent or not tostent?” Even the terminology has caused some debate, perhaps due to confusion between the words splint and stent. Goodwin (1972) correctly pointed outthatasplint is something put outside a structure to keep it immobile, whereas a stent is a mould for internal fixation. We accept the definition that the term “stent” designates a device or mould, of any suitable material, used to hold a graft i n place or to provide support for tubular structures that are being anastomosed. Development.- The value of keeping urine within the urinary tract, where feasible, has long been recognized. Ureteric catheters have been used for decades, but the concept of the ureteric stent as a mould was first described by Davis (1943). The materials initially used were prone to produce tissue reaction, and consequently the use of the stents was not widely accepted. Since the development of silicone rubber (Silastic Dow-Corning Co.), which is non-reactive within the urinary tract, the vast majority of problems with ureteric stents have been overcome (Mangelson et alii, 1968). In addition, this material is flexible, will not degenerate, and can be autoclaved (Zimskind et alii, 1967; Zimskind 1971). We feel that the stent has replaced the pyelostomy and nephrostomy tube, since with good internal drainage postoperative proximal urinary diversion is now unnecessary. 327
THE URETERIC STENT
RUSSELL ET ALll
Materials- Currently a length of medical grade silicone rubber (Silastic) tubing is used to traverse the ureter between the renal pelvis and bladder. The tubing, in a variety of sizes, is available in 10-foot and 50-foot coils. It is cut to the length of a ureteric catheter and autoclaved. The most commonly used sizes are listed in Table 1. Usually several small sideholes are cut at the proximal end of the stent to facilitate pelvic drainage (Figures 1, 2).
ureteric catheter, a Silastic stent with several small side-holes cut in the proximal end, and cystoscopic foreign body forceps. The ureteric catheter, initially with guide wire in place, is well lubricated and the ureteric stent fitted over it so that ashort segment of the ureteric catheter protrudes. The stent and its guiding ureteric catheter are then passed into the renal pelvis. The position of the stent can be confirmed radiographically (by injection of some
FIGURE1: Ureteric stents: (A) Cook ureteric indwelling pigtail stent; (B) regular medical grade silicone rubber (Silastic) tubing cut to length; (C) Gibbons indwelling ureteric stent.
FIGURE2:
Loaded stent: The tipe of a regular Silastic stent loaded on to a 4 C h ureteric catheter. Note the side holes cut in the end of the stent.
Endoscopic Placement Thc situations in which endoscopic placement of a ureteric stent is indicated are summarized in Table 2. In addition to their use for decompression and drainage of the obstructed kidney, stents play a role in assessing the potential function of an obstructed kidney prior to definitive surgery. A clamped ureteric stent has also been successfully used on several occasions to tamponade unilateral renal pelvic bleeding. The required equipment for endoscopic placement is a panendoscope, a 4 CR olive-tip
328
contrast medium) or by free irrigation of the renal pelvis. The ureteric catheter is carefully removed from the stent. The stent may be pushed into the bladder with foreign body forceps or it may be brought to the outside and taped to a Foley urethral catheter. The disadvantage of leaving the stent protruding from the urethra is the risk of ascending infection, while its advantages include the accurate monitoring of urine output and stent function; the prevention of reflux; and the ease of removal. When the stent is left in the bladder, a urethral catheter is not inserted unless otherwise indicated. AUST.N.Z. J. SURG.Vo~.48-N0.3, JUNE,1978
RUSSELL ET ALll
THE URETERIC STENT
In the past many urologists have found long-term renal drainage with ureteric catheters or stents impractical because of technical difficulties including displacement and inconsistent drainage (Gibbons et alii, 1976). Recently several selfretaining stents have been developed. The Gibbons indwelling ureteric stent and the Cook* ureteric indwelling pigtail stent (Hepperlen and Mardis, 1976) both have self-retaining devices (Figure 1) and have been used with moderate success. The insertion of a Gibbons stent is a difficult exercise, and requires prior uretric dilatation. The side wings of the Gibbons stent prevent ejection from the ureter, and the lower flange prevents upward migration. A metal spring embedded in the wall of the stent renders it radio-opaque and prevents its collapse. In our experience the Cook polyethylene pigtail stent is more easily placed than the Gibbons stent, but its smaller sizeand lumen make it prone to obstruction. Both of these stents may be removed at a later date if required. As well as the recognized indications in Table 1, it is worth considering stenting the ureter when the risk of ureteric obstruction is high, as during radiotherapy for treatment of pelvic lymphoma or malignancy. TABLE1 Silastic Medical Grade Tubing
mm
Inches Intern. Dia.
Intern. Dia.
Inches Extern. Dia.
mm Extern. Dia.
0030 0062 0062 0078
076 157 157 198
0065 0095 0125 0125
165 241 318 3.18
Charriere Size
Tubing Passes through thinwalled gauge needle
73 96 96
11 8 8
Open Surgical Placement When the stent is inserted under direct visiion, it is again usual to use it over a 4 Ch ureteric catheter. It is our practice in stone surgery to insert the stent as early as feasible during the procedure. Once the stent is placed in the bladder with six to eight centimetres of surplus length to prevent retrograde migration the ureteric catheter is removed, and the correct position of the stent confirmed by free irrigation. The side holes are then cut in the proximal end of the stent, and it is positioned as desired in the pelvis or upper pole calyx (Harrison and Nordan, 1974; Harrison et alii, 1977). In critical situations the upper endof the stent may be fixed with an absorbable suture.(5/0 chromicized catgut). *
Cook Incorporated. Melbourne, Australia.
AUST. N.Z. J.
SURG.
VOL. 48-No. 3, JUNE,1978
TABLE2 Indications lor Stent Placement SHORT TERM A. Endoscopic Placement Hydronephrosis Pyonephrosis Urinary Fistula Ureteral spasm e.g. stone manipulation Preoperative positioning Postoperative repositioning B. Intraoperative Placement Pyelolithotomy Nephrolithotomy Pyeloplasty Ureterohthotomy Ureteroneocystostomy Ureteroenterostomy Ureteroureterotomy LONG TERM Endoscopic Placement Extramural malignant Ureteric obstruction Complete Incomplete Ureteric stricture Aetroperitoneal fibrosis Urinary fistula (malignant)
Stents are placed at operation during most procedures involving the ureter or pelvis (Table 2). An alternative distal placement of the ureteric stent, particularly in ureteroneocystostomy in young children and in renal transplantation, is to bring the stent to the surface with a suprapubic catheter. Stents are easily removed by grasping them through a panendoscope under local anesthesia, usually at about the seventh postoperative day. Many patients, particularly females, will pass their stents spontaneously, and they should be forewarned of this possibility. It is rare for the clinical situation to demand that a stent be replaced; however, i f necessary this can be done endoscopically. Associated Problems of Ureteral Stents Mechanical problems with stents do occur, but as the stent can be so easily removed, adjusted, or replaced endoscopically, the procedure is free of significant complications. Following most open procedures involving the uroepithelium it is usual to employ a Penrose drain. When stenting is used in conjunction with a meticulous surgical repair it is very unusual for any urinary drainage to occur, and in all cases the Penrose drain is removed by the third postoperative day. Although we believe there is a place for suction drains (Redivac) in urological surgery, we feel strongly that it is contraindicated adjacent to surgical repairs of the uroepithelium. Urine leakage usually indicates a mechanical problem with the stent. The management of this is simple and logical. If it appears that raised
329
THE URETERIC STENT
intravesical pressure exacerbates or contributes to leakage, a urethral catheter is inserted, often correcting the problem immediately. If this fails, then a cystogram may indicate obstruction or faulty position of the stent which can be corrected endoscopically. Undue postoperative renal pain may also indicate some mechanical problem with the stent which if corrected may prevent a urinary leak. The importance of rapid attention to the occasional mechanical problem with ureteric stents cannot be overemphasized.
SUMMARY We feel that ureteric stents do permit primary healing following procedures such as pyelotomy, ureterotomy, and nephrotomy. Stents are well tolerated by the patient, help to improve thecomfort of the convalescent period, and decrease the incidence of wound infection, stricture, and fistula. Problems with ureteric stents are rare and areeasily managed. The extra effort required to insert a ureteric stent is insignificant compared with its advantages, and we recommend its adoption. We believe that for too long surgeons have tolerated postoperative urine
330
RUSSELL ET ALll
leakage as inevitable, but it need not be. With adequate internal drainage associated with meticulous surgical repair, urine leakage and proximal urinary diversion should be phenomena of the past. REFERENCES BOYCE.W.H. (1971), Urodynamics, edited by Boyoski, S. Academic Press, Inc., New York: 513. BOYCE, W.H. (1975), Urologic Surgery, edited by Glenn, J. Harper & Row, Hageston, Maryland: 169. DAVIS.D.M. (1943), Surg. Gynec. Obstet., 76: 513. GI~BONS. R., CORREA. R., CUMMINGS. K. and MASON, J. (1976), J. Urol. (Baltimore), 115: 22. GOODWIN.W.E. (1972). Urol. Dig. 11: 13. HARRISON, L.H. and NORDAN. J. (1974). The Urologic Clinics of North America, edited by Boyce, W. W.B. Saunders & Company, volume 1 number 2: 341. HARRISON, L.H. CLARKE, S. and BOYCE. W. (1977), in Urology in Practice, edited by Devine and Stecker, Little, Brown & Company, Boston, in press. HEPPERLEN, T. and MARDIS.H. (1976), Clinical Trends in Urology, 4, 5: 1. J.T. (1975), Invest. Urol. 12: 272. LEININGER. A.T. (1968), J. Urol. MANGELSON, N., KADO.R. and COCKETT, (Baltimore), 100: 573. T. and WILKERSON, J.L. (1967). Urol. ZIMSKIND,P., FETTER. (Baltimore), 97: 840. ZIMSKIND,P. (1971), Urodynamics, edited by Boyoski, S. Academic Press, Inc., New York: 531.
AUST.N.Z. J. SURG.V0~.48-No.3, JUNE,1978
