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Coaxial balloon dilation and calibration of urethral strictures
Dilation andCalibrationof Urethral Sdctwes
Jerry D. Qtesy, MD, FACS, Portland, Oregon James C. Finn, BA, Palo Alto, California -a~ 0. Hermann, MIME, Palo Alto, California , Palo Alto, California -8.--Y, Thomas J. Fo@arty, MD, FACS, Palo Alto, California
Current techniques of urethral dilation involving the sequential passage of fixed diameter dilators entail technical deficiencies that may increase the rate of procedural and long-term complications [l-3]. Use of vascular b&on dilatation catheter73in the urethra to overcome theee deficiencies has been reported with good initial results [3,4]. The balloons utilized to date, however, have not been designed for the urologic system. Herein, we report an initial clinical and laboratory evaluation of new urethral baboon dilators designed with standard urologic tip configurations. Balloon catheters clearly permit variability of rigidity and diameter, ease of introduction, and allow less instrumentation of the urethra. Material
and Methods
Three adult coaxial balloon urethral dilators were developed as a result of comparative studies of currently used dilators. The balloons utilixed were nonelastomeric, having a relatively fixed maximum diameter and volume of inflation. The male coaxial instrument has a collapsed outer diameter of 9 F., an inflated outer diameter of 24 F., and either a coud&or Phillips screw tip catheter (Figure 1). The female version was designed over a straight, blunt-nosed catheter body, and its outer diameter enlarges from 9 to 30 F. when inflated. All balloons can be maximally inflated to approximately 120 pounds per square inch. Coaxial urethral balloons were evaluated 51 times in 41 patients for clinical application ranging from urethral calibration to dilation of severe urethral strictures (Figure 2). The cause of stricture varied and included congenital, infection, instrumentation, trauma, and operative manipulation. Two patients with urethrovesicle strictures after radical prostatectomy and two with internal urethrotomy were included. Both of the internal urethrotomy patients were placed on a program of clean, nonsterile in-
tern&tent self-dilation patterned after the concept of intermittent self-catheterization by Lapides [5,6]. Assessment of urethral caliber before and after dilation was obtained with selected use of bougies, urethrograms, and clinical status in this heterogeneous population. The Fogarty embolectomy (latex balloon) catheter was used 88a simple, adjustable bougie for many calibration applications. R9SUttS
The immediate procedural results of the evaluation are summarized in Table I. The severity of the stricture was subjectively classified as minimal, moderate, or severe resistance to radial dilation as gauged by the force required on the syringe to dilate. Patients were classified into either one of the stricture categories or were considered within the calibration category as part of a preoperative evaluation or consultation. All catheters were & and located across the stricture easily, with o&y two of the male patients (both with severe strictures) requiring filiform attachments for placement. All clinical goals were achieved, and no complications were identified. Because of the physical heterogeneity of urethral strictures and the diverse nature of their histories, it is difficult to cross-compare long-term results between groups of strictures treated with different techniques. A general clinical impression can be drawn, however. Minimal disease is usually very responsive to dilation, whereas certain severe strictures clearly resist long-term benefit from any single or staged procedure. There clearly appears to be sufficient radial pressure countered.
to dilate
moat strictures
en-
Comments Desirable characteristics of a urethral dilator include adjustability of size and rigidity (reflected by the pressure in a balloon); low, emooth silhouette upon introduction and withdraw& variability of use
vahma 147, my
lea4
611
Giesy el al
Q
QF-3OF
L
QF--24F
FLEXl8i.E CC4JOE TIP
- ..___ .
COUPATIBLE WIT” f1LlfORUS. TIC.
Ftgwe 1. Fundamentaldilator designs used in clinical study. Catheter bodies were f/t&d with bhmt, coo&,
as a calibrator or dilator; and ability to use a minimum number of configurations in a maximum number of situations. These criteria would decrease instrumentation of the urethra, decrease trauma to the mucosa, increase the sensitivity to resistance of placement and dilation, decrease the total number of instrument configurations required, and reduce the discomfort of the procedure. Fortunately, the majority of male urethral strictures permit the relatively easy passage of either a 9 F. coud6 catheter or a 5 F. filiform-tipped catheter without significant shear force (the frictional force between catheter and mucosa). Coaxial balloons can be made in these sizes with good handling characteristics. The external smoothness and low silhouette of the collapsed balloon has been possible by careful design of the balloon tip and the longitudinal pleats placed in the collapsed balloon. After inflation, the inherent “memory” in the pleats returns the balloon to nearly its original shape when aspirated and thus allows reintroduction with minimal resistance.
or screw tips to enhance
Maximum inflated balloon diameters of 24 and 30 F. in two instruments provide the most commonly used sizes for male and female applications. By varying infusion pressure or using a 24 F. dilator for female patients and a 30 F. dilator for male patients, the clinical variability utilizing these two devices may be further enhanced. Coaxial dilators can be varied to work as dilators or as calibrators. By inflation before insertion, the device provides a “feel” for the urethra, similar to a conventional Van Buren sound dilator. By placing it in the bladder and then inflating it (in female patients), it operates as an inflatable bougie during withdrawal. By inflation in the urethra, it communicates the degree of resistance to inflation and, thus, stricture rigidity to the physician and subsequently dilates when pressure is increased. By adjusting its position, linearly selective dilation occurs. The female dilator is lightweight and the relatively stiff shaft provides an opportunity to observe urethral and bladder neck angle in the lithotomy and standing
F&ire 2. The ollatlng p&c&h. The balWlisphatedoMothecaMetefbodyand heatsettoredncenepn?WuponI~ &Non.
612
llto Amerhn
JoumJol SuoWr
M
Minimal
F
Resistance Moderate F M
M
severe
F
Calbration+ F M
Clinkal Aopkations sMcture dWon lnWtton, trauma,transmthral resectkmprostate, internal ve8rrotomy, Dim
mka~
Gabration
Part of aen~huuY
14
19
...
3
. . .
. . .
. . .
...
...
...
...
...
.,.
4
6
*. . ...
4
..*
6 ...
. *. ...
4
6
...
...
...
4
6
1::
1::
1::
...
... ...
... ...
PmstectomY
evabatbn
caseofaocess Favorable DifficlJR
Effective Yes No
hlstrused coaxhl only
Coaxiala other dilators Needforlargerdiametterbalbon
Homes8lf~ lwxmntme urm
5
5
14
19
...
3
...
...
...
...
...
5
14
19
...
...
. *.
...
..
...
5
14
14
...
1::
1::
‘s
1::
1 2 ...
...
1 ...
...
... tollon-up
1
...
...
3
...
...
...
l Nmbers Wcete dHations or calibratkmswithin eachcategory. + No resistance.
positions and changes that occur during coughing and straining. Balloon memory provides the option of studying several of the above with a single instrument or reusing the catheter for self-intermittent dilation, constantly regaining a low silhouette upon aspiration. Dilating pressure may be varied up to approximately 120 pounds per square inch without balloon rupture. Maximum hand pressure, utilizing a 10 ml syringe, normally varies between 85 and 100 pounds per square inch, thus providing a margin of safety. A pressure gauge is definitely advisable, at least until the clinician becomes accustomed to the instrument. The proper dilating force appears to have a wide range and varies greatly with clinical conditions. Postoperative internal urethrotomy patients can appear to be completely dilated at approximately 40 pounds per square inch, and severe strictures appear to require levels between 50 and 75 pounds per square inch to adequately stretch the densely fibrous tissue. Obviously, a definite degree of clinical sensitivity and experience is required to safely vary these pressures in keeping with tissue tolerances and clinical goals. Overall, the coaxial balloon dilator provides the following advantages over conventional techniques: (1) low silhouette with improved access and decreased tissue resistance to advancement (Figure 3, top); (2) variability of pressure, caliber, and time of dilation, (3) decreased instrumentation, and (4) im-
VeLrm 147,way1084
proved opportunity for self-dilation through simplification of the technique of dilation and ability to dilate to optimal discomfort tolerance. Coaxial dilators require a period of familiarization to develop a feeling for the different dilating pressures necessary in the various clinical settings. The most appropriate combinations of rate, caliber, and frequency of dilatation are currently being worked out. It is our clinical impression that slow, gradual, repeated dilations are clearly superior to more rapid, abrupt, aggressive dilatations. There is histologic evidence in human subjects that smooth muscle and elastic tissue comprise a significant component of the scar tissue of many urethral strictures [7]. This finding is consistent with the concept that slow, gradual dilation, allowing relaxation of these components, may be important in minimizing urethral trauma and the rate of new scar formation. This slow dilatation can only be practically achieved with balloon dilators (Figure 3, bottom). The program of intermittent self-dilation has proved very successful in maintaining internally urethrotomized strictures. Patients readily learn how to catheterize and dilate themselves, and the ability to dilate to their own discomfort tolerance consequently encourages compliance with the program. We are currently expanding the number of patients in this program and will make their results the subject of a later report.
613
Glesy et
al
strictures including improved access and decreased mucosal trauma due to a low silhouette, adjustability of diameter and rigidity, decreased instrumentation, and facilitation of intermittent self-dilation by the patient. The instruments were evaluated in 51 strictures (41 patients) as both a dilator and a calibrator. All catheters were located across the stricture easily (although two required filiform attachments). All clinical goals were achieved, and no complications were identified. Two patients were started on a program of intermittent self-dilation after internal urethrotomy with good results. It is our initial clinical impression that slow, gradual dilation of strictures is superior to rapid, abrupt dilation. This can only be practically achieved with balloon dilators. References 1. Devereux MH, Burfield Go. Prolonged follow-up of urethral 2. 3. FJg~re 3. Sommaty of certain advantages of the balkon dilator. Note that stress designates the force magnttmk per untt of area over whkh tt acts, and can be thooght of as force densfty.
4. 5.
Summary New coaxial balloon dilators with standard urologic tip configurations have been designed for use in urethral strictures. Balloon dilatation provides several advantages over conventional dilatation of
614
6.
7.
strictures treated by intermittent dilatation. Br J Urol 1970; 42:321-g. Chambers FM, Baitera B. The anatomy of the urethral stricture. Br J Urol 1977;49:545-51. Russlnovlch NAE, Lloyd LK. &lggs WP, Jander HP. Balloon dilatation of urethral strictures. Urol Radio11980;2:33-7. Pinot JJ, Herrnanowicz M, Bonnet JL, Kasbarlan M, Ducassou J. Dilatation uretrale par sonde a ballonnet gonflable. Press Med 1983;12:163-4. Lapides J, Diokno AC, Silber SJ, Lowe BS. Clean, intermittent self-catheterization in the treatment of urinary tract disease. J Urol 1972;107:458-81. Lapides J. Diokno AC, Lowe BS, Kalish MD. Followup on unsterile, intermittent self-catheterization. J Urol 1974; 111: 184-7. Singh M, Blandy JP. The pathology of urethral stricture. J Urol 1976;115:673-6.
The AmericanJournalof Surgery
Jerry D. Qtesy, MD, FACS, Portland, Oregon James C. Finn, BA, Palo Alto, California -a~ 0. Hermann, MIME, Palo Alto, California , Palo Alto, California -8.--Y, Thomas J. Fo@arty, MD, FACS, Palo Alto, California
Current techniques of urethral dilation involving the sequential passage of fixed diameter dilators entail technical deficiencies that may increase the rate of procedural and long-term complications [l-3]. Use of vascular b&on dilatation catheter73in the urethra to overcome theee deficiencies has been reported with good initial results [3,4]. The balloons utilized to date, however, have not been designed for the urologic system. Herein, we report an initial clinical and laboratory evaluation of new urethral baboon dilators designed with standard urologic tip configurations. Balloon catheters clearly permit variability of rigidity and diameter, ease of introduction, and allow less instrumentation of the urethra. Material
and Methods
Three adult coaxial balloon urethral dilators were developed as a result of comparative studies of currently used dilators. The balloons utilixed were nonelastomeric, having a relatively fixed maximum diameter and volume of inflation. The male coaxial instrument has a collapsed outer diameter of 9 F., an inflated outer diameter of 24 F., and either a coud&or Phillips screw tip catheter (Figure 1). The female version was designed over a straight, blunt-nosed catheter body, and its outer diameter enlarges from 9 to 30 F. when inflated. All balloons can be maximally inflated to approximately 120 pounds per square inch. Coaxial urethral balloons were evaluated 51 times in 41 patients for clinical application ranging from urethral calibration to dilation of severe urethral strictures (Figure 2). The cause of stricture varied and included congenital, infection, instrumentation, trauma, and operative manipulation. Two patients with urethrovesicle strictures after radical prostatectomy and two with internal urethrotomy were included. Both of the internal urethrotomy patients were placed on a program of clean, nonsterile in-
tern&tent self-dilation patterned after the concept of intermittent self-catheterization by Lapides [5,6]. Assessment of urethral caliber before and after dilation was obtained with selected use of bougies, urethrograms, and clinical status in this heterogeneous population. The Fogarty embolectomy (latex balloon) catheter was used 88a simple, adjustable bougie for many calibration applications. R9SUttS
The immediate procedural results of the evaluation are summarized in Table I. The severity of the stricture was subjectively classified as minimal, moderate, or severe resistance to radial dilation as gauged by the force required on the syringe to dilate. Patients were classified into either one of the stricture categories or were considered within the calibration category as part of a preoperative evaluation or consultation. All catheters were & and located across the stricture easily, with o&y two of the male patients (both with severe strictures) requiring filiform attachments for placement. All clinical goals were achieved, and no complications were identified. Because of the physical heterogeneity of urethral strictures and the diverse nature of their histories, it is difficult to cross-compare long-term results between groups of strictures treated with different techniques. A general clinical impression can be drawn, however. Minimal disease is usually very responsive to dilation, whereas certain severe strictures clearly resist long-term benefit from any single or staged procedure. There clearly appears to be sufficient radial pressure countered.
to dilate
moat strictures
en-
Comments Desirable characteristics of a urethral dilator include adjustability of size and rigidity (reflected by the pressure in a balloon); low, emooth silhouette upon introduction and withdraw& variability of use
vahma 147, my
lea4
611
Giesy el al
Q
QF-3OF
L
QF--24F
FLEXl8i.E CC4JOE TIP
- ..___ .
COUPATIBLE WIT” f1LlfORUS. TIC.
Ftgwe 1. Fundamentaldilator designs used in clinical study. Catheter bodies were f/t&d with bhmt, coo&,
as a calibrator or dilator; and ability to use a minimum number of configurations in a maximum number of situations. These criteria would decrease instrumentation of the urethra, decrease trauma to the mucosa, increase the sensitivity to resistance of placement and dilation, decrease the total number of instrument configurations required, and reduce the discomfort of the procedure. Fortunately, the majority of male urethral strictures permit the relatively easy passage of either a 9 F. coud6 catheter or a 5 F. filiform-tipped catheter without significant shear force (the frictional force between catheter and mucosa). Coaxial balloons can be made in these sizes with good handling characteristics. The external smoothness and low silhouette of the collapsed balloon has been possible by careful design of the balloon tip and the longitudinal pleats placed in the collapsed balloon. After inflation, the inherent “memory” in the pleats returns the balloon to nearly its original shape when aspirated and thus allows reintroduction with minimal resistance.
or screw tips to enhance
Maximum inflated balloon diameters of 24 and 30 F. in two instruments provide the most commonly used sizes for male and female applications. By varying infusion pressure or using a 24 F. dilator for female patients and a 30 F. dilator for male patients, the clinical variability utilizing these two devices may be further enhanced. Coaxial dilators can be varied to work as dilators or as calibrators. By inflation before insertion, the device provides a “feel” for the urethra, similar to a conventional Van Buren sound dilator. By placing it in the bladder and then inflating it (in female patients), it operates as an inflatable bougie during withdrawal. By inflation in the urethra, it communicates the degree of resistance to inflation and, thus, stricture rigidity to the physician and subsequently dilates when pressure is increased. By adjusting its position, linearly selective dilation occurs. The female dilator is lightweight and the relatively stiff shaft provides an opportunity to observe urethral and bladder neck angle in the lithotomy and standing
F&ire 2. The ollatlng p&c&h. The balWlisphatedoMothecaMetefbodyand heatsettoredncenepn?WuponI~ &Non.
612
llto Amerhn
JoumJol SuoWr
M
Minimal
F
Resistance Moderate F M
M
severe
F
Calbration+ F M
Clinkal Aopkations sMcture dWon lnWtton, trauma,transmthral resectkmprostate, internal ve8rrotomy, Dim
mka~
Gabration
Part of aen~huuY
14
19
...
3
. . .
. . .
. . .
...
...
...
...
...
.,.
4
6
*. . ...
4
..*
6 ...
. *. ...
4
6
...
...
...
4
6
1::
1::
1::
...
... ...
... ...
PmstectomY
evabatbn
caseofaocess Favorable DifficlJR
Effective Yes No
hlstrused coaxhl only
Coaxiala other dilators Needforlargerdiametterbalbon
Homes8lf~ lwxmntme urm
5
5
14
19
...
3
...
...
...
...
...
5
14
19
...
...
. *.
...
..
...
5
14
14
...
1::
1::
‘s
1::
1 2 ...
...
1 ...
...
... tollon-up
1
...
...
3
...
...
...
l Nmbers Wcete dHations or calibratkmswithin eachcategory. + No resistance.
positions and changes that occur during coughing and straining. Balloon memory provides the option of studying several of the above with a single instrument or reusing the catheter for self-intermittent dilation, constantly regaining a low silhouette upon aspiration. Dilating pressure may be varied up to approximately 120 pounds per square inch without balloon rupture. Maximum hand pressure, utilizing a 10 ml syringe, normally varies between 85 and 100 pounds per square inch, thus providing a margin of safety. A pressure gauge is definitely advisable, at least until the clinician becomes accustomed to the instrument. The proper dilating force appears to have a wide range and varies greatly with clinical conditions. Postoperative internal urethrotomy patients can appear to be completely dilated at approximately 40 pounds per square inch, and severe strictures appear to require levels between 50 and 75 pounds per square inch to adequately stretch the densely fibrous tissue. Obviously, a definite degree of clinical sensitivity and experience is required to safely vary these pressures in keeping with tissue tolerances and clinical goals. Overall, the coaxial balloon dilator provides the following advantages over conventional techniques: (1) low silhouette with improved access and decreased tissue resistance to advancement (Figure 3, top); (2) variability of pressure, caliber, and time of dilation, (3) decreased instrumentation, and (4) im-
VeLrm 147,way1084
proved opportunity for self-dilation through simplification of the technique of dilation and ability to dilate to optimal discomfort tolerance. Coaxial dilators require a period of familiarization to develop a feeling for the different dilating pressures necessary in the various clinical settings. The most appropriate combinations of rate, caliber, and frequency of dilatation are currently being worked out. It is our clinical impression that slow, gradual, repeated dilations are clearly superior to more rapid, abrupt, aggressive dilatations. There is histologic evidence in human subjects that smooth muscle and elastic tissue comprise a significant component of the scar tissue of many urethral strictures [7]. This finding is consistent with the concept that slow, gradual dilation, allowing relaxation of these components, may be important in minimizing urethral trauma and the rate of new scar formation. This slow dilatation can only be practically achieved with balloon dilators (Figure 3, bottom). The program of intermittent self-dilation has proved very successful in maintaining internally urethrotomized strictures. Patients readily learn how to catheterize and dilate themselves, and the ability to dilate to their own discomfort tolerance consequently encourages compliance with the program. We are currently expanding the number of patients in this program and will make their results the subject of a later report.
613
Glesy et
al
strictures including improved access and decreased mucosal trauma due to a low silhouette, adjustability of diameter and rigidity, decreased instrumentation, and facilitation of intermittent self-dilation by the patient. The instruments were evaluated in 51 strictures (41 patients) as both a dilator and a calibrator. All catheters were located across the stricture easily (although two required filiform attachments). All clinical goals were achieved, and no complications were identified. Two patients were started on a program of intermittent self-dilation after internal urethrotomy with good results. It is our initial clinical impression that slow, gradual dilation of strictures is superior to rapid, abrupt dilation. This can only be practically achieved with balloon dilators. References 1. Devereux MH, Burfield Go. Prolonged follow-up of urethral 2. 3. FJg~re 3. Sommaty of certain advantages of the balkon dilator. Note that stress designates the force magnttmk per untt of area over whkh tt acts, and can be thooght of as force densfty.
4. 5.
Summary New coaxial balloon dilators with standard urologic tip configurations have been designed for use in urethral strictures. Balloon dilatation provides several advantages over conventional dilatation of
614
6.
7.
strictures treated by intermittent dilatation. Br J Urol 1970; 42:321-g. Chambers FM, Baitera B. The anatomy of the urethral stricture. Br J Urol 1977;49:545-51. Russlnovlch NAE, Lloyd LK. &lggs WP, Jander HP. Balloon dilatation of urethral strictures. Urol Radio11980;2:33-7. Pinot JJ, Herrnanowicz M, Bonnet JL, Kasbarlan M, Ducassou J. Dilatation uretrale par sonde a ballonnet gonflable. Press Med 1983;12:163-4. Lapides J, Diokno AC, Silber SJ, Lowe BS. Clean, intermittent self-catheterization in the treatment of urinary tract disease. J Urol 1972;107:458-81. Lapides J. Diokno AC, Lowe BS, Kalish MD. Followup on unsterile, intermittent self-catheterization. J Urol 1974; 111: 184-7. Singh M, Blandy JP. The pathology of urethral stricture. J Urol 1976;115:673-6.
The AmericanJournalof Surgery