0022-5347/05/1735-1595/0
THE JOURNAL OF UROLOGY®
Copyright © 2005 by AMERICAN UROLOGICAL ASSOCIATION
Vol. 173, 1595–1597, May 2005
Printed in U.S.A.
DOI: 10.1097/01.ju.0000154347.24230.f1
CAN OUTCOME OF INTERNAL URETHROTOMY FOR SHORT SEGMENT
BULBAR URETHRAL STRICTURE BE PREDICTED?
ANIL MANDHANI,* HIMANSHU CHAUDHURY, RAKESH KAPOOR, ANEESH SRIVASTAVA,
DEEPAK DUBEY AND ANANT KUMAR
From the Department of Urology and Renal Transplantation, Sanjay Gandhi Post Graduate Institute of Medical Sciences,
Lucknow, UP, India
ABSTRACT
Purpose: We predicted the outcome of visual internal urethrotomy (VIU) by measuring the
percentage of lumen narrowing at the stricture site on retrograde urethrography (RGU).
Materials and Methods: From January 1991 to June 2002 patients with primary bulbar
urethral strictures who underwent VIU were selected for the study. Patients with a history of
intervention, complete block of the urethral lumen and stricture greater than 2 cm were excluded
from study. Urethral diameter at the area of maximum stenosis and at the normal distal urethra
was measured on RGU with Vernier caliper and percentage narrowing was derived. Patients
were followed 3 times monthly with symptoms, calibration and whenever required with RGU.
Recurrence of symptoms, failure to self-calibrate and the need for secondary procedure were
considered treatment failure.
Results: Complete followup data were available in 105 patients (44 grade 1 and 61 grade 2).
Mean bulbar urethral stricture length was 0.86 cm. Inflammation was the cause of stricture in
83 (79%) and trauma the cause in 22 (21%) patients. In the Cox proportional hazards model only
grade of narrowing had a significant impact on outcome. There were 41 cases of treatment failure
in the total followup of 46 ⫾ 9 months. Mean recurrence-free duration ⫾ SD was 13 ⫾ 15 and
44.52 ⫾ 19 months in cases of treatment failure and success, respectively (p ⬍0.0001). Mean
percentage narrowing was significantly higher with treatment failure (69.9% ⫾ 16.1% vs 48.55%
⫾ 17.3%, p ⬍0.0001). A cutoff of 74% for urethral narrowing was derived to predict the outcome
with 78% probability.
Conclusions: Percentage narrowing of the urethral lumen at the stricture site is a useful
predictor of VIU outcome.
KEY WORDS: urethral stricture, treatment outcome, fibrosis
Excision with end-to-end anastomosis of short segment
(less than 3 cm) bulbar urethral stricture results in a longterm cure rate of 90% to 95%.1 In clinical practice visual
internal urethrotomy (VIU) is an easy procedure and is offered as a first modality, but the long-term results are inferior to urethroplasty with a cure rate of 33% at 10 years.2 If
factors that adversely affect the outcome of VIU are identified then they could help in prognosticating the results of
VIU.
Factors which affect the outcome of VIU are etiology, stricture length, stricture site and spongiofibrosis.1, 3 In the late
1980s ultrasonic evaluation of the urethra was proposed as a
means to assess the degree of spongiofibrosis, an important
prognosticator of outcome.4 This was based on assessing the
diameter of the urethral lumen and the thickness of the
spongiosum at the stricture. However, sonourethrography is
a subjective investigation and it requires expertise that is not
specific to define the extent and nature of spongiofibrosis. We
used retrograde urethrography (RGU) to assess the narrowing at the stricture site, which in turn depends on the degree
of spongiofibrosis, and we correlated the degree of stenosis
with the VIU outcome for short segment bulbar urethral
stricture.
PATIENTS AND METHODS
Patient records and RGU films of primary bulbar urethral
strictures treated with VIU from January 1991 to June 2002
at our institute were reviewed. Patients with a history of
intervention (dilation, internal urethrotomy or urethroplasty), stricture segment greater than 2 cm on urethrogram
and strictures with complete block were excluded from analysis. A total of 105 patients for whom complete followup and
good quality retrograde urethrography films were available
formed the study group.
Clinical decision of VIU was based on direct measurement
from the retrograde urethrography film. Percentage narrowing was measured by comparing urethral diameter at the
area of maximum stenosis with that of the normal urethra
distal to the stricture (fig. 1). Measurement for normal urethral lumen was taken distal to the stricture since this part
is distended to the maximum due to contrast instillation.
Contrast seen in the urethra proximal to the stricture and/or
in the bladder ensured proper filling of the distal urethra.
Patients with urethrogram showing intravasation as indirect
evidence of instillation of the contrast under pressure were
excluded from study.
All patients underwent urethroscopy followed by VIU as an
inpatient procedure using a 21Fr Sachse’s urethrotome. Patients were kept on daily self-calibration with 18Fr Foley
catheter on a protocol basis for a minimum of 2 years. Recurrence of symptoms, failure to self-calibrate and the need
for secondary procedures (dilation, internal urethrotomy or
urethroplasty) were considered treatment failures.
Submitted for publication August 12, 2004.
* Correspondence: Department of Urology and Renal Transplantation, Sanjay Gandhi Post Graduate Institute of Medical Sciences,
Lucknow, UP, India (telephone: 91–522-668678; FAX: 91–522668017; e-mail: [email protected]).
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INTERNAL URETHROTOMY FOR SHORT SEGMENT BULBAR URETHRAL STRICTURE
FIG. 1. Diagrammatic representation of calculating percentage
narrowing of urethral stricture.
Logistic regression analysis was done to assess the effects
of percentage narrowing, length of stricture and etiology on
the outcome of VIU. Kaplan-Meier analysis was used to assess recurrence-free duration. Binary logistic regression was
used to derive a model to predict treatment failure using
percentage narrowing.
RESULTS
Mean patient age was 41.98 ⫾ 16.41 years (range 8 to 73).
Mean symptom duration was 9.72 ⫾ 6.1 months (range 2 to
35). Strictures were inflammatory in 83 (79%) and traumatic
in 22 (21%) patients. Mean stricture length on radiographic
film was 0.868 cm. All these strictures were documented on
urethroscopy and there were no false-positive cases in this
group. None of the cases had stricture length greater than 2
cm on urethroscopy. Mean followup was 46.09 ⫾ 22.2 months
(range 9 to 106).
On logistic regression analysis the percentage of stricture
segment on radiographic film was found to affect the outcome
significantly with an odds ratio of 0.15. There were significant differences in percentage narrowing, 48.2% ⫾ 17% vs
69.9% ⫾ 16%, p ⬍0.0001, and recurrence-free duration
44.52 ⫾ 19 vs 13 ⫾ 15 months, between VIU successes and
failures.
Of 41 cases of treatment failure 28 (70.7%) underwent
second VIU, 8 (19.5%) underwent urethroplasty and 1 is on
frequent dilation. Of 28 patients who had second VIU, treatment failed again in 15 (53.5%) at a median interval of
11 months. Of these 15 patients urethroplasty has been done
in 12.
The model to predict the chance of treatment failure was
derived using binary logistic regression analysis and written
as x ⫽ - 4.6167 ⫹ (0.0698 ⫻ n), where n is the percentage of
lumen narrowing on radiographic urethrography. If x is 0.5
or less VIU will most likely have a favorable outcome and if
x is greater than 0.5 the patient will most likely have stricture recurrence. This model had a predictability of 81.3% and
70.7% for treatment success and failure, respectively. Overall
predictability of the model was 77.9%. Based on this model
a cutoff for urethral narrowing of 74% was derived (figs. 2
and 3).
would be of great value in assigning prognosis to these patients and in guiding reconstructive surgery.
Although stricture length is often underestimated with
RGU, in clinical practice it is the most commonly used imaging to decide VIU as a treatment modality for short segment
bulbar urethral structure.7⫺10 Only retrograde urethrogram
was used to assess stricture length in the present study since
good proximal urethral filling was seen in all cases.
The urethral wall is normally thin, smooth, elastic and
easily distensible on retrograde injection of contrast. However, fibrosis of the urethral wall makes it thick, irregular
and nondistensible. This fibrosis of spongiosum can be measured by the degree of encroachment upon the urethral lumen.
Thus, the spongiofibrosis or stricture density in various
grades is said to be a critical determinant of appropriate
therapy and ultimate prognosis.7 Sonourethrography has
been used to measure the spongiofibrosis and its grades by
comparing the luminal diameter at the stricture site with the
normal urethral diameter during maximal retrograde distention.4, 11 Studies regarding the grading of spongiofibrosis are
limited in the current literature and those assessing its effect
on the outcome of surgery for stricture disease are even more
sparse. Although the sonourethrogram was meant to grade
the degree of fibrosis, the subjectivity and low specificity to
identify spongiofibrosis have hindered its widespread use.
The present technique of measuring circumferential narrowing is an offshoot of the principle of grading spongiofibrosis on sonourethrogram where encroachment of the lumen is
taken into the consideration. Measuring the luminal diameter at the area of maximum stenosis with retrograde urethrography film could indirectly be representative of the
degree of fibrosis. This measurement is not affected by patient positioning since the axis of the x-ray is perpendicular
to the length measured. If the findings are interpreted as
percentage narrowing of the normal urethral lumen, variability in the magnification is also taken into account.
FIG. 2. RGU showing bulbar urethral stricture with 45% lumen
narrowing and 48 months recurrence-free.
DISCUSSION
Although the safety and ease of the procedure makes VIU
the treatment of first choice for short segment bulbar urethral strictures, the success rate of urethrotomy at 5 years is
less than that of urethroplasty (50% compared with 83%) and
at 10 years it is just 33%.2, 5, 6 There are no explicit guidelines
for the need and frequency of VIU and, similarly, there is not
enough evidence in the current literature to say that repeat
VIU does not increase stricture length and severity. Therefore, judicious use of a presumably innocuous procedure
should be reconsidered based on some parameters that could
predict outcome. Thus, identification of factors that portend
poor outcome in patients undergoing internal urethrotomy
F IG . 3. RGU showing bulbar urethral stricture with 84%
lumen narrowing and 8 months recurrence-free.
INTERNAL URETHROTOMY FOR SHORT SEGMENT BULBAR URETHRAL STRICTURE
In our study percentage of narrowing as assessed on RGU
film was found to affect the outcome significantly
nsrsid610893⫼elrsid610893 after VIU. This technique of indirect measurement of spongiofibrosis is objective and proportional narrowing can be calculated on a good RGU film.
Factors that could affect the measurement are underfilling
and overfilling of the distal urethra. If there is adequate
contrast filling of the bladder and/or proximal urethra then
there is proper filling of the distal urethra. RGU film with
intravasation of contrast denotes overfilling and was excluded from study. If confounding factors like stricture
length, site and etiology are eliminated then the degree of
narrowing could have an important role in the outcome of
VIU. Thus, circumferential narrowing would help in prognosticating the outcome.
Although one could argue in favor of repeat VIU to avoid a
major reconstructive procedure, 1 study has demonstrated
that there is no increase in success with a second internal
urethrotomy.2 In the present study there was also a 53.5%
failure to second VIU at a median followup of 11 months.
Although there is not enough evidence that multiple internal
urethrotomies and dilations will adversely affect the outcome
of urethroplasty, theoretically it seems logical that the repeated trauma of urethrotomy would increase fibrosis and
perhaps increase stricture length. In the present study 10
patients who required urethroplasty had preputial onlay,
which otherwise could have been managed initially with
end-to-end urethroplasty.
Based on our cohort of patients we reached a cutoff of 74%
urethral narrowing. A prediction of adverse outcome of VIU
in patients with urethral narrowing greater than 74% can be
made with a predictability of 78%. Preoperative determination of the percentage of narrowing on RGU can thus be used
to assign prognosis in patients with short segment bulbar
urethral strictures. One of the limitations of the present
study is that results following VIU are not a true reflection of
the procedure since the patients were kept on self-calibration
with an 18Fr Foley catheter at the outset as per the protocol.
CONCLUSIONS
Determining the percentage narrowing of the stricture segment on retrograde urethrography film is an easy and feasible method of predicting the outcome of VIU in short segment
bulbar urethral stricture. Percentage narrowing of more than
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74% could correctly predict treatment failure in 78% of patients. Alternative treatment should be considered first for
short segment bulbar stricture with high grade narrowing,
with a significantly shorter recurrence-free interval and high
chances of treatment failure.
Dr. Uttam Singh, Associate Professor, Department of Biostatistics, assisted with statistical analysis.
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