|Year : 2018 | Volume
| Issue : 4 | Page : 107-110
Validation of the role of retrograde urethrogram in the management of urethral strictures
Nasir Oyelowo, Muhammed Ahmed, Ahmad Bello, Lawal A Tijani, Maitama H. Y. L Bola Bilyaminu, Musliu A Tolani, Adetola M Tolani, Sudi Abdullahi, Awaisu Mudi, Jemila Olagunju
Ahmadu Bello University Teaching Hospital Zaria, Kaduna, Nigeria
|Date of Web Publication||20-Sep-2019|
Dr. Nasir Oyelowo
Department of Surgery, Ahmadu Bello Teaching Hospital Zaria, PMB 06, Zaria
Introduction: Urethral stricture is a common cause of lower urinary tract symptoms in the middle aged and elderly men in our environment. Its diagnosis and management is hinged mainly on a retrograde urethrogram (RUG) that is associated with variable lengths and sites with that found intraoperatively due to difference in magnification (source patient as well as source image distance), penile stretch, and positioning during the procedure. We hereby sort to validate this tool in defining urethral strictures. Materials and Methods: Adult patients with lower urinary tract symptoms suspected to be due to urethral strictures who presented to the outpatient department and emergency departments of the hospital between January 2016 to December 2016 were recruited into the study. This was followed by obtaining an informed consent from the patient and ethical clearance from the institution. Patients who were not fit or not willing to have a urethroplasty were excluded from the study. The recruited patients had RUG to characterize the strictures. The intraoperative findings at urethroplasty were compared with that found on RUG. Data were collected and analyzed using SPSS version 23 to determine sensitivity specificity of the test. Results: A total of 84 patients were studied during the period. The mean age of the patients was 44.1 years. Bulbar strictures accounted for 65% of the strictures. Most of the strictures were single (72%) and long segment (52%). Sensitivity and specificity of RUG in determination of the length of stricture were 76.9% and 74.6%, respectively, whereas the sensitivity and specificity of RUG in determination of site of stricture were 92.9% and 96.4%, respectively. The determination of number of stricture on RUG has a sensitivity of 94.2% and specificity of 90.8%. Conclusion: RUG is a valuable tool in the management of urethral strictures with a higher sensitivity and specificity for the determination of site and number of strictures as compared to length of stricture that is more affected by magnification and techniques in contrast administration. This should be considered during procedure as well as during interpretation of images.
Keywords: Diagnosis urethral strictures, retrograde urethrogram
|How to cite this article:|
Oyelowo N, Ahmed M, Bello A, Tijani LA, Bola Bilyaminu MH, Tolani MA, Tolani AM, Abdullahi S, Mudi A, Olagunju J. Validation of the role of retrograde urethrogram in the management of urethral strictures. Sub-Saharan Afr J Med 2018;5:107-10
|How to cite this URL:|
Oyelowo N, Ahmed M, Bello A, Tijani LA, Bola Bilyaminu MH, Tolani MA, Tolani AM, Abdullahi S, Mudi A, Olagunju J. Validation of the role of retrograde urethrogram in the management of urethral strictures. Sub-Saharan Afr J Med [serial online] 2018 [cited 2020 May 28];5:107-10. Available from: http://www.ssajm.org/text.asp?2018/5/4/107/267129
| Introduction|| |
The diagnosis of urethral stricture is key to its management. It involves not only the determination of mere presence of the stricture but also the characteristics of the stricture. There are various tools used in diagnosis of urethral strictures with inherent pros and cons of each tool. The retrograde urethrogram (RUG) occupies a central role in the diagnosis of urethral strictures and is recognized as the most widely used tool compared to sonourethrography, magnetic resonance urethrography, or urethrocystoscopy. It is reproducible and gives objective detail of the site, number, length of stricture, and whether it is a complete stricture or not. It is, however, devoid of information on the extent of spongiofibrosis and extent of healthy mucosa around the stricture that may be found on sonourethrography and at urethrocystoscopy, respectively.,, It is also influenced by penile stretching and position of the patient during the procedure. A micturating cystourethrogram is a dynamic and more physiological imaging as compared with the RUG; however, in our environment due to late presentation of most our patients with strictures, RUG remains the investigation of choice and often combined with a micturating cystourethrogram in patients with complete strictures.
The radiation exposure and two-dimensional static images of the RUG have raised questions on its role in the diagnosis of urethral stricture. We hereby sort to validate the role of this diagnostic tool in the management of urethral stricture in our hospital.
| Materials and methods|| |
Adult patients with lower urinary tract symptoms suspected to be due to urethral strictures who presented to the outpatient department and emergency departments of the hospital between January 2016 to December 2016 were recruited into the study. This was followed by obtaining an informed consent from the patient and ethical clearance from the institution. Patients excluded from the study included patients with contrast allergies, those not fit for urethroplasty, and those managed by dilatations or urethrotomies. The recruited patients had RUG to characterize the strictures.
RUG was performed while the patients had an empty bladder, and in right oblique position with the right leg flexed and the left leg stretched over. A precontrast (control) image was obtained and subsequently a 12F urethral catheter was inserted into the fossa navicularis of the urethra. The catheter was used to instill 20 mL of urografin and two oblique radiographs of the pelvis was obtained. The radiographs were interpreted to determine site, number, and length of strictures. A micturating cystourethrogram was used to compliment the RUG in complete strictures A retrograde urethrogram of a catheter induced stricture is shown in [Figure 1] below.
At urethroplasty, the strictures were redefined following exposure of the urethra to determine the site and number of strictures. The length was measured intraoperatively using a rule as shown in [Figure 2] below. Data were collected on a study proforma and analyzed using SPSS version 23 to determine sensitivity and specificity of the test. The results were displayed in tables and figures.
| Results|| |
A total of 84 patients were studied during the period. The mean age of the patients was 44.1 years. Bulbar strictures accounted for 65% of the strictures. Most of the strictures were long segment (52%). The site, number, and length of the strictures obtained on the RUG and at urethroplasty are displayed in the [Table 1].
|Table 1 Characteristics of the strictures found on RUG and at urethroplasty|
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The sensitivity and specificity of RUG in the determination of the length of urethral stricture was calculated following a cross-tabulation with findings at urethroplasty on SPSS that is displayed in [Table 2].
|Table 2 Length of stricture on retrograde urethrogram and at urethroplasty|
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Similar cross-tabulation and calculation was made to determine the sensitivity and specificity of RUG in the determination of site and number of strictures. The results are displayed in [Table 2].
| Discussion|| |
Urethral strictures are narrow and loss of distensbility of the anterior urethra due to trauma or inflammation result in spongiofibrosis. Its diagnosis and management is typically based on imaging of the urethra., The RUG first described in 1910 by Cunnnigham remains the standard imaging in diagnosis and postoperative evaluation of patients with urethral strictures.
Other modalities include sonourethrography, magnetic resonance urethrography, and urethrocystoscopy. Sonourethrograhy has been found to be a good adjunct to the RUG in the management of strictures as it provides a better stricture length and extent of spongiofibrosis. It is also readily available and not associated with radiation exposure. It however depends on the expertise of an experienced sonographer and distension of the urethral lumen. Sonourethrography is also limited in proximal bulbar strictures where a transperineal scan is required. Magnetic resonance imaging like sonourethrography has good soft tissue details on periurethral fibrosis and an excellent assessment stricture length. It is however not readily available. Urethroscopy gives the best assessment of the urethral mucosa and may be done concurrently during visual urethrotomies; it is, however, limited in assessment of stricture length especially in complete strictures.
The RUG provides good assessment of the number, site, and length of strictures. It does this by opacification and distension of the urethral lumen.,, As such, the interpretation of the RUG depends on proper positioning, penile stretch, and instillation of contrast. Inadequate distension and opacification may lead to poor assessment of stricture length. This length of stricture may also be overestimated due to magnification. The luminal opacification gives no details of the spongiofibrosis. Despite these limitation, it is still considered the gold standard imaging of choice in management of urethral strictures.
In this study, the ability of RUG to determine the precise site and number of stricture is excellent by its high sensitivity and specificity of 92.90% and 94.60%, and 94.20% and 90.80%, respectively, as compared with the findings at urethroplasty. As inferred, the specificity (76.40%) and sensitivity (76.90%) were relatively lower in the assessment of stricture length.
Priyadarshi et al. found a similar sensitivity (77.22%) and specificity (85.33%) of RUG in the determination of length of strictures in India using intraoperative findings as gold standard. Maciejewski and Rourke also found a 72% sensitivity and 75% specificity of the RUG in the management of strictures. The above observation is relatively lower to the sensitivity (88.9%) and specificity (94.9%) of sonourethography in the determination of stricture length by Shahsavari et al. or a sensitivity (98.1%) and specificity (90.5%) found by Heinenreich. The observed differences in sensitivity and specificity of retrograde urethrography and sonourethrography in the determination of length of stricture may be due to absence of magnification on sonourethrography as well as use of sonographic calipers in the measurement of the stricture length. Magnetic resonance urethrography was evaluated by Rastogi et al. in 2016. A sensitivity of (95%) and specificity (91.7%) was found in the determination of length of strictures. The difference between the sensitivity of magnetic resonance urethrography and that of RUG in the management of strictures may be due to the better delineation of the tissues (spongiofibrosis) on magnetic resonance imaging as compared to RUG.
| Conclusion|| |
RUG as a gold standard in the management of urethral strictures has an overall high accuracy in diagnosis. It has a higher sensitivity and specificity for the determination of site and number of strictures as compared to length of stricture that is more affected by magnification and techniques in contrast administration. This should be considered during procedure as well as during interpretation of images. Adherence to the required techniques will provide a good assessment of the strictures. In situations where better assessment of the length of stricture and periurethral fibrosis is required, a sonourethrography may be used as adjuncts. Magnetic resonance urethrography may be a substitute, if available.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]