|Year : 2020 | Volume
| Issue : 2 | Page : 132-136
Role of sonourethrography in the evaluation of anterior urethral stricture: A 1-year hospital-based observational study
Bibi Ayesha I. Pathan1, SI Neeli2, DB Udoshi1
1 Department of Radio-Diagnosis, J.N.M.C., Belagavi, Karnataka, India
2 Department of Urology, J.N.M.C., Belagavi, Karnataka, India
|Date of Submission||06-Jan-2020|
|Date of Acceptance||11-Mar-2020|
|Date of Web Publication||23-Jun-2020|
Dr. Bibi Ayesha I. Pathan
H No 34/155, Shah Kutir, Cariappa Colony, Nanawadi, Belagavi - 590 009, Karnataka
Source of Support: None, Conflict of Interest: None
CONTEXT: Urethral stricture is a pathology involving the anterior urethra. The parameters to the surgical approach are precise measurement of stricture length and spongiofibrosis. Retrograde urethrography (RGU) is considered as the gold standard investigation. Its limitations are poor definition of stricture length and the detection of spongiofibrosis. Sonourethrography (SUG) detects stricture and accurately measures length and spongiofibrosis.
AIM: The aim of this study is to compare the efficacy of SUG in the evaluation of anterior urethral strictures.
SETTINGS AND DESIGN: The study design involves hospital-based 1-year observational study.
SUBJECTS AND METHODS: One-year prospective observational study was conducted in the Department of Radio-Diagnosis at the KLE'S Dr. Prabhakar Kore Hospital and MRC, Belagavi. Thirty patients underwent RGU and SUG. Sensitivity, specificity, positive, and negative predictive values of SUG were calculated. Unpaired t-test was used to determine the length of the anterior urethral stricture. The values were compared with RGU and intra-operative results. The percentage of patients detected to have spongiofibrosis was computed.
STATISTICAL ANALYSIS USED: Mean, standard deviation, and unpaired t-test were used for statistical analysis.
RESULTS: The sensitivity and specificity of sonourethrogram as compared to retrograde urethrogram was found to be 92% and 100%, respectively, with positive and negative predictive values of 100% and 71.43%, respectively. Intra-operative stricture length correlated better with SUG with the determination of spongiofibrosis being an advantage.
CONCLUSION: RGU is the best imaging modality, but SUG also provides similar results with benefits such as precise measurement of stricture length and degree of spongiofibrosis.
Keywords: Ascending urethrogram, sonourethrogram, stricture
|How to cite this article:|
Pathan BA, Neeli S I, Udoshi D B. Role of sonourethrography in the evaluation of anterior urethral stricture: A 1-year hospital-based observational study. Indian J Health Sci Biomed Res 2020;13:132-6
|How to cite this URL:|
Pathan BA, Neeli S I, Udoshi D B. Role of sonourethrography in the evaluation of anterior urethral stricture: A 1-year hospital-based observational study. Indian J Health Sci Biomed Res [serial online] 2020 [cited 2021 Jun 16];13:132-6. Available from: https://www.ijournalhs.org/text.asp?2020/13/2/132/287384
| Introduction|| |
Urethral stricture is an obstructive pathology involving the anterior urethra., Retrograde urethrography (RGU) is considered as the gold standard investigation being 91% sensitive.
RGU is a two-dimensional (2D) investigation. The appearance of stricture depends on stress on urethra and posture of the individual while injecting contrast. It requires right and left oblique views with radiation exposure of 1–2 mSv.,, Limitations of RGU are the poor definition of stricture length and spongiofibrosis.
Sonourethrography (SUG) is a 3D technique with the advantages of being radiation-free and easy repeatability.
Thus, the study aims to determine the efficacy of SUG in the evaluation of male anterior urethral strictures.
| Subjects and Methods|| |
All patients with suspected anterior urethral pathology, who are fulfilling the eligibility criteria and are referred for radiological imaging to the Department of Radio-Diagnosis at the KLE'S Dr. Prabhakar Kore Hospital and MRC, Belagavi, were included in the study. These patients are subjected to RGU and SUG to detect stricture, measure its length, and the degree of spongiofibrosis.
Patient information is stored in the computer and patient data entry books. These hospital records are the source of data in this study.
Methods of data collection
The study design involves prospective observational study.
The study was conducted 1 year, January 1, 2018–December 31, 2018.
The prevalence of urethral stricture disease in most of the studies done is very less (0.3%–0.6%). Therefore, the study comprised all the patients presenting with signs and symptoms involving urethral outflow tract pathologies, who were referred to the Department of Radio-Diagnosis for RGU and SUG during the study period.
Universal sampling method was used.
All male patients presenting with signs and symptoms of urethral outflow tract pathologies were included.
- eNonconsenting patients
- History of allergy to the contrast material used in retrograde urethrogram
- Patients with watering can perineum
- Patients with Fournier's gangrene
- Patients with posterior urethral stricture.
Ethical clearance was obtained. The included patients gave written informed consent for both RGU and SUG. A detailed history was noted in the form of a systematic pro forma regarding patient name, age, sex, presenting complaints, and past medical/surgical history.
While performing retrograde radiography, the urethra was moderately stretched by applying external stress and syringe with a cannula tip was utilized for injecting contrast medium. The patient was placed in the supine position and the dependent thigh was acutely flexed while the pelvis is tilted obliquely to 45°. Under the guidance of radiographic imaging, 10.0–20.0 cc of contrast agent was injected (meglumine or sodium diatrizoate, 50%–60% in adults and 30% in children). During injection of contrast, images were obtained. Precaution was taken to prevent the entry of air bubbles into the urinary tract during the procedure. The stricture was identified with its location, and the length of the narrowed portion was calibrated by using electronic caliper.
Dynamic RGU is called so because the urethra is visualized during the procedure under fluoroscopic guidance. Topical anesthetic agents mixed with lubricating agents can produce mucosal edema and are less beneficial during the procedure.
Role of sonographic imaging for the study of male urethral stricture was first done in 1985 by McAninch et al. Earlier sonourethrographic images were also obtained by Wagner and Merkle in 1988. Seven to 12 MHz high-frequency linear transducer was used during the procedure. Sonographic imaging was done by placing the transducer directly on the ventral or dorsal aspect of the penis, scrotum, and perineum. Saline or sterile gel was repeatedly injected by utilizing catheter tip syringe, and the images were simultaneously obtained. Imaging is done in a systematic manner, beginning from the base of the penis up to glans penis. Approximately 10–15 ml saline was needed for the adequate and precise study of the anterior urethra. Images were obtained in both planes. Parameters such as location, length, and the number of strictures are identified. The degree of spongiofibrosis can also be identified. The entire SUG can be done by an experienced radiologist in approximately 10–15 min.
Sensitivity, specificity, positive predictive value, and negative predictive value of both the procedures were determined. The length of stricture was evaluated by unpaired t-test. SUG could also detect extra-luminal pathology and thus help in the identification of the degree of spongiofibrosis, which is a helpful guide for surgical management.,
| Results|| |
Thirty patients referred for RGU and SUG were prospectively evaluated in this study.
Out of 25 patients detected to have strictures by RGU, SUG could detect in 23 patients. Thus sensitivity, specificity, positive, and negative predictive values are 92%, 100%, 100%, and 71.43%, respectively [Table 1].
|Table 1: Detection of stricture by sonourethrography in comparison to retrograde urethrography|
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Out of 25 patients detected to have strictures by intraoperative findings, sonourethrogram could detect in 23 patients. Thus sensitivity, specificity, positive, and negative predictive values are 92%, 100%, 100%, and 71.43%, respectively [Table 2].
|Table 2: Detection of stricture by sonourethrography in comparison to intraoperative findings|
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Out of 25 patients detected to have strictures by intraoperative findings, RGU could detect strictures in all 25 patients. Thus sensitivity, specificity, positive, and negative predictive values are 100% each [Table 3].
|Table 3: Detection of stricture by retrograde urethrography in comparison to intraoperative findings|
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There was a significant difference in the mean length of stricture observed by RGU and sonourethrogram (P = 0.0004). Thus there was no significant correlation in the measurement of the length of stricture by both procedures [Table 4].
|Table 4: Determination of length of stricture by retrograde urethrography and sonourethrogram|
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There was no significant difference in the mean length of stricture observed by sonourethrogram and the intraoperative result (P = 0.93). Thus, the measurements obtained by sonourethrogram correlated well with surgical results [Table 5].
|Table 5: Determination of length of stricture by sonourethrogram and intraoperative finding|
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There was a significant difference in the mean length of stricture observed by RGU and intraoperative result (P = 0.0003). Thus, measurements on RGU did not correlate well with intraoperative results [Table 6].
|Table 6: Determination of length of stricture by retrograde urethrography and intraoperative finding|
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Sonourethrogram could detect spongiofibrosis accurately in 22 of 23 patients (95.6%), i.e., except for one case, in which the sonourethrogram predicted as moderate degree spongiofibrosis while intraoperative it was found to be severe [Table 7].
|Table 7: Degree of spongiofibrosis by sonourethrography and intraoperatively|
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| Discussion|| |
Anterior urethral stricture is one of the common conditions presenting to the Urology Department. Retrograde urethrogram was first performed in 1910 by Cunningham and is now considered as a gold standard imaging modality for the preoperative diagnosis of strictures affecting anterior urethra.,,
SUG is another diagnostic modality for the detection of anterior urethral strictures.,, It was first performed by Morey and McAninch. It has other advantages in diagnosis such as accurate detection of stricture length and degree of spongiofibrosis, which is a drawback of RGU.
In this study, age is not a determining factor as the etiology of stricture is not age dependent. The mean age of patients in this study was 49.33 years.
In the current study, sonourethrogram could detect strictures in 23 patients, whereas 25 patients were detected by RGU [Figure 1] and [Figure 2]. In our study, both sonourethrogram and RGU could detect five patients not having stricture correctly. Thus sonourethrogram was 92% sensitive and 100% specific. In our study as compared to RGU, the positive predictive value was 100% and negative predictive value was 71.43%.
|Figure 1: Sonourethrographic appearance of stricture in proximal bulbar urethra (longitudinal view)|
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|Figure 2: Retrograde urethrographic imaging of stricture in proximal bulbar urethra|
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In a prospective study conducted by Akpayak et al. in 2012 on 60 patients, the sensitivity of SUG was found to be 94%. According to a study performed by Heidenreich et al., the sensitivity and specificity of SUG in the detection of urethral stricture were 98% and 96%, respectively. In another study conducted by Ravikumar BR et al. in 2015, specificity, positive predictive, and negative predictive values were found to be 100%.
In the current study, out of 25 patients having stricture intraoperatively, SUG could detect 23 patients. Hence, the sensitivity of SUG was 92%. In our study, sonourethrogram could detect five patients not having stricture, which correlated intra-operatively. Thus, the specificity of sonourethrogram is 100%. In our study, the positive and negative predictive values of sonourethrogram as compared to intraoperative results were 100% and 71.43%, respectively.
In the current study, out of 25 patients having stricture intraoperatively, RGU could detect 25 patients. Thus the sensitivity, specificity, positive, and negative predictive values of RGU as compared to intraoperative results were 100%.
In the current study, the mean stricture length as detected by RGU was 1.06 (standard deviation [SD]: 0.56) and by sonourethrogram was 1.70 (SD 0.56) (P = 0.0004). Thus, there was significant difference in the stricture length detected by RGU and sonourethrogram.
On the other side, according to the current study, the mean stricture length as detected by sonourethrogram was 1.70 (SD 0.56) and during the surgery, the mean length was found to be 1.69 (SD 0.55) (P = 0.93). Thus, there was no significant difference in the stricture length detected by sonourethrogram and the intraoperative results. From the present study, it can be concluded that the stricture length correlated better with SUG as compared to RGU.
In a study conducted by Srinivas et al. published in 2018, the median stricture length by retrograde urethrogram, sonourethrogram, and intraoperative results were 21.0 mm, 30.5 mm, and 32.0 mm, respectively. Thus, their study concluded that there was a better correlation of intra-operative stricture length with sonourethrogram findings, and there was the underestimation of stricture length by retrograde sonourethrogram. Similar results were obtained by Gupta et al. Akpayak et al. also concluded that SUG was superior in the determination of stricture length.
In the present study, the most common site of stricture was bulbar urethra (44%) and the next common was bulbomembranous junction (36%). According to another study by Srinivas et al., the most common site of stricture was also located in the bulbar urethra. The reason may be because penile urethra takes a bent to form the bulbar urethra, thus making it prone to both iatrogenic and noniatrogenic injuries.
In the present study, out of 25 patients having stricture intraoperatively; sonourethrography could detect 23 patients. Among the 23 patients detected by SUG, 01 (4.34%) had mild, 08 (34.78%) had moderate, and 14 (60.86%) had a severe degree of spongiofibrosis. Among the 25 patients having stricture intraoperatively, 02 (8%) had mild, 08 (32%) had moderate, and 15 (60%) had a severe degree of spongiofibrosis. SUG findings correlated well with the intra-operative findings of the degree of spongiofibrosis except for one case, in which the sonourethrogram predicted as moderate degree spongiofibrosis while intraoperative it was found to be severe. Thus, SUG could accurately detect stricture in 95.6%. According to a study by Srinivas et al., SUG was 100% sensitive.
From the present study, it can be concluded that though RGU is the gold standard imaging modality in the detection of male anterior urethral strictures, SUG can also provide similar results with benefits such as precise measurement of stricture length and degree of spongiofibrosis.
| Conclusion|| |
Urethral obstructive pathologies are one of the common problems presenting to the urosurgeon. Ascending urethrography is the gold standard investigation which has high sensitivity and specificity in identification of anterior urethral strictures. Sonourethrography has extra advantage of identifying the degree of spongiofibrosis and precisely measuring the length of stricture. Thus the study concluded that though radiographic imaging is the best imaging modality available, sonourethrography can also provide similar results with additional benefits like precise measurement of length of stricture involving the anterior urethra (especially the bulbar urethra) and severity of spongiofibrosis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]