Presentation Authors: AKIO HORIGUCHI*, Saitama, Japan, HIROMI EDO, Tokyo, Japan, SHIGEYOSHI SOGA, RYUICHI AZUMA, MASAYUKI SHINCHI, TOMOHIKO ASANO, KEIICHI ITO, HIROSHI SHINMOTO, Saitama, Japan
Introduction: Excision and primary anastomosis (EPA) is the gold standard management for traumatic bulbar urethral stricture due to straddle injury. Its complexity differs widely according to the degree of spongiofibrosis and the periurethral changes but cannot be predicted by conventional urethrography. Magnetic resonance imaging (MRI) has recently emerged as a modality enabling more accurate assessment of post-traumatic anatomy. We herein assessed the association of preoperative MRI findings and the complexity of EPA for traumatic bulbar urethral strictures.
Methods: 104 male patients with traumatic bulbar urethral stricture who underwent urethrography and MRI of the pelvis at least 3 months after injury and, subsequently, EPA between December 2010 and July 2018 were retrospectively analyzed. MRIs were reviewed by two radiologists experienced in urologic MRI and blinded to any clinical parameters. The MRI findings evaluated were continuity of tunica albuginea of corpus spongiosum, presence of a periurethral fistula, and length of spongiofibrosis. Disruption of corpus spongiosum was defined as continuity of the outline of its tunica albuginea being lost and replaced by scarring. EPA was performed in stepwise fashion. After bulbar urethral mobilization and transection through the site of stricture, the surgeon tried to find the proximal urethral end and evaluate the urethral tension to the anastomosis; corporal splitting was used only when the proximal urethral end could not be found or urethral tension was observed.
Results: On MRI, corpus spongiosum was disrupted in 60 patients (58%) and periurethral fistula was found in 23 (22%). The mean length of spongiofibrosis on MRI (14.9 mm) considered for resection was significantly greater than the stricture length measured by urethrography (9.6 mm, mean difference = 5.2 mm, p < 0.0001). The operative time correlated with the length of spongiofibrosis on MRI (r = 0.21, p = 0.03). The mean operative time in patients with fistula on MRI (173 minutes) was significantly longer than that in patients without fistula (157 minutes, p = 0.04). Corporal splitting was required in 41 patients (39%). The fraction requiring corporal splitting in patients with disrupted spongiosum (31 of 60, 52%) was significantly greater than that in patients without disrupted spongiosum (10 of 44, 23%, p = 0.003).
Conclusions: MRI can provide information that is useful for predicting the complexity of EPA for traumatic bulbar urethral stricture and cannot be obtained by conventional urethrography.