This study aims to measure the geometric parameters of urethral distraction defects in pelvic fracture urethral injuries (PFUI) using Magnetic resonance urethrography (MRU) and correlate them with intraoperative findings. We also compare MRU with Retrograde and Micturating Cysto-Urethrogram (RGU/MCU) and assess MRU’s added benefit in detecting recto-urethral and recto-vesical fistulas

Patients with PFUI presenting 3 or more months post-injury were evaluated using RGU, MCU, and MRU. Key geometric parameters—defect length, Pubourethral Vertical Distance (PUVD), Rectourethral Median Distance (RUMD), and Pubourethral Length (PUL)—were measured. Operative findings and various parameters to assess complexity of reconstruction were recored and correlated with preoperative findings

The mean operative time and blood loss were significantly higher in the pubectomy group (266 minutes and 340 ml) compared to the non-pubectomy group (176 minutes and 227 ml, p=0.003 and p=0.008, respectively), with two patients in the pubectomy group requiring transfusions. Pubectomy was performed in 35% of patients, where the mean urethral defect lengths measured by MRU and RGU/MCU were 3.5±1.3 cm and 3.8±1.2 cm, respectively. Distraction defects greater than 3.9 cm were more likely to require pubectomy. Additionally, a PUVD of <1.4 cm was predictive of the need for more extensive procedures (AUC 0.77). A RUMD of <0.975 cm was associated with a higher risk of recto-urethral fistula or rectal injury during surgery. In total, 25% of patients required additional procedures.

MRU provides a more accurate assessment of defect size, offering predictive value for the need for procedures like pubectomy. Parameters such as PUVD and RUMD also show strong predictive value for surgical complexity.