Transperineal anastomotic urethroplasty with distal transection versus proximal transection: How to predict?

To evaluate the pubourethral stump angle (PUA) to determine the site of urethral transection during transperineal anastomotic urethroplasty (TAU). Patients diagnosed with pelvic fracture urethral distraction defect who underwent preoperative magnetic resonance (MR) urethrography and were treated with TAU between June 2019 and December 2021 were retrospectively reviewed. According to the site of urethral transection during TAU, patients were classified into proximal and distal groups receiving TAU with proximal and distal transection, respectively. The demographic and clinical data were recorded. The PUA was measured on sagittal T2-weighted MR urethrography. The relationship between the site of urethral transection and PUA was analyzed. Sixty-seven patients were included. Forty-one and 26 patients were included in the proximal and distal groups, respectively. Finally, the success rates in the proximal and distal groups were 95.1% and 92.3%, respectively. The PUAs were 123.7° ± 14.6° and 86.5° ± 9.8° (p = 0.005), respectively. The curves for the 2 groups intersected between 90° and 110°. The scribing effects at 90°, 100°, and 110° in the 2 groups were compared in detail. Compared with 90° and 110°, 100° had the highest sensitivity as the demarcation line. In the treatment of pelvic fracture urethral distraction defect, the PUA on MR urethrography is an objective and valid parameter for evaluating the site of urethral transection during TAU. A PUA >100° indicates that proximal transection should be preferentially attempted.