AUTHOR REPLY

There has been conflicting evidence about the influence of comorbidities on the outcomes of urethroplasty. In this homogenous cohort, we were able to show that cardiovascular risk factors do not seem to play a significant role in stricture recurrence. While we identified a drop in postoperative hemoglobin as a significant predictor of stricture-free survival, it is not our intent to advice liberal blood loss during these operations. Instead, we believe that thoughtfully ordered laboratory data might be beneficial to understand the underlying nature of the disease. The results of our study encourage further research on the pathophysiological background of urethral strictures. A major focus should be on microcirculation as a source of molecular inflammation and tissue alterations. This principle has already been evaluated in critical care, transplant, or plastic surgery as in indicator of sepsis, organ, or graft failure. In urethral strictures, Hughes et al. just recently demonstrated significant histopathological changes in tissue derived from urethral stenosis between radiated and nonradiated patients during urethroplasty for recurrent urethral stenosis. The authors developed a histopathologic grading system (eg, collagen density and organization, inflammation) in which vascular density of the tissue comprising the stenosis was quantified by number of capillaries per high power field, resulting in five different gradings. Additionally, our study group previously demonstrated the feasibility of histological analyses in redo-buccal mucosa graft urethroplasties. Preoperative evaluation of the oral donor site may help to identify additional risk factors for stricture recurrence. Prospective interdisciplinary (oral and maxillofacial surgery) studies investigating various histological and biochemical parameters of oral mucosa and dental status at our institution are underway. These efforts aim to understand and identify potential predictors of stricture recurrence on the histopathological and molecular level to improve surgical outcomes in the future.