Introduction: Male urethral strictures (especially bulbar) are most commonly idiopathic. It is assumed that these strictures are related to trauma. However, many patients with idiopathic urethral strictures do not recall any specific trauma and there may be other genetic, systemic or immunologic factors involved. Our purpose is to compare clinical factors between patients with idiopathic and traumatic urethral strictures.

Methods: A retrospective review of patients undergoing bulbar urethroplasty with either idiopathic or traumatic etiology at the University of Alberta from August 2003 to May 2019. Patients with previous urethroplasty or unrelated etiologies were excluded. Patients with acute urethral trauma were excluded, however, patients with a history of subacute or repetitive perineal trauma were included in the analysis.

Results: 832 patients (mean age 43.6±15.0) were identified and analyzed. 584 patients (70.2%) were diagnosed with an idiopathic etiology. Rates of prior endoscopic treatment (2.4 vs 2.6; p=0.65) and age (43.9 vs. 43.0 years; p=0.41) were similar between the idiopathic and traumatic stricture groups. The idiopathic group when compared to the traumatic etiology, had strictures which were longer (3.8 vs. 3.3 cm, p=0.03), were less likely to be smokers (12.5% vs. 22.6%, p<0.001), and more likely to be obese (BMI >35) (14.0% vs. 8.1%, p=0.02). There was a significant difference (p<0.0001) in urethoplasty technique between the groups (idiopathic stricture: 70.2% onlay with buccal mucosa; traumatic structure: 52.0% anastomotic urethroplasty). Both idiopathic and traumatic stricture groups had similar rates of diabetes (9.9% vs. 7.3%, p=0.22) and COPD (1.7% vs. 1.6%, p=0.92).

Conclusions: There are some key differences between idiopathic and traumatic bulbar urethral strictures. Further investigation of systemic, immunologic, metabolic, or wound healing factors may be warranted to elucidate the nature of men with idiopathic urethral strictures.