Hard-flaccid syndrome: a systematic review of aetiopathophysiology, clinical presentation and management.

Hard-flaccid syndrome (HFS) is a rare condition characterised by a semi-rigid penis in the flaccid state, often accompanied by perineal and urinary symptoms. It may also induce psychological distress, which can exacerbate physical symptoms, creating a vicious cycle. There is currently no standardised treatment for HFS, and management typically focuses on addressing both the underlying causes and presenting symptoms. A systematic review of the literature identified 8 eligible studies. Although the exact aetiopathogenesis remains unclear, it is hypothesised that an initial penile trauma may trigger a cascade of neurovascular and inflammatory events. The associated psychological impact may further perpetuate symptoms, reinforcing the cycle of dysfunction. Common symptoms include perineal pain, urinary disturbances, and erectile and ejaculatory dysfunction. Evaluation involves a comprehensive clinical history, relevant blood and radiological investigations to exclude other pathologies, and the use of symptom questionnaires. Reported treatments include phosphodiesterase-5 inhibitors, anxiolytics, low-intensity shockwave therapy, pelvic floor physical therapy, spinal surgery, and biopsychosocial therapy. Management should be individualised, with a focus on relieving symptoms and breaking the self-perpetuating cycle of HFS. Further evidence-based studies are needed to better understand the pathophysiology of HFS, as well as to develop clear diagnostic criteria and management guidelines.