Bioactive materials for male urethral repair: a bibliometric and knowledge-mapping analysis

Male urethral strictures and defects are still difficult to reconstruct. Biomaterial-based repair offers an alternative to autologous grafts, but the field’s evidence structure has not been mapped systematically. Here we combine Web of Science Core Collection records (inception to December 2025), analyzed with VOSviewer, CiteSpace and Bibliometrix, with a five-level grading of clinical translation for each material category. Between the 1990s and 2025, work in the field progressed from inert mechanical substitutes to bioactive platforms and then to layered composite systems; materials took on complementary roles in support, signaling, delivery, shaping and regenerative control rather than replacing one another. Bibliometric heat did not track clinical readiness: 3D printing and exosomes were among the most prominent emerging nodes, although they remained largely preclinical, whereas small intestinal submucosa (SIS), acellular dermal matrix (ADM) and MatriStem carried comparatively stronger clinical evidence. This gap may reflect misalignment between the endpoints used by clinical and materials research. A layered composite, combining a degradable load-bearing skeleton, a natural extracellular matrix or hydrogel, and cells or exosomes shaped to the individual defect, may be worth pursuing if unified endpoints, large-animal validation in long defects and manufacturing standards are established. These results provide a framework for prioritizing materials and planning clinical translation.