Abstract

Background:
Oronasal fistulas (ONFs) present significant therapeutic challenges in veterinary medicine, particularly in patients with comorbidities, such as chronic kidney disease. This case report demonstrates an innovative bioengineered approach for ONF repair in Felis silvestris that combines autologous biomaterials with microbiome analysis.

Case Description:
A 15-year-old male European wildcat with a chronic traumatic ONF (11 × 8 mm) and concurrent International Renal Interest Society Stage 2 chronic kidney disease received a customized implant composed of autologous platelet-rich fibrin (PRF), bone marrow aspirate, and a 3D-printed polyethylene glycol diacrylate (PEGDA) scaffold. PEGDA was selected for its high biocompatibility and rapid photopolymerization. Healing was monitored via computed tomography imaging and 16S rRNA sequencing. The results demonstrated significant microbial dysbiosis post-injury (Shannon index: 5.2 ± 0.3 vs. 3.1 ± 0.4; p < 0.05), with opportunistic pathogen enrichment (Enterococcus faecalis: 0.5% → 12.8%). Antibiotics reduced the bacterial load by 99.9% (p < 0.001) but did not improve the closure rate (p = 0.89), underscoring the mechanical role of the scaffold.

Conclusion:
The bioengineered implant facilitated complete mucosal integration and osteoconduction at the 10-month follow-up, demonstrating promise for complex ONF repair. However, the single-case design limits the generalizability.

Key words: Oronasal fistula; Felis silvestris; Tissue engineering; Oral microbiome; Platelet-rich fibrin; 3D bioprinting.