CLINICAL APPLICATIONS OF BIOMATERIALS Original Research Elastomeric enriched biodegradable polyurethane sponges for critical bone defects: a successful case study reducing donor site morbidity Catarina Lavrador 1 • Ramiro Mascarenhas 2 • Paulo Coelho 3 • Cla ´udia Brites 4 • Alfredo Pereira 1 • Sylwester Gogolewski 5 Received: 24 June 2015 / Accepted: 8 January 2016 Ó Springer Science+Business Media New York 2016 Abstract Bone substitutes have been a critical issue as the natural source can seldom provide enough bone to support full healing. No bone substitute complies with all necessary functions and characteristics that an autograft does. Polyurethane sponges have been used as a surgical alternative to cancellous bone grafts for critical bone defect donor sites. Critical bone defects were created on the tibial tuberosity and iliac crest using an ovine model. In group I (control-untreated), no bone regeneration was observed in any animal. In group II (defects left empty but covered with a microporous polymeric membrane), the new bone bridged the top ends in all animals. In groups III and IV, bone defects were implanted with polyurethane scaffolds modified with biologically active compounds, and bone regeneration was more efficient than in group II. In groups III and IV there were higher values of bone regeneration specific parameters used for evaluation (P \ 0.05) although the comparison between these groups was not possible. The results obtained in this study suggest that biodegradable polyurethane substitutes modified with bio- logically active substances may offer an alternative to bone graft, reducing donor site morbidity associated with auto- genous cancellous bone harvesting. Graphical Abstract Bone substitutes have been a critical issue as the natural source can seldom provide enough bone to support full healing. No bone substitute complies with all necessary functions and characteristics that an autograft does. Polyurethane (PU) sponges have been used as a surgical alternative to cancellous bone grafts for critical bone defect donor sites. Critical bone defects were created on the tibial tuberosity and iliac crest using an ovine model. In group I (control-untreated), no bone regeneration was observed in any animal. In group II (defects left empty but covered with a microporous polymeric membrane), the new bone bridged the top ends in all animals. In groups III and IV, bone defects were implanted with polyurethane scaffolds modified with biologically active compounds, and bone regeneration was more efficient than in group II. In groups III and IV there were higher values of bone regeneration specific parameters used for evaluation (p <0,05) although the comparison between these groups was not possible. The results obtained in this study suggest that biodegradable polyurethane substitutes modified with biologically active substances may offer an alternative to bone graft and reducing donor si te morbidity, associated with autogenous cancellous bone harvesting. 1 Introduction The growing demand for bone substitutes has led to the development of intense research in this domain. Bone autografts alone could hypothetically be the solution since they are self-sufficient, but this is not always true: the harvesting of bone autografts often leads to significant donor site morbidity, with both major and minor compli- cations (8.6 and 20.6 %, respectively) [1, 2]. On the other hand, we are frequently faced with a lack of bone to fill in the voids. This brings us to the dilemma that no bone & Catarina Lavrador clavrador@uevora.pt 1 Institute of Mediterranean Agricultural and Environmental Science (ICAAM); School of Science and Technology (ECT), University of E ´ vora, E ´ vora, Portugal 2 Institute of National Agricultural and Veterinary Research (INIAV), Av. da Repu ´blica, Quinta do Marque ˆs, 2780-157 Oeiras, Portugal 3 Faculty of Dental Medicine, University of Lisbon, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal 4 Laborato ´rio de Tecidos Duros - Area of Dental Medicine, Faculty of Medicine, University of Coimbra, Av. Bissaya Barreto, Blocos de Celas, 3000-075 Coimbra, Portugal 5 PolyBiomat Consulting, Zielona Gora, Poland 123 J Mater Sci: Mater Med (2016)27:61 DOI 10.1007/s10856-016-5667-8