Mineralized collagen biomaterial for reconstruction of cranial bone defects and its clinical applications

Abstract

Event Abstract Back to Event Mineralized collagen biomaterial for reconstruction of cranial bone defects and its clinical applications Zhiye Qiu1, 2, Tianxi Song2*, Yuqi Zhang3 and Xiumei Wang1 1 Tsinghua University, School of Materials Science and Engineering, China 2 Beijing Allgens Medical Science and Technology Co., Ltd., China 3 Yuquan Hospital, Tsinghua University, Department of Neurosurgery, China Introduction: Cranial bone defects result from congenital malformation, trauma, tumor, as well as produced by trephination in craniotomy are common symptoms in neurosurgery. Such defects should be repaired appropriate methods, in order to provide biomechanical stability for the skull, protect the brain, and achieve cosmetic results. Metals, bioceramics and polymers were tried to be used for repairing cranial defects, however, many disadvantages induced by these materials limited their clinical outcomes[1]. Especially for those pediatric patients with growing cranial bone, titanium mesh or polyetheretherketone restrict the growth of the cranial bone and result in high risk of malformation of the skull. Therefore, a biodegradable and osteoconductive biomaterial is required for the reconstruction of cranial bone defects[2]. Materials and Methods: Mineralized collagen was prepared by an in vitro biomimetic mineralization process. Briefly, calcium and phosphorous salts were added into acidic collagen solution, respectively; then the pH value and temperature were adjusted to form mineralized collagen deposition; after washing and freeze-drying, mineralized collagen biomaterial with the same chemical composition and microstructure to the nature bone matrix was obtained. Such mineralized collagen could be fabricated into many bone grafts, such as burr-hole plug, trepanation gap filling strip, as well as patient specific irregular implant according to CT scanning data of the patient. Phase composition and chemical structure were characterized by XRD and FTIR. Clinical outcomes of cranial bone defect reconstructions were evaluated by plain radiographs and CT scanning at the 6th and 12th month post-operation. Results and Discussion: For each patient, there were no inflammatory responses, itching, or exudation at the surgical sites, and the wounds healed well. The defects implanted with mineralized collagen biomaterials healed well. As shown by Figure 1, bone mineral density gradually increased and approximated surrounding host bone. However, the defects as the blank control without any implants unchanged during the follow-up period. Mineralized collagen is the fundamental structural unit of many connective tissues, including bone, the biomimetic mineralized collagen material therefore has the same chemical composition and microstructure to the natural bone[3]. Animal experiments demonstrated that the mineralized collagen could be gradually substituted by newly regenerated bone tissues. For the reconstruction of cranial bone defect, mineralized collagen biomaterial serves as a scaffold for bone regeneration induced by dura matter. Conclusion: Mineralized collagen biomaterial has good biodegradability and osteoconductivity. Clinical outcomes demonstrated mineralized collagen implants promoted bone reconstruction of cranial defects, without any adverse responses. National Basic Research Program (973 Program) of China (2011CB606205); ‘Twelfth Five-Year’ National Science and Technology Support Program (2012BAI17B02) funded by the Ministry of Science and Technology of China; National Natural Science Foundation of China (21371106, 51402167)