Paediatric calvarial healing and synthetic materials for its reconstruction.
Degree: MS, Department of Surgery, 2016, McGill University
Background:Large pediatric skull defects are challenging to the plastic surgeon. Bone grafts remains the standard of care, however, donor site morbidity remains a problem. Alloplastic materials offer advantages in comparison to bone grafts, they can precisely replicate missing parts with unlimited quantities. However, there are several material-specific disadvantages. The search for the ideal alloplastic material have been going for decades, and yet not found. Degradable ceramic bone graft substitutes (Monetite) have been preclinically proven in long bone healing. We hypothesize that Monetite could serve an ideal implant for cranial defects in children by stimulating bone repair while accommodating growth of the skull. Due to the scarcity of experiments on materials that may impede skull growth, there appear to be no animal models that take into account the growing skull. Methods: 1) Manuscript one:Use of Synthetic Materials in Paediatric Craniofacial Skeleton: A Review of Literature. A search was conducted in Pubmed/ Medline/Embase for alloplastic materials used in the pediatric population. Two reviewers extracted the data separately. In addition to demographic data, pre-operative pathology, defect size, complications, and follow-up time were extracted. 2) Manuscript two: Novel Model for Critical-Size Calvarial Defects in Growing Rabbits. Rabbits with a mean age of 8.5 weeks, and a weight of 1.6 kg were used. Two rabbits had bilateral cranial defects with the recommended size utilized in adults (15 mm diameter). The other 4 rabbits had one large central defect that 15x25 mm in size. Animals were sacrificed at 8 weeks postoperatively and the calvaria were removed for histological analysis. Calvarial CT was done prior sacrificing. 3) Manuscript three: Spherical Granules For Bone Healing Of Critical-Size Cranial Defects In Growing Rabbits. Critical size cranial defects were created in 12 young New Zealand white rabbits. Two defects were left without any implants as control. High porosity monetite granules filled four defects, high porosity monetite with silicon sheet in 3, and low porosity monetite in 3. CT imaging and cephalometric analysis were performed. Results: 1) Manuscript one: 55 articles met the inclusion criteria involving 4276 patients. In 73.9% of patients, absorbable materials were used. The mean age was 3.28 years, but was different between groups of materials used. Craniosynostosis being the most common material used. The rate of any complication was found to be 7.06 % with highest being in metals. 2) Manuscript two: Control group showed complete osseous consolidation of all 4 defects. However Group 2 no complete osseous consolidation of the calvaria was appreciated. 3) Manuscript three: Critical sized defects in the control group demonstrated persistent defects. Granule migration from the defect in the high porosity monetite group limited the bone/implant interface. Bony ingrowth improved when silicone sheet was applied, despite its improvement, the low porosity monetite group showed a higher rate of…
Advisors/Committee Members: Jake Barralet (Internal/Supervisor), Mirko Gllardino (Internal/Cosupervisor2).