Grants Funded

Abstract
Large skull defects in pediatric patients can result from trauma, infection, birth defects, or tumor resection, and often represent a significant reconstructive challenge to plastic surgeons for several reasons. Removal of sufficient bone to fill the defect from a rib or hip in the same patient (autograft) is usually not feasible and the use of dead bone from an unrelated donor (allograft) carries the risk of infection and does not stimulate new bone formation adequately. Grafts made from synthetic materials do not grow with the patient and often do not integrate with the patient's own bone. For these reasons there is a pressing clinical need to develop new approaches for filling large defects in the pediatric skull. Our project is built on the hypothesis that a bone-like material called "monetite" can be used as an implant to induce bone formation in the patient's body - either on the skull or elsewhere under the skin by a process called "heterotopic ossification". This implant, along with the newly grown bone, may then be excised and used to treat skull defects. To complement monetite - a bioceramic that has demonstrated its ability in our preliminary work to promote bone deposition - the implant can also be mixed with bone marrow (taken from the same patient) as an alternative strategy. Over the long term, the objective of our research is to develop a material that can be safely and effectively used to fill large defects in the skulls of pediatric and adult patients, and that can eventually be replaced by the patient's own bone.
We will test the hypothesis using a pre-clinical rat model in which part of the skull of is removed to mimic a clinical craniotomy, using two main different approaches for bone repair: 1- Induction of new bone in a skull defect and on intact skull bone, and 2- Induction of new bone in a pocket underneath the skin on the back. The implants will be kept in place for a period of 8 weeks to allow for new bone growth, following which they will be excised and transplanted onto the skull defects, where they are kept for another 8 weeks to study healing. The structure, stability, and composition of the new bone will be assessed by micro computed tomography (micro-CT) and histological examination. The integration of the new transplanted bone into the recipient site will also be evaluated by micro-CT in addition to immunohistochemistry, and growth parameters will be measured by means of cephalometric analysis (CMA).

Biography
A native of Bahrain, Mohamed Abdulla obtained his medical degree in 2010 from the Arabian Gulf University, and was awarded a 1-year paid surgical internship by the Ministry of Health. Pursuing a keen interest in the field of plastic surgery, he then joined the surgery residency program at the Bahrain Defense Force Hospital. After completing his 2-year core surgery training, he moved to Canada where he is currently enrolled in a Master's program in Experimental Surgery at McGill University. Under the supervision of Professor Jake Barralet - a published expert in bone research and inventor of bone ceramics; and Dr. Mirko Gilardino - associate professor of surgery and director of the HB Williams Craniofacial and Cleft Unit at the Montreal Children's Hospital, Mohamed is currently studying the pathophysiology of craniofacial wound healing. His work mainly consists of creating a bone-specific biodegradable composite for the healing of pediatric skull defects, and refining techniques that allow for implant testing on animal models. After obtaining his Masters degree, Mohamed aims to join a plastic surgery residency program where he can further foster his passion for plastic surgery in general, and specifically - in the field of reconstructive craniofacial surgery. When not in the lab, Mohamed enjoys spending time with his lovely wife Mai and baby daughter Jena. He is also an avid guitarist, with a passion for 7-string guitars and progressive rock music of the seventies.