ESTABLISHING FREEZE DRYING PROCESS FOR CORTICAL AND CANCELLOUS BONE ALLOGRAFT CUBES

@#Freeze drying is a dehydration method to dry bone under freezing environment, enabling removal of water with no or minimial effects on bone strength and durability. Larger size bones obviously require longer freeze drying time to reduce water content to the required level for long term storage at room temperature. For small size bone cubes or chips, it is a normal practice to pool cortical and cancellous bones for freeze drying. The study was aimed at determining if different type of bones of the same size influence the drying time. Human bone cubes of 10 mm x 10 mm x 10 mm were prepared from cortical bone of tibiae and cancellous bone from femoral heads. The bone cubes were freeze dried to reduce water content to less than 6%. Moisture content was monitored using gravimetric method.Weight and density of cortical bone were significantly higher than cancellous bone despite of having similar small size (p<0.05). Cortical bones (density 2.05 ± 0.35 g/cm3) with initial water content of 10.93% required 5 hours to freeze dry, while cancellous bone cubes (density 0.72 ± 0.44 g/cm3) with initial water content of 78.95% required only 1.87 hours. This study confirmed that the structure hence density of human bone cubes determine the freeze drying time. Therefore in the standard operating procedure for freeze drying of bone allograft cubes, high density cortical bone cubes and low density cancellous bone cubes must be freeze dried separately despite being of similar small size

Knowledge on Bone Banking among Participants in an Orthopaedic Conference: A Preliminary Survey

Despite increasing use of bone graft in Malaysia, there was still lack of data to quantify knowledge level on bone banking among orthopaedic community who are involved in transplantation related work. Therefore, a survey on awareness in tissue banking specifically bone banking, usage and choice of bone grafts was conducted. From 80 respondents, 82.5% were aware about tissue banking however only 12.5% knew of the existence of tissue banks in Malaysia. Femoral head was the bone allograft most often used as a substitute to autograft. Only 34.8% respondents preferred irradiated bone grafts whilst 46.9% preferred nonirradiated, indicating the need to educate the importance of radiation for sterilising tissues. Exhibition was the most preferred medium for awareness programme to disseminate information about bone banking in the orthopaedic community. The professional awareness is necessary to increase the knowledge on the use of bone graft, hence to increase bone transplantation for musculoskeletal surgeries in the country.

Glycerol preserved bovine pericardium for abdominal wall reconstruction: experimental study in rat model

The aim of this study was to evaluate bovine pericardium surgical patch in rat model. Bovine pericardial sacs collected from local abattoir were cleaned, disinfected and cut into pieces of 3 by 2.5cm and preserved in 99.5% glycerol. Full thickness abdominal wall defects of 3 by 2.5 cm were created in 30 adult male Sprague Dawley rats and repaired with glycerol preserved pieces. The rats were serially sacrificed in a group of six rats at 1,3,6,9 and 18 weeks post-surgical intervals for morphological and tensometeric study. Macroscopically, no mortality or postoperative surgical complications was encountered except slight adhesions between implanted grafts and some visceral organs in 10% of the rats. Microscopically no calcification or foreign body giant cell formation was found in the explanted grafts. The implanted grafts were replaced gradually with recipient tissue, which made mainly of dense collagenous bundles. The healing strength between the implanted grafts and the recipient abdominal wall was gradually increased with time. The results of this study showed that glycerol preserved bovine pericardium act as scaffold for transformation into living tissue without clinical complications such as that associated with prostheses.