This is to report on the use of growing endoprosthesis, also known as lengthening prosthesis in the management of four patients in the paedriatic age group in the Orthopaedic Oncolgy Unit at University Malaya Medical Centre. These are custom made prosthesis, designed and made in India based on measured roentrograms. The ages of these patients vary from 6 to 13 years old. These are cases of Osteosarcoma and Ewing's sarcoma around the knee. This is the first time these custom made prosthesis have ever been used in Malaysia. We feel that this is a feasible option for limb salvage in the treatment of primary bone tumours in growing children.
We conducted a prospective study in order to audit our experience of repairing cranial defects using Methyl methacrylate. This included a total of 49 patients undergoing cranioplasty using methyl methacrylate, of which 45 were males and 4 females. The age of patients at the time of surgery ranged from 16 to 40 years old, with an average of 24 years. Malays were the majority (67%), followed by Chinese (23%) and Indian (10%). Cranial defects were mainly caused by motor vehicle accident (94%), while gunshot wounds, industrial accidents and tumours, each contribute 2%. Bone flaps were commonly removed during previous surgery related to traumatic subdural haemorrhage (33%), contusion (21%) and intracerebral haemorrhage (14%). The size of cranial defects ranged from 28 cm2 to 440 cm2, with an average of 201 cm2. Most had right sided (55%) and lateral defects [temporoparietal (52%) followed by temporal (16%), frontal (16%), frontotemporal (14%) and occipital (2%)]. Duration of surgery ranged from 70 to 275 minutes, with an average of 135 minutes. Nine of 12 patients (75%) with neurological disability had some improvement while 85% of symptomatic patients had symptoms improvement after cranioplasty. The infection rate in this series was 4%.
Hydroxyapatite powder was mechanochemically synthesized from calcium pyrophosphate (Ca2P2O7) and calcium carbonate (CaCO3) using a solid-state reaction. The two powders were mixed in distilled water, milled for 8 hours, dried and calcined at 1100 degrees C for 1 hour. The phase(s) formed was analyzed by x-ray diffraction (XRD). It was found that hydroxyapatite was not the only one formed. This result will be used as the starting point to produce a single-phase hydroxyapatite in terms of excess hydroxyl group in a mechanochemical reaction.
The present paper reports on the influence of sintering temperature on the porosity and strength of porous hydroxyapatite (HA). HA powder was first prepared by the sol-gel precipitation method using calcium hydroxide and ortho-phosporic acid. The fine HA powder, measuring <50 microm was then mixed into a slurry with the addition of binder agent, being a mixture of sago and PVA. A small amount of sodium dodecyl sulphate was also used as a foaming agent. Porous HA samples were then prepared via slip casting technique. The surface morphology of the sintered samples was observed under scanning electron microscopy at 20 kV and the compositions were determined via SEM-EDX. A universal testing machine was used to determine the compaction strength of the sintered samples.
A mixture with different compositions of HA and TCP were synthesize in this work by precipitation method using Ca(NO3)2 4H2 and (NH4)2HPO4 as the starting materials. A mixture with HA and TCP phases in different ratios were produced. The powders were sintered from 1000 degrees C to 1250 degrees C. The phase compositions of the mixtures were then studied via XRD. This work shows that the pH value determines the different phase compositions of the HA-TCP mixture. Chemical analyses were carried out by FTIR. The microstructure was observed under SEM.
Biomaterials intended for end-use application as bone-graft substitutes have to undergo safety evaluation. In this study, we investigated the in vitro cytotoxic effects especially to determine the mode of death of two hydroxyapatite compounds (HA2, HA3) which were synthesized locally. The methods used for cytotoxicity was the standard MTT assay whereas AO/PI staining was performed to determine the mode of cell death in HA treated L929 fibroblasts. Our results demonstrated that both HA2 and HA3 were not significantly cytotoxic as more than 75% cells after 72 hours treatment were viable. Furthermore, we found that the major mode of cell death in HA treated cells was apoptosis. In conclusion, our results demonstrated that these hydroxyapatite compounds are not cytotoxic where the mode of death was primarily via apoptosis.
Hydroxyapatite is the main component of the bone which is a potential biomaterial substance that can be applied in orthopaedics. In this study, the biocompatibility of this biomaterial was assessed using an in vitro technique. The cytotoxicity and genotoxicity effect of HA2 and HA3 against L929 fibroblast cell was evaluated using the MTT Assay and Alkaline Comet Assay respectively. Both HA2 and HA3 compound showed low cytotoxicity effect as determined using MTT Assay. Cells viability following 72 hours incubation at maximum concentration of both HA2 and HA3 (200 mg/ml) were 75.3 +/- 8.8% and 86.7 +/- 13.1% respectively. However, the cytotoxicity effect of ZnSO4.7H2O as a positive control showed an IC50 values of 46 mg/ml (160 microM). On the other hand, both HA2 and HA3 compound showed a slight genotoxicity effect as determined using the Alkaline Comet Assay following incubation at the concentration 200 mg/ml for 72 hours. This assay has been widely used in genetic toxicology to detect DNA strand breaks and alkali-labile site. The percentage of the cells with DNA damage for both substance was 27.7 +/- 1.3% and 15.6 +/- 1.0% for HA2 and HA3 respectively. Incubation of the cells for 24 hours with 38 microg/ml (IC25) of positive control showed an increase in percentage of cells with DNA damage (67.5 +/- 0.7%). In conclusion, our study indicated that both hydroxyapatite compounds showed a good biocompatibility in fibroblast cells.
The present study is aimed at finding the mutagenicity and cytotoxicity of dense form of synthetic hydroxyapatite (Source: School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia) in the blood of sheep. The biomaterial was implanted in the tibia of Malin, an indigenous sheep breed of Malaysia. Blood was collected from the sheep before implantation of the biomaterial, cultured and a karyological study was made. Six weeks after implantation, blood was collected from the same animal, cultured and screened for chromosome aberrations. The mitotic indices and karyological analysis indicated that the implantation of synthetic hydroxyapatite (dense form) did not produce any cytotoxicity or chromosome aberrations in the blood of sheep.
There has been, and is still, concern about the high elastic modulus of Ti alloys compared to bone. Any reduction in the Young's modulus value of the implant is expected to enhance stress redistribution to the adjacent bone tissues, minimize stress shielding and eventually prolong device lifetime. Dynamic Monte Carlo simulation is used to predict the gradual reduction in Young's modulus values between the bulk of Ti alloys and the modified surface layers due to Ca ion implantation. The simulation can be used as a screening step when applying new alloys and/or coatings.
In this work, nanometer HA crystals have been synthesized via wet chemical precipitation and characterized. This research studies how key synthesis parameters affect the size and phase purity of the produced HA. Characterization work was carried out using X-ray powder diffraction method and scanning electron microscopy for phase identification and particle sizing, respectively.
A study was conducted to investigate the effectiveness of freeze-dried bovine pericardium (FDBP) as a biomaterial in diaphragmatic herniorrhapy in dogs. Eight adult dogs were randomly selected and divided into two equal groups. In FDBP group, a diaphragmatic defect was induced and repaired with an identical size of FDBP. In the control group, a diaphragmatic wall was incised at three-side border creating a flap and sutured. Grossly, only mild intrathoracic adhesion was observed for most of the animals, and no herniation occured. Microscopically, the biomaterial incorporated into the host's tissue by ingrowth of young muscle fiber and massive new blood vessel formation in between the fibrous tissue.
Metallic materials implanted into bone defects are generally encapsulated by a fibrous tissue. Some metallic materials such as titanium and tantalum, however, have been revealed to bond to the living bone without forming the fibrous tissue, when they were subjected to NaOH solution and heat treatments. Thus treated metals form bone tissue around them even in muscle, when they take a porous form. This kind of osteoconductive and osteoinductive properties are attributed to sodium titanate or tantalate layer on their surfaces formed by the NaOH and heat treatments. These layers induce the deposition of bonelike apatite on the surface of the metals in the living body. This kind of bioactive metals are useful as bone substitutes even highly loaded portions, such as hip joint, spine and tooth root.
One of the emerging technologies in the area of plasma processing is plasma immersion ion implantation (PSII). The paper addresses the merits offered by the PSII technique especially in the area of biomaterial processing. Worldwide development status as well as the drive towards commercial applications is elaborated in an attempt to draw the attention to the importance of the process for Malaysia as well as south East Asia.
We report two cases of large chest wall primary chondrosarcoma, one of the sternum and the other of the lateral chest wall. Both were treated by radical resection and reconstruction using marlex mesh and methyl methacrylate "sandwich" prosthesis and pedicled latissiumus dorsi flap.
When referring to amputation, the immediate association tends to be amputation related to trauma. There is little doubt that injury is by far the commonest cause of amputation, but one must not forget that babies might also be born with amputations of the upper limb. This latter group of amelia composes the various types of congenital amputations.
A 68-year-old female presented with a 1-month history of lower back pain with right-sided radiculopathy and numbness. She was diagnosed with lumbar spondylosis and treated conservatively with analgesia and physiotherapy. Imaging showed multiple susuk, a metal alloy, in the lower back region and other regions of the body. The patient had undergone traditional medicine consultation 10 years earlier when the susuk was inserted in the lower back as talisman. The practice of the insertion of susuk is popular in rural East Malaysia and Indonesia. These foreign bodies act as possible causes of chronic inflammation and granuloma formation. In addition, the localised heighten peril upon imaging. This report suggests that the insertion of multiple susuk as talisman carries risk to safety of patients when imaging, and this practice complicates the management of musculoskeletal disorders.
Matched MeSH terms: Prostheses and Implants/adverse effects*