Usability testing of a novel interlocking three-dimensional miniplate for mandibular angle fractures.

BACKGROUND: We developed a novel interlocking three-dimensional (3D) miniplate design with an adjustable configuration. As this device is new, surgeons must become familiar with its application. This study evaluated the usability and learning curves associated with the novel interlocking 3D miniplate for mandibular fracture fixation. METHODS: The study participants, nine plastic surgeons, were asked to apply an interlocking 3D miniplate and a standard miniplate to polyurethane mandible models. The participants had completed the Basic Craniomaxillofacial Osteosynthesis course during residency and had operated on craniomaxillofacial fractures within the past 5 years. They were instructed to place the interlocking 3D miniplate three times and the standard miniplate once. We assessed the time required for implant placement, the comfort level of the surgeons, and the biomechanical stability of the plates. Biomechanical testing was conducted by subjecting the mandible to forces ranging from 10 to 90 N and the displacement was measured. RESULTS: The results indicate increasing comfort with each attempt at placing the interlocking 3D miniplate, with a significant difference between the first and third attempts. Additionally, a reduction in application time was noted with repeated attempts, suggesting improved efficiency. Biomechanical tests showed comparable stability between the tested plates. CONCLUSION: Multiple attempts at applying the interlocking 3D miniplate resulted in increased comfort and reduced application time. These findings indicate that, despite its novelty, the interlocking 3D miniplate is relatively straightforward to apply and has a short learning curve. However, surgeons must have specific qualifications to ensure proper training and minimize errors during placement.

Novel Design of Interlocking 3-Dimensional Miniplate in Mandibular Angle Fractures: An In Vitro Study.

The evolution of osteosynthesis has led to the development of novel miniplate designs, including 3-dimensional (3D) miniplates, which offer improved biomechanical stability. However, mandible fractures resulting from the high impact have a complex fracture configuration. Hence, the authors developed interlocking 3D miniplate to overcome the difficulty in miniplate and screw placement to avoid critical anatomic structures, that is, dental roots and nerve, while still providing stability for the fracture fragments. The interlocking 3D miniplates can be formed according to the specific needs by adjusting the horizontal and vertical cross struts configuration. This study describes a design process of interlocking 3D miniplates and evaluates biomechanical performance compared to standard miniplates. Finite element analysis was performed to evaluate the design's stress state using human and goat mandible models under various loading conditions. After the authors, established that our design was feasible for fabrication, the authors developed the prototype for biomechanical testing. Biomechanical testing was conducted on 10 goat mandibles to compare stability and displacement under various load between the interlocking 3D miniplate and the standard miniplate configuration. Biomechanical testing revealed reduced displacement in all directions with the interlocking 3D miniplate compared to the standard miniplate. Furthermore, there was a significant difference in all loads in the buccal-lingual displacement ( P <0.05). The novel interlocking 3D miniplate design shows an adequate ability to provide stability for fixation for mandibular fractures, as evidenced by finite element analysis and biomechanical testing. Further research is necessary to validate these findings and explore the clinical application of interlocking 3D miniplates in mandibular fracture management.

Effects of bone types, particle sizes, and gamma irradiation doses in feline demineralized freeze-dried bone allograft.

BACKGROUND AND AIM: Fracture cases significantly increase recently, demanding high quality of bone graft materials. This research aimed to evaluate the effects of bone types, particle sizes, and gamma irradiation doses on morphological performance and cell viability of feline demineralized freeze-dried bone allograft (DFDBA) through an in vitro study. MATERIALS AND METHODS: Feline DFDBA derived from feline cortical and cancellous long bones was processed into four different sizes: Group A (larger than 1000 µm), B (841-1000 µm), C (420-840 µm), and D (250-419 µm) for each type of bones. The materials were then irradiated with two doses of gamma rays, 15 and 25 kGy, resulting in 16 variants of feline DFDBA. The surfaces of each material were then observed with the scanning electron microscope (SEM). The in vitro evaluation of feline DFDBA was then performed using 3-(4,5-dimethythiazol-2)-2,5-diphenyltetrazolium bromide (MTT) assay with calf pulmonary artery endothelial cells. RESULTS: The MTT assay results showed that the lowest inhibition rate (14.67±9.17 %) achieved by feline DFDBA in Group A derived from cortical bones irradiated with 15 kGy. Group D generally showed high inhibition rate in both cancellous and cortical bones, irradiated with either 15 or 25 kGy. The SEM results showed that cancellous and cortical bones have numerous macropores and micropores structure in 170× and 3000×, respectively. CONCLUSION: The material derived from cortical bones in Group A (larger than 1000 µm in particle size) irradiated with 15 kGy is the best candidate for further development due to its abundance of micropores structure and ability in preserving the living cells.

The Inflammatory and Foreign Body Reaction of Polymethyl Methacrylate Glaucoma Drainage Device in the Rabbit Eye.

Purpose: To assess the safety and tissue response of a polymethyl methacrylate (PMMA) glaucoma drainage device (GDD) in the rabbit eye. Methods: Specially constructed PMMA GDD devices were implanted into rabbit eyes and evaluated histopathologically following euthanasia on days 5, 30, and 60 after implantation surgery. Hematoxylin-eosin, Masson's trichrome, and periodic acid-Schiff were used to stain tissue specimens dissected from the surgical site. Inflammatory cell count and capsule thickness measurements were performed. Results: Three rabbits were sacrificed on day 5, 3 on day 30, and 4 on day 60. Macrophage and lymphocyte counts increased from day 5 to day 30 then decreased (P = 0.0000) with greater counts seen in the superior regions. At day 30, a fibrous capsule had formed around the plate area. Fibroblast counts increased significantly between day 5 to day 30 and again to day 60 (P = 0.001) with greatest numbers anteriorly. The inferior capsule thickness at day 60 was 243 µm (standard deviation, 120; 95% confidence interval: 53-433). The superior capsule thickness was 388 µm (standard deviation, 136; 95% confidence interval: 172-604). No adverse reactions were seen. Conclusions: Histopathologically, the inflammatory response toward this PMMA glaucoma drainage device was comparable to other reported GDDs. No accentuated response or adverse event was seen suggesting that PMMA may be useful as a GDD material. Translational Relevance: An affordable, locally built GDD is needed in Indonesia because of the high prevalence of severe glaucoma. This rabbit study is a significant step toward justifying the use of PMMA as a GDD material. PMMA is cheap and easily manufactured and sterilized in developing economies.

A Wearable Iron-Based Implant as an Intramedullary Nail in Tibial Shaft Fracture of Sheep.

A stable repaired fracture is the key factor responsible for the recovery of a damaged bone. The iron-based implant is one of the biodegradable metals that have been proven safe as a fracture fixation device. The objective of our experimental approach was to examine the potential of the iron-based implant as a biodegradable metal in tibia shaft fracture in sheep chronically. The samples used for this experiment were iron-based and stainless steel implants. Each had a diameter of 5 mm. These samples were analyzed through 3 phases which are material characterization, in vitro and in vivo examination. The samples were examined using a scanning electron microscope with energy dispersive spectrometer and X-ray diffraction. Based on the analysis carried out, the samples contained 90,02% and 60,81% Fe for iron-based implant and stainless implant, respectively. Both implants maintained high viability when being in contact with calf pulmonary artery endothelial cells, indicating that both implants had a minimum response to the cell in a hemocytometer and methyl tetrazolium (MTT) assay. The systemic effect of the implants was observed using hematology and blood chemistry examination. Data collection also shows that both implants also had a minimum response to the erythrocytes, leucocytes, blood chemistry, and blood mineral during the period of observation. Therefore, it could be concluded that the iron-based implant is tolerable for a period of 9 months. It also has the potential to be used as a biodegradable orthopedic implant.

Changes in histopathology and cytokeratin AE1/AE3 expression in skin graft with different time on Indonesian local cats.

AIM: A good skin graft histopathology is followed by formation of hair follicle, sweat gland, sebaceous gland, blood vessel, lightly dense connective tissue, epidermis, and dermis layer. This research aimed to observe histopathology feature and cytokeratin AE1/AE3 expression on cat skin post skin grafting within a different period of time. MATERIALS AND METHODS: Nine male Indonesian local cats aged 1-2 years old weighing 3-4 kg were separated into three groups. First surgery created defect wound of 2 cm × 2 cm in size to whole groups. The wounds were left alone for several days, differing in interval between each group, respectively: Group I (for 2 days), Group II (for 4 days), and Group III (for 6 days). The second surgery was done to each group which harvested skin of thoracic area and applied it on recipient wound bed. On day 24th post skin graft was an examination of histopathology and cytokeratin AE1/AE3 immunohistochemistry. RESULTS: Group I donor skin's epidermis layer had not formed completely whereas epidermis of donor skin of Groups II and III had completely formed. In all group hair follicle, sweat gland, sebaceous gland, and neovascularization were found. The density of connective tissue in Group I was very solid than other groups. Cytokeratin AE1/AE3 expression was found on donor skin's epithelial cell in epidermis and dermis layer with very brown intensity for Group II, brown intensity for Group II, and lightly brown for Group I. CONCLUSION: Histopathological structure and cytokeratin AE1/AE3 expression post skin graft are better in Groups II and III compared to Group I.

Subjective and objective observation of skin graft recovery on Indonesian local cat with different periods of transplantation time.

AIM: The success of a skin graft in a cat is highly dependent on the granulation formed by the base of recipient bed. Granulation by the base of recipient bed will form after several days after injury. This research aimed to observe subjective and objective profile of skin graft recovery on forelimb of cats with different periods of donor skin placement. MATERIALS AND METHODS: Nine male Indonesian local cats aged 1-2 years old, weighing 3-4 kg were divided into three groups. The first surgery for creating defect wound of 2 cm×2 cm in size was performed in the whole group. The wound was left for several days with the respective interval for each group, respectively: Group I (for 2 days), Group II (for 4 days), and Group III (for 6 days). In the whole group, the second surgery was done by the harvesting skin of thoracic area which then applied on recipient bed of respective groups. RESULT: The donor skin on Group II was accepted faster compared to Group I and Group III. The donor skin did not show color differences compared to surrounding skin, painless, bright red in bleeding test had faster both hair growth and drug absorption. Test toward the size of donor skin and the effect of drugs did not show a significant difference between each group. CONCLUSION: The observe subjective and objective profile of skin graft recovery on forelimb of cats on Group II were accepted faster compared to Group I and III.

EDTA-treated cotton-thread microfluidic device used for one-step whole blood plasma separation and assay.

This study aims to observe the wicking and separation characteristics of blood plasma in a cotton thread matrix functioning as a microfluidic thread-based analytical device (µTAD). We investigated several cotton thread treatment methods using ethylenediaminetetraacetic acid (EDTA) anticoagulant solution for wicking whole blood samples and separating its plasma. The blood of healthy Indonesian thin tailed sheep was used in this study to understand the properties of horizontal wicking and separation on the EDTA-treated µTAD. The wicking distance and blood cell separation from its plasma was observed for 120 s and documented using a digital phone camera. The results show that untreated cotton-threads stopped the blood wicking process on the µTAD. On the other hand, the deposition of EDTA anticoagulant followed by its drying on the thread at room temperature for 10 s provides the longest blood wicking with gradual blood plasma separation. Furthermore, the best results in terms of the longest wicking and the clearest on-thread separation boundary between blood cells and its plasma were obtained using the µTAD treated with EDTA deposition followed by 60 min drying at refrigerated temperature (2-8 °C). The separation length of blood plasma in the µTADs treated with dried-EDTA at both room and refrigerated temperatures was not statistically different (P > 0.05). This separation occurs through the synergy of three factors, cotton fiber, EDTA anticoagulant and blood platelets, which induce the formation of a fibrin-filter via a partial coagulation process in the EDTA-treated µTAD. An albumin assay was employed to demonstrate the efficiency of this plasma separation method during a one-step assay on the µTAD. Albumin in blood is an important biomarker for kidney and heart disease. The µTAD has a slightly better limit of detection (LOD) than conventional blood analysis, with an LOD of 114 mg L(-1) compared to 133 mg L(-1), respectively. However, the µTAD performed faster to get results after 3 min compared to 14 min for centrifuged analysis of sheep blood samples. In conclusion, on-thread dried-EDTA anticoagulant deposition was able to increase the wicking distance and has a better capability to separate blood plasma and is suitable for combining separation and the assay system in a single device.

The effect of hydrogen gas evolution of magnesium implant on the postimplantation mortality of rats.

BACKGROUND/OBJECTIVE: Hydrogen gas cavity is formed during in vivo degradation of magnesium implants. In many studies, the gas cavity is mostly punctured out subcutaneously. However, this procedure becomes inapplicable in certain internal surgeries; therefore, the effect of this gas cavity is worth further assessment. METHODS: In this study, we investigated the effect of hydrogen gas evolution on the mortality of rats and analysed the whole body capacity to relieve the gas. Porous pure-magnesium implants were implanted in the femoral bone defect of adult Sprague-Dawley rats up to 18 days, and their survival rate was calculated while the gas cavity size was measured, and its effect was analysed with support of radiographic and blood analysis. RESULTS: The gas cavity was rapidly formed surrounding the implantation site and obviously decreased the rats' survival rate. The gas was observed to swell the surrounding implantation site by filling the loose compartments and then dispersing subcutaneously to other areas. CONCLUSION: The rat's whole body capacity was unable to tolerate the rapid and persistent hydrogen gas cavity formation as shown by high postimplantation mortality.

Evidences of in vivo bioactivity of Fe-bioceramic composites for temporary bone implants.

Iron-bioceramic composites have been developed as biodegradable implant materials with tailored degradation behavior and bioactive features. In the current work, in vivo bioactivity of the composites was comprehensively studied by using sheep animal model. Five groups of specimens (Fe-HA, Fe-TCP, Fe-BCP composites, and pure-Fe and SS316L as controls) were surgically implanted into medio proximal region of the radial bones. Real-time ultrasound analysis showed a decreased echo pattern at the peri-implant biodegradation site of the composites indicating minimal tissue response during the wound healing process. Peripheral whole blood biomarkers monitoring showed a normal dynamic change of blood cellular responses and no stress effect was observed. Meanwhile, the released Fe ion concentration was increasing along the implantation period. Histological analysis showed that the composites corresponded with a lower inflammatory giant cell count than that of SS316L. Analysis of the retrieved implants showed a thicker degradation layer on the composites compared with pure-Fe. It can be concluded that the iron-bioceramic composites are bioactive and induce a preferable wound healing process.

Distribution, histochemical and enzyme histochemical characterization of mast cells in dogs.

This study describes the distribution, proteoglycan properties and protease activity of mast cells from 15 different dog organs. In beagles and mixed breed dogs, staining with Alcian Blue-Safranin O revealed mast cells in all the organs examined. However, their numbers varied and they demonstrated unique localization patterns within some of these organs. Berberine sulphate fluorescence-positive mast cells were observed in the submucosa, muscularis and serosa of the intestines, as well as the tongue and liver (within the connective tissue). Mast cells within the intestinal mucosa were negative for, or demonstrated weak, berberine sulphate staining. Heterogeneity of mast cells in terms of the proteoglycans contained within their granules was further confirmed by determination of critical electrolyte concentrations (CECs). The CECs of mast cells within the connective tissue of several organs, including the intestines (submucosal and muscularis-serosal layers) were all greater than 1.0 M. The results from CEC experiments together with berberine staining indicate that heparin was contained within their granules. Relative to the CECs of mast cells in other organs, mast cells in the intestinal mucosa exhibited lower CECs, suggesting that the proteoglycans within their granules were of lower charge density and/or molecular weight. Although mast cells were classified into two groups by proteoglycans within the granules, enzyme histochemical analysis in beagles revealed three subtypes of mast cells: chymase (MC(C)), tryptase (MC(T)) and dual positive (MC(TC)) cells. There was no correlation between the proteoglycan content and enzyme properties of the mast cell granules.

Enhanced protection against the migratory phase, but defective protection against the intestinal phase of Strongyloides venezuelensis infection in cotton rats, Sigmodon hispidus.

The protective capacity of the cotton rat, Sigmodon hispidus, against the migratory and intestinal phases of Strongyloides venezuelensis infection was examined. After subcutaneous infection with infective larvae (L(3)), adult worm recovery rates from male and female animals on Day 71 were only 0.10% and 0.06% of initial dose, respectively. To determine whether this enhanced protection was expressed during the migratory phase or the intestinal phase, larval recovery from the lungs of cotton rat was evaluated 3 days after subcutaneous L(3) infection. The larval recovery rate was only 0.5% of initial dose and about 40-fold lower than that from control mice. Protection in the intestine was also evaluated after intraduodenal implantation of adult worms. About 30% of implanted worms became established and worm burden remained constant until Day 28. Despite a high worm burden on Day 28, EPG was about 25-fold lower than the peak count. To evaluate expulsive capacity and monitor the cellular responses in the intestine of cotton rats, adult Nippostrongylus brasiliensis worms were implanted in addition to S. venezuelensis. Cotton rats were unable to expel adult S. venezuelensis worms, even after 21 days of observation. Although the number of mucosal mast cells increased significantly, the intraepithelial migration of mast cells was not observed. In contrast, N. brasiliensis was expelled by Day 6 in association with goblet cell hyperplasia. These results suggest that in cotton rats, the defective intestinal protection against adult S. venezuelensis worms results from dysfunction of mucosal mast cells.

Resistance of cotton rats, Sigmodon hispidus, to primary infection by Nippostrongylus brasiliensis.

The resistance of cotton rats, Sigmodon hispidus to Nippostrongylus brasiliensis infection was examined and compared the response to that of the susceptible Indian soft-furred rat, Millardia meltada. After a primary infection with infective third-stage N. brasiliensis larvae (L3), the number of eggs in feces and adult worm recovery rates from the small intestine of cotton rats were significantly lower than in the controls. To determine whether cotton rat resistance was observed during the migratory phase or the intestinal phase, cotton rats and control animals were challenged subcutaneously with L3 or intraduodenally with adult worms, and larval recovery from lungs and adult worm burden were evaluated. The recovery rate of larvae from the lungs of cotton rats was about five-fold lower than from controls. Adult worm recovery from the small intestine of cotton rats was also lower than that from the controls, but the difference (two-fold lower) was smaller than that observed for lung recovery. Carbon treatment at a dose of 250-500 mg/kg effectively increased larval worm recovery from the lungs of cotton rats. However, this treatment had no effect on worm recovery from the intestine after intraduodenal implantation of adult N. brasiliensis. These results suggest that macrophage function have important role in the expression of strong resistance during the migratory phase of N. brasiliensis infection in cotton rats.