To use a 3D printed poly (L-lactide) acid (PLLA) and hydroxyapatite (HA) composite as a bone substitute for reconstruction of a critical bone defect in the radius of rabbits. Methods: A 1.5 cm ostectomy was performed in the radial diaphysis of 60 New Zealand white rabbits. The rabbits were divided into three groups according to surgical treatment of the bone defect (group I -control, group II -bone graft, group III -3D PLLA). Each group was divided into four subgroups with different radiographic and histopathologic evaluation times (T1 -15 days, T2 -30 days, T3 -60 days, T4 -90 days). Results: The implant group had greater clinically lameness (p = 0.02), edema (p = 0.007), pain (p = 0.04) and more complications at the surgical site (p = 0.03). Histologically, this group showed greater congestion (p = 0.04), hemorrhage (p = 0.04) and inflammation. Osteogenesis was microscopically similar between days (p = 0.54) and treatments (p = 0.17), even though radiographically, more effective bone healing occurred in the graft group (II), with more callus and bone bridge formation. Conclusions: The customization of a 3D PLLA/HA scaffold was successful. However, in animals receiving the polymer-ceramic composite less bone callus and bone bridge was formed compared to the graft group.
The objective of this research was to determine in necropsied dogs the best time for fixation in ethylic alcohol (EA) and preservation in 30% sodium chloride aqueous solution (SCAS 30%), aiming micro-surgical training. Five groups of necropsied dogs (G1 to G5) were fixed with EA, and put in boxes containing EA for 30 (G2), 60 (G3), 90 (G4) or 120 days (G5). After that, each group was preserved in SCAS 30% for 120 days. The control group (G1) was composed by cadavers without fixation/preservation. At the end of each period, two fragments of external jugular vein per cadaver were collected, for traction test. Immediately after the collection, the cadavers femoral veins were evaluated (by 2 people) regarding the suture quality in binocular surgical microscope, and attributed scores from 0 (bad) to 5 (excellent), regarding the fresh samples. The average at the maximum rupture strength of the G3 fixation end (21.51N), such as the average of the G2 preserving end (21.62N) remained closer to the control group (19.98N) and the G2 was the group with the best score for venous suture training. The EA was efficient as a fixative just like SCAS as a dog cadavers’ preservative. The small change of the traction test values, together with the best suture score, indicated the group kept for 30 days in EA and SCAS (G2) as the best for venous micro-surgical training.
Summary The use of biological membranes in surgeries is a reality for years, and one of the most used is the bovine pericardium, so the purpose of this research is to describe the bovine pericardium's biomechanics by comparing two directions of a test, one parallel to the longitudinal heart axis and one perpendicular. 20 adult bovine pericardium were tested for the maximum rupture force and rupture elongation, collecting four samples of each pericardium direction. In phase 2, eight pericardia were conserved for 4 months in a 98% glycerine solution, and the solution in which they were submerged was microbiologically analysed monthly. The Mann–Whitney test was used; there was a very significant difference between the perpendicular and parallel groups (p = .0001). The T test showed no significant difference for the rupture elongation (p = .0938). In pericardium preserved in glycerine, the outliers were removed regarding the maximum rupture force, and a Boxcox transformation was performed (λ = 0.25). Outliers were removed for the rupture elongation, and Bartlett's test (p = .7836), and Cramer–Von Mises (p = .5033) were performed and then, the analysis of variance (p < .0001), followed by the Tukey test at 5%. In the microbiological analysis, there was no presence of microorganisms during conservation. The research has shown that the pericardium collection direction influences its resistance and it can be stored in glycerine for 4 months without losing biomechanical characteristics.
There are several fixative or preservative solutions for use on cadavers, and formaldehyde is the most widely used. However, this chemical may present negative effects for professionals who manipulate it. Therefore, this study aimed to identify and quantify the main microorganisms related to the fixation and preservation of dog cadavers using an alternative and formaldehyde-free solution. After arterial injection (120 mL kg?1 95% 96° GL ethyl alcohol and 5% pure glycerin), cadavers were placed in 96° GL ethyl alcohol for 30 (group 1), 60 (group 2), 90 (group 3), and 120 days (group 4). After the fixation period, they remained under preservation in a 30% aqueous sodium chloride solution for 120 days. Bacterial quantification was performed by the pour plate method. The bacterial population was present in all groups during fixation, except for group 1, but never exceeded 9 × 101 CFU mL?1 in total aerobes and 7 × 101 CFU mL?1 in total anaerobes. The microbial population was present in all groups in at least two moments during preservation and never exceeded 7 × 101 CFU mL?1 in total aerobes and anaerobes. The presence of fungi was observed in 8 out of 34 analyses. Pseudomonas sp., Escherichia coli, and Bacillus sp. were identified in the analyzed samples. Microbiological counting was low, and no signs of contamination were observed in the vats at visual inspection.
Cervical arthroplasty with disc prosthesis has been proposed as a treatment option for dogs with Cervical Spondylomyelopathy. The present study developed a novel vertebral disc prosthesis for dogs. Sixteen Functional Spinal Units (C5-C6) were collected from dog cadavers with body weights ranging between 25 and 35 kg, and their vertebral measurements were used to design a prosthetic disc. The sizing of the prosthesis was performed based on the averages of the measurements of width, height, and length of the vertebral bodies from C5-C6 of all specimens. The prosthesis was developed using the Rhinoceros 3D® and SolidWorks® programs, and 3D prototyping was carried out to define the best design. The developed prosthesis consisted of two independent parts that are fixed to the cranial and caudal vertebral bodies, in the intervertebral space, and fitted together by metal-to-metal surfaces capable of moving in the lateral, ventral, and dorsal directions. Each part of the prosthesis is angled in two portions: vertically, in the intervertebral space, and horizontally, in contact with the ventral surface of the vertebral bodies, both of which are fixed by means of monocortical locking screws. The design of the developed prototype allowed a good fit in the intervertebral space between C4-C5, C5-C6, and C6-C7.
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