Enhanced Bone Healing in Critical-Sized Rabbit Femoral Defects: Impact of Helical and Alternate Scaffold Architectures.

This study investigates the effect of scaffold architecture on bone regeneration, focusing on 3D-printed polylactic acid-bioceramic calcium phosphate (PLA-bioCaP) composite scaffolds in rabbit femoral condyle critical defects. We explored two distinct scaffold designs to assess their influence on bone healing and scaffold performance. Structures with alternate (0°/90°) and helical (0°/45°/90°/135°/180°) laydown patterns were manufactured with a 3D printer using a fused deposition modeling technique. The scaffolds were meticulously characterized for pore size, strut thickness, porosity, pore accessibility, and mechanical properties. The in vivo efficacy of these scaffolds was evaluated using a femoral condyle critical defect model in eight skeletally mature New Zealand White rabbits. Then, the results were analyzed micro-tomographically, histologically, and histomorphometrically. Our findings indicate that both scaffold architectures are biocompatible and support bone formation. The helical scaffolds, characterized by larger pore sizes and higher porosity, demonstrated significantly greater bone regeneration than the alternate structures. However, their lower mechanical strength presented limitations for use in load-bearing sites.

Use of 3D-printed polylactic acid/bioceramic composite scaffolds for bone tissue engineering in preclinical in vivo studies: A systematic review.

3D-printed composite scaffolds have emerged as an alternative to deal with existing limitations when facing bone reconstruction. The aim of the study was to systematically review the feasibility of using PLA/bioceramic composite scaffolds manufactured by 3D-printing technologies as bone grafting materials in preclinical in vivo studies. Electronic databases were searched using specific search terms, and thirteen manuscripts were selected after screening. The synthesis of the scaffolds was carried out using mainly extrusion-based techniques. Likewise, hydroxyapatite was the most used bioceramic for synthesizing composites with a PLA matrix. Among the selected studies, seven were conducted in rats and six in rabbits, but the high variability that exists regarding the experimental process made it difficult to compare them. Regarding the results, PLA/Bioceramic composite scaffolds have shown to be biocompatible and mechanically resistant. Preclinical studies elucidated the ability of the scaffolds to be used as bone grafts, allowing bone growing without adverse reactions. In conclusion, PLA/Bioceramics scaffolds have been demonstrated to be a promising alternative for treating bone defects. Nevertheless, more care should be taken when designing and performing in vivo trials, since the lack of standardization of the processes, which prevents the comparison of the results and reduces the quality of the information. STATEMENT OF SIGNIFICANCE: 3D-printed polylactic acid/bioceramic composite scaffolds have emerged as an alternative to deal with existing limitations when facing bone reconstruction. Since preclinical in vivo studies with animal models represent a mandatory step for clinical translation, the present manuscript analyzed and discussed not only those aspects related to the selection of the bioceramic material, the synthesis of the implants and their characterization. But provides a new approach to understand how the design and perform of clinical trials, as well as the selection of the analysis methods, may affect the obtained results, by covering authors' knowledgebase from veterinary medicine to biomaterial science. Thus, this study aims to systematically review the feasibility of using polylactic acid/bioceramic scaffolds as grafting materials in preclinical trials.

Modification of the Marmarou and Foda model of diffuse axonal injury (DAI) improves percentage survival of rats at 24 h and increases the amount of DAI identified.

More than two decades ago, Marmarou published a valid model for producing diffuse axonal injury (DAI) in rats. Since then, both mild and severe injuries have been obtained by researchers using the original method and a weight of 450 g. However, the diffuse brain injuries produced in rats were only similar to those seen in humans when the rats sustained severe brain injuries. In these cases, rat mortality in the original article was around 50%, and the cause of death was prolonged apnea post-impact. Rat survival after impact is critical for studying the progression of DAI. In order to explain the cause of death in human victims with cranial trauma who do not show gross brain injury, testing for the presence of DAI is essential. Thus, in order to minimize local and cervical injuries to increase rat survival, attention should be paid to the following aspects: a wider head protector disc should be used, the head of the rat should be elevated at the time of impact, and the foam bed should be soft enough to allow the movement caused by acceleration. With our modified method, rat survival increased by 30% compared to the original model (80% versus 50%). Moreover, 85.7% of rats demonstrated DAI after 24 h of survival. With these modifications, injuries appear in the same locations as in humans; thus, the method is suitable for the study of traumatic DAI in humans.

Design and biopharmaceutical preclinical characterisation of a new thermosensitive hydrogel for the removal of gastric polyps.

BACKGROUND AND AIMS: Submucosal injection agents are widely used solutions in gastric polyp resection techniques. Currently, many different solutions are used in clinical practice, but most are not authorised for this use or are not biopharmaceutical characterised. The objective of this multidisciplinary work is to test the efficacy of a novel thermosensitive hydrogel designed specifically for this indication. METHODS: A mixture design of various components (Pluronic®, hyaluronic acid and sodium alginate) was carried out to select the combination with optimal properties for this use. Three final thermosensitive hydrogels were selected on which biopharmaceutical characterisation was performed and stability and biocompatibility were analysed. Efficacy in maintaining elevation was tested ex vivo on pig mucosa and in vivo in pigs RESULTS: The mixture design allowed selection of the ideal combinations of agents for the characteristics sought. The thermosensitive hydrogels studied showed high values of hardness and viscosity at 37 °C, maintaining good syringeability. One of them demonstrated superiority in maintaining polyp elevation in the ex vivo assay and non-inferiority in the in vivo assay. CONCLUSION: The thermosensitive hydrogel specifically designed for this use is promising both for its biopharmaceutical characteristics and for its demonstrated efficacy. This study lays the foundation for evaluating the hydrogel in humans.

Laparoscopic versus Open Ovariectomy in Bitches: Changes in Cardiorespiratory Values, Blood Parameters, and Sevoflurane Requirements Associated with the Surgical Technique.

The aim of this study was to examine the cardiorespiratory and blood changes associated with pneumoperitoneum (PNP) in laparoscopic ovariectomy (LAP Ove), as well as sevoflurane requirements, comparing them to those determined in open surgery (LPT Ove). The study was performed in 16 bitches submitted to LAP or LPT Ove. The cardiorespiratory and end-tidal sevoflurane concentration values were recorded as follows: at the beginning of surgery (T1), after the right ovary resection (T2), after the left ovary resection (T3), and after surgical closure (T4). Blood samples were taken before and after PNP. Among the cardiorespiratory parameters, no differences were observed in the values of end-tidal CO2, minute volume, and heart rate. In the LAP Ove group, a significant increase in inspiratory pressures and a decreased compliance were identified at T2 and T3. Significant higher arterial pressure values were observed in both groups at T2 and T3, with this increase especially marked at T2 in the LPT Ove group. Sevoflurane requirements were significantly higher in the LPT group during ovarian resection. Finally, in terms of the hematochemical parameters, statistical differences were recorded between pre- and post-operative assessments, but not between both surgical groups. The pathophysiological effects associated with PNP seemed to be transient and well-tolerated by healthy dogs.

Incidence of Patellar Desmopathy in the Modified Maquet Technique with and without PRGF.

Patellar desmopathy can lead to desmitis, discomfort, and lameness. In the traditional MMT, a pin is used for the fixation of the fragment of the osteotomized tibia to the implant and the tibial diaphysis; this pin needs to be placed below the insertion of the patellar ligament to avoid damaging it. Considering the differences between TTA and MMT, the authors consider it important to determine the incidence of patellar desmopathy in the MMT. This is a prospective study that enrolled 53 owned dogs that underwent MMT and were followed up by a complete examination and radiograph controls to establish the patellar tendon thickening and the presence of clinical desmitis. The PRGF were administrated to 29 of those patients, in order to determine if PRGF's action could decrease ligament desmitis. The conclusions in this study were that the desmopathy produced by the MMT is similar to that generated by the TTA if the pin is carefully placed; in addition, the PRGF did not decrease the inflammation and the thickening of the ligament.

IMMOBILIZATION OF MOUFLON (OVIS ORIENTALIS MUSIMON) USING MEDETOMIDINE-KETAMINE-MORPHINE OR DEXMEDETOMIDINE-KETAMINE-MORPHINE.

This study is aimed at evaluating the efficacy of two protocols for the immobilization of mouflon (Ovis orientalis musimon). Six mouflon were immobilized twice using IM medetomidine 0.07 ± 0.01 mg/kg, ketamine 2.88 ± 0.48 mg/kg, and morphine 0.57 ± 0.09 mg/kg (MKM) or dexmedetomidine 0.04 ± 0.01 mg/kg, ketamine 3.01 ± 0.6 mg/kg, and morphine 0.60 ± 0.12 mg/kg (DKM). Anesthetic times were recorded from injection to initial drug effects, sternal recumbency, lateral recumbency, unresponsiveness to external stimuli, and recovery following atipamezole IM administration. Cardiopulmonary variables (HR in beats/min, RR in breaths/min, mean, systolic, and diastolic noninvasive blood pressure [MAP, SAP, DAP] in mm Hg, oxygen hemoglobin saturation [SpO2)], expired end tidal carbon dioxide [PECO2]), and rectal temperature in °C were monitored and recorded. No statistically significant differences were detected between protocols at any time point and no significant differences were detected in any measured variables at any time point between protocols. However, a significant decrease in the noninvasive blood pressure variables (SAP, MAP, and DAP) and in the RR were detected over time. Both chemical immobilization protocols provided at least 50 min of immobilization in mouflon, allowing minor procedures and tracheal intubation.

Does PRGF Work? A Prospective Clinical Study in Dogs with A Novel Polylactic Acid Scaffold Injected with PRGF Using the Modified Maquet Technique.

Tibial tuberosity advancement is a surgical technique to restore the dynamical stability in the knee by advancing the insertion of the patellar ligament, for which it is necessary to advance the tibial crest, being maintained in the desired position usually by a cage and metallic implants. The purpose of this study was to replace the cage with a polylactic acid biodegradable scaffold designed for each patient by 3D printing, inserting platelet-rich in growth factors (PRGF) to demonstrate its osteoinductive properties. To this end, we used the modified Maquet technique to reduce the amount of metal to a minimum. Fifty-three dogs finished the study. The control and PRGF groups did not present any statistically significant differences in terms of ossification degree (p > 0.001) but they demonstrated satisfactory ossification compared to previous publications, although in the PRGF group three of the scaffolds suffered complete reabsorption. The PRGF and control groups did not show any statistically significant differences in terms of lameness degree (p > 0.001). However, the PRGF group showed at the first control some analgesic and anti-inflammatory properties but they were not enough for reducing the functional recovery time in a significant way. The PRGF group did not show any complications or negative results associated with their use.

Crambescin C1 Acts as A Possible Substrate of iNOS and eNOS Increasing Nitric Oxide Production and Inducing In Vivo Hypotensive Effect.

Crambescins are guanidine alkaloids from the sponge Crambe crambe. Crambescin C1 (CC) induces metallothionein genes and nitric oxide (NO) is one of the triggers. We studied and compared the in vitro, in vivo, and in silico effects of some crambescine A and C analogs. HepG2 gene expression was analyzed using microarrays. Vasodilation was studied in rat aortic rings. In vivo hypotensive effect was directly measured in anesthetized rats. The targets of crambescines were studied in silico. CC and homo-crambescine C1 (HCC), but not crambescine A1 (CA), induced metallothioneins transcripts. CC increased NO production in HepG2 cells. In isolated rat aortic rings, CC and HCC induced an endothelium-dependent relaxation related to eNOS activation and an endothelium-independent relaxation related to iNOS activation, hence both compounds increase NO and reduce vascular tone. In silico analysis also points to eNOS and iNOS as targets of Crambescin C1 and source of NO increment. CC effect is mediated through crambescin binding to the active site of eNOS and iNOS. CC docking studies in iNOS and eNOS active site revealed hydrogen bonding of the hydroxylated chain with residues Glu377 and Glu361, involved in the substrate recognition, and explains its higher binding affinity than CA. The later interaction and the extra polar contacts with its pyrimidine moiety, absent in the endogenous substrate, explain its role as exogenous substrate of NOSs and NO production. Our results suggest that CC serve as a basis to develop new useful drugs when bioavailability of NO is perturbed.

Glucosamine and Chondroitin Sulfate: Is There Any Scientific Evidence for Their Effectiveness as Disease-Modifying Drugs in Knee Osteoarthritis Preclinical Studies?-A Systematic Review from 2000 to 2021.

Glucosamine and chondroitin sulfate have been proposed due to their physiological and functional benefits in the management of osteoarthritis in companion animals. However, the scientific evidence for their use is still controversial. The purpose of this review was to critically elucidate the efficacy of these nutraceutical therapies in delaying the progression of osteoarthritis, evaluating their impact on the synovial knee joint tissues and biochemical markers in preclinical studies by systematically reviewing the last two decades of peer-reviewed publications on experimental osteoarthritis. Three databases (PubMed, Scopus and, Web of Science) were screened for eligible studies. Twenty-two articles were included in the review. Preclinical studies showed a great heterogeneity among the experimental designs and their outcomes. Generally, the evaluated nutraceuticals, alone or in combination, did not seem to prevent the subchondral bone changes, the synovial inflammation or the osteophyte formation. However, further experimental studies may be needed to evaluate their effect at those levels. Regarding the cartilage status and biomarkers, positive responses were identified in approximately half of the evaluated articles. Furthermore, beneficial effects were associated with the pre-emptive administrations, higher doses and, multimodality approaches with some combined therapies. However, additional studies in the long term and with good quality and systematic design are required.

Histomorphometric Quantitative Evaluation of Long-Term Risedronate Use in a Knee Osteoarthritis Rabbit Model.

Osteoarthritis (OA) treatment is a major orthopedic challenge given that there is no ideal drug capable to reverse or stop the progression of the OA. In that regard, bisphosphonates have been proposed as potential disease-modifying drugs due to their possible chondroprotective effect related to obtaining a greater subchondral bone quality. However, their effectiveness in OA is still controversial and additionally, there is little evidence focused on their long-term effect in preclinical studies. The aim of this study was to evaluate the risedronate quantitative effect on articular and subchondral periarticular bone by histomorphometry, in an experimental rabbit model in an advanced stage of OA. Twenty-four adult New Zealand rabbits were included in the study. OA was surgically induced in one randomly chosen knee, using the contralateral as healthy control. Animals were divided into three groups (n = 8): placebo control group, sham surgery group and risedronate-treated group. After 24 weeks of treatment, cartilage and subchondral femorotibial pathology was evaluated by micro-computed tomography (micro-CT) and undecalcified histology. The research results demonstrated that the experimental animal model induced osteoarthritic changes in the operated joints, showing an increased cartilage thickness and fibrillation associated with underlying subchondral bone thinning and decreased trabecular bone quality. These changes were especially highlighted in the medial tibial compartments as a possible response to surgical instability. Regarding the trabecular analysis, significant correlations were found between 2D histomorphometry and 3D imaging micro-CT for the trabecular bone volume, trabecular separation, and the trabecular number. However, these associations were not strongly correlated, obtaining more precise measurements in the micro-CT analysis. Concerning the long-term risedronate treatment, it did not seem to have the capacity to reduce the osteoarthritic hypertrophic cartilage response and failed to diminish the superficial cartilage damage or prevent the trabecular bone loss. This study provides novel information about the quantitative effect of long-term risedronate use on synovial joint tissues.

Systematic Review and Quality Evaluation Using ARRIVE 2.0 Guidelines on Animal Models Used for Periosteal Distraction Osteogenesis.

The objective of this systematic review was to synthesize all the preclinical studies carried out in periosteal distraction osteogenesis (PDO) in order to evaluate the quality using the ARRIVE guidelines. The animal models used, and the influence of the complications, were analysed in order to establish the most appropriate models for this technique. The PRISMA statements have been followed. Bibliographic sources have been consulted manually by two reviewers. Risk of bias was evaluated using the SYRCLE tool for animal studies, and the quality of the studies with the ARRIVE 2.0 guidelines. The selection criteria established by expert researchers were applied to decide which studies should be included in the review, that resulted in twenty-four studies. Only one achieved the maximum score according to the ARRIVE 2.0 guidelines. The rabbit as an animal model has presented good results in PDO, both for calvaria and jaw. Rats have shown good results for PDO in calvaria. The minipig should not be recommended as an animal model in PDO. Despite the increase in the quality of the studies since the implementation of the ARRIVE 2.0 guidelines, it would be necessary to improve the quality of the studies to facilitate the transparency, comparison, and reproducibility of future works.

Preliminary Clinical and Radiographic Evaluation of a Novel Resorbable Implant of Polylactic Acid (PLA) for Tibial Tuberosity Advancement (TTA) by Modified Maquet Technique (MMT).

Our objectives were to determine whether PLA implants can be used in TTA with successful results; secondly, to observe whether they provide a faster bone healing; finally, to determine whether weight or age influences bone healing scores. PLA cages were created with a 3D printer. TTA by MMT with PLA implants was performed in 24 patients. Follow-ups were carried out pre-surgical, at 1, 2, and 5 months and consisted of a radiographic study and a lameness assessment. A comparison was performed in terms of weight and age. Patients data, time between follow-up examinations, healing score, and lameness score were compared between patients using commercial software for statistically significant differences p < 0.05. Eighteen dogs finished the study. The ossification degrees presented statistically significant differences between each other. PLA implants maintained the advancement in 100% of cases. Comparing weight and age did not present any statistically significant differences between groups. Lameness presented statistically significant differences between follow-up examinations. Complications were observed in 20.8%. PLA implants for TTA provide good functional results, presenting an acceptable rate of complications. They provide a faster bone healing of the osteotomy gap, which was not affected by age or body weight, and have a clinical recovery time similar to metallic implants.

Case Report: First Evidence of a Benign Bone Cyst in an Adult Teckel Dog Treated With Shark Teeth-Derived Bioapatites.

Bone cysts are a very rare orthopedic pathology in veterinary medicine, the general prevalence of which is unknown. A unicameral bone cyst was diagnosed in an adult female Teckel dog with a limp that was treated surgically by filling the defect with marine bioapatites. The treatment was effective and at 8 weeks the defect had remodeled 50.24%. Eighteen months after surgery, the defect had remodeled 94.23%. The limp disappeared after surgery, and functional recovery was good in all stages after surgery. No adverse reactions were observed at the local or systemic level. This is the first report of a benign bone cyst in an lame adult female Teckel successfully treated with a novel marine bioapatite.

Bisphosphonates as disease-modifying drugs in osteoarthritis preclinical studies: a systematic review from 2000 to 2020.

Bisphosphonates have been proposed as possible disease-modifying drugs in osteoarthritis. However, the evidence of their efficacy is poor and their outcomes presented a great heterogeneity. Therefore, the aim of this study is to systematically review the main effects of bisphosphonate use on synovial joint tissues and biochemical markers in preclinical studies over the past two decades (2000-2020). Three databases (Pubmed, Scopus, and Web of Science) were searched, and after screening, twenty-six studies with five different types of bisphosphonates were included in the review. The animal model selected, the type of bisphosphonate used, the therapy duration, and the main effects of individual drugs on synovial tissues were evaluated. Additionally, the quality and risk of bias assessments were performed using the Animals in Research Reporting In Vivo Experiments guidelines and the Systematic Review Centre for Laboratory animal Experimentation tool. Studies showed high variability in experimental designs. Consequently, the comparison of the findings in order to draw specific conclusions about the effectiveness of the drugs is complicated. However, the results of this systematic review suggested that bisphosphonates seemed to reduce the osteoarthritic changes in a dose-dependent manner showing better chondroprotective effects at high doses. Besides, a time-dependent efficacy was also detected in terms of cartilage status. One can conclude that the disease stage of the time-point of treatment initiation may constitute a key factor in the antiresorptive drug efficacy. Generally, we noted that bisphosphonate administration seemed to show positive subchondral bone conservation and fewer biomarker alterations. However, they did not appear to suppress the osteophyte development and their chondroprotective effect is highly variable among the studies. Bisphosphonates appeared to show a positive anti-inflammatory effect on the synovial membrane. However, only a few included publications were focused on their investigation. Regarding the therapy duration, there is a significant lack of evidence on evaluating their effectiveness in preclinical long-term studies and further experimental studies may be needed to examine the pharmacological response in these circumstances. This systematic review might help to clarify the efficacy of bisphosphonates and their function as disease-modifying treatments in osteoarthritis.

Does the Animal Model Influence in Vertical Alveolar Distraction? A Systematic Review of the Literature.

This study is aimed at synthesizing all available evidence on vertical alveolar osteogenesis distraction (VAOD) in animal trials to determine whether the animal model used and its handling influence or not, and find which is the most appropriate animal model for this specific technique. This systematic review has been carried out following the PRISMA statements. Bibliographic sources have been consulted manually by two reviewers. Risk of bias was assessed using a version of the Newcastle-Ottawa-Scale (NOS). The selection criteria established by expert researchers were applied in order to decide which studies should be included in the review. Twenty-six studies met the inclusion criteria and were included in the review. Twenty-four of them had a high quality (score between 7 and 9), two medium quality (score between 4 and 6), and none low quality (score between 1 and 3). The highest possible score was 9 (using the NOS). Six studies complied with all NOS criteria. The animal model has been seen to influence the results, leading to failure in some cases. The most used animal model on VAOD, with fewer complications, was the Mongrel dog. The use of the pig and minipig is not recommended, due to the difficulties in handling and complications encountered.

No Effect of Long-Term Risedronate Use on Cartilage and Subchondral Bone in an Experimental Rabbit Model of Osteoarthritis.

Osteoarthritis (OA) is the most prevalent degenerative joint disease in animals and humans. It is characterized by pain, articular cartilage damage and joint stiffness. It has been suggested that the status of the subchondral bone compartment plays an important role in the initiation and progression of OA. Bisphosphonates have been proposed as a potential disease-modifying treatment for OA, however their effectiveness is not yet clear. Twenty-four male adult New Zealand rabbits were used to evaluate the effects of risedronate on the subchondral bone quality and cartilage degradation in a long-term model of experimentally induced OA. Animals underwent an anterior cruciate ligament transection and partial medial meniscectomy or sham operation in only one knee, which was randomly chosen, using the contralateral as healthy control. Animals were divided into three groups (n = 8): untreated control group and sham surgery control group; both groups received only vehicle; and risedronate group, treated with 2.5 mg orally weekly for 24 weeks. Stifle joints were harvested and scanned using a high-resolution micro-CT to evaluate the subchondral plate and trabecular bone changes. The macroscopic evaluation and histological analysis were determined using an adapted Osteoarthritis Research Society International scoring scheme to assess the cartilage degeneration. The lateral and medial femoral condyle and tibial plateau were evaluated. Additionally, the histological synovial membrane assessment was carried out. Sample analysis showed that the experimental model induced osteoarthritic changes in the operated joints, whereas in sham-operated rabbits, almost no histological changes were observed on articular cartilage surfaces. In terms of macroscopic and histological analyses, risedronate-treated animals did not show improved cartilage health compared with untreated operated rabbits, but a slightly anti-inflammatory activity was observed in the synovial membrane. Risedronate administration showed a slight tendency to increase subchondral bone plate thickness in lateral compartments but, it did not show conservation of periarticular bone and was not be able to suppress the osteophyte formation. In conclusion, long-term risedronate use did not demonstrate a positive effect on reducing the cartilage damage, and failed to prevent the subchondral bone changes and osteophytogenesis in an experimental rabbit model of OA.

Application of Shark Teeth-Derived Bioapatites as a Bone Substitute in Veterinary Orthopedics. Preliminary Clinical Trial in Dogs and Cats.

Background: The autograft is still considered the gold standard for the treatment of bone defects. However, given the significant morbidity of the donor site with which it has been associated, alternative substitutes for bone grafts have been developed. In the present study, a bone substitute composed of CaP biphasic bioceramics obtained from shark teeth was used (BIOFAST-VET). Objective: The objective of this study is to evaluate the efficacy of a marine bioapatite in the veterinary clinical field using it as a bone-grafting scaffold in dogs and cats. Methods: The biomaterial was randomly distributed in 6 veterinary clinical centers in Spain and was used in 24 cases (20 dogs and 4 cats) including 14 fractures, 9 arthrodesis, and 1 bone cyst. Grains between 500 and 2,000 µm were used. Inclusion and exclusion criteria were established. The time of consolidation and functional recovery were quantitatively and qualitatively assessed. For this, a follow-up was carried out at 2, 4, 8, and 12 weeks, included radiographic images, physical examination and sharing the feedback with the owners. Results: Nineteen cases completed the study (18 dogs and 1 cat; 11 fractures, 7 arthrodesis, and 1 bone cyst). The remaining five were excluded because they did not complete the radiographic follow-up (three cats and two dogs), being three arthrodesis and two fractures. In 18 of 19 cases, the use of the biomaterial was successful; the remaining one failed due to causes not related to the biomaterial. There were no systemic or local adverse reactions. Eighteen patients had a good functional recovery. The average consolidation time was 5.94 weeks in dogs with fractures and arthrodesis, not finding statistically significant differences between sex, weight, and procedure. Conclusions: This biomaterial is presented as a very suitable candidate for orthopedic surgery in the veterinary field. Preliminary results showed that its use reduces consolidation time in dogs with fractures and arthrodesis. In addition, no adverse systemic or local reactions have been observed derived from its use.

Effects of fentanyl on intraocular pressure and pupil size in medetomidine-methadone premedicated dogs: a pilot study.

BACKGROUND: This is a pilot study to evaluate the effects of fentanyl on intraocular pressure (IOP) and pupil size (PS) in dogs premedicated with medetomidine and methadone. METHODS: Sixteen dogs with a median (first quartile-third quartile) age of 3.5 (1.25-6) years and a mean (sd) weight of 18.6 (9.2) kg were included. Baseline readings of IOP and PS were recorded before all dogs were premedicated intramuscularly with medetomidine (10 µg/kg) and methadone (0.5 mg/kg). Both measurements were repeated 15 and 30 minutes later. Following this, the dogs were randomly assigned into two groups. The fentanyl group received intravenous fentanyl (10 µg/kg), while the control group received the same volume of saline solution intravenously. IOP and PS measurements were measured and recorded in both groups at one, five and ten minutes after intravenous injection. Data were analysed with one-way and two-way repeated-measures analysis of variance or their non-parametric equivalents. RESULTS: PS was significantly decreased 15 and 30 minutes following intramuscular premedication and IOP was significantly increased in the fentanyl group at all time points following intravenous administration. CONCLUSIONS: Medetomidine, methadone and fentanyl combinations are not recommended for use in patients where an increase in IOP or decrease in PS is undesirable.