RESUMEN
Implantable orthopedic devices have had an enormously positive impact on human health; however, despite best practice, patients are prone to developing orthopedic device-related infections (ODRI) that have high treatment failure rates. One barrier to the development of improved treatment options is the lack of an animal model that may serve as a robust preclinical assessment of efficacy. We present a clinically relevant large animal model of chronic methicillin-resistant Staphylococcus aureus (MRSA) ODRI that persists despite current clinical practice in medical and surgical treatment at rates equivalent to clinical observations. Furthermore, we showed that an injectable, thermoresponsive, hyaluronic acid-based hydrogel loaded with gentamicin and vancomycin outperforms current clinical practice treatment in this model, eliminating bacteria from all animals. These results confirm that local antibiotic delivery with an injectable hydrogel can dramatically increase treatment success rates beyond current clinical practice, with efficacy proven in a robust animal model.
Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Animales , Antibacterianos/uso terapéutico , Gentamicinas , Humanos , Ácido Hialurónico , Hidrogeles , Ovinos , Infecciones Estafilocócicas/tratamiento farmacológico , VancomicinaRESUMEN
OBJECTIVE: To describe a technique and normal findings for arthroscopy of the stifle in rabbits. STUDY DESIGN: Cadaver study. ANIMALS: Twenty cadaveric stifles from New Zealand White rabbits were examined. METHODS: The arthroscope was placed through a medial portal, and instrument portals were created on the lateral aspect of the joint. The same portals were used for examination of the entire joint and palpation of structures with a probe. RESULTS: Structures identified in the proximal aspect of the stifle included the suprapatellar pouch, suprapatella, patella, medial and lateral proximal recesses, medial and lateral trochlear ridges, trochlear groove. Structures identified in the distal aspect of the joint included the cranial and caudal cruciate ligaments, medial and lateral menisci, medial and lateral femoral condyles, the long digital extensor tendon, and the cranial meniscal ligaments were identified. All of the proximal structures could be seen in 16/20 limbs. Distally, the cranial cruciate ligament could be identified and manipulated most often (17/20 limbs), followed by the caudal cruciate ligament (11/20), the menisci (9/20), and condyles (9/20). The average examination time was 27 minutes. There was a variably present femorotibial membrane. CONCLUSION: We conclude that the arthoscopic evaluation of the stifle in rabbits is a viable surgical approach and could be used for rabbit models or to examine clinical cases with stifle pathology. Precise portal placement and adequate infrapatellar fat pad debridement were critical for success.
Asunto(s)
Artroscopía/veterinaria , Conejos/cirugía , Rodilla de Cuadrúpedos/cirugía , Animales , Ligamento Cruzado Anterior/cirugía , Artroscopía/métodos , Cadáver , Meniscos Tibiales/cirugía , Conejos/anatomía & histología , Rodilla de Cuadrúpedos/anatomía & histologíaRESUMEN
OBJECTIVE: To evaluate clinical signs, diagnosis, treatment and outcome of cattle with sinonasal cysts. STUDY DESIGN: Case series. ANIMALS: Cattle (n = 15). METHODS: Medical records (2004-2011) of cattle with a fluid-filled mass in the nasal cavity, conchae, and/or paranasal sinuses were evaluated. Data retrieved and analyzed were reason of presentation, clinical signs, diagnostic techniques, surgical treatment, complications, and outcome. RESULTS: Common presenting clinical signs were abnormal respiratory noise, nasal discharge, and abnormal respiratory effort. Mean age of affected cattle was 21.7 months. In 9 animals, cysts were identified by endoscopy. Radiographic signs included a mass in the paranasal sinuses or conchae (13), nasal septum deviation (12), fluid lines (10), and bone atrophy (5). Ten cattle were treated surgically with osteoplastic flap techniques to gain access to the frontal or maxillary sinus (5), nasal extraction of the cyst under endoscopic control (3) or a combination of both techniques (2). Nine cattle returned to be productive members of their herd and had no recurrence (mean follow-up, 20.7 months). CONCLUSIONS: Sinonasal cysts should be considered as a primary differential diagnosis in cattle with abnormal respiratory noise, particularly in younger animals. Multiple cysts were common, which underlines the importance of a thorough preoperative examination using appropriate imaging modalities. Despite the often expansive nature of sinonasal cysts, the prognosis with surgical treatment was good.
Asunto(s)
Enfermedades de los Bovinos/cirugía , Quistes/veterinaria , Enfermedades Nasales/veterinaria , Animales , Bovinos , Quistes/cirugía , Procedimientos Quírurgicos Nasales/métodos , Procedimientos Quírurgicos Nasales/veterinaria , Enfermedades Nasales/cirugía , Estudios Retrospectivos , Colgajos Quirúrgicos , Resultado del TratamientoRESUMEN
BACKGROUND: Laterality defects are rare in cattle and usually manifest as asplenia or polysplenia syndrome. These syndromes may be associated with situs ambiguus, which is a dislocation of some but not all internal organs. The objective of this report was to describe the clinical and post-mortem findings including the macroscopic and microscopic anatomy of selected organs in a cow with polysplenia and situs ambiguus. CASE PRESENTATION: A 3.5-year-old Brown Swiss cow was referred to the Department of Farm Animals, Vetsuisse Faculty, University of Zurich, because of poor appetite and recurrent indigestion. A diagnosis of situs ambiguus was based on the results of physical examination, ultrasonography, exploratory laparotomy and post-mortem examination. The latter revealed that the rumen was on the right side and lacked compartmentalisation. There were two spleens, one on the left (26.5 x 12.0 cm) and one on the right (20.5 x 5.5 cm), and the omasum was located craniolateral to the ruminoreticulum on the left. The abomasum was located on the right, although it had initially been displaced to the left. The three-lobed liver occupied the left and central cranioventral aspect of the abdominal cavity (cavum abdominis). Only the right and left hepatic veins (vena hepatica dextra and sinistra) drained into the thoracic segment of the caudal vena cava (vena cava caudalis), and histological changes in the liver were indicative of impaired haemodynamics. The mesojejunum was not fused with the mesentery of the spiral loop (ansa spiralis) of the ascending colon (colon ascendens). The latter was folded and the transverse colon (colon transversum) ran caudal to the cranial mesenteric artery (arteria mesenteria cranialis). Fibrotic constrictions were seen in the lumen of the caecum and proximal loop (ansa proximalis) of the ascending colon. Both kidneys were positioned retroperitoneally in a lumbar position. The lumbar segment of the caudal vena cava did not descend to the liver and instead drained into the right azygous vein (vena azygos dextra). CONCLUSIONS: Recurrent digestive problems and poor production in this patient may have been caused by a lack of rumen compartmentalisation, abnormal abomasal motility, constrictions in the large intestine (intestinum crassum) and fibrosis of the liver. The abomasum had abnormal motility most likely because it was anchored inadequately and only at its cranial aspect to the liver by the lesser omentum (omentum minus) and to the dorsal abdominal wall and rumen by a short greater omentum (omentum majus).
Asunto(s)
Bovinos/anomalías , Síndrome de Heterotaxia/veterinaria , Animales , Bovinos/anatomía & histología , Femenino , Síndrome de Heterotaxia/patología , Hígado/anomalías , Omaso/anomalías , Rumen/anomalías , Bazo/anomalíasRESUMEN
Introduction: Emerging technologies such as three-dimensional (3D) cell culture and the generation of biological matrices offer exciting new possibilities in disease modelling and tumour therapy. The paucity of laboratory models for hepatoblastoma (HB), the most prevalent malignant liver tumour in children, has hampered the identification of new treatment options for HB patients. We aimed to establish a reliable 3D testing platform using liver-derived scaffolds and HB cell lines that reflect the heterogeneous biology of the disease so as to allow reproducible preclinical research and drug testing. Methods: In a sequence of physical, chemical and enzymatic decellularisation techniques mouse livers were stripped off all cellular components to obtain a 3D scaffold. HB cell lines were then seeded onto these scaffolds and cultivated for several weeks. Results: Our newly generated biological scaffolds consist of liver-specific extracellular matrix components including collagen IV and fibronectin. A cultivation of HB cell lines on these scaffolds led to the formation of 3D tumour structures by infiltration into the matrix. Analyses of drug response to standard-of-care medication for HB showed reliable reproducibility of our stocked models. Discussion: Our HB models are easy-to-handle, producible at large scale, and can be cryopreserved for ready-to-use on-demand application. Our newly generated 3D HB platform may therefore represent a faithful preclinical model for testing treatment response in precision cancer medicine.
RESUMEN
Benzoperylene derivatives with two angularly attached dicarboxylic imide rings, which were prepared by the Diels-Alder-reaction, exhibit strong fluorescence and their free peri positions allow either control of the UV/Vis spectra through their substituents or form anchor positions for the attachment of functional units. The angular chromophore 3 may be used both for fluorescent labeling such as for primary amines or enzymes or as building blocks for more complex assemblies where they may act as energy donors for FRET or electron acceptors in PET such as for photovoltaic solar cells.
RESUMEN
Local antibiotic therapy is increasingly being recognised for its role in preventing and treating orthopaedic device-related infection (ODRI). A bioresorbable, injectable gentamicin-loaded hydrogel has been developed to deliver local antibiotics at the time of surgery with potential for both prevention and treatment of ODRI. In a prophylaxis model, the antibiotic hydrogel was compared with systemic perioperative antibiotic prophylaxis alone in twelve sheep (six per group) at the time of intramedullary (IM) nail insertion to the tibia, which was inoculated with methicillin-sensitive Staphylococcus aureus (MSSA). In a treatment model of single-stage revision surgery, adjunctive antibiotic-loaded hydrogel was compared with systemic antibiotics alone in a single stage revision of MSSA infection associated with a tibia intramedullary nail in eleven sheep (five/six per group). The primary endpoint was quantitative microbiological results of soft tissue, bone and sonicate fluid from explanted hardware at the time of euthanasia. At euthanasia, the control sheep that received no local antibiotics in the prophylaxis model were all culture-positive (median 1x108, range 7x106-3x108 colony forming units, CFU) while only two of six sheep receiving local gentamicin had any culture positive biopsies (median 1x101, range 0 - 1x105 CFU). For the treatment model, sheep receiving only systemic antibiotics were all culture-positive (median 8x105, range 2x103- 9x106 CFU) while only two of six sheep treated with gentamicin-loaded hydrogel had any culture positive biopsies (median 3x102, range 0 - 7x104 CFU). Local gentamicin concentrations measured in extracellular fluid in the tibial canal show a burst release of gentamicin from the hydrogel. Serum gentamicin concentrations peaked in both models at one day post application and were below detection limit thereafter. This study has demonstrated the effective use of a locally delivered antibiotic hydrogel for both the prevention and treatment of ODRI that is superior to that of systemic antibiotics alone. Future studies will endeavour to translate from preclinical to clinical research trials.
Asunto(s)
Ortopedia , Infecciones Estafilocócicas , Animales , Antibacterianos/uso terapéutico , Modelos Animales de Enfermedad , Gentamicinas , Hidrogeles , Ovinos , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/prevención & controlRESUMEN
BACKGROUND: The aim of this case report was to describe the clinical findings, treatment and outcome of lumbosacral discospondylitis in a calf. CASE PRESENTATION: A 5.5-month-old calf was presented with difficulty in rising, a stiff and slightly ataxic gait in the hind limbs and a shortened stride. The lumbosacral region was severely painful on palpation.Radiographic examination confirmed lumbosacral discospondylitis. Medical treatment with stall rest was instituted over six weeks. Radiographic and ultrasonographic follow-up examinations showed lysis of the endplates initially, then collapse of the intervertebral space at the lumbosacral junction and progressive sclerosis in the periphery of the lytic zones. Four weeks after institution of treatment, the calf could rise normally and the general condition gradually had returned to normal. The calf was discharged after 6 weeks and was sound at 3.5 months clinical and radiographic follow up examination. Thereafter, it was kept on alpine pastures without problems and was pregnant 1 year after the last examination. CONCLUSIONS: This report shows that recovery from lumbosacral discospondylitis is possible in heifers, provided that treatment is started before major neurologic deficits have developed and is continued for an extended period of time.
Asunto(s)
Antiinfecciosos/uso terapéutico , Enfermedades de los Bovinos/diagnóstico , Cefalosporinas/uso terapéutico , Discitis/veterinaria , Animales , Bovinos , Enfermedades de los Bovinos/diagnóstico por imagen , Enfermedades de los Bovinos/tratamiento farmacológico , Discitis/diagnóstico , Discitis/diagnóstico por imagen , Discitis/tratamiento farmacológico , Femenino , Región Lumbosacra/diagnóstico por imagen , Radiografía , UltrasonografíaRESUMEN
BACKGROUND: The aim of this report was to describe duodenal obstruction caused by a rubber foreign body in a cow. CASE PRESENTATION: The clinical, biochemical and ultrasonographic findings in a five-year-old Swiss Braunvieh cow with duodenal ileus caused by a calf feeding nipple are described. The main clinical signs were anorexia, ruminal tympany, decreased faecal output and abomasal reflux syndrome. Ultrasonographic examination revealed reticular hyperactivity and a dilated duodenum. A diagnosis of duodenal ileus was made and the cow underwent right-flank laparotomy, which revealed a dilation of the cranial part of the duodenum because of obstruction by a pliable foreign body. This was identified via enterotomy as a calf feeding nipple. The cow was healthy at the time of discharge four days after surgery and went on to complete a successful lactation. CONCLUSIONS: To our knowledge, this is the first description of duodenal obstruction by a calf feeding nipple. This is an interesting case, which broadens the spectrum of the causes of duodenal ileus, which is usually caused by obstruction of the duodenum by a phytobezoar.
Asunto(s)
Enfermedades de los Bovinos/etiología , Enfermedades Duodenales/veterinaria , Cuerpos Extraños , Ileus/veterinaria , Animales , Bovinos , Enfermedades de los Bovinos/diagnóstico por imagen , Enfermedades de los Bovinos/cirugía , Enfermedades Duodenales/diagnóstico por imagen , Enfermedades Duodenales/etiología , Enfermedades Duodenales/cirugía , Femenino , Ileus/diagnóstico por imagen , Ileus/etiología , Ileus/cirugía , Laparotomía/veterinaria , UltrasonografíaRESUMEN
OBJECTIVE: To describe a technique used for reduction and internal fixation of sacral fractures in cattle. STUDY DESIGN: Case series. ANIMALS: Three heifers aged 19-32 months with deformation of the tail head and tail paralysis attributable to a closed fracture of S5 or S4 and S5. METHODS: Fractures were reduced and repaired under general anesthesia. A narrow, 6-10-hole, locking compression plate (LCP) was placed on the spinous processes of S5 and the first coccygeal (Co1) using 5.0 mm locking head screws. Follow-up inquiries were made by telephone (3/3), and cows were examined clinically and radiographically 2 (1 cow) to 9 (1 cow) months postoperatively. RESULTS: No complications were encountered. The range of movement of the tail improved so that soiling of the tail during defecation was no longer a problem. In all heifers, the normal top line was restored and there was no narrowing of the pelvic canal. Unassisted calving occurred in all heifers, and follow-up radiographs for 2 cows showed complete fracture healing. CONCLUSION: LCP-osteosynthesis of the spinous processes provided sufficient stability for internal fixation of sacral fractures. Marked improvement in tail function occurred postoperatively without decompression by laminectomy.
Asunto(s)
Placas Óseas/veterinaria , Enfermedades de los Bovinos/cirugía , Fijación Interna de Fracturas/instrumentación , Fracturas Óseas/veterinaria , Sacro/patología , Animales , Bovinos , Femenino , Fracturas Óseas/cirugía , Radiografía , Sacro/diagnóstico por imagenRESUMEN
CASE DESCRIPTION: 3 neonatal female calves (ages, < 1 to 4 days) were examined because of mandibular trauma. CLINICAL FINDINGS: Physical examination indicated that each calf had an open fracture of the mandibular pars incisiva (rostral mandibular fracture) with ventral displacement of the incisors at the affected region. Oral radiographs were obtained for 1 calf and revealed that 5 incisors were fractured at the level of the apical dental buds. TREATMENT AND OUTCOME: Each calf was anesthetized. The fracture site and surrounding tissues were surgically debrided and flushed with sterile 0.05% chlorhexidine solution. The laceration in the oral mucosa was closed with absorbable suture in an interrupted horizontal mattress pattern. Additionally, a Penrose drain was placed during primary closure and removed 4 days later in 1 calf. The fractured incisors were removed during primary debridement in another calf. All calves received perioperative antimicrobials and analgesics. One calf developed mild osteomyelitis of the rostral mandible, which resolved with additional surgical debridement and antimicrobial treatment. That calf and another developed mild brachygnathia. At the time of last follow-up (3 to 13 months after hospital discharge), all 3 calves were eating and growing as expected. CLINICAL RELEVANCE: 3 calves with open rostral mandibular fractures were successfully managed by surgical debridement and primary closure of the oral laceration. The procedure was easy to perform, did not require specialized equipment, and was less expensive than other repair methods. This procedure may be an effective and economic on-farm treatment alternative for calves with rostral mandibular fractures.
Asunto(s)
Enfermedades de los Bovinos , Fracturas Abiertas , Fracturas Mandibulares , Animales , Bovinos , Desbridamiento/veterinaria , Femenino , Fracturas Abiertas/veterinaria , Mandíbula , Fracturas Mandibulares/cirugía , Fracturas Mandibulares/veterinaria , Mucosa BucalRESUMEN
A 4.5-year-old Holstein-Friesian cow underwent surgery because of left abomasal displacement. Intra-operative palpation of the pyloric region revealed a phytobezoar. The abomasum containing the phytobezoar was exteriorized, and an incision was made directly over the mass in the region of the greater curvature of the pyloric part of the abomasum.
Asunto(s)
Abomaso/cirugía , Bezoares/veterinaria , Enfermedades de los Bovinos/cirugía , Laparotomía/veterinaria , Gastropatías/veterinaria , Animales , Bezoares/complicaciones , Bezoares/cirugía , Bovinos , Femenino , Gastropatías/cirugíaRESUMEN
OBJECTIVE: To explore if chemokine (C-C motif) ligand 5 (CCL5) delivery could recruit annulus fibrosus (AF) cells to the injury sites and facilitate the repair of ruptured AF. DESIGN: The effects of CCL5 on bovine AF cells in vitro were tested by transwell assay and quantitative real-time polymerase chain reaction. Fibrin gel containing CCL5 was used to treat annulotomized bovine caudal discs cultured under dynamic loading conditions. After 14 days of loading, the samples were collected for histological examination. A pilot animal study was performed using sheep cervical discs to investigate the effect of fibrin gel encapsulated with CCL5 for the treatment of ruptured AF. After 14 weeks, the animals were sacrificed, and the discs were scanned with magnetic resonance imaging before histopathological examination. RESULTS: CCL5 showed a chemotactic effect on AF cells in a dose-dependent manner. AF cells cultured with CCL5 in vitro did not show any change of the gene expression of CCL5 receptors, catabolic and proinflammatory markers. In vitro release study showed that CCL5 exhibited sustained release from the fibrin gel into the culture media; however, in the organ culture study CCL5 did not stimulate homing of AF cells toward the defect sites. The pilot animal study did not show any repair effect of CCL5. CONCLUSIONS: CCL5 has a chemotactic effect on AF cells in vitro, but no ex vivo or in vivo regenerative effect when delivered within fibrin gel. Further study with a stronger chemotactic agent and/or an alternate biomaterial that is more conductive of cell migration is warranted.
Asunto(s)
Materiales Biocompatibles/farmacología , Quimiocina CCL5/farmacología , Fibrina/administración & dosificación , Disco Intervertebral/efectos de los fármacos , Regeneración/efectos de los fármacos , Animales , Anillo Fibroso/efectos de los fármacos , Bovinos , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Modelos Animales de Enfermedad , Sistemas de Liberación de Medicamentos/métodos , Geles , Técnicas de Cultivo de Órganos , Proyectos Piloto , Receptores CCR5/efectos de los fármacos , OvinosRESUMEN
Tissue engineering repair of annulus fibrosus (AF) defects has the potential to prevent disability and pain from intervertebral disc (IVD) herniation and its progression to degeneration. Clinical translation of AF repair methods requires assessment in long-term large animal models. An ovine AF injury model was developed using cervical spinal levels and a biopsy-type AF defect to assess composite tissue engineering repair in 1-month and 12-month studies. The repair used a fibrin hydrogel crosslinked with genipin (FibGen) to seal defects, poly(trimethylene carbonate) (PTMC) scaffolds to replace lost AF tissue, and polyurethane membranes to prevent herniation. In the 1-month study, PTMC scaffolds sealed with FibGen herniated with polyurethane membranes. When applied alone, FibGen integrated with the surrounding AF tissue without herniation, showing promise for long-term studies. The 12-month long-term study used only FibGen which showed fibrous healing, biomaterial resorption and no obvious hydrogel-related complications. However, the 2 mm biopsy punch injury condition also exhibited fibrotic healing at 12 months. Both untreated and FibGen treated groups showed equivalency with no detectable differences in histological grades of proteoglycans, cellular morphology, IVD structure and blood vessel formation, biomechanical properties including torque range and axial range of motion, Pfirrmann grade, IVD height, and quantitative scores of vertebral body changes from clinical computed tomography. The biopsy-type injury caused endplate defects with a high prevalence of osteophytes in all groups and no nucleus herniation, indicating that the biopsy-type injury requires further refinement, such as reduction to a slit-type defect that could penetrate the full depth of the AF without damaging the endplate. Results demonstrate translational feasibility of FibGen for AF repair to seal AF defects, although future study with a more refined injury model is required to validate the efficacy of FibGen before translation.
RESUMEN
To evaluate the manner in which a cow's claws make contact with the ground at the walk, the gait, and in particular the claw-ground contact pattern, were studied in 12 healthy, lactating dairy cows, using high-speed cinematography (500frames/s) while the animals were walking on a treadmill. The results showed that the limbs were advanced around the contralateral limbs in a sigmoid curve. The feet contacted the ground with the foot axis and the tips of the claws rotated slightly outwards. In all cows the lateral claws contacted the ground before the medial claws in the hindlimbs, and in 10/12 cows in the forelimbs. The heel of the lateral claws was the region of initial contact with the ground in the hindlimbs of all cows and in the forelimbs in 9/12 cows. Lateral 'heel first' contact in the fore and hindlimbs appeared to be the normal gait pattern in these animals. Compared with a previous study of heifers, lactating cows had a larger step width in the hindlimbs and a smaller step width in the forelimbs. These ground contact patterns offer an explanation for the predisposition to claw disorders of the lateral claw of the hindlimb. The results of this study reinforce the suggestion that soft floor surfaces should be provided for cattle to prevent mechanical injury to the claws.
Asunto(s)
Marcha/fisiología , Pezuñas y Garras/fisiología , Lactancia/fisiología , Películas Cinematográficas , Caminata/fisiología , Animales , Huesos/fisiología , Bovinos , Femenino , Lateralidad FuncionalRESUMEN
OBJECTIVE: Sheep are used as a large animal model for intervertebral disc research. However, for the ovine ventral surgical approach to the cervical disc, limited descriptions exist. We, therefore, give a detailed in vivo anatomical description of this approach in sheep for the use in intervertebral disc regeneration and degeneration models to increase the reproducibility of such interventions. MATERIALS AND METHODS: Eighteen female Swiss white alpine sheep, with an age range of 2 to 4 years, were used. A ventral surgical access was performed to establish defined intervertebral disc punch defect from cervical levels C3/4 to C5/6. Cervical levels C2/3 and C6/7 were used as negative controls. Intraoperative findings, radiographical controls and postoperative clinical follow-up were documented and collected for this clinical report. RESULTS: All sheep recovered rapidly from the surgical intervention. Two sheep developed wound seroma, which resorbed spontaneously. Two further sheep showed wound dehiscence within 3 days after surgery, which had to be revised. No clinical wound infections occurred and all sheep healed well and did not show any side effects related to the surgical procedure. CONCLUSION: The ventral surgical access to the ovine cervical spine is a safe and reliable procedure. The advantage of the cervical intervertebral disc is the easier surgical access and the increased disc height compared to the sheep lumbar spine. Since the ovine cervical intervertebral disc shows a high grade of similarities (e.g. molecular characteristics) compared to human discs, it is a promising degeneration and regeneration model for disc diseases.
Asunto(s)
Vértebras Cervicales/cirugía , Degeneración del Disco Intervertebral/veterinaria , Procedimientos Ortopédicos/veterinaria , Ovinos/cirugía , Animales , Vértebras Cervicales/diagnóstico por imagen , Modelos Animales de Enfermedad , Femenino , Disco Intervertebral/cirugía , Degeneración del Disco Intervertebral/diagnóstico por imagen , Degeneración del Disco Intervertebral/cirugía , Complicaciones Posoperatorias/veterinaria , RadiografíaRESUMEN
Standardized and reproducible animal models are required for the assessment of bone healing mediated by biomaterials, cells, and drugs. Among the available bone-fractured models, calvarial defect is a simple and adequate option when researchers investigate intra-membranous bone formation and the influence of their regenerative solutions. However, the conventional surgical tools required to perform calvaria osteotomies (i.e., trephine bur mounted on a dental handpiece, DS) can affect the subjacent tissues of the skull, which are the dura mater and the brain. We hypothesized that the quality of the calvaria defect and the preservation of underlying tissues can be improved using a novel Anspach high-speed drill with a Codman Neuro Disposable Perforator handheld (ACP). Using a rabbit cadaveric models, we performed calvarial defects with either conventional DS or the ACP system, and showed that both techniques allowed to create standardized defects with circular geometry. We demonstrated that the ACP had clear benefices in terms of DM preservation and absence of exothermic reaction upon drilling. Even though this comparative work was conducted on cadaver, it is of substantial importance as it introduces a novel technique, easily applicable to investigate calvaria bone healing, which brings clear advantages compared to the conventional dental station. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-9, 2019.
Asunto(s)
Craneotomía/instrumentación , Animales , Femenino , Osteotomía/instrumentación , ConejosRESUMEN
INTRODUCTION: Implant-related infection is a challenging complication in musculoskeletal trauma surgery. In the present study, we examined the role of implant material and surface topography as influencing factors on the development of infection in an experimental model of plating osteosynthesis in the rabbit. METHODS: The implants included in this experimental study were composed of: standard Electropolished Stainless Steel (EPSS), standard titanium (Ti-S), roughened stainless steel (RSS) and surface polished titanium (Ti-P). Construct stability and load-to-failure of Ti-P implants was compared to that of Ti-S implants in a rabbit cadaveric model. In an in vivo study, a rabbit humeral fracture model was used. Each rabbit received one of three Staphylococcus aureus inocula, aimed at determining the infection rate at a low, medium and high dose of bacteria. Outcome measures were quantification of bacteria on the implant and in the surrounding tissues, and determination of the infectious dose 50 (ID50). RESULTS: No significant differences were observed between Ti-S and Ti-P regarding stiffness or failure load in the cadaver study. Of the 72 rabbits eventually included in the in vivo study, 50 developed an infection. The ID50 was found to be: EPSS 3.89×10(3) colony forming units (CFU); RSS 8.23×10(3) CFU; Ti-S 5.66×10(3) CFU; Ti-P 3.41×10(3) CFU. Significantly lower bacterial counts were found on the Ti-S implants samples compared with RSS implants (p<0.001) at the high inoculum. Similarly, lower bacterial counts were found in the bone samples of animals in the Ti-S group in comparison with both RSS and EPSS groups, again at the high inoculation dose (p<0.005). CONCLUSION: No significant differences were seen in susceptibility to infection when comparing titanium and steel implants with conventional or modified topographies. Ti-P implants, which have previously been shown in preclinical studies to reduce complications associated with tissue adherence, do not affect infection rate in this preclinical fracture model. Therefore, Ti-P implants are not expected to affect the infection rate, or influence implant stability in the clinical situation.
Asunto(s)
Placas Óseas , Fracturas del Húmero/cirugía , Infecciones Relacionadas con Prótesis/patología , Acero Inoxidable , Infecciones Estafilocócicas/patología , Titanio , Animales , Adhesión Bacteriana , Placas Óseas/microbiología , Cadáver , Modelos Animales de Enfermedad , Femenino , Fijación Interna de Fracturas , Fracturas del Húmero/microbiología , Fracturas del Húmero/patología , Ensayo de Materiales , Infecciones Relacionadas con Prótesis/microbiología , Conejos , Infecciones Estafilocócicas/microbiología , Propiedades de SuperficieRESUMEN
Implant-associated bone infections caused by antibiotic-resistant pathogens pose significant clinical challenges to treating physicians. Prophylactic strategies that act against resistant organisms, such as methicillin-resistant Staphylococcus aureus (MRSA), are urgently required. In the present study, we investigated the efficacy of a biodegradable Polymer-Lipid Encapsulation MatriX (PLEX) loaded with the antibiotic doxycycline as a local prophylactic strategy against implant-associated osteomyelitis. Activity was tested against both a doxycycline-susceptible (doxy(S)) methicillin-susceptible S. aureus (MSSA) as well as a doxycycline-resistant (doxy(R)) methicillin-resistant S. aureus (MRSA). In vitro elution studies revealed that 25% of the doxycycline was released from the PLEX-coated implants within the first day, followed by a 3% release per day up to day 28. The released doxycycline was highly effective against doxy(S) MSSA for at least 14days in vitro. A bolus injection of doxycycline mimicking a one day release from the PLEX-coating reduced, but did not eliminate, mouse subcutaneous implant-associated infection (doxy(S) MSSA). In a rabbit intramedullary nail-related infection model, all rabbits receiving a PLEX-doxycycline-coated nail were culture negative in the doxy(S) MSSA-group and the surrounding bone displayed a normal physiological appearance in both histological sections and radiographs. In the doxy(R) MRSA inoculated rabbits, a statistically significant reduction in the number of culture-positive samples was observed for the PLEX-doxycycline-coated group when compared to the animals that had received an uncoated nail, although the reduction in bacterial burden did not reach statistical significance. In conclusion, the PLEX-doxycycline coating on titanium alloy implants provided complete protection against implant-associated MSSA osteomyelitis, and resulted in a significant reduction in the number of culture positive samples when challenged with a doxycycline-resistant MRSA.
Asunto(s)
Antibacterianos/administración & dosificación , Doxiciclina/administración & dosificación , Staphylococcus aureus Resistente a Meticilina , Osteomielitis/prevención & control , Infecciones Estafilocócicas/prevención & control , Animales , Antibacterianos/química , Antibacterianos/uso terapéutico , Doxiciclina/química , Doxiciclina/uso terapéutico , Liberación de Fármacos , Farmacorresistencia Bacteriana , Femenino , Lípidos/química , Ratones Endogámicos C57BL , Polímeros/química , Prótesis e Implantes , Conejos , TitanioRESUMEN
The objective of this study was to establish a technique for radiographic examination of the coxofemoral joint and adjacent bony structures in standing cattle. Left (or right) 30° dorsal-right (or left) ventral radiographic views of the coxofemoral joint region of standing cattle (n = 10) with hind limb lameness were evaluated retrospectively. In addition, an experimental study of oblique laterolateral views of the coxofemoral joint region of a bovine skeleton at angles of 15-45° was carried out to determine the optimal position for visualization of the hip region. In the 10 clinical patients, the bodies of the ilium and ischium, the acetabulum and proximal third of the femur could be assessed. Six of these cattle had fractures of the body of the ilium and body of the ischium, five with and one without involvement of the acetabulum, two had craniodorsal and one caudoventral luxation of the femur and one had a femoral neck fracture. The described laterodorsal-lateroventral radiographs of the hip region in standing cattle were suitable for assessing the coxofemoral joint, the proximal aspect of the femur and parts of the ischium, ilium and pubis. After testing the optimal angle on the skeleton, it was seen that distortion and superimposition were minimized by positioning the X-ray beam at an angle of 25° to the horizontal plane. It can be concluded that the described technique improves the evaluation of injuries of the coxofemoral region in cattle. With the appropriate angle, the technique can also be applied in recumbent cattle.