Cadáveres de caninos conservados con alcohol etílico y sal de cura y embalados al vacío para la enseñanza de la cirugía veterinaria

The aim of this study was to biomechanically analyze the skin of canine corpses chemically prepared with ethyl alcohol and curing salt, and vacuum packed, for the practice of veterinary surgery, in addition to obtaining the microbiological evaluation that may occur during the process. Eight canine corpses, weighing 7.96 ± 1.48 kg, were used. The animals were injected with 120 ml/kg of a solution of 20% sodium chloride, 1% nitrite and 1% sodium nitrate, and 150 ml/kg of alcohol with 5% glycerin and kept in vacuum-plastic bags at temperature between 0 and 4 °C. Skin samples were taken on day 0 (fresh samples) and on days 30, 60, 90 and 120 for biomechanical analysis, as well as for microbiological analysis of the fluids in the plastic packaging containers. The maximum rupture force presented by the control group and in the days of conservation showed that the fixation with curimg salts and the storage in vacuum packs maintained the biomechanical characteristics of the skin for up to 120 days in the corpses under refrigeration.El objetivo de este trabajo fue analizar biomecánicamente la piel de cadáveres de caninos preparados químicamente con alcohol etílico y sal de cura, y embalados al vacío, para la práctica da cirugía veterinaria, además de obtener la evaluación microbiológica que se puede presentar durante el proceso. Se trabajó con ocho cadáveres de caninos, de peso 7.96±1.48 kg. Los animales fueron inyectados con 120 ml/kg de una solución de cloruro de sodio al 20%, nitrito al 1% y nitrato de sodio al 1%, y 150 ml/kg de alcohol con glicerina al 5% y se mantuvieron en envases al vacío a tempretatura entre 0 y 4 °C. Se tomaron muestras de piel el día 0 (muestras frescas) y los días 30, 60, 90 y 120 para análisis biomecánico, así como para análisis microbiológico de los fluidos en los envases del embalaje plástico. La fuerza máxima de ruptura presentada por el grupo control y en los días de conservación demonstró que la fijación con las sales de cura y el almacenamiento en embalajes al vacío mantuvo las características biomecánicas de la piel hasta por 120 días en los cadáveres bajo refrigeración

Cadáveres de gatos preparados químicamente para la enseñanza de técnicas quirúrgicas

The aim of this study was to evaluate the feasibility of using ethanol (AE) and an aqueous sodium chloride solution 30% (ASCS) in various time periods for the preparation of carcasses of cats for the teaching of surgical techniques. The corpses of 60 cats were used. The specimens were fixed in AE, according to group, for 30 days (G1), 30 and 60 days (G2) and 30, 60 and 90 days (G3), and ASCS was applied to all of them at 30, 60, 90 and 120 days of conservation and the result was measured by means of the biomechanical study in the tissues to determine the best moment to interrupt the fixation in AE using as control the greatest similarity in tissue resistance found in fresh cadavers. The use of the anatomical technique using AE and ASCS was efficient throughout the experiment. There was no significant difference between the mean value of the maximum breaking force (N) or between the storage groups in the ASCS and the control group in any of the groups for the skin samples. Neither was there a significant difference in maximum force between fixation and preservation groups, compared to the control group in the groups for jejunum samples. However, G2 presented less variation in the breaking force (-0.21 mm), being, therefore, the group most similar to fresh animals. The anatomical technique used was found to be efficient for both fixation and preservation of cat carcasses for up to seven months.El objetivo del estudio fue evaluar la factibilidad de utilizar alcohol etílico (AE) y una solución acuosa de cloruro de sodio al 30% (SACS) en varios periodos de tiempo para la preparación de cadáveres de gatos para la enseñanza de técnicas quirúrgicas. Se utilizaron los cadáveres de 60 gatos. Los especímenes fueron fijados en AE, según grupo, por 30 días (G1), 30 y 60 días (G2) y 30, 60 y 90 días (G3), y a todos se les aplicó SACS a los 30, 60, 90 y 120 días de conservación y el resultado fue medido mediante el estudio biomecánico en los tejidos para determinar el mejor momento para interrumpir la fijación en AE, utilizando como control la mayor similitud en la resistencia tisular encontrada en cadáveres frescos. El uso de la técnica anatómica utilizando AE y SACS fue eficiente durante todo el experimento. No hubo diferencia significativa entre las medias de la fuerza máxima de ruptura (N) ni entre los grupos de almacenamiento en el SACS y el tiempo de control en ninguno de los grupos para las muestras de piel. Tampoco se observó diferencia significativa en la fuerza máxima entre los grupos de fijación y preservación, comparado al grupo control en los grupos para las muestras de yeyuno. No obstante, G2 presentó menor variación en la fuerza de ruptura (-0.21 mm), siendo, por lo tanto, el grupo más parecido a los animales frescos. Se encontró que la técnica anatómica utilizada es eficiente tanto para la fijación y para la conservación de cadáveres de gatos por hasta siete meses

Biomechanical evaluation of four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs

ABSTRACT Purpose: This study compared, through biomechanical evaluation under ventral flexion load, four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs. Methods: In total, 28 identical atlantoaxial joint models were created by digital printing from computed tomography images of a dog, and the specimens were divided into four groups of seven. In each group, a different technique for ventral stabilization of the atlantoaxial joint was performed: transarticular lag screws, polyaxial screws, multiple screws and bone cement (polymethylmethacrylate–PMMA), and atlantoaxial plate. After the stabilization technique, biomechanical evaluation was performed under ventral flexion load, both with a predefined constant load and with a gradually increasing load until stabilization failure. Results: All specimens, regardless of stabilization technique, were able to support the predefined load without failing. However, the PMMA method provided significant more rigidity (p ≤ 0.05) and also best resisted the gradual increase in load, supporting a significantly higher maximum force (p ≤ 0.05). There was no statistical difference in flexural strength between the transarticular lag screws and plate groups. The polyaxial screws method was significantly less resistant to loading (p ≤ 0.05) than the other groups. Conclusions: The PMMA technique had biomechanical advantages in ventral atlantoaxial stabilization over the other evaluated methods

Development of an intervertebral disc prosthesis prototype for the canine cervical spine

ABSTRACT: 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

Interlocking Nail Combined with Locking Plate Fixation for a Distal Diaphysis Femur Comminuted Fracture in a Dog

Background: Interlocking Nail (ILN) is similar a solid intramedullary pins with screws or bolts passing through one and nail holes (locking effect). This implant mostly have been putted normograde, passing by trochanteric fossa of femur, although it is reported to be inserted through the knee, passing by fracture focus and ending close to proximal femur. It is carriedout especially when there is a comminuted fracture in distal third shaft of femur. Locking plate systems work as internal fixators with some advantages compared to conventional plates. It can be used combined with intramedullary pin, and is an effective technique for increase stifeness stabilization of comminuted long-bone fractures, especially for bending. Some studies reported the use of plate-nail to increase even more the stiffness of implants, because of locking screw in plate and nail. Based on the same propose, we aim to report a case of an ILNs normograde (from distal to proximal) connected to a locking plate in highly comminuted distal diaphyseal fracture since it is rarely report in veterinary medicine orthopaedics.Case: A 5-year-old male mixed breed dog was assessed and diagnosed a fracture of the femur in the right pelvic limb. On physical examination, the dog had nonweight bearing lameness in the affected limb and, mobility of the fragments was noted following digital pressure. A comminuted fracture of the distal diaphysis of the femur was identified. A lateral approach tothe shaft of the femur, the incision was extended to the stifle joint through a lateral incision because the fracture seemed to extend throughout the physis. Open but do not touch approach was performed and reduction was gotten without modified environment of fracture hematoma. A surgical drill was inserted through the access in distal extremity of the bone to openthe medullary cavity of the femur. After that, an interlocking nail was inserted into the opening into the distal fragment, the fracture was reduced and the nail was inserted towards the proximal end of the bone. At the next stage the nail was fitted into the medullary canal and it was locked relative to the main fragments of the femur using locking head screws that were anchored in the load carrier of the plate. Postoperative radiographic views documented appropriate implants location and satisfactory femur fracture alignment. At 3 weeks, the patient showed functional use of the limb with partial weight bearing.Discussion: A biomechanical study comparing plate-rod and plate-nail system in gap fractures, showed that maximum load was significant different between the groups, and in plate-nail it was always heavier, it occurs because of the nail bigger diameter and screws pass through nail holes. What prove that this system is stiffer than plate-rod, so because this patient has osteopenia and thin cortical bone like showed previously, we preferred to use nail than intramedullary pin. The ILN could be introduced from proximal to distal femur (antegrade or normograde) and passing through the knee (called in medicine by retrograde, although in veterinary medicine this way is called normograte too), it depends on bone conformation. Several studies used normograde via in femur from distal to proximal, especially in distal fracture. In this case, it was used this via, by the knee, because it would promote better bone stock to insert the screws, since the nail was putted as close as possible from articular surface. In conclusion, the case reported here documented that the combination of a normograde (from distal to proximal) interlock nail with a locking plate provides a rigid fixation method, promoting satisfactory functional recovery time. Further investigations should be performed using plate-nail in vivo to give to us more precise data.Keywords: biological osteosynthesis, canine, orthopaedics, retrograde nail

Eficácia de Diferentes Métodos de Proteção à Artéria Tibial Cranial, Fíbula, e Nervos Tibial e Fibular durante a TPLO: Estudo Comparativo Ex-vivo em cães

Background: Cranial cruciate ligament failure is one of the leading causes of pelvic limb lameness in dogs and one of the most recommended treatments is tibial plateau leveling osteotomy (TPLO) surgery. However, this procedure may lead to some complications as fractures of the fibula, laceration in varying degrees of the popliteal vasculature and its branches, neuropraxia, neurotmeses, among others. The goals of this study were to compare the effectiveness of 8 methods used during TPLO, to prevent damage to the cranial tibial artery, fibula, tibial and fibular nerve (surgical compresses, specific surgical retractors I and II and an osteotomy technique variation). Materials, Methods & Results: A total of 40 canine cadavers weighing 25.9 ± 3.7 kg were submitted to TPLO. Animals were previously prepared with 1: 4 barium red latex solution, to provide radiopacity of arteries surrounding the knee (n = 80). TPLO was performed using 8 methods to protect the cranial tibial artery, fibula, and tibial and fibular nerves. Each method was used in one of the knees of 5 animals. The contralateral knee was maintained as a control (without protection). The knees were radiographed in orthogonal projections before and after the osteotomies and then anatomically dissected. The evaluated structures were photographed, and the images sent to four blind evaluators (visual macroscopy) to classify the possible injuries. The highest incidence of injuries was identified when protection methods were used. However, this difference was not significant (P > 0.05). No significant differences regarding efficacy were found between all 8 protection methods. Discussion:  In this study, the total incidence of injuries following TPLO was 20% was much higher than that presented in the literature which indicates when considering only intraoperative injuries. The dogs cadavers tissue resistance and stiffened latex may have predisposed the osteotomy injury, as soft tissues with greater flexibility are less susceptible to trauma caused by the oscillatory saw. When compared to others cadaveric studies that also evaluated the efficacy of surgical dressings to protect the cranial tibial artery, during TPLO, we also find a higher incidence of damage. Maybe the limb’s position was responsible for this difference, once in the after mentioned researches the limb was positioned suspended to simulate a dorsal decubitus position and we choose the limb position with the lateral face resting on the surface of the operating table, and this may have provided extra pressure from the structures towards the osteotomy saw, increasing the occurrence of those damages. Although the present study did not reveal a significant difference for the use of protection methods, we believe that the dimensions of the compresses used herein may have contributed to a higher incidence of injuries. They probably increased the tissue trauma needed for their allocation and led to a lower positioning accuracy for the isolation of these structures.Maybe for the same reason, the specific type II surgical retractor was the only shield that, observationally, did not increase the occurrence of injuries, once less dissection was required to allocate it. The difference in geometric dimensions between the retractors may justify the superiority of the retractor II, since it allows a more careful and apparently less traumatic allocation. Performing TPLO without adopting these protection methods did not lead to a higher risk of injury to the cranial tibial artery, fibula, and tibial and fibular nerves. Keywords: osteotomy, vascular anatomy, canine stifle, TPLO.Revisão: A insuficiência do ligamento cruzado cranial é uma das principais causas de claudicação do membro pélvico em cães e a osteotomia do nivelamento do platô tibial (TPLO) um dos tratamentos mais recomendados. No entanto, este procedimento pode apresentar algumas complicações como fratura da fibula, lacerações em graus variados da vascularizaçaõ poplitea e suas ramificações, neuropraxias, neurotmeses, entre outras. Os onjetivos deste estudo foram comparar a eficácia de oito métodos de proteção utilizados durante a TPLO para prevenir danos à artéria tibial cranial, fíbula e nervos tibial e fibular (compressas cir[urgicas, afastadores cirúrgicos específicos e variação da técnica de osteotomia). Materiais, Métodos e Resultados: Quarenta cadáveres de cães pesando 25.9 ± 3.7 Kg foram submetidos à TPLO. OS animais foram previamnete preparados com solução 1:4 de látex baritado vermelho, de modo a garantir radiopacidade das artétias próximas do joelho (n=80). A TPLO foi executada utilizando oito métodos para proteção da artéria tibial cranial, fibula e nervos tibial e fibular. Cada método foi usado em apenas um dos joelhos de cinco animais. O joelho contralateral foi utilizado como controle (sem proteção). Os joelhos foram radiografados em projeções ortogonais antes e após a osteotomia e posteriormente dissecados anatomicamente. As estruturas avaliadas foram fotografadas e as imagens enviadas para quatro avaliadores cegos (macroscopia visual) para classificar possíveis injurias. A maior incidência de lesões foram observadas quando os métods de proteção foram utilizados. No entanto, esta diferença não se mostrou significativa (p>0,05). Quanto a eficácia de proteção entre os métodos, não houve diferença significativa. Discussão: Neste estudo, a incidência total de lesões após a TPLO foi de 20%, muito além da encontrada na literatura, quando consisera-se apenas as lesões transoperatorias. A resitência tecidual dos cadáveres e do latex endurecido pode ter predisposto ao dano na osteotomia, uma vez que tecidos moles possuem uma flexibilidade maior e são menos suceptiveis ao trauma causado pela serra oscilatória. Quando comparado a outros estudos cadavericos que também buscaram avaliar a eficácia de compressas cirúrgicas como método de proteção a artéria tibial cranial durante a TPLO, também encontramos uma incidência maior. Talvez, esta diferença, se deva pela posição do membro, uma vez que nos trabalhos mencionados, os pesquisadores mantiveram os membros numa posição suspensa, simulando o decubito dorsal e nós adotamos o membro com sua face lateral em contato com a mesa cirúrgica e, talvez isto, tenha gerado uma maior pressão nas estruturas contra a linha de osteotomia, aumentando a ocorrência dos danos. Apesar de o presente trabalho não mostrar diferença estatísitica significativa quanto ao uso dos métodos de proteção, acreditamos que a dimensão das compressas  utiizadas pode ter contribuidos para uma incidencia maior de lesão. Provavelmente elas aumentaram o trauma tecidual necessária para sua alocação e levaram a uma menor acurácia do posicionamento para proteção das estruturas. talvez pelo mesmo motivo, o afastador específico tipo II foi o único método que, de forma observacional, não aumentou o risco de lesão, uma vez que seu posicionamento exigia uma dissecação menor. A diferença da forma geometrica e dimensões dos afastadores pode justificar a superioridade do segundo, uma vez que permite um posicionamento mais preciso e menos traumático. Realizar a TPLO sem estes métodos de proteção não aumentaram o risco de lesão a artéria tibial cranial, fibula e nervos tibial e fibular

Eficácia de Diferentes Métodos de Proteção à Artéria Tibial Cranial, Fíbula, e Nervos Tibial e Fibular durante a TPLO: Estudo Comparativo Ex-vivo em cães

Background: Cranial cruciate ligament failure is one of the leading causes of pelvic limb lameness in dogs and one of the most recommended treatments is tibial plateau leveling osteotomy (TPLO) surgery. However, this procedure may lead to some complications as fractures of the fibula, laceration in varying degrees of the popliteal vasculature and its branches, neuropraxia, neurotmeses, among others. The goals of this study were to compare the effectiveness of 8 methods used during TPLO, to prevent damage to the cranial tibial artery, fibula, tibial and fibular nerve (surgical compresses, specific surgical retractors I and II and an osteotomy technique variation). Materials, Methods & Results: A total of 40 canine cadavers weighing 25.9 ± 3.7 kg were submitted to TPLO. Animals were previously prepared with 1: 4 barium red latex solution, to provide radiopacity of arteries surrounding the knee (n = 80). TPLO was performed using 8 methods to protect the cranial tibial artery, fibula, and tibial and fibular nerves. Each method was used in one of the knees of 5 animals. The contralateral knee was maintained as a control (without protection). The knees were radiographed in orthogonal projections before and after the osteotomies and then anatomically dissected. The evaluated structures were photographed, and the images sent to four blind evaluators (visual macroscopy) to classify the possible injuries. The highest incidence of injuries was identified when protection methods were used. However, this difference was not significant (P > 0.05). No significant differences regarding efficacy were found between all 8 protection methods. Discussion:  In this study, the total incidence of injuries following TPLO was 20% was much higher than that presented in the literature which indicates when considering only intraoperative injuries. The dogs cadavers tissue resistance and stiffened latex may have predisposed the osteotomy injury, as soft tissues with greater flexibility are less susceptible to trauma caused by the oscillatory saw. When compared to others cadaveric studies that also evaluated the efficacy of surgical dressings to protect the cranial tibial artery, during TPLO, we also find a higher incidence of damage. Maybe the limb’s position was responsible for this difference, once in the after mentioned researches the limb was positioned suspended to simulate a dorsal decubitus position and we choose the limb position with the lateral face resting on the surface of the operating table, and this may have provided extra pressure from the structures towards the osteotomy saw, increasing the occurrence of those damages. Although the present study did not reveal a significant difference for the use of protection methods, we believe that the dimensions of the compresses used herein may have contributed to a higher incidence of injuries. They probably increased the tissue trauma needed for their allocation and led to a lower positioning accuracy for the isolation of these structures.Maybe for the same reason, the specific type II surgical retractor was the only shield that, observationally, did not increase the occurrence of injuries, once less dissection was required to allocate it. The difference in geometric dimensions between the retractors may justify the superiority of the retractor II, since it allows a more careful and apparently less traumatic allocation. Performing TPLO without adopting these protection methods did not lead to a higher risk of injury to the cranial tibial artery, fibula, and tibial and fibular nerves. Keywords: osteotomy, vascular anatomy, canine stifle, TPLO.Revisão: A insuficiência do ligamento cruzado cranial é uma das principais causas de claudicação do membro pélvico em cães e a osteotomia do nivelamento do platô tibial (TPLO) um dos tratamentos mais recomendados. No entanto, este procedimento pode apresentar algumas complicações como fratura da fibula, lacerações em graus variados da vascularizaçaõ poplitea e suas ramificações, neuropraxias, neurotmeses, entre outras. Os onjetivos deste estudo foram comparar a eficácia de oito métodos de proteção utilizados durante a TPLO para prevenir danos à artéria tibial cranial, fíbula e nervos tibial e fibular (compressas cir[urgicas, afastadores cirúrgicos específicos e variação da técnica de osteotomia). Materiais, Métodos e Resultados: Quarenta cadáveres de cães pesando 25.9 ± 3.7 Kg foram submetidos à TPLO. OS animais foram previamnete preparados com solução 1:4 de látex baritado vermelho, de modo a garantir radiopacidade das artétias próximas do joelho (n=80). A TPLO foi executada utilizando oito métodos para proteção da artéria tibial cranial, fibula e nervos tibial e fibular. Cada método foi usado em apenas um dos joelhos de cinco animais. O joelho contralateral foi utilizado como controle (sem proteção). Os joelhos foram radiografados em projeções ortogonais antes e após a osteotomia e posteriormente dissecados anatomicamente. As estruturas avaliadas foram fotografadas e as imagens enviadas para quatro avaliadores cegos (macroscopia visual) para classificar possíveis injurias. A maior incidência de lesões foram observadas quando os métods de proteção foram utilizados. No entanto, esta diferença não se mostrou significativa (p>0,05). Quanto a eficácia de proteção entre os métodos, não houve diferença significativa. Discussão: Neste estudo, a incidência total de lesões após a TPLO foi de 20%, muito além da encontrada na literatura, quando consisera-se apenas as lesões transoperatorias. A resitência tecidual dos cadáveres e do latex endurecido pode ter predisposto ao dano na osteotomia, uma vez que tecidos moles possuem uma flexibilidade maior e são menos suceptiveis ao trauma causado pela serra oscilatória. Quando comparado a outros estudos cadavericos que também buscaram avaliar a eficácia de compressas cirúrgicas como método de proteção a artéria tibial cranial durante a TPLO, também encontramos uma incidência maior. Talvez, esta diferença, se deva pela posição do membro, uma vez que nos trabalhos mencionados, os pesquisadores mantiveram os membros numa posição suspensa, simulando o decubito dorsal e nós adotamos o membro com sua face lateral em contato com a mesa cirúrgica e, talvez isto, tenha gerado uma maior pressão nas estruturas contra a linha de osteotomia, aumentando a ocorrência dos danos. Apesar de o presente trabalho não mostrar diferença estatísitica significativa quanto ao uso dos métodos de proteção, acreditamos que a dimensão das compressas  utiizadas pode ter contribuidos para uma incidencia maior de lesão. Provavelmente elas aumentaram o trauma tecidual necessária para sua alocação e levaram a uma menor acurácia do posicionamento para proteção das estruturas. talvez pelo mesmo motivo, o afastador específico tipo II foi o único método que, de forma observacional, não aumentou o risco de lesão, uma vez que seu posicionamento exigia uma dissecação menor. A diferença da forma geometrica e dimensões dos afastadores pode justificar a superioridade do segundo, uma vez que permite um posicionamento mais preciso e menos traumático. Realizar a TPLO sem estes métodos de proteção não aumentaram o risco de lesão a artéria tibial cranial, fibula e nervos tibial e fibular