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.

Bone alignment after minimally invasive plate osteosynthesis of the tibia in dogs / Avaliação do alinhamento ósseo após osteossíntese minimamente invasiva com placa de tíbia em cães

ABSTRACT: This study assessed radiographically changes in tibial alignment in the frontal and sagittal planes in dogs that underwent minimally invasive plate osteosynthesis (MIPO) without the aid of image intensifiers. Radiographs of dogs with complete non-articular tibial fractures submitted to MIPO were included and evaluated, without the aid of a transoperative image intensifier and / or an association of implants. The tibial mechanical angles (mMPTA, mMDTA, mCaPTA and mCrDTA) were measured by three evaluators. The data obtained were compared with results from previously published studies. Twenty-seven animals were included in the study. The mean and standard deviation of the angular changes were as follows: mMPTA, 2.54° ± 3.10 (-1.1º to 8.7º); mMDTA, 0.03º ± 0.16 (-3.44º to 0.79º); mCaPTA, 37º ± 4.29 (-6.23º to 14.87º); and mCrDTA, 8.25° ± 5.53 (-0.2º to 17.28º). There was a negative correlation between "mCaPTA" and "mCrDTA". MIPO of the tibia without using image intensifiers and implant association can potentially cause angular changes, which can lead to clinically relevant deformities after bone healing.

RESUMO: Este estudo teve como objetivo avaliar radiograficamente as alterações no alinhamento da tíbia nos planos frontal e sagital em cães submetidos à osteossíntese minimamente invasiva com placa (MIPO) sem o auxílio de intensificadores de imagem. Foram incluídas e avaliadas radiografias de cães com fraturas completas da tíbia não articulares submetidos a MIPO, sem o auxílio de intensificador de imagem transoperatório e/ou associação de implantes. Os ângulos mecânicos tibiais (mMPTA, mMDTA, mCaPTA e mCrDTA) foram mensurados por três avaliadores. Os dados obtidos pela média de todas as avaliações foram comparados com resultados de estudos previamente publicados. Vinte e sete animais foram incluídos no estudo. A média e desvio padrão das alterações angulares foram os seguintes: mMPTA= 2,54° ± 3,10 (-1,1º a 8,7º); mMDTA= 0,03º ± 0,16 (-3,44º a 0,79º); mCaPTA= 37º ± 4,29 (-6,23º a 14,87º); e mCrDTA= 8,25 ° ± 5,53 (-0,2º a 17,28º). Houve uma correlação negativa entre "mCaPTA" e "mCrDTA". A realização de MIPO em tíbia sem o uso de intensificadores de imagem e associação de implantes pode causar alterações angulares, o que pode levar a deformidades clinicamente relevantes após a cicatrização óssea.

Capital femoral physeal dysplasia in cats submited to ostectomy of the femoral head and neck / Displasia femoral capital em felinos submetidos a ostectomia da cabeça e colo femoral

ABSTRACT: This report described pathological fracture of the femoral head (physeal dysplasia) in four male cats (three mixed breed and one Bengal), with an average age of 16 months, treated by an ostectomy of the femoral head and neck. Three cats were neutered and one entire. All presented with mild intermittent lameness in the pelvic limbs. Displacement of the femoral epiphysis and resorption of the femoral neck were present and excision of the femoral head and remaining neck was performed in all cases. Hstological examination showed mild foci of compaction and trabecular fibrosis with deposition of fibrous connective tissue, permeated by granulation tissues, consistent with the original diagosis. Limb function improved in all patients from 2 to 4 weeks postoperatively. Diagnosis of physeal dysplasia is challenging and treatment is different from acute traumatic fractures. Femoral head and neck excision was considered a good alternative in these patients.

RESUMO: Este trabalho descreve a fratura patológica da cabeça do femur (displasia fiseal) em quatro machos (três raças mistas e um Bengal), com idade média de 16 meses, que foram tratados com ostectomia da cabeça e colo femorais. Três gatos eram castrados e um inteiro. Todos apresentaram leve claudicação intermitente nos membros pélvicos. O deslocamento da epífise femoral e a reabsorção do colo femoral estavam presentes, a excisão da cabeça e colo femoral foi realizada em todos os casos. O exame histológico mostrou focos de compacteção e fibrose trabecular com deposição de tecido conjuntivo fibroso, permeado por tecidos de granulação, consistentes com o suposto diagnóstico. A função dos membros melhorou em todos os paciente entre dois a quatro semanas pós-operatório. O diagnóstico da displasia fiseal pe desafiador e o tratamento é diferente das fraturas traumáticas agudas. A excisão de cabeça e colo femoral é considerada uma boa alternativa nesses pacientes.

Biomechanical evaluation of a new femoral stem design for total hip replacement in a canine model

ABSTRACT Purpose To evaluate the biomechanical properties of a novel total hip replacement femoral stem. Methods Eight pairs of femurs from dog cadavers were used. The femurs were separated into different groups. A novel femoral stem with a convex proximal portion (Stem B) was biomechanically evaluated and compared to awell-known veterinary collared stem (Stem A). Femoral stems were inserted into the contralateral femurs from the same dog, forming 16 constructs. A flexo-compression load was applied on the axial axis of each sample. Maximum strength, deflection, stiffness, and energy absorption were analysed. Results Group B constructs showed significantly higher values (p ? 0.05) for the variables, except stiffness. The mean maximum strength was 1,347 ± 357 N for Group A and 1,805 ± 123 N for Group B (p ? 0.0069). The mean deflection was5.54 ± 2.63 mm for Group A and 10.03 ± 3.99 mm for Group B (p ? 0.0056). For the energy variable, the force was 6,203 ± 3,488 N/mm for Group A and 12,885 ± 5,056 N/mm for Group B (p ? 0.0054). Stem B had greater maximum strength, deflection, and energy. Conclusions The new stem was effective in neutralizing the impact of axial flexion-compression stresses during biomechanical tests in cadaveric models.

Comparison of intraoperative nociception and postoperative acute pain after traditional or minimally invasive ovariohysterectomy in dogs

Many variations of ovariohysterectomy techniques have been described, including the traditional one and minimally invasive procedures. Non-laparoscopic Snook hook technique is an alternative for performing minimally invasive ovariohysterectomy. Few studies have been carried out in order to assess pain in animals submitted to minimally invasive surgeries, especially involving one of the most performed surgical procedures in veterinary practice. The aim of this study was to evaluate surgical duration, intraoperative nociception and acute postoperative pain after traditional ovariohysterectomy or minimally invasive non-laparoscopic technique in dogs using Snook hook. The hypothesis is that non-laparoscopic minimally invasive ovariohysterectomy would be faster and less painful than the conventional technique. Thirty dogs were divided into Traditional Group (TG = 15) and Minimally Invasive Group (MIG = 15). Heart rate, respiratory rate, systolic blood pressure, body temperature, oxyhemoglobin saturation, end-tidal carbon dioxide concentration (ETCO2) and end-tidal isoflurane concentration were evaluated before the surgery begins (M0), during incision (M1), clamping of the first ovarian pedicle (M2), second ovarian pedicle (M3), uterine cervix (M4), abdominal suture (M5) and at the end of surgery (M6). The modified Glasgow Pain Scale was used for acute postoperative pain assessment and Visual Analogue Scale (VAS) was used to assess the sensitivity of surgical wound. The level of significance established for all statistical analysis was 5%. Statistical differences were not observed between groups considering total surgical time and postoperative acute pain intensity (P > 0.05), in spite of MIG having shorter duration of surgery. There was no statistical difference between groups considering all intraoperative parameters except respiratory rate (TG < MIG; P < 0.05) and ETCO2 (MIG < TG; P < 0.05) at the moment of traction of the first ovarian pedicle (M2). Pain assessment by VAS showed statistical difference 24h after the end of surgery (TG < MIG) (P < 0.05). Both procedures were similar regarding intraoperative nociception and acute postoperative pain. It is possible that the sensation of pain in both procedures was blocked by the effectiveness of analgesics, once they might cause an inhibition of painful behaviors limiting a possible difference in pain identification. Higher respiratory stress observed in MIG at M2 and higher pain score by VAS noted in MIG 24 h after the end of surgery can be justified by greater traction of ovarian pedicle, due to limited surgical access of minimally invasive technique. Minimally invasive ovariohysterectomy non-laparoscopic seems to be potentially faster, probably due to the smaller size of the abdominal incision, which takes less time to be closed. In the present study, both techniques were performed by an experienced surgeon, providing safe procedures, nevertheless it is important to emphasize that iatrogenic injury can be caused by surgeons non-proficient in the Snook hook technique, considering the limited visualization of anatomical abdominal structures. Data obtained indicate that traditional ovariohysterectomy and non-laparoscopic Snook hook technique promote similar intraoperative nociception and acute postoperative pain, however minimally invasive procedure is potentially faster with less surgical trauma.(AU)

Ovarian dysgerminoma causing multifocal metastases in young bitch / Disgerminoma ovariano causando metástases multifocais em cadela jovem

The ovarian neoplasias are unusual in canine species, mainly originated from germinative cells. Among these, dysgerminoma is a rare neoplasm in bitches, predominantly affecting senile and small and medium breeds. They are large, rounded, smooth surface, painless and firm in consistency. The clinical signs commonly demonstrated by patients with this neoplasia are abdominal distension and secondary signs of hyperestrogenism. The diagnosis should be based on the association of history, clinical signs, radiographic, ultrasonographic, cytological, histopathological and immunohistochemical exams. The treatment is the surgical castration and metastases are uncommon. Due to the rarity in bitches, specifically the young animals, this study aimed to describe a case of left ovarian dysgerminoma, of considerable size and adherence in adjacent organs, in a Brazilian Fila, whose showed considerable increase in abdominal volume and progressive weight loss. The diagnosis was confirmed by means of complementary x-ray, ultrasound, histopathological and immunohistochemical tests. Even with the recommended surgical treatment (castration), the patient demonstrated severe respiratory symptoms and increased abdominal volume after two months, and the complementary exams suggested pulmonary and multifocal metastases and the tutor chose euthanasia. As presented by the results, although rare in bitches, dysgerminoma should be included in the differential of ovarian neoplasias, including the young ones.

As neoplasias ovarianas são de ocorrência incomum na espécie canina, principalmente as originadas de células germinativas. Dentre estas, o disgerminoma é uma neoplasia rara em cadelas, acometendo predominantemente fêmeas senis e de raças pequenas e médias. Apresentam-se como massas grandes, arredondadas, de superfície lisa, indolores e de consistência firme. Os sinais clínicos comumente demonstrados por pacientes com este tipo neoplásico incluem distensão abdominal e sinais secundários de hiperestrogenismo. O diagnóstico deve ser baseado na associação do histórico, sinais clínicos, exames radiográficos, ultrassonográficos, citológicos, histopatológicos e imunohistoquímicos. O tratamento de escolha é a castração cirúrgica, sendo que as metástases são incomuns. Perante a raridade em cadelas, em específico as jovens, este relato teve como propósito discorrer um caso de disgerminoma ovariano esquerdo, de tamanho considerável e aderência em órgãos adjacentes, em uma Fila Brasileira, cuja sintomatologia incluiu considerável aumento de volume abdominal e emagrecimento progressivo. O diagnóstico foi confirmado por meio de exames complementares de raios-x, ultrassom, histopatológico e imunohistoquímicos. Mesmo com a instituição dotratamento cirúrgico preconizado (castração), a paciente demonstrou grave sintomatologia respiratória e aumento de volume abdominal após dois meses e, como os exames complementares foram sugestivos de metástases pulmonares e multifocais, o tutor optou pela eutanásia. Diante dos resultados, pode-se admitir que apesar de raro em cadelas, o disgerminoma deve ser incluído no diferencial das neoplasias ovarianas, incluindo as jovens.

Prospective clinical assessment of tibial tuberosity advancement for the treatment of cranial cruciate ligament rupture in dogs

Abstract Purpose: To evaluate clinically dogs that underwent tibial tuberosity advancement (TTA) six months previously. Methods: Dogs of various breeds, gender, weight, and age that had CCL rupture and underwent TTA for treatment were included in this study. Parapatellar arthrotomy was performed in all patients to assess the joint for a ruptured ligament and meniscal injury before the TTA. The appropriate cage for the TTA was chosen with planning surgery. The surgical procedure was performed according to the literature, using a modified Maquet technique. Six months after surgery, lameness during walking; muscular atrophy; crepitation, cranial drawer and tibial compression tests and quality of life based on owner's evaluation were assessed. Results: Postoperative complications were observed in only one knee (4.76%), with a surgical site seroma. The mean lameness score at walking was 0.29 (± 0.64). The mean score regarding muscular atrophy was 0.95 (± 1.56). The mean score of the cranial drawer test, in a range from 0 to 5, was 1.52 (± 1.54). The owners rated the dog's quality of life as excellent in 44%, good in 30%, and moderate in 17%. Conclusion: This clinical study supports the affirmation that patients who undergo TTA for treatment of CCL rupture have an acceptable response.

Mechanical flexural ex vivo study of osteotomized swine femurs stabilized with two types of polyamide 12 rods / Estudo mecânico de flexão, ex-vivo, de fêmures suínos osteotomizados, estabilizados com dois tipos de haste de poliamida 12

ABSTRACT: Long bone fractures are commonly in surgery routine and several bone imobilization techniques are currently available. Technological progress has enabled to use low cost materials in surgical procedures. Thus, the aim of this study was to evaluate the applicability of polyamide 12 rods, solid and hollow in swine femurs, comparing them through flexion strength. This study had as second aim to fix the locking errors, commom place in interlocking nails, once polyamide 12 allows perforation in any direction by orthopaedic screw. Six groups were used: G1 - eight whole swine femurs; G2 - eight whole swine femurs with drilled medullary canal; G3 - two solid polyamide 12 rods; G4 - two hollow polyamide 12 rods; G5 - eight osteotomized drilled swine femurs with a solid polyamide 12 rod implanted in the medullary canal and locked by four 316L stainless steel screws; and G6 - similar to G5 but using hollow rods instead of solid ones. No significant differences were observed for the modulus of rupture between solid and hollow rods, demonstrating that both rods had similar performances. These results led to the speculation that the addition of other polymers to the hollow rods could increase their strength and thus the bone-implant system. Furthermore, the comparison between G1, G5 and G6 could be analyzed using the finite element method in future. New polymeric materials may be developed based on the data from this study, strengthening the bone-implant system and making possible screws to be placed in any direction, nullifying the detrimental forces on the fracture site.

RESUMO: Fraturas em ossos longos são comumente encontradas na rotina cirúrgica e várias técnicas de imobilização óssea estão disponíveis. Com o avanço tecnológico, tornou-se viável utilizar materiais de baixo custo nos procedimentos, portanto esse estudo objetivou avaliar a aplicabilidade de hastes de poliamida 12, sólidas e vazadas, implantadas em fêmures suínos, comparando-as segundo as forças de flexão e aos erros de bloqueio, corriqueiros nesse implante, uma vez que a poliamida 12 permite sua perfuração em qualquer direção por meio de parafusos ortopédicos. Seis grupos foram usados: G1 - oito fêmures suínos íntegros; G2 - oito fêmures suínos, fresados intramedularmente; G3 - duas hastes maciças de poliamida 12; G4 - duas hastes vazadas de poliamida 12; G5 - oito fêmures suínos osteotomizados e fresados, com haste de poliamida 12 maciça implantada no canal medular e bloqueada com quatro parafusos de aço inoxidável 316L e G6 - diferente de G5 apenas por utilizar hastes vazadas. Não foram observadas diferenças significativas no módulo de ruptura entre hastes sólidas e vazadas, demonstrando que ambas apresentaram o mesmo desempenho. Estes resultados levaram à especulação de que adicionar outros polímeros às hastes vazadas aumentaria sua força e, portanto, do sistema osso-implante. Além disso, a comparação entre G1, G5 e G6 poderia no futuro ser analisada utilizando o método dos elementos finitos. Novos polímeros podem ser desenvolvidos baseando-se nos dados deste estudo, reforçando o sistema osso-implante e também possibilitando o uso de perfurações para o bloqueio no transoperatório em qualquer direção, anulando as forças deletérias atuantes no sítio de fratura.

Description of six autochthonous cases of canine visceral leishmaniasis diagnosed in Pedregulho (São Paulo, Brazil) / Descrição de seis casos autóctones de leishmaniose visceral canina, diagnosticados em Pedregulho (São Paulo, Brasil)

Visceral leishmaniasis is an infectious disease of chronic, emerging and zoonotic nature that presents various degrees of severity. In Brazil, this illness is caused by Leishmania infantum (Leishmania chagasi), which is transmitted by the bite of the sand fly Lutzomyia longipalpis, and dogs are its main reservoir. Given the increasing spread of this disease across Brazil, the aim of this study was to report on six cases of canine visceral leishmaniasis, diagnosed in June 2013, in the city of Pedregulho, State of São Paulo, considered to be a non-endemic area and free of phlebotomine sand flies. The diagnosis was based on clinical signs of the patients and additional tests (serological and parasitological). It was concluded that the diagnosis of leishmaniasis is complex because the clinical signs are similar to other systemic diseases, thus justifying the importance of parasitological test of bone marrow, considered "gold standard", in the confirmation of the disease. In addition, the area was not, until now, considered risk place, despite notification.

A leishmaniose visceral é uma doença infecciosa de caráter crônico, emergente e zoonótico, apresentando variados graus de severidade. No Brasil, tal enfermidade é causada pela Leishmania infantum (Leishmania chagasi), a qual é transmitida pela picada de flebótomo Lutzomyia longipalpis, tendo o cão como o principal reservatório. Perante a crescente distribuição da doença no território brasileiro, o objetivo do presente trabalho é relatar seis casos de leishmaniose visceral canina, diagnosticados em Junho de 2013, no município de Pedregulho, Estado de São Paulo, considerado área não endêmica e livre de flebotomíneos. O diagnóstico foi baseado nos sinais clínicos dos pacientes e exames complementares (sorológicos e parasitológicos). Concluiu-se que o diagnóstico da leishmaniose é complexo pelo fato dos sinais clínicos serem semelhantes a outras enfermidades sistêmicas, justificando assim a importância do teste parasitológico de medula óssea, considerado padrão ouro na confirmação da doença. Além disso, a área não foi, até o presente momento, considerada local de risco, apesar da notificação.

Endodontics pastes formulated with copaiba oil: action on oral microbiota and dentin bridge formation in dogs / Pastas endodônticas formuladas com óleo de copaíba: ação na microbiota bucal e formação de ponte dentinária em cães

This study analysed the effect of pastes formulated with calcium hydroxide P.A. and different vehicles (saline solution - paste A and Copaifera langsdorffii Desfon oil - paste B) on oral microorganisms and dentin bridge formation in dogs. The antimicrobial action of the pastes and their components was analysed by the minimum inhibitory concentration in agar gel technique. The components were diluted and tested on fifteen standard strains of microorganisms associated with endodontic diseases. The microorganisms were cultivated and after incubation data was analysed using One-Way ANOVA and Turkey's test (P≤0.05). Four superior incisors of ten animals were used to evaluate dentin bridge formation. Two incisors were capped with paste A (GA) and two with paste B (GB). After 90 days, the teeth were extracted for histological analysis and the degree of dentin bridge formation evaluated. Data was analysed by the Kruskal-Wallis test (P<0.05). The pastes and their components were classified in the following decreasing order of antimicrobial action: calcium hydroxide P.A., paste A, paste B and Copaifera langsdorffii Desfon oil. Calcium hydroxide P.A. showed significantly higher antimicrobial action than the pastes or their vehicles. No significant difference was observed between the two pastes in dentin bridge formation. Based on the microorganisms studied, it can be concluded that the pastes analysed showed similar antimicrobial potential but differed significantly from their individual components. No significant difference was observed in dentin bridge formation between the different pastes tested.

Foi avaliada a ação de pastas formuladas com hidróxido de cálcio P.A. e diferentes veículos (solução fisiológica - pasta A e óleo de Copaifera langsdorffii Desfon - pasta B) sobre microrganismos bucais e formação de ponte dentinária em cães. A ação antimicrobiana das pastas e de seus componentes individuais foi avaliada pela técnica da concentração inibitória mínima pela diluição em ágar. Os materiais foram diluídos e avaliados contra quinze cepas padrão de microrganismos relacionados a doenças endodônticas. Os microrganismos foram cultivados e, após a incubação, os dados foram analisados (Anova One-Way, Tukey, P≤0,05). Para a avaliação da formação de ponte dentinária, quatro incisivos superiores de dez animais foram tratados, sendo dois capeados com pasta A (GA) e dois com a pasta B (GB). Após 90 dias, os dentes foram extraídos para obtenção de cortes histológicos, com o objetivo de se avaliar o grau de formação de ponte dentinária. Os dados obtidos foram submetidos à análise estatística (Kruskal-Wallis, P<0,05). Segundo a ação antimicrobiana, os materiais foram classificados em ordem decrescente: hidróxido de cálcio P.A., pasta A, pasta B e óleo de Copaifera langsdorffii Desfon, com diferenças estatisticamente significantes entre o hidróxido de cálcio P.A., as pastas e os veículos. Ao final do estudo, observou-se que as duas pastas avaliadas foram semelhantes quanto à formação de ponte dentinária. Considerando-se os microrganismos selecionados, conclui-se que as pastas avaliadas foram semelhantes entre si em termos de potencial antimicrobiano, diferindo dos componentes individuais. Em relação à formação de ponte dentinária, não foram observadas diferenças significantes entre os dentes tratados com as diferentes pastas.

Aspectos clínicos e concentração sérica da creatina-quinase e lactato-desidrogenase em cães submetidos à fisioterapia após atrofia muscular induzida / Clinical aspects and serum concentration creatina kinase and lactate dehydrogenase in dogs submitted to physiotherapy after induced muscle atrophy

Avaliou-se a resposta de diferentes protocolos fisioterapêuticos em cães após a indução de atrofia muscular por meio da imobilização do joelho por 30 dias. Os grupos foram denominados grupo C ou controle, grupo E (massagem, movimentação passiva e eletroterapia), grupo H (massagem, movimentação passiva e hidroterapia em esteira aquática) e grupo EH (massagem, movimentação passiva, eletroterapia e hidroterapia em esteira aquática). Foram mensurados os graus de claudicação, arco do movimento, circunferência da coxa e a variação sérica das enzimas creatina-quinase e lactato-desidrogenase. De acordo com os resultados encontrados, foi possível concluir que as modalidades terapêuticas de massagem, movimentação passiva da articulação, estimulação elétrica neuromuscular e hidroterapia por caminhada em esteira aquática aceleram a recuperação clínica em cães com atrofia muscular induzida.

The response of different physiotherapeutic treatment protocols was evaluated in dogs after muscle atrophy induced by joint immobilization for 30 days. Groups were named C group or control, E group (massage, passive range of motion and neuromuscular electrical stimulation), H group (massage, passive range of motion and aquatic therapy in underwater treadmill) and EH group (massage, passive range of motion, neuromuscular electrical stimulation and aquatic therapy in underwater treadmill). It was measured the degree of lameness, range motion, thigh circumference and range of serum creatine kinase (CK) and lactate dehydrogenase (LDH). According to the results, it was possible to conclude that associated therapeutics modalities such as massage, passive range of motion of the joint, neuromuscular electrical stimulation and aquatic therapy by walking on underwater treadmill accelerate clinical recovery in dogs with induced muscle atrophy.