Locking compression plate fixation of critical-sized bone defects in sheep. Development of a model for veterinary bone tissue engineering

ABSTRACT Purpose To develop a segmental tibial bone defect model for tissue engineering studies in veterinary orthopedics using single locking compression plate (LCP) fixation and cast immobilization. Methods A 3-cm bone defect was created in the right tibia of 18 adult Suffolk sheep. A 10-hole, 4.5-mm LCP was applied to the dorsomedial aspect of the bone. Four locking screws were inserted into the proximal and three into the distal bone fragment. Operated limbs were immobilized with casts. Animals were submitted to stall rest, but were allowed to bear weight on the operated limb. During the recovery period, animals were checked daily for physiological parameters, behavior and lameness. Follow-up radiographs were taken monthly. Results Surgical procedures and postoperative recovery were uneventful. Animals adapted quickly to casts and were able to bear weight on the operated limb with no signs of discomfort or distress. No clinical or radiographic complications were detected over a 90-day follow-up period. Conclusions Surgical creation of tibial segmental bone defects followed by fixation with single LCP and cast immobilization was deemed a feasible and appropriate model for veterinary orthopedic research in tissue engineering.

Effect of low-level laser therapy on the membrane induced by the Masquelet technique at an orthotopic site in rabbits

ABSTRACT Purpose: To evaluate the low-level laser therapy (LLLT) on the membrane induced by the Masquelet technique in rabbits. Methods: Twelve Norfolk rabbits at approximately 3 months of age were used. A 1-cm segmental defect was induced in both radii, which were filled with polymethylmethacrylate cylinder. LLLT was used postoperatively in the bone defect of one of the forelimbs every 48 hours for 15 days. Six rabbits were euthanatized on third and sixth postoperative weeks. Results: In both forelimbs, radiographs showed new bone growth from radius cut ends on the third postoperative week and more advanced stage on the sixth postoperative week. Ultrasound showed induced membrane one week after the surgery. Histologically, there were no significant differences in the semi-quantitative score of inflammation intensity, total number of blood vessels, bone metaplasia, and collagen. The average thicknesses were 2,050.17 and 1,451.96 μm for control membranes and 2,724.26 and 2,081.03 μm for irradiated membranes, respectively, on third and sixth postoperative weeks. Vascular endothelial growth factor A (VEGF-A) and platelet derived growth factor (PDGF) expression were present in the induced membranes of control and irradiated forelimbs, but there was no significant difference. Conclusions: Based on assessment methods, it was not possible to demonstrate the effect of LLLT on the induced membrane.

Segmental hypoplasia of the spinal cord and syringomyelia in a calf / Hipoplasia segmentar de medula espinhal e siringomielia em um bezerro

Congenital malformations are functional and structural changes in organ systems, tissues, or organs that may develop during the embryonic or fetal phase. Spinal cord malformations, such as segmental hypoplasia of the spinal cord (SHSC) and syringomyelia, are rare in bovines. A Girolando calf from Valença, Rio de Janeiro, was admitted to the Veterinary Hospital of Universidade Federal Rural do Rio de Janeiro because of motor incoordination. Clinical evaluation revealed a 5-cm depression area in the spine at the dorsal line of the thoracic region. Neurological examination revealed reduced proprioception, pelvic limb extension with increased nociceptive activity, and reduced anal reflex. In radiographic examination, the body of the T11 vertebra had a trapezoidal wedge shape with ventral hemivertebra, probable agenesis or hypoplasia of the T11-T12 spinous processes, and fusion of the T9-T10 spinous processes. Myelography revealed extradural spinal compression caused by vertebral malformations. Necropsy showed no spinous processes (T11-T12), cranial stenosis in the medullary canal (T11-T13), and 1-3-mm pores in the white matter of the thoracic spinal cord (T8-T11). Microscopy revealed cystic dilatations in the white matter (T9-T11), cystic areas of varying sizes (T8-T9), and moderate reduction in the gray matter around the central canal of the medulla (T11-T13). Here, we reported the clinical and pathological findings of SHSC and syringomyelia in a Girolando calf. The features should be differentiated from other spinal cord syndromes. Congenital malformations are of economic importance, and their etiology and diagnosis are fundamental to disease control and progenitor-selection programs.(AU)

Malformações congênitas são alterações funcionais e estruturais dos sistemas, tecidos ou órgãos que podem ocorrer na fase embrionária ou fetal. Malformações na medula espinhal, como hipoplasia segmentar da medula espinhal (HSME) e siringomielia, possuem raras descrições em bovinos. Uma bezerra Girolando, proveniente do Município de Valença, RJ, foi atendida no Hospital Veterinário da Universidade Federal Rural do Rio de Janeiro (UFRRJ), com quadro de incoordenação motora. À avaliação clínica, na coluna vertebral, à linha dorsal da região torácica havia uma área com depressão de 5 cm. Ao exame neurológico foi observado propriocepção reduzida, extensão de membros pélvicos com aumento da atividade nociceptiva e redução de reflexo anal. Ao exame radiográfico, o corpo vertebral T11 apresentou forma trapezoidal em cunha com hemivértebra ventral, provável agenesia ou hipoplasia dos processos espinhosos T11-T12 e fusão dos processos espinhosos T9-T10. À mielografia indicou compressão medular extradural provocada pelas malformações vertebrais. À necropsia não foram observados os processos espinhosos T11-T12, o canal medular apresentou estenose cranial (T11-T13) e, na medula espinhal torácica (T8-T11) foram observados poros de 1-3 mm na substância branca. À microscopia, os segmentos T9-T11 apresentaram dilatações císticas na substância branca e os segmentos T8-T9, formações de áreas císticas de tamanhos variados; nos segmentos T11-T13 denotou-se moderada redução da substância cinzenta ao redor do canal central da medula. O presente trabalho tem o objetivo de apresentar os achados clínicos e patológicos desta bezerra Girolando com HSME e siringomielia, que devem ser diferenciadas de outras síndromes da medula espinhal. As malformações congênitas possuem importância econômica e sua etiologia e diagnóstico são fundamentais para a condução de programas de controle de doenças e seleção de progenitores.(AU)

A critical size defect model in the radius of rabbits / Modelo de falha óssea segmentar em rádio de coelhos

This study aimed to characterize a preclinical model of critical size defect (CSD) in the radius of rabbits.Twenty adults (> 7 months), female, New Zealand Rabbits, weighing between 3,5 to 5 Kg were used. They underwent a 1.5 cm long ostectomy of the diaphysis of the radius, starting 2 cm from the carpus joint. Radiographic analyses were performed at 15, 30, 60, and 90 days postoperatively, in order to evaluated bone callus formation, periosteal reaction, and bone bridge formation.The methodology allowed to precisely create bone defects of 1.5cm. Over time, no bone deposition was found at 15 days, but mild bone callus formation was observed in three animals after 60 days postoperative. At 90 days postoperatively only one rabbit presented bone consolidation radiographically, the others presented non-union. The critical bone defect proposed in this study was satisfactory, feasible with very low risk of complications.

O objetivo do presente estudo é caracterizar um modelo pré-clínico de falha óssea crítica em rádio de coelhos. Vinte coelhos adultos (> 7 meses), fêmeas, da raça New Zealand, pesando entre 3,5 e 5 kg foram utilizados. Os animais foram submetidos à ostectomia segmentar de 1,5 cm na diáfise do rádio, iniciando 2 cm acima da articulação carpo radial. As análises radiográficas foram feitas aos 15, 30, 60 e 90 dias pós-operatório, para avaliação de formação de calo ósseo, reação periosteal e formação de ponte óssea. nA metodologia permitiu a criação precisa de defeitos ósseo segmentar de 1,5 cm. Durante o experimento, não se observou deposição óssea na primeira avaliação radiográfica, porém após 60 dias foi possível visibilizar formação de calo ósseo em 3 animais. Aos 90 dias apenas um animal apresentou consolidação óssea radiograficamente; o restante apresentou não-união óssea. A falha óssea foi eficaz para estabelecer um defeito ósseo crítico além de apresentar fácil aplicação, apresentando pequeno índice de complicação.

A critical size defect model in the radius of rabbits / Modelo de falha óssea segmentar em rádio de coelhos

This study aimed to characterize a preclinical model of critical size defect (CSD) in the radius of rabbits.Twenty adults (> 7 months), female, New Zealand Rabbits, weighing between 3,5 to 5 Kg were used. They underwent a 1.5 cm long ostectomy of the diaphysis of the radius, starting 2 cm from the carpus joint. Radiographic analyses were performed at 15, 30, 60, and 90 days postoperatively, in order to evaluated bone callus formation, periosteal reaction, and bone bridge formation.The methodology allowed to precisely create bone defects of 1.5cm. Over time, no bone deposition was found at 15 days, but mild bone callus formation was observed in three animals after 60 days postoperative. At 90 days postoperatively only one rabbit presented bone consolidation radiographically, the others presented non-union. The critical bone defect proposed in this study was satisfactory, feasible with very low risk of complications.(AU)

O objetivo do presente estudo é caracterizar um modelo pré-clínico de falha óssea crítica em rádio de coelhos. Vinte coelhos adultos (> 7 meses), fêmeas, da raça New Zealand, pesando entre 3,5 e 5 kg foram utilizados. Os animais foram submetidos à ostectomia segmentar de 1,5 cm na diáfise do rádio, iniciando 2 cm acima da articulação carpo radial. As análises radiográficas foram feitas aos 15, 30, 60 e 90 dias pós-operatório, para avaliação de formação de calo ósseo, reação periosteal e formação de ponte óssea. nA metodologia permitiu a criação precisa de defeitos ósseo segmentar de 1,5 cm. Durante o experimento, não se observou deposição óssea na primeira avaliação radiográfica, porém após 60 dias foi possível visibilizar formação de calo ósseo em 3 animais. Aos 90 dias apenas um animal apresentou consolidação óssea radiograficamente; o restante apresentou não-união óssea. A falha óssea foi eficaz para estabelecer um defeito ósseo crítico além de apresentar fácil aplicação, apresentando pequeno índice de complicação.(AU)

Use of a morcellized fragment of bone as a bone graft in a femoral fracture repair / Uso de fragmento ósseo morcelizado como enxerto ósseo no reparo de fratura femoral

As one of the most frequent reasons for presentation at the orthopedic services in veterinary practice, long bone fractures need bone continuity for consolidation to take place. This case report has demonstrates the use of a morcellized fragment of bone as a bone graft in a femoral fracture with major bone loss. A mixed-breed adult cat with a segmental femoral fracture with a large longitudinal fissure in the central bone fragment was submitted to an interlocking nail osteosynthesis. During the procedure a fracture occurred along the fissure resulting in two bone fragments with significant bone loss. Fragments were morcellized and applied over the defect to act as a bone graft. By the 15th day after the surgery, the cat had a normal gait and showed no pain response, and bone consolidation occurred after 7 months. Once harvesting of humeral, femoral and tibial bone grafts can be frustrating in cats, resulting in just small amounts of bone, the morcellation of the central fragments was vital to provide sufficient graft to cover the big defect in the femoral shaft. The authors suggest that autologous fresh morcellized cortical bone fragments can be an adjunct to the treatment of comminuted fractures in cats, as an alternative to more traditional repairs of comminuted fracture.(AU)

Fraturas de ossos longos necessitam de continuidade óssea para que a consolidação ocorra. Este relato de caso tem como objetivo demonstrar o uso de um fragmento ósseo morcelizado com a função de enxerto ósseo em uma fratura de fêmur com presença de uma grande falha óssea entre os fragmentos. Um gato adulto, sem raça definida, com uma fratura múltipla em fêmur com presença de uma fissura longitudinal no fragmento central foi submetido à osteossíntese com uso de haste bloqueada. Durante o processo, ocorreu uma fragmentação a partir da fissura, o que resultou na presença de dois fragmentos ósseos com uma grande porção de perda óssea entre os dois. Os fragmentos ósseos restantes do fragmento central foram morcelizados e aplicados no defeito para atuar com enxerto ósseo. Quinze dias após a cirurgia o paciente apresentou apoio normal e ausência de dor, e consolidação óssea ocorreu em 7 meses pós operatórios. Uma vez que a coleta de enxerto nos gatos resulta em pouca quantidade de osso, a morcelização do fragmento central foi vital para promover enxerto suficiente para cobrir o defeito ósseo. Os autores sugerem que o uso de enxerto cortical autólogo fresco morcelizado pode ser um adjuvante no tratamento de fraturas cominutivas em gatos, como um tratamento alternativo à terapia convencional.(AU)

Use of a morcellized fragment of bone as a bone graft in a femoral fracture repair / Uso de fragmento ósseo morcelizado como enxerto ósseo no reparo de fratura femoral

As one of the most frequent reasons for presentation at the orthopedic services in veterinary practice, long bone fractures need bone continuity for consolidation to take place. This case report has demonstrates the use of a morcellized fragment of bone as a bone graft in a femoral fracture with major bone loss. A mixed-breed adult cat with a segmental femoral fracture with a large longitudinal fissure in the central bone fragment was submitted to an interlocking nail osteosynthesis. During the procedure a fracture occurred along the fissure resulting in two bone fragments with significant bone loss. Fragments were morcellized and applied over the defect to act as a bone graft. By the 15th day after the surgery, the cat had a normal gait and showed no pain response, and bone consolidation occurred after 7 months. Once harvesting of humeral, femoral and tibial bone grafts can be frustrating in cats, resulting in just small amounts of bone, the morcellation of the central fragments was vital to provide sufficient graft to cover the big defect in the femoral shaft. The authors suggest that autologous fresh morcellized cortical bone fragments can be an adjunct to the treatment of comminuted fractures in cats, as an alternative to more traditional repairs of comminuted fracture.

Fraturas de ossos longos necessitam de continuidade óssea para que a consolidação ocorra. Este relato de caso tem como objetivo demonstrar o uso de um fragmento ósseo morcelizado com a função de enxerto ósseo em uma fratura de fêmur com presença de uma grande falha óssea entre os fragmentos. Um gato adulto, sem raça definida, com uma fratura múltipla em fêmur com presença de uma fissura longitudinal no fragmento central foi submetido à osteossíntese com uso de haste bloqueada. Durante o processo, ocorreu uma fragmentação a partir da fissura, o que resultou na presença de dois fragmentos ósseos com uma grande porção de perda óssea entre os dois. Os fragmentos ósseos restantes do fragmento central foram morcelizados e aplicados no defeito para atuar com enxerto ósseo. Quinze dias após a cirurgia o paciente apresentou apoio normal e ausência de dor, e consolidação óssea ocorreu em 7 meses pós operatórios. Uma vez que a coleta de enxerto nos gatos resulta em pouca quantidade de osso, a morcelização do fragmento central foi vital para promover enxerto suficiente para cobrir o defeito ósseo. Os autores sugerem que o uso de enxerto cortical autólogo fresco morcelizado pode ser um adjuvante no tratamento de fraturas cominutivas em gatos, como um tratamento alternativo à terapia convencional.

Use of a morcellized fragment of bone as a bone graft in a femoral fracture repair / Uso de fragmento ósseo morcelizado como enxerto ósseo no reparo de fratura femoral

As one of the most frequent reasons for presentation at the orthopedic services in veterinary practice, long bone fractures need bone continuity for consolidation to take place. This case report has demonstrates the use of a morcellized fragment of bone as a bone graft in a femoral fracture with major bone loss. A mixed-breed adult cat with a segmental femoral fracture with a large longitudinal fissure in the central bone fragment was submitted to an interlocking nail osteosynthesis. During the procedure a fracture occurred along the fissure resulting in two bone fragments with significant bone loss. Fragments were morcellized and applied over the defect to act as a bone graft. By the 15th day after the surgery, the cat had a normal gait and showed no pain response, and bone consolidation occurred after 7 months. Once harvesting of humeral, femoral and tibial bone grafts can be frustrating in cats, resulting in just small amounts of bone, the morcellation of the central fragments was vital to provide sufficient graft to cover the big defect in the femoral shaft. The authors suggest that autologous fresh morcellized cortical bone fragments can be an adjunct to the treatment of comminuted fractures in cats, as an alternative to more traditional repairs of comminuted fracture.

Fraturas de ossos longos necessitam de continuidade óssea para que a consolidação ocorra. Este relato de caso tem como objetivo demonstrar o uso de um fragmento ósseo morcelizado com a função de enxerto ósseo em uma fratura de fêmur com presença de uma grande falha óssea entre os fragmentos. Um gato adulto, sem raça definida, com uma fratura múltipla em fêmur com presença de uma fissura longitudinal no fragmento central foi submetido à osteossíntese com uso de haste bloqueada. Durante o processo, ocorreu uma fragmentação a partir da fissura, o que resultou na presença de dois fragmentos ósseos com uma grande porção de perda óssea entre os dois. Os fragmentos ósseos restantes do fragmento central foram morcelizados e aplicados no defeito para atuar com enxerto ósseo. Quinze dias após a cirurgia o paciente apresentou apoio normal e ausência de dor, e consolidação óssea ocorreu em 7 meses pós operatórios. Uma vez que a coleta de enxerto nos gatos resulta em pouca quantidade de osso, a morcelização do fragmento central foi vital para promover enxerto suficiente para cobrir o defeito ósseo. Os autores sugerem que o uso de enxerto cortical autólogo fresco morcelizado pode ser um adjuvante no tratamento de fraturas cominutivas em gatos, como um tratamento alternativo à terapia convencional.

Uso de enxerto autógeno de fáscia lata no tratamento de defeito segmentar crônico do tendão calcâneo comum em felino doméstico / Use of autogenous fascia lata graft in the treatment of chronic segmental defect of the common calcaneus tendon in domestic feline

Background: The common calcaneus tendon is formed by the common tendon of the femoral biceps muscle, tendon of the superficial digital flexor muscle and gastrocnemius muscle tendon, and its rupture is related to acute traumas in small animals. Among some applications described, surgical repair can be adopted in the correction of tendon ruptures and the use of grafts may be indicated in some severe lesions, where it is not possible to perform tenorrhaphy. This study aims to report the case of a feline with rupture of the common calcaneus tendon in which the tenorrafia associated with the autogenous fascia lata graft was performed as adjuvant to the cicatrization of the same.Case: A 24-month-old, undefined male feline with approximately 3 kg was treated at the FCAV Veterinary Hospital, UNESP Jaboticabal, State of São Paulo, Brazil, with a history of falling, for approximately two weeks, and has since plantigrade posture. Upon physical examination, it was possible to identify a discontinuity of the common calcaneus tendon. The radiographs were performed, which did not show any bone changes. A hemogram and biochemical profile were performed, which were within normal limits. The patient underwent surgery, and a complete lesion of the common calcaneus tendon was identified, with a chronic aspect. Approximation of the stumps was impossible, so a flap of fascia lata, about two centimeters long and one centimeter wide, was removed, which was used as a bed and tendon support for tendon growth. After removal all of the present fibrosis, the tendon stumps were approximated by means of modified Kessler suture with mononylon thread, and fascia lata flap of the ipsilateral limb was sutured with separate single points in both tendon ends and in their lateral and medial portion. In the tibiotarsic joint, the external skeletal fixator type II was used for immobilization, during a period of 30 days.[...]

Uso de enxerto autógeno de fáscia lata no tratamento de defeito segmentar crônico do tendão calcâneo comum em felino doméstico / Use of autogenous fascia lata graft in the treatment of chronic segmental defect of the common calcaneus tendon in domestic feline

Background: The common calcaneus tendon is formed by the common tendon of the femoral biceps muscle, tendon of the superficial digital flexor muscle and gastrocnemius muscle tendon, and its rupture is related to acute traumas in small animals. Among some applications described, surgical repair can be adopted in the correction of tendon ruptures and the use of grafts may be indicated in some severe lesions, where it is not possible to perform tenorrhaphy. This study aims to report the case of a feline with rupture of the common calcaneus tendon in which the tenorrafia associated with the autogenous fascia lata graft was performed as adjuvant to the cicatrization of the same.Case: A 24-month-old, undefined male feline with approximately 3 kg was treated at the FCAV Veterinary Hospital, UNESP Jaboticabal, State of São Paulo, Brazil, with a history of falling, for approximately two weeks, and has since plantigrade posture. Upon physical examination, it was possible to identify a discontinuity of the common calcaneus tendon. The radiographs were performed, which did not show any bone changes. A hemogram and biochemical profile were performed, which were within normal limits. The patient underwent surgery, and a complete lesion of the common calcaneus tendon was identified, with a chronic aspect. Approximation of the stumps was impossible, so a flap of fascia lata, about two centimeters long and one centimeter wide, was removed, which was used as a bed and tendon support for tendon growth. After removal all of the present fibrosis, the tendon stumps were approximated by means of modified Kessler suture with mononylon thread, and fascia lata flap of the ipsilateral limb was sutured with separate single points in both tendon ends and in their lateral and medial portion. In the tibiotarsic joint, the external skeletal fixator type II was used for immobilization, during a period of 30 days.[...](AU)

Efeito da irradiação com laser de baixa intensidade na qualidade de membrana induzida pela técnica de Masquelet em coelhos

O estudo avaliou a influência da irradiação laser de baixa intensidade no desenvolvimento e características da membrana de Masquelet, induzida de forma ortotópica em coelhos. Foram utilizados 12 coelhos Norfolk com idade média de três meses. Em ambos os membros torácicos, foi induzida uma falha óssea segmentar de 1,0 cm de comprimento no rádio, a qual foi preenchida com um cilindro de cimento ortopédico. No período pós-operatório, em um dos membros a falha recebeu terapia laser de baixa intensidade (2J de energia) a cada 48 horas, durante 15 dias. As regiões das falhas segmentares foram avaliadas por exames ultrassonográficos e radiográficos. Seis animais foram submetidos à eutanásia com três semanas e seis com seis semanas de pós-operatório, para se proceder os exames histológicos e imuno-histoquímico das membranas de Masquelet. Em ambos os membros, radiograficamente notou-se na terceira semana de pós-operatório a presença de proliferação óssea ativa partindo das extremidades ósseas, sendo que na sexta semana o processo evolutivo mostrou-se em estágio mais avançado. O exame ultrassonográfico visibilizou, em ambos os membros, a presença da membrana induzida com uma semana de pós-operatório. Histologicamente não ocorreram diferenças estatísticas relativas ao escore semiquantitativo da intensidade de inflamação, número total de vasos sanguíneos, metaplasia óssea e colágeno. As espessuras médias das membranas induzidas foram 2050,17 µm e 1451,96 µm no membro controle e 2724,26 µm e 2081,03 µm no membro irradiado com laser, respectivamente na terceira e sexta semanas de pós-operatório. A expressão de VEGF e de PDGF foi presente nas membranas do membro controle e naquelas irradiadas, sem diferenças estatísticas. Foi possível concluir que pelos métodos de avaliação utilizados não foi possível comprovar estatisticamente a influência da irradiação laser de baixa intensidade sobre a membrana de Masquelet.

This study aimed to evaluate the influence of low-intensity laser irradiation on the development and characteristics of the Masquelet membrane induced in orthotopic site in rabbits. Twelve Norfolk rabbits, mean age of 3 months were used. In both forelimbs, a segmental bone defect of 1.0 cm length was induced in the radius, which was filled with a cylinder of polymethylmethacrylate bone cement. Low-level laser therapy was used postoperatively in the bone defect of one of the forelimbs by point technique (2J energy) every 48 hours for 15 days. The bone defect were evaluated by ultrasound and radiographic examinations. Six rabbits were submitted to euthanasia at three weeks postoperatively and six rabbits at six weeks postoperatively to perform the histological and immunohistochemical examinations of the Masquelets membranes. In both forelimbs, radiographs showed new bone growth from the cut ends of the radius on third postoperative week, and more advanced stage on sixth postoperative week. Sonographic examination identified in both forelimbs the presence of the induced membrane one week after the surgery. Histologically, there were no statistically significant differences in semi-quantitative score of inflammation intensity, total number of blood vessels, bone metaplasia and collagen. The average thickness of the induced membranes was 2050.17 µm and 1451.96 µm in the control forelimb and 2724.26 µm and 2081.03 µm in the laser irradiated limb, respectively on third and sixth postoperative weeks. VEGF and PDGF expression were present in the induced membranes of the control and irradiated forelimbs, but showed no significant difference. In conclusion, based on assessment methods was not possible to demonstrate statistically the influence of low-intensity laser irradiation in the Masquelet membrane.

COMPÓSITO PROTOTIPADO 3D NA RECONSTRUÇÃO DE FALHA CRÍTICA EM RÁDIO DE COELHOS (Oryctolaguscuniculus)

A proposta deste estudo foi utilizar a tecnologia de impressoras 3D para obtenção de substitutos ósseos para reconstrução de falhas segmentares críticas em rádio de coelhos. Foramutilizados 60 coelhos da raça Nova Zelândia nos quais realizou-se ostectomia segmental de 1,5 cm no rádio direito. Os animais foram divididos em três grupos, onde o grupo controle (GI n= 20) foi submetido àostectomia e não recebeu nenhum tratamento. O grupo enxerto (GII n = 20) foi submetido à ostectomia e reconstrução da falha óssea por meio de enxerto autólogo proveniente da asa do ílio.Ogrupo implante (GIII n=20) foi submetido à reconstrução óssea pela implantação de próteses impressas por impressora 3D constituídas de ácido polilático (PLLA) ehidroxiapatita (HA). Os implantes foram preparados com base na imagem de tomografia computadorizada obtidas do membro do próprio animal. Os animais foram avaliados clinicamente nos momentos pós-operatório 7, 15, 30, 60 e 90 dias. Radiografias em duas projeções foram efetuadas nos dias 15, 30, 60 e 90 após a cirurgia, de acordo com os subgrupos T1, T2, T3 e T4, respectivamente. Ao final das avaliações radiográficas, os animais foram submetidos à eutanásia e o segmento ósseo de interesse encaminhado para análise histopatológica. Clinicamente, o grupo enxerto (grupo II) apresentou menor claudicação, edema, dor e complicações nas feridas cirúrgicas quando comparado aos grupos controle e grupo implante. Nas avaliações radiográficas a reação periosteal, formação de calo ósseo e ponte óssea também foram superiores no grupo II quando comparado aos outros grupos. No estudo histopatológico fibrose, osteogênese e condrogênese foi similar em todos os grupos. No entanto, a presença de congestão, hemorragia e inflamação foram maiores no grupo implante. Esses resultados sugerem que os implantes impressos apresentam boas propriedades biomecânicas que em estudos futuros podem ser associados às propriedades biológicas do enxerto ósseo criando-se um novo implante que apresente características osteocondutivas e osteogênicas, como por exemplo, a associação de PLLA, HA e células vivas.

The purposeofthisstudywasto use the 3D printingtechnologytoobtain a bonesubstitute for reconstructionofcritical segmental bonefailuresof 1.5cm in rabbits radio. The animalsweredividedinto 3 groups: Group I (n=20) orcontrolgroup, Group II (n=20) orgraftgroupandGroup III (n=20) orimplantgroup. Ongroup I, therabbitsweresubmittedtoostectomyreceivingno treatment. Ongroup II, thebonedefectwastreatedwithautologousgraftfromtheiliumcrest. Ongroup III,reconstructionoccurredusing athree-dimensional printedhydroxyapatiteandPoly-L-lacticacid(PLLA)implant. The implantswerepreparedusing 3D imagingbasedonthecomputedtomographyobtainedfromeach animal. Clinicalevaluationwereconductedpostoperativelyonday 7, 15, 30, 60 e 90. Radiographs in twoprojectionsweretakenondays 15, 30, 60 and 90 postoperative, accordingtothesubgroups T1, T2, T3 and T4, respectively.Afterradiographicevaluation, theanimalsweresubmittedtoeuthanasiaandthebonesegmentwasreferred for histopathologicalanalysis. Clinically, group II presentedlesslameness, edema, painandcomplicationsonthesurgicalwoundwhencomparedtothecontrolandimplantgroups. Onradiographicevaluation, periosteal reaction, bonecallusformationandbone bridge werealso superior in group II whencomparedtotheothersgroups.Histopathologicalstudyshowedthatfibrosis, osteogenesisandchondrogenesiswere similar in allgroups. However, thepresenceofcongestion, hemorrhageandinflammationwerehigher in theimplantgroup.Theseresultsindicatethatbiomechanicalcapacityoftheimplantandbiologicalpropertiesofthegraftboneshouldbeassociatedbycreating a new implantthatpresentsosteoconductiveandosteogeniccharacteristics, such as a bonesubstituteprintedusing PLLA andhydroxyapatiteenrichedwithliving cells.

Características da membrana induzida pela técnica de Masquelet em defeito ósseo do rádio em galinhas

O presente estudo visou avaliar temporalmente a formação e a qualidade da membrana induzida de Masquelet, tendo por modelo uma falha óssea segmentar induzida no rádio de galinhas. Foram utilizadas 16 galinhas saudáveis, com um ano de idade e massa corpórea média de 1,45 kg. Sob anestesia geral inalatória, foi induzido defeito segmentar de 1,5 cm no rádio esquerdo, o qual foi preenchido com cimento ósseo na fase pastosa. Os defeitos foram avaliados por meio de exames radiográficos e ultrassonográficos, imediatamente após o procedimento cirúrgico e aos sete, 15, 21 e 30 dias de pós-operatório. Para a avaliação histológica das membranas induzidas, uma ave foi submetida à eutanásia aos sete dias (estudo piloto) de pós-operatório e cinco aves aos 15, 21 e 30 dias de pós-operatório. No exame radiográfico do pós-operatório imediato foi possível verificar a presença do cimento ocupando a falha óssea segmentar, como uma massa radiopaca, com variações de intensidade. Com 30 dias de pós-operatório já foi evidente a presença de nova formação óssea partindo de ambas as extremidades fraturadas. Pelo exame ultrassonográfico, as membranas mostraram a maior formação de vascularização aos 30 dias de pós-operatório. Pela avaliação histológica a membrana aos sete e 15 dias de pós-operatório tinha três zonas distintas, porém aos 15 dias havia presença de neovascularização, fibras colágenas organizadas e diminuição de células inflamatórias. Aos 21 dias após a cirurgia houve uma perda de delimitação das camadas, com formação de metaplasia cartilaginosa e óssea, e aos 30 dias de pós-operatório havia completa mineralização da membrana. Foi possível concluir que entre os momentos avaliados, todos mostraram a formação da membrana induzida de Masquelet em galinhas, porém com 15 dias de pós-operatório se detectou a melhor qualidade da membrana, visando o segundo estágio cirúrgico para reconstrução óssea.

This study aimed to evaluate the formation and quality of the induced membrane in Masquelet's technique, using a segmental bone defect induced in the chickens radius. Sixteen healthy domestic chickens, 1 year old and weighing 1.45 kg were used. Under general anesthesia, a 1.5-cm segmental bone defect was induced in the left radius, which was filled with bone cement during its pasty polymerization phase. The bone defects were evaluated by plain X-rays and ultrasounds, immediately after surgery and at seven, 15, 21 and 30 days postoperatively. One bird was euthanized at 7 days after surgery (pilot study), and five birds were euthanized at 15, 21 and 30 days postoperatively for histological evaluation of the induced membranes. Immediate postoperative radiographic examination showed the presence of cement that occupied the segmental bone defect, as a radiopaque mass, with intensity variations. Thirty days after surgery the presence of new bone formation at the fractured extremities was evident. Ultrasound evaluation showed that the induced-membrane had the highest rate of vascularization at 30 days post-surgery. Histologically, the induced-membrane had three distinct zones at 7 and at 15 days postoperatively, but day 15 had neovascularization, organized collagen fibers and reduced of inflammatory cells. At 21 days after surgery, the zones were less defined and there was cartilage and bone metaplastic areas. At 30 days postoperative diffuse mineralization of the membrane was observed. In conclusion, all time periods of evaluation showed the formation of the induced membrane, but the highest quality of the membrane was detected at 15 days postoperatively, aiming second-stage surgery for bone reconstruction.

Multiple segmental spinal cord hypoplasia in a cat / Hipoplasia medular segmentar múltipla em um felino doméstico

Background: The nervous system is one of the most affected by congenital malformations. These can occur during neural tube formation or failed neurogenesis. Segmental spinal cord hypoplasia commonly involves two or three spinal segments in the thoracolumbar region. It is characterized by incomplete formation of the spinal cord and may also be followed by spine column malformations. Clinical signs usually include functional impairment of the hindlimbs. Diagnosis is based on history, clinical signs, age, radiographs and is confi rmed with necropsy and histopathological fi ndings. There is no treatment for this condition and the animals present low life quality. This paper aims to report the clinical, radiographic and histopathological aspects of multiple segmental spinal cord hypoplasia in a domestic cat. Case: A 52-days-old, female, Persian breed, domestic cat weighing 0.55 kg was treated presenting a history of pelvic limb paraplegia associated with urinary and fecal incontinence since birth. On clinical examination there were fl accid paraplegia of hind limbs associated with absence of proprioception, anal refl ex and tone and postural defi cits. Also, all spinal refl exes of pelvic limbs and deep and superfi cial pain were absent. There was no clinical history of muscular tremors, nystagmus, seizures or other central nervous system signs. The other animals of the litter showed...(AU)

Multiple segmental spinal cord hypoplasia in a cat / Hipoplasia medular segmentar múltipla em um felino doméstico

Background: The nervous system is one of the most affected by congenital malformations. These can occur during neural tube formation or failed neurogenesis. Segmental spinal cord hypoplasia commonly involves two or three spinal segments in the thoracolumbar region. It is characterized by incomplete formation of the spinal cord and may also be followed by spine column malformations. Clinical signs usually include functional impairment of the hindlimbs. Diagnosis is based on history, clinical signs, age, radiographs and is confi rmed with necropsy and histopathological fi ndings. There is no treatment for this condition and the animals present low life quality. This paper aims to report the clinical, radiographic and histopathological aspects of multiple segmental spinal cord hypoplasia in a domestic cat. Case: A 52-days-old, female, Persian breed, domestic cat weighing 0.55 kg was treated presenting a history of pelvic limb paraplegia associated with urinary and fecal incontinence since birth. On clinical examination there were fl accid paraplegia of hind limbs associated with absence of proprioception, anal refl ex and tone and postural defi cits. Also, all spinal refl exes of pelvic limbs and deep and superfi cial pain were absent. There was no clinical history of muscular tremors, nystagmus, seizures or other central nervous system signs. The other animals of the litter showed...

USO DO DECANOATO DE NANDROLONA NO TRATAMENTO DA NÃO UNIÃO ÓSSEA EM FRATURAS DO RÁDIO - ESTUDO EXPERIMENTAL EM COELHOS (Oryctolagus cuniculus)

O objetivo da pesquisa foi avaliar a eficácia do Decanoato de Nandrolona (DN) em fraturas do rádio após indução da não união óssea por defeito segmentar. Foram utilizados 47 coelhos, da raça Nova Zelândia Branco, com peso médio de 3,8 kg, divididos aleatoriamente em grupos de 8 animais. Os grupos Controle Machos (GCM) e Controle Fêmeas (GCF) foram submetidos à eutanásia aos 45 dias, os grupos Nandrolona Machos (GNM) e Nandrolona Fêmeas (GNF) tratados com aplicações semanais de DN na dose de 10mg/kg, via intramuscular (IM) durante 4 semanas. Os Grupos Placebo Machos (GPM) e Grupo Placebo Fêmeas (GPF), tratados com aplicações semanais de NaCl 0,9% (IM), durante o mesmo período. Foi realizado exame radiográfico após a cirurgia e aos 15, 30, 45, 60, 75 e 90 dias. Os animais dos grupos GNM, GNF, GPM e GPF foram submetidos à eutanásia aos 90 dias. Realizou-se exame de densitometria óssea do rádio dissecado após a eutanásia em todos os grupos, bem como análise histológica. Para as variáveis não-paramétricas utilizou-se o teste de Kruskal-Wallis. Para as variáveis paramétricas foi utilizado o teste Shapiro-Wilk, ambos a 5% de significância. Radiograficamente, os grupos tratados com DN apresentaram média de escore superior aos demais grupos na formação de calo ósseo. Na análise densitométrica, também foi observada uma melhora significativa ao parâmetro de composição mineral óssea (BMC) nos grupos GNM e GNF. Os machos apresentaram maiores médias para os parâmetros conteúdo mineral ósseo local (BMCL) e densidade mineral ósseal local (BDML). Não houve diferença estatística significativa na avaliação histológica.

The aim of research was to evaluate Nandrolone Decanoate (DN) efficacy in radius fractures after induction of bone nonunion by segmental defect. Forty-seven New Zealand White rabbits weighing 3.8 kg were randomly divided into groups of 8 animals. Male Control Group (GCM) and Female Control Group (GCF) were euthanized at 45 days. Nandrolone Male Group (GNM) and Nandrolone Female Group (GNF) treated with weekly doses of DN (10mg/kg) intramuscular (IM) for 4 weeks. Placebo Males Groups (GPM) and Placebo Females Group (GPF) treated with weekly applications of 0.9% NaCl (IM) during the same period. A radiographic examination was performed after surgery and at 15, 30, 45, 60, 75 and 90 days. The groups GNM, GNF, GPM and GPF were euthanized at 90 days. Bone densitometry of dissected radius after euthanasia was performed in all groups as well as histological analysis. For nonparametric variables was used Kruskal-Wallis test. For parametric variables used Shapiro-Wilk test, both at 5% significance level. Radiographically groups were treated with DN presented higher average score than other groups in bone callus formation. In densitometric analysis a significant improvement in bone mineral composition (BMC) was also observed in GNM and GNF groups. Males showed higher media for local bone mineral content (BMCL) and local bone mineral density (BDML). There was no statistically significant difference in histological evaluation.

Aspecto radiológico e macroscópico de matriz óssea mineralizada heteróloga fragmentada e polimetilmetacrilato autoclavados em falha óssea de tíbia de coelho / Radiological and macroscopic aspects of autoclaved heterologous fragmented mineralized bone matrix and polymethylmethacrylate in bone defect in tibia of rabbits

Foi realizada falha segmentar com 6mm de diâmetro na região metafisária medial de tíbias de 12 coelhos, onde foi implantado uma associação de micro e macrofragmentos de matriz óssea cortical heteróloga fragmentada conservada em glicerina (98%) e polimetilmetacrilato autoclavados, para a sua reconstrução, e avaliados radiológica e macroscopicamente aos 30, 60, 90 e 120 dias. Houve adesão, em relação ao tempo, dos micro e macrocompósitos ao leito receptor, em 100% dos casos, mostrando ser biologicamente biocompatível, pois promoveram a reparação de falhas ósseas, sem sinais de infecção, migração e/ou rejeição, podendo, dessa forma, ser mais uma opção como substituto para preencher grandes defeitos ósseos.(AU)

A segmental defect of 6mm diameter was performed in the medial metaphyseal region of the tibia of 12 rabbits. For the bone defect reconstruction there was implanted a combination of micro and macro fragments of heterologous fragmented cortical bone matrix preserved in glycerin (98%) and polymethylmethacrylate, both autoclaved. Radiological and macroscopic evaluation was performed at 30, 60, 90 and 120 days. Adhesion in relation to time of the micro and macro composites to the recipient bed was observed in 100% of the cases. This showed that this implant is biologically biocompatible, since it promoted bone defects repair, with no signs of infection, migration and/or rejection. In this way, this implant can be classified as one more option of substitute to fill large bone defects.(AU)

Tomographic imaging of fragmented cortical bone heteroimplant and methylmethacrylate in segmental bone defect of rabbit tibia

PURPOSE: To evaluate the performance of composites consisting of fragmented cortical bone heteroimplant in association with methylmethacrylate preserved in 98% glycerin, in segmental bone defect of rabbit tibia medial metaphysis. METHODS: In this study were used twelve adult New Zealand rabbits, divided into three groups of four animals each: G30 (30 days), G60 (60 days) and G90 (90 days). The bone defects previously created in the tibia were filled with composites and both were evaluated by cone-beam computed tomography, immediately after surgery and after 30, 60, and 90 days. RESULTS: The composites fulfilled and remained in the sites of bone defects in all cases and were not registered signals of infection, migration or rejection. CONCLUSIONS: The implanted composites promoted the bone defects repair without signals of infection and/or rejection. The composites are one more option for bone defects repair.

Tomographic imaging of fragmented cortical bone heteroimplant and methylmethacrylate in segmental bone defect of rabbit tibia

PURPOSE: To evaluate the performance of composites consisting of fragmented cortical bone heteroimplant in association with methylmethacrylate preserved in 98% glycerin, in segmental bone defect of rabbit tibia medial metaphysis. METHODS: In this study were used twelve adult New Zealand rabbits, divided into three groups of four animals each: G30 (30 days), G60 (60 days) and G90 (90 days). The bone defects previously created in the tibia were filled with composites and both were evaluated by cone-beam computed tomography, immediately after surgery and after 30, 60, and 90 days. RESULTS: The composites fulfilled and remained in the sites of bone defects in all cases and were not registered signals of infection, migration or rejection. CONCLUSIONS: The implanted composites promoted the bone defects repair without signals of infection and/or rejection. The composites are one more option for bone defects repair.(AU)

ÓXIDO DE GRAFENO NO REPARO DE DEFEITO ÓSSEO SEGMENTAR EXPERIMENTAL EM RÁDIO DE COELHOS

Estudos recentes com óxido de grafeno têm demonstrado efeitos promissores na consolidação óssea. Objetivou-se com este estudo avaliar a consolidação de defeitos ósseos segmentares em rádios de coelhos tratados com óxido de grafeno. Foram utilizados 24 coelhos brancos da raça Nova Zelândia adultos com um peso de 3 ± 0,5 kg, 12 machos e 12 fêmeas, os quais foram submetidos à indução de defeitos ósseos em ambos os rádios. Os animais foram divididos aleatoriamente em dois grupos: esponja de colágeno + óxido de grafeno = GGO, n = 12 (6 machos e 6 fêmeas) e esponja de colágeno = GEC, n = 12 (6 machos e 6 fêmeas). Em ambos os grupos, o membro direito dos animais foi submetido apenas ao defeito ósseo e não receberam tratamento, sendo denominados: Esponja de colágeno + óxido de grafeno controle = GGOC e Esponja de colágeno controle = GECC. O defeito ósseo no membro esquerdo foi preenchido com os seguintes biomateriais, conforme cada grupo: esponja de colágeno hidrolisada liofilizada + óxido de grafeno (GGO) ou esponja de colágeno hidrolisada liofilizada (GEC). Para avaliação entre os grupos, foram realizadas análises radiológicas pré-operatória, pós-operatória e a cada 15 dias após a indução do defeito, obtendo-se a última análise aos 60 dias. Após 30 dias, seis animais de cada grupo foram submetidos a eutanásia para análises de energia de raios-x no defeito ósseo, fornecidas com auxílio da imagem da microtomografia computadorizada de raios-x. Após 60 dias estas análises foram repetidas nos demais. Com auxílio das análises estatísticas não significativas (P>0,05), conclui-se que a utilização do óxido de grafeno no processo de reparo ósseo não apresentou diferença detectável nas avaliações quando comparado com a esponja de colágeno ou com o defeito ósseo controle.

In recent studies, graphene oxide has shown promising effects on bone healing. This study aimed to evaluate the healing of segmental bone defects in rabbit radii treated with graphene oxide. Bone defects were induced on both radio of twenty-four adult New Zealand White rabbits weighing 3 ± 0.5 kg, 12 males and 12 females. The animals were randomly divided into two groups: collagen sponge + graphene oxide (GGO), n = 12 (6 males and 6 females) and collagen sponge (GEC), n = 12 (6 males and 6 females). In both groups, the right limb of the animals was submitted only to the bone defect and did not receive treatment, being denominated: collagen sponge + graphene oxide control (GGOC) and collagen sponge control (GECC). The bone defect induced on the left limb was filled with the following biomaterials, according to each group: lyophilized hydrolyzed collagen sponge + graphene oxide (GGO) or lyophilized hydrolyzed collagen sponge (GEC). For evaluation between groups, radiological analyzes were performed preoperatively, postoperatively and every 15 days after the defect induction, the last analysis was made on the 60th day. On the 30th day, six animals from each group were submitted to euthanasia and X-ray energy analysis, using computerized x-ray microtomography image. On the 60th day, the remaining animals were analyzed. Through non-significant statistical analyzes (P> 0.05) we concluded that the use of graphene oxide in the bone repair process showed no detectable difference in evaluations when compared to the collagen sponge or to the control.