RESUMO

Hyperbaric oxygen therapy (HBOT) has proven successful in wound healing. However, its potential effects on anterior cruciate ligament (ACL) injuries remain uncertain. This study aimed to investigate the impact of HBOT on graft healing following ACL reconstruction in rabbits. Male New Zealand rabbits underwent ACL reconstruction and were randomly divided into two groups: the HBOT group and the ambient air group. The HBOT group received 100% oxygen at 2.5 atmospheres absolute for 2 h daily for 5 consecutive days, starting from the first day after surgery. The ambient air group was maintained in normal room air throughout the entire period. After 12 weeks following the surgery, animals were euthanized, and their knees were harvested for analysis. The HBOT group demonstrated superior graft maturation and integration in comparison to the ambient air group, as evidenced by lower graft signal intensity on magnetic resonance imaging, decreased femoral and tibial tunnel size, and higher bone mineral density values on high-resolution peripheral quantitative computed tomography scans. Additionally, biomechanical testing indicated that the HBOT group had greater load to failure and stiffness values than the ambient air group. In conclusion, the adjuvant use of HBOT improved ACL graft maturation and integration, reduced tunnel widening, and enhanced the biomechanical properties of the graft. These results may provide important insights into the potential clinical application of HBOT as a therapeutic intervention to enhance graft healing after ACL reconstruction, paving the way for further research in this area.

Assuntos

RESUMO

ABSTRACT Objective: Throughout microsurgical anastomosis, many surgeons use topical vasodilators in order to reduce pathological vasospasm. It was carried out an experimental study comparing the effectiveness of topical use of Nitroglycerin, Papaverine, Magnesium sulfate over a control group in the femoral artery and vein of rats, in reducing prolonged vasospasm. Methods: Randomized comparative experimental study in 15 rats, divided into four groups. The external diameter of the vases soaked in the randomized solution was measured. For statistical analysis, it was calculated the percentual increase in the external diameter of the vessels. Results: A statistically significant increase in arterial dilation was observed after 10 minutes of topical application of 10% magnesium sulfate compared to the control group, with p = 0.044 . No other drug showed a vasodilator effect superior to the control group. Magnesium sulfate at 10% is still not used in microsurgery and costs 15 times less than papaverine, the standard drug for topical vasodilation in clinical cases at our service. Conclusion: Magnesium sulfate had better vasodilating effects over the control group after 10 minutes of arterial microanastomosis. None of the tested drugs have presented superior vasodilating effects over each other nor the control group after venous microanastomosis. Level of evidence II, Experimental study, Randomized Trial.

RESUMO Objetivo: Durante a anastomose microcirúrgica, muitos cirurgiões utilizam vasodilatadores tópicos para reduzir o vasoespasmo prolongado patológico, assim reduzindo o risco de complicações vasculares. Entretanto, ainda faltam dados experimentais para identificação da droga padrão-ouro para vasodilatadores tópicos em microcirurgia e sua avaliação de análise de custo, já que a droga geralmente utilizada para este objetivo é baseada, na maior parte dos casos, na experiência do cirurgião. Métodos: Foi realizado um estudo experimental comparativo randomizado, avaliando a eficácia do uso tópico de Nitroglicerina, Papaverina e Sulfato de Magnésio em relação a um grupo controle, na redução do vasoespasmo na artéria e veia femoral de ratos. Foram avaliados o diâmetro externo dos vasos embebidos em solução randomizada dos fármacos para vasodilatação. Após cálculo do aumento percentual no diâmetro externo dos vasos, foi realizada análise estatística. Resultados: Observou-se aumento estatisticamente significativo da dilatação arterial após 10 minutos de aplicação tópica de sulfato de magnésio a 10% em relação ao grupo controle, com p = 0,044. Nenhuma outra droga apresentou efeito vasodilatador superior ao grupo controle. O sulfato de magnésio a 10% ainda não é utilizado em microcirurgia e apresenta custo até 15 vezes menor quando comparado com a papaverina, droga padrão para vasodilatação tópica em casos clínicos em nosso serviço. Conclusão: O sulfato de magnésio apresentou melhor efeito vasodilatador quando comparado ao grupo controle, após 10 minutos da microanastomose arterial. Nenhum dos fármacos testados apresentou efeito vasodilatador superior após a microanastomose venosa. Nível de Evidência II, Estudo experimental, Ensaio Randomizado.

RESUMO

Abstract Objective The aim of this study was to evaluate the best timing and feasibility of intrathecal application of sodium monosialoganglioside (GM1) after spinal cord contusion in Wistar rats as an experimental model. Methods Forty Wistar rats were submitted to contusion spinal cord injury after laminectomy. The animals were randomized and divided into four groups: Group 1 - Intrathecal application of GM1 24 hours after contusion; Group 2 - Intrathecal application of GM1 48 hours after contusion; Group 3 - intrathecal application of GM1 72 hours after contusion; Group 4 - Sham, with laminectomy and intrathecal application of 0.5 mL of 0.9% saline solution, without contusion. The recovery of locomotor function was evaluated at seven different moments by the Basso, Beattie, and Bresnahan (BBB) test. They were also assessed by the horizontal ladder, with sensory-motor behavioral assessment criteria, pre-and postoperatively. Results This experimental study showed better functional scores in the group submitted to the application of GM1, with statistically significant results, showing a mean increase when evaluated on known motor tests like the horizontal ladder and BBB, at all times of evaluation (p < 0.05), especially in group 2 (48 hours after spinal cord injury). Also, fewer mistakes and slips over the horizontal ladder were observed, and many points were achieved at the BBB scale analysis. Conclusion The study demonstrated that the intrathecal application of GM1 after spinal cord contusion in Wistar rats is feasible. The application 48 hours after the injury presented the best functional results.

RESUMO

Many experimental models exist to better understand the necrosis of the femoral head etiology, both in terms of the species variety in which necrosis is induced and in the operative techniques used for treatment. Objective: This study has two main objectives, the first is to review the literature concerning experimental models of avascular necrosis of the growing femoral head, the second, to demonstrate the experimental pig model's reproducibility using a pilot study. Methods: This was a bibliographic review to describe the attempts over time to find the best species and technique for induction that would reproduce ischemic necrosis of the growing femoral head in humans. Simultaneously, a pilot study was performed to verify the replication of induction in pigs, the species that has more similarities with the human hip. The pilot's methodological analysis consists of conventional radiology and verification of possible anatomical, pathological changes. Results: In imaging exams; lateral sub-dislocation of the femur head and triangular appearance of the head were observed, characterizing its flattening; in macroscopic examination, the femoral head flattening with femoral neck widening and shortening was identified; in histology, the proliferation of articular cartilage with the presence of vascular granulation regenerative tissue, with osteoclasts and fibrocartilaginous tissue in the metaphyseal femoral neck region was identified. Conclusion: The experimental pig model can be used as a valuable tool for the reproducibility of anatomical, pathological changes in ischemic necrosis of the growing femoral head. The model is reproducible and feasible and can be beneficial for future studies on the anatomical pathology of necrosis of the growing femoral head. Level of Evidence III, Literature Review .

Na tentativa de compreender melhor a etiologia da necrose da cabeça femoral, existe uma diversidade de modelos experimentais tanto no que diz respeito à variedade das espécies em que é induzida a necrose quanto nas técnicas operatórias utilizadas para o tratamento. Objetivo: Este trabalho tem fundamentalmente dois objetivos: a revisão da literatura concernente aos modelos experimentais da necrose avascular da cabeça do fêmur em crescimento e demonstrar a reprodutibilidade do modelo experimental do suíno por meio de um estudo piloto. Métodos: Foi realizada uma revisão bibliográfica descrevendo as tentativas ao longo do tempo em buscar qual seria a melhor espécie e técnica para indução que reproduzisse a necrose isquêmica da cabeça do fêmur em crescimento nos humanos. Simultaneamente foi feito um estudo piloto para verificar a replicação da indução na espécie suína, o espécime cujo quadril tem mais similaridades com o humano. A análise metodológica do piloto consiste na radiologia convencional e verificação das possíveis alterações anátomo patológicas. Resultados: Nos exames por imagem, foram observadas sub-luxação lateral da cabeça do fêmur e aparência triangular da cabeça, caracterizando o achatamento da mesma; no exame macroscópico, identificamos o achatamento da cabeça femoral com alargamento e encurtamento do colo; na histologia, identificamos a proliferação da cartilagem articular com presença de tecido regenerativo vascular de granulação, com osteoclastos e tecido fibrocartilaginoso na região metafisária do colo femoral. Conclusão: Podemos inferir que o modelo experimental suíno pode servir como ferramenta valiosa para a reprodutibilidade das alterações anátomo patológicas da necrose isquêmica da cabeça femoral em crescimento. O modelo é reprodutível e factível, servindo para estudos futuros sobre a anátomo patologia da necrose da cabeça do fêmur em crescimento. Nível de Evidência III, Revisão da Literatura .

RESUMO

Objective: To evaluate histological changes in peripheral nerves of rats after sciatic nerve neurorrhaphy, according to the time of exposure to hyperbaric oxygen chamber treatment. Methods: Twenty-five Wistar rats were divided into 5 groups according to the amount of exposure to hyperbaric oxygen chamber treatment. Group 1 was the control and there was no use of hyperbaric oxygen chamber; group 2 received one week of therapy; group 3, two weeks; group 4, three weeks; and group 5, four weeks. After the fourth postoperative week, the animals were submitted to euthanasia and a sciatic nerve sample sent for histological analysis. Axons proximal and distal to the neurorrhaphy were counted with axonal regeneration index measurement. Results: We observed that the number of axons distal to neurorrhaphy increases with the amount of hyperbaric oxygen chamber exposure, the results were more expressive from the third week of treatment. However, the statistical analysis found no significant difference between the groups. Conclusion: The descriptive analysis suggests benefit of using hyperbaric oxygen chamber directly proportional to the time of therapy. The study, however, did not present statistically relevant results, probably due to the reduced sample size. Subsequent studies with more significant sampling would be of great value. Level of Evidence II, Prospective Comparative Study.

Objetivo: Avaliar as alterações histológicas nos nervos periféricos após neurorrafia do nervo ciático de ratos, de acordo com o tempo de exposição ao tratamento com câmara hiperbárica de oxigênio. Métodos: Vinte e cinco ratos da raça Wistar foram divididos em cinco grupos conforme o tempo de exposição ao tratamento com câmara hiperbárica de oxigênio. O grupo 1 não recebeu o tratamento; o grupo 2 recebeu uma semana de terapia; o grupo 3, duas semanas; o grupo 4, três semanas; e o grupo 5, quatro semanas. Após quatro semanas de pós-operatório, os animais foram submetidos à eutanásia e uma amostra do nervo ciático foi enviada para análise histológica. Foram feitas contagens do número de axônios proximalmente e distalmente à neurorrafia, com medição do índice de regeneração axonal. Resultados: Observamos que o aumento do número de axônios distais à neurorrafia foi diretamente proporcional ao tempo de exposição à câmara hiperbárica de oxigênio, sendo mais expressivo a partir da terceira semana de tratamento. Entretanto, a análise estatística não encontrou diferença significativa entre os grupos. Conclusão: A análise descritiva sugere benefício do uso da câmara hiperbárica de oxigênio. Porém, devido à amostra reduzida, o estudo não apresentou resultados estatisticamente relevantes, sendo necessária a realização de estudos subsequentes com amostragem mais significativa. Nível de Evidência II, Estudo Prospectivo Comparativo.

RESUMO

ABSTRACT Many experimental models exist to better understand the necrosis of the femoral head etiology, both in terms of the species variety in which necrosis is induced and in the operative techniques used for treatment. Objective: This study has two main objectives, the first is to review the literature concerning experimental models of avascular necrosis of the growing femoral head, the second, to demonstrate the experimental pig model's reproducibility using a pilot study. Methods: This was a bibliographic review to describe the attempts over time to find the best species and technique for induction that would reproduce ischemic necrosis of the growing femoral head in humans. Simultaneously, a pilot study was performed to verify the replication of induction in pigs, the species that has more similarities with the human hip. The pilot's methodological analysis consists of conventional radiology and verification of possible anatomical, pathological changes. Results: In imaging exams; lateral sub-dislocation of the femur head and triangular appearance of the head were observed, characterizing its flattening; in macroscopic examination, the femoral head flattening with femoral neck widening and shortening was identified; in histology, the proliferation of articular cartilage with the presence of vascular granulation regenerative tissue, with osteoclasts and fibrocartilaginous tissue in the metaphyseal femoral neck region was identified. Conclusion: The experimental pig model can be used as a valuable tool for the reproducibility of anatomical, pathological changes in ischemic necrosis of the growing femoral head. The model is reproducible and feasible and can be beneficial for future studies on the anatomical pathology of necrosis of the growing femoral head. Level of Evidence III, Literature Review .

RESUMO Na tentativa de compreender melhor a etiologia da necrose da cabeça femoral, existe uma diversidade de modelos experimentais tanto no que diz respeito à variedade das espécies em que é induzida a necrose quanto nas técnicas operatórias utilizadas para o tratamento. Objetivo: Este trabalho tem fundamentalmente dois objetivos: a revisão da literatura concernente aos modelos experimentais da necrose avascular da cabeça do fêmur em crescimento e demonstrar a reprodutibilidade do modelo experimental do suíno por meio de um estudo piloto. Métodos: Foi realizada uma revisão bibliográfica descrevendo as tentativas ao longo do tempo em buscar qual seria a melhor espécie e técnica para indução que reproduzisse a necrose isquêmica da cabeça do fêmur em crescimento nos humanos. Simultaneamente foi feito um estudo piloto para verificar a replicação da indução na espécie suína, o espécime cujo quadril tem mais similaridades com o humano. A análise metodológica do piloto consiste na radiologia convencional e verificação das possíveis alterações anátomo patológicas. Resultados: Nos exames por imagem, foram observadas sub-luxação lateral da cabeça do fêmur e aparência triangular da cabeça, caracterizando o achatamento da mesma; no exame macroscópico, identificamos o achatamento da cabeça femoral com alargamento e encurtamento do colo; na histologia, identificamos a proliferação da cartilagem articular com presença de tecido regenerativo vascular de granulação, com osteoclastos e tecido fibrocartilaginoso na região metafisária do colo femoral. Conclusão: Podemos inferir que o modelo experimental suíno pode servir como ferramenta valiosa para a reprodutibilidade das alterações anátomo patológicas da necrose isquêmica da cabeça femoral em crescimento. O modelo é reprodutível e factível, servindo para estudos futuros sobre a anátomo patologia da necrose da cabeça do fêmur em crescimento. Nível de Evidência III, Revisão da Literatura .

RESUMO

ABSTRACT Objective: To evaluate histological changes in peripheral nerves of rats after sciatic nerve neurorrhaphy, according to the time of exposure to hyperbaric oxygen chamber treatment. Methods: Twenty-five Wistar rats were divided into 5 groups according to the amount of exposure to hyperbaric oxygen chamber treatment. Group 1 was the control and there was no use of hyperbaric oxygen chamber; group 2 received one week of therapy; group 3, two weeks; group 4, three weeks; and group 5, four weeks. After the fourth postoperative week, the animals were submitted to euthanasia and a sciatic nerve sample sent for histological analysis. Axons proximal and distal to the neurorrhaphy were counted with axonal regeneration index measurement. Results: We observed that the number of axons distal to neurorrhaphy increases with the amount of hyperbaric oxygen chamber exposure, the results were more expressive from the third week of treatment. However, the statistical analysis found no significant difference between the groups. Conclusion: The descriptive analysis suggests benefit of using hyperbaric oxygen chamber directly proportional to the time of therapy. The study, however, did not present statistically relevant results, probably due to the reduced sample size. Subsequent studies with more significant sampling would be of great value. Level of Evidence II, Prospective Comparative Study.

RESUMO Objetivo: Avaliar as alterações histológicas nos nervos periféricos após neurorrafia do nervo ciático de ratos, de acordo com o tempo de exposição ao tratamento com câmara hiperbárica de oxigênio. Métodos: Vinte e cinco ratos da raça Wistar foram divididos em cinco grupos conforme o tempo de exposição ao tratamento com câmara hiperbárica de oxigênio. O grupo 1 não recebeu o tratamento; o grupo 2 recebeu uma semana de terapia; o grupo 3, duas semanas; o grupo 4, três semanas; e o grupo 5, quatro semanas. Após quatro semanas de pós-operatório, os animais foram submetidos à eutanásia e uma amostra do nervo ciático foi enviada para análise histológica. Foram feitas contagens do número de axônios proximalmente e distalmente à neurorrafia, com medição do índice de regeneração axonal. Resultados: Observamos que o aumento do número de axônios distais à neurorrafia foi diretamente proporcional ao tempo de exposição à câmara hiperbárica de oxigênio, sendo mais expressivo a partir da terceira semana de tratamento. Entretanto, a análise estatística não encontrou diferença significativa entre os grupos. Conclusão: A análise descritiva sugere benefício do uso da câmara hiperbárica de oxigênio. Porém, devido à amostra reduzida, o estudo não apresentou resultados estatisticamente relevantes, sendo necessária a realização de estudos subsequentes com amostragem mais significativa. Nível de Evidência II, Estudo Prospectivo Comparativo.

RESUMO

ABSTRACT Objectives: To evaluate the functional and immunohistochemical effects of ganglioside GM1 and erythropoietin following experimental spinal cord injury. Methods: Thirty-two male BALB/c mice were subjected to experimental spinal cord injury using the NYU Impactor device and were randomly divided into the following groups: GM1 group, receiving standard ganglioside GM1 (30 mg/kg); erythropoietin group, receiving erythropoietin (1000 IU/kg); combination group, receiving both drugs; and control group, receiving saline (0.9%). Animals were evaluated according to the Basso Mouse Scale (BMS) and Hindlimb Mouse Function Score (MFS). After euthanasia, the immunohistochemistry of the medullary tissue of mice was analyzed. All animals received intraperitoneal treatment. Results: The GM1 group had higher BMS and MFS scores at the end of the experiment when compared to all other groups. The combination group had higher BMS and MFS scores than the erythropoietin and control groups. The erythropoietin group had higher BMS and MFS scores than the control group. Immunohistochemical tissue analysis showed a significant difference among groups. There was a significant increase in myelinated axons and in the myelinated axon length in the erythropoietin group when compared to the other intervention groups (p < 0.01). Conclusion: Erythropoietin and GM1 have therapeutic effects on axonal regeneration in mice subjected to experimental spinal cord injury, and administration of GM1 alone had the highest scores on the BMS and MFS scales.

RESUMO

OBJECTIVES: This study proposed a structured microsurgical training program and evaluated it with the assistance of a large sample of surgeons. METHODS: The practical course comprised 16 sessions of approximately 4 hours each. This included two sessions for suturing rubber gloves and two sessions for suturing arteries, veins, and nerves in chicken thighs. The other sessions were performed on the femoral vessels of rats: 5 sessions for end-to-end arterial anastomosis, 5 for end-to-end venous anastomosis, 1 for arterial grafting, and 1 for end-to-side anastomosis. We conducted a structured assessment of the microsurgical skills in each training session. RESULTS: In this study, 89 surgeons were evaluated. The mean scores for the different procedures were as follows: glove suturing, 33.3±0.59; chicken nerve end-to-end anastomosis, 40.3±0.49; chicken artery suturing, 40.9±0.36; chicken vein suturing, 42.3±0.36; graft interposition, 44.8±0.7; and end-to-side anastomosis, 43.7±0.63 (p<0.05 for all). The chicken thigh suturing scores were significantly higher than the rubber gloves suturing scores (p<0.01). There were no differences between scores of the rat artery and chicken thigh suturing procedures (p=0.24). The rat venous anastomosis scores were higher than the rat arterial anastomosis scores (p=0.02), as were graft interposition scores when compared with end-to-end venous anastomosis scores. The end-to-side anastomosis scores did not differ significantly from the grafting scores (p=0.85). The most common errors were inadequate knotting technique and suture rupture due to inadequate technique (both n=88 [98.9%]). CONCLUSION: We propose a 16-step, progressive microsurgical training program to learn the basic microsurgical techniques comprehensively and reliably. The program was evaluated in a large sample of trainees, and it demonstrated the adequacy of the training sequence and results.

Assuntos

RESUMO

OBJECTIVES: This study proposed a structured microsurgical training program and evaluated it with the assistance of a large sample of surgeons. METHODS: The practical course comprised 16 sessions of approximately 4 hours each. This included two sessions for suturing rubber gloves and two sessions for suturing arteries, veins, and nerves in chicken thighs. The other sessions were performed on the femoral vessels of rats: 5 sessions for end-to-end arterial anastomosis, 5 for end-to-end venous anastomosis, 1 for arterial grafting, and 1 for end-to-side anastomosis. We conducted a structured assessment of the microsurgical skills in each training session. RESULTS: In this study, 89 surgeons were evaluated. The mean scores for the different procedures were as follows: glove suturing, 33.3±0.59; chicken nerve end-to-end anastomosis, 40.3±0.49; chicken artery suturing, 40.9±0.36; chicken vein suturing, 42.3±0.36; graft interposition, 44.8±0.7; and end-to-side anastomosis, 43.7±0.63 (p<0.05 for all). The chicken thigh suturing scores were significantly higher than the rubber gloves suturing scores (p<0.01). There were no differences between scores of the rat artery and chicken thigh suturing procedures (p=0.24). The rat venous anastomosis scores were higher than the rat arterial anastomosis scores (p=0.02), as were graft interposition scores when compared with end-to-end venous anastomosis scores. The end-to-side anastomosis scores did not differ significantly from the grafting scores (p=0.85). The most common errors were inadequate knotting technique and suture rupture due to inadequate technique (both n=88 [98.9%]). CONCLUSION: We propose a 16-step, progressive microsurgical training program to learn the basic microsurgical techniques comprehensively and reliably. The program was evaluated in a large sample of trainees, and it demonstrated the adequacy of the training sequence and results.

Assuntos