The primary objective of this biomechanical study was to investigate the effect of decompressive surgery, specifically dorsal laminectomy and discectomy, on the stability of the lumbosacral joint in the dog. Different size laminectomies were compared with respect to their effect on lumbosacral stability. A total of eighteen lumbosacral motion units were collected from cadavers and divided into three groups. Group 1 was a control group and received no modification, Group 2 specimens received mini-dorsal laminectomies and discectomies (lamina of L7 caudal to the dorsal spinous process excised, lamina of S1 not affected) while Group 3 specimens received standard dorsal laminectomies and discectomies (75% of L7 lamina and 50% of S1 lamina excised). All specimens were potted in aluminium tubing and mounted in a four-point bending jig and tested in a load cell. Specimens were stressed to 21° in dorsiflexion and ventroflexion. The relevant surgical modification was then performed and the specimens re-tested to 21° in dorsiflexion and ventroflexion. All specimens were then tested to failure in ventroflexion. Force and angular displacement was recorded and used to obtain load-deformation curves for each specimen (5 curves for each specimen). From the load-deformation curves the stiffness (gradient of the graph) was determined at three set angles of deflection. These points were 6°-8°, 12°-16° and 18°-20°. The percentage change in stiffness for each specimen in both dorsiflexion and ventroflexion was obtained. Peak force at failure and angular deformation at failure were obtained when tested to failure in ventroflexion. When examining the overall stiffness of the specimen (dorsiflexion and ventroflexion and all angles of deflection) mini-dorsal laminectomy was shown to result in a 48.3% reduction in stiffness (P < 0.001) while standard dorsal laminectomy and discectomy resulted in a 59.8% reduction in stiffness (P < 0.001). These results were statistically significant. The difference between the two different types of laminectomies could be described as approaching significance (P=0.066). Larger group size would be required to determine whether this is in fact statistically significant Dorsal laminectomy combined with discectomy does have an effect on the stability of the lumbosacral joint. This may contribute to the relatively high recurrence rate following surgical treatment of degenerative lumbosacral stenosis especially in large breed highly active dogs. The study provides further support for decompressive surgery combined with a stabilisation technique when treating degenerative lumbosacral stenosis. It also provides potential support for the use of mini-dorsal laminectomies. / Dissertation (MMedVet)--University of Pretoria, 2009. / Companion Animal Clinical Studies / unrestricted

As dores lombares acometem a maioria dos atletas, inclusive os equinos. Somente o exame clínico não é suficiente para identificar a localização exata do foco doloroso. O diagnóstico definitivo só é atingido através da utilização dos meios diagnósticos complementares, neste caso, a ultrassonografia. Caso sejam constatadas anomalias discal lombossacras e/ou artropatias ITLS e/ou SI, o veterinário ainda não é capaz de quantificar a influência destas sobre o desempenho atlético do cavalo de esporte. Face a esta dúvida, objetivou-se estabelecer uma relação entre os achados dos exames físicos e ultrassonográficos, executados em 200 cavalos atletas, de quatro raças diferentes (Trote Francês, Quarto de Milha, Puro Sangue Inglês e Cavalos de Sela Francesa e Brasileiro de Hipismo). Todos os animais estavam em treinamento, participando de provas, e não apresentavam claudicação. Após exame físico, os animais foram avaliados ultrassonograficamente, por via transretal, para visualização do aspecto ventral do disco LS (L6-S1), das articulações intertransversas (ITLS) e sacroilíacas (SI), direitas e esquerdas. Para a avaliação transretal os animais foram colocados em tronco de contenção, não tendo sido observada necessidade de sedação ou emprego de outros métodos físicos. Ato contínuo foi introduzido um transdutor linear de 5-7,5 MHz e imagens do disco lombossacro, das articulações intertransversas lombossacras e sacroilíacas foram obtidas. A determinação do número de animais que apresentavam alterações durante os exames de inspeção, palpação, mobilização e avaliação dinâmica assim como a caracterização dos tipos de anomalias discais (T1, T2, T3 e T4) e artropatias ITLS e SI, sugere que durante a execução do exame físico, cavalos que não apresentem sinais clínicos não devem ser descartados de possuírem algum tipo de anomalia discal lombossacra e/ou atropatias ITLS e/ou SI. Observou-se também que as artropatias SI podem afetar o desempenho dos cavalos de trote atrelado, já para as artropatias ITLS e anomalias LS não houve significância quanto às suas influências aos achados no desempenho. / Back pain affects most athletes, including horses. The clinical examination alone is not sufficient to identify the exact location of the painful focus. The definitive diagnosis is only achieved by using complementary diagnostic tools, in the case of this study the ultrasonography. Lumbosacral anomalies and intertransverse lumbosacral and sacroiliac arthropathies, if detected ultrasonographicaly, do not directly input in loss of performance or locomotor impairment. In order to assess this issue, this study aimed to establish a relationship between the findings of physical and ultrasound examinations, performed on 200 horses athletes, from 4 different breeds, French Trotters, Quarter Horse, Thoroughbred Horses and Show Jumpers. After physical examination, the animals were evaluated by a transrectal approach with ultrasonography and the images collected were, ventral aspect of the disc LS (L6-S1), intertransverse joints (ITLS) and sacroiliac (SI), right and left. To perform this evaluation, the animals were placed in the containment trunk with any sedation methods. Immediately thereafter introduced a 5 - 7.5 MHz linear transducer, images of lumbosacral, intertransverse lombossacral and sacroiliac joints were obtained. The determination of number of animals showing abnormalities during clinical examination of inspection, palpation, mobilization and dynamic examination as well as the characterization of the types of disc anomalies (T1, T2, T3 and T4) and arthropathies ITLS and SI, enabled the realization of the following framework, where even the patient, during the execution of the clinical examination, will not provide a positive signals for certain tests, this does not rule out the possibility it has some kind of anomaly in LS joint and/or arthropathy ITLS and/or SI. It was also observed that the arthropathy of SI can affect the performance of French Trotters, and anomalies of ITLS and LS have no significance or influence on athletic performance.

As dores lombares acometem a maioria dos atletas, inclusive os equinos. Somente o exame clínico não é suficiente para identificar a localização exata do foco doloroso. O diagnóstico definitivo só é atingido através da utilização dos meios diagnósticos complementares, neste caso, a ultrassonografia. Caso sejam constatadas anomalias discal lombossacras e/ou artropatias ITLS e/ou SI, o veterinário ainda não é capaz de quantificar a influência destas sobre o desempenho atlético do cavalo de esporte. Face a esta dúvida, objetivou-se estabelecer uma relação entre os achados dos exames físicos e ultrassonográficos, executados em 200 cavalos atletas, de quatro raças diferentes (Trote Francês, Quarto de Milha, Puro Sangue Inglês e Cavalos de Sela Francesa e Brasileiro de Hipismo). Todos os animais estavam em treinamento, participando de provas, e não apresentavam claudicação. Após exame físico, os animais foram avaliados ultrassonograficamente, por via transretal, para visualização do aspecto ventral do disco LS (L6-S1), das articulações intertransversas (ITLS) e sacroilíacas (SI), direitas e esquerdas. Para a avaliação transretal os animais foram colocados em tronco de contenção, não tendo sido observada necessidade de sedação ou emprego de outros métodos físicos. Ato contínuo foi introduzido um transdutor linear de 5-7,5 MHz e imagens do disco lombossacro, das articulações intertransversas lombossacras e sacroilíacas foram obtidas. A determinação do número de animais que apresentavam alterações durante os exames de inspeção, palpação, mobilização e avaliação dinâmica assim como a caracterização dos tipos de anomalias discais (T1, T2, T3 e T4) e artropatias ITLS e SI, sugere que durante a execução do exame físico, cavalos que não apresentem sinais clínicos não devem ser descartados de possuírem algum tipo de anomalia discal lombossacra e/ou atropatias ITLS e/ou SI. Observou-se também que as artropatias SI podem afetar o desempenho dos cavalos de trote atrelado, já para as artropatias ITLS e anomalias LS não houve significância quanto às suas influências aos achados no desempenho. / Back pain affects most athletes, including horses. The clinical examination alone is not sufficient to identify the exact location of the painful focus. The definitive diagnosis is only achieved by using complementary diagnostic tools, in the case of this study the ultrasonography. Lumbosacral anomalies and intertransverse lumbosacral and sacroiliac arthropathies, if detected ultrasonographicaly, do not directly input in loss of performance or locomotor impairment. In order to assess this issue, this study aimed to establish a relationship between the findings of physical and ultrasound examinations, performed on 200 horses athletes, from 4 different breeds, French Trotters, Quarter Horse, Thoroughbred Horses and Show Jumpers. After physical examination, the animals were evaluated by a transrectal approach with ultrasonography and the images collected were, ventral aspect of the disc LS (L6-S1), intertransverse joints (ITLS) and sacroiliac (SI), right and left. To perform this evaluation, the animals were placed in the containment trunk with any sedation methods. Immediately thereafter introduced a 5 - 7.5 MHz linear transducer, images of lumbosacral, intertransverse lombossacral and sacroiliac joints were obtained. The determination of number of animals showing abnormalities during clinical examination of inspection, palpation, mobilization and dynamic examination as well as the characterization of the types of disc anomalies (T1, T2, T3 and T4) and arthropathies ITLS and SI, enabled the realization of the following framework, where even the patient, during the execution of the clinical examination, will not provide a positive signals for certain tests, this does not rule out the possibility it has some kind of anomaly in LS joint and/or arthropathy ITLS and/or SI. It was also observed that the arthropathy of SI can affect the performance of French Trotters, and anomalies of ITLS and LS have no significance or influence on athletic performance.