(Lack of) Corticospinal facilitation in association with hand laterality judgments.

In recent years, mental practice strategies have drawn much interest in the field of rehabilitation. One form of mental practice particularly advocated involves judging the laterality of images depicting body parts. Such laterality judgments are thought to rely on implicit motor imagery via mental rotation of one own's limb. In this study, we sought to further characterize the involvement of the primary motor cortex (M1) in hand laterality judgments (HLJ) as performed in the context of an application designed for rehabilitation. To this end, we measured variations in corticospinal excitability in both hemispheres with motor evoked potentials (MEPs) while participants (n = 18, young adults) performed either HLJ or a mental counting task. A third condition (foot observation) provided additional control. We hypothesized that HLJ would lead to a selective MEP facilitation when compared to the other tasks and that this facilitation would be greater on the right than the left hemisphere. Contrary to our predictions, we found no evidence of task effects and hemispheric effects for the HLJ task. Significant task-related MEP facilitation was detected only for the mental counting task. A secondary experiment performed in a subset of participants (n = 6) to further test modulation during HLJ yielded the same results. We interpret the lack of facilitation with HLJ in the light of evidence that participants may rely on alternative strategies when asked to judge laterality when viewing depictions of body parts. The use of visual strategies notably would reduce the need to engage in mental rotation, thus reducing M1 involvement. These results have implications for applications of laterality tasks in the context of the rehabilitation program.

The influence of the rib cage on the severity of thoracic spine burst fractures / Influência da caixa torácica na gravidade da fratura da coluna torácica tipo explosão / La influencia de la caja torácica en la gravedad de la fractura por estallido en la columna torácica

ABSTRACT Objective: To analyze the anatomic influence of the ribs related to the severity of thoracic spine burst fractures. Methods: A retrospective review of 28 patients with thoracic spine burst fractures hospitalized by the Spine Group of the Hospital Ortopédico de Passo Fundo between January 2002 and December 2016 was conducted. The kyphosis, vertebral collapse, and narrowing of the vertebral canal measurements were compared between patients who had fractures at the true and false rib levels (T1 to T10) and those with fractures at the floating rib levels (T11 to T12). Results: The kyphosis, vertebral collapse, and narrowing of the vertebral canal values, measured only for vertebrae pertaining to the rib cage, were low. In addition, there were no statistically significant differences between the measurements of the group of patients with fractures at the level of the true and false ribs (T1 to T10) and the group of patients whose fractures were at the level of the floating ribs (T11 and T12). Conclusion: The differences between the traumatic structural changes in the vertebrae with true and false ribs (T1 to T10) and the vertebrae with floating ribs (T11 and T12) were not significant in the present study. Level of Evidence II; Retrospective study.

RESUMO Objetivo: Analisar a influência anatômica das costelas sobre a gravidade das fraturas da coluna torácica tipo explosão. Métodos: Foi realizada uma revisão retrospectiva de 28 pacientes com fratura tipo explosão na coluna torácica, internados no período compreendido entre janeiro de 2002 a dezembro de 2016 pelo Grupo de Coluna do Hospital Ortopédico de Passo Fundo . As mensurações de cifose, colapso vertebral e estreitamento do canal vertebral foram comparadas entre os pacientes que apresentavam fraturas no nível das costelas verdadeiras ou falsas (T1 a T10) e aqueles com fraturas no nível das costelas flutuantes (T11 a T12). Resultados: Os valores da cifose, colapso vertebral e estreitamento do canal vertebral, mensurados apenas nas vértebras pertencentes à caixa torácica, mostraram-se baixos. Além disso, as mensurações não apresentaram diferenças estatísticas significativas quando foram comparados os grupos de pacientes que apresentavam fraturas no nível das costelas verdadeiras ou falsas (T1 a T10) com aqueles cujas fraturas eram no nível das costelas flutuantes (T11 e T12). Conclusões: As diferenças entre as alterações estruturais traumáticas nas vértebras com costelas verdadeiras e falsas (T1 a T10) e as vértebras com costelas flutuantes (T11 e T12) não foram significativas no presente estudo. Nível de Evidência II; Estudo retrospectivo.

RESUMEN Objetivo: Analizar la influencia anatómica de las costillas con respecto a la gravedad de las fracturas de la columna torácica por estallido. Métodos: Se realizó una revisión retrospectiva de 28 pacientes con fractura de columna torácica por estallido, ingresados en el período comprendido entre enero de 2002 y diciembre de 2016 por el Grupo de Columna del Hospital Ortopédico de Passo Fundo. Se compararon las medidas de cifosis, colapso vertebral y estrechamiento del conducto vertebral entre los pacientes que presentaban fracturas a nivel de las costillas verdaderas o falsas (T1 a T10) y aquellos con fracturas a nivel de las costillas flotantes (T11 a T12). Resultados: Los valores de cifosis, colapso vertebral y estrechamiento del conducto vertebral, medidos solamente en las vértebras pertenecientes a la caja torácica, se mostraron bajos. Además, las mediciones no presentaron diferencias estadísticamente significativas al comparar los grupos de pacientes que presentaban fracturas a nivel de las costillas verdaderas o falsas (T1 a T10) con aquellos cuyas fracturas estaban a nivel de las costillas flotantes (T11 a T12). Conclusiones: Las diferencias entre los cambios estructurales traumáticos en las vértebras con costillas verdaderas y falsas (T1 a T10) y las vértebras con costillas flotantes (T11 y T12) no fueron significativas en el presente estudio. Nivel de Evidencia II; Estudio retrospectivo.