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PURPOSE: The purpose of this study was to determine whether ankle brace use in university-level varsity volleyball athletes affected their 3-step spike jump height and whether certain types of ankle braces have a greater effect on jump height. METHODS: Nine male university-level varsity volleyball athletes participated in a repeated-measures design study in which each athlete performed three 3-step volleyball spike jumps in 3 ankle brace conditions (soft, rigid, and no brace). Vertical jump height was measured by the Vertec device and video motion analysis at a university biomechanics research laboratory. RESULTS: Vertical jump heights were significantly lower in both brace conditions (soft, 2.3 cm, standard deviation [SD] 1.2 cm, P < .001; rigid, 1.7 cm, SD 0.9 cm, P < .003) compared with the no-brace condition, and no differences in vertical jump height were observed between the brace conditions (0.6 cm, SD 0.3, P = .3). There was a negative correlation between body fat percentage and vertical jump height (r = -0.075, P = .02). The Vertec device reliably measured vertical jump in all 3 conditions. The no-brace vertical ground reaction forces during the loading phase were significantly greater than brace conditions. Ankle range of motion was greatest in the no-brace condition. CONCLUSIONS: Results from this study suggests that high-performance athletes wearing ankle braces experience a significant decrease in vertical jump height independent of the type of ankle brace worn. CLINICAL RELEVANCE: Sports physicians and health care providers caring for high-level athletes should counsel athletes on the trade-offs of wearing protective equipment in sport, as potential decreases in sports performance can lead to increased injury prevention. LEVEL OF EVIDENCE: III.
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PURPOSE: Spinal needle injections are widely applied to alleviate back pain and for anesthesia. Current treatment is performed either blindly with palpation or using fluoroscopy or computed tomography (CT). Both fluoroscopy and CT guidance expose patients to ionizing radiation. Ultrasound (US) guidance for spinal needle procedures is becoming more prevalent as an alternative. It is challenging to use US as the sole imaging modality for intraoperative guidance of spine needle injections due to the acoustic shadows created by the bony structures of the vertebra that limit visibility of the target areas for injection. We propose registration of CT and the US images to augment anatomical visualization for the clinician during spinal interventions guided by US. METHODS: The proposed method involves automatic global and multi-vertebrae registration to find the closest alignment between CT and US data. This is performed by maximizing the similarity between the two modalities using voxel intensity information as well as features extracted from the input volumes. In our method, the lumbar spine is first globally aligned between the CT and US data using intensity-based registration followed by point-based registration. To account for possible curvature change of the spine between the CT and US volumes, a multi-vertebrae registration step is also performed. Springs are used to constrain the movement of the individually transformed vertebrae to ensure the optimal alignment is a pose of the lumbar spine that is physically possible. RESULTS: Evaluation of the algorithm is performed on 10 clinical patient datasets. The registration approach was able to align CT and US datasets from initial misalignments of up to 25 mm, with a mean TRE of 1.37 mm. These results suggest that the proposed approach has the potential to offer a sufficiently accurate registration between clinical CT and US data.
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Vértebras Lumbares/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Ultrasonografía/métodos , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Diseño de Equipo , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Inyecciones Espinales , Masculino , Persona de Mediana Edad , Modelos Estadísticos , Imagen Multimodal/métodos , Agujas , Radiación Ionizante , Reproducibilidad de los Resultados , Tomografía Computarizada por Rayos X/instrumentación , Ultrasonografía/instrumentaciónRESUMEN
BACKGROUND: Surgical displays do not show uncertainty information with respect to the position and orientation of instruments. Data is presented as though it were perfect; surgeons unaware of this uncertainty could make critical navigational mistakes. METHODS: The propagation of uncertainty to the tip of a surgical instrument is described and a novel uncertainty visualization method is proposed. An extensive study with surgeons has examined the effect of uncertainty visualization on surgical performance with pedicle screw insertion, a procedure highly sensitive to uncertain data. RESULTS: It is shown that surgical performance (time to insert screw, degree of breach of pedicle, and rotation error) is not impeded by the additional cognitive burden imposed by uncertainty visualization. CONCLUSIONS: Uncertainty can be computed in real time and visualized without adversely affecting surgical performance, and the best method of uncertainty visualization may depend upon the type of navigation display.
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Cirugía Asistida por Computador/instrumentación , Cirugía Asistida por Computador/métodos , Análisis de Varianza , Tornillos Óseos , Computadores , Diseño de Equipo , Humanos , Imagenología Tridimensional , Modelos Anatómicos , Distribución Aleatoria , Reproducibilidad de los Resultados , Tomografía Computarizada por Rayos X/métodos , Resultado del Tratamiento , Incertidumbre , Interfaz Usuario-ComputadorRESUMEN
MOTIVATION: Spinal needle injections are technically demanding procedures. The use of ultrasound image guidance without prior CT and MR imagery promises to improve the efficacy and safety of these procedures in an affordable manner. METHODOLOGY: We propose to create a statistical shape model of the lumbar spine and warp this atlas to patient-specific ultrasound images during the needle placement procedure. From CT image volumes of 35 patients, statistical shape model of the L3 vertebra is built, including mean shape and main modes of variation. This shape model is registered to the ultrasound data by simultaneously optimizing the parameters of the model and its relative pose. Ground-truth data was established by printing 3D anatomical models of 3 patients using a rapid prototyping. CT and ultrasound data of these models were registered using fiducial markers. RESULTS: Pairwise registration of the statistical shape model and 3D ultrasound images led to a mean target registration error of 3.4 mm, while 81% of all cases yielded clinically acceptable accuracy below the 3.5 mm threshold.
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Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Vértebras Lumbares/diagnóstico por imagen , Modelos Biológicos , Reconocimiento de Normas Patrones Automatizadas/métodos , Técnica de Sustracción , Ultrasonografía/métodos , Algoritmos , Simulación por Computador , Humanos , Aumento de la Imagen/métodos , Modelos Estadísticos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: Femoral fractures due to birth trauma are extremely rare. External cephalic version is considered a relatively safe alternative when dealing with breech presentation, but it can be associated with complications. CASE: This patient underwent elective cephalic version for breech presentation at 36 weeks of gestation. Due to concerns of fetal distress after the version, a cesarean delivery was performed. The newborn had a bruised leg at delivery, and X-ray studies confirmed a distal femoral corner fracture. CONCLUSION: This case demonstrates another risk of external cephalic version. Physicians and patients should be aware of this potential complication.