Kyphoplasty is a therapeutic option for pain relief in the setting of compression fractures. Cement extravasation into adjacent disks is a common occurrence. The biomechanical and clinical consequences of cement in the disks currently are unknown. This study investigated the biomechanical effects of cement extravasation into the intervertebral disk in a human cadaveric model. Seven thoracolumba...

The use of the constant-deviation prism for producing monochromatic light introduces the problem of image shifts that result from rotating the prism when changing from one spectral line to another. The magnitudes of both the lateral and the axial components of this shift, for a given rotation of the prism, depend upon the position of the axis about which the prism rotates. A position for the ax...

A cause of limited physical activity levels in youth is the presence of low back pain (LBP), therefore proper assessment of low back function in physical education settings is needed to identify children who may be at risk. The purpose of this study was to determine the concurrent and criterion-referenced validity of field tests of low back and core muscular endurance in school-aged children. T...

Though asymmetric loading between the medial and lateral compartments of total knee replacements may contribute to implant loosening and failure, the in vivo contact force distribution during dynamic daily activities remains unknown. This study reports in vivo medial and lateral contact forces experienced by a well-aligned knee implant for a variety of activities. In vivo implant motion and tot...

Unlike the rest of the axial skeleton, which develops solely from somitic mesoderm, patterning of the rib cage is complicated by its derivation from two distinct tissues. The thoracic skeleton is derived from both somitic mesoderm, which forms the vertebral bodies and ribs, and from lateral plate mesoderm, which forms the sternum. By generating mouse mutants in Hox5, Hox6 and Hox9 paralogous gr...

Background The location of the ulnar styloid process can be confusing because the radius and the hand rotate around the ulna. The purpose of this study was to identify the absolute location of the ulnar styloid process, which is independent of forearm pronation or supination, to use it as a reference for neutral forearm rotation on lateral radiographs of the wrist. Methods Computed tomography...

Turbomachinery shafting and casings typically experience axial growth during thermal transients occurring at startup, shutdown, and changes of load. This growth does not usually present difficulties during operation. However, this paper discusses four recent turbomachinery trains that experienced radial subsynchronous vibration resulting from axial misalignment. In each example, the train inclu...

We assessed the reproducibility of lateral and axial measurements performed with spectral-domain optical coherence tomography (SDOCT) instruments from a single manufacturer and across several manufacturers. One human retina phantom was imaged on two instruments each from four SDOCT platforms: Zeiss Cirrus, Heidelberg Spectralis, Bioptigen SDOIS, and hand-held Bioptigen Envisu. Built-in software...

We performed a biomechanical study on human cadaver spines to determine the effect of three different interbody cage designs, with and without posterior instrumentation, on the three-dimensional flexibility of the spine. Six lumbar functional spinal units for each cage type were subjected to multidirectional flexibility testing in four different configurations: intact, with interbody cages from...