In August 1993, in the USA, an FDA advisory committee of experts reviewed the scientific data on pedicle screws and decided that not enough was known about the shortterm problems or the long-term safety and effectiveness of these devices to allow their use to be approved. Manufacturers were therefore forbidden to promote the use of screws in the spine, and patients were warned that pedicle scre...

STUDY DESIGN Biomechanical and histologic analysis. OBJECTIVE To compare the strength of the bone-screw interface of standard uncoated pedicle screws with screws treated with hydroxyapatite (HA), titanium plasma spray (TPS), and a composite HA-TPS coating. SUMMARY OF BACKGROUND DATA Transpedicular screw fixation has become the gold standard in the treatment of various thoracolumbar spinal c...

BACKGROUND Pedicle screw instrumentation is widely used for spinal stabilization. However, the accuracy for free-hand screw placement ranges from 69% to 94%. This study assesses the value of the existing classification systems, and investigates their impact on the ability to assess the accuracy of free-hand screw placement. METHODS Data were collected retrospectively from the medical records ...

Introduction The etiology of occipitocervical instability is vast and includes trauma, rheumatoid arthritis, infection, tumor, congenital deformity, and degenerative processes. The development of instability in this region can result in intractable pain with or without neurological deficit and requires surgical treatment. Surgical management has evolved during the past decades, and currently, i...

In the internet, a worm is usually propagated in a random multi-hop contact manner. However, the attacker will not likely select this random multi-hop propagation approach in a mobile sensor network. This is because multi-hop worm route paths to random vulnerable targets can be often breached due to node mobility, leading to failure of fast worm spread under this strategy. Therefore, an appropr...

With increasing speed, virulence, and sophistication, self-propagating worms continue to pose a serious threat to the safety of the Internet. To effectively identify and defend against self-propagating worms, a critical task is to characterize a worm along multiple dimensions. Content-based fingerprinting is a well-established dimension for worm characterization by deriving the most representat...

The paper proposes a method for identifying the front profile of worm-type active element, consisting three-screw compressor. purpose this identification is to study frontal enwrapping between profiles driver and driven in order produce possible replacement element. As it well known, two are mutually profiles, which means that problem can be treated as plane problem. was performed by specific r...

With increasing speed, virulence, and sophistication, self-propagating worms continue to pose a serious threat to the safety of the Internet. To effectively identify and defend against self-propagating worms, a critical task is to characterize a worm along multiple dimensions. Content-based fingerprinting is a well-established dimension for worm characterization by deriving the most representat...