The Current Testing Protocols for Biomechanical Evaluation of Lumbar Spinal Implants in Laboratory Setting: A Review of the Literature

In vitro biomechanical investigations have become a routinely employed technique to explore new lumbar instrumentation. One of the most important advantages of such investigations is the low risk present when compared to clinical trials. However, the best use of any experimental data can be made when standard testing protocols are adopted by investigators, thus allowing comparisons among studies. Experimental variables, such as the length of the specimen, operative level, type of loading (e.g., dynamic versus quasistatic), magnitude, and rate of load applied, are among the most common variables controlled during spinal biomechanical testing. Although important efforts have been made to standardize these protocols, high variability can be found in the current literature. The aim of this investigation was to conduct a systematic review of the literature to identify the current trends in the protocols reported for the evaluation of new lumbar spinal implants under laboratory setting

Designs and Techniques That Improve the Pullout Strength of Pedicle Screws in Osteoporotic Vertebrae: Current Status

Osteoporosis is a medical condition affecting men and women of different age groups and populations. The compromised bone quality caused by this disease represents an important challenge when a surgical procedure (e.g., spinal fusion) is needed after failure of conservative treatments. Different pedicle screw designs and instrumentation techniques have been explored to enhance spinal device fixation in bone of compromised quality. These include alterations of screw thread design, optimization of pilot hole size for non-self-tapping screws, modification of the implant's trajectory, and bone cement augmentation. While the true benefits and limitations of any procedure may not be realized until they are observed in a clinical setting, axial pullout tests, due in large part to their reproducibility and ease of execution, are commonly used to estimate the device's effectiveness by quantifying the change in force required to remove the screw from the body. The objective of this investigation is to provide an overview of the different pedicle screw designs and the associated surgical techniques either currently utilized or proposed to improve pullout strength in osteoporotic patients. Mechanical comparisons as well as potential advantages and disadvantages of each consideration are provided herein

Shunt tapping versus lumbar puncture for evaluating cerebrospinal fluid infections in a pediatric population

WOS: 000460303600017PubMed ID: 30649821AIM: To compare the results of lumbar puncture (LP) and shunt tapping in pediatric patients with suspected ventriculoperitoneal shunt infection. MATERIAL and METHODS: Medical records of pediatric patients with suspected shunt infections were retrospectively analyzed. All patients had cerebrospinal fluid samples obtained either via shunt tapping, LP or both. The diagnosis of infection was made when at least one cerebrospinal fluid had positive culture results. The patients with negative cerebrospinal fluid culture results were followed up for at least 6 months to monitor the occurrence of central nervous system infection. RESULTS: There were 20 patients in the study (12 males, 8 females). Cerebrospinal fluid was obtained by shunt tapping in 11, by lumbar puncture in 9 and by both methods in one patient. Thirteen patients [ Shunt tapping: 5/11 (45%), LP: 7/9 (78%), Both: 1)] were diagnosed with shunt infection on the basis of cerebrospinal fluid culture. Seven patients with negative cerebrospinal fluid culture were found to have infections unrelated to shunts and did not show evidence of cerebrospinal fluid infection during the follow-up period. Although the percentage of detecting the infection was higher in LP group, both groups showed negative predictive value of 100%. CONCLUSION: Both shunt tapping and LP are effective in establishing the diagnosis of shunt infection in suspected patients

Bone fusion system

A method and system for performing bone fusion and/or securing one or more bones, such as adjacent vertebra, are disclosed. The screws include a threaded tip connected to a main shaft and a threaded outer sleeve that rotates relative to the outer shaft until locked down. Independent rotation of the threaded outer sleeve relative to the threaded distal tip allows compression or distraction to modify the gap between the vertebral bodies. The screws are passed from the inferior to superior vertebra or superior to inferior, for example, through a trans-pedicular route to avoid neurological compromise. At the same time, the path of screw insertion is oriented to reach superior or inferior vertebra. An intervertebral cage of the system is configured for lateral expansion from a nearly straight configuration to form a large footprint in the disc space. The screws and cage may be combined for improved fixation with minimal invasiveness

Expandable intervertebral cage

A method and system for performing bone fusion and/or securing one or more bones, such as adjacent vertebra, are disclosed

Bone fusion systen

A method and system for performing bone fusion and/or securing one or more bones, such as adjacent vertebra, are disclosed. The screws include a threaded tip connected to a main shaft and a threaded outer sleeve that rotates relative to the outer shaft until locked down. Independent rotation of the threaded outer sleeve relative to the threaded distal tip allows compression or distraction to modify the gap between the vertebral bodies. The screws are passed from the inferior to superior vertebra or superior to inferior, for example, through a transpedicular route to avoid neurological compromise. At the same time, the path of screw insertion is oriented to reach superior or inferior vertebra. An intervertebral cage of the system is configured for lateral expansion from a nearly straight configuration to form a large footprint in the disc space. The screws and cage may be combined for improved fixation with minimal invasiveness

Expandable intervertebral cage

A method and system for performing bone fusion and/or securing one or more bones, such as adjacent vertebra, are disclosed

Expandable intervertebral cage

A method and system for performing bone fusion and/or securing one or more bones, such as adjacent vertebra, are disclosed

Bone fusion system

A method and system for performing bone fusion and/or securing one or more bones, such as adjacent vertebra, are disclosed. The screws include a threaded tip connected to a main shaft and a threaded outer sleeve that rotates relative to the outer shaft until locked down. Independent rotation of the threaded outer sleeve relative to the threaded distal tip allows compression or distraction to modify the gap between the vertebral bodies. The screws are passed from the inferior to superior vertebra or superior to inferior, for example, through a trans-pedicular route to avoid neurological compromise. At the same time, the path of screw insertion is oriented to reach superior or inferior vertebra. An intervertebral cage of the system is configured for lateral expansion from a nearly straight configuration to form a large footprint in the disc space. The screws and cage may be combined for improved fixation with minimal invasiveness