Study Design: A biomechanical study of pedicle-screw pullout strength.
Purpose: To develop a decision tree based on pullout strength for evaluating pedicle-screw instrumentation.
Overview Of Literature: Clinically, a surgeon's understanding of the holding power of a pedicle screw is based on perioperative intuition (which is like insertion torque) while inserting the screw. This is a subjective feeling that depends on the skill and experience of the surgeon. With the advent of robotic surgery, there is an urgent need for the creation of a patient-specific surgical planning system. A learning-based predictive model is needed to understand the sensitivity of pedicle-screw holding power to various factors.
Methods: Pullout studies were carried out on rigid polyurethane foam, representing extremely osteoporotic to normal bone for different insertion depths and angles of a pedicle screw. The results of these experimental studies were used to build a pullout-strength predictor and a decision tree using a machine-learning approach.
Results: Based on analysis of variance, it was found that all the factors under study had a significant effect (p <0.05) on the holding power of a pedicle screw. Of the various machine-learning techniques, the random forest regression model performed well in predicting the pullout strength and in creating a decision tree. Performance was evaluated, and a correlation coefficient of 0.99 was obtained between the observed and predicted values. The mean and standard deviation of the normalized predicted pullout strength for the confirmation experiment using the current model was 1.01±0.04.
Conclusions: The random forest regression model was used to build a pullout-strength predictor and decision tree. The model was able to predict the holding power of a pedicle screw for any combination of density, insertion depth, and insertion angle for the chosen range. The decision-tree model can be applied in patient-specific surgical planning and a decision-support system for spine-fusion surgery.
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http://dx.doi.org/10.31616/asj.2018.12.4.611 | DOI Listing |
JBJS Essent Surg Tech
December 2024
Department of Orthopaedics and Rehabilitation, Yale School of Medicine, New Haven, Connecticut.
Background: For complete disruption of the posterolateral corner (PLC) structures, operative treatment is most commonly advocated, as nonoperative treatment has higher rates of persistent lateral laxity and posttraumatic arthritis. Some studies have shown that acute direct repair results in revision rates upwards of 37% to 40% compared with 6% to 9% for initial reconstruction. In a recent study assessing the outcomes of acute repair of PLC avulsion injuries with 2 to 7 years of follow-up, patients with adequate tissue were shown to have a much lower failure rate than previously documented.
View Article and Find Full Text PDFPLoS One
December 2024
Bio-Inspired Technology Group, Faculty of Mechanical Engineering, Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands.
Pedicle screws have long been established as the gold standard for spinal bone fixation. However, their fixation strength can be compromised in cases of low bone density, particularly in osteoporotic bone, due to the reliance on a micro-shape lock between the screw thread and the surrounding bone. To address this challenge, we propose augmenting conventional pedicles screws with a curved compliant anchor.
View Article and Find Full Text PDFHeliyon
December 2024
Department of Civil, Environmental, and Construction Engineering, Texas Tech University, USA.
This study presents the design and experimental evaluation of advanced corrosion protection coatings for application on prestressing strands which are the core constituents of prestressed concrete structures such as bridges. Variety of self-heal coatings embodying corrective and protective phenomena in response to the degrading effects of corrosion have been designed and tested in simulated aggressive weathering conditions. Standard 7-wire prestressing strands coated with self-heal epoxy, self-heal toughened epoxy and hybrid epoxy coating systems were subjected to salt fog spray up to a duration of 2500 h, and 3M CalCl, 3M NaOH, saturated Ca(OH) solutions and distilled water up to 45 days duration.
View Article and Find Full Text PDFPatient Saf Surg
December 2024
Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
Background: External ventricular drain (EVD) insertion is one of the most commonly performed neurosurgical procedures. Herein, we introduce a new concept of a cranial fixation device for insertion of EVDs, that reduces reliance on freehand placement and drilling techniques and provides a simple, minimally invasive approach that provides strong fixation to minimal thickness skulls.
Methods: An experimental device for catheter insertion and fixation was designed and tested in both ex-vivo and in-vivo conditions to assess accurate cannulation of the ventricle and to test the strength of fixation to the skull.
Materials (Basel)
November 2024
Synergetic Extreme Condition High-Pressure Science Center, State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Qianjin Street, Changchun 130012, China.
Introducing a second phase has been an effective way to solve the brittleness of boron carbide (BC) for its application. Though reduced graphene oxide (rGO) is an ideal candidate for reinforcing the BC duo's two-dimensional structure and excellent mechanical properties, the toughness is less than 6 MPa·m, or the hardness is lower than 30 GPa in BC-graphene composites. A barrier to enhancing toughness is the weak interface strength between rGO and BC, which limits the bridging and pull-out toughening effects of rGO.
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