Trajectory Stress and Angle Values Correlation to Deep Beams Dimensional Ratio

SNI 2847-2019 defines a deep beam as a structural component that is loaded on one side and supported on the opposite face, allowing compressive components such as struts to form between the loads and supports. It is also stated that the ratio of the net span of the beam to the height of the beam must match the standards (l/h) 4. The goal of this investigation is to determine the value of the stress’s correlation and the trajectory angle to the ratio of the l/beam h's with a span of 4 meters when subjected to a point load of P = 2,000 kN. In the analysis procedure, SAP v.14 is being used to determine the value of stresses and trajectory angles of variations l/h. The results obtained from this study is ratio of l / h of deep beam affects the magnitude of the stress and the angle of the trajectory. Increasingly the width of the beam has no significant effect on the resulting trajectory angle.

REPRODUCIBILITY OF S2-ALAR ILIAC SCREW MORPHOMETRIC ANALYSIS

ABSTRACT Objective: To evaluate the reproducibility of a S2-alar iliac (S2AI) screw parameters measurement method by inter and intraobserver reliability. Methods: Cross-sectional study, considering computed tomography exams. Morphometric analysis was performed by multiplanar reconstructions. Screw length, diameter and trajectory angles were the studied variables. To analyze the measurements reproducibility, intraclass correlation coefficient (ICC) was used. Results: Interobserver reliability was classified as strong for screw shortest length (ICC: 0.742) and diameter (ICC: 0.699). Interobserver reliability was classified as moderate for screw longest length (ICC: 0.553) and for screw trajectory angles in the axial plane for the longest (ICC: 0.478) and for the shortest lengths (ICC: 0.591). Intraobserver reliability was interpreted as excellent for screw shortest (ICC: 0.932) and longest lengths (ICC: 0.962) and diameter (ICC: 0.770) and screw trajectory angles in the axial plane for the screw longest (ICC: 0.773) and shortest lengths (ICC: 0.862). There were weak interobserver and strong intraobserver reliabilities for trajectory angle in sagittal plane, but no statistical significance was found. Conclusion: Inter and intraobserver reliability of S2AI screw morphometric parameters were interpreted from moderate to excellent in almost all studied variables, except for the screw trajectory angle in the sagittal plane measurement. Level of Evidence IV, Diagnostic Studies - Investigating a Diagnostic Test.

The feasibility of anterior transpedicle screw fixation in lumbosacral spine: a radiographic and cadaveric study

Background: The anterior transpedicle screw technique for L5 and S1 is crucial for proper anterior lumbar interbody fusion. This study aimed to determine the projection, screw trajectory angle, and bone screw passageway length (BSPL) of the anterior transpedicle screw in L5 and S1, as well as the screw’s insertion regularity and the operating area that is safe for its insertion.Methods: Forty patients with low back pain, all of whom had lumbar computed tomography scans available, were included in a retrospective analysis. Radiographic parameters were measured, including the distances from the projection to the upper endplate, lower endplate, and midline; the transverse and sagittal screws’ angles; and the BSPL. Ten fresh adult cadaveric lumbosacral spine segments were chosen to determine the safe anatomical area at which to operate. Finally, anterior transpedicle screws were inserted in L5 and S1 to determine the regularity of anterior pedicle screw insertion.Results: We measured the anterior projection parameters, including the distances to the upper endplate (L5:12.5 ± 1.3 mm; S1: 4.54 ± 0.87 mm), lower endplate (L5: 17.3 ± 1.6 mm), and midline (L5: 6.6 ± 0.7 mm; S1: 6.6 ± 0.6 mm); the screw trajectory angle, including the transverse screw angle (L5: 25.3° ± 2.8°; S1: 25.7° ± 2.6°), sagittal screw angle (L5: 17.1° ± 1.7°; S1: 22.4° ± 1.1°); and the BSPL (L5: 48.6 ± 3.5 mm; S1: 48.0 ± 3.5 mm). We then identified the safe operating area and the regularity of L5 and S1 anterior pedicle screw insertions.Conclusions: We determined the projection, screw trajectory angle, and BSPL of anterior transpedicle screws in L5 and S1, their insertion regularity, and the area in which the operation could be safely performed.

Anterior transpedicle screw in lumbosacral spine and radiographic measurements: a retrospective analysis

Background The anterior transpedicle screw technique for L5 and S1 is crucial for proper anterior lumbar interbody fusion. This study aimed to determine the projection, screw trajectory angle, and bone screw passageway length (BSPL) of the anterior transpedicle screw in L5 and S1, as well as the screw’s insertion regularity and the operating area that is safe for its insertion. Methods Forty patients with low back pain, all of whom had lumbar computed tomography scans available, were included in a retrospective analysis. Radiographic parameters were measured, including the distances from the projection to the upper endplate, lower endplate, and midline; the transverse and sagittal screws’ angles; and the BSPL. Ten fresh adult cadaveric lumbosacral spine segments were chosen to determine the safe anatomical area at which to operate. Finally, anterior transpedicle screws were inserted in L5 and S1 to determine the regularity of anterior pedicle screw insertion. Results We measured the anterior projection parameters, including the distances to the upper endplate (L5:12.5 ± 1.3 mm; S1: 4.54 ± 0.87 mm), lower endplate (L5: 17.3 ± 1.6 mm), and midline (L5: 6.6 ± 0.7 mm; S1: 6.6 ± 0.6 mm); the screw trajectory angle, including the transverse screw angle (L5: 25.3° ± 2.8°; S1: 25.7° ± 2.6°), sagittal screw angle (L5: 17.1° ± 1.7°; S1: 22.4° ± 1.1°); and the BSPL (L5: 48.6 ± 3.5 mm; S1: 48.0 ± 3.5 mm). We then identified the safe operating area and the regularity of L5 and S1 anterior pedicle screw insertions. Conclusions We determined the projection, screw trajectory angle, and BSPL of anterior transpedicle screws in L5 and S1, their insertion regularity, and the area in which the operation could be safely performed.

Establishing a New Bony Landmark for Safe Screw Insertion in Medial Displacement Calcaneal Osteotomy: A Simulation-Based Approach

Category: Hindfoot; Other Introduction/Purpose: Medial displacement calcaneal osteotomy (MDCO) is a commonly performed procedure in flatfoot reconstruction. Fixation is often achieved with screws due to its ability to compress across the osteotomy site. Screws are placed via a free-handed technique without direct fluoroscopic visualization, due to difficulty attaining a simultaneous axial calcaneal view. In addition, the posterior calcaneal tuber translates medially after displacement, resulting in altered anatomical geometry. It is therefore important to establish a reliable external bony landmark when performing free-handed interfragmentary fixation in order to avoid potential screw-related complications and to provide better surgical technique and fixation. The purposes of this study are to validate a new external bony landmark and to establish the appropriate trajectory and screw length for free-hand screw fixation in MDCO. Methods: A total of 84 postoperative computed tomography (CT) scans of MDCO in 70 patients were analyzed. The images were reconstructed using a 3-dimensional simulation program (Vworks 4.0, Cybermed). Virtual screw insertion was simulated by aiming towards two bony landmarks: the base of the 5th metatarsal in the axial plane, and the sinus tarsi in the sagittal plane (Figure 1). A grading system was also utilized to classify scenarios in which the screw breached the distal cortical wall: Grade 1 was defined as contact between the virtual screw and the cortex, Grade 2 as the screw approaching the outer margin of the cortex, and Grade 3 as the screw penetrating the outer cortex. The trajectory angle between the screw and the osteotomy, as well as the screw size, were also measured. Results: The average age of patients was 24.5 (range, 19 to 53), and 100% were males. The average displacement of the posterior calcaneal fragment was 7.3+-1.5 mm (range, 3.9 to 13.8). Among the 84 virtual screws, only five (6.0%) breached the medial cortical wall of the osteotomized calcaneus. All medial breaches were Grade 1. None of the virtual screws breached the lateral cortical wall. Mean trajectory angle between the virtual screw and the osteotomy site was 74.9+-6.7˚ (range, 60.0 to 89.8˚). In the perioperative data, estimated maximum screw length by simulation was 55.6+-4.4 mm (range, 50 to 65). Conclusion: Our results suggest that the optimal trajectory of free-handed screw placement can be determined through simulation of calcaneal interfragmentary screw insertion using postoperative CT imaging. Using this simulation technology, we determined a trajectory towards the sinus tarsi on the sagittal plane and the base of the 5th metatarsal on the axial plane to be a reliable external bony landmark for placement of screws in MDCO. These promising results have potential implications in achieving better fixation as well as improving union rates and operative outcomes.

Anterior Transpedicle Screw in Lumbosacral Spine and Radiographic Measurements: A Retrospective Analysis

Background The anterior transpedicle screw technique for L5 and S1 is crucial for proper anterior lumbar interbody fusion. This study aimed to determine the projection, screw trajectory angle, and bone screw passageway length (BSPL) of the anterior transpedicle screw in L5 and S1, as well as the screw’s insertion regularity and the operating area that is safe for its insertion. Methods Forty patients with low back pain, all of whom had lumbar computed tomography scans available, were included in a retrospective analysis. Radiographic parameters were measured, including the distances from the projection to the upper endplate, lower endplate, and midline; the transverse and sagittal screws’ angles; and the BSPL. Ten fresh adult cadaveric lumbosacral spine segments were chosen to determine the safe anatomical area at which to operate. Finally, anterior transpedicle screws were inserted in L5 and S1 to determine the regularity of anterior pedicle screw insertion. Results We measured the anterior projection parameters, including the distances to the upper endplate (L5:12.5 ± 1.3 mm; S1: 4.54 ± 0.87 mm), lower endplate (L5: 17.3 ± 1.6 mm), and midline (L5: 6.6 ± 0.7 mm; S1: 6.6 ± 0.6 mm); the screw trajectory angle, including the transverse screw angle (L5: 25.3° ± 2.8°; S1: 25.7° ± 2.6°), sagittal screw angle (L5: 17.1° ± 1.7°; S1: 22.4° ± 1.1°); and the BSPL (L5: 48.6 ± 3.5 mm; S1: 48.0 ± 3.5 mm). We then identified the safe operating area and the regularity of L5 and S1 anterior pedicle screw insertions. Conclusions We determined the projection, screw trajectory angle, and BSPL of anterior transpedicle screws in L5 and S1, their insertion regularity, and the area in which the operation could be safely performed.

Compatibility of Passenger Vehicles and Cable Median Barrier Systems

Cross-median crashes are one of the most severe type of highway crashes. Many state Departments of Transportation (DOTs) install median barriers, such as cable median barriers (CMBs), to reduce the rate of cross-median crashes. Nonetheless, these barriers are not always successful. Approximately 20,000 cable barrier crashes throughout the United States spanning between 1999 and 2010 were examined, and detailed data was sufficient to determine the prevailing causes of 182 penetration crashes (i.e., barrier was breached). Penetration crashes involving CMBs were affected by: (1) impact conditions; (2) barrier placement and design; and (3) vehicle factors, including geometry and inertial properties. In general, CMB crashes occur at higher CG trajectory angles than with other roadside features. The 85th percentile CG trajectory angle for cable barriers was 39 degrees, compared to 25 degrees when all roadside features are considered. Approximately 2.2% of all CMB crashes were severe, although penetrations were between two and thirteen times more likely to be severe than non-penetration crashes. Vehicle factors such as weight and geometrical profile affected the likelihood of CMB penetrations. Headlights or taillights fractured or were damaged in approximately 80% of non-penetration crashes, but were damaged or fractured in less than 60% of penetration crashes, often by additional unrelated impacts. Lastly, heavier vehicles with more kinetic energy were more likely than similar, lighter vehicles to penetrate CMBs. Through better understanding of all of the complicating factors affecting CMB performance, better designs and guidelines can be prepared to maximize CMB effectiveness.

Hardware Design of Bipedal Locomotion Robot

This paper aims to design and develop a control system for the biped robot. The Peripheral Interface Controller (PIC) main controller board is designed to control the servo motor controller board which assures the biped robot to maintain its stability. This robot consists of PIC microcontroller, servo controller, servo motor, and sensors. The bracket parts are fabricated to mount the servo motors by constructing the biped structure. The PIC microcontroller provides interface among the sensors input, servo motor controller, and servo motor. The biped robot is able to walk in a stable motion under a flat plane. The sensors feedbacks enable the controller to adjust the stability of biped robot. The biped robot is able to perform walking steps and crouching action through the configuration of trajectory angle values of the servo motors.