scholarly journals Two-Dimensional Visualization of the Three-Dimensional Planned Sacroiliac Screw Corridor with the Slice Fusion Method

2021 ◽  
Vol 10 (2) ◽  
pp. 184
Author(s):  
Maximilian Kerschbaum ◽  
Siegmund Lang ◽  
Florian Baumann ◽  
Volker Alt ◽  
Michael Worlicek
Keyword(s):  
Pelvic Ring ◽  
Three Dimensional ◽  
Fusion Method ◽  
Two Dimensional ◽  
Posterior Pelvic Ring ◽  
Simple Method ◽  
Sacroiliac Screw ◽  
Screw Insertion ◽  
Multiplanar Reconstructions ◽  
Screw Position

Insertion of sacro-iliac (SI) screws for stabilization of the posterior pelvic ring without intraoperative navigation or three-dimensional imaging can be challenging. The aim of this study was to develop a simple method to visualize the ideal SI screw corridor, on lateral two-dimensional images, corresponding to the lateral fluoroscopic view, used intraoperatively while screw insertion, to prevent neurovascular injury. We used multiplanar reconstructions of pre- and postoperative computed tomography scans (CT) to determine the position of the SI corridor. Then, we processed the dataset into a lateral two-dimensional slice fusion image (SFI) matching head and tip of the screw. Comparison of the preoperative SFI planning and the screw position in the postoperative SFI showed reproducible results. In conclusion, the slice fusion method is a simple technique for translation of three-dimensional planned SI screw positioning into a two-dimensional strict lateral fluoroscopic-like view.

COMPARISON OF X-RAY AND CT METHODS FOR ASSESSING SACRAL SHAPE VARIANTS AND IDENTIFYING A SECURE SACROILIAC SCREW FIXATION CORRIDOR

2019 ◽  
Vol 22 (03n04) ◽  
pp. 1950007
Author(s):  
Florian Radetzki ◽  
Felix Goehre ◽  
Stefan Schwan ◽  
Andreas Wienke ◽  
Lars Jansch ◽  
...  
Keyword(s):  
Predictive Value ◽  
Screw Fixation ◽  
Pelvic Ring ◽  
Invasive Technique ◽  
Posterior Pelvic Ring ◽  
Predictive Values ◽  
X Ray ◽  
Sacroiliac Screw ◽  
Screw Insertion ◽  
Sacroiliac Screw Fixation

Sacroiliac screw fixation is the only minimally invasive technique for stabilizing unstable posterior pelvic ring fractures. X-ray/CT methods identify sacral shape variants, which influence screw fixation feasibility at sacral segment S1. As no reliability analysis was previously published, this study analyzed four X-ray/CT-based screw corridor evaluation methods. CT datasets of 80 human pelvises (♂[Formula: see text][Formula: see text], ♀[Formula: see text][Formula: see text], [Formula: see text] years, [Formula: see text][Formula: see text]cm, [Formula: see text][Formula: see text]kg) were used. CTs were post-processed using Amira 5.2 software to generate 3D models and analyzed for S1 transverse 7.3[Formula: see text]mm screw corridors using a C++ program. CT-slices and radiograph-like images were generated per each classification’s requirements. Five surgeons independently assessed sacral shape and transverse screw insertion feasibility. Sensitivity, specificity, and positive/negative predictive values were calculated. C++ analysis indicated feasible screw insertion in 66 cases (82%). Sensitivities were 86% (Mendel), 75% (Routt), 74% (Carlson), and 67% (Kim). Specificities were 73% (Mendel) and 79% (Kim). Mean positive predictive value spanned from 54.6% (Mendel) to 26.2% (Carlson); negative predictive value spanned from 94.5% (Kim) to 90.4% (Carlson). No significant differences existed between surgeons. Mendel’s classification provides reliable and reproducible assessment via the lateral sacral triangle, without additional CTs like Carlson or Routt or the subjectivity of Kim’s method.

scholarly journals Physiological in vitro sacroiliac joint motion: a study on three‐dimensional posterior pelvic ring kinematics

2018 ◽  
Vol 234 (3) ◽  
pp. 346-358 ◽  
Author(s):  
Niels Hammer ◽  
Mario Scholze ◽  
Thomas Kibsgård ◽  
Stefan Klima ◽  
Stefan Schleifenbaum ◽  
...  
Keyword(s):  
Sacroiliac Joint ◽  
Pelvic Ring ◽  
Three Dimensional ◽  
Joint Motion ◽  
Posterior Pelvic Ring

scholarly journals Tape suture for stabilization of incomplete posterior pelvic ring fractures—biomechanical analysis of a new minimally invasive treatment for incomplete lateral compression pelvic ring fractures

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Christopher Alexander Becker ◽  
Adrian Cavalcanti Kussmaul ◽  
Eduardo Manuel Suero ◽  
Markus Regauer ◽  
Matthias Woiczinski ◽  
...  
Keyword(s):  
Pelvic Ring ◽  
Tracking System ◽  
Fracture Site ◽  
Biomechanical Analysis ◽  
Lateral Compression ◽  
Posterior Pelvic Ring ◽  
Sacroiliac Screw ◽  
Minimal Invasiveness ◽  
Compression Fractures ◽  
Pelvic Ring Fractures

Abstract Background Incomplete lateral compression fractures (including AO Type B2.1) are among the most common pelvic ring injuries. Although the treatment of choice remains controversial, sacroiliac (SI) screws are commonly used for the operative treatment of incomplete lateral compression fractures of the pelvic ring. However, the disadvantages of SI screws include the risk of nerve root or blood vessel injury. Recently, tape sutures have been found useful as stabilizing material for the treatment of injuries of the syndesmosis, the rotator cuff and knee ligaments. In this current study, we aimed to test the biomechanical feasibility of tape sutures to stabilize the pelvis in the setting of AO Type B2.1 injury. Methods Six human cadaveric pelvises underwent cyclic loading to compare the biomechanical stability of different osteosynthesis methods in a B2.1 fracture model. The methods tested in this experiment were a FiberTape® suture and the currently established SI screw. A 3D ultrasound tracking system was used to measure fracture fragment motion. Linear regression was used to model displacement and stiffness at the posterior and anterior pelvic ring. Results At the posterior fracture site, the FiberTape® demonstrated similar displacement (2.2 ± 0.8 mm) and stiffness (52.2 ± 18.0 N/mm) compared to the sacroiliac screw (displacement 2.1 ± 0.6 mm, P >  0.999; stiffness 50.8 ± 13.0 N/mm, P > 0.999). Considering the anterior fracture site, the FiberTape® again demonstrated similar displacement (3.8 ± 1.3 mm) and stiffness (29.5 ± 9.0 N/mm) compared to the sacroiliac screw (displacement 2.9 ± 0.8 mm, P = 0.2196; stiffness 37.5 ± 11.5 N/mm, P = 0.0711). Conclusion The newly presented osteosynthesis, the FiberTape®, shows promising results for the stabilization of the posterior pelvic ring in AO Type B2.1 lateral compression fractures compared to a sacroiliac screw osteosynthesis based on its minimal-invasiveness and the statistically similar biomechanical properties.

scholarly journals The three-dimensional bone mass distribution of the posterior pelvic ring and its key role in transsacral screw placement

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Darius M. Thiesen ◽  
Dimitris Ntalos ◽  
Josephine Berger-Groch ◽  
Andreas Petersik ◽  
Bernhard Hofstätter ◽  
...  
Keyword(s):  
Bone Mass ◽  
Mass Distribution ◽  
Pelvic Ring ◽  
Three Dimensional ◽  
Screw Placement ◽  
Posterior Pelvic Ring

scholarly journals Extrinsic Calibration of Multiple Two-Dimensional Laser Rangefinders Based on a Trihedron

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1837 ◽  
Author(s):  
Fei Zhu ◽  
Yuchun Huang ◽  
Zizhu Tian ◽  
Yaowei Ma
Keyword(s):  
Autonomous Vehicles ◽  
Laser Scanning ◽  
Mobile Robotics ◽  
Three Dimensional ◽  
Point Problem ◽  
Two Dimensional ◽  
Simple Method ◽  
Extrinsic Calibration ◽  
Dimensional Reconstruction ◽  
Special Pattern

Multiple two-dimensional laser rangefinders (LRFs) are applied in many applications like mobile robotics, autonomous vehicles, and three-dimensional reconstruction. The extrinsic calibration between LRFs is the first step to perform data fusion and practical application. In this paper, we proposed a simple method to calibrate LRFs based on a corner composed of three mutually perpendicular planes. In contrast to other methods that require a special pattern or assistance from other sensors, the trihedron corner needed in this method is common in daily environments. In practice, we can adjust the position of the LRFs to observe the corner until the laser scanning plane intersects with three planes of the corner. Then, we formed a Perspective-Three-Point problem to solve the position and orientation of each LRF at the common corner coordinate system. The method was validated with synthetic and real experiments, showing better performance than existing methods.

scholarly journals Posterior pelvic ring fractures: Closed reduction and percutaneous CT-guided sacroiliac screw fixation

1997 ◽  
Vol 20 (4) ◽  
pp. 285-294 ◽  
Author(s):  
Augustinus Ludwig Jacob ◽  
Peter Messmer ◽  
Klaus-Wilhelm Stock ◽  
Norbert Suhm ◽  
Bernard Baumann ◽  
...  
Keyword(s):  
Closed Reduction ◽  
Screw Fixation ◽  
Pelvic Ring ◽  
Posterior Pelvic Ring ◽  
Ct Guided ◽  
Sacroiliac Screw ◽  
Pelvic Ring Fractures ◽  
Sacroiliac Screw Fixation

A method for the derivation of load effect envelopes based on statistical considerations

1993 ◽  
Vol 20 (2) ◽  
pp. 201-209
Author(s):  
Eugene J. O'Brien ◽  
Robert E. Loov
Keyword(s):  
Structural Analysis ◽  
Three Dimensional ◽  
Elastic Analysis ◽  
Two Dimensional ◽  
Statistical Parameters ◽  
Simple Method ◽  
Load Effect ◽  
Linear Elastic ◽  
Derived Design ◽  
Usual Process

A simple method is proposed as a substitute for the usual process of factoring loads, performing a linear elastic analysis, and determining an envelope of the results. The method is based on statistical principles, but only a minimum knowledge of statistics is required for its use. It involves conventional structural analysis followed by some processing of the results which could readily be incorporated into existing computer programs.The practice of performing two-dimensional analyses on parts of three-dimensional structures is possible with the proposed approach. The implications are clarified and the necessary statistical parameters are derived.Deterministically derived design envelopes represent all the extremes of loading that can reasonably be considered. The envelopes found by the new method not only reflect loading variations but also consider their relative probabilities of occurrence so that excursions beyond the envelope are expected to be equally infrequent along the entire length of the structure. Inconsistencies inherent in the conventional approach are highlighted by comparison with the proposed method for a number of examples. Key words: probabilistic, safety, load, imposed load, load effect envelope, building.

Three-dimensional, elastic stress distribution in end-milled, keyed connections

1983 ◽  
Vol 18 (2) ◽  
pp. 143-149 ◽  
Author(s):  
H Fessler ◽  
M Eissa
Keyword(s):  
Elastic Stress ◽  
Three Dimensional ◽  
Empirical Equations ◽  
Two Dimensional ◽  
Stress Concentrations ◽  
Axial Distribution ◽  
Simple Method ◽  
Torque Transmission ◽  
Applied Torque ◽  
Stress Models

Three- and two-dimensional, photoelastic, frozen-stress models of Standard metric and inch keyed connections have been loaded in torsion. Results from models with three different key lengths are presented here and related to the axial distribution of torque transmission. Empirical equations for the elastic stress concentrations in the prismatic part of key and keyway at the positions of contact between key and shaft have been derived for any likely width, thickness, and length of key, keyway fillet size, and applied torque. A simple method of eliminating stress concentrations in the keyway end is described.

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