scholarly journals Orthopedic hexapods: history, present and prospects

2015 ◽  
Vol 3 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Viktor Aleksandrovich Vilensky ◽  
Aleksander Pavlovich Pozdeev ◽  
Edgar Valentinovich Bukharev ◽  
Andrey Aleksandrovich Pozdeev ◽  
Timur Faizovich Zubairov ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Deformity Correction ◽  
Long Bone ◽  
Computer Assisted ◽  
Software Application ◽  
Six Degrees Of Freedom ◽  
Fixation Devices ◽  
Special Software ◽  
History Of ◽  
Bone Fragments

The article is dedicated to computer-assisted external fixation devices, so-called hexapods. The main advantage of these frames is capability to make mathematically precise correction of bone fragments in three planes and six degrees of freedom on the base of calculations made in special software application. Recently these devices are mostly applied in long bone deformity correction but the sphere of its effective useis not limited by only this direction. The article presents the history of investigation of these devices, their development, implemented comparative analysis of the basic hexapods: TSF (Taylor Spatial Frame), IHA (Ilizarov Hexapod Apparatus) and Ortho-SUV Frame.

Found in Space: Computer-Assisted Orthognathic Alignment of a Total Face Allograft in Six Degrees of Freedom

2014 ◽  
Vol 72 (9) ◽  
pp. 1788-1800 ◽  
Author(s):  
Amir H. Dorafshar ◽  
Philip S. Brazio ◽  
Gerhard S. Mundinger ◽  
Raja Mohan ◽  
Emile N. Brown ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Computer Assisted ◽  
Six Degrees Of Freedom

The Wide-Open Three-Legged Parallel Robot for Long-Bone Fracture Reduction

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Mohammad H. Abedinnasab ◽  
Farzam Farahmand ◽  
Jaime Gallardo-Alvarado
Keyword(s):  
Bone Fracture ◽  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Parallel Robot ◽  
High Accuracy ◽  
Fracture Reduction ◽  
Long Bone ◽  
Long Bones ◽  
Six Degrees Of Freedom ◽  
Long Bone Fracture

Robotic reduction of long bones is associated with the need for considerable force and high precision. To balance the accuracy, payload, and workspace, we have designed a new six degrees-of-freedom three-legged wide-open robotic system for long-bone fracture reduction. Thanks to the low number of legs and their nonsymmetrical configuration, the mechanism enjoys a unique architecture with a frontally open half-plane. This facilitates positioning the leg inside the mechanism and provides a large workspace for surgical maneuvers, as shown and compared to the well-known Gough–Stewart platform. The experimental tests on a phantom reveal that the mechanism is well capable of applying the desired reduction steps against the large muscular payloads with high accuracy.

Kinematic Analysis and Design of a Six-Degrees of Freedom 3-RRPS Mechanism for Bone Reduction Surgery

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Terence Essomba ◽  
Sinh Nguyen Phu
Keyword(s):  
Degrees Of Freedom ◽  
Vertical Axis ◽  
Velocity Model ◽  
Analysis And Design ◽  
Six Degrees Of Freedom ◽  
Bone Fragments ◽  
Kinematic Models ◽  
Surgery First ◽  
Forward Kinematic ◽  
Classical Mechanism

Abstract Robot-assisted bone reduction surgery consists in using robots to reposition the bone fragments into their original place prior to fracture healing. This study presents the application of a 3-RRPS augmented tripod mechanism with six degrees-of-freedom for longitudinal bone reduction surgery. First, the inverse and forward kinematic models of the mechanism are investigated. Particularly, the forward kinematic is solved by applying Sylvester's dialytic method. Second, the velocity model is studied and its singular configurations are identified. The workspace of the 3-RRPS mechanism is then outlined and compared with the Stewart platform, which is a classical mechanism for the targeted application. The results show that this mechanism provides a larger workspace, especially its rotation angle about the vertical axis, which is an important aspect in the bone reduction. A series of simulations on the numerical and graphic software is performed to verify the entire analysis of the parallel mechanism. A physiguide and mscadams software are used to carry out a simulation of a real case of femur fracture reduction using the proposed mechanism to validate its suitability. Finally, a robotic prototype based on the mechanism is manufactured and experimented using an artificial bone model to evaluate the feasibility of the mechanism.

scholarly journals Long bone fracture reduction and deformity correction using the hexapod external fixator with a new method: a feasible study and preliminary results

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yanshi Liu ◽  
Hong Li ◽  
Jialin Liu ◽  
Xingpeng Zhang ◽  
Maimaiaili Yushan ◽  
...  
Keyword(s):  
Soft Tissue ◽  
External Fixator ◽  
Bone Fracture ◽  
Three Dimensional ◽  
Deformity Correction ◽  
Fracture Reduction ◽  
Long Bone ◽  
Computer Assisted ◽  
Electronic Prescription ◽  
Long Bone Fracture

Abstract Background The hexapod external fixator (HEF), such as the Taylor spatial frame (TSF), offering the ability of multidirectional deformities correction without changing the structure, whereas there are so many parameters for surgeons to measure and subjective errors will occur inevitably. The purpose of this study was to evaluate the effectiveness of a new method based on computer-assisted three-dimensional (3D) reconstruction and hexapod external fixator for long bone fracture reduction and deformity correction without calculating the parameters needed by the traditional usage. Methods This retrospective study consists of 25 patients with high-energy tibial diaphyseal fractures treated by the HEF at our institution from January 2016 to June 2018, including 22 males and 3 females with a mean age of 42 years (range 14–63 years). Hexapod external fixator treatments were conducted to manage the multiplanar posttraumatic deformities with/without poor soft-tissue that were not suitable for internal fixation. Computer-assisted 3D reconstruction and trajectory planning of the reduction by Mimics were applied to perform virtual fracture reduction and deformity correction. The electronic prescription derived from the length changes of the six struts were calculated by SolidWorks. Fracture reduction was conducted by adjusting the lengths of the six struts according to the electronic prescription. Effectiveness was evaluated by the standard anteroposterior (AP) and lateral X-rays after reduction. Results All patients acquired excellent functional reduction and achieved bone union in our study. After correction, the mean translation (1.0 ± 1.1 mm) and angulation (0.8 ± 1.2°) on the coronal plane, mean translation (0.8 ± 1.0 mm) and angulation (0.3 ± 0.8°) on the sagittal plane were all less than those (6.1 ± 4.9 mm, 5.2 ± 3.2°, 4.2 ± 3.5 mm, 4.0 ± 2.5°) before correction (P < 0.05). Conclusions The computer-assisted three-dimensional reconstruction and hexapod external fixator-based method allows surgeons to conduct long bone fracture reduction and deformity correction without calculating the parameters needed by the traditional usage. This method is suggested to apply in those unusually complex cases with extensive soft tissue damage and where internal fixation is impossible or inadvisable.

Doma: a new multi-technological lithic occurrence in the Lower Son Valley (north-central India) and its regional context

2021 ◽  
pp. SP515-2020-205
Author(s):  
Shashi B. Mehra
Keyword(s):  
Central India ◽  
Raw Material ◽  
Long Bone ◽  
Sedimentary Sequence ◽  
Initial Report ◽  
North Central ◽  
History Of ◽  
Bone Fragments ◽  
Topographical Mapping ◽  
Mammalian Fossil

AbstractThe Lower Son Valley is generally overlooked despite a lengthy history of archaeological and geological studies in the adjacent Middle Son Valley. However, recent explorations in the former have yielded a large number of Palaeolithic and microlithic sites. This paper provides an initial report on Doma, a newly discovered site with the first-known stratified bifaces in this part of the valley. The site preserves multi-period technologies in different contexts including terminal Acheulean/early Middle Palaeolithic, and Upper Palaeolithic (all tentatively assigned based on respective typologies). Preliminary field observations are presented on the sedimentary sequence, archaeological surveys, topographical mapping, raw material, and the overall palaeoanthropological assessment of Doma. The raw material utilised at the site is primarily porcellanite, derived from exposures of the Semri Group of the Vindhyan Supergroup. The oldest Palaeolithic evidence at Doma broadly resembles Late Acheulean sites dated to ∼140-120 ka in the nearby Middle Son Valley. The Pleistocene sediments here also yielded mammalian fossil specimens such as long bone fragments, dental specimens and antler fragments. Along with the lithics and fossils, the site also preserves datable sedimentary sequence with calcrete, all key proxies to develop a testable model of technological transitions within a palaeoenvironmental framework, in the future.

scholarly journals Long Bone Fracture Reduction and Deformity Correction Using the Hexapod External Fixator With a New Method: a Feasible Study and Preliminary Results

2020 ◽  
Author(s):  
Yanshi Liu ◽  
Hong Li ◽  
Jialin Liu ◽  
Xingpeng Zhang ◽  
Maimaiaili Yushan ◽  
...  
Keyword(s):  
External Fixator ◽  
Bone Fracture ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Deformity Correction ◽  
Fracture Reduction ◽  
Long Bone ◽  
Computer Assisted ◽  
Electronic Prescription ◽  
Long Bone Fracture

Abstract Background: The hexapod external fixator (HEF), such as the Taylor spatial frame (TSF), offering the ability of simultaneous correction of the multidirectional deformities without frame modification, whereas there are so many parameters for surgeons to measure and subjective errors will occur inevitably. The purpose of this study was to evaluate the effectiveness of a new method based on computer-assisted three-dimensional (3D) reconstruction and hexapod external fixator for long bone fracture reduction and deformity correction without calculating the parameters needed by the computer program.Methods: This retrospective study consists of 25 patients with high-energy tibial diaphyseal fractures treated by the HEF at our institution from January 2016 to June 2018, including 22 males and 3 females with a mean age of 42 years (range 14-63 years). Hexapod external fixator treatments were performed due to primary and definitive management of multiplanar posttraumatic deformity and/or severe soft-tissue damage that were not suitable for internal fixation in the tibia. Computer-assisted 3D reconstruction and trajectory planning of the reduction by Mimics were applied to perform virtual fracture reduction and deformity correction. The electronic prescription derived from the length changes of the six struts were calculated by SolidWorks. Fracture reduction was conducted by adjusting the lengths of the six struts according to the electronic prescription. The standard anteroposterior (AP) and lateral X-rays after reduction were taken to evaluate the effectiveness.Results: All patients acquired excellent functional reduction (most cases achieved anatomical reduction) in our study. The mean coronal plane translation (1.0±1.1 mm), coronal plane angulation (0.8±1.2°), sagittal plane translation (0.8±1.0 mm) and sagittal plane angulation (0.3±0.8°) after correction were all less than those (6.1±4.9 mm, 5.2±3.2°, 4.2±3.5 mm, 4.0±2.5°) before correction (P<0.05).Conclusion: The computer-assisted three-dimensional reconstruction and hexapod external fixator-based method allows surgeons to conduct long bone fracture reduction and deformity correction without calculating the parameters needed by the computer program. Considering the radiologic exposure, this method is suggested to apply in those unusually complex cases with extensive soft tissue damage and internal fixation is impossible or inadvisable.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

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