A novel patient‐specific drill guide template for stabilization of thoracolumbar vertebrae of dogs: cadaveric study and clinical cases

2018 ◽  
Vol 48 (3) ◽  
pp. 336-342 ◽  
Author(s):  
Toru Fujioka ◽  
Kohei Nakata ◽  
Hidetaka Nishida ◽  
Taku Sugawara ◽  
Naoyuki Konno ◽  
...  
Keyword(s):  
Cadaveric Study ◽  
Patient Specific ◽  
Drill Guide ◽  
Drill Guide Template ◽  
Clinical Cases

A Novel Parsimonious Method as Accurate as Extravagant Counterparts: Streolithographically-Modeled Patient-Specific Drill Guide Template for Subaxial Cervical Pedicle Screw Insertion

2020 ◽  
Author(s):  
Mohammadreza Bozorgmanesh ◽  
Babak Siavashi ◽  
Mohammad Javad Zehtab ◽  
Ehsan Pendar ◽  
Yousef Fallah ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Latency Period ◽  
Patient Specific ◽  
Cervical Pedicle Screw ◽  
Screw Insertion ◽  
Drill Guide ◽  
Screw Diameter ◽  
Cervical Pedicle ◽  
The Stability ◽  
Drill Guide Template

Background: This study was conducted to develop a modified, parsimonious, faster to produce, easier to implement, and patient-specific drill guide template and also to examine if such a modification might affect the accuracy. Methods: On two cadaveric spines, using reverse engineering, the orientation of pedicles and safe corridors for pedicle screw were determined. A drill template was designed with a surface that was the inverse of the posterior vertebral surface. The drill template was manufactured using rapid prototyping technique. To decrease the costs, the cervical spine corresponding prototypes were not manufactured. In contrary to previous studies, to preserve the stability from posterior element, the templates were designed in such a way that removing interspinous and supraspinous ligaments was not necessary. The accuracy was evaluated by computed tomography (CT) images and classified into three grades of 0: correct placement, 1: malposition by less than a half screw diameter, and 2: malposition by more than a half screw diameter. Results: Of 20 positions available, we inserted 19 screws, because the trajectory of one of the patient-specific drill guide templates was misdirected. The overall accuracy rate for cervical pedicle screw (CPS) placement was 84.2% (16 of 19). Safely inserted screws, combining the grades 0 and 1 categories, were as high as 100%. We observed no “unsafe screw placement”. Conclusions: The total cost and the latency period before the operation was reduced and the interspinous and supraspinous ligaments were preserved. A good applicability and high accuracy was obtained for subaxial CPS (SCPS) insertion.

A low invasiveness patient’s specific template for spine surgery

2016 ◽  
Vol 231 (2) ◽  
pp. 143-148 ◽  
Author(s):  
Farhad Azimifar ◽  
Kamran Hassani ◽  
Amir Hossein Saveh ◽  
Farhad Tabatabai Ghomshe
Keyword(s):  
Pedicle Screw ◽  
Digital Technology ◽  
Screw Placement ◽  
Patient Specific ◽  
Computer Assisted ◽  
Pedicle Screw Placement ◽  
New Approach ◽  
Additive Manufacturing Technology ◽  
Drill Guide ◽  
Drill Guide Template

Free-hand pedicle screw placement is still conventional in surgery, although it has potentially high risks. The surgical procedures such as pedicle screw placement are usually designed based on medical imaging, but during surgery, the procedures are not normally followed due to the fact that some points are missed in two-dimensional images and seen only during surgery. In this regards, some highly accurate computer-assisted systems have been proposed and are currently used. Moreover, it is possible to reduce or completely avoid hand working by applying modern digital technology. Therefore, using these technologies has remarkable advantages. In this study, we have presented a new approach of pedicle screw placement in the lumbar and sacral regions using a specific drill guide template. The template was created by additive manufacturing technology and was verified in a clinical study as well. The main aim of this research includes the following: design, analyze, manufacture and evaluate the accuracy of a new patient-specific drill guide template, for lumbar pedicle screw placement, and compare the template to the free-hand technique under fluoroscopy supervision. Our results show that the incidence of cortex perforation is substantially reduced compared to existing methods. Finally, we believe that this approach remarkably lowers the incidence of cortex perforation and could be potentially used in clinical applications, particularly in certain selected cases.

scholarly journals A Novel Patient-Specific Drill Guide Template for Pedicle Screw Insertion into the Subaxial Cervical Spine Utilizing Stereolithographic Modelling: An <italic>In Vitro</italic> Study

2017 ◽  
Vol 11 (1) ◽  
pp. 4-14 ◽  
Author(s):  
Rafael Cruz Bundoc ◽  
Giorgio De Guzman Delgado ◽  
Samuel Arsenio Munoz Grozman
Keyword(s):  
Cervical Spine ◽  
Pedicle Screw ◽  
Cervical Vertebrae ◽  
Patient Specific ◽  
External Observer ◽  
Major Drawback ◽  
Screw Insertion ◽  
Subaxial Cervical Spine ◽  
Drill Guide ◽  
Drill Guide Template

<sec><title>Study Design</title><p>Cadaveric study.</p></sec><sec><title>Purpose</title><p>The purpose of this study was to assess the accuracy and feasibility of cervical pedicle screw (CPS) insertion into the subaxial cervical spine placed using a patient-specific drill guide template constructed from a stereolithographic model.</p></sec><sec><title>Overview of Literature</title><p>CPS fixation is an invaluable tool for posterior cervical fixation because of its biomechanical advantages. The major drawback is its narrow corridor that allows very little clearance for neural and vascular injuries.</p></sec><sec><title>Methods</title><p>Fifty subaxial pedicles of the cervical vertebrae from five cadavers were scanned into thin slices using computed tomography (CT). Digital imaging and communications in medicine images of the cadaver spine were digitally processed and printed to scale as a three-dimensional (3D) model. Drill guide templates were manually moulded over the 3D-printed models incorporating pins inserted in the pedicles. The drill guide templates were used for precise placement of the drill holes in the pedicles of cadaveric specimens for pedicle screw fixation.</p></sec><sec><title>Results</title><p>The instrumented cadaveric spines were subjected to CT to assess the accuracy of our pedicle placement by an external observer. Our patient-specific drill guide template had an accuracy of 94%.</p></sec><sec><title>Conclusions</title><p>The use of a patient-specific drill guide constructed using stereolithography improved the accuracy of CPS placement in a cadaveric model.</p></sec>

scholarly journals Automatic modelling of human musculoskeletal ligaments – Framework overview and model quality evaluation

2021 ◽  
pp. 1-14
Author(s):  
Noura Hamze ◽  
Lukas Nocker ◽  
Nikolaus Rauch ◽  
Markus Walzthöni ◽  
Matthias Harders ◽  
...  
Keyword(s):  
Statistical Model ◽  
Soft Tissues ◽  
Automatic Generation ◽  
Cadaveric Study ◽  
Patient Specific ◽  
Mean Square ◽  
Shape Modelling ◽  
Morphological Studies ◽  
Insertion Sites ◽  
Mean Square Errors

BACKGROUND: Accurate segmentation of connective soft tissues in medical images is very challenging, hampering the generation of geometric models for bio-mechanical computations. Alternatively, one could predict ligament insertion sites and then approximate the shapes, based on anatomical knowledge and morphological studies. OBJECTIVE: In this work, we describe an integrated framework for automatic modelling of human musculoskeletal ligaments. METHOD: We combine statistical shape modelling with geometric algorithms to automatically identify insertion sites, based on which geometric surface/volume meshes are created. As clinical use case, the framework has been applied to generate models of the forearm interosseous membrane. Ligament insertion sites in the statistical model were defined according to anatomical predictions following a published approach. RESULTS: For evaluation we compared the generated sites, as well as the ligament shapes, to data obtained from a cadaveric study, involving five forearms with 15 ligaments. Our framework permitted the creation of models approximating ligaments’ shapes with good fidelity. However, we found that the statistical model trained with the state-of-the-art prediction of the insertion sites was not always reliable. Average mean square errors as well as Hausdorff distances of the meshes could increase by an order of magnitude, as compared to employing known insertion locations of the cadaveric study. Using those, an average mean square error of 0.59 mm and an average Hausdorff distance of less than 7 mm resulted, for all ligaments. CONCLUSIONS: The presented approach for automatic generation of ligament shapes from insertion points appears to be feasible but the detection of the insertion sites with a SSM is too inaccurate, thus making a patient-specific approach necessary.

scholarly journals Novel 3-dimensionally printed patient-specific guide improves accuracy compared with standard total shoulder arthroplasty guide: a cadaveric study

2019 ◽  
Vol 3 (2) ◽  
pp. 83-92 ◽  
Author(s):  
Brandon C. Cabarcas ◽  
Gregory L. Cvetanovich ◽  
Alejandro A. Espinoza Orías ◽  
Nozomu Inoue ◽  
Anirudh K. Gowd ◽  
...  
Keyword(s):  
Shoulder Arthroplasty ◽  
Total Shoulder Arthroplasty ◽  
Cadaveric Study ◽  
Patient Specific

Accuracy of Patient-Specific 3D Printed Drill Guides in the Placement of a Canine Coxofemoral Toggle Pin through a Minimally Invasive Approach

2020 ◽  
Author(s):  
Brett G. Darrow ◽  
Kyle A. Snowdon ◽  
Adrien Hespel
Keyword(s):  
Minimally Invasive ◽  
Three Dimensional ◽  
Bone Tunnel ◽  
Patient Specific ◽  
Exit Point ◽  
Minimally Invasive Approach ◽  
Invasive Approach ◽  
Post Procedure ◽  
Drill Guide ◽  
Ct Data

Abstract Objective The aim of this study was to evaluate the accuracy of patient-specific three-dimensional printed drill guides (3D-PDG) for the placement of a coxofemoral toggle via a minimally invasive approach. Materials and Methods Pre-procedure computed tomography (CT) data of 19 canine cadaveric hips were used to design a cadaver-specific 3D-PDG that conformed to the proximal femur. Femoral and acetabular bone tunnels were drilled through the 3D-PDG, and a coxofemoral toggle pin was placed. The accuracy of tunnel placement was evaluated with post-procedure CT and gross dissection. Results Coxofemoral toggle pins were successfully placed in all dogs. Mean exit point translation at the fovea capitis was 2.5 mm (0.2–7.5) when comparing pre- and post-procedure CT scans. Gross dissection revealed the bone tunnel exited the fovea capitis inside (3/19), partially inside (12/19) and outside of (4/19) the ligament of the head of the femur. Placement of the bone tunnel through the acetabulum was inside (16/19), partially inside (1/19) and outside (2/19) of the acetabular fossa. Small 1 to 2 mm articular cartilage fragments were noted in 10 of 19 specimens. Clinical Significance Three-dimensional printed drill guide designed for coxofemoral toggle pin application is feasible. Errors are attributed to surgical execution and identification of the borders of the fovea capitis on CT data. Future studies should investigate modifications to 3D-PDG design and methods. Three-dimensional printed drill guide for coxofemoral toggle pin placement warrants consideration for use in select clinical cases of traumatic coxofemoral luxation.

scholarly journals Determination of dominant loop in dual loop atrial tachycardia with direct graph mapping: an alternative for entrainment mapping?

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
L Lowie ◽  
E Van Nieuwenhuyse ◽  
J Sanchez ◽  
A Panfilov ◽  
S Knecht ◽  
...  
Keyword(s):  
Simulated Data ◽  
Anterior Wall ◽  
Specific Model ◽  
Patient Specific ◽  
Double Loop ◽  
Direct Graph ◽  
Funding Sources ◽  
Graph Mapping ◽  
Activation Times ◽  
Clinical Cases

Abstract Funding Acknowledgements Type of funding sources: None. Background Entrainment mapping (EM) is an important tool to determine the mechanism of complex reentrant atrial tachycardias (ATs), mostly to distinguish dominant from bystander reentrant loops. However, entrainment maneuvers are challenging, time consuming and risk to end the tachycardia.  Purpose Recently, we developed a novel method Directed Graph Mapping (DGM), using concepts of network theory, allowing to automatically determine AT reentry loops from the local activation times (LAT) of any clinical mapping system. DGM showed good performance: it correctly finds ablation target (100 % success rate) on simple AT cases and could automatically determine reentry loops confirmed by the expert electrophysiologist with EM in complex AT cases. Out of 32 single loop cases, 62.5 % was identified correctly with automated DGM and out of 6 true double loop cases, 83.3 %. Lower performance for single reentry complex cases compared to EM was mainly because DGM could not distinguish the dominant loop from additional bystander loops found by DGM. Hence, the purpose of this work was to develop additional algorithms which in case of multiple found DGM loops could automatically find the dominant loop and compare it with the results of EM. Methods We performed multiple  simulations of various types of double loop reentry on a patient specific model of the left atrium. Based on a clinical case, double loops were simulated around a scar at the anterior wall (localized reentry) and the mitral valve (MV). LAT maps were determined similar as in the clinic. By varying the size of the scar in multiple steps, we obtained a transition from a regime of a dominant loop around the scar (small scar), to a true double loop and further to a regime of a dominant loop around the MV (large scar). We developed a novel DGM algorithm to determine the dominant loop from the region of collision (ROC) found from the vector field of the wavefront graph.   The developed method was also tested on 8 clinical cases of double loop ATs with EM measurements. Results Our algorithm found the location of the ROC and determined the correct dominant loop in 100% of the simulated data.  We tested this on 8 clinical cases of AT, and accuracy of the method was 75 %. Conclusions Determining the ROC in case of multiple loops in AT could correctly determine the dominant versus bystander loop, leading to the correct ablation target, without the need for further EM.

Sign in / Sign up

Export Citation Format

Share Document