scholarly journals Intraoperative 3D imaging with cone-beam computed tomography leads to revision of pedicle screws in dorsal instrumentation: a retrospective analysis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Felix Zimmermann ◽  
Katharina Kohl ◽  
Maxim Privalov ◽  
Jochen Franke ◽  
Sven Y. Vetter
Keyword(s):  
Computed Tomography ◽  
3D Imaging ◽  
Intraoperative Imaging ◽  
Pedicle Screws ◽  
Type A ◽  
Cone Beam ◽  
Type B ◽  
Intraoperative 3D Imaging ◽  
Screw Position ◽  
Type C

Abstract Background Correct positioning of pedicle screws can be challenging. Intraoperative imaging may be helpful. The purpose of this study was to evaluate the use of intraoperative 3D imaging with a cone-beam CT. The hypotheses were that intraoperative 3D imaging (1) will lead to an intraoperative revision of pedicle screws and (2) may diminish the rate of perforated screws on postoperative imaging. Methods Totally, 351 patients (age 60.9 ± 20.3 a (15–96); m/f 203/148) underwent dorsal instrumentation with intraoperative 3D imaging with 2215 pedicle screws at a trauma center level one. This study first evaluates intraoperative imaging. After this, 501 screws in 73 patients (age 62.5 ± 19.7 a; m/f 47/26) of this collective were included in the study group (SG) and their postoperative computed tomography was evaluated with regard to screw position. Then, 500 screws in 82 patients (age 64.8 ± 14.4 a; m/f 51/31) as control group (CG), who received the screws with conventional 2D fluoroscopy but without 3D imaging, were evaluated with regard to screw position. Results During the placement of the 2215 pedicle screws, 158 (7.0%) intraoperative revisions occurred as a result of 3D imaging. Postoperative computed tomography of the SG showed 445 (88.8%) screws without relevant perforation (type A + B), of which 410 (81.8%) could be classified as type A and 35 (7.0%) could be classified as type B. Fifty-six (11.2%) screws in SG showed relevant perforation (type C–E). In contrast, 384 (76.8%) screws in the CG were without relevant perforation (type A + B), of which 282 (56.4%) could be classified as type A and 102 (20.4%) as type B. One hundred and sixteen (23.2%) screws in the CG showed relevant perforation (type C–E). Conclusion This study shows that correct placement of pedicle screws in spine surgery with conventional 2D fluoroscopy is challenging. Misplacement of screws cannot always be prevented. Intraoperative 3D imaging with a CBCT can be helpful to detect and revise misplaced pedicle screws intraoperatively. The use of intraoperative 3D imaging will probably minimize the number of revision procedures due to perforating pedicle screws.

scholarly journals Intraoperative 3D Imaging with Cone-Beam Computed Tomography Leads to Revision of Pedicle Screws in Dorsal Instrumentation – A Retrospective Analysis.

2021 ◽  
Author(s):  
Felix Zimmermann ◽  
Katharina Kohl ◽  
Maxim Privalov ◽  
Jochen Franke ◽  
Sven Yves Vetter
Keyword(s):  
Computed Tomography ◽  
3D Imaging ◽  
Intraoperative Imaging ◽  
Pedicle Screws ◽  
Type A ◽  
Cone Beam ◽  
Type B ◽  
Intraoperative 3D Imaging ◽  
Screw Position ◽  
Type C

Abstract Background: Correct positioning of pedicle screws can be challenging. Intraoperative imaging may be helpful. The purpose of this study was to evaluate the use of intraoperative 3D imaging with a cone-beam CT. The hypotheses were that intraoperative 3D imaging (1) will lead to an intraoperative revision of pedicle screws and (2) may diminish the rate of perforated screws on postoperative imaging.Methods: 351 patients (age 60.9 ± 20.3 a (15-96); m/f 203/148) underwent dorsal instrumentation with intraoperative 3D imaging with 2215 pedicle screws at a trauma center level one. This study first evaluates the intraoperative imaging. After this, 501 screws in 73 patients (age 62.5 ± 19.7 a; m/f 47/26) of this collective were included in the study group (SG) and their postoperative computed tomography was evaluated with regard to screw position. Then 500 screws in 82 patients (age 64.8 ± 14.4 a; m/f 51/31) as control group (CG), who received the screws with conventional 2D fluoroscopy but without 3D imaging, were evaluated with regard to screw position. Results: During the placement of the 2215 pedicle screws 158 (7.0%) intraoperative revisions occurred as a result of 3D imaging. Postoperative computed tomography of the SG showed 445 (88.8%) screws without relevant perforation (type A+B), of which 410 (81.8%) could be classified as type A and 35 (7.0%) could be classified as type B. 56 (11.2%) screws in SG showed relevant perforation (type C-E). In contrast, 384 (76.8%) screws in the CG were without relevant perforation (type A+B), of which 282 (56.4%) could be classified as type A and 102 (20.4%) as type B. 116 (23.2%) screws in the CG showed relevant perforation (type C-E).Conclusion: This study shows that correct placement of pedicle screws in spine surgery with conventional 2D fluoroscopy is challenging. Misplacement of screws cannot always be prevented. Intraoperative 3D imaging with a CBCT can be helpful to detect and revise misplaced pedicle screws intraoperatively. The use of intraoperative 3D imaging will probably minimize the number of revision procedures due to perforating pedicle screws.

Novel Surgical and Radiologic Classification of the Subtympanic Sinus: Implications for Endoscopic Ear Surgery

2018 ◽  
Vol 159 (6) ◽  
pp. 1037-1042 ◽  
Author(s):  
Lukas Anschuetz ◽  
Matteo Alicandri-Ciufelli ◽  
Marco Bonali ◽  
Matteo Fermi ◽  
Marco Caversaccio ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Type A ◽  
Mastoid Cavity ◽  
Endoscopic Ear Surgery ◽  
Type B ◽  
High Resolution Computed Tomography ◽  
Ear Surgery ◽  
Endoscopic Anatomy ◽  
Type C

Objective The aim of this study is to describe the endoscopic anatomy of the subtympanic sinus (STS), establish a classification according to its extension regarding the level of the facial nerve (FN), and assess the feasibility of the transcanal endoscopic approach to the STS. Study Design Experimental anatomic research. Setting Temporal bone laboratory. Methods We performed endoscopic dissection of 34 human whole head and ear block specimens. Of those, 29 underwent high-resolution computed tomography. The STS was classified according to its extension regarding the level of the FN: type A, no extension medial to the FN; type B, extension to the medial limit of the FN; type C, extension of the sinus medially and posteriorly from the FN into the mastoid cavity. Results The majority of cases (n = 21, 72%) showed a shallow type A STS. We observed a deep type B configuration in 6 cases (21%) and a type C in 2 cases (7%). The STS was completely exposable with a 0° endoscope in 44% of the specimens. Using a 45° endoscope, we gained complete insight in 79%. However, in 21% of the cases, the posteromedial extension of the STS was too deep to be completely explored by an endoscopic transcanal approach. Conclusion The majority of the STS is shallow and does not extend medially from the FN. This morphologic variant allows complete transcanal endoscopic visualization. In more excavated STS, a complete endoscopic exploration is not achievable, and a retrofacial approach may be adopted to completely access the STS.

scholarly journals The effectiveness of TiO2 additions to mortar to maintain initial conditions in terms of its reflectance to solar radiation

2017 ◽  
Vol 17 (3) ◽  
pp. 39-56 ◽  
Author(s):  
Sérgio Roberto Andrade Dantas ◽  
Fulvio Vittorino ◽  
Kai Loh
Keyword(s):  
Solar Radiation ◽  
Ultraviolet Radiation ◽  
Initial Conditions ◽  
Type A ◽  
Just Noticeable Difference ◽  
Type B ◽  
Climate Conditions ◽  
Type D ◽  
Type C ◽  
Over Time

Abstract Contact of facades with degradation agents and direct incidence of ultraviolet radiation on external coatings make them more opaque over time, affecting their colour and reflectance characteristics. This study evaluated the effect of adding different TiO2 contents to mortars applied in concrete substrates in order to verify the reflectance maintenance on surfaces after exposure over time. Mortar with different concentrations of TiO2 (1%, 5%, 10%) were produced in relation to the total dry premix, added as a powder and compared to unpainted mortar without TiO2 (type "A") and painted mortar without TiO2 (type "B"), both used as a reference for colour and reflectance. Exposed over 16 months to climate conditions in São Paulo, regarding the maintenance of reflectance and solar radiation, the results showed that type "B" (0%TiO2) painted mortar presented the best performance. Type "C" (1%TiO2) and type "D" (5%TiO2) unpainted mortar remained more stable. Type "A" (0%TiO2) and type "E" (10%TiO2) unpainted mortar showed greater differences according to the Just Noticeable Difference (JND) range caused by dirt pick up.

Judgments of Grammatically by Normal and Language-Disordered Children

1977 ◽  
Vol 42 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Betty Z. Liles ◽  
Martin D. Shulman ◽  
Susan Bartlett
Keyword(s):  
Word Order ◽  
Sentence Type ◽  
Type A ◽  
Order Type ◽  
Specific Reference ◽  
Type B ◽  
Normal Children ◽  
Grammatical Errors ◽  
Type C

Fifteen linguistically normal children and 15 linguistically deviant children were presented with three types of agrammatical sentences. The subjects were asked to judge the sentences as right or wrong and to change the sentences judged as wrong, rendering them correct. The three types of agrammatical sentences represented rule violations of syntactic agreement (Type A), lexical restrictions (Type B), and word order (Type C). The two groups of children were compared in terms of the number of sentences of each type that were recognized as agrammatical. Those productions which represented the child’s correction of agrammatical sentences were subjected to descriptive analyses (percentages) with specific reference to the number of attempted changes and the number of those changes which demonstrated corrections of the specific deviation from well formedness. Results indicated that the two groups of subjects were significantly different in their ability to recognize grammatical errors in sentence Types A and C, but did not differ in their ability to recognize errors in sentence Type B. The descriptive comparison of the groups' verbal corrections reflected this trend, in that the language-disordered subjects made corrections specific to the error on more of the Type B sentences (for example, “The dog writes the food.”) than on Types A (for example, “'She will pick some flowers last week.”) or C (for example, “Get and come your dinner.”). Linguistically normal children accurately corrected 90.7% of the sentences judged as agrammatical; this percentage did not vary more than 1% across sentence types.

scholarly journals Structural and fractal characterization of adsorption pores of middle–high rank coal reservoirs in western Yunnan and eastern Guizhou: An experimental study of coals from the Panguan syncline and Laochang anticline

2018 ◽  
Vol 37 (1) ◽  
pp. 251-272 ◽  
Author(s):  
Junjian Zhang ◽  
Chongtao Wei ◽  
Gaoyuan Yan ◽  
Guanwen Lu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Structural Parameters ◽  
Total Pore Volume ◽  
Type A ◽  
Type B ◽  
Type C

To better understand the structural characteristic of adsorption pores (pore diameter < 100 nm) of coal reservoirs around the coalbed methane production areas of western Yunnan and eastern Guizhou, we analyzed the structural and fractal characteristics of pore size range of 0.40–2.0 nm and 2–100 nm in middle–high rank coals ( Ro,max = 0.93–3.20%) by combining low-temperature N2/CO2 adsorption tests and surface/volume fractal theory. The results show that the coal reservoirs can be divided into three categories: type A ( Ro,max < 2.15%), type B (2.15% <  Ro,max <2.50%), and type C ( Ro,max > 2.15%). The structural parameters of pores in the range from 2 to 100 nm are influenced by the degree of coal metamorphism and the compositional parameters (e.g., ash and volatile matter). The dominant diameters of the specific surface areas are 10–50 nm, 2–50 nm, and 2–10 nm, respectively. The pores in the range from <2 nm provide the largest proportion of total specific surface area (97.22%–99.96%) of the coal reservoir, and the CO2-specific surface area and CO2-total pore volume relationships show a positive linear correlation. The metamorphic degree has a much greater control on the pores (pore diameter less than 2 nm) structural parameters than those of the pore diameter ranges from 2 to 100 nm. Dv1 and Dv2 can characterize the structure of 2–100 nm adsorption pores, and Dv1 (volume heterogeneity) has a positive correlation with the pore structural parameters such as N2-specific surface area and N2-total pore volume. This parameter can be used to characterize volume heterogeneity of 2–10 nm pores. Dv2 (surface heterogeneity) showed type A > type B > type C and was mainly affected by the metamorphism degree. Ds2 can be used to characterize the pore surface heterogeneity of micropores in the range of 0.62–1.50 nm. This parameter has a good correlation with the pore parameters (CO2-total pore volume, CO2-specific surface area, and average pore size) and is expressed as type C < type B < type A. In conclusion, the heterogeneity of the micropores is less than that of the meso- and macropores (2–100 nm). Dv1, Dv2, and Ds2 can be used as effective parameters to characterize the pore structure of adsorption pores. This result can provide a theoretical basis for studying the pore structure compatibility of coal reservoirs in the region.

scholarly journals Postsurgical residual lung complications following left upper trisegmentectomy

2019 ◽  
Author(s):  
Yutaro Koike ◽  
Aritoshi Hattori ◽  
Takeshi Matsunaga ◽  
Kazuya Takamochi ◽  
Shiaki Oh ◽  
...  
Keyword(s):  
Surgical Intervention ◽  
Type A ◽  
X Rays ◽  
Limited Information ◽  
Type B ◽  
Type D ◽  
Thoracic Computed Tomography ◽  
Isolated Segment ◽  
Type C ◽  
Lung Torsion

AbstractOBJECTIVESSegmentectomy has become an increasingly popular surgical procedure for small-sized lung lesions. Left upper trisegmentectomy (LUTS) is one of the most common segmentectomies performed because of its relative ease and simplicity; however, limited information is currently available on the specific postoperative complications associated with this procedure.METHODSAmong 2060 surgically resected cases in our institute between 2009 and 2016, 129 (6.2%) underwent LUTS. Postoperative chest X-rays and/or thoracic computed tomography (CT) scans were retrospectively assessed for all cases to assess postsurgical residual lung complications following LUTS. We categorized cases into 4 groups: type A (atelectasis of the lingular segment), type B (lung torsion of the lingular segment), type C (necrosis of the ‘isolated segment’) and type D (haematoma along stapling lines).RESULTSPostsurgical lung complications following LUTS were observed in 17 (13.1%) patients (type A: n = 7, type B: n = 1, type C: n = 4 and type D: n = 5). Three patients (2.3%) required surgical intervention because of type B (n = 1) and type C (n = 2), namely, decreased permeability and remaining ground glass opacities in the residual lung, showing an exacerbated systemic inflammatory response. In contrast, type A and D cases were successfully observed by chest CT without any surgical intervention, and patients recovered within a few months of surgery.CONCLUSIONSWe identified several postoperative residual lung complications following LUTS. Lung torsion or necrosis of the residual segment may require intensive care, including reoperation. Potentially serious complications always need to be ruled out after LUTS when radiological consolidation is detected postoperatively.

Research on Flow Units of Extra-Low Permeability Reservoirs in Fault Block Sheng554 of Shengping Oilfield

2013 ◽  
Vol 295-298 ◽  
pp. 3162-3165
Author(s):  
Lu Lu Zhou ◽  
Zi Nan Li ◽  
Jun Gang Liu ◽  
Yan Yun Zhang ◽  
Guang Qiang Shu
Keyword(s):  
Fluid Flow ◽  
Water Injection ◽  
Type A ◽  
Low Permeability ◽  
Type B ◽  
Flow Units ◽  
Fault Block ◽  
Remaining Oil ◽  
Type C ◽  
Low Permeability Reservoirs

Taking the example of the fourth member of the Lower Cretaceous Quantou formation reservoirs in fault block Sheng554 of Sanzhao sag, this article discusses the methodology of flow units in extra-low permeability reservoirs. The research on flow units in such reservoirs can be divided into two ranks, one is to determine the distribution of seepage barriers and inner connected sands， the other is to analyze the differentia of fluid flow in the inner connected sands so as to subdivide the flow units. The result shows that the pelitic barriers are rather developed in fault block Sheng554. Through the analysis of differentia of fluid flow, according to the value of flow zone index (FZI), the inner connected sands can be classified into three types of flow units, among which type A with FZI value greater than 1.0 has better permeable property and higher intensity of water injection, and the ability of permeability and water injection of type B with FZI value between 0.5 and 1.0 takes the second place, and type C is the worst flow unit with the worst permeable property and intensity of water injection with FZI value less than 0.5. Among the three types of flow units, type A poorly develops, while type B and type C develops well. The research on flow units can provide reliable geologic bases for forecasting the distribution of remaining oil in extra-low permeability reservoirs and for developing remaining oil in the study area.

A New Classification of Cochleovestibular Malformations and Implications for Predicting Speech Perception Ability after Cochlear Implantation

2015 ◽  
Vol 20 (2) ◽  
pp. 90-101 ◽  
Author(s):  
Sung-Wook Jeong ◽  
Lee-Suk Kim
Keyword(s):  
Speech Perception ◽  
Cochlear Implantation ◽  
Test Scores ◽  
Type A ◽  
Cochlear Nerve ◽  
Type B ◽  
New Classification ◽  
Type D ◽  
Type C

Objectives: The aims of this study were to introduce a new classification of cochleovestibular malformation (CVM) and to investigate how well this classification can predict speech perception ability after cochlear implantation in children with CVM. Methods: Fifty-nine children with CVM who had used a cochlear implant for more than 3 years were included. CVM was classified into 4 subtypes based on the morphology of the cochlea and the modiolus on temporal bone computed tomography (TBCT): normal cochlea and normal modiolus (type A, n = 16), malformed cochlea and partial modiolus (type B, n = 31), malformed cochlea and no modiolus (type C, n = 6), and no cochlea and no modiolus (type D, n = 6). Speech perception test scores were compared between the subtypes of CVM using analysis of covariance with post hoc Bonferroni test. Univariate and multivariate regression analyses were used to identify the significant predictors of the speech perception test scores. Results: The speech perception test scores after implantation were significantly better in children with CVM type A or type B than in children with CVM type C or type D. The test scores did not differ significantly between the implanted children with CVM type A or type B and those without CVM. In univariate regression analysis, the type of CVM was a significant predictor of the speech perception test scores in implanted children with CVM. Multivariate regression analysis revealed that the age at cochlear implantation, cochlear nerve size and preimplantation speech perception test scores were significant predictors of the postimplantation speech perception test scores. The chance of cochlear nerve deficiency increased progressively from CVM type A to type D. Conclusion: The new classification of CVM based on the morphology of the cochlea and the modiolus is simple and easy to use, and correlated well with postimplantation speech perception ability and cochlear nerve status. This simple classification of CVM using TBCT with cochlear nerve assessment by magnetic resonance imaging is helpful in the preoperative evaluation of children with CVM.

scholarly journals A Simple Technique for Interventional Tool Placement Combining Fluoroscopy With Interventional Computed Tomography on a C-Arm System

2010 ◽  
Vol 67 (3) ◽  
pp. ons49-ons57 ◽  
Author(s):  
Brian E. Nett ◽  
Beverly Aagaard-Kienitz ◽  
Yurdal Serarslan ◽  
Mustafa K. Başkaya ◽  
Guang-Hong Chen
Keyword(s):  
Computed Tomography ◽  
Intraoperative Imaging ◽  
Cone Beam ◽  
Preoperative Imaging ◽  
Clinical Feature ◽  
Flat Panel ◽  
Guided Surgery ◽  
Surgical Tool ◽  
Contrast Enhanced ◽  
Needle Trajectory

Abstract BACKGROUND: Flat-panel cone-beam computed tomography (FP-CBCT) has recently been introduced as a clinical feature in neuroangiography radiographic C-arm systems. OBJECTIVE: To introduce a method of positioning a surgical tool such as a needle or ablation probe within a target specified by intraoperative FP-CBCT scanning. METHODS: Two human cadaver and 2 porcine cadaver heads were injected with a mixture of silicone and contrast agent to simulate a contrast-enhanced tumor. Preoperative imaging was performed using a standard 1.5-T magnetic resonance imaging scanner. Intraoperative imaging was used to define the needle trajectory on a GE Innova 4100 flat panel-based neuroangiography C-arm system. RESULTS: Using a combination of FP-CBCT and fluoroscopy, a needle was successfully positioned within each of the simulated contrast-enhanced tumors, as verified by subsequent FP-CBCT scans. CONCLUSIONS: This proof-of-concept study demonstrates the potential utility of combining FP-CBCT scanning with fluoroscopy to position surgical tools when stereotactic devices and image-guided surgery systems are not available. However, further work is required to fully characterize the precision and accuracy of the method in a variety of realistic surgical sites.

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