33 results on '"Hassel F"'
Search Results
2. Recurrent fully convolutional network for 3D brain tumor segmentation
- Author
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Hassel, F. van, Hassel, F. van, Hassel, F. van, and Hassel, F. van
- Published
- 2020
3. Case-matched radiological and clinical outcome evaluation of interlaminar versus microsurgical decompression of lumbar spinal stenosis
- Author
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Saravi, B, Lang, G, Ülkümen, S, Südkamp, N, Hassel, F, Saravi, B, Lang, G, Ülkümen, S, Südkamp, N, and Hassel, F
- Published
- 2021
4. Prospektive, multizentrische Beobachtungsstudie über die Verwendung von Wirbelkörperimplantaten zur Versorgung traumatischer Wirbelkompressionsfrakturen – Ergebnisse nach 12 Monaten
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Hassel, F, Noriega, D, Francaviglia, N, Renaud, C, Ould Slimane, M, Queinnec, S, Ekkerlein, H, and Maestretti, G
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ddc: 610 ,SpineJack ,minimalinvasiv ,610 Medical sciences ,Medicine ,Wirbelkörperfraktur ,Trauma - Abstract
Fragestellung: Die minimalinvasive Versorgung von Wirbelkompressionsfrakturen (WKF) mit Wirbelkörperimplantaten könnte eine Lösung darstellen für das Erzielen einer anatomisch korrekten Frakturreposition und ein geringeres Aufkommen an Komplikationen als bei invasiveren Verfahren.[zum vollständigen Text gelangen Sie über die oben angegebene URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2015)
- Published
- 2015
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5. Die Versorgung der lumbalen Instabilität an der osteoporotischen Wirbelsäule mit speziellen zementaugmentierten Pedikelschrauben
- Author
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Beck, J., Hassel, F., Schorer, U., and Pfeiffer, M.
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ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Fragestellung: Die Verwendung von Pedikelschraubensystemen zur Durchführung einer Fusion mit Spondylodese stellt im Lumbalbereich seit Jahren den Goldstandard dar. Problematisch zeigte sich jedoch die Versorgung von Instabilitäten bei ausgeprägter Osteoporose der LWS mit entsprechenden[for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie; 73. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 95. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 50. Tagung des Berufsverbandes der Fachärzte für Orthopädie
- Published
- 2009
6. Die Distraktionsarthrodese des Kreuzdarmbeingelenkes - eine neue Lösung für ein altes Problem
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Fuchs, V, Stark, J, Hassel, F, Fuchs, V, Stark, J, and Hassel, F
- Published
- 2013
7. Neue Lösung für ein altes Problem - Distraktionsarthrodese des Iliosakralgelenks
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Hassel, F, Beck, J, Steinitz, A, Hassel, F, Beck, J, and Steinitz, A
- Published
- 2012
8. Die Versorgung der lumbalen Instabilität an der osteoporotischen Wirbelsäule mit speziellen zementaugmentierten Pedikelschrauben
- Author
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Beck, J, Hassel, F, Schorer, U, Pfeiffer, M, Beck, J, Hassel, F, Schorer, U, and Pfeiffer, M
- Published
- 2009
9. Joint PDFs of Scalar Quantities in Turbulent Diffusion Flames by Raman and Rayleigh Scattering
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Hassel, F., primary, Hundhausen, A., additional, Klos, Th., additional, Sprenzel, U., additional, and Bockhorn, H., additional
- Published
- 1993
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10. Immunoassay of serum conjugates of cholic acid in cystic fibrosis.
- Author
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Davidson, G P, Corey, M, Morad-Hassel, F, Sondheimer, J M, Crozier, D, and Forstner, G G
- Abstract
Pre- and post-prandial serum conjugates of cholic acid (SCCA) were measured by radioimmunoassay (RIA) in 83 patients with cystic fibrosis (CF), 14 of whom did not have steatorrhoea, and in 25 controls. Of the CF patients with steatorrhoea, 38% had fasting SCCA levels greater than 3 standard deviations above mean fasting control values, whereas no CF patient without steatorrhoea had elevated fasting SCCA levels. Steatorrhoeic patients with palpable livers had higher pre- and post-prandial SCCA levels. Post-prandial SCCA levels failed to discriminate between control and CF groups however. Other serum tests of liver function, including the aspartate amino transferase, alkaline phosphatase, albumin, gamma globulin, and albumin : globulin ratio, failed to correlate with the SCCA. Changes in serum protein constituents correlated strongly with pulmonary dysfunction. The results suggest that elevation of fasting SCCA levels in CF patients is a more sensitive indicator of liver dysfunction than other tests and is a better discriminator than post-prandial SCCA levels between normal and abnormal liver function. The test is recommended for early detection of liver dysfunction in CF patients. [ABSTRACT FROM PUBLISHER]
- Published
- 1980
11. Perspectieven inzake het Vlaams politiek-administratief systeem
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Van Hassel, F., primary
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- 1981
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12. Iatrogenic hyperuricemia in children with cystic fibrosis
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Davidson, G.P., primary, Hassel, F. Morad, additional, Crozier, D., additional, Corey, M., additional, and Forstner, G.G., additional
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- 1978
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13. Multimodal artificial intelligence-based pathogenomics improves survival prediction in oral squamous cell carcinoma.
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Vollmer A, Hartmann S, Vollmer M, Shavlokhova V, Brands RC, Kübler A, Wollborn J, Hassel F, Couillard-Despres S, Lang G, and Saravi B
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- Humans, Squamous Cell Carcinoma of Head and Neck genetics, Artificial Intelligence, Carcinoma, Squamous Cell genetics, Mouth Neoplasms genetics, Head and Neck Neoplasms
- Abstract
In this study, we aimed to develop a novel prognostic algorithm for oral squamous cell carcinoma (OSCC) using a combination of pathogenomics and AI-based techniques. We collected comprehensive clinical, genomic, and pathology data from a cohort of OSCC patients in the TCGA dataset and used machine learning and deep learning algorithms to identify relevant features that are predictive of survival outcomes. Our analyses included 406 OSCC patients. Initial analyses involved gene expression analyses, principal component analyses, gene enrichment analyses, and feature importance analyses. These insights were foundational for subsequent model development. Furthermore, we applied five machine learning/deep learning algorithms (Random Survival Forest, Gradient Boosting Survival Analysis, Cox PH, Fast Survival SVM, and DeepSurv) for survival prediction. Our initial analyses revealed relevant gene expression variations and biological pathways, laying the groundwork for robust feature selection in model building. The results showed that the multimodal model outperformed the unimodal models across all methods, with c-index values of 0.722 for RSF, 0.633 for GBSA, 0.625 for FastSVM, 0.633 for CoxPH, and 0.515 for DeepSurv. When considering only important features, the multimodal model continued to outperform the unimodal models, with c-index values of 0.834 for RSF, 0.747 for GBSA, 0.718 for FastSVM, 0.742 for CoxPH, and 0.635 for DeepSurv. Our results demonstrate the potential of pathogenomics and AI-based techniques in improving the accuracy of prognostic prediction in OSCC, which may ultimately aid in the development of personalized treatment strategies for patients with this devastating disease., (© 2024. The Author(s).)
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- 2024
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14. Bringing Back a Scientific and Updated Approach to Wildlife Conservation: A Response. Reply to Beltrán, J.F.; Rodríguez-Rodríguez, E.J. Relying on Incomplete Information Can Lead to the Wrong Conclusions. Comment on "van Hassel, F.; Bovenkerk, B. How Should We Help Wild Animals Cope with Climate Change? The Case of the Iberian Lynx. Animals 2023, 13 , 453".
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van Hassel F and Bovenkerk B
- Abstract
We are pleased that our paper on the need to extend climate justice to animals [...].
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- 2024
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15. Artificial intelligence-based analysis of associations between learning curve and clinical outcomes in endoscopic and microsurgical lumbar decompression surgery.
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Saravi B, Zink A, Ülkümen S, Couillard-Despres S, Lang G, and Hassel F
- Abstract
Purpose: A common spine surgery procedure involves decompression of the lumbar spine. The impact of the surgeon's learning curve on relevant clinical outcomes is currently not well examined in the literature. A variety of machine learning algorithms have been investigated in this study to determine how a surgeon's learning curve and other clinical parameters will influence prolonged lengths of stay (LOS), extended operating times (OT), and complications, as well as whether these clinical parameters can be reliably predicted., Methods: A retrospective monocentric cohort study of patients with lumbar spinal stenosis treated with microsurgical (MSD) and full-endoscopic (FED) decompression was conducted. The study included 206 patients with lumbar spinal stenosis who underwent FED (63; 30.6%) and MSD (118; 57.3%). Prolonged LOS and OT were defined as those exceeding the 75th percentile of the cohort. Furthermore, complications were assessed as a dependent variable. Using unsupervised learning, clusters were identified in the data, which helped distinguish between the early learning curve (ELC) and the late learning curve (LLC). From 15 algorithms, the top five algorithms that best fit the data were selected for each prediction task. We calculated the accuracy of prediction (Acc) and the area under the curve (AUC). The most significant predictors were determined using a feature importance analysis., Results: For the FED group, the median number of surgeries with case surgery type at the time of surgery was 72 in the ELC group and 274 in the LLC group. FED patients did not significantly differ in outcome variables (LOS, OT, complication rate) between the ELC and LLC group. The random forest model demonstrated the highest mean accuracy and AUC across all folds for each classification task. For OT, it achieved an accuracy of 76.08% and an AUC of 0.89. For LOS, the model reached an accuracy of 83.83% and an AUC of 0.91. Lastly, in predicting complications, the random forest model attained the highest accuracy of 89.90% and an AUC of 0.94. Feature importance analysis indicated that LOS, OT, and complications were more significantly affected by patient characteristics than the surgical technique (FED versus MSD) or the surgeon's learning curve., Conclusions: A median of 72 cases of FED surgeries led to comparable clinical outcomes in the early learning curve phase compared to experienced surgeons. These outcomes seem to be more significantly affected by patient characteristics than the learning curve or the surgical technique. Several study variables, including the learning curve, can be used to predict whether lumbar decompression surgery will result in an increased LOS, OT, or complications. To introduce the provided prediction tools into clinics, the algorithms need to be implemented into open-source software and externally validated through large-scale randomized controlled trials., (© 2023. The Author(s).)
- Published
- 2023
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16. Synthetic 3D Spinal Vertebrae Reconstruction from Biplanar X-rays Utilizing Generative Adversarial Networks.
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Saravi B, Guzel HE, Zink A, Ülkümen S, Couillard-Despres S, Wollborn J, Lang G, and Hassel F
- Abstract
Computed tomography (CT) offers detailed insights into the internal anatomy of patients, particularly for spinal vertebrae examination. However, CT scans are associated with higher radiation exposure and cost compared to conventional X-ray imaging. In this study, we applied a Generative Adversarial Network (GAN) framework to reconstruct 3D spinal vertebrae structures from synthetic biplanar X-ray images, specifically focusing on anterior and lateral views. The synthetic X-ray images were generated using the DRRGenerator module in 3D Slicer by incorporating segmentations of spinal vertebrae in CT scans for the region of interest. This approach leverages a novel feature fusion technique based on X2CT-GAN to combine information from both views and employs a combination of mean squared error (MSE) loss and adversarial loss to train the generator, resulting in high-quality synthetic 3D spinal vertebrae CTs. A total of n = 440 CT data were processed. We evaluated the performance of our model using multiple metrics, including mean absolute error (MAE) (for each slice of the 3D volume (MAE0) and for the entire 3D volume (MAE)), cosine similarity, peak signal-to-noise ratio (PSNR), 3D peak signal-to-noise ratio (PSNR-3D), and structural similarity index (SSIM). The average PSNR was 28.394 dB, PSNR-3D was 27.432, SSIM was 0.468, cosine similarity was 0.484, MAE0 was 0.034, and MAE was 85.359. The results demonstrated the effectiveness of this approach in reconstructing 3D spinal vertebrae structures from biplanar X-rays, although some limitations in accurately capturing the fine bone structures and maintaining the precise morphology of the vertebrae were present. This technique has the potential to enhance the diagnostic capabilities of low-cost X-ray machines while reducing radiation exposure and cost associated with CT scans, paving the way for future applications in spinal imaging and diagnosis.
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- 2023
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17. Clinical and radiomics feature-based outcome analysis in lumbar disc herniation surgery.
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Saravi B, Zink A, Ülkümen S, Couillard-Despres S, Wollborn J, Lang G, and Hassel F
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- Humans, Artificial Intelligence, Treatment Outcome, Diskectomy methods, Lumbar Vertebrae diagnostic imaging, Lumbar Vertebrae surgery, Lumbar Vertebrae pathology, Retrospective Studies, Intervertebral Disc Displacement diagnostic imaging, Intervertebral Disc Displacement surgery, Intervertebral Disc Displacement complications, Low Back Pain diagnostic imaging, Low Back Pain etiology, Low Back Pain surgery
- Abstract
Background: Low back pain is a widely prevalent symptom and the foremost cause of disability on a global scale. Although various degenerative imaging findings observed on magnetic resonance imaging (MRI) have been linked to low back pain and disc herniation, none of them can be considered pathognomonic for this condition, given the high prevalence of abnormal findings in asymptomatic individuals. Nevertheless, there is a lack of knowledge regarding whether radiomics features in MRI images combined with clinical features can be useful for prediction modeling of treatment success. The objective of this study was to explore the potential of radiomics feature analysis combined with clinical features and artificial intelligence-based techniques (machine learning/deep learning) in identifying MRI predictors for the prediction of outcomes after lumbar disc herniation surgery., Methods: We included n = 172 patients who underwent discectomy due to disc herniation with preoperative T2-weighted MRI examinations. Extracted clinical features included sex, age, alcohol and nicotine consumption, insurance type, hospital length of stay (LOS), complications, operation time, ASA score, preoperative CRP, surgical technique (microsurgical versus full-endoscopic), and information regarding the experience of the performing surgeon (years of experience with the surgical technique and the number of surgeries performed at the time of surgery). The present study employed a semiautomatic region-growing volumetric segmentation algorithm to segment herniated discs. In addition, 3D-radiomics features, which characterize phenotypic differences based on intensity, shape, and texture, were extracted from the computed magnetic resonance imaging (MRI) images. Selected features identified by feature importance analyses were utilized for both machine learning and deep learning models (n = 17 models)., Results: The mean accuracy over all models for training and testing in the combined feature set was 93.31 ± 4.96 and 88.17 ± 2.58. The mean accuracy for training and testing in the clinical feature set was 91.28 ± 4.56 and 87.69 ± 3.62., Conclusions: Our results suggest a minimal but detectable improvement in predictive tasks when radiomics features are included. However, the extent of this advantage should be considered with caution, emphasizing the potential of exploring multimodal data inputs in future predictive modeling., (© 2023. BioMed Central Ltd., part of Springer Nature.)
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- 2023
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18. Radiation exposure for pedicle screw placement with three different navigation system and imaging combinations in a sawbone model.
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Beisemann N, Gierse J, Mandelka E, Hassel F, Grützner PA, Franke J, and Vetter SY
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- Humans, Diagnostic Imaging, Analysis of Variance, Heart Rate, Pedicle Screws, Radiation Exposure prevention & control
- Abstract
Background: Studies have shown that pedicle screw placement using navigation can potentially reduce radiation exposure of surgical personnel compared to conventional methods. Spinal navigation is based on an interaction of a navigation software and 3D imaging. The 3D image data can be acquired using different imaging modalities such as iCT and CBCT. These imaging modalities vary regarding acquisition technique and field of view. The current literature varies greatly in study design, in form of dose registration, as well as navigation systems and imaging modalities analyzed. Therefore, the aim of this study was a standardized comparison of three navigation and imaging system combinations in an experimental setting in an artificial spine model., Methods: In this experimental study dorsal instrumentation of the thoracolumbar spine was performed using three imaging/navigation system combinations. The system combinations applied were the iCT/Curve, cCBCT/Pulse and oCBCT/StealthStation. Referencing scans were obtained with each imaging modality and served as basis for the respective navigation system. In each group 10 artificial spine models received bilateral dorsal instrumentation from T11-S1. 2 referencing and control scans were acquired with the CBCTs, since their field of view could only depict up to five vertebrae in one scan. The field of view of the iCT enabled the depiction of T11-S1 in one scan. After instrumentation the region of interest was scanned again for evaluation of the screw position, therefore only one referencing and one control scan were obtained. Two dose meters were installed in a spine bed ventral of L1 and S1. The dose measurements in each location and in total were analyzed for each system combination. Time demand regarding screw placement was also assessed for all system combinations., Results: The mean radiation dose in the iCT group measured 1,6 ± 1,1 mGy. In the cCBCT group the mean was 3,6 ± 0,3 mGy and in the oCBCT group 10,3 ± 5,7 mGy were measured. The analysis of variance (ANOVA) showed a significant (p < 0.0001) difference between the three groups. The multiple comparisions by the Kruskall-Wallis test showed no significant difference for the comparison of iCT and cCBCT (p
1 = 0,13). Significant differences were found for the direct comparison of iCT and oCBCT (p2 < 0,0001), as well as cCBCT and oCBCT (p3 = 0,02). Statistical analysis showed that significantly (iCT vs. oCBCT p = 0,0434; cCBCT vs. oCBCT p = 0,0083) less time was needed for oCBCT based navigated pedicle screw placement compared to the other system combinations (iCT vs. cCBCT p = 0,871)., Conclusion: Under standardized conditions oCBCT navigation demanded twice as much radiation as the cCBCT for the same number of scans, while the radiation exposure measured for the iCT and cCBCT for one scan was comparable. Yet, time effort was significantly less for oCBCT based navigation. However, for transferability into clinical practice additional studies should follow evaluating parameters regarding feasibility and clinical outcome under standardized conditions., (© 2023. BioMed Central Ltd., part of Springer Nature.)- Published
- 2023
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19. Automated Detection and Measurement of Dural Sack Cross-Sectional Area in Lumbar Spine MRI Using Deep Learning.
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Saravi B, Zink A, Ülkümen S, Couillard-Despres S, Wollborn J, Lang G, and Hassel F
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Lumbar spine magnetic resonance imaging (MRI) is a critical diagnostic tool for the assessment of various spinal pathologies, including degenerative disc disease, spinal stenosis, and spondylolisthesis. The accurate identification and quantification of the dural sack cross-sectional area are essential for the evaluation of these conditions. Current manual measurement methods are time-consuming and prone to inter-observer variability. Our study developed and validated deep learning models, specifically U-Net, Attention U-Net, and MultiResUNet, for the automated detection and measurement of the dural sack area in lumbar spine MRI, using a dataset of 515 patients with symptomatic back pain and externally validating the results based on 50 patient scans. The U-Net model achieved an accuracy of 0.9990 and 0.9987 on the initial and external validation datasets, respectively. The Attention U-Net model reported an accuracy of 0.9992 and 0.9989, while the MultiResUNet model displayed a remarkable accuracy of 0.9996 and 0.9995, respectively. All models showed promising precision, recall, and F1-score metrics, along with reduced mean absolute errors compared to the ground truth manual method. In conclusion, our study demonstrates the potential of these deep learning models for the automated detection and measurement of the dural sack cross-sectional area in lumbar spine MRI. The proposed models achieve high-performance metrics in both the initial and external validation datasets, indicating their potential utility as valuable clinical tools for the evaluation of lumbar spine pathologies. Future studies with larger sample sizes and multicenter data are warranted to validate the generalizability of the model further and to explore the potential integration of this approach into routine clinical practice.
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- 2023
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20. Case-matched radiological and clinical outcome evaluation of interlaminar versus microsurgical decompression of lumbar spinal stenosis.
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Saravi B, Ülkümen S, Lang G, Couillard-Després S, and Hassel F
- Subjects
- Humans, Decompression, Surgical methods, Prospective Studies, Lumbar Vertebrae diagnostic imaging, Lumbar Vertebrae surgery, Back Pain surgery, Treatment Outcome, Retrospective Studies, Spinal Stenosis diagnostic imaging, Spinal Stenosis surgery
- Abstract
Purpose: Endoscopic spine surgery is a globally expanding technique advocated as less invasive for spinal stenosis treatment compared to the microsurgical approach. However, evidence on the efficiency of interlaminar full-endoscopic decompression (FED) vs. conventional microsurgical decompression (MSD) in patients with lumbar spinal stenosis is still scarce. We conducted a case-matched comparison for treatment success with consideration of clinical, laboratory, and radiologic predictors., Methods: We included 88 consecutive patients (FED: 36/88, 40.9%; MSD: 52/88, 59.1%) presenting with lumbar central spinal stenosis. Surgery-related (operation time, complications, length of stay (LOS), American Society of Anesthesiologists physical status (ASA) score, C-reactive protein (CRP), white blood cell count, side of approach (unilateral/bilateral), patient-related outcome measures (PROMs) (Oswestry disability index (ODI), numeric rating scale of pain (NRS; leg-, back pain), EuroQol questionnaire (eQ-5D), core outcome measures index (COMI)), and radiological (dural sack cross-sectional area, Schizas score (SC), left and right lateral recess heights, and facet angles, respectively) parameters were extracted at different time points up to 1-year follow-up. The relationship of PROMs was analyzed using Spearman's rank correlation. Surgery-related outcome parameters were correlated with patient-centered and radiological outcomes utilizing a regression model to determine predictors for propensity score matching., Results: Complication (most often residual sensorimotor deficits and restenosis due to hematoma) rates were higher in the FED (33.3%) than MSD (13.5%) group (p < 0.05), while all complications in the FED group were observed within the first 20 FED patients. Operation time was higher in the FED, whereas LOS was higher in the MSD group. Age, SC, CRP revealed significant associations with PROMs. We did not observe significant differences in the endoscopic vs. microsurgical group in PROMs. The correlation between ODI and COMI was significantly high, and both were inversely correlated with eQ-5D, whereas the correlations of these PROMs with NRS findings were less pronounced., Conclusions: Endoscopic treatment of lumbar spinal stenosis was similarly successful as the conventional microsurgical approach. Although FED was associated with higher complication rates in our single-center study experience, the distribution of complications indicated surgical learning curves to be the main factor of these findings. Future long-term prospective studies considering the surgical learning curve are warranted for reliable comparisons of these techniques., (© 2023. The Author(s).)
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- 2023
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21. How Should We Help Wild Animals Cope with Climate Change? The Case of the Iberian Lynx.
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van Hassel F and Bovenkerk B
- Abstract
Climate change and related shifts in weather conditions result in massive biodiversity declines and severe animal suffering. This article explores the measures that can be taken to decrease animal suffering and prevent species from going extinct. Taking the Iberian lynx as a case study, we assess the extent to which it is beneficial for animal welfare and species conservation to do nothing or reduce other threats, provide food or shelter, relocate the species via assisted migration, or bring the population into captivity. We argue that, given the Iberian lynx's non-invasive characteristics, assisted migration may be the best way to protect the species while ensuring animal welfare and protecting wildness and other ecosystem values.
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- 2023
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22. Full-endoscopic versus conventional microsurgical therapy of lumbar disc herniation: a prospective, controlled, single-center, comprehensive cohort trial (FEMT-LDH trial).
- Author
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Saravi B, Ülkümen S, Couillard-Despres S, Hassel F, and Lang G
- Subjects
- Humans, Prospective Studies, Cohort Studies, Intervertebral Disc Displacement surgery
- Abstract
Background: Lumbar disc herniation is one of the leading causes of chronic low back pain. Surgery remains the therapy of choice when conservative approaches fail. Full-endoscopic approaches represent a promising alternative to the well-established microsurgical technique. However, high-grade evidence comparing these techniques is still scarce., Methods: Patients presenting with lumbar disc herniation will be included. The intervention group will obtain full-endoscopic disc decompression, whereas the control group will be treated by microsurgical disc decompression. We will apply a comprehensive cohort study design involving a randomized and a prospective non-randomized study arm. Patients who do not consent to be randomized will be assigned to the non-randomized arm. The primary outcome will be the Oswestry Disability Index (ODI). Secondary outcomes involve the visual analog scale (VAS) of pain and the SF-36 health questionnaire. Furthermore, clinical characteristics including duration of hospital stay, operation time, and complications as well as laboratory markers, such as C-reactive protein, white blood cell counts, and interleukin 6 will be determined and compared., Discussion: This study will significantly contribute to the current evidence available in the literature by evaluating the outcome of the full-endoscopic technique against the gold standard for lumbar disc herniation in a clinically relevant study setup. Additionally, the study design allows us to include patients not willing to be randomized in a prospective parallel study arm and to evaluate the impact of randomization on outcomes and include. The results could help to improve the future therapy in patients suffering from lumbar disc herniation., Trial Registration: This study was prospectively registered in The German Clinical Trials Register (DRKS), a German WHO primary registry, under the registration number: DRKS00025786. Registered on July 7, 2021., (© 2022. The Author(s).)
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- 2022
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23. Comparison of three imaging and navigation systems regarding accuracy of pedicle screw placement in a sawbone model.
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Beisemann N, Gierse J, Mandelka E, Hassel F, Grützner PA, Franke J, and Vetter SY
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- Fluoroscopy methods, Reproducibility of Results, Spine surgery, Pedicle Screws, Spinal Fusion methods, Surgery, Computer-Assisted methods
- Abstract
3D-navigated pedicle screw placement is increasingly performed as the accuracy has been shown to be considerably higher compared to fluoroscopy-guidance. While different imaging and navigation devices can be used, there are few studies comparing these under similar conditions. Thus, the objective of this study was to compare the accuracy of two combinations most used in the literature for spinal navigation and a recently approved combination of imaging device and navigation system. With each combination of imaging system and navigation interface, 160 navigated screws were placed percutaneously in spine levels T11-S1 in ten artificial spine models. 470 screws were included in the final evaluation. Two blinded observers classified screw placement according to the Gertzbein Robbins grading system. Grades A and B were considered acceptable and Grades C-E unacceptable. Weighted kappa was used to calculate reliability between the observers. Mean accuracy was 94.9% (149/157) for iCT/Curve, 97.5% (154/158) for C-arm CBCT/Pulse and 89.0% for CBCT/StealthStation (138/155). The differences between the different combinations were not statistically significant except for the comparison of C-arm CBCT/Pulse and CBCT/StealthStation (p = 0.003). Relevant perforations of the medial pedicle wall were only seen in the CBCT group. Weighted interrater reliability was found to be 0.896 for iCT, 0.424 for C-arm CBCT and 0.709 for CBCT. Under quasi-identical conditions, higher screw accuracy was achieved with the combinations iCT/Curve and C-arm CBCT/Pulse compared with CBCT/StealthStation. However, the exact reasons for the difference in accuracy remain unclear. Weighted interrater reliability for Gertzbein Robbins grading was moderate for C-arm CBCT, substantial for CBCT and almost perfect for iCT., (© 2022. The Author(s).)
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- 2022
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24. Performance of Artificial Intelligence-Based Algorithms to Predict Prolonged Length of Stay after Lumbar Decompression Surgery.
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Saravi B, Zink A, Ülkümen S, Couillard-Despres S, Hassel F, and Lang G
- Abstract
Background: Decompression of the lumbar spine is one of the most common procedures performed in spine surgery. Hospital length of stay (LOS) is a clinically relevant metric used to assess surgical success, patient outcomes, and socioeconomic impact. This study aimed to investigate a variety of machine learning and deep learning algorithms to reliably predict whether a patient undergoing decompression of lumbar spinal stenosis will experience a prolonged LOS., Methods: Patients undergoing treatment for lumbar spinal stenosis with microsurgical and full-endoscopic decompression were selected within this retrospective monocentric cohort study. Prolonged LOS was defined as an LOS greater than or equal to the 75th percentile of the cohort (normal versus prolonged stay; binary classification task). Unsupervised learning with K-means clustering was used to find clusters in the data. Hospital stay classes were predicted with logistic regression, RandomForest classifier, stochastic gradient descent (SGD) classifier, K-nearest neighbors, Decision Tree classifier, Gaussian Naive Bayes (GaussianNB), support vector machines (SVM), a custom-made convolutional neural network (CNN), multilayer perceptron artificial neural network (MLP), and radial basis function neural network (RBNN) in Python. Prediction accuracy and area under the curve (AUC) were calculated. Feature importance analysis was utilized to find the most important predictors. Further, we developed a decision tree based on the Chi-square automatic interaction detection (CHAID) algorithm to investigate cut-offs of predictors for clinical decision-making., Results: 236 patients and 14 feature variables were included. K-means clustering separated data into two clusters distinguishing the data into two patient risk characteristic groups. The algorithms reached AUCs between 67.5% and 87.3% for the classification of LOS classes. Feature importance analysis of deep learning algorithms indicated that operation time was the most important feature in predicting LOS. A decision tree based on CHAID could predict 84.7% of the cases., Conclusions: Machine learning and deep learning algorithms can predict whether patients will experience an increased LOS following lumbar decompression surgery. Therefore, medical resources can be more appropriately allocated to patients who are at risk of prolonged LOS.
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- 2022
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25. One-Year Clinical Outcomes of Minimal-Invasive Dorsal Percutaneous Fixation of Thoracolumbar Spine Fractures.
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Saravi B, Ülkümen S, Couillard-Despres S, Lang G, and Hassel F
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- Aged, Aged, 80 and over, Fracture Fixation, Internal, Humans, Lumbar Vertebrae injuries, Lumbar Vertebrae surgery, Middle Aged, Thoracic Vertebrae injuries, Thoracic Vertebrae surgery, Treatment Outcome, Fractures, Bone, Spinal Fractures surgery
- Abstract
Introduction: Minimal-invasive instrumentation techniques have become a workhorse in spine surgery and require constant clinical evaluations. We sought to analyze patient-reported outcome measures (PROMs) and clinicopathological characteristics of thoracolumbar fracture stabilizations utilizing a minimal-invasive percutaneous dorsal screw-rod system. Methods: We included all patients with thoracolumbar spine fractures who underwent minimal-invasive percutaneous spine stabilization in our clinics since inception and who have at least 1 year of follow-up data. Clinical characteristics (length of hospital stay (LOS), operation time (OT), and complications), PROMs (preoperative (pre-op), 3-weeks postoperative (post-op), 1-year postoperative: eq5D, COMI, ODI, NRS back pain), and laboratory markers (leucocytes, c-reactive protein (CRP)) were analyzed, finding significant associations between these study variables and PROMs. Results: A total of 68 patients (m: 45.6%; f: 54.4%; mean age: 76.9 ± 13.9) were included. The most common fracture types according to the AO classification were A3 (40.3%) and A4 (40.3%), followed by B2 (7.46%) and B1 (5.97%). The Median American Society of Anesthesiologists (ASA) score was 3 (range: 1−4). Stabilized levels ranged from TH4 to L5 (mean number of targeted levels: 4.25 ± 1.4), with TH10-L2 (12/68) and TH11-L3 (11/68) being the most frequent site of surgery. Mean OT and LOS were 92.2 ± 28.2 min and 14.3 ± 6.9 days, respectively. We observed 9/68 complications (13.2%), mostly involving screw misalignments and loosening. CRP increased from 24.9 ± 33.3 pre-op to 34.8 ± 29.9 post-op (p < 0.001), whereas leucocyte counts remained stable. All PROMs showed a marked significant improvement for both 3-week and 1-year evaluations compared to the preoperative situation. Interestingly, we did not find an impact of OT, LOS, lab markers, complications, and other clinical characteristics on PROMs. Notably, a higher number of stabilized levels did not affect PROMs. Conclusions: Minimal-invasive stabilization of thoracolumbar fractures utilizing a dorsal percutaneous approach resulted in significant PROM outcome improvements, although we observed a complication rate of 13.2% for up to 1 year of follow-up. PROMs were not significantly associated with clinicopathological characteristics, technique-related variables, or the number of targeted levels.
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- 2022
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26. Artificial Intelligence-Driven Prediction Modeling and Decision Making in Spine Surgery Using Hybrid Machine Learning Models.
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Saravi B, Hassel F, Ülkümen S, Zink A, Shavlokhova V, Couillard-Despres S, Boeker M, Obid P, and Lang GM
- Abstract
Healthcare systems worldwide generate vast amounts of data from many different sources. Although of high complexity for a human being, it is essential to determine the patterns and minor variations in the genomic, radiological, laboratory, or clinical data that reliably differentiate phenotypes or allow high predictive accuracy in health-related tasks. Convolutional neural networks (CNN) are increasingly applied to image data for various tasks. Its use for non-imaging data becomes feasible through different modern machine learning techniques, converting non-imaging data into images before inputting them into the CNN model. Considering also that healthcare providers do not solely use one data modality for their decisions, this approach opens the door for multi-input/mixed data models which use a combination of patient information, such as genomic, radiological, and clinical data, to train a hybrid deep learning model. Thus, this reflects the main characteristic of artificial intelligence: simulating natural human behavior. The present review focuses on key advances in machine and deep learning, allowing for multi-perspective pattern recognition across the entire information set of patients in spine surgery. This is the first review of artificial intelligence focusing on hybrid models for deep learning applications in spine surgery, to the best of our knowledge. This is especially interesting as future tools are unlikely to use solely one data modality. The techniques discussed could become important in establishing a new approach to decision-making in spine surgery based on three fundamental pillars: (1) patient-specific, (2) artificial intelligence-driven, (3) integrating multimodal data. The findings reveal promising research that already took place to develop multi-input mixed-data hybrid decision-supporting models. Their implementation in spine surgery may hence be only a matter of time.
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- 2022
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27. Endoscopic Techniques for Lumbar Interbody Fusion: Principles and Context.
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Zheng B, Shaaya E, Feler J, Leary OP, Hagan MJ, Bajaj A, Fridley JS, Hassel F, Gardocki R, Grau RC, Lewandrowski KU, and Telfeian AE
- Subjects
- Endoscopy methods, Lumbosacral Region, Minimally Invasive Surgical Procedures methods, Lumbar Vertebrae diagnostic imaging, Lumbar Vertebrae surgery, Spinal Fusion methods
- Abstract
Endoscopic techniques in spine surgery are rapidly evolving, with operations becoming progressively safer and less invasive. Lumbar interbody fusion (LIF) procedures comprise many spine procedures that have benefited from endoscopic assistance and minimally invasive approaches. Though considerable variation exists within endoscopic LIF, similar principles and techniques are common to all types. Nonetheless, innovations continually emerge, requiring trainees and experienced surgeons to maintain familiarity with the domain and its possibilities. We present two illustrative cases of endoscopic transforaminal lumbar interbody fusion with a comprehensive literature review of the different approaches to endoscopic LIF procedures., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 Bryan Zheng et al.)
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- 2022
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28. A prospective, international, randomized, noninferiority study comparing an titanium implantable vertebral augmentation device versus balloon kyphoplasty in the reduction of vertebral compression fractures (SAKOS study).
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Noriega D, Marcia S, Theumann N, Blondel B, Simon A, Hassel F, Maestretti G, Petit A, Weidle PA, Gonzalez AM, Kaya JM, Touta A, Fuentes S, and Pflugmacher R
- Subjects
- Humans, Prospective Studies, Titanium, Fractures, Compression surgery, Kyphoplasty adverse effects, Osteoporotic Fractures, Spinal Fractures surgery
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- 2020
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29. A prospective, international, randomized, noninferiority study comparing an implantable titanium vertebral augmentation device versus balloon kyphoplasty in the reduction of vertebral compression fractures (SAKOS study).
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Noriega D, Marcia S, Theumann N, Blondel B, Simon A, Hassel F, Maestretti G, Petit A, Weidle PA, Mandly AG, Kaya JM, Touta A, Fuentes S, and Pflugmacher R
- Subjects
- Aged, Aged, 80 and over, Bone Cements therapeutic use, Equivalence Trials as Topic, Female, Fractures, Compression diagnostic imaging, Humans, Infant, Male, Middle Aged, Osteoporotic Fractures diagnostic imaging, Pain etiology, Pain surgery, Prospective Studies, Quality of Life, Radiography, Spinal Fractures diagnostic imaging, Titanium, Treatment Outcome, Fracture Fixation, Internal instrumentation, Fractures, Compression surgery, Internal Fixators, Kyphoplasty methods, Osteoporotic Fractures surgery, Spinal Fractures surgery
- Abstract
Background Context: Balloon kyphoplasty (BKP) is a commonly performed vertebral augmentation procedure for painful osteoporotic vertebral compression fractures (OVCFs)., Objective: This study aimed to support a non-inferiority finding for the use of a titanium implantable vertebral augmentation device (TIVAD) compared to BKP., Study Design: Prospective, parallel group, controlled comparative randomized study., Patient Sample: Patients who presented with one or two painful OVCFs located between T7 and L4 aged <3 months, failed conservative treatment, and had an Oswestry Disability Index (ODI) score ≥30/100 were eligible for the study., Outcome Measures: The primary composite endpoint was defined as: reduction in VCF fracture-related pain at 12 months from baseline and maintenance or functional improvement (ODI) at 12 months from baseline, and absence of device-related adverse event or surgical reintervention. If the primary composite endpoint was successful, a fourth component (absence of adjacent level fracture) was added for analysis. If the analysis of this additional composite endpoint was successful, then midline target height restoration at 6 and 12 months was assessed. Secondary clinical outcomes included back pain intensity, ODI score, EQ-5D index score (range 0=death to 1=full health) and EQ-VAS score (range 0-100)., Methods: Patients were recruited in 13 hospitals across 5 countries and were randomly assigned (1:1) to either TIVAD or BKP with electronic randomization as described in the protocol. A total of 152 patients with OVCFs were initially randomized. Eleven patients were excluded (six met exclusion criteria, one with evidence of tumor, and four patients had T score out of requested range). Anterior vertebral body height ratio, midline vertebral body height ratio, and Cobb angle were measured preoperatively and postoperatively by an independent imaging core lab. Adjacent and subsequent fractures and safety parameters were recorded throughout the study. Cement extravasation was evaluated on X-rays. All patients were followed at screening at 5 days, 1 month, 6 months, and 12 months postoperatively. This study was supported by Vexim SA. Seven authors received study-specific support less than $10,000 per year and seven authors received no study-specific support., Results: Among the 141 patients (78.7% female, mean age 73.3±9.5 years) who underwent surgery (TIVAD=68; BKP=73), 126 patients (89.4%) completed the 12-month follow-up period (TIVAD=61; BKP=65). The analysis of primary endpoint on the ITT population demonstrated non-inferiority of the TIVAD to BKP. The analysis of the additional composite endpoint demonstrated the superiority of TIVAD over BKP (p<0.0001) at 6 months (88.1% vs. 60.9%) and at 12 months (79.7% vs. 59.3%). Midline VB height restoration was more improved for TIVAD than for BKP at 6 months (1.14±2.61 mm vs. 0.31±2.22 mm); p=0.0246) and 12 months after surgery (1.31±2.58 mm vs. 0.10±2.34 mm; p=0.0035). No statistically significant differences were shown between procedures for improvement in functional capacity and quality of life. Pain relief was significantly more marked in the TIVAD group compared to the BKP group at 1 month (p=0.029) and at 6 months (p=0.021) after surgery. No patient required surgical reintervention or retreatment at the treated level. No symptomatic cement leakage was reported. Adverse events were similar for both groups (41.2% in the TIVAD group and 45.2% in the BKP group). The incidence of adjacent fractures was significantly lower after the TIVAD procedure than after BKP (12.9% vs. 27.3%; p=0.043)., Conclusions: Study results demonstrated non-inferiority of the TIVAD to the predicate BKP with an excellent risk/benefit profile for results up to 12 months., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2019
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30. Clinical outcome after the use of a new craniocaudal expandable implant for vertebral compression fracture treatment: one year results from a prospective multicentric study.
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Noriega D, Krüger A, Ardura F, Hansen-Algenstaedt N, Hassel F, Barreau X, and Beyerlein J
- Subjects
- Aged, Aged, 80 and over, Bone Cements therapeutic use, Female, Fractures, Compression epidemiology, Humans, Male, Middle Aged, Pain Measurement, Pain, Postoperative, Prospective Studies, Prosthesis Design, Quality of Life, Spinal Fractures epidemiology, Treatment Outcome, Fractures, Compression surgery, Orthopedic Procedures adverse effects, Orthopedic Procedures instrumentation, Prostheses and Implants, Spinal Fractures surgery
- Abstract
The purpose of this prospective multicentric observational study was to confirm the safety and clinical performance of a craniocaudal expandable implant used in combination with high viscosity PMMA bone cement for the treatment of vertebral compression fractures. Thirty-nine VCFs in 32 patients were treated using the SpineJack minimally invasive surgery protocol. Outcome was determined by using the Visual Analogue Scale for measuring pain, the Oswestry Disability Index for scoring functional capacity, and the self-reporting European Quality of Life scores for the quality of life. Safety was evaluated by reporting all adverse events. The occurrence of cement leakages was assessed by either radiographs or CT scan or both. Statistically significant improvements were found regarding pain, function, and quality of life. The global pain score reduction at 1 year was 80.9% compared to the preoperative situation and the result of the Oswestry Disability Index showed a decrease from 65.0% at baseline to 10.5% at 12 months postoperatively. The cement leakage rate was 30.8%. No device- or surgery-related complications were found. This observational study demonstrates promising and persistent results consisting of immediate and sustained pain relief and durable clinical improvement after the procedure and throughout the 1-year follow-up period.
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- 2015
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31. Clinical Performance and Safety of 108 SpineJack Implantations: 1-Year Results of a Prospective Multicentre Single-Arm Registry Study.
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Noriega D, Maestretti G, Renaud C, Francaviglia N, Ould-Slimane M, Queinnec S, Ekkerlein H, Hassel F, Gumpert R, Sabatier P, Huet H, Plasencia M, Theumann N, Kunsky A, and Krüger A
- Subjects
- Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Prospective Studies, Back Pain surgery, Osteoporosis surgery, Quality of Life, Spinal Fractures surgery
- Abstract
This prospective, consecutive, multicentre observational registry aimed to confirm the safety and clinical performance of the SpineJack system for the treatment of vertebral compression fractures (VCF) of traumatic origin. We enrolled 103 patients (median age: 61.6 years) with 108 VCF due to trauma, or traumatic VCF with associated osteoporosis. Primary outcome was back pain intensity (VAS). Secondary outcomes were Oswestry Disability Index (ODI), EuroQol-VAS, and analgesic consumption. 48 hours after surgery, a median relative decrease in pain intensity of 81.5% was observed associated with a significant reduction in analgesic intake. Improvements in disability (91.3% decrease in ODI score) and in quality of life (increase 21.1% of EQ-VAS score) were obtained 3 months after surgery. All results were maintained at 12 months. A reduction in the kyphotic angulation was observed postoperatively (-5.4 ± 6.3°; p < 0.001), remained at 12 months (-4.4 ± 6.0°, p = 0.002). No adverse events were implant-related and none required device removal. Three patients (2.9%) experienced procedure-related complications. The overall adjacent fracture rate up to 1 year after surgery was 2.9%. The SpineJack procedure is an effective, low-risk procedure for patients with traumatic VCF allowing a fast and sustained improvement in quality of life over 1 year after surgery.
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- 2015
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32. [Non-invasive quantification of cartilage thickness and cartilage damage with MRI].
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Meurer AM, Engelhardt O, Giesa M, Hassel F, and Kreitner KF
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- Humans, Knee Joint pathology, Osteoarthritis, Knee pathology, Sensitivity and Specificity, Cartilage, Articular pathology, Magnetic Resonance Imaging, Osteoarthritis, Knee diagnosis
- Published
- 2003
33. Ein römisches Arztgrab des 3. Jahrhunderts n. Chr. aus Kleinasien.
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Hassel FJ and Künzl E
- Subjects
- Greek World, History of Medicine, Equipment and Supplies history, Mortuary Practice history
- Published
- 1980
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