腓骨皮弁による下顎骨再建術術後のインプラント周囲軟組織における治療方法の検討

In maxillofacial reconstruction implant treatment, unsatisfactory soft tissue treatment of the area around the implant may lead to inflammation. As a result, appropriate soft tissue treatment is critical. To the best of our knowledge, there are no studies that compare the different tissue treatment methods available. Hence, in this study, we compare three soft tissue treatment methods around implants after mandibular reconstruction is achieved with a fibula-free flap. Out of 33 patients who underwent mandible reconstruction using fibula-free flaps between 2006 and 2015, 5 were selected for this study. A total of 17 implants were used for treatment by the final prosthetics of the five patients. Three soft tissue treatment methods with free gingival graft (FGG) were evaluated, namely, installing a splint in a modified abutment to protect the wounded area during a palatal mucosa transplant (method 1), installing a splint or dentures to a locator abutment (method 2), and the use of screw-in fixed dentures (method 3). The method that could guarantee the widest keratinized mucosa was the screw-in fixed denture method. The results of our study indicated that employing screw-in fixed dentures for FGG may be a useful soft tissue treatment for mandible reconstruction implants.博士（医学）・乙第1491号・令和2年12月24日Copyright © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

Enumerated sparse extraction of important surgical planning features for mandibular reconstruction

[2020 42nd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC 2020); Montreal, Quebec, Canada, 20-24 July 2020]Because implicit medical knowledge and experience are used to perform medical treatment, such decisions must be clarified when systematizing surgical procedures. We propose an algorithm that extracts low-dimensional features that are important for determining the number of fibular segments in mandibular reconstruction using the enumeration of Lasso solutions (eLasso). To perform the multi-class classification, we extend the eLasso using an importance evaluation criterion that quantifies the contribution of the extracted features. Experiment results show that the extracted 7-dimensional feature set has the same estimation performance as the set using all 49-dimensional features

Automated Planning with Multivariate Shape Descriptors for Fibular Transfer in Mandibular Reconstruction

Objective: This paper introduces methods to automate preoperative planning of fibular segmentation and placement for mandibular reconstruction with fibular flaps. Methods: Preoperative virtual planning for this type of surgery has been performed by manual adjustment of many parameters, or based upon a single feature of the reconstruction. We propose a novel planning procedure formulated as a non-convex minimization problem of an objective function using the multilateral shape descriptors. Results: A retrospective study was designed and 120 reconstruction plans were reproduced using computed tomography images with oral surgeons. The proposed automated planning model was quantitatively compared with both the existing model and the surgeons’ plans. Conclusion: The results show that the developed framework attains stable automated planning that agrees with the surgeons’ decisions. Significance: This method addresses trade-off problems between symmetric reconstruction and restoration of the native contour of the mandible

Association between contrast extravasation on computed tomography scans and pseudoaneurysm formation in pediatric blunt splenic and hepatic injury: A multi-institutional observational study

PURPOSE: We aimed to examine the association between contrast extravasation (CE) on initial computed tomography (CT) scan and pseudoaneurysm (PSA) development in pediatric blunt splenic and/or liver injury. METHODS: We conducted a multi-institutional retrospective study in cases of blunt splenic and/or hepatic injury who underwent an initial attempt of nonoperative management. A logistic regression model was used to compare PSA formation and CE on initial CT scan, and the area under the receiver operating characteristic curve (AUC) with and without CE was used to assess the predictive performance of CE for PSA formation. RESULTS: Of 236 cases enrolled from 10 institutions, PSA formation was observed in 17 (7.2%). Multivariate analysis showed a significant association between CE on initial CT scan and increased incidence of PSA formation (odds ratio, 4.96; 95% confidence interval, 1.37-18.0). There was no statistically significant association between the grade of injury and PSA formation. The AUC improved from 0.75 (0.64-0.87) to 0.80 (0.70-0.91) with CE. CONCLUSION: Active CE on initial CT scan was an independent predictor of PSA formation. Selective use of follow-up CT in children who showed CE on initial CT may provide early identification of PSA formation, regardless of injury grade. LEVEL OF EVIDENCE: Prognostic and epidemiological, level III

AGN number fraction in galaxy groups and clusters at z < 1.4 from the Subaru Hyper Suprime-Cam survey

One of the key questions on active galactic nuclei (AGN) in galaxy clusters is how AGN could affect the formation and evolution of member galaxies and galaxy clusters in the history of the Universe. To address this issue, we investigate the dependence of AGN number fraction ($f_{\rm AGN}$) on cluster redshift ($z_{\rm cl}$) and distance from the cluster center ($R/R_{\rm 200}$). We focus on more than 27,000 galaxy groups and clusters at $0.1 < z_{\rm cl} < 1.4$ with more than 1 million member galaxies selected from the Subaru Hyper Suprime-Cam. By combining various AGN selection methods based on infrared (IR), radio, and X-ray data, we identify 2,688 AGN. We find that (i) $f_{\rm AGN}$ increases with $z_{\rm cl}$ and (ii) $f_{\rm AGN}$ decreases with $R/R_{\rm 200}$. The main contributors to the rapid increase of $f_{\rm AGN}$ towards high-$z$ and cluster center are IR- and radio-selected AGN, respectively. Those results indicate that the emergence of the AGN population depends on the environment and redshift, and galaxy groups and clusters at high-$z$ play an important role in AGN evolution. We also find that cluster-cluster mergers may not drive AGN activity in at least the cluster center, while we have tentative evidence that cluster-cluster mergers would enhance AGN activity in the outskirts of (particularly massive) galaxy clusters.Comment: 16 pages, 21 figures, and 2 tables, accepted for publication in PAS