近红外光谱方法在颌面外科皮瓣移植术后监测中的应用

近红外光谱技术作为一种无创组织氧监测手段,近年来在整形外科手术术后监测方面得到了越来越多的重视。文章利用一套近红外无损组织氧检测系统对6例手术成功病例的移植皮瓣侧和对照侧正常组织内的氧饱和度进行了长时间对比监测,发现两侧的组织氧饱和度之间存在显著性差异。还对一例血管吻合失败的病例下颌部的多个位置进行了检测,发现坏死部位的氧饱和度和正常组织相比处于很低的水平。实验结果表明,近红外光谱检测技术对于皮瓣内的血氧浓度动态变化具有很好的灵敏度,在移植皮瓣的术后监测方面具有良好的应用前景。     

Semi-invariants in surgery

A semi-invariant in surgery is an invariant of a quadratic Poincaré complex which is defined in terms of a null-cobordism. We define five such gadgets: the semicharacteristic, the semitorsion, the cross semitorsion, the torsion semicharacteristic, and the cross torsion semicharacteristic. We describe applications to the evaluation of surgery obstructions, especially in the odd-dimensional case.     

Nonspecific laryngeal granuloma: A case study of a professional singer

A professional singer with laryngeal granuloma underwent surgery following failed response to conservative treatments. Two primary findings emerged. First, although a sizable lesion was present initially, presurgical voice measures were largely normal or superior. The exception was elevated phonatory effort during singing. Second, postsurgical voice functions were entirely normal or superior (including phonatory effort), despite demanding singing performances a few weeks following surgery. The results add to the limited corpus of quantitative, normative-referenced data on voice in patients with granulomas and are inconsistent with previous reports of voice abnormalities in such patients and poor functional response to surgery.     

Effects of interactions among wave aberrations on optical image quality after refractive surgery

Research on wave aberrations indicates that interactions and balances among aberrations can provide better visual quality for normal eyes. In this paper, we investigate the aberration compensatory mechanism for eyes after LASIK surgery. Data of Zernike coefficients of wave-front aberrations are collected from 60 post-operative eyes through a Hartmann-Shack wave-front sensor, and then a series of Monte Carlo simulations are performed by manipulating the value of each Zernike coefficient (second order through seventh order). The modulation transfer function (MTF) ratio as a function of spatial frequency is used to evaluate the aberrations’ characteristic of independence. Finally, in a control condition, “synthetic” model eyes are produced through Monte Carlo arithmetic and the aberration independence of the synthetic eyes is analyzed. The results suggest that, for 6 and 3 mm pupil size, aberrations of the eyes after LASIK surgery are still not independent and the adaptive mechanism still exists. However, the adaptive mechanism does not hold for the “synthetic” eyes.     

Real-Time Tool Detection for Workflow Identification in Open Cranial Vault Remodeling

Deep learning is a recent technology that has shown excellent capabilities for recognition and identification tasks. This study applies these techniques in open cranial vault remodeling surgeries performed to correct craniosynostosis. The objective was to automatically recognize surgical tools in real-time and estimate the surgical phase based on those predictions. For this purpose, we implemented, trained, and tested three algorithms based on previously proposed Convolutional Neural Network architectures (VGG16, MobileNetV2, and InceptionV3) and one new architecture with fewer parameters (CranioNet). A novel 3D Slicer module was specifically developed to implement these networks and recognize surgical tools in real time via video streaming. The training and test data were acquired during a surgical simulation using a 3D printed patient-based realistic phantom of an infant’s head. The results showed that CranioNet presents the lowest accuracy for tool recognition (93.4%), while the highest accuracy is achieved by the MobileNetV2 model (99.6%), followed by VGG16 and InceptionV3 (98.8% and 97.2%, respectively). Regarding phase detection, InceptionV3 and VGG16 obtained the best results (94.5% and 94.4%), whereas MobileNetV2 and CranioNet presented worse values (91.1% and 89.8%). Our results prove the feasibility of applying deep learning architectures for real-time tool detection and phase estimation in craniosynostosis surgeries.     

On the singular PDE's geometry and boundary value problems

A geometric formulation of singular partial differential equations (PDEs) is considered. Surgery techniques and integral bordism groups are utilized, following previous works by Prástaro on PDEs, in order to build global solutions crossing also singular points and to study their stability properties.     

Stability of the p-Curvature Positivity under Surgeries and Manifolds with Positive Einstein Tensor

We establish the stability of the class of manifolds with positive p-curvature under surgeries in codimension p + 3. As a consequence of this result, we first obtain the classification of compact 2-connected manifolds of dimension 7 with positive Einstein tensor; and secondly the existence of metrics with positive Einstein tensor on any compact, simply connected, non-spin manifold of dimension 7 whose second homotopy group is isomorphic to Z₂.     

Four-Manifolds With Surface Fundamental Groups

We study the homotopy type of closed connected topological -manifolds whose fundamental group is that of an aspherical surface . Then we use surgery theory to show that these manifolds are -cobordant to connected sums of simply-connected manifolds with an -bundle over .

     

Signature Operators and Surgery Groups over C*-algebras

Let A be a unital complex C^* algebra, L^*(A) the projective symmetric surgery groups, and K_*(A) topological K theory. We define groups B^*(A) of bordism classes of Fredholm complexes over A with Poincaré duality. These generalize the de Rham complex. It is shown that there are isomorphisms B^*(A)K_* (A) and B^*(A) L_*(A) given by abstract versions of the signature operator and symmetric signature. The remaining side of a triangle is formed by an isomorphism due to Mienko.     

Near-infrared (NIR) spectroscopic evaluation of articular cartilage: A review of current and future trends

This review describes recent developments and applications of near-infrared (NIR) spectroscopy for characterization of articular cartilage integrity. It summarizes the research findings in this area and presents some spectral ranges and peaks associated with the different properties and components of articular cartilage. We further describe recent adaptations of NIR spectroscopy for clinical evaluation of articular cartilage injury and degeneration. Critical to accurate decision-making during repair surgery is having clear knowledge of lesion severity and spread, and how to grade the quality of surrounding cartilage. Thus, in this review, we detail efforts aimed at quantification and classification of cartilage pathology using NIR spectroscopy. Finally, we present open questions and challenges with a view to guiding future directions in NIR spectroscopy research on articular cartilage.