Endoscopic submucosal resection: a technique using novel devices for incision and resection of neoplastic lesions.

Background: Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are established techniques for treatment of superficial gastrointestinal neoplasia. Limitations of EMR are low en bloc resection rates for larger lesions, resulting in frequent recurrences. Major disadvantages of ESD are technical difficulty and long procedure times.

Shape Measures for Triangles.

We compare a variety of triangle shape measures using concepts such as smoothness and convexity. We show that one of these measures, the elongation measure, lends itself to an intuitive geometric interpretation.

High-quality rendering of quartic spline surfaces on the GPU.

We present a novel GPU-based algorithm for high-quality rendering of bivariate spline surfaces. An essential difference to the known methods for rendering graph surfaces is that we use quartic smooth splines on triangulations rather than triangular meshes. Our rendering approach is direct in the sense that since we do not use an intermediate tessellation but rather compute ray-surface intersections (by solving quartic equations numerically) as well as surface normals (by using Bernstein-Bézier techniques) for Phong illumination on the GPU.

Thin structure segmentation and visualization in three-dimensional biomedical images: a shape-based approach.

This paper presents a shape-based approach in extracting thin structures, such as lines and sheets, from three-dimensional (3D) biomedical images. Of particular interest is the capability to recover cellular structures, such as microtubule spindle fibers and plasma membranes, from laser scanning confocal microscopic (LSCM) data. Hessian-based shape methods are reviewed.

Crest lines for surface segmentation and flattening.

We present a method for extracting feature curves called crest lines from a triangulated surface. Then, we calculate the geodesic Voronoi diagram of crest lines to segment the surface into several regions. Afterward, barycentric surface flattening using theory from graph embeddings is implemented and, using the Geodesic Voronoi diagram, we develop a faster surface flattening algorithm.

Image registration using hierarchical B-splines.

Hierarchical B-splines have been widely used for shape modeling since their discovery by Forsey and Bartels. In this paper, we present an application of this concept, in the form of free-form deformation, to image registration by matching two images at increasing levels of detail. Results using MRI brain data are presented that demonstrate high degrees of matching while unnecessary distortions are avoided.

Improving the accuracy of volumetric segmentation using pre-processing boundary detection and image reconstruction.

The concentration edge -detection and Gegenbauer image-reconstruction methods were previously shown to improve the quality of segmentation in magnetic resonance imaging. In this study, these methods are utilized as a pre-processing step to the Weibull E-SD field segmentation. It is demonstrated that the combination of the concentration edge detection and Gegenbauer reconstruction method improves the accuracy of segmentation for the simulated test data and real magnetic resonance images used in this study.

[Effect of high frequency application on the tongue base. In vitro results of "radiofrequency application" on the porcine tongue base].

Background And Objective: A newly developed radio-frequency monopolar needle electrode was evaluated in vitro on porcine tongues.

Patients And Methods: Porcine tongues with different tissue temperatures (20+/-1) degrees C and (32+/-2) degrees C were coagulated for 90 s. In a second step, 23 coagulations at 7 W were applied (34+/-2) degrees C.

Technology of water-jet dissection.

For about 20 years, water-jet dissection has been used as a surgical technique. Due to the development of suitable instruments, devices, and operation strategies, water-jet dissection is becoming increasingly interesting for applications, especially for dissections where the atraumatical and/or tissueselective preparation or separation of tissue structures is mandatory. Prerequisites for the effective and safe application of the water-jet dissection are, on the one side, the knowledge of the relevant physical characteristics of the tissues in question, as well as their mechanical connections, and, on the other side, the knowledge of the relevant physical effects of a water-jet.

[Argon plasma coagulation in bronchology: a new method--alternative or complementary?].

Argon plasma coagulation (APC) is a thermal coagulation technique that uses ionized argon to transmit high-frequency electrical current, contact free, to tissue. APC has been used in surgery for more than 20 years, particularly for the hemostasis of superficial bleeding. Although APC has become well established in gastrointestinal endoscopy since its introduction in 1991, very few reports of its use in bronchoscopy exist to date.

New haemostatic techniques: argon plasma coagulation.

Bleeding is one of the main challenges for endoscopists. Despite a large number of methods for haemostasis, several types of haemorrhage lack an adequate therapeutic remedy. Argon plasma-coagulation (APC), a new method for the non-contact application of high-frequency current, promises to solve many of these problems.

[Argon plasma surgery (APC) in the upper aerodigestive tract. Initial results].

Cold knife surgery, electrosurgery and laser surgery all offer techniques, instruments, equipment and systems for resecting and destroying mucosal lesions and for hemostasis in the upper aerodigestive tract. When used in the head and neck, argon plasma surgery (APS) offers a new, contact-free, electrosurgical technique in which high frequency current is applied through ionized, and thus electrically conductive, argon(argon plasma) to the tissue undergoing treatment. Especially noteworthy in APS are its advantages for removing a lesion and controlling bleeding: the technique is easy to control, and the depth of the thermal tissue destruction is limited to a maximum of 3 mm even in wide-area application, so that damage to adjacent or submucosal tissues can be avoided.

Application of argon plasma coagulation in skin surgery.

Background: Argon plasma coagulation (APC) is a noncontact electrosurgical technique which has been used in open surgery for about 20 years and in endoscopy for about 5 years.

Objective: The aim of the present study was to provide preliminary results on the effect of this method in skin surgery.

Methods: The effects of variations in gas flow, output power and coagulation times on the extent of the resulting skin coagulation zone were tested in a pig skin model.

A new HF current generator with automatically controlled system (Endocut mode) for endoscopic sphincterotomy--preliminary experience.

Background And Study Aims: The main complications of endoscopic sphincterotomy are pancreatitis, hemorrhage, perforation and cholangitis. In a prospective randomized trial, a conventional current generator was compared to a new generator with an automatically controlled cut system (Endocut) for sphincterotomy. The purpose was to establish whether the new device reduces the complication rate of sphincterotomy.

[Argon plasma coagulation through a flexible endoscope. Evaluation of a new therapeutic method after 1606 uses].

Background And Objective: Argon plasma coagulation (APC) through a flexible endoscope provides a new technique for thermal devitalization or blood coagulation which is gaining wider attention. This study was undertaken to test clinically the efficacy, safety and ergonomics of the method.

Patients And Methods: 697 consecutive patients (386 men, 311 women; mean age 67 years [3 months--97 years]) had undergone the procedure in 1606 sitting since 1991.

High-Frequency Electrosurgery in Minimal Access Procedures.

In open surgery preparation, dissection and hemostasis are easy to perform compared with endoscopic surgery. In open surgery, the surgeon is able to use a variety of instruments and methods, In endoscopic surgery, scalpels cannot be used and the freedom of manipulation of instruments such as scissors and forceps is limited. Hence, endoscopic surgery depends on the availability of special methods, instruments, and equipments for different endoscopic operations.

Ultrasonic dissection in combination with high-frequency surgery.

Ultrasonic surgery is a technique used for tissue-selective dissection. High-frequency surgery, on the other hand, is a technique which permits largely non-selective cutting of all tissue except bone. Whereas ultrasonic surgery has no haemostatic effect, high-frequency surgery is highly effective for haemostasis.

Technology of argon plasma coagulation with particular regard to endoscopic applications.

Argon plasma coagulation is especially suited for thermal coagulation of tissue surfaces, for the haemostasis of surface bleeding and for the devitalisation of defined pathologic tissue layers. The maximum coagulation depth achievable under good control is 3-4 mm. Argon plasma coagulation has been tested successfully and is presently being used clinically in open surgery, especially for the haemostasis of surface bleeding in parenchymal organs.

Endoscopic argon plasma coagulation (APC) first clinical experiences in flexible endoscopy.

Argon plasma coagulation (APC) is a new mode of non-contact electrocoagulation in which current is applied to tissues by means of ionised argon gas (argon plasma). In open surgery, APC is used for the haemostasis of superficial, diffuse haemorrhages from parenchymatous organs and for the devitalization of various tissues. Experimental studies have shown the superiority of APC to standard electrocoagulation modes and surgical techniques due to its efficiency and limited tissue traumatisation.

[Endoscopic argon gas coagulation--initial clinical experiences].

Argon-gas-coagulation represents a new method of contact free electrocoagulation, where RF-energy is applied to the tissue by means of ionized argon-gas. In the operative field argon-gas-coagulation has been used with success for hemostasis in several parenchymatous organs and for devitalization of various tissues. Experimental studies have shown the superiority of argon-gas-coagulation over standard electrocoagulation and surgical techniques due to its high efficiency and limited tissue traumatization.

Pneumatically controlled bipolar cutting instrument.

A multifunctional instrument for transanal endoscopic microsurgery is presented. This instrument combines the functions of cutting, coagulation, suction and/or rinsing. The automatically effected pneumatic control of the functional elements of such an instrument can improve its serviceability not only with regard to safety but also to its ergonomic features.