Reducing Degrees of Freedom in Surgical Suturing: Implications for Minimally Invasive Device Development-A Prospective Experimental Study.

Open surgery allows the use of all 6 degrees of freedom (DOF; x-y-z and roll-pitch-yaw), whereas laparoscopy requires working under limitation to 4 axes. We present a prospective experimental study evaluating translational and rotational DOF restriction in surgical suturing tasks. An experimental platform included a kinematic structure that limited the maneuverability of the surgical instruments.

Detection of adverse events leading to inadvertent injury during laparoscopic cholecystectomy using convolutional neural networks.

Uncontrolled movements of laparoscopic instruments can lead to inadvertent injury of adjacent structures. The risk becomes evident when the dissecting instrument is located outside the field of view of the laparoscopic camera. Technical solutions to ensure patient safety are appreciated.

Thinking About Pathomechanisms and Current Treatment of Erectile Dysfunction-"The Stanley Beamish Problem." Review, Recommendations, and Proposals.

Introduction: Up to 50% of all men over 50 years of age suffer from erectile dysfunction. Since the late 1990s erectile dysfunction has been treated mostly with phosphodiesterase 5 inhibitors (PDE5I). Over the past 20 years, numerous scientific findings on the development of erectile dysfunction have been collected, which have so far received little attention in the treatment of erectile dysfunction.

Impact of haptic feedback on applied intracorporeal forces using a novel surgical robotic system-a randomized cross-over study with novices in an experimental setup.

Background: Most currently used surgical robots have no force feedback; the next generation displays forces visually. A novel single-port robotic surgical system called FLEXMIN has been developed. Through an outer diameter of 38 mm, two instruments are teleoperated from a surgeon's control console including true haptic force feedback.

Learning curves, potential and speed in training of laparoscopic skills: a randomised comparative study in a box trainer.

Background: The effectiveness of practical surgical training is characterised by an inherent learning curve. Decisive are individual initial starting capabilities, learning speed, ideal learning plateaus, and resulting learning potentials. The quantification of learning curves requires reproducible tasks with varied levels of difficulty.

The impact of guided instrument insertion during laparoscopy: a randomized study with novices in an optical box trainer.

Background: During laparoscopic operations, the trocars are often out of the viewing field of the laparoscope. Blind insertion of laparoscopic instruments is potentially dangerous especially when they are pointed or hot. A guidance of the instrument to the target point has the potential to improve the safety of instrument insertion.

How Much Stereoscopic Effect Does Laparoscopy Need? Controlled, Prospective Randomized Trial on Surgical Task Efficiency in Standardized Phantom Tasks.

Background: To regain 2-eyed vision in laparoscopy, dual-channeled optics have been introduced. With this optics design, the distance between the 2 front lenses defines how much stereoscopic effect is seen. This study quantifies the impact of an enhanced and a reduced stereo effect on surgical task efficiency.

[3D in laparoscopy: state of the art].

High definition stereoscopic (3D) vision has been introduced into the operation theatre. This review exposes the optical and physiological background as well as the state of the art of 3D in laparoscopy. The distinguishing marks of 3D laparoscopes and monitors are listed and characteristics of stereoscopy, such as comfort zones and ghosting are explained.

For 3D laparoscopy: a step toward advanced surgical navigation: how to get maximum benefit from 3D vision.

The authors are grateful for the interesting perspectives given by Buchs and colleagues in their letter to the editor entitled "3D Laparoscopy: A Step Toward Advanced Surgical Navigation." Shutter-based 3D video systems failed to become established in the operating room in the late 1990s. To strengthen the starting conditions of the new 3D technology using better monitors and high definition, the authors give suggestions for its practical use in the clinical routine.

3D HD versus 2D HD: surgical task efficiency in standardised phantom tasks.

Background: Common video systems for laparoscopy provide the surgeon a two-dimensional image (2D), where information on spatial depth can be derived only from secondary spatial depth cues and experience. Although the advantage of stereoscopy for surgical task efficiency has been clearly shown, several attempts to introduce three-dimensional (3D) video systems into clinical routine have failed. The aim of this study is to evaluate users' performances in standardised surgical phantom model tasks using 3D HD visualisation compared with 2D HD regarding precision and working speed.

Transanal endoscopic microsurgery-based transanal access for colorectal surgery: experience on human cadavers.

Transanal endoscopic microsurgery (TEM) was described in 1983 for local excision of rectal tumors. In the context of natural orifice translumenal endoscopic surgery, we have modified the original TEM system and developed a new set of instruments. These are more curved and, in addition, steerable.

Inhibition of smooth muscle cell proliferation after local drug delivery of the antimitotic drug paclitaxel using a porous balloon catheter.

Percutaneous transluminal coronary angioplasty is an accepted treatment for coronary artery disease. The major limitation, however, is the high incidence of restenosis which limits the long-term benefit of this intervention. Paclitaxel is a new antiproliferative agent that has generated considerable scientific interest since it was introduced in clinical trials in the early 1980s.

[Shadow optic. An endoscope with optimized ligth].

Modern endoscopes use a single mid-frontal illumination source that yields an unnatural flat image. At the University of Tübingen, in collaboration with Gimmi GmbH (Tuttlingen, Germany), a new concept endoscope has been developed with an additional light source: the shadow optic. With the aid of a secondary light source along the axis of the endoscope, a shadow is obtained which gives an impression of spatial depth.

The effect of high-definition imaging on surgical task efficiency in minimally invasive surgery: an experimental comparison between three-dimensional imaging and direct vision through a stereoscopic TEM rectoscope.

Background: In 1995, when we first used a high-definition television (HDTV) video system during a laparoscopic cholecystectomy in Tuebingen, we were surprised by the excellence of the spatial impression achieved by an image with improved resolution. Although any improvement in vision systems entails a trade-off among cost, quality, and complexity, high-definition imaging may well become an essential part of 3-D video systems. The aim of this experimental study was to assess the impact of high definition on surgical task efficiency in minimally invasive surgery and to determine whether it is preferable to use a 3-D system or a 2-D system with perfect resolution and color--for instance, HDTV or the three-chip charge-coupled device (3CCD).

Three-dimensional (3-D) video systems: bi-channel or single-channel optics?

Background And Study Aims: This paper presents the results of a comparison between two different three-dimensional (3-D) video systems, one with single-channel optics, the other with bi-channel optics. The latter integrates two lens systems, each transferring one half of the stereoscopic image; the former uses only one lens system, similar to a two-dimensional (2-D) endoscope, which transfers the complete stereoscopic picture.

Material And Methods: In our training centre for minimally invasive surgery, surgeons were involved in basic and advanced laparoscopic courses using both a 2-D system and the two 3-D video systems.

The role and future of endoscopic imaging systems.

Visual perception is the main sensory input from the environment in most situations of daily life. It is the only sensory input from the operating field in endoscopic surgery, and thus the qualities of the optical imaging system have a considerable impact on the course of the surgical intervention. Significant improvements have been made recently in various fields of science and engineering, influencing endoscopic imaging systems in experimental and clinical use.

Comparative study of two-dimensional and three-dimensional vision systems for minimally invasive surgery.

Background: The aim of this comparative study was to gain subjective and objective data to determine for which operative tasks three-dimensional (3-D) vision systems are superior to two-dimensional (2-D) systems and to demonstrate any advantages or disadvantages of 3-D systems.

Methods: A model with five standardized tasks including sewing and knotting was developed to objectively measure performance times and to count technical faults. In our training center for minimally invasive surgery, surgeons involved in basic and advanced laparoscopic courses trained using both 2-D and 3-D vision systems.

Paclitaxel inhibits arterial smooth muscle cell proliferation and migration in vitro and in vivo using local drug delivery.

Background: The antineoplastic compound paclitaxel (Taxol) causes an increased assembly of extraordinarily stable microtubules. The present study was designed to characterize the effects of paclitaxel on proliferation and migration of human arterial smooth muscle cells (haSMCs) in vitro and on neointima formation in an in vivo experimental rabbit model.

Methods And Results: Both monocultures of haSMCs and cocultures with human arterial endothelial cells (haECs) were used.

Efficacy of low-molecular-weight heparin delivery with the Dispatch catheter following balloon angioplasty in the rabbit iliac artery.

Local drug delivery can be achieved with active injection systems or passive contact of a compound with the arterial wall. The Dispatch catheter allows for passive diffusion of drugs from drug compartments while preserving blood flow through the central conduit. The aim of this study was to investigate whether a reduction in neointima formation can be achieved by local delivery of a limited amount of a highly concentrated solution of the low-molecular-weight heparin Reviparin.

[Optics with natural appearing added illumination].

Today's endoscopes use a central frontal illumination which creates huge contrast, no visible shadows, and gives an unnaturally flat impression. In the SIMIC project, a new type of optics has been developed that uses additional illumination fibres ending 3 mm behind the front lens. This gives a more natural and spatial impression of the body cavity, causes shadows that are an improvement when approaching tissue with an instrument, reduces blooming in the foreground, and improves detail reproduction in the background.

[Comparative study of various 2-D and 3-D vision systems in minimally invasive surgery].

The aim of this comparative study was to gain subjective and objective data to determine for which operative tasks it is useful to work with 3-D rather than 2-D vision systems and to show the advantages and disadvantages of 3-D systems. A series of five standardized tasks like sewing and tying knots was set up to measure performance times objectively and to count errors. Compared with 2-D vision, the performance time was 32% shorter and 43% fewer errors were made under 3-D vision (P < 0.

[Minimally invasive ENT surgery. Progress due to modern technology].

Three fundamentals have to be fulfilled to optimize minimally, invasive surgery: three-dimensional imaging, free maneuverability of the instruments, sensorial feedback. Projection of two pictures from a stereoendoscope and subsequent separation with a LCD shutter allows three-dimensional videoendoscopy to be performed. A high-frequency shutter technique (100/120 Hz) presents pictures from the two video cameras to the right and left eye, respectively, so that the surgeon has spatial vision of the operative field.

Experimental telemanipulation in endoscopic surgery.

Today's rigid endoscopic instruments limit the intracorporeal mobility of the surgical tool and are a severe impediment for the further spread of endoscopic techniques in operative medicine. Since 1992 flexible, steerable instruments with additional links for pivoting and rotating the tip have been developed and experimentally evaluated. The latest versions of this series of instruments are equipped with electromotors for better handling.

[Comparative study of endoscopic 2-D and 3-D imaging systems].

The aim of this comparative study is to gain subjective and objective data to determine for which operative task it is more useful to work with 3-D than 2-D vision systems, in order to show the advantages and disadvantages of 3-D systems. A parcour with five standardized tasks, e.g.

Histologic effects of different technologies for dissection in endoscopic surgery: Nd:YAG laser, high frequency and water-jet.

Precise cutting combined with reliable coagulation of the margins of the lesion is an important requirement for dissection techniques in endoscopic surgery. These requirements are met by the two most common ancillary energy sources applied for endoscopic dissection today, electrosurgery and "thermal lasers", mostly the Nd:YAG. For the comparison of the histological effects of monopolar and bipolar high frequency with the Nd:YAG laser an experimental in vitro and in vivo study has been performed.