Biomedical subjects

P V Pistecky

Publications and source records attributed to P V Pistecky.

5 recordsLinked to original sources

PubMed2005

Behavior of arthroscopic irrigation systems.

In the literature, no consensus exists about optimal irrigation of joints during arthroscopic operations. The goal of this paper is to study the behavior of irrigation systems resulting in the proposal of guidelines for optimal irrigation. To this end, optimal irrigation is defined as the steady state of irrigation of a joint in which a sufficient positive intra-articular pressure and a sufficient flow are maintained. A model of the complete irrigation system was created to schematically elucidate the behavior of pump systems. Additionally, clinical experiments were performed during arthroscopic knee operations in which the pressure at different locations and the irrigation flow were measured. The combination of model prediction and clinical results could well be used to derive guidelines, since the clinical results, which showed considerable variation, were used to verify the model, and the model could be used to explain the typical trends. The main findings are twofold the set pressure is always higher than the intra-articular pressure, and the scope-sheath combination has a significant influence on irrigation control, because of its large restriction. Based on the results, we advice to increase the set pressure during active suction, and to include the sheath-scope combination in the control loop.

Adult↗

PubMed2003

Clinically-driven approach to improve arthroscopic techniques.

In this paper, a clinically-driven approach is introduced as the starting point for the improvement of arthroscopic techniques. The approach was divided into two phases. Phase 1 consisted of a combination of observations and discussions that resulted in the definition of clinically-relevant research topics. Phase 2 consisted of an interview which aimed at analysis of the general opinion on arthroscopy, and which assigned a priority ranking to the topics. Six research topics were defined. Based on the information collected, the conclusion is that the surgeons are satisfied with current arthroscopic techniques. A majority gives priority to the optimization of cartilage treatment and to the design of a steerable arthroscopic cutter. A minority gives priority to the expansion of arthroscopic techniques. The two-phase approach was fruitful in terms of establishing clinical problem areas, and of involving surgeons in the technical improvement of arthroscopic techniques.

Arthroscopes↗

PubMed2002

Forces and displacements in colon surgery.

BACKGROUND: This study aims to find criteria for designing safer laparoscopic graspers for manipulation of delicate tissues. Since the experiment was performed in an open-surgery setup without any movement restrictions, the results are relevant to general surgery as well as laparoscopic. METHOD: Four surgeons were asked to apply via two clamps enough force to a pig's colon to stretch the mesocolon for dissection. Directions, magnitudes, and application points of the forces were recorded. RESULTS: The surgeons applied per clamp on average 2.5 N and maximally 5 N to the colon. These forces were at an angle of about 40 degrees to 70 degrees relative to the horizontal plane and approximately 60 degrees relative to each other. CONCLUSIONS: Safe laparoscopic graspers should be able to transmit at least a 5 N pull force to the tissue without damaging it. To minimize the forces used, the angles mentioned should be taken into account when placing the trocars.

Animals↗

PubMed2000

Assessment of patented coronary end-to-side anastomotic devices using micromechanical bonding.

BACKGROUND: Despite multiple patented ideas for vascular end-to-side anastomotic devices, and the growing need for them in minimally invasive coronary bypass procedures, no device has been evaluated clinically yet. This study assessed patents of micromechanical end-to-side anastomotic devices with respect to application in coronary artery bypass grafting. METHODS: Patents were categorized with respect to their micromechanical bonding principle. Calculated values for the wall strain during the construction of an anastomosis were compared with the allowable strain for human coronary arteries. RESULTS: From 51 patents describing vascular anastomotic devices, 11 ideas, categorized into four groups (staples, clips, mounting systems, and intraluminal stent structures), are serious candidates for coronary end-to-side anastomoses. Most ideas use an anvil for proper application of the bonding elements. For small (1.5 mm) coronary arteries, the calculated wall strain was 0.87, exceeding the breaking strain (0.45) in 60- to 79-year-old patients. CONCLUSIONS: In a coronary anastomotic device, the concept of using an anvil for the application of micromechanical bonding elements is not attractive, because excessive wall strain is likely to occur.

Anastomosis, Surgical↗

PubMed1992

A compact body mass measuring device for space flight applications.

During spaceflights, it is important to measure an astronaut's body mass ('weight'), both for investigating the influence of the space environment on the human body and for monitoring the physical (health) condition of the astronaut. This paper reports the development of a mass measuring device that is compact, user friendly, and has an absolute measuring accuracy better than 60 gram. The measurement accuracy turns out to be restricted by the way a human body is configured by nature and not by the instrument itself, that has an accuracy much better than required.

Acceleration↗