Úvod: Autoři prezentují svoje zkušenosti s roboticky asistovanou resekcí ledviny pro tumor (Robot- -assisted partial nephrectomy, RAPN). Materiál: Od června 2010 do června 2015 jsme na našem pracovišti provedli 85 RAPN. Zkušenosti s minimálně invazivní resekcí ledviny získáváme od r. 2005, kdy jsme začali provádět laparoskopické resekce, kterých jsme do dneška provedli přes 120. Počet indikovaných pacientů roste s tím, jak narůstá počet k resekci vhodných nádorů a jak se také zvyšuje zkušenost chirurgického týmu, což nám umožňuje ošetřit i méně příznivě lokalizované tumory. Popis metody: Využíváme robotický systém II. generace DaVinci® S™. Používáme standardně transperitoneální přístup za použití 4–5 trokarů, kdy u pacienta ležícího na boku nejprve vypreparujeme vstup pro 12mm kamerový trokar (tzv. open access). Pro robotický systém používáme dva pracovní nástroje (2x8 mm trokar), jeden 12mm asistenční trokar a dle potřeby i druhý asistenční trokar 5mm. Kapnoperitoneum používáme s tlakem 12 mmHg. Otevřeme zadní peritoneum, mobilizujeme colon a otevřeme Gerotovu fascii. V nutném rozsahu obnažíme ledvinu k ozřejmění tumoru, ten si vždy verifikujeme pomocí ultrazvukové endoskopické sondy. Pomocí ultrazvuku najdeme okraje tumoru a tyto si označíme elektrokoagulací. Dle nálezu si vypreparujeme hilus ledviny, kde si zajistíme renální arterii hadičkou a buldokem ji klampujeme. Lze uvažovat i o selektivním klampování větve vedoucí k tumoru, což neprovádíme standardně. Při men- ším vhodně uloženém tumoru arterii neklampujeme vůbec (zero ischemia). Vlastní odstranění tumoru se provádí kombinací ostré a tupé preparace s dostatečným lemem zdravé tkáně. Ostrá resekce se provádí nůžkami bez použití elektrokoagulace, abychom dobře viděli resekovanou plochu a nezasáhli do tumoru. Resekovanou plochu poté vždy ošetříme argonovou koagulací a uzavíráme ji ve dvou vrstvách. Nejprve používáme vstřebatelný Safil 3/0 s uzlíkem a klipem na konci, který vedeme z vnějšku na spodinu resekované plochy, tuto několikrát prošijeme a poté opět steh vyvedeme vně a pomocí klipu dotáhneme. Druhý vstřebatelný steh šijeme matracově za použití hem-o-lok™ klipů (metoda sliding clips), pomocí kterých resekovanou plochu uzavřeme. Dle potřeby použijeme hemostatické prostředky, jako např. celulózu. Ideálně uzavřeme i Gerotovu fascii. Na závěr vytáhneme tumor se sáčkem a zavedeme Redonův drén. Mo- čový katétr je ponechán do druhého dne. Během výkonu je používaná zvyklá anestezie a pooperační analgezie. Výsledky: Průměrná délka výkonu (console time) byla 59 min (45–120 min), délka ischemie 12 min, ve 30 případech byla vzhledem k malé velikosti a příznivé lokalizaci nádoru provedena resekce bez ischemie. Průměrné krevní ztráty byly 120 ml (20–300 ml). V této sestavě se nevyskytly žádné komplikace vyžadující krevní převody, konverze nebo operační revize. Histologicky se jednalo o 82 světlobuněčných renálních karcinomů, ve třech případech byl popsán onkocytom. Velikost tumoru byla průměrně 3,9 cm (1,5–10 cm). Ve všech případech byly popsány negativní chirurgické okraje a i přes krátké sledování nedošlo k recidivě onemocnění. Závěr: Roboticky asistovaná resekce ledviny významně zlepšuje přehled i operační možnosti malých nádorových lézí ledvin. S použitím moderních prostředků (sliding clips) dochází k redukci doby ischemie i k redukci komplikací., Introduction: In this video we present our experience with robot-assisted partial nephrectomy (RAPN). Material: Between June 2010 and June 2015, we performed 85 RAPNs. Our first experience with minimally invasive partial nephrectomy dates back to 2005, when we did our first laparoscopic resection (since that time more than 120 laparoscopic partials were done). The number of patients treated is still growing due to the increasing number of small renal masses detected and our increasing experience with more advanced tumours (size and location). We are now able to resect even some unpleasantly located kidney tumours. Our technique: Partial nephrectomies were done using 2nd generation DaVinci® S™ system. We are performing transperitoneal approach with 4–5 ports and standard patient positioning (flank position, slightly bent). We start with open access for the 12mm camera port. Then we use two 8mm ports for the robotic arms and 12mm and sometimes another 5mm port for the assistant. The abdomen is insufflated with CO2 to 12 mmHg. We mobilise the colon, open Gerota fascia and remove the perirenal fat to expose the tumour. The tumour margins are identified using ultrasound. They are then scored circumferentially by electro cautery. Then we prepare the renal hilum. A vessel loop is put around the renal artery, which is then clamped using a bull dock. We do not usually do selective clamping. But in selected cases (small tumour, favourable location) we resect the kidney without clamping the artery (zero ischemia). Dissection of the tumour is done using blunt and sharp technique. Electro cautery is not used, for it would impair the visual control. The tumour is placed in an endobag. We then use plasma argon coagulation for the resected margin. The resected kidney is closed in two layers. We start with braided absorbable Safil 3–0 suture with a knot and clip at one end. This suture goes from outside in, several turns are done to close the major vessels or calices, then it goes out so another clip can be placed at the end and the suture tightened. The second suture is done using sliding clips technique. Haemostatic agents are used if necessary. We also try to close the Gerota fascia. At the end we always place a Redon drain. Urinary catheter is removed on the first post-operative day. Surgery is performed under standard general anaesthesia with commonly used postoperative analgesics. Results: Mean console time was 59 min (45–120 min), warm ischemia time was 12 min, in 30 cases there was zero ischemia time. This could be done due to small size and favourable location of the tumour. Mean blood loss was 120 ml (20–300 ml). There were no conversions to open surgery and there were no major complications requiring surgery (Clavien IIIb). In 2 cases we had to insert DJ stent due to urinoma (Clavien IIIa). RCC was found in 82 cases and in 3 cases oncocytoma. The mean size of the tumour was 3.9 cm (1.5–10 cm). The surgical margins were negative in all cases, and so far there has been no relapse of tumour. Conclusion: RAPN showed very good results, enhanced the visual control and manoeuvrability, thus extending the number of tumours that can be managed using minimally invasive technique. Using the novel techniques (sliding clips) both warm time ischemia and complication rates can be reduced., Vladimír Študent ml., Igor Hartmann, Aleš Vidlář, Michal Grepl, Vladimír Študent, and Literatura
This paper presents a procedure for constructing a stable decentralized output feedback controller for a class of uncertain systems in which the uncertainty is described by Integral Quadratic Constraints. The controller is constructed to solve a problem of robust H∞ control. The proposed procedure involves solving a set of algebraic Riccati equations of the H∞ control type which are dependent on a number of scaling parameters. By treating the off-diagonal elements of the controller transfer function matrix as uncertainties, a decentralized controller is obtained by taking the block-diagonal part of a non-decentralized stable output feedback controller which solves the robust H∞ control problem. This approach to decentralized controller design enables the controller to exploit the coupling between the subsystems of the plant.
This paper treats the question of robust control of chaos in modified FitzHugh-Nagumo neuron model under external electrical stimulation based on internal model principle. We first present the solution of the global robust output regulation problem for output feedback system with nonlinear exosystem. Then we show that the robust control problem for the modified FitzHugh-Nagumo neuron model can be formulated as the global robust output regulation problem and the solvability conditions for the output regulation problem for the modified FitzHugh-Nagumo neuron model are all satisfied. Then we apply the obtained output regulation results to the control problem for modified FitzHugh-Nagumo neuron model. Finally, an output feedback control law is designed for the modified FitzHugh-Nagumo neuron model to achieve global stability of the closed-loop system in the presence of uncertain parameters and external stimulus. An example is shown that the proposed algorithm can completely reject the external electrical stimulation generated from a Van der Pol circuit.
The paper addresses the problem of the robust output feedback controller design with a guaranteed cost and parameter dependent Lyapunov function for linear continuous time polytopic systems. Two design methods based on improved robust stability conditions are proposed. Numerical examples are given to illustrate the effectiveness of the proposed methods. The obtained results are compared with other three design procedures.
In this paper, the distributed output regulation problem of uncertain multi-agent systems with switching interconnection topologies is considered. All the agents will track or reject the signals generated by an exosystem (or an active leader). A systematic distributed design approach is proposed to handle output regulation via dynamic output feedback with the help of canonical internal model. With common solutions of regulator equations and Lyapunov functions, the distributed robust output regulation with switching interconnection topology is solved.
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