Virtual grasping: closed-loop force control using electrotactile feedback.

Closing the control loop by providing somatosensory feedback to the user of a prosthesis is a well-known, long standing challenge in the field of prosthetics. Various approaches have been investigated for feedback restoration, ranging from direct neural stimulation to noninvasive sensory substitution methods. Although there are many studies presenting closed-loop systems, only a few of them objectively evaluated the closed-loop performance, mostly using vibrotactile stimulation. Importantly, the conclusions about the utility of the feedback were partly contradictory. The goal of the current study was to systematically investigate the capability of human subjects to control grasping force in closed loop using electrotactile feedback. We have developed a realistic experimental setup for virtual grasping, which operated in real time, included a set of real life objects, as well as a graphical and dynamical model of the prosthesis. We have used the setup to test 10 healthy, able bodied subjects to investigate the role of training, feedback and feedforward control, robustness of the closed loop, and the ability of the human subjects to generalize the control to previously "unseen" objects. Overall, the outcomes of this study are very optimistic with regard to the benefits of feedback and reveal various, practically relevant, aspects of closed-loop control.

Preservation surgery in patients with localized renal cell cancer--nephron sparing surgery.

INTRODUCTION: Renal Cell Cancer ( RCC) is third most frequent urological cancer behind Prostate cancer and Bladder cancer. It represents 2-3 % of all cancers with annual increase in incidence of 2% in Europe (except Denmark and Sweden) and worldwide. Surgery is the only curative procedure, performed as radical nephrectomy (RN) or partial nephrectomy (nephron sparing surgery-NSS). Radical nephrectomy consists of nephrectomy with ipsilateral adrenalectomy and lymphadenetomy, but partial nephrectomy means resection of the tumor only with 1-3 mm of healthy surrounding tissue and preservation of the rest of the kidney as well as ipsilateral adrenal gland and lymph nodes. NSS is a method of conservation of attacked kidney and preservation of kidney's function with previous radical resection of localized RCC, respecting of all oncological principles. The aim of this study is to describe NSS procedure in details and present results of its 13 year use at Clinic of Urology in Novi Sad. MATERIAL AND METHODS: In the last 13 years there were 868 patients (pts) with RCC. NSS has been performed in 242 pts (27.88%). Bilateral tumors: synchronous 8 pts, asynchronous 3 pts. Better kidney has been operated, first. Indications for NSS were: absolute--34 pts (15.0%), relative--58 pts (23.1%) and elective--150 pts (61.9%).Surgery was performed according to esta- blished protocol for this procedure based on recommendation of Prof. A. Novick, Cleveland, USA. RESULTS: All patients underwent surgery under general anesthesia through lumbothomy, mostly.Tumor size was between 2.5-4.5 cm: over 4.5 cm (4-7 cm): 4 pts. Average age of pts--63.5 years (37-84), male: 148 (61.1%), female: 94 (38.9%). From 2001-2005, 2006-2010 i 2011-2013, 39,111 i 92 NSS has been done, respectively. It represented 13.5%, 36.6% , 50.54% of all pts with RCC underwent surgery in that period, respectively. There was an increase of NSS in that period compared to RN for localized RCC. There were no death outcomes inpts underwent NSS, local recurrence was seen in 1 patient (0.6%), urine leakage > 2 weeks 5 pts (5/242 = 2.06%),severe hemorrhage: 3 pts (1.23%), nephrectomy has been done. We do not have patients with von Hippel Landau (VHL) disease. CONCLUSION: Nephron sparing surgery Is the first choice of surgery for patients with low grade kidney tumors (up to 4.5 cm, even 7 cm), has excellent onco- logical results-comparable with radical nephrectomy, but with preservation of renal function and should be done by an experienced urological team in specialized urological centers with good anesteziological support.