An efficient algorithm for the calculation of the inverse kinematics and dynamics considering a parallel robot with two movable platforms is proposed. The approach is based on the Newton-Euler formalism, the virtual work principle, and the usage of the instantaneously coincident coordinate frame of the robot base. Corresponding to a hand-held surgical robot application, the derived inverse dynamics solution is capable to describe the forces which are required (1) to generate the desired motion of the tool and (2) to decouple the tool from disturbances induced at the base.

To describe fluocinolone acetonide implant dissociations in the Multicenter Uveitis Steroid Treatment (MUST) Trial.Randomized clinical trial with extended follow-up.Review of data collected on the first implant in the eye(s) of participants. Dissociation was defined as the drug pellet no longer being affixed to the strut and categorized as spontaneous or surgically related.A total of 250 eyes (146 patients) had at least 1 implant placed. Median follow-up time after implant placement was 6 years (range 0.5–9.2 years). Thirty-four dissociations were reported in 30 participants. There were 22 spontaneous events in 22 participants; 6-year cumulative risk of a spontaneous dissociation was 4.8% (95% confidence interval [CI]: 2.4%–9.1%). The earliest event occurred 4.8 years after placement. Nine of 22 eyes with data had a decline in visual acuity ≥5 letters temporally related to the dissociation. Thirty-nine implant removal surgeries were performed, 33 with replacement. Twelve dissociations were noted during implant removal surgeries in 10 participants (26%, 95% CI 15%–48%); 5 of these eyes had a decline in visual acuity ≥5 letters after surgery. The time from implant placement to removal surgery was longer for the surgeries at which dissociated implants were identified than for those without one (5.7 vs 3.7 years, P < .001). Overall, visual acuity declined 15 or more letters from pre-implant values in 22% of affected eyes; declines were frequently associated with complications of uveitis or its treatment.There is an increasing risk of dissociation of Retisert implants during follow-up; the risk is greater with removal/exchange surgeries, but the risk of both spontaneous and surgically related events increases with longevity of the implants. In 22% of affected eyes visual acuity declined by 15 letters. In the context of eyes with moderate to severe uveitis for years, this rate is not unexpected.

The controller design and implementation of a handheld surgical robot is presented. During the treatment of human bones the robot is able to compensate un-voluntary movements of the surgeon and of the patient and to find automatically the target position of the tool. The robot system is based on a Stewart-platform actuated by linear motors and on an optical tracking system. A cascade controller provides a local position and velocity control of the motor axes and an absolute position control in the world frame. To show the feasibility of the concept, cavities are milled into polystyrene-foam, while the robot is decoupled from the test bed. For clinical demands the robot has to be improved in the static and dynamic accuracy.

This work describes the worldwide state of the art concerning the development of robot-aided operative medicine. It is based on literature-, proceedings- and internet-research. 84 robotic systems are presented briefly by describing applications workgroups, project status and reference. The examination of the international research and development in the field of robotic applications in medicine shows a wide distribution in different areas of medicine. Only a few systems can be used clincally.

Applications in robot-aided surgery are currently based on modifications of manipulators used in industrial manufacturing processes. In this paper we describe novel rotatory kinematics for a manipulator, specially developed for deployment in robot-aided surgery.The construction of the gearing mechanism used for the positioning and orientation of a linkage point is described. Forward and inverse kinematics were calculated, and a constructive solution proposed. The gearing mechanism is based on two disk systems, each of which consists of two opposing rotatable discs. The construction was designed in such a way that the linkage point can be positioned freely anywhere within the mechanism's range of motion. The kinematics thus permits an x-y-positioning via rotating movements only. The spatial arrangement of two of such disc systems permits movements in four degrees of freedom (DOF).The construction is compact, but can be further miniaturized, is flexible and manufacturing costs are low. On the basis of this mechanical concept a new, small automated manipulator for surgical application will be developed.

Drug Prescribing for Patients with Chronic Kidney Disease in General Practice: a Cross-Sectional Study

Journal Article Method an Results of Immunological Determination of Pituitary Gonadotropin Get access Paul Weiser Paul Weiser Universitäts-Frauenklinik, Münster/Westfalen, Westring 11 Search for other works by this author on: Oxford Academic Google Scholar Acta Endocrinologica (Norway), Volume 49, Issue 3_Supplement, Aug 1965, Page S120, https://doi.org/10.1530/acta.0.049S120 Published: 01 August 1965

Abstract Anwendungen in der roboterunterstützten Chirurgie basieren derzeit auf der Anpassung von Manipulatoren aus der industriellen Fertigung. Es wird in der vorliegenden Arbeit eine neuartige rotatorische Getriebekinematik für einen Manipulator beschrieben. Sie wurde speziell für den Einsatz in der roboterunterstützten Chirurgie konstruiert. Es wird der Aufbau der Getriebekinematik für die Positionierung und Ausrichtung eines Anlenkpunktes beschrieben. Die Vorwärts- und Inverskinematik wurde berechnet. Eine konstruktiver Lösungsvorschlag wird gezeigt. Das Getriebe basiert auf zwei Scheibensystemen. Jedes dieser Systeme besteht aus gegeneinander verdrehbaren Scheiben, deren Bauform und -größe so gewählt sind, daß ein Anlenkpunkt innerhalb der Bewegungsgrenzen des Getriebes frei positioniert werden kann. Die Kinematik ermöglicht somit eine x-y-Positionierung mit rein rotatorischen Bewegungen. Eine räumliche Anordnung von zwei gleichen Scheibensystemen läßt Bewegungen in vier Freiheitsgraden (DOF) zu. Das Bauprinzip erweist sich als kompakt, weiter miniaturisierbar, flexibel und günstig herzustellen. Aufbauend auf dem mechanischen Konzept, soll ein neuer kleiner automatisierter Manipulator für den operativen Einsatz entwickelt werden. Applications in robot-aided surgery are currently based on modifications of manipulators used in industrial manufacturing processes. In this paper we describe novel rotatory kinematics for a manipulator, specially developed for deployment in robot-aided surgery. The construction of the gearing mechanism used for the positioning and orientation of a linkage point is described. Forward and inverse kinematics were calculated, and a constructive solution proposed. The gearing mechanism is based on two disk systems, each of which consists of two opposing rotatable discs. The construction was designed in such a way that the linkage point can be positioned freely anywhere within the mechanism’s range of motion. The kinematics thus permits an x-y-positioning via rotating movements only. The spatial arrangement of two of such disc systems permits movements in four degrees of freedom (DOF). The construction is compact, but can be further miniaturized, is flexible and manufacturing costs are low. On the basis of this mechanical concept a new, small automated manipulator for surgical application will be developed.