[Intraoperative optical coherence tomography in explorative vitrectomy in patients with vitreous haemorrhage-a case series]. / Intraoperative optische Kohärenztomographie bei explorativer Vitrektomie an Patienten mit Glaskörperblutung ­ eine Fallserie.

BACKGROUND: High-resolution spectral domain optical coherence tomography (SD-OCT) is a gold standard technique for diagnosis, management and monitoring of patients with vitreoretinal diseases. Preoperative diagnostics for evaluation of intraocular and retinal status in patients with vitreous haemorrhage are limited, thus final therapeutic decisions can only be made during explorative vitrectomy. We evaluated the use of intraoperative SD-OCT (iSD-OCT) as a real-time additional diagnostic tool during explorative vitrectomy in patients with vitreous haemorrhage. METHODS: We report on 9 patients (11 eyes) with vitreous haemorrhage. Preoperative ultrasound was performed to evaluate intraocular status. Subsequently, an explorative 23G pars plana vitrectomy was performed under visualisation with the OPMI Lumera 700 surgical microscope (Carl Zeiss Meditec, Jena, Germany) equipped with a fully integrated iSD-OCT device (Rescan 700, Carl Zeiss Meditec, Jena, Germany) as a real-time diagnostic tool. RESULTS: In all patients, intraoperative iSD-OCT allowed real-time evaluation of the preretinal, intraretinal and subretinal structures in addition to the intraoperative en face image. The further surgical strategy, i. e. necessity for peeling of epiretinal membranes (ERM) or of the inner limiting membrane (ILM), application of intravitreal medication and selection of the appropriate tamponade, was based on and optimised according to the iSD-OCT images. CONCLUSION: Intraoperative iSD-OCT is highly useful as an additional intraoperative diagnostic tool in patients with vitreous haemorrhage. In addition to the en face microscope image, it facilitates intraoperative real-time diagnosis and aids therapeutic decision-making during surgery.

A targeted drug delivery platform for assisting retinal surgeons for treating Age-related Macular Degeneration (AMD).

In this paper we present our latest robotic setup, which has been modified for sub-retinal interventions. The setup consists of: 1) sub-retinal micro cannula with automatic pump; 2) Micromanipulator; 3) patient fixation mechanism and 4) clinically compatible workstation. The primary objective of this work is to allow ophthalmologists to improve administration of substances such as drugs, stem-cells and gene cargos to their desired targets in the sub-retinal microstructures. Such a delivery method will enable effective treatment of Age-related Macular Degeneration (AMD). AMD is the leading cause of blindness in developed countries and as yet there is no efficient treatment. To validate the precision of the system a successful targeted delivery scenario with the proposed setup and using an intra-operative OCT integrated microscope in a clinical environment is presented in this paper.

Graphical user interface for a robotic workstation in a surgical environment.

Surgery using a robotic system has proven to have significant potential but is still a highly challenging task for the surgeon. An eye surgery assistant has been developed to eliminate the problem of tremor caused by human motions endangering the outcome of ophthalmic surgery. In order to exploit the full potential of the robot and improve the workflow of the surgeon, providing the ability to change control parameters live in the system as well as the ability to connect additional ancillary systems is necessary. Additionally the surgeon should always be able to get an overview over the status of all systems with a quick glance. Therefore a workstation has been built. The contribution of this paper is the design and the implementation of an intuitive graphical user interface for this workstation. The interface has been designed with feedback from surgeons and technical staff in order to ensure its usability in a surgical environment. Furthermore, the system was designed with the intent of supporting additional systems with minimal additional effort.

Haptic interface for robot-assisted ophthalmic surgery.

Vitreo-retinal surgery is challenging, as delicate structures have to be manipulated. Eliminating tremor caused by human motions when doing micromanipulation can therefore improve the outcome of such an intervention. An eye surgery robot has been built to overcome this problem. The contribution of this paper is the design of a telemanipulation setup for the robotic system. A telemanipulation setup using a haptic device featuring force feedback as a user interface for controlling a hybrid parallel-serial micromanipulator is designed and developed. The position error control scheme is chosen and different control modes are provided. The output forces of the haptic device are analyzed. The system allows the surgeon to perform precise and comfortable micromanipulation. Nevertheless a way to provide more meaningful force feedback still has to be found.

The introduction of a new robot for assistance in ophthalmic surgery.

This paper introduces the design and development of a new robotic system to assist surgeons performing ophthalmic surgeries. The robot itself is very compact and similar to an average human hand in size. Its primary application is intraocular micromanipulation in order to overcome the existing challenges in treatment of diseases like Retinal Vein Occlusion (RVO). The novel hybrid mechanism designed for this robot allows microscale motions and is stable in the presence of vibrations common in operation room (OR). The robotic system can be easily integrated into standard operation rooms and does not require modification of conventional surgical tools. This compact microsurgical system is suitable for mounting on the patient's head and thereby, solves the problem of patient motion. The compatibility of the robotic system with a real world surgical setup was evaluated and confirmed in this work.

Phenol-containing macrocyclic diamides as new catalysts in the highly regioselective conversion of epoxides to beta-hydroxy thiocyanates.

The regioselective ring-opening reactions of some epoxides with ammonium thiocyanate in the presence of a series of new phenol-containing macrocyclic diamides and also dibenzo-18-crown-6-, 18-crown-6-, benzo-15-crown-5-, and pyridine-containing macrocyclic diamide have been studied. The epoxides were subject to cleavage by NH(4)SCN in the presence of these catalysts under mild reaction conditions in various aprotic solvents. In this study, reagents and conditions have been discovered with which the individual beta-hydroxy thiocyanates can be synthesized in high yield and with more than 90% regioselectivity. The results can be discussed in terms of a four-step mechanism: (1) formation of complex between catalyst and NH(4)SCN, (2) release of SCN(-) nucleophile from the complex, (3) reaction of the active nucleophile at the less sterically hindered site in the epoxide, and (4) regeneration of catalyst. The major advantages of this method are as follows: (1) high regioselectivity, (2) simple regeneration of catalyst, (3) its reuse through several cycles without a decrease in activity, and (4) ease of workup of the reaction.