Robotic Assistance for Intraocular Microsurgery: Challenges and Perspectives

BIOMECHANICAL CONSIDERATIONS FOR OPTIMISING SUBRETINAL INJECTIONS

Subretinal injection is the preferred delivery technique for various novel ocular therapies and is widely used because of its precision and efficient delivery of gene and cell therapies; however, choosing an injection point and defining delivery parameters to target a specified retinal location and area is an inexact science. We provide an overview of the key factors that play important roles during subretinal injections to refine the technique, enhance patient outcomes, and minimise risks. We describe the role of anatomical and physical variables that affect subretinal bleb propagation and shape and their impact on retinal integrity. We highlight the risks associated with subretinal injections and consider strategies to mitigate reflux and retinal trauma. Finally, we explore the emerging field of robotic assistance in improving intraocular manouvrability and precision to facilitate the injection procedure.

A Lightweight and Affordable Wearable Haptic Controller for Robot-Assisted Microsurgery

In robot-assisted microsurgery (RAMS), surgeons often face the challenge of operating with minimal feedback, particularly lacking in haptic feedback. However, most traditional desktop haptic devices have restricted operational areas and limited dexterity. This report describes a novel, lightweight, and low-budget wearable haptic controller for teleoperated microsurgical robotic systems. We designed a wearable haptic interface entirely made using off-the-shelf material-PolyJet Photopolymer, fabricated using liquid and solid hybrid 3D co-printing technology. This interface was designed to resemble human soft tissues and can be wrapped around the fingertips, offering direct contact feedback to the operator. We also demonstrated that the device can be easily integrated with our motion tracking system for remote microsurgery. Two motion tracking methods, marker-based and marker-less, were compared in trajectory-tracking experiments at different depths to find the most effective motion tracking method for our RAMS system. The results indicate that within the 4 to 8 cm tracking range, the marker-based method achieved exceptional detection rates. Furthermore, the performance of three fusion algorithms was compared to establish the unscented Kalman filter as the most accurate and reliable. The effectiveness of the wearable haptic controller was evaluated through user studies focusing on the usefulness of haptic feedback. The results revealed that haptic feedback significantly enhances depth perception for operators during teleoperated RAMS.

A Novel Electromagnetic Driving System for 5-DOF Manipulation in Intraocular Microsurgery

This work presents a novel electromagnetic driving system that consists of eight optimized electromagnets arranged in an optimal configuration and employs a control framework based on an active disturbance rejection controller (ADRC) and virtual boundary. The optimal system configuration enhances the system's compatibility with other ophthalmic surgical instruments, while also improving its capacity to generate magnetic force in the vertical direction. Besides, the optimal electromagnet parameters provide a superior comprehensive performance on magnetic field generation capacity and thermal power. Hence, the presented design achieves a stronger capacity for sustained work. Furthermore, the ADRC controller effectively monitors and further compensates the total disturbance as well as gravity to enhance the system's robustness. Meanwhile, the implementation of virtual boundaries substantially enhances interactive security via collision avoidance. The magnetic and thermal performance tests have been performed on the electromagnet to verify the design optimization. The proposed electromagnet can generate a superior magnetic field of 2.071 mT at a distance of 65 mm with an applied current of 1 A. Moreover, it demonstrates minimal temperature elevation from room temperature (25 °C) to 46 °C through natural heat dissipation in 3 h, thereby effectively supporting prolonged magnetic manipulation of intraocular microsurgery. Furthermore, trajectory tracking experiments with disturbances have been performed in a liquid environment similar to the practical ophthalmic surgery scenarios, to verify the robustness and security of the presented control framework. The maximum root mean square (RMS) error of performance tests in different operation modes remains 35.8 μm, providing stable support for intraocular microsurgery.

Soft Tissue Robotic Assisted Orbital Surgery Using da Vinci SP: A Cadaveric Experience

PURPOSE

Robotic surgical techniques have transformed many surgical specialties however robotic techniques and applications have been much more limited in ophthalmology. This study aims to evaluate the feasibility of robotic assisted orbital surgery using a single-port novel robotic platform, the da Vinci SP.

METHODS

A series of orbital procedures were performed in cadaveric specimens utilizing the da Vinci SP robotic system. The procedures performed included lacrimal gland dissection and biopsy, medial and lateral orbital wall dissections, enucleation, and lid-sparing orbital exenteration. Successful completion of each procedure was defined by the operating surgeon and was considered the primary outcome and marker of feasibility.

RESULTS

Seven cadaveric procedures were performed in 3 cadaveric specimens. All 7 procedures were completed successfully without complication. Setup optimization occurred throughout the study and setup and operative times were acceptable. Three instrument arms and 1 endoscope were utilized throughout the study allowing 3 arm operating and dynamic retraction. Instrument size was found to limit surgical access and precision particular at the orbital apex.

CONCLUSIONS

This preclinical study demonstrates that the da Vinci SP can be utilized within the orbit and is feasible for several applications. Robotic surgical systems offer significant advantages over conventional techniques and should be embraced. However, current commercially available robotic platforms are not optimized for the orbit and have their limitations although they may be suitable for some clinical applications.

Microsurgery Robots: Applications, Design, and Development

Microsurgical techniques have been widely utilized in various surgical specialties, such as ophthalmology, neurosurgery, and otolaryngology, which require intricate and precise surgical tool manipulation on a small scale. In microsurgery, operations on delicate vessels or tissues require high standards in surgeons' skills. This exceptionally high requirement in skills leads to a steep learning curve and lengthy training before the surgeons can perform microsurgical procedures with quality outcomes. The microsurgery robot (MSR), which can improve surgeons' operation skills through various functions, has received extensive research attention in the past three decades. There have been many review papers summarizing the research on MSR for specific surgical specialties. However, an in-depth review of the relevant technologies used in MSR systems is limited in the literature. This review details the technical challenges in microsurgery, and systematically summarizes the key technologies in MSR with a developmental perspective from the basic structural mechanism design, to the perception and human-machine interaction methods, and further to the ability in achieving a certain level of autonomy. By presenting and comparing the methods and technologies in this cutting-edge research, this paper aims to provide readers with a comprehensive understanding of the current state of MSR research and identify potential directions for future development in MSR.

Eye-mounting goggles to bridge the gap between benchtop experiments and in vivo robotic eye surgery

A variety of robot-assisted surgical systems have been proposed to improve the precision of eye surgery. Evaluation of these systems has typically relied on benchtop experiments with artificial or enucleated eyes. However, this does not properly account for the types of head motion that are common among patients undergoing eye surgery, which a clinical robotic system will encounter. In vivo experiments are clinically realistic, but they are risky and thus require the robotic system to be at a sufficiently mature state of development. In this paper, we describe a low-cost device that enables an artificial or enucleated eye to be mounted to standard swim goggles worn by a human volunteer to enable more realistic evaluation of eye-surgery robots after benchtop studies and prior to in vivo studies. The mounted eye can rotate about its center, with a rotational stiffness matching that of an anesthetized patient's eye. We describe surgeon feedback and technical analyses to verify that various aspects of the design are sufficient for simulating a patient's eye during surgery.