ABSTRACT
High-resolution real-time intraocular imaging of retina at the cellular level is very challenging due to the vulnerable and confined space within the eyeball as well as the limited availability of appropriate modalities. A probe-based confocal laser endomicroscopy (pCLE) system, can be a potential imaging modality for improved diagnosis. The ability to visualize the retina at the cellular level could provide information that may predict surgical outcomes. The adoption of intraocular pCLE scanning is currently limited due to the narrow field of view and the micron-scale range of focus. In the absence of motion compensation, physiological tremors of the surgeons' hand and patient movements also contribute to the deterioration of the image quality. Therefore, an image-based hybrid control strategy is proposed to mitigate the above challenges. The proposed hybrid control strategy enables a shared control of the pCLE probe between surgeons and robots to scan the retina precisely, with the absence of hand tremors and with the advantages of an image-based auto-focus algorithm that optimizes the quality of pCLE images. The hybrid control strategy is deployed on two frameworks - cooperative and teleoperated. Better image quality, smoother motion, and reduced workload are all achieved in a statistically significant manner with the hybrid control frameworks.
ABSTRACT
In this paper, a novel semi-autonomous control framework is presented for enabling probe-based confocal laser endomicroscopy (pCLE) scan of the retinal tissue. With pCLE, retinal layers such as nerve fiber layer (NFL) and retinal ganglion cell (RGC) can be scanned and characterized in real-time for an improved diagnosis and surgical outcome prediction. However, the limited field of view of the pCLE system and the micron-scale optimal focus distance of the probe, which are in the order of physiological hand tremor, act as barriers to successful manual scan of retinal tissue. Therefore, a novel sensorless framework is proposed for real-time semi-autonomous endomicroscopy scanning during retinal surgery. The framework consists of the Steady-Hand Eye Robot (SHER) integrated with a pCLE system, where the motion of the probe is controlled semi-autonomously. Through a hybrid motion control strategy, the system autonomously controls the confocal probe to optimize the sharpness and quality of the pCLE images, while providing the surgeon with the ability to scan the tissue in a tremor-free manner. Effectiveness of the proposed architecture is validated through experimental evaluations as well as a user study involving 9 participants. It is shown through statistical analyses that the proposed framework can reduce the work load experienced by the users in a statistically-significant manner, while also enhancing their performance in retaining pCLE images with optimized quality.
ABSTRACT
OBJECTIVES/HYPOTHESIS: To evaluate gains in microlaryngeal precision achieved by using a novel robotic "steady hand" microsurgery platform in performing simulated phonosurgical tasks. STUDY DESIGN: Crossover comparative study of surgical performance and descriptive analysis of surgeon feedback. METHODS: A novel robotic ear, nose, and throat microsurgery system (REMS) was tested in simulated phonosurgery. Participants navigated a 0.4-mm-wide microlaryngeal needle through spirals of varying widths, both with and without robotic assistance. Fail time (time the needle contacted spiral edges) was measured, and statistical comparison was performed. Participants were surveyed to provide subjective feedback on the REMS. RESULTS: Nine participants performed the task at three spiral widths, yielding 27 paired testing conditions. In 24 of 27 conditions, robot-assisted performance was better than unassisted; five trials were errorless, all achieved with the robot. Paired analysis of all conditions revealed fail time of 0.769 ± 0.568 seconds manually, improving to 0.284 ± 0.584 seconds with the robot (P = .003). Analysis of individual spiral sizes showed statistically better performance with the REMS at spiral widths of 2 mm (0.156 ± 0.226 seconds vs. 0.549 ± 0.545 seconds, P = .019) and 1.5 mm (0.075 ± 0.099 seconds vs. 0.890 ± 0.518 seconds, P = .002). At 1.2 mm, all nine participants together showed similar performance with and without robotic assistance (0.621 ± 0.923 seconds vs. 0.868 ± 0.634 seconds, P = .52), though subgroup analysis of five surgeons most familiar with microlaryngoscopy showed statistically better performance with the robot (0.204 ± 0.164 seconds vs. 0.664 ± 0.354 seconds, P = .036). CONCLUSIONS: The REMS is a novel platform with potential applications in microlaryngeal phonosurgery. Further feasibility studies and preclinical testing should be pursued as a bridge to eventual clinical use. LEVEL OF EVIDENCE: NA. Laryngoscope, 128:126-132, 2018.
