Comparison of robot-assisted vitreoretinal surgery and manual surgery in different preclinical settings: a randomized trial.

Background: Progress in the field of surgical robotics has the potential to allow surgeons to reduce the limitations of human hands and has substantially improved the dexterity and accuracy of surgery. This study aimed to compare robot-assisted vitreoretinal surgery with manual surgery in a simulated setting involving donor porcine eyes. Methods: A randomized controlled trial was conducted involving 10 experienced vitreoretinal experts and 10 residents. Participants were randomized to start with either manual or robot-assisted surgery (n=5 in each group). Participants completed 3 tests consisting of 2 vitreoretinal modules on a virtual-reality simulator and microcannulation in donor porcine eyes. The primary outcome measures were as follows: test completion time, surgical accuracy and tremor control provided by the simulator, and the feasibility of microcannulation in donor porcine eyes. Results: Robot-assisted surgery supported better accuracy and tremor control than manual surgery for vitreoretinal experts (P=0.028 and P=0.002, respectively) and residents (P=0.025 and P<0.001, respectively). Residents improved their microcannulation performance with the assistance of the robot (P=0.038) to a level comparable to that of experts (P=0.49). Robot-assisted surgery was less time-efficient than manual surgery for both residents (P<0.001) and vitreoretinal experts (P<0.001). Conclusions: Compared with manual surgery, robot-assisted vitreoretinal surgery improves the stability of instrument handling and the accuracy of surgery. Robot-assisted surgeries have the potential to shorten the learning curve for residents and improve surgical performance.

Intelligent cataract surgery supervision and evaluation via deep learning.

PURPOSE: To assess the performance of a deep learning (DL) algorithm for evaluating and supervising cataract extraction using phacoemulsification with intraocular lens (IOL) implantation based on cataract surgery (CS) videos. MATERIALS AND METHODS: DeepSurgery was trained using 186 standard CS videos to recognize 12 CS steps and was validated in two datasets that contained 50 and 21 CS videos, respectively. A supervision test including 50 CS videos was used to assess the DeepSurgery guidance and alert function. In addition, a real-time test containing 54 CSs was used to compare the DeepSurgery grading performance to an expert panel and residents. RESULTS: DeepSurgery achieved stable performance for all 12 recognition steps, including the duration between two pairs of adjacent steps in internal validation with an ACC of 95.06% and external validations with ACCs of 88.77% and 88.34%. DeepSurgery also recognized the chronology of surgical steps and alerted surgeons to order of incorrect steps. Six main steps are automatically and simultaneously quantified during the evaluation process (centesimal system). In a real-time comparative test, the DeepSurgery step recognition performance was robust (ACC of 90.30%). In addition, DeepSurgery and an expert panel achieved comparable performance when assessing the surgical steps (kappa ranged from 0.58 to 0.77). CONCLUSIONS: DeepSurgery represents a potential approach to provide a real-time supervision and an objective surgical evaluation system for routine CS and to improve surgical outcomes.

Measurement of phonation threshold power in normal and disordered voice production.

OBJECTIVES: Phonation threshold pressure (PTP) and phonation threshold flow (PTF) are useful aerodynamic parameters, but each is sensitive to different disorders. A single comprehensive aerodynamic parameter sensitive to a variety of disorders might be beneficial in quantitative voice assessment. We performed the first study of phonation threshold power (PTW) in human subjects. METHODS: PTP and PTF were measured in 100 normal subjects, 19 subjects with vocal fold immobility, and 94 subjects with a benign mass lesion. PTW was calculated from these two parameters. In 41 subjects with a polyp, measurements were obtained before and after excision. Receiver operating characteristic (ROC) analysis was used to determine the ability of the three parameters to distinguish between controls and disordered groups. RESULTS: The PTW (p < 0.001), PTP (p < 0.001), and PTF (p < 0.001) were different among the three groups. All parameters decreased after polyp excision. PTW had the highest area under the ROC curve for all analyses. CONCLUSIONS: PTW is sensitive to the presence of mass lesions and vocal fold mobility disorders. Additionally, changes in PTW can be observed after excision of mass lesions. PTW could be a useful parameter to describe the aerodynamic inputs to voice production.

[Role of aerodynamic parameters in voice function assessment].

OBJECTIVE: To investigate the application and significance of aerodynamic parameters in voice function assessment. METHODS: The phonatory aerodynamic system (PAS) was used to collect aerodynamic parameters from subjects with normal voice, vocal fold polyp, vocal fold cyst, and vocal fold immobility. Multivariate statistical analysis was used to compare measurements across groups. RESULTS: Phonation threshold flow (PTF), mean flow rate (MFR), maximum phonation time (MPT), and glottal resistance (GR) in one hundred normal subjects were significantly affected by sex (P < 0.05), while phonation threshold pressure (PTP), subglottal pressure (SGP), and vocal efficiency (VE) were not (P > 0.05). PTP, PTF, MFR, SGP, and MPT were significantly different between normal voice and voice disorders (P < 0.01), and there were no significant differences among the three disorders (P > 0.05). Receiver operating characteristic (ROC) analysis found that PTP, PTF, SGP, MFR, MPT, and VE in one hundred thirteen voice dis orders had similar diagnostic utility (P < 0.01), with PTP exhibiting the highest area under the curve. The aerodynamic parameters of the three degrees of voice dysfunction due to vocal cord polyps were compared and found to have no significant differences (P > 0.05). PTP, PTF, MFR, SGP and MPT in forty one patients with vocal polyps were significantly different after surgical resection of vocal cord polyps (P < 0.01). CONCLUSION: The aerodynamic parameters can objectively and effectively evaluate the variations of vocal function, and have good auxiliary diagnostic value.

Destruction of nitrotoluenes in wastewater by Electro-Fenton oxidation.

Electrolytic degradation of dinitrotoluenes (DNTs) and 2,4,6-trinitrotoluene (TNT) in wastewater was conducted by Electro-Fenton's reagents. The batch-wise experiments were carried out to elucidate the influence of various operating variables on the electrolytic behavior, including electrode potential, oxygen dosage, electrolytic temperature, acidity of wastewater and dosage of ferrous ions. It deserves to note that the nitrotoluenes contained could be completely decomposed by Electro-Fenton's reagents, wherein hydrogen peroxide was in situ generated from cathodic reduction of oxygen, supplied mainly by anodic oxidation of water. During the electrochemical process, the influence of electrolytic temperature on the degradation of nitrotoluenes is the most significant, followed by electrode potential, acidity of wastewater and oxygen dosage. Based on the spectra analyzed by gas chromatograph/mass spectrometer (GC/MS), it is proposed that initial denitration of 2,4-DNT and/or 2,6-DNT gives rise to formation of o-mononitrotoluene, which undergoes the cleavage of nitro group into toluene, followed by oxidation of methyl group to benzoic acid and subsequent decarboxylation. It is believed that the electrolytic method established is potentially applied to dispose wastewater from toluene nitration processes in practice.