Wireless Millimeter-Size Soft Climbing Robots with Omnidirectional Steerability on Tissue Surfaces.

Wirelessly actuated miniature soft robots actuated by magnetic fields that can overcome gravity by climbing soft and wet tissues are promising for accessing challenging enclosed and confined spaces with minimal invasion for targeted medical operation. However, existing designs lack the directional steerability to traverse complex terrains and perform agile medical operations. Here we propose a rod-shaped millimeter-size climbing robot that can be omnidirectionally steered with a steering angle up to 360 degrees during climbing beyond existing soft miniature robots. The design innovation includes the rod-shaped robot body, its special magnetization profile, and the spherical robot footpads, allowing directional bending of the body under external magnetic fields and out-of-plane motion of the body for delivery of medical patches. With further integrated bio-adhesives and microstructures on the footpads, we experimentally demonstrated inverted climbing of the robot on porcine gastrointestinal (GI) tract tissues and deployment of a medical patch for targeted drug delivery.

Robust endoscopic image mosaicking via fusion of multimodal estimation.

We propose an endoscopic image mosaicking algorithm that is robust to light conditioning changes, specular reflections, and feature-less scenes. These conditions are especially common in minimally invasive surgery where the light source moves with the camera to dynamically illuminate close range scenes. This makes it difficult for a single image registration method to robustly track camera motion and then generate consistent mosaics of the expanded surgical scene across different and heterogeneous environments. Instead of relying on one specialised feature extractor or image registration method, we propose to fuse different image registration algorithms according to their uncertainties, formulating the problem as affine pose graph optimisation. This allows to combine landmarks, dense intensity registration, and learning-based approaches in a single framework. To demonstrate our application we consider deep learning-based optical flow, hand-crafted features, and intensity-based registration, however, the framework is general and could take as input other sources of motion estimation, including other sensor modalities. We validate the performance of our approach on three datasets with very different characteristics to highlighting its generalisability, demonstrating the advantages of our proposed fusion framework. While each individual registration algorithm eventually fails drastically on certain surgical scenes, the fusion approach flexibly determines which algorithms to use and in which proportion to more robustly obtain consistent mosaics.

Robotic Autonomy for Magnetic Endoscope Biopsy.

Magnetically actuated endoscopes are currently transitioning in to clinical use for procedures such as colonoscopy, presenting numerous benefits over their conventional counterparts. Intelligent and easy-to-use control strategies are an essential part of their clinical effectiveness due to the un-intuitive nature of magnetic field interaction. However, work on developing intelligent control for these devices has mainly been focused on general purpose endoscope navigation. In this work, we investigate the use of autonomous robotic control for magnetic colonoscope intervention via biopsy, another major component of clinical viability. We have developed control strategies with varying levels of robotic autonomy, including semi-autonomous routines for identifying and performing targeted biopsy, as well as random quadrant biopsy. We present and compare the performance of these approaches to magnetic endoscope biopsy against the use of a standard flexible endoscope on bench-top using a colonoscopy training simulator and silicone colon model. The semi-autonomous routines for targeted and random quadrant biopsy were shown to reduce user workload with comparable times to using a standard flexible endoscope.

Active Stabilization of Interventional Tasks Utilizing a Magnetically Manipulated Endoscope.

Magnetically actuated robots have become increasingly popular in medical endoscopy over the past decade. Despite the significant improvements in autonomy and control methods, progress within the field of medical magnetic endoscopes has mainly been in the domain of enhanced navigation. Interventional tasks such as biopsy, polyp removal, and clip placement are a major procedural component of endoscopy. Little advancement has been done in this area due to the problem of adequately controlling and stabilizing magnetically actuated endoscopes for interventional tasks. In the present paper we discuss a novel model-based Linear Parameter Varying (LPV) control approach to provide stability during interventional maneuvers. This method linearizes the non-linear dynamic interaction between the external actuation system and the endoscope in a set of equilibria, associated to different distances between the magnetic source and the endoscope, and computes different controllers for each equilibrium. This approach provides the global stability of the overall system and robustness against external disturbances. The performance of the LPV approach is compared to an intelligent teleoperation control method (based on a Proportional Integral Derivative (PID) controller), on the Magnetic Flexible Endoscope (MFE) platform. Four biopsies in different regions of the colon and at two different system equilibria are performed. Both controllers are asked to stabilize the endoscope in the presence of external disturbances (i.e. the introduction of the biopsy forceps through the working channel of the endoscope). The experiments, performed in a benchtop colon simulator, show a maximum reduction of the mean orientation error of the endoscope of 45.8% with the LPV control compared to the PID controller.

Rate of and Factors Associated with Palliative Care Referral among Patients Declined for Liver Transplantation.

Background: End-stage liver disease (ESLD) is associated with high morbidity and mortality, with liver transplantation as the only existing cure. Despite reduced quality of life and limited life expectancy, referral to palliative care (PC) rarely occurs. Moreover, there is scarcity of data on the appropriate timing and type of PC intervention needed. Aim: To evaluate PC utilization and documentation in ESLD patients declined or delisted for transplant at a tertiary care medical center with a large liver transplantation program. Methods: We performed a retrospective cohort study of all patients discussed in Liver Transplant Committee (LTC) at our academic medical center between August 2018 and May 2020 in the United States. Patients declined or delisted for liver transplantation were included. Baseline demographics, model for end-stage liver disease (MELD) score, decompensation events, and reason for transplant ineligibility were recorded. The primary outcome was PC referral. Secondary outcomes included survival from LTC decision, time from LTC decision to PC referral, and code status in relation to PC referral. Results: Of 769 patients discussed at LTC, 135 were declined for transplantation. Thirty-seven (27%) received referral to PC. When adjusting for body mass index and age, MELD score of 21-30 had odds ratio (OR) of 4.5 (95% confidence interval [CI]: 1.7-12.3) and MELD score >30 had OR of 12.8 (95% CI: 3.9-47.7) for PC referral when compared with MELD score <20. When adjusting for MELD score, presence of ascites had OR of 4.6 (95% CI: 1.1-19.1) and presence of multiple complications had OR of 2.2 (95% CI: 2.2-3.8). Conclusions: Only 37 (27%) patients delisted or declined for liver transplantation were referred to PC. MELD score and degree of decompensation were important factors associated with referral. Continued exploration of these data could help guide future studies and help determine timing and criteria for PC referral.

Closed-loop control of soft continuum manipulators under tip follower actuation.

Continuum manipulators, inspired by nature, have drawn significant interest within the robotics community. They can facilitate motion within complex environments where traditional rigid robots may be ineffective, while maintaining a reasonable degree of precision. Soft continuum manipulators have emerged as a growing subfield of continuum robotics, with promise for applications requiring high compliance, including certain medical procedures. This has driven demand for new control schemes designed to precisely control these highly flexible manipulators, whose kinematics may be sensitive to external loads, such as gravity. This article presents one such approach, utilizing a rapidly computed kinematic model based on Cosserat rod theory, coupled with sensor feedback to facilitate closed-loop control, for a soft continuum manipulator under tip follower actuation and external loading. This approach is suited to soft manipulators undergoing quasi-static deployment, where actuators apply a follower wrench (i.e., one that is in a constant body frame direction regardless of robot configuration) anywhere along the continuum structure, as can be done in water-jet propulsion. In this article we apply the framework specifically to a tip actuated soft continuum manipulator. The proposed control scheme employs both actuator feedback and pose feedback. The actuator feedback is utilized to both regulate the follower load and to compensate for non-linearities of the actuation system that can introduce kinematic model error. Pose feedback is required to maintain accurate path following. Experimental results demonstrate successful path following with the closed-loop control scheme, with significant performance improvements gained through the use of sensor feedback when compared with the open-loop case.

An Origami-Based Soft Robotic Actuator for Upper Gastrointestinal Endoscopic Applications.

Soft pneumatic actuators have been explored for endoscopic applications, but challenges in fabricating complex geometry with desirable dimensions and compliance remain. The addition of an endoscopic camera or tool channel is generally not possible without significant change in the diameter of the actuator. Radial expansion and ballooning of actuator walls during bending is undesirable for endoscopic applications. The inclusion of strain limiting methods like, wound fibre, mesh, or multi-material molding have been explored, but the integration of these design approaches with endoscopic requirements drastically increases fabrication complexity, precluding reliable translation into functional endoscopes. For the first time in soft robotics, we present a multi-channel, single material elastomeric actuator with a fully corrugated design (inspired by origami); offering specific functionality for endoscopic applications. The features introduced in this design include i) fabrication of multi-channel monolithic structure of 8.5 mm diameter, ii) incorporation of the benefits of corrugated design in a single material (i.e., limited radial expansion and improved bending efficiency), iii) design scalability (length and diameter), and iv) incorporation of a central hollow channel for the inclusion of an endoscopic camera. Two variants of the actuator are fabricated which have different corrugated or origami length, i.e., 30 mm and 40 mm respectively). Each of the three actuator channels is evaluated under varying volumetric (0.5 mls-1 and 1.5 mls-1 feed rate) and pressurized control to achieve a similar bending profile with the maximum bending angle of 150°. With the intended use for single use upper gastrointestinal endoscopic application, it is desirable to have linear relationships between actuation and angular position in soft pneumatic actuators with high bending response at low pressures; this is where the origami actuator offers contribution. The soft pneumatic actuator has been demonstrated to achieve a maximum bending angle of 200° when integrated with manually driven endoscope. The simple 3-step fabrication technique produces a complex origami pattern in a soft robotic structure, which promotes low pressure bending through the opening of the corrugation while retaining a small diameter and a central lumen, required for successful endoscope integration.

Guidelines for Robotic Flexible Endoscopy at the Time of COVID-19.

Flexible endoscopy involves the insertion of a long narrow flexible tube into the body for diagnostic and therapeutic procedures. In the gastrointestinal (GI) tract, flexible endoscopy plays a major role in cancer screening, surveillance, and treatment programs. As a result of gas insufflation during the procedure, both upper and lower GI endoscopy procedures have been classified as aerosol generating by the guidelines issued by the respective societies during the COVID-19 pandemic-although no quantifiable data on aerosol generation currently exists. Due to the risk of COVID-19 transmission to healthcare workers, most societies halted non-emergency and diagnostic procedures during the lockdown. The long-term implications of stoppage in cancer diagnoses and treatment is predicted to lead to a large increase in preventable deaths. Robotics may play a major role in this field by allowing healthcare operators to control the flexible endoscope from a safe distance and pave a path for protecting healthcare workers through minimizing the risk of virus transmission without reducing diagnostic and therapeutic capacities. This review focuses on the needs and challenges associated with the design of robotic flexible endoscopes for use during a pandemic. The authors propose that a few minor changes to existing platforms or considerations for platforms in development could lead to significant benefits for use during infection control scenarios.

Magnetic flexible endoscope for colonoscopy: an initial learning curve analysis.

Background and study aims Colonoscopy is a technically challenging procedure that requires extensive training to minimize discomfort and avoid trauma due to its drive mechanism. Our academic team developed a magnetic flexible endoscope (MFE) actuated by magnetic coupling under supervisory robotic control to enable a front-pull maneuvering mechanism, with a motion controller user interface, to minimize colon wall stress and potentially reduce the learning curve. We aimed to evaluate this learning curve and understand the user experience. Methods Five novices (no endoscopy experience), five experienced endoscopists, and five experienced MFE users each performed 40 trials on a model colon using 1:1 block randomization between a pediatric colonoscope (PCF) and the MFE. Cecal intubation (CI) success, time to cecum, and user experience (NASA task load index) were measured. Learning curves were determined by the number of trials needed to reach minimum and average proficiency-defined as the slowest average CI time by an experienced user and the average CI time by all experienced users, respectively. Results MFE minimum proficiency was achieved by all five novices (median 3.92 trials) and five experienced endoscopists (median 2.65 trials). MFE average proficiency was achieved by four novices (median 14.21 trials) and four experienced endoscopists (median 7.00 trials). PCF minimum and average proficiency levels were achieved by only one novice. Novices' perceived workload with the MFE significantly improved after obtaining minimum proficiency. Conclusions The MFE has a short learning curve for users with no prior experience-requiring relatively few attempts to reach proficiency and at a reduced perceived workload.

Enteral Stents for Malignant Gastric Outlet Obstruction: Low Reintervention Rates for Obstruction due to Pancreatic Adenocarcinoma Versus Other Etiologies.

BACKGROUND AND AIM: Enteral stents (ES) have emerged as first-line therapy for the treatment of malignant gastric outlet obstruction (GOO). Stent occlusion arising from tissue ingrowth may require endoscopic or surgical reintervention. The objective of this study was to compare rates of reintervention following palliative ES for patients with GOO due to pancreatic adenocarcinoma (PDAC) versus other malignant etiologies. METHODS: Patients who had undergone ES for palliation of malignant GOO between 2009 and 2018 were retrospectively identified and demographic, clinical, and procedural data were collected. Primary outcome was procedural reintervention for recurrent symptomatic GOO following ES placement. RESULTS: Forty-three patients were included in the study cohort. 62.8% (27/43) of patients had PDAC while 37.2% (16/43) of patients had other malignant etiologies. 11.6% (5/43) of patients were alive at follow-up. Thirty-day and 90-day mortality rates were 22.8% and 70.7% for PDAC and 25% and 56.3% for other malignant etiologies, respectively. Seven patients required reintervention for symptomatic GOO: 14.3% (1/7) had PDAC and 85.7% (6/7) had GOO due to other malignancy (P < .01). Ninety-six percent (26/27) of patients with PDAC required no further intervention for GOO prior to death or end of follow-up. On multivariate analysis, patients with PDAC were significantly less likely to require reintervention than patients with other malignant etiologies (OR 0.064, 95% CI 0.01-0.60). CONCLUSION: ES offer durable symptom palliation without requirement for reintervention for the overwhelming majority of patients with malignant GOO due to PDAC. Reintervention rates are higher following ES placement for GOO due to other malignant etiologies and future study may be needed to define the optimal palliative intervention for this group of patients.

The impact of distraction minimization on endoscopic mentoring and performance.

Background and study aims Endoscopic mentoring requires active attention by the preceptor. Unfortunately, sources of distraction are abundant during endoscopic precepting. The impact of distraction minimization on endoscopic mentoring and performance is unknown. Methods Fellow and attending preceptors were paired and randomized in a prospective crossover design to perform esophagogastroduodenoscopy (EGD) and/or colonoscopy in either a "distraction minimization" (DM) or a "standard" (S) room. Cell phones, pagers, music, and computers were not permitted in DM rooms. S rooms operated under typical conditions. Fellows and attendings then completed a survey. The primary outcome was fellow satisfaction with mentoring experience (visual analogue scale: 0 = min,100 = max). Additional fellow outcomes included satisfaction of attending attentiveness, identifying landmarks, communication, and distractedness; attending outcomes included satisfaction with mentoring, attentiveness, communication, and distractedness. Endoscopic performance measures included completion of EGD, cecal intubation rate, cecal intubation time, withdrawal time, total procedure time, attending assistance, and polyp detection rate. A paired t -test was used to compare mean differences (MD) between rooms; significance set at P  < 0.05. Results Eight fellows and seven attendings completed 164 procedures. Despite a trend toward less distraction between rooms (DM = 12.5 v. S = 18.3, MD =  4.1, P  = 0.17), there was no difference in fellow satisfaction with training/mentoring (DM = 93, S = 93, MD = -0.04, P  = 0.97), attentiveness (DM = 95, S = 92, MD = 0.86, P  = 0.77), identifying pathology/landmarks (DM = 94, S = 94, MD = -1.72, P  = 0.56), or communication (DM = 95, S = 95,MD = 1.0, P  = 0.37). Similarly, there was no difference between rooms for any attending outcome measures or performance metrics. Conclusions DM did not improve perceived quality of endoscopic mentoring or performance for fellows or attendings; however, reduced distraction may improve attending engagement/availability.

Enabling the future of colonoscopy with intelligent and autonomous magnetic manipulation.

Early diagnosis of colorectal cancer significantly improves survival. However, over half of cases are diagnosed late due to demand exceeding the capacity for colonoscopy - the "gold standard" for screening. Colonoscopy is limited by the outdated design of conventional endoscopes, associated with high complexity of use, cost and pain. Magnetic endoscopes represent a promising alternative, overcoming drawbacks of pain and cost, but struggle to reach the translational stage as magnetic manipulation is complex and unintuitive. In this work, we use machine vision to develop intelligent and autonomous control of a magnetic endoscope, for the first time enabling non-expert users to effectively perform magnetic colonoscopy in-vivo. We combine the use of robotics, computer vision and advanced control to offer an intuitive and effective endoscopic system. Moreover, we define the characteristics required to achieve autonomy in robotic endoscopy. The paradigm described here can be adopted in a variety of applications where navigation in unstructured environments is required, such as catheters, pancreatic endoscopy, bronchoscopy, and gastroscopy. This work brings alternative endoscopic technologies closer to the translational stage, increasing availability of early-stage cancer treatments.

A Compression Valve for Sanitary Control of Fluid-Driven Actuators.

With significant research focused on integrating robotics into medical devices, sanitary control of pressurizing fluids in a precise, accurate and customizable way is highly desirable. Current sanitary flow control methods include pinch valves which clamp the pressure line locally to restrict fluid flow; resulting in damage and variable flow characteristics over time. This paper presents a sanitary compression valve based on an eccentric clamping mechanism. The proposed valve distributes clamping forces over a larger area, thereby reducing the plastic deformation and associated influence on flow characteristic. Using the proposed valve, significant reductions in plastic deformation (up to 96%) and flow-rate error (up to 98%) were found, when compared with a standard pinch valve. Additionally, an optimization strategy presents a method for improving linearity and resolution over the working range to suit specific control applications. The valve efficacy has been evaluated through controlled testing of a water jet propelled low-cost endoscopic device. In this case, use of the optimized valve shows a reduction in the average orientation error and its variation, resulting in smoother movement of the endoscopic tip when compared to alternative wet and dry valve solutions. The presented valve offers a customizable solution for sanitary control of fluid driven actuators.