Robotic control of a traditional flexible endoscope for therapy

A generic scope actuation system for flexible endoscopes

BACKGROUND

A scope actuation system assists a surgeon in steering a scope for navigating an operative field during an interventional or diagnostic procedure. Each system is tailored for a specific surgical procedure. The development of a generic scope actuation system could assist various laparoscopic and endoscopic procedures. This has the potential to reduce the deployment and maintenance costs for a hospital, making it more accessible for clinical usage.

METHODS

A modular actuation system (for maneuvering rigid laparoscopes) was adapted to enable incorporation of flexible endoscopes. The design simplifies the installation and disassembly processes. User studies were conducted to assess the ability of the system to focus onto a diagnostic area, and to navigate during a simulated esophagogastroduodenoscopy procedure. During the studies, the endoscope was maneuvered with (robotic mode) and without (manual mode) the actuation system to navigate the endoscope's focus on a predefined track.

RESULTS

Results show that the robotic mode performed better than the manual mode on all the measured performance parameters including (a) the total duration to traverse a track, (b) the percentage of time spent outside a track while traversing, and (c) the number of times the scope focus shifts outside the track. Additionally, robotic mode also reduced the perceived workload based on the NASA-TLX scale.

CONCLUSIONS

The proposed scope actuation system enhances the maneuverability of flexible endoscopes. It also lays the groundwork for future development of modular and generic scope assistant systems that can be used in both laparoscopic and endoscopic procedures.

A robotic system for solo surgery in flexible ureteroscopy: development and evaluation with clinical users

PURPOSE

The robotic system CoFlex for kidney stone removal via flexible ureteroscopy (fURS) by a single surgeon (solo surgery, abbreviated SSU) is introduced. It combines a versatile robotic arm and a commercially available ureteroscope to enable gravity compensation and safety functions like virtual walls. The haptic feedback from the operation site is comparable to manual fURS, as the surgeon actuates all ureteroscope DoF manually.

METHODS

The system hardware and software as well as the design of an exploratory user study on the simulator model with non-medical participants and urology surgeons are described. For each user study task both objective measurements (e.g., completion time) and subjective user ratings of workload (using the NASA-TLX) and usability (using the System Usability Scale SUS) were obtained.

RESULTS

CoFlex enabled SSU in fURS. The implemented setup procedure resulted in an average added setup time of 341.7 ± 71.6 s, a NASA-TLX value of 25.2 ± 13.3 and a SUS value of 82.9 ± 14.4. The ratio of inspected kidney calyces remained similar for robotic (93.68 %) and manual endoscope guidance (94.74 %), but the NASA-TLX values were higher (58.1 ± 16.0 vs. 48.9 ± 20.1) and the SUS values lower (51.5 ± 19.9 vs. 63.6 ± 15.3) in the robotic scenario. SSU in the fURS procedure increased the overall operation time from 1173.5 ± 355.7 s to 2131.0 ± 338.0 s, but reduced the number of required surgeons from two to one.

CONCLUSIONS

The evaluation of CoFlex in a user study covering a complete fURS intervention confirmed the technical feasibility of the concept and its potential to reduce surgeon working time. Future development steps will enhance the system ergonomics, minimize the users' physical load while interacting with the robot and exploit the logged data from the user study to optimize the current fURS workflow.

User interfaces for actuated scope maneuvering in surgical systems: a scoping review

Background

A variety of human computer interfaces are used by robotic surgical systems to control and actuate camera scopes during minimally invasive surgery. The purpose of this review is to examine the different user interfaces used in both commercial systems and research prototypes.

Methods

A comprehensive scoping review of scientific literature was conducted using PubMed and IEEE Xplore databases to identify user interfaces used in commercial products and research prototypes of robotic surgical systems and robotic scope holders. Papers related to actuated scopes with human–computer interfaces were included. Several aspects of user interfaces for scope manipulation in commercial and research systems were reviewed.

Results

Scope assistance was classified into robotic surgical systems (for multiple port, single port, and natural orifice) and robotic scope holders (for rigid, articulated, and flexible endoscopes). Benefits and drawbacks of control by different user interfaces such as foot, hand, voice, head, eye, and tool tracking were outlined. In the review, it was observed that hand control, with its familiarity and intuitiveness, is the most used interface in commercially available systems. Control by foot, head tracking, and tool tracking are increasingly used to address limitations, such as interruptions to surgical workflow, caused by using a hand interface.

Conclusion

Integrating a combination of different user interfaces for scope manipulation may provide maximum benefit for the surgeons. However, smooth transition between interfaces might pose a challenge while combining controls.

A Three-Limb Teleoperated Robotic System with Foot Control for Flexible Endoscopic Surgery

Flexible endoscopy requires a lot of skill to manipulate both the endoscope and the associated instruments. In most robotic flexible endoscopic systems, the endoscope and instruments are controlled separately by two operators, which may result in communication errors and inefficient operation. Our solution is to enable the surgeon to control both the endoscope and the instruments. Here, we present a novel tele-operation robotic endoscopic system commanded by one operator using the continuous and simultaneous movements of their two hands and one foot. This 13-degree-of-freedom (DoF) system integrates a foot-controlled robotic flexible endoscope and two hand-controlled robotic endoscopic instruments, a robotic grasper and a robotic cauterizing hook. A dedicated foot-interface transfers the natural foot movements to the 4-DoF movements of the endoscope while two other commercial hand interfaces map the movements of the two hands to the two instruments individually. An ex-vivo experiment was carried out by six subjects without surgical experience, where the simultaneous control with foot and hands was compared with a sequential clutch-based hand control. The participants could successfully teleoperate the endoscope and the two instruments to cut the tissues at scattered target areas in a porcine stomach. Foot control yielded 43.7% faster task completion and required less mental effort as compared to the clutch-based hand control scheme, which proves the concept of three-limb tele-operation surgery and the developed flexible endoscopic system.

easyEndo robotic endoscopy system: Development and usability test in a randomized controlled trial with novices and physicians

BACKGROUND

Some difficulties are common when using endoscopes. Steering is not intuitive, the endoscope weight is a physical burden to physicians and communication problems often occur between operators.

METHOD

To overcome these, we developed a robotic endoscopy system and conducted a usability test to compare conventional and robotic manipulation. Nine novices and eighteen physicians participated with the physicians being divided into intermediate and expert groups. The participants performed endoscope insertion into a simulator (physicians) or lesion marking on a testbed (novices) and simulate biopsies.

RESULT

Novices completed the tasks faster and with a lower workload when using robotic manipulation, whereas the experts showed the opposite trend. Still, the intermediates showed no significant difference as trials proceeded. Nevertheless, the learning curve analysis showed that the learning rate in all groups is greater for robotic manipulation (21.02% on average) than for conventional manipulation (13.75%) and predicted that physicians can reach manual performance.

CONCLUSION

The proposed robotic endoscopy system may allow solo-manipulation using one controller and may be more intuitive and convenient to use than conventional manipulation.

Robotics in flexible endoscopy: current status and future prospects

PURPOSE OF REVIEW

Advanced endoscopy procedures are technically challenging and require extensive training. Recent technological advances made in computer science and robotics have the potential to enhance the performance of complex intraluminal and transluminal interventions and potentially optimize precision and safety. This review covers the different technologies used for robot-assisted interventions in the gastrointestinal tract, organized according to their clinical availability, and focusing on flexible endoscopy-based systems.

RECENT FINDINGS

In the curvilinear gastrointestinal anatomy, robotic technology can enhance flexible endoscopes to augment effectiveness, safety, and therapeutic capabilities, particularly for complex intraluminal and transluminal interventions. Increased visual angles, increased degrees of freedom of instrumentation, optimized navigation, and locomotion, which may lead to a reduced physician learning curve and workload, are promising achievements with the promise to ultimately replace conventional endoscopy techniques for screening and therapeutic endoscopy.

SUMMARY

The majority of these devices are not commercially available yet. The best clinical applications are also currently being researched. Nonetheless, robotic assistance may encourage surgeons to use flexible endoscopes to administer surgical therapies and increase interest among gastroenterologists in advanced therapies. Robotics may be a means to overcome the technical obstacles of incisionless natural orifice procedures and favor an increased adoption of complex endoscopic procedures such as third-space therapies.

Successful Robotic Gastrectomy Does Not Require Extensive Laparoscopic Experience

Purpose

We evaluated the learning curve and short-term surgical outcomes of robot-assisted distal gastrectomy (RADG) performed by a single surgeon experienced in open, but not laparoscopic, gastrectomy. We aimed to verify the feasibility of performing RADG without extensive laparoscopic experience.

Materials and Methods

Between July 2012 and December 2016, 60 RADG procedures were performed by a single surgeon using the da Vinci^® Surgical System (Intuitive Surgical). Patient characteristics, the length of the learning curve, surgical parameters, and short-term postoperative outcomes were analyzed and compared before and after the learning curve had been overcome.

Results

The duration of surgery rapidly decreased from the first to the fourth case; after 25 procedures, the duration of surgery was stabilized, suggesting that the learning curve had been overcome. Cases were divided into 2 groups: 25 cases before the learning curve had been overcome (early cases) and 35 later cases. The mean duration of surgery was 420.8 minutes for the initial cases and 281.7 minutes for the later cases (P<0.001). The console time was significantly shorter during the later cases (168.6 minutes) than during the early cases (247.1 minutes) (P<0.001). Although the volume of blood loss during surgery declined over time, there was no significant difference between the early and later cases. No other postoperative outcomes differed between the 2 groups. Pathology reports revealed the presence of mucosal invasion in 58 patients and submucosal invasion in 2 patients.

Conclusions

RADG can be performed safely with acceptable surgical outcomes by experts in open gastrectomy.

Robotic Endoscopy

Endoscopes extend the eyes of the physician into the patient's body. They are widely used in gastrointestinal (GI) diagnostics and minimally invasive surgery. Endoscopes can be classified into 3 types: rigid, flexible, and capsule endoscopes. Rigid and flexible endoscopes are traditionally held and manipulated by the physician to visualize the region of interest, while capsule endoscopes move passively along with the GI peristalsis. With the advancement of technology, robotic endoscopy has been increasingly developed and accepted. In this work, robotic endoscopy from 3 categories (robot-assisted rigid endoscopy, robot-assisted flexible endoscopy, and active GI endoscopy including active flexible colonoscopy and active capsule endoscopy) is reviewed by PubMed search with the criteria ('Robotics' OR 'Robot') and ('Endoscopy' OR 'Endoscope').

Evaluation of the tip-bending response in clinically used endoscopes

BACKGROUND AND STUDY AIMS

Endoscopic interventions require accurate and precise control of the endoscope tip. The endoscope tip response depends on a cable pulling system, which is known to deliver a significantly nonlinear response that eventually reduces control. It is unknown whether the current technique of endoscope tip control is adequate for a future of high precision procedures, steerable accessories, and add-on robotics. The aim of this study was to determine the status of the tip response of endoscopes used in clinical practice.

MATERIALS AND METHODS

We evaluated 20 flexible colonoscopes and five gastroscopes, used in the endoscopy departments of a Dutch university hospital and two Dutch teaching hospitals, in a bench top setup. First, maximal tip bending was determined manually. Next, the endoscope navigation wheels were rotated individually in a motor setup. Tip angulation was recorded with a USB camera. Cable slackness was derived from the resulting hysteresis plot.

RESULTS

Only two of the 20 colonoscopes (10 %) and none of the five gastroscopes reached the maximal tip angulation specified by the manufacturer. Four colonoscopes (20 %) and none of the gastroscopes demonstrated the recommended cable tension. Eight colonoscopes (40 %) had undergone a maintenance check 1 month before the measurements were made. The tip responses of these eight colonoscopies did not differ significantly from the tip responses of the other colonoscopes.

CONCLUSION

This study suggests that the majority of clinically used endoscopes are not optimally tuned to reach maximal bending angles and demonstrate adequate tip responses. We suggest a brief check before procedures to predict difficulties with bending angles and tip responses.

Design and control of a novel gastroscope intervention mechanism with circumferentially pneumatic-driven clamping function

BACKGROUND

Robot-assisted manipulation is promising for solving problems such as understaffing and the risk of infection in gastro-intestinal endoscopy. However, the commonly used friction rollers in few existing systems have a potential risk of deforming flexible endoscopes for non-uniform clamping.

METHODS

This paper presents a robotic system for a standard flexible endoscope and focuses on a novel gastroscope intervention mechanism (GIM), which provides circumferentially uniform clamping with an airbag. The GIM works with a relay-on mechanism in a way similar to manual operation. The shear stiffness of airbag and the critical slipping force (CSF) were analysed to determine the parameters of the airbag. A fuzzy PID controller was employed to realize a fast response and high accuracy of pneumatic actuation. Experiments were performed to evaluate the accuracy, stiffness and CSF. In vitro and in vivo animal experiments were also carried out.

RESULTS

The GIM realized an accuracy of 0.025 ± 0.2 mm and -0.03 ± 0.25° for push-pull and rotation without delivery resistance. Under < 10 N delivery resistance, the error caused by the airbag stiffness was < 0.24 mm. A quadratic polynomial could be used to describe the relationship between the CSF and pneumatic pressure.

CONCLUSIONS

The novel GIM could effectively deliver gastroscopes. The pneumatic-driven clamping method proposed could protect the gastroscope by circumferentially uniform clamping force and the CSF could be properly controlled to guarantee operating safety. Copyright © 2016 John Wiley & Sons, Ltd.

A novel gastroscope intervention mechanism with circumferentially pneumatic-driven clamping function

Robotic assisted gastroscope delivery could solve various problems like understaffing, radiation and infection risk. The friction rollers commonly used in the few existed systems for traditional flexible endoscope, however, has potential risk of destroying scopes for non-uniform clamping. This research develops a novel gastroscope intervention mechanism (GIM) with a specially designed airbag. It evenly clamps the gastroscope with circumferential uniform pneumatic pressure. The GIM realizes axial and radial motion by means of the relay delivery mode similar to clinician's operation. The critical slipping force at different air pressure was analyzed to provide guidelines for safe intervention. Experiments were performed to evaluate the delivery accuracy and velocity and measure the critical slipping force. The results showed the axial and radial accuracy for delivery are 0.025±0.2mm and -0.03±0.25deg, respectively. The average velocity of 6.00mm·s(-1) and 75 deg·s(-1) were achieved to push/pull and twist the gastroscope. The relationship between the critical slipping force and air pressure could be fitted with a quadratic polynomial.

Feasibility of joystick guided colonoscopy

The flexible endoscope is increasingly used to perform minimal invasive interventions. A novel add-on platform allows single-person control of both endoscope and instrument at the site of intervention. The setup changes the current routine of handling the endoscope. This study aims to determine if the platform allows effective and efficient manipulation to position the endoscope at potential intervention sites throughout the bowel. Five experts in flexible endoscopy first performed three colonoscopies on a computer simulator using the conventional angulation wheels. Next they trained with the joystick interface to achieve their personal level of intubation time with low pain score. 14 PhD students (novices) without hands-on experience performed the same colonoscopy case using either the conventional angulation wheels or joystick interface. Both novice groups trained to gain the average expert level. The cecal intubation time, pain score and visualization performance (% of bowel wall) were recorded. All experts reached their personal intubation time in 6 ± 6 sessions. Three experts completed their learning curve with low pain score in 8 ± 6 sessions. The novices required 11 ± 6 sessions using conventional angulation wheels, and 12 ± 6 sessions using the joystick interface. There was no difference in the visualization performance between the novice and between the expert groups. This study shows that the add-on platform enables endoscope manipulation required to perform colonoscopy. Experts need only a relatively short training period. Novices are as effective and as efficient in endoscope manipulation when comparing the add-on platform with conventional endoscope control.