Assessment of a flexible robotic system for endoluminal applications and transanal total mesorectal excision (taTME): Could this be the solution we have been searching for?

Design of a Novel Haptic Joystick for the Teleoperation of Continuum-Mechanism-Based Medical Robots

Continuum robots are increasingly used in medical applications and the master–slave-based architectures are still the most important mode of operation in human–machine interaction. However, the existing master control devices are not fully suitable for either the mechanical mechanism or the control method. This study proposes a brand-new, four-degree-of-freedom haptic joystick whose main control stick could rotate around a fixed point. The rotational inertia is reduced by mounting all powertrain components on the base plane. Based on the design, kinematic and static models are proposed for position perception and force output analysis, while at the same time gravity compensation is also performed to calibrate the system. Using a continuum-mechanism-based trans-esophageal ultrasound robot as the test platform, a master–slave teleoperation scheme with position–velocity mapping and variable impedance control is proposed to integrate the speed regulation on the master side and the force perception on the slave side. The experimental results show that the main accuracy of the design is within 1.6°. The workspace of the control sticks is −60° to 110° in pitch angle, −40° to 40° in yaw angle, −180° to 180° in roll angle, and −90° to 90° in translation angle. The standard deviation of force output is within 8% of the full range, and the mean absolute error is 1.36°/s for speed control and 0.055 N for force feedback. Based on this evidence, it is believed that the proposed haptic joystick is a good addition to the existing work in the field with well-developed and effective features to enable the teleoperation of continuum robots for medical applications.

Clinical Robotic Surgery Association (India Chapter) and Indian rectal cancer expert group's practical consensus statements for surgical management of localized and locally advanced rectal cancer

INTRODUCTION

There are standard treatment guidelines for the surgical management of rectal cancer, that are advocated by recognized physician societies. But, owing to disparities in access and affordability of various treatment options, there remains an unmet need for personalizing these international guidelines to Indian settings.

METHODS

Clinical Robotic Surgery Association (CRSA) set up the Indian rectal cancer expert group, with a pre-defined selection criterion and comprised of the leading surgical oncologists and gastrointestinal surgeons managing rectal cancer in India. Following the constitution of the expert Group, members identified three areas of focus and 12 clinical questions. A thorough review of the literature was performed, and the evidence was graded as per the levels of evidence by Oxford Centre for Evidence-Based Medicine. The consensus was built using the modified Delphi methodology of consensus development. A consensus statement was accepted only if ≥75% of the experts were in agreement.

RESULTS

Using the results of the review of the literature and experts' opinions; the expert group members drafted and agreed on the final consensus statements, and these were classified as "strong or weak", based on the GRADE framework.

CONCLUSION

The expert group adapted international guidelines for the surgical management of localized and locally advanced rectal cancer to Indian settings. It will be vital to disseminate these to the wider surgical oncologists and gastrointestinal surgeons' community in India.

Envisioning the future of colorectal surgery: preclinical assessment and detailed description of an endoluminal robotic system (ColubrisMX ELS)

BACKGROUND

The EndoLuminal Surgical System (ELS) is an emerging non-linear robotic system specifically designed for transanal surgery that allows for excision of colorectal neoplasia and luminal defect closure.

METHODS

An evaluation of ELS was conducted by a single surgeon in a preclinical setting at the EndoSurgical Center of Florida in Orlando, between October 1st, 2020 and December 31st, 2020, using porcine colon as a model. Mock lesions measured 2.5 to 3.5 cm were excised partial-thickness. Specimen quality and excision time was assessed and evaluated.

RESULTS

Twenty consecutive robotic transanal minimally invasive surgery (TAMIS) operations utilizing the ELS system were successfully performed without fragmentation. The mean and standard deviation procedure time for all 20 cases was 18.41 ± 14.15 min. The latter 10 cases were completed in substantially less time, suggesting that ELS requires at least 10 preclinical cases for a surgeon to become familiar with the technology. A second task, namely suture closure of the partial-thickness defect, was performed in 9 of the 20 cases. Mean time and standard deviation for this task measured 27.89 ± 10.07 min. There were no adverse events.

CONCLUSIONS

ELS was successful in performing the tasks of partial-thickness disc excision and closure in a preclinical evaluation. Further study is necessary to determine its clinical applicability.

Robotic Transanal Total Mesorectal Excision (RTaTME): State of the Art

Total mesorectal excision (TME) is the gold standard technique for the surgical management of rectal cancer. The transanal approach to the mesorectum was introduced to overcome the technical difficulties related to the distal rectal dissection. Since its inception, interest in transanal mesorectal excision has grown exponentially and it appears that the benefits are maximal in patients with mid-low rectal cancer where anatomical and pathological features represent the greatest challenges. Current evidence demonstrates that this approach is safe and feasible, with oncological and functional outcome comparable to conventional approaches, but with specific complications related to the technique. Robotics might potentially simplify the technical steps of distal rectal dissection, with a shorter learning curve compared to the laparoscopic transanal approach, but with higher costs. The objective of this review is to critically analyze the available literature concerning robotic transanal TME in order to define its role in the management of rectal cancer and to depict future perspectives in this field of research.

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.

Feasibility of transanal total mesorectal excision (taTME) using the Medrobotics Flex® System

BACKGROUND

The use of transanal total mesorectal excision (taTME) for treatment of rectal cancer is growing, but anatomic constraints prevent access to the proximal rectum with rigid instruments. The articulated instrumentation of current surgical robots is promising in overcoming these limitations, but the bulky size of current platforms inhibits the proximal reach of dissection. Flexible robotic systems could overcome these constraints while maintaining a stable platform for dissection. The goal of this study was to evaluate feasibility of performing taTME using the semi-robotic Flex® System (Medrobotics Corp., Raynham, MA) in human cadavers.

METHODS

taTME was performed by two surgeons in six fresh human cadaveric specimens using the Flex® System, with or without transabdominal laparoscopic assistance. Both mid- and low-rectal lesions were simulated. Metrics including quality of visualization, maintenance of pneumorectum, maneuverability of instruments, effectiveness of pursestring suture placement, and dissection in an anatomically correct plane were evaluated.

RESULTS

The semi-robotic endoluminal platform allowed for excellent visualization, insufflation, and dissection during taTME. Adequate pursestring occlusion of the rectum was achieved in all six cases. In cadavers with simulated mid-rectal lesions (N = 4), dissection and anterior peritoneal entry was achieved in all cases, with abdominal assistance utilized in two of four cases. In cadavers with simulated low-rectal lesions (N = 2), dissection was incomplete and aborted due to difficulty maneuvering instruments in close proximity to the rigid transanal port.

CONCLUSIONS

Use of the Flex® system for taTME is feasible for mid-rectal dissection. Advantages over the traditional multi-armed robot include longer reach of instruments with the ability to dissect up to 17 cm from the anal verge, as well as tactile feedback. The current design of the flexible platform does not permit safe dissection in the distal rectum, although this constraint may be resolved with future adjustments to the equipment.

Assessment of the Versius surgical robotic system for dual-field synchronous transanal total mesorectal excision (taTME) in a preclinical model: will tomorrow's surgical robots promise newfound options?

BACKGROUND

The aim of this study was to evaluate the feasibility of the Versius surgical robotic system for transanal total mesorectal excision (taTME) in a preclinical setting.

METHODS

Dry laboratory and cadaveric sessions were first conducted for three experienced colorectal surgeons in order to gain familiarity with the modular surgical system and the robotic workstation. After introduction, the system was configured to allow for synchronous, totally robotic taTME in a cadaver.

RESULTS

Using the modular robotic system, one surgeon performed the abdominal portion of the operation, including colonic mobilization and vascular pedicle ligation while simultaneously a second surgeon performed the transanal portion of the operation to the point of rendezvous at the peritoneal reflection, where the operation was completed cooperatively. The operation was successfully completed in 195 min demonstrating preclinical feasibility of this unique approach with an emerging robotic system.

CONCLUSIONS

This is the first preclinical assessment of the Versius surgical robotic system for taTME. The ability to work simultaneously carries the theoretical advantage of reducing surgical time and thereby reducing overall operative costs. It may also allow surgeons to maintain focus on critical parts of the operation by halving the fatigue associated with long, complex cases such as taTME.

Transanal total mesorectal excision (TaTME): current status and future perspectives

Total mesorectal excision (TME) is the gold standard surgical treatment for mid- and low rectal cancer; however, it is associated with specific technical hurdles. Transanal TME (TaTME) is a new procedure developed to overcome these difficulties, through an enhanced visualization of the dissection plane. This potentially could result in a more accurate distal dissection with a lower rate of positive circumferential resection margins, increasing the rate of sphincter-saving procedures. The indications for TaTME are currently expanding, despite not being yet standardized, and structured training programs are ongoing to help overcome the steep learning curve related to the technique. The procedure is feasible and safe with similar intraoperative complications and readmission rates when compared with conventional open or laparoscopic TME. Favorable short-term oncologic results have been reported: in particular, TaTME is associated with mesorectal specimen of a better quality and a longer distal resection margin that is established at the beginning of the procedure under direct view. Robotics, when available, will probably overcome the steep learning curve related to the complexity of TaTME. Long-term follow-up and ongoing RCT trials data are awaited regarding functional results, local recurrence and survival, and to facilitate the comparison with standard laparoscopic or robotic rectal resections. The present review is focused on critically analyzing the theoretical benefits and risks of the procedure, its indications, short- and long-term results and future direction in the application of TaTME.

Transanal TME: new standard or fad?

Transanal total mesorectal excision (taTME) has been developed to overcome the difficulty of laparoscopic dissection and transection in the deep pelvis. TaTME has several clinical benefits over laparoscopic surgery, such as better exposure of the distal rectum and direct determination of distal resection margin. Although evidence demonstrating the true benefits of taTME over laparoscopic TME (LapTME) is still insufficient, accumulating data have revealed that, as compared with LapTME, taTME is associated with shorter operative time and a lower conversion rate without jeopardizing other short-term outcomes. However, taTME is a technically demanding procedure with specific complications such as urethral injury, and so sufficient experience of LapTME and step-by-step acquisition of the skills needed for this procedure are requisite. The role of transanal endoscopic surgery is expected to change, along with the recent progress in the treatment of rectal cancer, such as robotic surgery and the watch-and-wait strategy. Optimization of treatment will be needed in the future in terms not only of oncological but also of functional outcomes.

Robot-guided neuromapping during nerve-sparing taTME for low rectal cancer

PURPOSE

Intraoperative pelvic neuromapping with electrophysiological evaluation of autonomic nerve preservation during robotic total mesorectal excision (TME) for rectal cancer is conventionally performed by the bedside assistant with a hand-guided probe. Our goal was to return autonomy over the neuromonitoring process to the colorectal surgeon operating the robotic console.

METHODS

A recently described prototype microfork electrostimulation probe was evaluated intraoperatively during abdominal robotic-assisted transanal TME (taTME) surgery for low rectal cancer in three consecutive male patients.

RESULTS

An intraoperative video demonstrates the good control and maneuverability of the prototype probe with electrophysiological confirmation of bilateral pelvic autonomic nerve preservation.

CONCLUSIONS

This study presents the first in situ application of a new microfork probe for fully robot-guided neuromapping in three patients undergoing TME surgery for low rectal cancer.

Robotics for Advanced Therapeutic Colonoscopy

Although colonoscopy was originally a diagnostic imaging procedure, it has now expanded to include an increasing range of therapeutic interventions. These procedures require precise maneuvers of instruments, execution of force, efficient transmission of force from the operator to the point of application, and sufficient dexterity in the mobilization of endoscopic surgical instruments. The conventional endoscope is not designed to support technically demanding endoscopic procedures. In case of colonoscopy, the tortuous anatomy of the colon makes inserting, moving, and orientating the endoscope difficult. Exerting excessive pressure can cause looping of the endoscope, pain to the patient, and even perforation of the colon. To mitigate the technical constraints, numerous technically enhanced systems have been developed to enable better control of instruments and precise delivery of force in the execution of surgical tasks such as apposing, grasping, traction, counter-traction, and cutting of tissues. Among the recent developments are highly dexterous robotic master and slave systems, computer-assisted or robotically enhanced conventional endoscopes, and autonomously driven locomotion devices that can effortlessly traverse the colon. Developments in endoscopic instrumentations have overcome technical barriers and opened new horizons for further advancements in therapeutic interventions. This review describes examples of some of these systems in the context of their applications to advanced therapeutic colonoscopy.

Review and update: robotic transanal surgery (RTAS)

As the field of surgery advances, new approaches have allowed surgeons additional flexibility to perform further interventions with minimal or no external incisions. For many years, single site access (SSA) has been used for transanal procedures, and platforms allowing modified endoscopic approaches have been available. These platforms have limitations related to access, visualization, dexterity, camera control, and instrumentation. Recently, surgical robotics companies have developed and introduced new technologies and platforms, which may help address some of these limitations. Comprehensive internet, open access, and medical and industry conference reviews of robotic surgery platforms and technology available for use in SSA surgery were conducted and 30 articles were found using keywords "robotic surgery, transanal, single site, robotic transanal surgery". A PubMed, Medline, Journals @OVID and open access search for data related to these platforms and technologies was also performed yielding 11 articles. Abstracts were reviewed for those written in the English language, leaving 40 articles which were then filtered for those pertaining to robotic surgery, transanal. 58 abstracts were found, duplicates were eliminated, and the remaining 35 articles were read in their entirety by two reviewers. Several new and existing platforms are identified for use in SSA surgery for transanal surgery as well as abdominal and transoral surgery. These are reviewed, including brand, features, approved and suggested uses, and potential limitations. New robotic technologies serve to enhance the ability of surgeons to perform SSA surgery. This next generation of robotic surgery technology overcomes some of the limitations of preceding endoscopic SSA surgery technology and will enhance the advancement of robotic transanal surgery, but outcomes and performance data are still limited.

Direct target NOTES: prospective applications for next generation robotic platforms

BACKGROUND

A new era in surgical robotics has centered on alternative access to anatomic targets and next generation designs include flexible, single-port systems which follow circuitous rather than straight pathways. Such systems maintain a small footprint and could be utilized for specialized operations based on direct organ target natural orifice transluminal endoscopic surgery (NOTES), of which transanal total mesorectal excision (taTME) is an important derivative.

METHODS

During two sessions, four direct target NOTES operations were conducted on a cadaveric model using a flexible robotic system to demonstrate proof-of-concept of the application of a next generation robotic system to specific types of NOTES operations, all of which required removal of a direct target organ through natural orifice access. These four operations were (a) robotic taTME, (b) robotic transvaginal hysterectomy in conjunction with (c) robotic transvaginal salpingo-oophorectomy, and in an ex vivo model, (d) trans-cecal appendectomy.

RESULTS

Feasibility was demonstrated in all cases using the Flex^® Robotic System with Colorectal Drive. During taTME, the platform excursion was 17 cm along a non-linear path; operative time was 57 min for the transanal portion of the dissection. Robotic transvaginal hysterectomy was successfully completed in 78 min with transvaginal extraction of the uterus, although laparoscopic assistance was required. Robotic transvaginal unilateral salpingo-oophorectomy with transvaginal extraction of the ovary and fallopian tube was performed without laparoscopic assistance in 13.5 min. In an ex vivo model, a robotic trans-cecal appendectomy was also successfully performed for the purpose of demonstrating proof-of-concept only; this was completed in 24 min.

CONCLUSIONS

A flexible robotic system has the potential to access anatomy along circuitous paths, making it a suitable platform for direct target NOTES. The conceptual operations posed could be considered suitable for next generation robotics once the technology is optimized, and after further preclinical validation.

Lower Gastrointestinal Surgery: Robotic Surgery versus Laparoscopic Procedures

Introduction

For a long time, the comprehensive application of minimally invasive techniques in lower gastrointestinal (GI) surgery was substantially impaired by inherent anatomical and technical complexities. Recently, several new techniques such as robotic operating platforms and transanal total mesorectal excision (taTME) have revolutionized the minimally invasive approach. This review aims to depict the current state of the art and evaluates the advantages and drawbacks in regard to perioperative outcome and quality of oncological resection.

Methods

A systematic literature search was performed using the search terms 'colorectal cancer', 'rectal cancer', 'minimally invasive surgery', 'laparoscopic surgery', and 'robotic' to identify relevant studies reporting on robotic surgery (RS) either alone or in comparison to laparoscopic surgery (LS). Publications on taTME were analyzed separately.

Results

69 studies reporting on RS with a total of 20,872 patients, and 17 articles on taTME including 881 patients, were identified.

Conclusion

Both RS and taTME can facilitate a minimally invasive approach for lower GI surgery in an increasing number of patients. Furthermore, combining both techniques might become an auspicious approach in selected patients; further prospective and randomized trials are needed to verify its benefits over conventional laTME.