Evaluation of a new multitasking platform for endoscopic full-thickness resection

Robotics in interventional endoscopy-evolution and the way forward

The integration of robotics into gastrointestinal (GI) endoscopy represents a transformative advancement and bears the potential to bridge the gap between traditional limitations by offering unprecedented precision and control in diagnostic and therapeutic procedures. This review explores the historical progression, current applications and future potential of robotic platforms in GI endoscopy. Originally designed for surgical applications, robotic systems have expanded their reach into endoscopy, potentially enhancing procedural accuracy and reducing ergonomic strain on practitioners. Natural Orifice Transluminal Endoscopic Surgery (NOTES) emerged as a promising technique, leveraging natural orifices to perform minimally invasive surgeries. Despite its initial potential, several factors, including limitations of the available instrumentations and lack of reliable closure techniques, hindered its widespread adoption and progress. Conventional endoscopic tools often fall short in terms of triangulation, traction and degrees of freedom, necessitating the adoption of robotic interventions. Over recent decades, robotic endoscopy has significantly evolved, focusing on both diagnostic and complex therapeutic procedures such as endoscopic sub-mucosal dissection (ESD) and endoscopic full-thickness resection (EFTR). Various robotic platforms demonstrate enhanced safety and efficiency in GI procedures. As the field progresses, the emphasis on clinical validation, advanced training and the exploration of new applications remains crucial. Continuous innovation in robotic technology and endoscopic techniques promises to overcome existing limitations, further revolutionizing the management of GI diseases and improving patient outcomes.

Flexible robotic endoscopy for treating gastrointestinal neoplasms

Therapeutic flexible endoscopic robotic systems have been developed primarily as a platform for endoscopic submucosal dissection (ESD) in the treatment of early-stage gastrointestinal cancer. Since ESD can only be performed by highly skilled endoscopists, the goal is to lower the technical hurdles to ESD by introducing a robot. In some cases, such robots have already been used clinically, but they are still in the research and development stage. This paper outlined the current status of development, including a system by the author’s group, and discussed future challenges.

A Look into the Future of Endoscopic Submucosal Dissection and Third Space Endoscopy: The Role for Robotics and Other Innovation

Endoscopic resection has been widely applied especially in endoscopic submucosal dissection and third space endoscopy (TSE). Flexible endoluminal robotics allow performance of endoscopic submucosal dissection with exposure of the submucosal plane for precise dissection using two robotic arms. The introduction of TSE revolutionized the horizon of therapeutic endoscopy to the submucosal space beneath and beyond the mucosa. Advantages of TSE include avoidance of full thickness incision in gastrointestinal tract through the submucosal tunneling for performance of peroral endoscopic myotomy and submucosal tunneling endoscopic resection. In future, robotic-driven devices should be developed to enhance performance of complex endoluminal procedures and TSE.

Progress in Control-Actuation Robotic System for Gastrointestinal NOTES Development

Purpose

Natural orifice transluminal endoscopic surgery (NOTES) is a minimally invasive surgical procedure that reduces patient trauma, infection probability, and rehabilitation time. This paper reviews the progress made in the control-actuation robotic systems for gastrointestinal NOTES development. Material and Methods. A survey on both existing and state-of-the-art control-actuation robotic systems for gastrointestinal NOTES was conducted in December 2021.

Results

Nine control-actuation robotic systems for gastrointestinal NOTES were identified. The structures and specifications of these robotic systems were reported. The technical parameters were also discussed. Special attention was directed to systems using a control-actuation structure and tendon-driven mechanism. The control-actuation robotic systems typically deploy a control-actuation structure and tendon-driven mechanism. Control-actuation robotic systems for gastrointestinal NOTES show great ability to improve operational accuracy and flexibility and flatten the learning curve of procedures. These characteristics suggest that the use of control-actuation robotic systems is worth exploring in future development.

Robotics in therapeutic endoscopy (with video)

Since its inception, endoscopy has evolved from a solely diagnostic procedure to an expanding therapeutic field within gastroenterology. The incorporation of robotics in gastroenterology initially addressed shortcomings of flexible endoscopes in natural orifice transluminal endoscopy. Developing therapeutic endoscopic robotic platforms now offer operators improved ergonomics, visualization, dexterity, precision, and control and the possibility of increasing proficiency and standardization of complex endoscopic procedures including endoscopic submucosal dissection, endoscopic full-thickness resection, and endoscopic suturing. The following review discusses the history, potential applications, and tools currently available and in development for robotics in therapeutic endoscopy.

Surgical Robot for Intraluminal Access: An Ex Vivo Feasibility Study

Early-stage gastrointestinal cancer is often treated by endoscopic submucosal dissection (ESD) using a flexible endoscope. Compared with conventional percutaneous surgery, ESD is much less invasive and provides a high quality of life for the patient because it does not require a skin incision, and the organ is preserved. However, the operator must be highly skilled because ESD requires using a flexible endoscope with energy devices, which have limited degrees of freedom. To facilitate easier manipulation of these flexible devices, we developed a surgical robot comprising a flexible endoscope and two articulating instruments. The robotic system is based on a conventional flexible endoscope, and an extrapolated motor unit moves the endoscope in all its degrees of freedom. The instruments are thin enough to allow insertion of two instruments into the endoscope channel, and each instrument has a bending section that allows for up–down, right–left, and forward–backward motion. In this study, we performed an ex vivo feasibility evaluation using the proposed robotic system for ESD in a porcine stomach. The procedure was successfully performed by five novice operators without complications. Our findings demonstrated the feasibility of the proposed robotic system and, furthermore, suggest that even operators with limited experience can use this system to perform ESD.

Robotic endoscopy. A review of the literature

Purpose

To present new endoscopic robotic devices in the context of minimally invasive procedures with high precision and automation.

Methods

Review of the literature by December 2018 on robotic endoscopy.

Results

We present the studies and investments for robotic implementation and flexible endoscopy evolution. We divided them into forceps manipulation platforms, active endoscopy and endoscopic capsule. They try to improve forceps handling and stability and to promote active movement.

Conclusion

The implementation and propagation of robotic models depend on doing what the endoscopist is unable to. The new devices are moving forward in this direction.

A Pilot Study of Endoscopic Submucosal Dissection Using an Endoscopic Assistive Robot in a Porcine Stomach Model

Background/Aims

Endoscopic assistive devices have been developed to reduce the complexity and improve the safety of surgeries involving the use of endoscopes. We developed an assistive robotic arm for endoscopic submucosal dissection (ESD) and evaluated its efficiency and safety in this in vitro pilot study.

Methods

ESD was performed using an auxiliary transluminal endoscopic robot. An in vitro test bed replicating the intra-abdominal environment and pig stomachs were used for the experiment. Participants were divided into skilled operators and unskilled operators. Each group performed ESD 10 times by using both conventional and robot-assisted methods. The perforation incidence, operation time, and resected mucous membrane size were measured.

Results

For the conventional method, significant differences were noted between skilled and unskilled operators regarding operation time (11.3 minutes vs 26.7 minutes) and perforation incidence (0/10 vs 6/10). Unskilled operators showed a large decrease in the perforation incidence with the robot-assisted method (conventional method vs robot-assisted method, 6/10 vs 1/10). However, the operation time did not differ between the conventional and robot-assisted methods. On the other hand, skilled operators did not show differences in the operation time and perforation incidence between the conventional and robot-assisted methods. Among both skilled and unskilled operators, the operation time decreased with the robot-assisted method as the experiment proceeded.

Conclusions

The surgical safety of unskilled operators greatly improved with robotic assistance. Thus, our assistive robotic arm was beneficial for ESD. Our findings suggest that endoscopic assistive robots have positive effects on surgical safety.

Development of a Novel Gastrointestinal Endoscopic Robot Enabling Complete Remote Control of All Operations: Endoscopic Therapeutic Robot System (ETRS)

Background and Objective

The master and slave transluminal endoscopic robot and other flexible endoscopy platforms are designed primarily for the remote control of forceps, with manipulation of the endoscope itself still dependent on conventional techniques. We have developed an endoscopic therapeutic robot system (ETRS) that provides complete remote control of all forceps and endoscope operations.

Method

We carried out endoscopic submucosal dissection (ESD) in porcine stomachs using the ETRS. All procedures were completed with the endoscopist seated at the console the entire time.

Results

Total en bloc resection was achieved in all 7 cases with no complications. The mean total procedure time was 36.14 ± 14.98 min, the mean size of the resected specimen was 3.39 ± 0.66 cm × 3.03 ± 0.63 cm, and the mean dissection time was 14.91 ± 8.61 min.

Conclusion

We successfully used the ETRS to perform completely remote-controlled ESD in porcine stomachs.

Endoscopic full-thickness resection for gastric gastrointestinal stromal tumor originating from the muscularis propria

SUMMARY OBJECTIVE: This study retrospectively reviewed 46 cases of gastric gastrointestinal stromal tumors treated by endoluminal endoscopic full-thickness resection (EFR) microsurgery in our gastrointestinal endoscopy center. We aimed to evaluate the EFR for the treatment of gastric gastrointestinal stromal tumors originating from the muscularis propria. METHODS: A total of 46 patients with gastric gastrointestinal stromal tumors originated from the muscularis propria layer from January 2012 to June 2015 were treated with EFR. The patients were followed up with gastroscope and computed tomography (CT) for evaluation of therapeutic effect and safety. RESULTS: EFR was successfully accomplished to remove all tumors in 46 patients. The mean procedure time was 82.5±39.8min (56-188min). Except in 3 leiomyomas, pathological examination confirmed gastrointestinal stromal tumor (GIST) in 43 cases. None of the patients had occurred bleeding, peritonitis and other complications after EFR. Thereafter, all patients were followed up with gastro-scope after 1, 6,12 months. CONCLUSIONS: EFR is effective and safe for patients with gastric gastrointestinal stromal tumors originated from muscularis propria layer and has the advantage of less invasive treatment and higher tumor resection rate. It should be considered for further application.

Haptic feedback is useful in remote manipulation of flexible endoscopes

Background and study aims  We developed the Endoscopic Operation Robot (EOR) version 3, offering built-in haptic feedback and manipulation of the entire scope with one hand. Manipulation of the flexible endoscope is done entirely remotely. However, inclusion of haptic feedback places a huge burden on the system. Our purpose in this study was to determine whether haptic feedback is needed in remote manipulation of a flexible endoscope. Methods  Five endoscopists performed total colonoscopy using a colonoscopy training model. A trial was conducted in which the endoscope was inserted up to the cecum five times with haptic feedback and five times without haptic feedback. Insertion time, maximum and mean haptic force, and incidence of sigmoid colon overstretching were compared between groups. Results  Insertion time was significantly shorter with haptic feedback than without, and overstretching of the sigmoid colon was less frequent. Insertion could thus be performed without using excessive force. Conclusion  Haptic feedback is useful for remote control manipulation of flexible endoscopes.

A new robotic-assisted flexible endoscope with single-hand control: endoscopic submucosal dissection in the ex vivo porcine stomach

BACKGROUND

Difficulties in endoscopic operations and therapeutic procedures seem to occur due to the complexity of operating the endoscope dial as well as difficulty in performing synchronized movements with both hands. We developed a prototype robotic-assisted flexible endoscope that can be controlled with a single hand in order to simplify the operation of the endoscope. The aim of this study was to confirm the operability of the robotic-assisted flexible endoscope (RAFE) by performing endoscopic submucosal dissection (ESD).

METHODS

Study 1: ESD was performed manually or with RAFE by an expert endoscopist in ex vivo porcine stomachs; six operations manually and six were performed with RAFE. The procedure time per unit circumferential length/area was calculated, and the results were statistically analyzed. Study 2: We evaluated how smoothly a non-endoscopist can move a RAFE compared to a manual endoscope by assessing the designated movement of the endoscope.

RESULTS

Study 1: En bloc resection was achieved by ESD using the RAFE. The procedure time was gradually shortened with increasing experience, and the procedure time of ESD performed with the RAFE was not significantly different from that of ESD performed with a manual endoscope. Study 2: The time for the designated movement of the endoscope was significantly shorter with a RAFE than that with a manual endoscope as for a non-endoscopist.

CONCLUSIONS

The RAFE that we developed enabled an expert endoscopist to perform the ESD procedure without any problems and allowed a non-endoscopist to control the endoscope more easily and quickly than a manual endoscope. The RAFE is expected to undergo further development.

Flexible robotic endoscopy: current and original devices

Two current major research topics concern the incorporation of flexible robotic endoscopy systems developed for natural-orifice translumenal endoscopic surgery (NOTES), primarily for the purpose of remote forceps operation, into endoscopic submucosal dissection (ESD) and other flexible endoscopic treatments and the use of robots for the manipulation of flexible endoscopes themselves with the aim of enabling the remote insertion of colonoscopes, etc. However, there are still many challenges that remain to be addressed; the ideal robotic endoscope has not yet been realized. This article reviews the ongoing developments and our own efforts in the area of flexible robotic endoscopy.

Current and emerging robotic assisted intervention for Notes

INTRODUCTION

Natural orifices transluminal endoscopic surgery (notes) procedures are limited by a number of factors including closure of the internal entry point, loss of triangulation, and unstable operative platform. Areas covered: In this paper, new technical developments in different aspects of robotic assisted NOTES interventions are reviewed. We further address new research opportunities for more widespread clinical acceptance of robotic assisted NOTES procedures. Expert commentary: The application of robotics in NOTES intervention is still in its infancy. The development of more compact, smart and intuitive robotic NOTES systems holds much promise for the future of NOTES application.

Review of Pure Endoscopic Full-Thickness Resection of the Upper Gastrointestinal Tract

Natural-orifice transluminal endoscopic surgery (NOTES) using flexible endoscopy has attracted attention as a minimally invasive surgical method that does not cause an operative wound on the body surface. However, minimizing the number of devices involved in endoscopic, compared to laparoscopic, surgeries has remained a challenge, causing endoscopic surgeries to gradually be phased out of use. If a flexible endoscopic full-thickness suturing device and a counter-traction device were developed to expand the surgical field for gastrointestinal-tract collapse, then endoscopic full-thickness resection using NOTES, which is seen as an extension of endoscopic submucosal dissection for full-thickness excision of tumors involving the gastrointestinal-tract wall, might become an extremely minimally invasive surgical method that could be used to resect only full-thickness lesions approached by the shortest distance via the mouth. It is expected that gastroenterological endoscopists will use this surgery if device development is advanced. This extremely minimally invasive surgery would have an immeasurable impact with regard to mitigating the burden on patients and reducing healthcare costs. Development of a new surgical method using a multipurpose flexible endoscope is therefore considered a socially urgent issue.

Endoscopic surgery - exploring the modalities

The adoption of endoscopic surgery continues to expand in clinical situations with the recent natural orifice transluminal endoscopic surgery technique enabling abdominal organ resection to be performed without necessitating any skin incision. In recent years, the development of numerous devices and platforms have allowed for such procedures to be carried out in a safer and more efficient manner, and in some ways to better simulate triangulation and surgical tasks (e.g., suturing and dissection). Furthermore, new novel techniques such as submucosal tunneling, endoscopic full-thickness resection and hybrid endo-laparoscopic approaches have further widened its use in more advanced diseases. Nevertheless, many of these new innovations are still at their pre-clinical stage. This review focuses on the various innovations in endoscopic surgery, with emphasis on devices and techniques that are currently in human use.

Effect of nanostructured thin film on minimally invasive surgery devices applications: characterization, cell cytotoxicity evaluation and an animal study in rat

BACKGROUND

Minimally invasive surgery is performed using an endoscope and other instruments including the electrosurgical units. However, concerns including surgical smoke, tissue sticking and thermal injury are remaining in electrosurgery.

AIMS

Accordingly, a newly developed electrosurgical electrode coating with hydrogenated Cu-incorporated diamond-like carbon (DLC-Cu) film is purposed to improve the instrument performance.

METHODS

The morphologies of DLC-Cu surfaces were characterized using transmission electron microscopy, scanning electron microscopy and atomic force microscopy. In this study, lesions were made on the liver lobes of adult rats, using a monopolar electrosurgical unit equipped with untreated stainless steel electrodes or treated-electrodes. Animals were killed for evaluations at 0, 3, 7 and 28 days postoperatively.

RESULTS

Treated-electrodes generate less sticking tissues and adhesive blood cells. Thermography revealed that the surgical temperature in liver tissue from the treated-electrode was significantly lower than the untreated-electrode. Total injury area of livers treated with treated-electrodes was significantly smaller than the untreated-electrodes treatment. Moreover, treated-electrodes caused a relatively smaller area of lateral thermal injury, a smaller area of fibrotic tissue and a faster process of remodeling than the untreated-electrodes. Western blot analysis showed that rats treated with treated-electrode expressed lower levels of NF-κB, caspase-3 and MMP-9 than untreated-electrode. Immunofluorescence staining for caspase-3 revealed that the untreated-electrode caused more serious injury.

CONCLUSIONS

This study reveals that the plating of electrodes with hydrogenated Cu-incorporated diamond-like carbon film is an efficient method for improving the performance of electrosurgical units, and should benefit wound remodeling. However, more tests must be carried out to confirm these promising findings in human patients.

Flexible endoscopic robot

Natural orifice transluminal endoscopic surgery (NOTES) is a novel surgical procedure during which abdominal operations can be performed with an endoscope passed through a natural orifice through an internal incision in the stomach, vagina, bladder or colon. NOTES is still evolving and many barriers stand on its way before it can gain acceptance in modern surgical practice. Effective access to the peritoneal cavity, closure techniques of the natural orifice access sites, development of a multitasking platform to accomplish procedures and support for special orientation are only a handful of its known limitations. Although the endoscope and conventional tools are useful for simple procedures, many important and complicated procedures are currently not possible due to limitation of degree of freedom (DOF) of the end effectors. We have developed a Master and Slave Transluminal Endoscopic Robot (MASTER) with nine degrees of freedom (DOF) in end effectors, which are long and flexible so as to enhance endoscopic procedures and NOTES. Using MASTER we have successfully performed endoscopic sub-mucosal dissections (ESD) to segmental hepatectomies in animal models. Thus, the MASTER robotic system shows great potential to perform new surgical procedures that are otherwise not possible with conventional endoscopic tools.

[Ongoing Development and Directions in Flexible Robotic Endoscopy]

The robotic system for flexible endoscopy was first developed as a platform enabling tissue triangulation in natural-orifice translumenal endoscopic surgery (NOTES). Then endoscopic submucosal dissection (ESD) was introduced and has widely been employed for the treatment of early gastrointestinal carcinoma. Subsequently, endoscopists became well aware of the limitations of their endoscopic manipulations with the conventional flexible endoscopes developed for diagnostic use, which led to the development of robotic systems for upper/lower gastrointestinal tract endoscopes intended for therapeutic use. Most flexible robotic endoscopes have 2 mechanical arms attached to the head, allowing surgeons to perform endoscopic manipulations, such as grasping, traction, incision, excision, and hemostasis. However, there are still many challenges that remain to be addressed: the ideal robotic endoscope has not yet been realized. This article reviews the ongoing developments and our own efforts in the area of flexible robotic endoscopy.

Application of clips assisted with foreign body forceps in defect closure after endoscopic full-thickness resection

BACKGROUND

This study was designed to evaluate the feasibility and efficacy of metallic clips assisted with foreign body forceps closing the gastric wall defect after endoscopic full-thickness resection (EFR) for gastric submucosal tumors (SMTs).

METHODS

Eighteen patients with gastric SMTs originated from the muscularis propria were treated by EFR between September 2012 and June 2014. Twelve patients underwent endoscopic closure of the gastric wall defects after EFR with endoloop and metallic clips (endoloop string suture method, ESSM), and six patients with clips and foreign body forceps (clips assisted with foreign body forceps clip method, CFCM).

RESULTS

No significant differences existed between the two groups in terms of demographics, clinical characteristics, and the size of the gastric wall defects. The average time spent in closing the gastric wall defects (14.83 ± 1.94 min for the CFCM group and 22.42 ± 5.73 min for the ESSM group) and hospitalization fees of the CFCM group were significantly lower than those of the ESSM group. The average hospitalization time of the two groups had no statistical significance. No single case had surgical intervention or complications, such as gastric bleeding, perforation, peritonitis, or abdominal abscess.

CONCLUSION

The CFCM and the ESSM are safe and effective techniques for gastric defect closure after EFR for gastric SMTs. Because of the "chopsticks effect," the CFCM more suitable for the lesions located at the gastric fundus, the greater curvature or anterior wall of the gastric body and gastric antrum.

Closure of iatrogenic large mucosal and full-thickness defects of the stomach with endoscopic interrupted sutures in in vivo porcine models: are they durable enough?

BACKGROUND

In this study, we evaluated the technical feasibility of mucosal approximation of large ulcers via an endoscopic suturing system after endoscopic submucosal dissection (ESD), assessed the durability of these sutures, and compared this technique with serosal apposition of full-thickness gastric wall defects using the same device.

METHODS

Post-ESD ulcers were closed with mucosal apposition in 7 pigs, and endoscopic full-thickness resection (EFTR) defects were closed with serosal apposition in 3 pigs. Pigs recovered for 1 week; they were then euthanized and necropsies were performed.

RESULTS

Primary defect closure was achieved in 85.7% of the post-ESD closures and in 100% of the post-EFTR closures (p = 0.67). All pigs survived for 1 week. At necropsy, sutures had loosened in the post-ESD animals, although only minor deformity of the ulcer edges was observed in all repaired post-ESD ulcers. Meanwhile, all of the post-EFTR defect closures were sustained for 1 week.

CONCLUSIONS

Primary closure of post-therapeutic defects can be accomplished using the device. Inverted serosal apposition provides a more durable and reliable repair than everted mucosal apposition.

A state of the art review and categorization of multi-branched instruments for NOTES and SILS

BACKGROUND

Since the advent of Natural Orifice Translumenal Endoscopic Surgery (NOTES) and single incision laparoscopic surgery (SILS), a variety of multitasking platforms have been under development with the objective to allow for bimanual surgical tasks to be performed. These instruments show large differences in construction, enabled degrees of freedom (DOF), and control aspects.

METHODS

Through a literature review, the absence of an in-depth analysis and structural comparison of these instruments in the literature is addressed. All the designed and prototyped multitasking platforms are identified and categorized with respect to their actively controlled DOF in their shafts and branches. Additionally, a graphical overview of patents, bench test experiments, and animal and/or human trials performed with each instrument is provided.

RESULTS

The large range of instruments, various actuation strategies, and different direct and indirect control methods implemented in the instruments show that an optimal instrument configuration has not been found yet. Moreover, several questions remain unanswered with respect to which DOF are essential for bimanual tasks and which control methods are best suited for the control of these DOF.

CONCLUSIONS

Considering the complexity of the currently prototyped and tested instruments, future NOTES and SILS instrument development will potentially necessitate a reduction of the available DOF to minimize the control complexity, thereby allowing for single surgeon bimanual task execution.

Minimally invasive surgical instruments with an accessory channel capable of integrating fibre-optic cable for optical biopsy: A review of the state of the art

This review article provides a comprehensive overview and classification of minimally invasive surgical instruments with an accessory channel incorporating fibreoptics or another auxiliary device for various purposes. More specifically, this review was performed with the focus on the newly emerging field of optical biopsy, its objective being to discuss primarily the instruments capable of carrying out the optical biopsy and subsequent tissue resection. Instruments housing the fibreoptics for other uses, as well as instruments with an accessory channel capable of housing the fibreoptics instead of their original auxiliary device after relevant design modifications, supplement the review. The entire Espacenet and Scopus databases were searched, yielding numerous patents and articles on conceptual and existing instruments satisfying the criteria. The instruments were categorised based on the function the fibreoptics or the auxiliary device serves. On the basis of their geometrical placement with respect to the tissue resector or manipulator, the subcategories were further defined. This subdivision was used to identify the feasibility of performing the optical biopsy and the tissue resection in an accurate and successive fashion. In general, the existing concepts or instruments are regarded as limited with regard to such a functionality, either due to the placement of their accessory channel with or without the fibreoptics or due to the operational restrictions of their tissue manipulators. A novel opto-mechanical biopsy harvester, currently under development at Delft University of Technology, is suggested as a promising alternative, ensuring a fast and accurate succession of the optical and the mechanical biopsies of a flat superficial tissue.

Endoscopic full-thickness resection and laparoscopic surgery for treatment of gastric stromal tumors

AIM: To assess the effectiveness of endoscopic full-thickness resection (EFR) and laparoscopic surgery in the treatment of gastric stromal tumors arising from the muscularis propria.

METHODS: Out of 62 gastric stromal tumors arising from the muscularis propria, each > 1.5 cm in diameter, 32 were removed by EFR, and 30 were removed by laparoscopic surgery. The tumor expression of CD34, CD117, Dog-1, S-100, and SMA was assessed immunohistochemically. The operative time, complete resection rate, length of hospital stay, incidence of complications, and recurrence rate were compared between the two groups. Continuous data were compared using independent samples t-tests, and categorical data were compared using χ² tests.

RESULTS: The 32 gastric stromal tumors treated by EFR and the 30 treated by laparoscopic surgery showed similar operative time [20-155 min (mean, 78.5 ± 30.1 min) vs 50-120 min (mean, 80.9 ± 46.7 min), P > 0.05], complete resection rate (100% vs 93.3%, P > 0.05), and length of hospital stay [4-10 d (mean, 5.9 ± 1.4 d) vs 4-19 d (mean, 8.9 ± 3.2 d), P >0.05]. None of the patients treated by EFR experienced complications, whereas two patients treated by laparoscopy required a conversion to laparotomy, and one patient had postoperative gastroparesis. No recurrences were observed in either group. Immunohistochemical staining showed that of the 62 gastric stromal tumors diagnosed by gastroscopy and endoscopic ultrasound, six were leiomyomas (SMA-positive), one was a schwannoglioma (S-100 positive), and the remaining 55 were stromal tumors.

CONCLUSION: Some gastric stromal tumors arising from the muscularis propria can be completely removed by EFR. EFR could likely replace surgical or laparoscopic procedures for the removal of gastric stromal tumors.

Natural orifice transluminal endoscopic surgery (NOTES) for clinical management of intra-abdominal diseases

Clinical research on natural orifice transluminal endoscopic surgery (NOTES) has been increasingly reported over the past 5 years and more than 1200 patients have received various NOTES procedures. The present article reviews the clinical practice of NOTES for the treatment of intra-abdominal diseases, and was carried out through systematic search with specific keywords in major databases for NOTES-related clinical literature. The last date of the search was 15 August, 2012. Transvaginal cholecystectomy is the commonest NOTES procedure reported, and its clinical feasibility and safety was established through prospective case series and randomized trials. There is a regional difference in NOTES development with the majority of NOTES fromCaucasian countries being transvaginal cholecystectomy and most reports from Asian countries being NOTES-related procedures. Safe closure of gastrointestinal access remains challenging, and novel endoscopic instruments are essential to enhance future development of NOTES.

Feasibility of full-thickness gastric resection using master and slave transluminal endoscopic robot and closure by Overstitch: a preclinical study

BACKGROUND

Gastric submucosal tumors are often treated by laparoscopic wedge resection. This study aimed to examine the feasibility of gastric full-thickness resection through a totally endoscopic approach using the master and slave transluminal endoscopic robot (MASTER), and closure of the luminal defect with an endoscopic suturing device.

METHODS

The operation was performed in two live porcine models under general anesthesia. First, the anterior wall of the stomach was slung to the abdominal wall using a percutaneous suturing device. An imaginary 5-cm lesion was marked using a needle knife. After the initial mucosal incision was made using an IT knife, the MASTER was introduced through a long overtube. A circumferential mucosal incision was completed with the MASTER to expose the muscularis propria which was grasped and incised to the serosal layer by electrocautery applied through the hook of the MASTER. The full-thickness resection of the gastric wall was completed with retraction using the grasper and dissection using the hook. While the defect was being created, the luminal space was maintained with traction of the percutaneous sutures. The defect was closed with suture plication using an Apollo Overstitch device.

RESULTS

Two full-thickness gastric resections were performed in two nonsurvival porcine models (body weight = 30 and 35 kg, respectively) using the MASTER. The total procedure time was 56 min for the first model and 70 min for the second model. The luminal view was maintained during the whole procedure, and there was no damage to surrounding organs throughout the whole procedure. The gastric defects were closed successfully using Overstitch, with satisfactory gastric distension and no gas leakage afterward.

CONCLUSION

The current experiment demonstrated the feasibility and safety of a totally endoscopic approach for the treatment of gastric submucosal tumors: full-thickness resection with the MASTER and successful closure of the defect using Overstitch.

A randomized controlled trial evaluating endoscopic and laparoscopic training in skills transfer for novices performing a simulated NOTES task

BACKGROUND

The NOSCAR white paper lists training as an important step to the safe clinical application of natural orifice translumenal endoscopic surgery (NOTES). The aim of this randomized controlled trial was to evaluate whether training novices in either a laparoscopic or endoscopic simulator curriculum would affect performance in a NOTES simulator task.

METHODS

A total of 30 third-year medical undergraduates were recruited. They were randomized to 3 groups: no training (control; n = 10), endoscopy training on a validated colonoscopy simulator protocol (n = 10), and training on a validated laparoscopy simulator curriculum (n = 10). All participants subsequently completed a simulated NOTES task, consisting of 7 steps, on the ELITE (endoscopic-laparoscopic interdisciplinary training entity) model. Performance was assessed as time taken to complete individual steps, overall task time, and number of errors.

RESULTS

The endoscopy group was significantly faster than the control group at accessing the peritoneal cavity through the gastric incision (median 27 vs 78 s; P = .015), applying diathermy to the base of the appendix (median 103.5 vs 173 s; P = .014), and navigating to the gallbladder (median 76 vs 169.5 s; P = .049). Endoscopy participants completed the full NOTES procedure in a shorter time than the laparoscopy group (median 863 vs 2074 s; P < .001).

CONCLUSION

This study highlights the importance of endoscopic training for a simulated NOTES task that involves both navigation and resection with operative maneuvers. Although laparoscopic training confers some benefit for operative steps such as applying diathermy to the gallbladder fossa, this was not as beneficial as training in endoscopy.

Innovative noninsufflation EFTR: sufficient endoscopic operative field by mechanical counter traction device

BACKGROUND

No reliable pure natural orifice transluminal endoscopic surgery (NOTES) mechanical counter traction (MCT) device for the flexible endoscope to obtain a sufficient surgical endoscopic field has yet been developed. Our experience with 10 cases of hybrid NOTES prompted the realization of the importance of an MCT device for the flexible endoscope and inspired us to establish innovative noninsufflation endoscopic full-thickness resection (EFTR) with an MCT device.

METHODS

We performed 40 EFTR 40 mm in diameter on excised whole porcine stomachs. Twenty were resected by an MCT device to obtain a surgical field (MCT group), and another 20 were resected with a conventional endoscopic attachment (control group). We evaluated the successful resection rates of EFTR and procedure times between two groups. Next, we implemented EFTR with a custom prototype MCT device in three cases of stomach pseudotumors in female dogs. Gastric pseudotumors ~40 mm in diameter were marked within the open surgical field created by the MCT device. After resecting the pseudotumors, we conducted full-thickness suturing using over-the-scope clips.

RESULTS

In the MCT group, all 20 cases were completely resected. On the other hand, in the control group, only 8 cases were performed via EFTR (P < 0.01). The mean ± standard deviation EFTR procedure times for the MCT and control groups were 4.13 ± 0.824 and 36.26 ± 8.67 min, respectively (P = 0.001). In three dogs, sufficient surgical working spaces were obtained up to 78 mm (range, 65-78 mm), and full-thickness resections were performed safely and sutured with over-the-scope clips.

CONCLUSIONS

Our new prototype MCT device effectively obtains a sufficient surgical endoscopic field during EFTR. We are developing a new MCT with a bending function to perform EFTR in any location in the stomach.

Design of a Multitasking Robotic Platform with Flexible Arms and Articulated Head for Minimally Invasive Surgery

This paper describes a multitasking robotic platform for Minimally Invasive Surgery (MIS). The device is designed to be introduced through a standard trocar port. Once the device is inserted to the desired surgical site, it can be reconfigured by lifting an articulated section, and protruding two tendon driven flexible arms. Each of the arms holds an interchangeable surgical instrument. The articulated section features a 2 Degrees-of-Freedom (DoF) universal joint followed by a single DoF yaw joint. It incorporates an on-board camera and LED light source at the distal end, leaving a Ø3mm channel for an additional instrument. The main shaft of the robot is largely hollow, leaving ample space for the insertion of two tendon driven flexible arms integrated with surgical instruments. The ex-vivo and in-vivo experiments demonstrate the potential clinical value of the device for performing surgical tasks through single incision or natural orifice transluminal procedures.

Endoscopic therapy for gastric stromal tumors originating from the muscularis propria

AIM: To explore endoscopic therapy methods for gastric stromal tumors originating from the muscularis propria.

METHODS: For 69 cases diagnosed as gastric stromal tumors originating from the muscularis propria, three types of endoscopic therapy were selected, based on the size of the tumor. These methods included endoscopic ligation and resection (ELR), endoscopic submucosal excavation (ESE) and endoscopic full-thickness resection (EFR). The wound surface and the perforation of the gastric wall were closed with metal clips. Immunohistostaining for CD34, CD117, Dog-1, S-100 and smooth muscle actin (SMA) was performed on the resected tumors.

RESULTS: A total of 38 cases in which the tumor size was less than 1.2 cm were treated with ELR; three cases were complicated by perforation, and the perforations were closed with metal clips. Additionally, 18 cases in which the tumor size was more than 1.5 cm were treated with ESE, and no perforation occurred. Finally, 13 cases in which the tumor size was more than 2.0 cm were treated with EFR; all of the cases were complicated by artificial perforation, and all of the perforations were closed with metal clips. All of the 69 cases recovered with medical treatment, and none required surgical operation. Immunohistostaining demonstrated that among all of the 69 gastric stromal tumors diagnosed by gastroscopy, 12 cases were gastric leiomyomas (SMA-positive), and the other 57 cases were gastric stromal tumors.

CONCLUSION: Gastric stromal tumors originating from the muscularis propria can be treated successfully with endoscopic techniques, which could replace certain surgical operations and should be considered for further application.

A technical review of flexible endoscopic multitasking platforms

BACKGROUND

Further development of advanced therapeutic endoscopic techniques and natural orifice translumenal endoscopic surgery (NOTES) requires a powerful flexible endoscopic multitasking platform.

METHODS

Medline search was performed to identify literature relating to flexible endoscopic multitasking platform from year 2004-2011 using keywords: Flexible endoscopic multitasking platform, NOTES, Instrumentation, Endoscopic robotic surgery, and specific names of various endoscopic multitasking platforms. Key articles from articles references were reviewed.

RESULTS

Flexible multitasking platforms can be classified as either mechanical or robotic. Purely mechanical systems include the dual channel endoscope (DCE) (Olympus), R-Scope (Olympus), the EndoSamurai (Olympus), the ANUBIScope (Karl-Storz), Incisionless Operating Platform (IOP) (USGI), and DDES system (Boston Scientific). Robotic systems include the MASTER system (Nanyang University, Singapore) and the Viacath (Hansen Medical). The DCE, the R-Scope, the EndoSamurai and the ANUBIScope have integrated visual function and instrument manipulation function. The IOP and DDES systems rely on the conventional flexible endoscope for visualization, and instrument manipulation is integrated through the use of a flexible, often lockable, multichannel access device. The advantage of the access device concept is that it allows optics and instrument dissociation. Due to the anatomical constrains of the pharynx, systems are designed to have a diameter of less than 20 mm. All systems are controlled by traction cable system actuated either by hand or by robotic machinery. In a flexible system, this method of actuation inevitably leads to significant hysteresis. This problem will be accentuated with a long endoscope such as that required in performing colonic procedures. Systems often require multiple operators. To date, the DCE, the R-Scope, the IOP, and the Viacath system have data published relating to their application in human.

CONCLUSION

Alternative forms of instrument actuation, camera control and master console ergonomics should be explored to improve instrument precision, sphere of action, size and minimize assistance required.