Development of an image-based Random Forest classifier for prediction of surgery duration of laparoscopic sigmoid resections

PURPOSE

Sigmoid diverticulitis is a disease with a high socioeconomic burden, accounting for a high number of left-sided colonic resections worldwide. Modern surgical scheduling relies on accurate prediction of operation times to enhance patient care and optimize healthcare resources. This study aims to develop a predictive model for surgery duration in laparoscopic sigmoid resections, based on preoperative CT biometric and demographic patient data.

METHODS

This retrospective single-center cohort study included 85 patients who underwent laparoscopic sigmoid resection for diverticular disease. Potentially relevant procedure-specific anatomical parameters recommended by a surgical expert were measured in preoperative CT imaging. After random split into training and test set (75% / 25%) multiclass logistic regression was performed and a Random Forest classifier was trained on CT imaging parameters, patient age, and sex in the training cohort to predict categorized surgery duration. The models were evaluated in the test cohort using established performance metrics including receiver operating characteristics area under the curve (AUROC).

RESULTS

The Random Forest model achieved a good average AUROC of 0.78. It allowed a very good prediction of long (AUROC = 0.89; specificity 0.71; sensitivity 1.0) and short (AUROC = 0.81; specificity 0.77; sensitivity 0.56) procedures. It clearly outperformed the multiclass logistic regression model (AUROC: average = 0.33; short = 0.31; long = 0.22).

CONCLUSION

A Random Forest classifier trained on demographic and CT imaging biometric patient data could predict procedure duration outliers of laparoscopic sigmoid resections. Pending validation in a multicenter study, this approach could potentially improve procedure scheduling in visceral surgery and be scaled to other procedures.

Toward telemedical diagnostics-clinical evaluation of a robotic examination system for emergency patients

Introduction

The SARS-CoV-2 pandemic has affected global public healthcare for several years. Numerous medical professionals have been infected since the outbreak in 2019, resulting in a shortage of healthcare providers. Since traditional personal protective wear was insufficient to eliminate the virus transmission reliably, new strategies to avoid cross-infection were imperative while enabling high-quality medical care. In the project ProteCT, we investigated the potential of robotic-assisted examination in providing medical examination via a telemedical approach.

Material and Methods

We constructed a fully functional examination cabin equipped with cameras, microphones, screens and robotic arms to evaluate usability and perception. Therefore, we conducted a preliminary study with 10 healthy volunteers and 10 physicians to gain first insights and optimize the setup. In a second step, we performed telemedical examinations of actual patients from the local emergency department to compare the robotic approach with the classical method of measuring vital signs, auscultation, palpation and percussion.

Results

The preliminary study identified basic requirements, such as the need for force-feedback and telemedical training for physicians. In the main study, acceptance was high and most patients indicated they would use a telemedical system again. Our setup enabled the physician to make the same diagnoses as by classic examination in the emergency department in most cases.

Discussion

The potential acceptance of a telemedical system such as ProteCT is high. Robotic telemedical approaches could complement future healthcare beyond the Corona pandemic to reach rural areas or even war zones. Moreover, the daily clinical use of robotic telemedicine could improve patients' safety, the quality of perioperative management and the workflow in any medical facility.

Conclusion

The development of telemedical and telerobotic systems is a multidisciplinary and complex challenge. However, acceptance of the proposed system was high among patients and physicians, indicating the potential use of similar systems for future healthcare.

The impact of prior endoscopic or surgical therapy on open Zenker's diverticulum surgery: analysis on a large single center cohort : Comparison of primary and revisional open surgery for Zenker's diverticulum

BACKGROUND

Endoscopic treatment of Zenker's diverticulum is an attractive minimally invasive alternative compared to the classic open approach. However, increased recurrence rate were reported. In case of relapse, endoscopic therapy might be repeated, or alternatively open surgery is performed. This study aimed to identify potential differences in the outcomes between primary or secondary surgical treatment in Zenker's diverticulum.

METHODS

From January 2003 to April 2019, 227 subsequent patients underwent surgical diverticulectomy and cervical myotomy at the surgical department of TUM. 41 of 227 patients had received previous therapy, either open or endoscopic. Perioperative parameters in priorly untreated patients were retrospectively compared to those after previous therapy (mostly endoscopic) with special regard to perioperative data and postoperative complications. Univariate and multivariate regression analyses were performed to identify predictors for postoperative complications.

RESULTS

We could show that the number of complications (p = 0.047) in pretreated patients is significant higher as well as the severity after Clavien-Dindo (p = 0.025). Stapler line leakage, wound infections, and operative revision rate was higher also pretreated group. Pretreatment and surgery time showed a significant association with postoperative complications in univariate analysis. In multivariate analysis, pretreatment remained a significant independent predictor of complications.

CONCLUSION

The present data indicate that endoscopic therapy might represent a risk factor for postoperative complications in case of relapse surgery. Therefore primary open surgery should be debated in patients with an increased high risk of relapse.

Long-term outcome of patients with epiphrenic diverticula: A retrospective single-center analysis over 20 years

BACKGROUND

Epiphrenic diverticula are extremely rare. Evidence-based treatment recommendations are scarce. The primary study outcome was to examine whether surgical treatment in patients with epiphrenic diverticula leads to improved quality of life by outweighing the perioperative risks compared with conservative treatment.

METHODS

All patients with an epiphrenic diverticula at our institution between 2001 and 2021 were retrospectively reviewed and followed-up using a specific questionnaire, including the Eating Assessment Tool, and Gastrointestinal Quality of Life Index quality-of-life scores.

RESULTS

Of 51 patients with epiphrenic diverticula, 28 had surgery and 23 had conservative treatment. The most common symptom at presentation was dysphagia. Although 16 patients underwent open surgery, 12 had minimally invasive procedures. A prophylactic stent was applied intraoperatively in 6 patients. The morbidity rate in surgically treated patients was 50% (14/28), with a leakage in 43% (12/28; 33% for prophylactic stenting). Mortality was nil. At a median follow-up of 139 months, patients with surgery had better outcomes than those without (ie, less dysphagia [6/12 vs 11/12; P = .025]), a less likely pathologic Eating Assessment Tool score (4/12 vs 9/12; P = .041), and a nonsignificant better Gastrointestinal Quality of Life Index score (122 vs 112; P = .929). The rate of recurrence/progression of symptoms was significantly higher for conservatively treated patients (11/18 vs 6/27 for any surgery; P = .008), as well as for patients with minimally invasive procedure (5/12 vs 1/15 for open surgery; P = .030).

CONCLUSION

Despite the high perioperative morbidity, surgical treatment of epiphrenic diverticula leads to an improved long-term quality of life and lower recurrence rates than conservative treatment.

[Image-based supportive measures for future application in surgery]

BACKGROUND

The development of assistive technologies will become of increasing importance in the coming years and not only in surgery. The comprehensive perception of the actual situation is the basis of every autonomous action. Different sensor systems can be used for this purpose, of which video-based systems have a special potential.

METHOD

Based on the available literature and on own research projects, central aspects of image-based support systems for surgery are presented. In this context, not only the potential but also the limitations of the methods are explained.

RESULTS

An established application is the phase detection of surgical interventions, for which surgical videos are analyzed using neural networks. Through a time-based and transformative analysis the results of the prediction could only recently be significantly improved. Robotic camera guidance systems will also use image data to autonomously navigate laparoscopes in the near future. The reliability of the systems needs to be adapted to the high requirements in surgery by means of additional information. A comparable multimodal approach has already been implemented for navigation and localization during laparoscopic procedures. For this purpose, video data are analyzed using various methods and these data are fused with other sensor modalities.

DISCUSSION

Image-based supportive methods are already available for various tasks and will become an important aspect for the surgery of the future; however, in order to be able to be reliably implemented for autonomous functions, they must be embedded in multimodal approaches in the future in order to provide the necessary security.

Robotic Endoscope Control - State of the Art of Voice Control and Other Options for Laparoscopic Camera Robot Guidance

In video-based surgery (VBS), the surgeon is no longer the master of his or her view. Visualization of the surgical field is mediated by a video camera guided by an assistant. The separation of visualization and surgical activities leads to significant drawbacks. Early in the history of VBS, active camera holders controlled directly by the surgeon were introduced to replace the human camera assistant. However, despite remarkable technological advances over the past 25 years, robotic camera guidance systems (RCGS) still play only a marginal role. This is less due to inadequate mechanical designs or kinematics, and mainly due to inadequate human-machine interaction. In most cases, a simple task-shift is required that increases the surgeon's mental workload instead of reducing it. The current state of the art in robotic camera guidance, as represented by the SOLOASSIST II RCGS (AKTORmed, Neutraubling, Germany), includes a sophisticated combination of direct manual control, joystick navigation and high-quality voice control that provides the most intuitive surgeon-machine interaction currently available. An in-depth analysis of further clinical needs and promising developments in operating room integration suggests that the addition of context sensitivity could actually enhance the assistive effect of RCGS, making them potentially superior to the average human camera guidance.

Surgical data science - from concepts toward clinical translation

Recent developments in data science in general and machine learning in particular have transformed the way experts envision the future of surgery. Surgical Data Science (SDS) is a new research field that aims to improve the quality of interventional healthcare through the capture, organization, analysis and modeling of data. While an increasing number of data-driven approaches and clinical applications have been studied in the fields of radiological and clinical data science, translational success stories are still lacking in surgery. In this publication, we shed light on the underlying reasons and provide a roadmap for future advances in the field. Based on an international workshop involving leading researchers in the field of SDS, we review current practice, key achievements and initiatives as well as available standards and tools for a number of topics relevant to the field, namely (1) infrastructure for data acquisition, storage and access in the presence of regulatory constraints, (2) data annotation and sharing and (3) data analytics. We further complement this technical perspective with (4) a review of currently available SDS products and the translational progress from academia and (5) a roadmap for faster clinical translation and exploitation of the full potential of SDS, based on an international multi-round Delphi process.

Telemedical percussion: objectifying a fundamental clinical examination technique for telemedicine

Purpose

While demand for telemedicine is increasing, patients are currently restricted to tele-consultation for the most part. Fundamental diagnostics like the percussion still require the in person expertize of a physician. To meet today’s challenges, a transformation of the manual percussion into a standardized, digital version, ready for telemedical execution is required.

Methods

In conjunction with a comprehensive telemedical diagnostic system, in which patients can get examined by a remote-physician, a series of three robotic end-effectors for mechanical percussion were developed. Comprising a motor, a magnetic and a pneumatic-based version, the devices strike a pleximeter to perform the percussion. Emitted sounds were captured using a microphone-equipped stethoscope. The 84 recordings were further integrated into a survey in order to classify lung and non-lung samples.

Results

The study with 21 participants comprised physicians, medical students and non-medical-related raters in equal parts. With 71.4% correctly classified samples, the ventral motorized device prevailed. While the result is significantly better compared to a manual or pneumatic percussion in this very setup, it only has a small edge over the magnetic devices. In addition, for all ventral versions non-lung regions were rather correctly identified than lung regions.

Conclusion

The overall setup proves the feasibility of a telemedical percussion. Despite the fact, that produced sounds differ compared to today’s manual technique, the study shows that a standardized mechanical percussion has the potential to improve the gold standard’s accuracy. While further extensive medical evaluation is yet to come, the system paves the way for future uncompromised remote examinations.

New Method for Surgical Diagnostics - a Robotic Telemedical Approach

Apart from the tremendous increase in the demand for telemedicine during the COVID-19 pandemic, the use of telemedical technology offers many advantages, such as better coverage of rural areas and improved access to specialists. While current telediagnostic possibilities are often limited to a verbal consultation, the field of surgery has already made use of robotics for one of the most challenging areas of medicine: invasive procedures. Since comprehensive diagnostics are a prerequisite for each surgery, we built upon the knowledge gained in telesurgery and developed a telediagnostic system that allows for an extensive perioperative and emergency examination. It is based on a robotic platform consisting of a remote lead robotic arm at the physician's site and a follower robot at the patient's site. Mirroring all movements directly and using force-feedback, both parties can precisely interact, enabling tasks such as auscultation, percussion, and palpation without the need for extensive training. Our overall setup also includes the possibility to measure and monitor all relevant vital parameters and can be used to perform ear and nasopharyngeal inspections as well as an automatic swab to screen for COVID or other contagious diseases prior to hospital admission. In this paper, we focus on the potential of this technology for the surgical community by demonstrating the ease of adding an ultrasound probe to our modular setup to perform a high-quality emergency ultrasound examination. While the system is not yet ready for everyday use in a hospital and drawbacks such as a high cost persist, our setup paves the way for the future use of telediagnostics in surgery.

“Hybrid” scientific conference: lessons learned from the digital annual meeting of the CARS international conference during the Covid-19 pandemic

Objectives

Due to the coronavirus disease 2019 (Covid-19) pandemic, all scientific conferences in the year 2020 had to be adapted in their form of presence to accommodate for safety regulations, postponed, or canceled entirely. As organizers of the annual Computer Assisted Radiology & Surgery International Conference & Exhibition (CARS)-Conference 2020, we decided to hold a “hybrid” conference, i.e., a virtual conference with partial presence to mitigate the drawbacks of a purely virtual conference. It is the purpose of this paper to describe the results and experience gained by our first hybrid conference.

Methods

Besides technical necessities like an online conferencing tool, we introduced additional personal namely the technical chairs and communication officers ensuring a smooth flow of presentations. To measure the success of the hybrid conference, we assessed various parameters during the conference (e.g., counting of adverse events, delays, and no-shows) and sent a questionnaire to participants for evaluation after the conference.

Results

We offered four types of presentation formats, whereas the majority of speakers presented their pre-produced videos including live discussions. Significant delays in sessions occurred during the morning sessions, which could be reduced during lunch breaks. The analysis of the influence of the distribution of the audience’s location/time zone toward the attendance rate showed a high relevance for the American zone and only little influence for the Asian-Pacific region. Based on the questionnaire, 60% of responders considered the hybrid approach as superior and 12% as inferior to purely virtual conferences.

Conclusions

Most scientific associations in 2020 had to struggle with a dramatic change: Regular, traditional meetings with personal communication and exchange, networking, and creation of new visions became obsolete almost instantly. As an alternative, virtual conferences became increasingly popular, and are offering additional advantages (e.g., reduction of cost for travel, lodging, and time on transit). To overcome the drawbacks of purely virtual conferences, we introduced a hybrid concept for the CARS-Congress. While certainly, those with the privilege to take part personally on-site did benefit most from the hybrid format. Facing upcoming waves of the Covid-19 Pandemic, with ongoing changes to the regulations on meetings and transit, hybrid conferences are a viable option for scientific conferences for the future.

Acting in a Robotic Environment Requires New Skills for Physicians

In context of the Corona pandemic, telemedicine acquired a new significance. Whereas previously the aim was to override given barriers, now, in the case of a pandemic, the main idea is to create an intentional distance between patients and healthcare professionals in order to avoid cross-infection. To meet the needs of a fully diagnostic examination, a robotic based system was designed. However, collaborative robotic systems bear new risks, that have to be dealt with. To prepare future physicians for telediagnostics, we developed a training curriculum for the telemedical examinations. It is based upon multiple stages including a skill trainer, healthy volunteers, supervised examinations of real patients and an exam. In a first proof of concept, we demonstrated the existence of a learning curve and significant better performance after the passed curriculum compared to an untrained collective.

Evaluation of improved bi-manual endoscopic resection using a customizable 3D-printed manipulator system designed for use with standard endoscopes: a feasibility study using a porcine ex-vivo model

Background and study aims  A major drawback of endoscopic en-bloc resection technique is its inability to perform bimanual tasks. Although endoscopic platforms that enable bimanual tasks are commercially available, they are neither approved for various locations nor adaptable to specific patients and indications. Methods  Based on evolution of an adaptive 3D-printable platform concept, system variants with different characteristic properties were evaluated for ESD scenarios, ex-vivo in two locations in the stomach and colorectum. Results  In total 28 ESDs were performed (7 antrum, 7 corpus in inversion, 7 cecum, 7 rectum) in a porcine ex-vivo setup. ESD was feasible in 21 cases. Investigated manipulator variants are differently well suited for performing ESD within the varying interventions scenarios. Dual-arm manipulators allowed autonomous ESD, while single-arm flexible manipulators could be used more universally due to their compact design, especially for lesions difficult to access. Pediatric scopes were too frail to guide the overtube-manipulators in extremely angled positions. Working in the rectum was impaired using long-sized manipulator arms. Conclusions  The presented endoscopic platform based on 3D-printable and customizable manipulator structures might be a promising approach for future improvement of ESD procedure. With regard to localization, especially flexible manipulators attached to standard endoscopes appear to be most promising for further application of specific and individualised manipulator systems.

Machine Learning in the OR: A Collaborative Environment for Surgical Interventions in Visceral Medicine

Modern surgical methods are becoming increasingly sophisticated and the number of technical devices that are used during these interventions is increasing. However, the surgical operating room (OR) remains a mere conglomerate of unconnected medical devices. The increase in the complexity of device functionality, in addition to the demands of surgery, pushes human mental capacity to its limit. Hence, an "intelligent" collaborative support system would be more than welcome. We envision a "human-like" intelligent system, which could support the surgical team as a situation-aware consultant. This so-called "active collaborative support system" (ACSS) is based on four main pillars: real-time data inflow, a comprehensive knowledge-base, access to the Internet of Things (surgical devices), and an understanding of human language through natural language processing. Recent advances in the area of AI are bringing this ambitious goal within reach, but there is still a considerable amount of work to be done, including the establishment of a new way of thinking in the collaboration between surgeons and computer scientists/engineers, and possibly one day with intelligent machines-provided that AI systems can be sufficiently trusted.

New insights in diagnostic laparoscopy

The basic concept of Diagnostic Laparoscopy (DL) is old but not old-fashioned. – Before the rise of tomography and ultrasound there was just the direct look into the abdomen and onto the affected organ available. As open surgery comes along with trauma, blood loss and infection, every effort have been made to improve the access strategies. Finally, due to innovation in optics, video technology and computer science, the look into the abdomen through a “keyhole” is a standard procedure today. – In this review we give an overview of history, implications and cost-effectiveness of DL, attempting an extrapolation of its future role.

Acoustic signal analysis of instrument-tissue interaction for minimally invasive interventions

Purpose

Minimally invasive surgery (MIS) has become the standard for many surgical procedures as it minimizes trauma, reduces infection rates and shortens hospitalization. However, the manipulation of objects in the surgical workspace can be difficult due to the unintuitive handling of instruments and limited range of motion. Apart from the advantages of robot-assisted systems such as augmented view or improved dexterity, both robotic and MIS techniques introduce drawbacks such as limited haptic perception and their major reliance on visual perception.

Methods

In order to address the above-mentioned limitations, a perception study was conducted to investigate whether the transmission of intra-abdominal acoustic signals can potentially improve the perception during MIS. To investigate whether these acoustic signals can be used as a basis for further automated analysis, a large audio data set capturing the application of electrosurgery on different types of porcine tissue was acquired. A sliding window technique was applied to compute log-mel-spectrograms, which were fed to a pre-trained convolutional neural network for feature extraction. A fully connected layer was trained on the intermediate feature representation to classify instrument–tissue interaction.

Results

The perception study revealed that acoustic feedback has potential to improve the perception during MIS and to serve as a basis for further automated analysis. The proposed classification pipeline yielded excellent performance for four types of instrument–tissue interaction (muscle, fascia, liver and fatty tissue) and achieved top-1 accuracies of up to 89.9%. Moreover, our model is able to distinguish electrosurgical operation modes with an overall classification accuracy of 86.40%.

Conclusion

Our proof-of-principle indicates great application potential for guidance systems in MIS, such as controlled tissue resection. Supported by a pilot perception study with surgeons, we believe that utilizing audio signals as an additional information channel has great potential to improve the surgical performance and to partly compensate the loss of haptic feedback.

5th-Generation Mobile Communication: Data Highway for Surgery 4.0

INTRODUCTION

5th generation cellular mobile communications (5G) is one of the main requirements for the digital future. The new standard will offer high bandwidths (10GB/s), low latency (<1ms), and a high quality of service. It is not yet known whether 5G performance is sufficient for demanding eHealth applications (e.g., telemedicine).

MATERIAL AND METHODS

We evaluated 5G performance in two different medical applications (person/asset track & tracing and video data transmission for telesurgery) to appraise the impact of this new technology. In addition, a Delphi study was conducted evaluating the expectations and acceptance of 5G in the medical field in general.

RESULTS

Delphi study revealed that 5G has great potential for the future information transfer in the healthcare domain, and an increase of research activities for 5G applications in hospitals is needed. Clinical evaluation proved technical feasibility and accuracy of the 5G track & trace prototype solution. For the telepresence use case, the video stream data rate varied between 900KB-1MB/s (7.2-8 Mb/s). The data rate of the robotic control command varied between 2.4-7.2KB/s (19.2-57.6Kb/s). Delay time (latency) ranged between 2-60ms depending on the transmitted data packet length. Seventy-five percent of data packets were processed after 30ms.

CONCLUSION

5G data transmission volume, rate, and latency met the requirements for real-time track & trace and telemedicine applications. Especially for the latter, 5G data transmission offers a high potential and further research should be carried out.

Mechatronic Support System for NOTES and Monoport Surgery - A New Approach

To circumvent the drawbacks of currently available platforms for natural orifice transluminal endoscopic surgery (NOTES) and monoport surgery (MPS), we developed a patient-specific, disposable, surgical soft robotic system. The system (Single-Port Overtube; SPOT) is designed as an overtube for standard surgical equipment. The platform body and the manipulators can be quickly adapted to transmural (monoport), NOTES and endoluminal (endoscopic) applications, and 3D-printed overnight as an individualized system. In addition, practical considerations, such as the predicted "ideal" dimensions of the platform, were evaluated. As a result, we found that preoperatively available biometric data currently provide little support for tailored instrument design. Further work is required to provide engineers / developers with more useful preoperative information.

24-hour monitoring of transient lower esophageal sphincter relaxation events by long-term high-resolution impedance manometry in normal volunteers: The "mirror phenomenon"

BACKGROUND

The aim of this study was to investigate the frequency and circadian changes in transient lower esophageal sphincter relaxations (TLESRs) in normal volunteers using 24-hour high-resolution impedance manometry (HRIM).

METHODS

Fifteen volunteers underwent HRIM. TLESRs were recorded during the mealtime, 2-hour postprandial, daytime, and supine periods. The catheter was firmly secured to the nose, and subjects went home, ate normal meals, and continued routine daily activities.

KEY RESULTS

Successful recordings were obtained in 11 volunteers. Overall, 1083 TLESRs were documented; the average occurrence was 4.2/h, and the duration was 21.0 ± 5.2 seconds. The majority of the TLESRs occurred during the 2-hour postprandial (42.7%) and daytime (31.5%) periods, while 10.2% and 15.6% occurred during the mealtime and supine periods, respectively. Eight hundred and eighty-six (81.8%) TLESRs were associated with reflux. Overall, 25.5% of TLESRs were preceded by partial secondary peristalsis (PSP), while 74.5% were preceded by nothing. Terminating events included primary peristalsis (PP; 40.3%), PSP (42.8%), full secondary peristalsis (FSP; 8.2%), or nothing (8.7%). Both preceding and terminating events periodically changed throughout the four periods. One hundred and twelve (10.3%) TLESRs with both preceding and terminating events of PSP, presenting as a "mirror phenomenon," were documented. The majority of these TLESRs occurred during the supine (70.5%).

CONCLUSIONS & INFERENCES

Transient lower esophageal sphincter relaxations are common physiological motor events in normal volunteers; these events have certain circadian rhythms, as do the events that precede and terminate TLESR events. A special "mirror phenomenon" is observed when both the preceding and terminating events are PSP.

Informatics and Medicine

Objectives: To clarify challenges and research topics for informatics in health and to describe new approaches for interdisciplinary collaboration and education. Methods: Research challenges and possible solutions were elaborated by scientists of two universities using an interdisciplinary approach, in a series of meetings over several months. Results and Conclusion: In order to translate scientific results from bench to bedside and further into an evidence-based and efficient health system, intensive collaboration is needed between experts from medicine, biology, informatics, engineering, public health, as well as social and economic sciences. Research challenges can be attributed to four areas: bioinformatics and systems biology, biomedical engineering and informatics, health informatics and individual healthcare, and public health informatics. In order to bridge existing gaps between different disciplines and cultures, we suggest focusing on interdisciplinary education, taking an integrative approach and starting interdisciplinary practice at early stages of education.

* See more detailed authors´ affiliations at the end of the article.

Endoluminal Sphincter Augmentation with the MUSE™ System and GERDX™ System in the Treatment of Gastroesophageal Reflux Disease: A New Impact?

To bridge the gap between the long-term intake of proton pump inhibitors (PPIs) and the potential risks of laparoscopic fundoplication, a number of endoscopic procedures for the treatment of gastro-esophageal reflux disease (GERD) have been developed over the past 30 years. Because of the minimally invasive approach, short operative time, and efficacy in selected patients, endoluminal sphincter augmentation appears to be highly attractive. However, most early devices have proven to be unsafe or failed to provide long-term symptom relief. Accordingly, products for endoluminal sphincter augmentation have undergone several modifications to achieve an increased lower esophageal sphincter (LES) baseline pressure to re-establish the LES as an efficacious anti-reflux barrier. This paper reviews and discusses the two latest products for endoluminal sphincter augmentation, the MUSE™ device (Medigus, Ltd., Omer, Israel) and the GERDX™ system (G-SURG GmbH, Seeon-Seebruck, Germany). While the currently available literature has proven their effectiveness in principle, long-term results are lacking. Further studies and developments are necessary to determine whether these two new devices will truly impact GERD therapy.

Endoscopic rendez-vous reconstruction of complete biliary obstruction

BACKGROUND AND STUDY AIMS

Complete biliary strictures normally require surgical intervention. We describe an alternative, minimally invasive endoscopic/percutaneous rendez-vous technique for the reconstruction of complete benign biliary strictures.

PATIENTS AND METHODS

Complete biliary strictures were reconstructed in four patients using a rendez-vous percutaneous-endoscopic or percutaneous-percutaneous route guided by fluoroscopic and visual (transillumination) control.

RESULTS

All four patients were treated successfully and safely with the rendez-vous technique. Complications were caused by the preliminary creation, dilatation and maturation of the percutaneous tract.

CONCLUSION

This technique may offer a good alternative to surgical bilio-enteric anastomosis in experienced hands. The long term course of the patients treated remains to be seen.

An evaluation of a surgical telepresence system for an intrahospital local area network

summary

We evaluated a digital telepresence system in an operating theatre (OR) environment which enabled a consultant to join the surgical team from a remote site by audiovisual communication. The system is based on video transmission using a streaming technique, with a server and a client connected via a local area network (LAN). Two cameras can be remotely controlled: one camera is built into the OR lamp and a second, laparoscopic camera is mounted on a robotic arm. Another feature of the system is teledemonstration, which permits the remote consultant to demonstrate points of particular interest. We evaluated the system clinically in 237 cases. In 28 cases (12%), telepresence could not be established for various reasons, mainly human failure. In 42 cases (18%), the full potential of telepresence was used. Technical evaluation showed that a data rate of 2 Mbit/s provides sufficient audio and video quality, as well as reliable teledemonstration. The data transmission delay was acceptable for clinical purposes (video 0.92 s, audio 0.6s from OR to client, audio 0.7s from client to OR). The study showed that telepresence is a promising means of providing highly specialized expertise within the OR.

Esophageal bougination: a novel ex vivo endoscopic training model correlated with clinical data

BACKGROUND

Esophageal bougination is a worldwide standard endoscopic procedure. Clinical methods and recommendations are based on clinical experiences only. Mechanical properties have never been described. Aim of the study was to establish a realistic ex vivo training model. Therefore, detailed assessment of relevant mechanical features of esophageal bougination should be evaluated ex vivo and in patient setting and correlated against.

PATIENTS AND METHODS

A three-step concept was used to evaluate mechanical properties at stenosis level. First, insertion forces were evaluated in an ex vivo linear single stenosis model during steady mechanical insertion. Second, adding friction and properties of the pharynx and upper esophagus, the model was integrated in an artificial endoscopic training model (ELITE training model). Third, in vivo measurements were taken to correlate ex vivo data with parameters of a realistic patient setting.

RESULTS

With the presented setup, we were able to assess insertion force and pressure levels in an artificial stricture using different sizes of commercially available standard bougies. In all models, there was a relevant increase in insertion force with higher stricture pressure levels. Insertion force levels in the ELITE model show higher levels compared to the linear stenosis model. Having regard to the maximum forces in patients, there is also a constant increase in mean insertion force according to higher bougie sizes, but lower forces were measured as in the ELITE model.

DISCUSSION

The applied models are suitable to appraise mechanical properties of esophageal bougination in an ex vivo model and patient setting. Forces could be constituted reliable, significant increase was documented according to stenosis level and results were comparable to patient data. This was comparable to patient data. Further clinical evaluation in different kinds of stenosis is necessary.

Wireless live streaming video of surgical operations: an evaluation of communication quality

We evaluated a mobile video system for surgical teleconsultation. A video streaming server in the operating room transmitted video and audio to a hand-held computer (personal digital assistant [PDA]) over a wireless local area network. Two groups of 20 surgeons (each with 12 qualified surgeons and eight surgeons between the 2nd and the 4th year of training) participated in the tests. For voice transmission, correct understanding of numbers was achieved in 100% of the cases ( n = 1000) and 98% of medical terms ( n = 400). The quality of the video displayed on the PDA was assessed by the recognition of different operating room scenarios. Only 62% (SD 17) of the structures were identified clearly on the hand-held device ( n = 400). The accuracy improved to 78% (SD 15) ( n = 400) if the same scenario was observed on a larger (50 cm) video screen ( p < 0.001). Accuracy was significantly better if audio conversation was possible. The quality evaluation by the consultants showed that the PDA display size and quality were sufficient for clinical use.

Pharyngeal pH monitoring in gastrectomy patients - what do we really measure?

AIM

Diagnosis of laryngopharyngeal reflux (LPR) has dramatically increased over the last years. For diagnosis of gastroesophageal reflux, a newly designed pharyngeal probe (Dx-pH) was recently introduced. It is also recommended to guide therapy decision in antireflux surgery. However, diagnostic results are questionable. Therefore, we establish a reliable reference group with asymptomatic patients after total gastrectomy and, thus, complete extinction of gastric acid production.

METHODS

Pharyngeal pH monitoring was performed in 10 consecutive patients with history of total gastrectomy. All patients were off proton pump inhibitor (PPI) therapy and followed a non-acid diet during the complete measurement period.

RESULTS

All procedures were performed without any complication. Six of the 10 asymptomatic gastrectomy patients (60%) had pathological results derived from the validated reference values (Ryan score) in pharyngeal pH monitoring.

CONCLUSION

Pathological pH values assessed by the Dx-pH device, usually interpreted as pathological aerosolized acidic gastroesophageal and/or laryngopharyngeal reflux, are obviously dissociated from gastric acid production. Further studies are required to determine diagnostic value of the new system. Therefore, the pharyngeal pH monitoring system seems currently not to be useful to guide any diagnostic or therapeutic decisions, in particular if surgical therapy is considered.

Endoluminal perforation of a magnetic antireflux device

BACKGROUND

The history of surgical antireflux treatment is coined by the search for better alternatives to Nissen fundoplication. Implantable devices are one option, beginning with the "Angelchik" prosthesis 30 years ago. However, this procedure was left soon because of the high rate of foreign body connected problems (migration, perforation). A modern approach is a magnetic sphincter augmentation device (LINX Reflux Management System, Torax Medical, Shoreview, MN, USA), a magnetic chain which is implanted laparoscopically. Advantages reported are simplicity to apply and good results in reflux control, with up to now only rare complication rates as reported in the literature (Lipham et al. in Dis Esophagus, 2014).

METHODS

We report one case of erosion of the esophagus by a LINX system resulting in severe dysphagia.

RESULTS

A complete endoluminal removal could be achieved by a prototype OTSC-clip remover. Complete remission could be achieved. The technique is presented in detail (video).

CONCLUSIONS

In principle, total endoscopic removal of the LINX device is feasible in case of major erosion.

The "Iceberg Phenomenon": As Soon as One Technological Problem in NOTES Is Solved, the Next One Appears!

PURPOSE

Though already proclaimed about 7 years ago, natural orifice transluminal endoscopic surgery (NOTES) is still in its early stages. A multidisciplinary working team tried to analyze the technical obstacles and identify potential solutions.

METHODS

After a comprehensive review of the literature, a group of 3 surgeons, 1 gastroenterologist, 10 engineers, and 1 representative of biomedical industry defined the most important deficiencies within the system and then compiled as well as evaluated innovative technologies that could be used to help overcome these problems. These technologies were classified with regard to the time needed for their implementation and associated hindrances, where priority is based on the level of impact and significance that it would make.

RESULTS

Both visualization and actuation require significant improvement. Advanced illumination, mist elimination, image stabilization, view extension, 3-dimensional stereoscopy, and augmented reality are feasible options and could optimize visual information. Advanced mechatronic platforms with miniaturized, powerful actuators, and intuitive human-machine interfaces could optimize dexterity, as long as enabling technologies are used. The latter include depth maps in real time, precise navigation, fast pattern recognition, partial autonomy, and cognition systems.

CONCLUSION

The majority of functional deficiencies that still exist in NOTES platforms could be overcome by a broad range of already existing or emerging enabling technologies. To combine them in an optimal manner, a permanent dialogue between researchers and clinicians is mandatory.

Developments in flexible endoscopic surgery: a review

Flexible endoscopy is increasingly developing into a therapeutic instead of a purely diagnostic discipline. Improved visualization makes early lesions easily detectable and allows us to decide ad hoc on the required treatment. Deep enteroscopy allows the exploration of even the small bowel - for long a "white spot" for gastrointestinal endoscopy - and to perform direct treatment. Endoscopic submucosal dissection is a considerable step forward in oncologically correct endoscopic treatment of (early) malignant lesions. Though still technically challenging, it is increasingly facilitated by new manipulation techniques and tools that are being steadily optimized. Closure of wall defects and hemostasis could be improved significantly. Even the anatomy beyond the gastrointestinal wall is being explored by the therapeutic use of endoluminal ultrasound. Endosonographic-guided surgery is not only a suitable fallback solution if conventional endoscopic retrograde cholangiopancreatography fails, but even makes necrosectomy procedures, abscess drainage, and neurolysis feasible for the endoscopist. Newly developed endoscopic approaches aim at formerly distinctive surgical domains like gastroesophageal reflux disease, appendicitis, and cholecystitis. Combined endoscopic/laparoscopic interventional techniques could become the harbingers of natural orifice transluminal endoscopic surgery, whereas pure natural orifice transluminal endoscopic surgery is currently still in its beginnings.

What Do We Really Need? Visions of an Ideal Human-Machine Interface for NOTES Mechatronic Support Systems From the View of Surgeons, Gastroenterologists, and Medical Engineers

PURPOSE

To investigate why natural orifice translumenal endoscopic surgery (NOTES) has not yet become widely accepted and to prove whether the main reason is still the lack of appropriate platforms due to the deficiency of applicable interfaces.

METHODS

To assess expectations of a suitable interface design, we performed a survey on human-machine interfaces for NOTES mechatronic support systems among surgeons, gastroenterologists, and medical engineers. Of 120 distributed questionnaires, each consisting of 14 distinct questions, 100 (83%) were eligible for analysis.

RESULTS

A mechatronic platform for NOTES was considered "important" by 71% of surgeons, 83% of gastroenterologist,s and 56% of medical engineers. "Intuitivity" and "simple to use" were the most favored aspects (33% to 51%). Haptic feedback was considered "important" by 70% of participants. In all, 53% of surgeons, 50% of gastroenterologists, and 33% of medical engineers already had experience with NOTES platforms or other surgical robots; however, current interfaces only met expectations in just more than 50%. Whereas surgeons did not favor a certain working posture, gastroenterologists and medical engineers preferred a sitting position. Three-dimensional visualization was generally considered "nice to have" (67% to 72%); however, for 26% of surgeons, 17% of gastroenterologists, and 7% of medical engineers it did not matter (P = 0.018).

CONCLUSION

Requests and expectations of human-machine interfaces for NOTES seem to be generally similar for surgeons, gastroenterologist, and medical engineers. Consensus exists on the importance of developing interfaces that should be both intuitive and simple to use, are similar to preexisting familiar instruments, and exceed current available systems.

Design of a test system for the development of advanced video chips and software algorithms

BACKGROUND

Visual deterioration is a crucial point in minimally invasive surgery impeding surgical performance. Modern image processing technologies appear to be promising approaches for further image optimization by digital elimination of disturbing particles. To make them mature for clinical application, an experimental test environment for evaluation of possible image interferences would be most helpful.

METHODS

After a comprehensive review of the literature (MEDLINE, IEEE, Google Scholar), a test bed for generation of artificial surgical smoke and mist was evolved. Smoke was generated by a fog machine and mist produced by a nebulizer. The size of resulting droplets was measured microscopically and compared with biological smoke (electrocautery) and mist (ultrasound dissection) emerging during minimally invasive surgical procedures.

RESULTS

The particles resulting from artificial generation are in the range of the size of biological droplets. For surgical smoke, the droplet dimension produced by the fog machine was 4.19 µm compared with 4.65 µm generated by electrocautery during a surgical procedure. The size of artificial mist produced by the nebulizer ranged between 45.38 and 48.04 µm compared with the range between 30.80 and 56.27 µm that was generated during minimally invasive ultrasonic dissection.

CONCLUSION

A suitable test bed for artificial smoke and mist generation was developed revealing almost identical droplet characteristics as produced during minimally invasive surgical procedures. The possibility to generate image interferences comparable to those occurring during laparoscopy (electrocautery and ultrasound dissection) provides a basis for the future development of image processing technologies for clinical applications.

A probe-based electromagnetic navigation system to integrate computed tomography during upper gastrointestinal endoscopy

BACKGROUND AND STUDY AIMS

For preoperative work-up, an examination tool that visualizes separately compiled diagnostics in augmented reality would be desirable. We developed a probe-based electromagnetic navigation system, which can be passed through the working channel of an endoscope, to integrate computed tomography (CT) information during upper gastrointestinal endoscopy.

PATIENTS AND METHODS

The target registration error (TRE) of the system was evaluated experimentally and clinically. A total of 24 study patients with upper gastrointestinal cancer were included in the study. The cancerous lesion was endoscopically located (mean duration 8.4 minutes, range 7.1 - 23.2) and the TRE (coronal, transverse, sagittal layer) was measured by comparing the distance between the navigation probe (at the tip of the endoscope) and the target lesion shown on the corresponding CT cross section.

RESULTS

Experimental evaluations showed an accuracy in line with the system's inherent failure rate, with a median TRE of 2.8 mm (IQR 1.8 - 4.3), 2.2 mm (0.4 - 3.7), and 2.8 mm (1.1 - 5.9) in the coronal, transverse, and sagittal planes, respectively. Clinical evaluation revealed a median TRE of 4.8 mm (1.9 - 10.1), 3.9 mm (0.7 - 7.1), and 4.2 mm (0.9 - 8.9), respectively. No complications occurred during navigated endoscopy.

CONCLUSIONS

The probe-based electromagnetic navigation system revealed high accuracy (TRE < 5 mm), facilitating improved interpretation of endoluminal imaging.

[Further technical and digital development in minimally invasive and conventional surgery]

Technological innovations have initiated a fundamental change in invasive therapeutic approaches which has led to a welcome reduction of surgical trauma but was also associated with a declining role of conventional surgery. Active utilization of future technological developments is decisive to promote new therapeutic strategies and to avoid a further loss of importance of surgery. This includes individualized preoperative therapy planning as well as intraoperative diagnostic work-up and navigation and the use of new functional intelligent implants. The working environment "surgical operating room" has to be refurbished into an integrated cooperating functional system. The impact of new technological developments is particularly obvious in minimally invasive surgery. There is a clear tendency towards further reduction in trauma in the surgical access. The incision will become smaller and the number of ports will be further reduced, with the aim of ultimately having just one port (monoport surgery) or even via natural access routes (scarless surgery). Among others, improved visualization including, e.g. autostereoscopy, digital image processing and intelligent support systems, which are able to assist in a cooperative way, will enable these goals to be achieved.

NOTES in Europe: summary of the working group reports of the 2012 EURO-NOTES meeting

The sixth EURO-NOTES workshop (4 - 6 October 2012, Prague, Czech Republic) focused on enabling intensive scientific dialogue and interaction between surgeons, gastroenterologists, and engineers/industry representatives and discussion of the state of the practice and development of natural orifice transluminal endoscopic surgery (NOTES) in Europe. In accordance with previous meetings, five working groups were formed. In 2012, emphasis was put on specific indications for NOTES and interventional endoscopy. Each group was assigned an important indication related to ongoing research in NOTES and interventional endoscopy: cholecystectomy and appendectomy, therapy of colorectal diseases, therapy of adenocarcinoma and neoplasia in the upper gastrointestinal tract, treating obesity, and new therapeutic approaches for achalasia. This review summarizes consensus statements of the working groups.

Solo-surgical laparoscopic cholecystectomy with a joystick-guided camera device: a case-control study

BACKGROUND

This study aimed to evaluate the implementation of a joystick-controlled camera holder (Soloassist; Actormed, Barbing, Germany) in laparoscopic cholecystectomy as so-called solo-surgery compared with the standard operation.

METHODS

Of the 123 patients included in this study, 63 underwent laparoscopic cholecystectomy using the Soloassist system and were compared with 60 patients who underwent laparoscopic cholecystectomy with human assistance. The two groups did not differ significantly in terms of age, sex, body mass index, or American Society of Anesthesiology classification. The surgeons were divided into those highly experienced and those experienced with the new camera holder. The operation times were measured, including setup and dismantling of the system. The assessment also included complications, postoperative hospital stay, measurement of human resources in terms of personnel/minutes/operation, and subjective evaluation of the camera-guiding device by the surgeons.

RESULTS

The hospital stay and operation-related complications were not enhanced in the Soloassist group. The differences in core operation time (p = 0.008) and total operating time (p = 0.001) significantly favored the human assistant. Whereas the absolute duration of surgery was longer, the relative operating time (in personnel/minutes/operation) was significantly shorter (p < 0.001). In 4.8 % of the cases, the operation could not be performed completely with the camera-holding device. Clinically relevant postoperative complications did not occur. The experience of the surgeons did not differ significantly. The subjective evaluation regarding handling, image quality, effort, and satisfaction demonstrated high acceptance of the Soloassist system.

CONCLUSIONS

The camera-guiding device can be implemented without increased complications. The Soloassist system is safe and can be operated even by colleagues without system experience. All the surgeons rated their satisfaction with the system as very good to excellent. Although the operating times were longer than with the standard camera guidance, the absolute overall staff time was reduced.

Real-time instrument detection in minimally invasive surgery using radiofrequency identification technology

BACKGROUND

A key part of surgical workflow recording is recognition of the instrument in use. We present a radiofrequency identification (RFID)-based approach for real-time tracking of laparoscopic instruments.

METHODS

The system consists of RFID-tagged instruments and an antenna unit positioned on the Mayo stand. For reliability analysis, RFID tracking data were compared with the assessment of the perioperative video data of instrument changes (the reference standard for instrument application detection) in 10 laparoscopic cholecystectomies. When the tagged instrument was on the Mayo stand, it was referred to as "not in use." Once it was handed to the surgeon, it was considered to be "in use." Temporal miscounts (incorrect number of instruments "in use") were analyzed. The surgeons and scrub nurses completed a questionnaire after each operation for individual system evaluation.

RESULTS

A total of 110 distinct instrument applications ("in use" versus "not in use") were eligible for analysis. No RFID tag failure occurred. The RFID detection rates were consistent with the period of effective instrument application. The delay in instrument detection was 4.2 ± 1.7 s. The highest percentage of temporal miscounts occurred during phases with continuous application of coagulation current. Surgeons generally rated the system better than the scrub nurses (P = 0.54).

CONCLUSIONS

The feasibility of RFID-based real-time instrument detection was successfully proved in our study, with reliable detection results during laparoscopic cholecystectomy. Thus, RFID technology has the potential to be a valuable additional tool for surgical workflow recognition that could enable a situation dependent assistance of the surgeon in the future.

EndoResect study: endoscopic full-thickness resection of gastric subepithelial tumors

BACKGROUND AND STUDY AIMS

Endoscopic resection of gastric subepithelial tumors (SETs) carries a high risk of perforation. New techniques such as use of the over-the-scope clip (OTSC) may enable secure endoscopic closure of perforations. We aimed to evaluate the feasibility of endoscopic resection of small gastric SETs using a grasp-and-snare technique followed by OTSC closure of the gastric wall if necessary.

PATIENTS AND METHODS

In this prospective study 20 consecutive patients who presented with gastric SETs ≤ 3 cm were enrolled. Endoscopic resection was performed using a double-channel endoscope, a tissue anchor and a monofilament snare. If perforation occurred, the aim was to achieve complete closure with a tissue twin grasper and the OTSC. Procedures were performed under laparoscopic control using a 5-mm optic, which was introduced via a single 5-mm trocar through the umbilicus. All patients were followed up for 3 months after the procedure.

RESULTS

In 6 /20 patients a pure endoscopic approach was impossible and a switch to laparoscopic wedge resection was necessary (large tumor size in 2 /6 patients; mainly extraluminal growth in 4 /6 patients). Solely endoscopic resection was successfully performed in the remaining 14 patients. Amongst these, laparoscopic control was impossible in two cases. Perforation occurred in 6 /14 patients but gastric closure with the OTSC was performed successfully in all these cases. No complications occurred and follow-up was unremarkable.

CONCLUSION

Endoscopic snare resection enables safe treatment of small gastric SETs (diameter ≤ 3 cm) and seems faster and easier to perform than other endoscopic resection techniques, such as endoscopic submucosal dissection (ESD) or submucosal tunneling. Perforations occurring after full-thickness resection can be adequately managed by OTSC closure. Solely endoscopic resection without laparoscopic control seems possible in selected patients with tumors known to have purely intraluminal growth.

Endoscopic horizon stabilization in natural orifice translumenal endoscopic surgery: a randomized controlled trial

BACKGROUND

Spatial orientation in natural orifice translumenal endoscopic surgery (NOTES) has been identified as a potential barrier to clinical application. We aim to evaluate a triaxial inertial sensor and software that automatically corrects any movements on the roll axis of the flexible endoscope, allowing for stabilization of the image horizon during NOTES operations in a randomized controlled trial.

METHODS

A total of 18 participants (11 surgeons/7 gastroenterologists) performed a transgastric task in the ELITE simulator, which included navigation to the appendix and gallbladder, diathermy of the appendix base and gallbladder fossa, and clipping of the cystic duct using a single-channel gastroscope. Each participant performed the task twice with randomization to horizon stabilization occurring at the second attempt. The primary end point was change in overall performance (time taken and errors made) between the first and second attempt, and secondary end points were absolute performances in the second attempt and subjective evaluation.

RESULTS

Without horizon stabilization, there was a median improvement of 42.4% in time taken and 38% in number of errors made from the first to the second attempt; however, with the software turned on, there was a statistically significant deterioration of 4.9% (P = .038) in time taken and an increase in errors made of 183% (P = ns).

CONCLUSIONS

Although the software corrects the view to that preferred during surgery, the endoscopic control mechanism as well as the exit point of the instrument are altered in this process, leading to a deterioration of overall performance. Potential solutions include deploying intermittent horizon stabilization or using a robotic interface to achieve fully aligned perceptual-motor control.

[Diagnosis of oesophageal reflux by PH, impedance, and bilirubin measurement: recommendations of the German Society of Neurogastroenterology and of the working group for neurogastroenterology of the German Society for Digestive and Metabolic Diseases]

The current recommendations on indications, technical performance, and interpretation of diagnostic techniques for oesophageal reflux update the German recommandations about 24 hour pH measurement of 2003. The recommendations encompass conventional pH measurement, wireless pH measurement, pH and impedance measurements, and bilirubin measurement (duodenogastro-oesophageal reflux).