PLAFOKON: a new concept for a patient-individual and intervention-specific flexible surgical platform.

BACKGROUND: Research in the field of surgery is mainly driven by aiming for trauma reduction as well as for personalized treatment concepts. Beyond laparoscopy, other proposed approaches for further reduction of the therapeutic trauma have failed to achieve clinical translation, with few notable exceptions. We believe that this is mainly due to a lack of flexibility and high associated costs. We aimed at addressing these issues by developing a novel minimally invasive operating platform and a preoperative design workflow for patient-individual adaptation and cost-effective rapid manufacturing of surgical manipulators. In this article, we report on the first in-vitro cholecystectomy performed with our operating platform. METHODS: The single-port overtube (SPOT) is a snake-like surgical manipulator for minimally invasive interventions. The system layout is highly flexible and can be adapted in design and dimensions for different kinds of surgery, based on patient- and disease-specific parameters. For collecting and analyzing this data, we developed a graphical user interface, which assists clinicians during the preoperative planning phase. Other major components of our operating platform include an instrument management system and a non-sterile user interface. For the trial surgery, we used a validated phantom which was further equipped with a porcine liver including the gallbladder. RESULTS: Following our envisioned preoperative design workflow, a suitable geometry of the surgical manipulator was determined for our trial surgery and rapidly manufactured by means of 3D printing. With this setup, we successfully performed a first in-vitro cholecystectomy, which was completed in 78 min. CONCLUSIONS: By conducting the trial surgery, we demonstrated the effectiveness of our PLAFOKON operating platform. While some aspects - especially regarding usability and ergonomics - can be further optimized, the overall performance of the system is highly promising, with sufficient flexibility and strength for conducting the necessary tissue manipulations.

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.

A new 3D-printed overtube system for endoscopic submucosal dissection: first results of a randomized study in a porcine model.

BACKGROUND AND STUDY AIM: Endoscopic therapy of early malignant alterations can be difficult and cumbersome. Our research study group took advantage of new methods for rapid prototyping (i. e. 3D printing) to design and test an overtube system with two manipulator arms at the tip. Both arms can be steered independently from each other by a dedicated user platform. METHODS: This animal study involved a randomized evaluation of the new overtube device for endoscopic submucosal dissection (ESD) compared with a conventionally performed ESD. In total, 12 ESDs in six pigs were performed. Six ESDs were performed in the stomach and six in the colon. Size (in cm(2)) of resected specimens, the time needed to perform endoscopic resection, and adverse events were assessed. RESULTS: The overtube-assisted ESD was faster and therefore more effective than the conventional ESD technique (0.45 ±â€Š0.24 cm(2)/min vs. 0.22 ±â€Š0.11 cm(2)/min; P = 0.029). Only one adverse effect was recorded in the conventional group.  CONCLUSIONS: The overtube-assisted ESD was feasible in an animal model. ESD can be performed more quickly and potentially more effectively with the newly designed overtube device compared with the conventional ESD technique.

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.

Evaluation of long-term stability of monolithic 3D-printed robotic manipulator structures for minimally invasive surgery.

PURPOSE: In the era of patient-centered medicine, clinical procedures, tools and instruments should be individually adapted to the patient. In this context, the presented 3D-printed Single-Port Overtube Manipulator System follows the aims to provide patient- and task-specific disposable manipulators for minimally invasive surgery. In a first experiment, the robustness of the monolithic flexure hinge structures in use as robotic manipulators will be investigated. METHODS: Customizable monolithic manipulator structures designed by means of an automated design process and manufactured with selective laser sintering were investigated with regard to long-term stability in an endurance test. Therefore, a bare manipulator arm, an arm equipped with a standard instrument and finally loaded with an additional load of 0.5 N were evaluated by continuously following a trajectory within the workspace of the manipulator arms over a period of 90 min. RESULTS: The unloaded manipulator as well as the manipulator arm equipped with a standard instrument showed a sufficient reproducibility (deviation of 1.5 mm and 2.5 mm, respectively, on average) with regard to an application as telemanipulated master-slave surgical robotic system. The 3D-printed manipulators showed no damage and maintained integrity after the experiment. CONCLUSION: It has been shown that 3D-printed manipulators in principle are suitable for use as disposable surgical manipulator systems and offer a long-term stability over at least 90 min. The developed manipulator design shows great potential for the production of patient-, task- and user-specific robot systems. However, the manipulator geometries as well as the control strategies still show room for improvements.

Improved endoscopic resection of large flat lesions and early cancers using an external additional working channel (AWC): a case series.

Background En-bloc resection of large, flat lesions or early stages of cancer is challenging. No bimanual tasks are possible using standard endoscopes. Dual-channel endoscopes are not available everywhere and have a small distance between the channels. Patients and methods A new external additional working channel (AWC) (Ovesco, Tuebingen, Germany) was designed and developed potentially enabling bimanual tasks. Fixed to the tip of a standard gastroscope or pediatric colonoscope, a second endoscopic tool can be inserted through the AWC and used for tissue retraction during endoscopic resection. Results In the upper and lower gastrointestinal tract, endoscopic mucosal resection (EMR) with a modified grasp-and-snare technique and endoscopic submucosal dissection (ESD) were performed successfully using the AWC in eight patients. Complications were acute arterial bleeding post-EMR in two cases treated by endoscopic clipping. Conclusions We conclude that a newly developed external additional working channel (AWC) enables endoscopic resection of large lesions in the upper and lower gastrointestinal tract. Potential benefits are its suitability for EMR and ESD, no need for a dual-channel endoscope and an adjustable distance of working channels.