Safe sigmoid access for natural orifice transluminal endoscopic surgery (NOTES).

One of the main challenges in transluminal surgery is sterile and safe access. For many interventions, a transanal approach would be ideal but it is considered too risky because of contamination and the danger of secondary leakage. A new safe and sterile transanal access was developed, combining four basic principles: (i) the creation of a decontaminating hydroperitoneum, (ii) the use of an overtube, (iii) defining the entry point with ultrasound and (iv) dedicated closure technique. Applicability and reliability was first proven in extensive animal experiments. Feasibility of the concept in humans was subsequently demonstrated in cadavers.

Training of a standardized natural orifice transluminal endoscopic surgery cholecystectomy using an ex vivo training unit.

BACKGROUND AND STUDY AIMS: The endoscopic-laparoscopic interdisciplinary training entity (ELITE) is one of the first training models for the training of natural orifice transluminal endoscopic surgery (NOTES) and conventional laparoscopic and endoscopic skills. The current study was designed to assess whether the effect of surgical simulation with an ex vivo training unit is relevant to surgical practice in the operating room and who, in particular, might benefit from this training. PATIENTS AND METHODS: A group of 30 participants (gastroenterologists, laparoscopists, and novices) performed a standardized NOTES cholecystectomy via a trans-sigmoidal approach. Fifteen participants performed the cholecystectomy following training with ELITE and 15 participants performed the procedures without previous training. The parameters studied were task times, quality and safety of the surgical procedure, and subjective evaluation of the ELITE trainer as a teaching model. RESULTS: During the training courses all participants showed a significant learning curve, with a total time needed on the first pass of 32 minutes vs. 18 minutes for the fourth pass ( P < 0.001). For the cholecystectomy in the pig model, participants with prior training needed less time to complete the procedure than participants without training. In the group without training, more complications/difficulties occurred than in the group with prior training (16 vs. 8). The video analyses by two independent NOTES experts showed an inter-rater validity of 1.0. Subjective evaluation showed that participants considered ELITE to be a suitable and recommendable simulator for NOTES. CONCLUSIONS: The ELITE model is suitable for training in the NOTES cholecystectomy procedure. This type of simulator training leads to fewer intraoperative complications.

NOTES for the cardia: antireflux therapy via transluminal access.

BACKGROUND AND STUDY AIMS: The current standard for surgical antireflux therapy is laparoscopic Nissen fundoplication, but natural orifice transluminal endoscopic surgery (NOTES) enables even less invasive access to the peritoneal cavity. We therefore aimed to evaluate a NOTES approach to antireflux therapy. PATIENTS AND METHODS: An animal study including 24 pigs (16 nonsurvival and eight survival). After the peritoneal cavity had been accessed via the rectosigmoid, the gastroesophageal junction (GEJ) was laid open using conventional endoscopic instruments. Thereafter, a transcutaneously introduced hook was used for tunneling and lifting of the distal esophagus. Finally, an antireflux ring was placed around the cardia. Animals were observed over 10 days in the survival series. Correct application of the prosthesis, adverse events as a result of the procedure, and bacterial contamination were evaluated by autopsy. RESULTS: The esophagogastric junction was strengthened by applying the ring prosthesis in 22 of 24 animals. Four bleeding episodes were observed, three of which were handled endoscopically. Correct placement of the prosthesis was accomplished in 21 of 22 animals. In the survival series, 1 pig died after transhiatal herniation of the stomach, and 1 pig suffered from peritonitis due to intraoperative contamination. In 7 of the 8 survival animals, no bacterial growth was noted by smear culture. The intervention had to be performed as a hybrid NOTES procedure in all cases. CONCLUSION: Exposure of the GEJ and placement of an antireflux prosthesis via a hybrid NOTES procedure is feasible, despite some complications. This approach may be considered as a basis for optimization and further development of pure NOTES antireflux procedures.

[Efficiency, risks, and advantages of using robotic support systems in interventional medicine]. / Leistungsfähigkeit, Risiken und Vorteile des Einsatzes der Robotik in medizinisch-operativen Disziplinen.

During the past decade, robotic systems were evaluated for the first time in practically all surgical disciplines. With only a few exceptions (radical prostatectomy), mechatronic systems did not achieve a breakthrough in any field of application. Second generation robotic devices with better integration of complementary technologies (preoperative therapy planning, intraoperative diagnostic work-up, navigation, etc.) and augmented functionality are now ready to be introduced into clinical practice. It is hoped that the specific advantages of robotics will result in increased use compared to previous systems. Robotics is a key technology if new surgical strategies ("scarless surgery") are to succeed.

[Transsigmoid access for NOTES]. / NOTES über den transsigmoidalen Zugang.

Transsigmoidal access for NOTES operations is not limited by gender and offers an outstanding controllability of the entry point. Practically all anatomical regions of the abdomen are easily accessible. However, it is particularly prone to contamination and leakage and insufficiency of the access mean that it is far more prone to complications than using alternative access points. Currently, only few data are available on the results of animal experiments and differing technical approaches have been employed. Dedicated surgical instruments are required which should be modified according to the well proven transanal endoscopic microsurgery (TEM) set of instruments. In addition, specialized instrumentation (overtubes/trocars) and the use of transanal ultrasound seem to be recommendable.

Evaluation of mist production and tissue dissection efficiency using different types of ultrasound shears.

BACKGROUND: Ultrasound shears often are applied in minimally invasive surgery because they facilitate fast and secure tissue dissection, thereby reducing operative time. Although the technical principle underlying all the shears is almost identical, considerable differences exist between specific instruments. However, production of disturbing mist should be avoided. METHODS: To obtain quantitative measurements regarding mist production, a novel hermetically sealed test system was developed. Tissue dissection efficiency was evaluated by means of a standardized cutting test. The dissection time and the numbers of cuttings were recorded. In this study, four different ultrasound dissectors from three manufacturers were assessed. One manufacturer provided two instruments: a conventional instrument and an improved version, which was designed particularly to reduce mist emission. RESULTS: The fastest ultrasound dissector emitted the highest quantity of disturbing mist. However, improved dissection efficiency does not linearly correlate with mist production. This clearly could be shown for the improved "less mist production instrument," which turned out to work faster than the comparable standard dissector but produced significantly less mist. CONCLUSION: Ultrasonic shears are effective for bloodless tissue dissection but may impede surgical proceeding by mist production. The findings of this study demonstrate that emission of mist can be reduced not only by lowering the dissection power, resulting in a prolonged dissection time, but also by modifying the technical design of an instrument. Further development of ultrasonic cutting devices therefore should account for the desired results.

The "ELITE" model: construct validation of a new training system for natural orifice transluminal endoscopic surgery (NOTES).

BACKGROUND AND STUDY AIMS: The ELITE (endoscopic-laparoscopic interdisciplinary training entity) trainer is a new ex vivo model designed to train conventional laparoscopic and endoscopic skills and to perform hybrid interventions. The aim of the present study was to assess its usefulness for natural orifice transluminal endoscopic surgery (NOTES) procedures. MATERIALS AND METHODS: A group of 30 participants (eight gastroenterologists, 22 surgeons) ranging from novices to experts completed the following tasks. Via a trans-sigmoidal approach, anchor points in each quadrant in the abdominal cavity had to be reached. Each participant performed five consecutive courses. The time needed to perform the experiment was evaluated. In a second step to assess advanced skill for NOTES in an external face validation, 20 randomly selected individuals performed a cholecystectomy via the same trans-sigmoidal access. RESULTS: All participants passed a significant learning curve during the assessment (total time needed: 473.1 +/- 178.5 seconds for first pass vs. 321.9 +/- 182.0 seconds for fifth pass; P = 0.02, Wilcoxon test). There were 15 novices and 15 endoscopy experts. Significant differences were observed for the total time required to perform the respective procedures between these two groups (first pass: 394.3 +/- 176.6 seconds for experts vs. 531.9 +/- 166.7 seconds for novices; P = 0.040, Mann-Whitney test). Furthermore, NOTES cholecystectomies could successfully be simulated. Participants considered the ELITE to represent a useful simulator for NOTES. CONCLUSION: The newly developed ELITE trainer is a suitable tool to train NOTES techniques. Experts could reliably be distinguished from novices and a significant progress by training could be demonstrated.

Instrumentation and surgical technique for an innovative safe sigmoid approach for NOTES.

A set of new instruments was designed to establish an access to the abdominal cavity for NOTES via the rectosigmoid. It comprehends a metal overtube which is positioned using a modified TEM device. The entry point is targeted by transrectal ultrasound and secured by a purse-string suture. Closure is achieved by means of a linear stapler application. The applicability of the system could already be confirmed in animal survival studies.

An innovative, safe and sterile sigmoid access (ISSA) for NOTES.

BACKGROUND AND STUDY AIMS: The use of a transcolonic approach for natural orifice transluminal endoscopic surgery (NOTES) offers relevant advantages compared with a transgastric procedure. However both techniques are still limited by specific shortcomings that need to be resolved before the transluminal approach can be translated to human applications. In this article we describe an innovative method for a transcolonic procedure, which might represent the next step forward in NOTES. PATIENTS AND METHODS: In three acute and five survival porcine models we evaluated a specially designed guide tube, which is inserted via a transcolonic approach into the abdominal cavity after intraperitoneal instillation of a decontamination solution. After endoscopic evaluation of the abdomen the closure of the entry site was performed surgically. Main parameters obtained in the study were the feasibility and safety of the approach, the bacterial contamination due to the transcolonic procedure, and the safe closure of the entry site. Animals in the survival model were euthanized 10 days after the procedure. RESULTS: The transcolonic approach took place without complications. There was no bleeding or laceration of adjacent organs. The surgical closure guaranteed a leak-proof closure of the entry site. All pigs in the survival model showed an excellent postinterventional course. At necropsy, the colonic incision sites were completely closed and appeared well healed. No abscesses or any sign of inflammation could be identified. CONCLUSIONS: The transcolonic approach using an innovative guide tube is feasible and safe. The technique described offers mentionable advantages and therefore reduces the known shortcomings of NOTES. However, further studies are needed to approve our results of an initial evaluation.