D Wilhelm

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.

Natural orifice transluminal endoscopic surgery: cardiopulmonary safety of transesophageal mediastinoscopy

BACKGROUND AND STUDY AIMS Physiological reactions during natural orifice transluminal endoscopic surgery (NOTES) mediastinoscopy may lead to cardiorespiratory depression. The aim of the current study was to assess cardiopulmonary changes during transesophageal mediastinoscopy in an acute porcine model. METHODS Transesophageal mediastinoscopy was performed under general anesthesia in eight female pigs with a bodyweight of 39 +/- 6 kg. Mediastinal access was achieved via a submucosal tunnel. The cardiac index and global end-diastolic volume index (reflecting preload) were measured every 3 minutes by transpulmonary thermodilution. The following parameters were also recorded: mediastinal pressure, heart rate, mean arterial pressure, systemic vascular resistance index (SVRI; reflecting afterload), peak inspiratory pressure, pH, pCO (2), and pO (2). RESULTS In three animals, small tears in the parietal pleura resulted in tension pneumothoraces. The associated cardioplumonary deterioration was fatal in one pig. The other two pigs recovered after decompression with a chest tube. In the remaining five animals there were only mild hemodynamic and respiratory changes during mediastinoscopy. There was a significant ( P = 0.005) but minor transient fall in cardiac index, which correlated with a small rise in SVRI (r = - 0.857, P < 0.001). In the pigs with uncomplicated mediastinoscopy, on-demand insufflation via the endoscope resulted in median mediastinal pressures of 4.5 mm Hg (range 2.3 - 10.2 mm Hg). Overall, mediastinal and thoracic structures could be identified without difficulty via the transesophageal approach. CONCLUSIONS NOTES mediastinoscopy carries a substantial risk of inadvertent development of a pneumothorax. Otherwise, it leads to negligible hemodynamic and pulmonary changes. In conclusion, close monitoring for the presence of a pneumothorax during NOTES mediastinoscopy appears to be mandatory.

Endoskopisches Operieren über natürliche Körperöffnungen (NOTES) in Deutschland: Zusammenfassung der Arbeitsgruppensitzungen der „D-NOTES 2009”

The D-NOTES-group met in June 2009 for an evaluation of ongoing preclinical and clinical activities in natural orifice endoscopic surgery and the further coordination of research in Germany. Different working groups with various topics were formed. Consensus statements among various participants with different scientific and medical background were initiated. In summary, important topics were handled such as the correct handling of bacterial contamination and related complications, the question of the ideal entry point and a secure closure, interdisciplinary cooperation, and matters related to training and education. Furthermore, participants agreed on terminological basics. A to-do-list for medical engineering was formulated.

Natural-orifice transluminal endoscopic surgery: low-pressure pneumoperitoneum is sufficient and is associated with an improved cardiopulmonary response (PressurePig Study).

BACKGROUND AND AIMS The aim of this randomized trial in the acute porcine model was to compare the quality of transgastric peritoneoscopy with the use of low-pressure versus standard-pressure pneumoperitoneum and to evaluate the respective associated cardiopulmonary changes. METHODS For transgastric peritoneoscopy, carbon dioxide was insufflated via the endoscope for a constant intraperitoneal pressure of 6 mmHg or 12 mmHg in 9 pigs each. The quality of transgastric peritoneoscopy was rated on a visual analog scale (0 mm, min.; 100 mm, max.) by the endoscopist, who was blinded to the intraperitoneal pressure. The cardiac index and global end-diastolic volume index (GEDVI, reflecting preload) were measured every 3 minutes by transpulmonary thermodilution. The following were also recorded: heart rate, mean arterial pressure (MAP), systemic vascular resistance index (SVRI, reflecting afterload), peak inspiratory pressure (PIP), pH, PCO (2), and PO (2). RESULTS The quality of transgastric peritoneoscopy with the use of low-pressure pneumoperitoneum was not inferior to that obtained using standard-pressure pneumoperitoneum (87.0 mm vs. 87.3 mm; P<0.05). In both groups we observed a statistically significant rise in MAP and SVRI. The increase in SVRI was less pronounced during low-pressure peritoneum ( P=0.042), indicating a reduced stress response in comparison to standard-pressure peritoneum. There were no relevant differences between the groups in relation to cardiac index, GEDVI, and heart rate. An intra-abdominal pressure of 6 mmHg also led to better oxygenation ( P=0.031 for difference in PO (2) between the two groups) due to lower peak inspiratory pressure ( P<0.001 for difference). There were only slight differences between the groups with regard to pH and PCO (2). CONCLUSIONS Pneumoperitoneum of 12-16 mmHg is used for standard laparoscopy. For NOTES, low-pressure pneumoperitoneum is sufficient and is associated with an improved cardiopulmonary response compared to standard-pressure pneumoperitoneum.

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.

Laparoscopic Cholecystectomy - a Standardized Routine Laparoscopic Procedure: Is it Possible to Predict the Duration of an Operation?

In order to improve operating room efficiency, it is desirable to predict the duration of scheduled surgeries as precisely as possible. The reliability of existing predicting models is less than satisfactory. This study presents an algorithm to estimate the operating time for laparoscopic cholecystectomy, based on historical data of 312 patients, taking into account clinical parameters, diagnostic imaging, and surgeons experience. The algorithms accuracy was evaluated in a group of 45 patients by prospectively predicting their operating times. It was shown that increased information significantly reduced prediction error. The prediction error of our algorithm was estimated to be 17.5 minutes (95%CI: 16.5 to 18.8 minutes), whereas that of the univariable random effect model (using solely surgeons experience as the explanation factor) was 21.6 minutes (95%CI: 20.3 to 23.1 minutes).

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.

Transsigmoid access for NOTES

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.ZusammenfassungDer transsigmoidale Zugang für NOTES („natural orifice transluminal endoscopic surgery“) -Operationen ist nicht auf ein Geschlecht beschränkt und weist einen gut kontrollierbaren Entrierungspunkt auf. Über ihn können praktisch alle intraabdominalen Regionen erreicht werden. Andererseits gilt er als besonders kontaminationsgefährdet und Insuffizienzen des Eingangspunktes sind wesentlich komplikativer als bei konkurrierenden Zugängen. Bisher liegen nur wenige Daten über den Einsatz im Tierversuch vor, wobei unterschiedliche chirurgische Techniken angegeben wurden. Für einen erfolgreichen Einsatz sind wohl spezialisierte Instrumentarien erforderlich, die auf dem Prinzip der transanalen endoskopischen Operation (TEO) basieren, und spezialisierte Instrumentenschleusen (Trokare/„overtubes“) sowie den Einsatz des transrektalen Ultraschalls umfassen.AbstractTranssigmoidal 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.

NOTES über den transsigmoidalen Zugang@@@Transsigmoid access for NOTES

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.ZusammenfassungDer transsigmoidale Zugang für NOTES („natural orifice transluminal endoscopic surgery“) -Operationen ist nicht auf ein Geschlecht beschränkt und weist einen gut kontrollierbaren Entrierungspunkt auf. Über ihn können praktisch alle intraabdominalen Regionen erreicht werden. Andererseits gilt er als besonders kontaminationsgefährdet und Insuffizienzen des Eingangspunktes sind wesentlich komplikativer als bei konkurrierenden Zugängen. Bisher liegen nur wenige Daten über den Einsatz im Tierversuch vor, wobei unterschiedliche chirurgische Techniken angegeben wurden. Für einen erfolgreichen Einsatz sind wohl spezialisierte Instrumentarien erforderlich, die auf dem Prinzip der transanalen endoskopischen Operation (TEO) basieren, und spezialisierte Instrumentenschleusen (Trokare/„overtubes“) sowie den Einsatz des transrektalen Ultraschalls umfassen.AbstractTranssigmoidal 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.

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

ZusammenfassungIm vergangenen Jahrzehnt wurden erstmals Robotiksysteme in fast allen operativen medizinischen Disziplinen evaluiert. Von wenigen Ausnahmen abgesehen (radikale Prostatektomie) haben mechatronische Supportsysteme in keinem Einsatzbereich einen echten therapeutischen Durchbruch erzielen können. Gerätesysteme der zweiten Generation mit besserer Integration von Komplementärsystemen (präoperative Therapieplanung, intraoperative Diagnostik, Navigation und so weiter) und verbesserter Funktionalität stehen heute vor der klinischen Einführung und versprechen eine bessere Nutzbarmachung der spezifischen Vorteile von Robotiksystemen in der klinischen Praxis. Für neuere Entwicklungen in der operativen Therapie („narbenloses Operieren“) stellt die Robotik eine Schlüsseltechnologie dar.AbstractDuring 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.ZusammenfassungIm vergangenen Jahrzehnt wurden erstmals Robotiksysteme in fast allen operativen medizinischen Disziplinen evaluiert. Von wenigen Ausnahmen abgesehen (radikale Prostatektomie) haben mechatronische Supportsysteme in keinem Einsatzbereich einen echten therapeutischen Durchbruch erzielen können. Gerätesysteme der zweiten Generation mit besserer Integration von Komplementärsystemen (präoperative Therapieplanung, intraoperative Diagnostik, Navigation und so weiter) und verbesserter Funktionalität stehen heute vor der klinischen Einführung und versprechen eine bessere Nutzbarmachung der spezifischen Vorteile von Robotiksystemen in der klinischen Praxis. Für neuere Entwicklungen in der operativen Therapie („narbenloses Operieren“) stellt die Robotik eine Schlüsseltechnologie dar.AbstractDuring 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.