Development, standardization, and evaluation of NOTES cholecystectomy using a transsigmoid approach in the porcine model: an acute feasibility study

BACKGROUND

Transluminal cholecystectomy is feasible. However, the procedure is time consuming, difficult, and poorly standardized so far. In the present study we therefore aimed to further evaluate and optimize a transsigmoid approach for cholecystectomy with minimal transabdominal assistance in the porcine model.

METHODS

After a pilot series of 6 pigs, NOTES (natural-orifice transluminal endoscopic surgery) cholecystectomy was performed in a standardized manner in another 12 pigs. A transsigmoid approach was applied via a specially designed trocar (ISSA) with a double-channel gastroscope advanced into the peritoneal cavity. After identification of the infundibulum, the cystic duct and artery were closed by application of hemostasis clips. After dissection of these structures, the gallbladder was separated from the liver by electrocautery following injection of isotonic saline solution. A grasper introduced through a modified Veress needle (initially used for establishing the hydroperitoneum) and an additional transcutaneous stay suture were used to ease preparation of the gallbladder.

RESULTS

Transluminal cholecystectomy was successfully performed in all animals. No serious acute complications occurred; minor bleeding in 4 out of 12 cases (1 cystic artery and 3 liver parenchyma) was successfully handled by electrocautery. Clip application to close the cystic duct and artery resulted in complete sealing. Standardization of the procedure was associated with a significant decrease in total operating time (113.3 +/- 31.8 minutes for the first 6 pigs and 73.6 +/- 17.2 minutes for the last 6 pigs).

CONCLUSIONS

In pigs with a healthy gallbladder, our standardized technique of transsigmoid cholecystectomy could be performed relatively fast with acceptable complication rates at this level of evolution, as shown in these acute experiments.

Evaluation of M-AID®, a first aid application for mobile phones

BACKGROUND

When performed effectively, cardiopulmonary resuscitation (CPR) by bystanders reduces mortality due to sudden cardiac arrest. Telemedicine applications offer a means by which bystanders can get specific instructions for handling the emergency situation. M-AID, a first aid application for mobile phones, uses an intelligent algorithm of 'yes' or 'no' questions to judge the ongoing situation and give the user detailed instructions. The aim of this study was to evaluate the benefit of this mobile phone application in a scenario of sudden cardiac arrest.

METHODS

One hundred and nineteen volunteers were assigned at random either to the test or the control group. All participants were confronted with the same scenario of acute coronary syndrome leading to cardiac arrest. The participants were either equipped with a mobile phone running the software (test group) or had to handle the situation without support (control group). The participants received a certain amount of credits for each action taken according to a pre-defined protocol and these credits were added to a score and compared between the groups. Participants were divided into subgroups according to their medical and technical experience.

RESULTS

The test group generally achieved a slightly higher average score that was not statistically significant (21.11 versus 19.97; p=0.302). In contrast, the performance of the individuals in the control group was significantly faster (2.41 min versus 4.24 min; p<0.001). Use of the mobile phone software did not enhance the chance of survival. Subgroup analysis showed that experienced mobile phone users performed significantly better than non-experienced individuals, but not as well as participants with advanced first aid knowledge.

CONCLUSIONS

Experience in the use of mobile phones is a prerequisite for the efficient use of the tested M-AID version. This application cannot replace skills acquisition by practical training. In a subgroup with experience in mobile phone use and basic knowledge in CPR, the device improved performance of CPR.

[Radiological diagnostics for iatrogenic retained foreign bodies after surgery]

Retention of surgical sponges is rare. They cause either an aseptic reaction without significant symptoms or an exudative reaction which results in early but non-specific symptoms. Even if there are no studies which compare the diagnostic accuracy of the different imaging modalities, CT seems to be the most promising tool to diagnose foreign bodies. However, apart from radio-paque markers there are no specific signs for the existence of surgical sponges in CT. Therefore, an experienced radiologist is needed to differentiate foreign bodies from morphologically quite similar differential diagnoses such as abscess and haematoma.

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.

Der laparoskopische Ultraschall

Laparoscopic ultrasound exploration has significantly augmented the range of minimally invasive surgery. In particular it is essential for 3D exploration of the abdomen for staging. Beyond its diagnostic, purposes laparoscopic ultrasound is gaining importance for intraoperative therapeutic support, e. g. imaging of the biliary tree during laparoscopic surgery of the bile duct and for navigation during radio-frequency ablative or resective interventions on the liver and other parenchymatous organs. Compared to other imaging procedures, sonography has still the highest potential for further development. The most progress can be expected in navigated ultrasound.

Transgastric in vivo histology in the peritoneal cavity using miniprobe-based confocal fluorescence microscopy in an acute porcine model

BACKGROUND AND STUDY AIMS

Natural orifice transluminal endoscopic surgery (NOTES) is an emerging technology. Apart from its therapeutic implications, this type of access to the peritoneal cavity might also be useful for targeted in vivo histological investigation by means of confocal fluorescence microscopy. In this study we therefore aimed to assess the feasibility of miniprobe-based confocal fluorescence microscopy during transgastric endoscopy in an acute porcine model.

MATERIALS AND METHODS

Transgastric in vivo histology was performed in five pigs, under general anesthesia. After incision of the anterior gastric wall, a double-channel video gastroscope was advanced into the peritoneal cavity. A flexible confocal miniprobe was introduced through the instrument channel of the endoscope after intravenous injection of 10 mL of fluorescein 1% in four of the pigs and of 50 mL of fluorescein isothiocyanate-dextran 150 000 4% in the fifth pig. The tip of the miniprobe was then placed on the peritoneal layer, the liver, and the spleen for confocal laser microscopy.

RESULTS

Probes were easily attached to the peritoneal layer, the liver, and the spleen under direct visualization with the endoscope. Dynamic microscopic images of these organs were obtained with a frame rate of 12 frames per second. The flow of erythrocytes through blood vessels could be seen. The microstructural components of organs, such as lobules of the liver, were also easily identified.

CONCLUSIONS

In vivo histology in the peritoneal cavity is feasible during NOTES and this technique combines the minimally invasive approach to the intraperitoneal organs afforded by NOTES and real-time, in vivo acquisition of dynamic histological images.

[Oesophageal tumours--what does the surgeon need from the radiologist?]

Surgery is the most important therapeutic discipline for oesophageal cancers and the surgeon has specific questions for the radiologist which can require various imaging procedures. The radiological presentation is, for example, necessary for the topographic imaging of larger space occupying processes, the localization and axial spread of which are important for the surgical procedure chosen. Imaging diagnostics helps with the identification of R0 resectable patients. High resolution computed tomography (CT) of the mediastinum is used to clarify the spatial relationship between oesophageal cancer and the tracheobronchial system. This method also helps demonstrate the presence of fistulas in the tracheobronchial system or mediastinum. Using a neck or thorax CT, or a PET-CT distant metastases can be documented and a second tumour excluded. Imaging procedures gain additional significance for the evaluation of the T stage of the oesophageal tumour or the response to neoadjuvant therapy concepts, for which an earliest possible response evaluation is of great importance. Imaging procedures are also of importance in aftercare as it is sometimes possible and valuable to carry out surgery for local relapses.

Staginglaparoskopie in der Onkologie

The availability of more treatment options for gastrointestinal cancer requires precise and reliable pretherapeutic staging. Despite impressive technical progress in modern imaging procedures, this high level of staging quality is not yet warranted in all instances. Visual exploration of the abdominal cavity in extended diagnostic laparoscopy (EDL), including surgical dissection of areas which are primarily inaccessible, biopsy retrieval, and laparoscopic ultrasound, is superior in the diagnostic workup of early peritoneal carcinomatosis and (small) liver metastases. It is helpful to evaluate lymph node infliction and local resectability. In esophageal carcinoma, pretherapeutic EDL is valuable in case of advanced adenocarcinoma of the distal esophagus (AEG I according to Siewert), whereas the incidence of abdominal tumor manifestations in squamous cell carcinoma is too low to perform staging laparoscopy. In advanced gastric cancer, EDL yields relevant additional information in up to 20% of cases. If a multimodal therapeutic strategy is considered, EDL should be obligatory at least in prospective therapeutic studies. In carcinoma of the pancreas, EDL is in general not recommended by the majority of centers. Selective use (in particular in advanced cancer with a high probability of local irresectability) is gaining importance. In hepatobiliary malignancy including colorectal metastases, the high yield of additional information by EDL was confirmed in recent studies.

Endoluminal endosurgery: rivet application in flexible endoscopy

BACKGROUND

Endoluminal endoscopy could be significantly enhanced by adequate approaches to wound closure. Current solutions are basically confined to clip applications.

OBJECTIVE

A new approach to sewing in flexible endoscopy is achieved with an endoluminal rivet system. This system allows the application of several ligatures without withdrawing the rivet application device to reload. For this purpose, a pilot experimental study of the device was conducted, which obtained a tissue approximation and avoided the difficult process of knot tying.

DESIGN

Pilot experimental study.

SETTING

The rivet application was tested through a 1.8-mm working channel of the endoscope in laboratory and postmortem animal tissues. It consists of a flexible anchor at the front and a lockable bracket at the rear. Both edges of a defect of the GI wall can be aligned and compressed, thus leading to wound closure.

INTERVENTIONS

Test samples were evaluated in postmortem gastric tissue by using flexible gastroscopes. The feasibility of applying a series of rivets with 1 instrument to close transmural lacerations of the stomach was demonstrated. Further tests were performed to determine the forces to penetrate the gastric wall.

MAIN OUTCOME MEASUREMENTS

Tissue closure, rivet degradation.

RESULTS

The penetration force can be brought down to less than 0.57 N by using a magnesium tip. The sharp tip of the rivet, which could potentially lacerate healthy tissue after implantation, is degraded in the stomach within the first few hours because of rapid corrosion.

LIMITATIONS

Lack of in vivo feasibility data.

CONCLUSIONS

Endoluminal wound closure through common gastroscopes and colonoscopes is possible. Further in vivo data are required for the rivet system.

Computer simulation for ergonomic improvements in laparoscopic surgery

It is the aim of this study to reduce the stress and strain of the medical staff during laparoscopic operations, and, simultaneously, to increase the safety and efficiency of an integrated operation room (OR) by an ergonomic redesign. This was attempted by a computer simulation approach using free modelling of the OR and 3D human models (manikins). After defining ergonomically "ideal" postures, optimal solutions for key elements of an ergonomic design of the OR (position and height of the image displays, height of the OR table and the Mayo stand) could be evaluated with special regard to the different individual body size of each member of the team. These data should be useful for the development of team adapted, user friendly integrated OR suites of the future.

Recovery of Surgical Workflow Without Explicit Models

Workflow recovery is crucial for designing context-sensitive service systems in future operating rooms. Abstract knowledge about actions which are being performed is particularly valuable in the OR. This knowledge can be used for many applications such as optimizing the workflow, recovering average workflows for guiding and evaluating training surgeons, automatic report generation and ultimately for monitoring in a context aware operating room. This paper describes a novel way for automatic recovery of the surgical workflow. Our algorithms perform this task without an implicit or explicit model of the surgery. This is achieved by the synchronization of multidimensional state vectors of signals recorded in different operations of the same type. We use an enhanced version of the dynamic time warp algorithm to calculate the temporal registration. The algorithms have been tested on 17 signals of six different surgeries of the same type. The results on this dataset are very promising because the algorithms register the steps in the surgery correctly up to seconds, which is our sampling rate. Our software visualizes the temporal registration by displaying the videos of different surgeries of the same type with varying duration precisely synchronized to each other. The synchronized videos of one surgery are either slowed down or speeded up in order to show the same steps as the ones presented in the videos of the other surgery.

Electromagnetic Catheter Navigation During Bronchoscopy

BACKGROUND

Electromagnetic navigation in bronchoscopy is a novel method for assisting in the localization of peripheral lung lesions.

STUDY OBJECTIVE

To assess the usability, accuracy, and safety of electromagnetic navigation during flexible bronchoscopy in a clinical setting.

DESIGN

Prospective evaluation.

PATIENTS

Consecutive patients referred to the bronchoscopy unit for the diagnosis of peripheral infiltrates or solitary pulmonary nodules (SPNs).

METHODS

Navigation was performed using an electromagnetic tracking system with a position sensor encapsulated in the tip of a flexible catheter that was pushed through the working channel of the bronchoscope. Real-time, multiplanar reconstruction of a previously acquired CT data set provided three-dimensional views for localization of the catheter. To match the position of the sensor with the CT scan, four anatomic landmarks were used for registration. The sensor position generated in the navigation system was controlled by fluoroscopy, and the corresponding error distances were measured. This was performed with all SPNs and at two different peripheral locations of the right upper lobe (RUL).

RESULTS

Sixteen patients (10 men and 6 women; mean age, 63.7 years) were studied. Navigation prolonged bronchoscopy by 3.9 +/- 1.3 min (mean +/- SD). The navigation system identified all lesions. The position sensor achieved a direct hit in three of five SPNs. Fluoroscopy failed to recognize three SPNs (60%) and three infiltrates (38%). The mean error distances between sensor tip position and fluoroscopically verified RUL reference position were 10.4 mm (lateral position) and 12.5 mm (apical position) respectively. The mean error distances between the sensor tip and two endobronchial registration points at the end of the procedure were 4.2 mm and 5.1 mm, respectively.

CONCLUSION

Electromagnetic navigation is useful, accurate, and safe in the localization of peripheral lung lesions and may help to improve the yield of diagnostic bronchoscopic procedures.

In vivo kinematic measurement during laparoscopic cholecystectomy

BACKGROUND

Despite the rapid development of computer-assisted surgery, studies on kinematic measurement for surgical innovation are rare. This study describes a system for kinematic measurement in real operating theater environments. Six laparoscopic cholecystectomies were recorded and analyzed. In addition to a demonstration of the feasibility of the method, basis data for the development of an actuated laparoscopic camera holder are evaluated.

METHODS

The positions of four receivers were recorded by an electromagnetic motion acquisition system. Analysis of the data was performed postoperatively with matlab. Parameters such as coordinates, velocities, angles, angular velocities, workspaces in typical phases of an operation, and subareas of the coordinate ranges were computed.

RESULTS

The workspace during the operation in situ before (II) and after (V) removal of the gallbladder at the upper camera end was as follows: (X, Y, Z; given in cm): II: 65.5 . 42.7 . 27.3 (subarea 90% = 8.3. 14.0.6.3); V: 57.4.33.3.26.2, (90% = 10.3.16.5.7.9). Workspaces at the lower camera end were smaller: II: 14.8.9.7.15.4; (90% = 3.5.3.1.4.3). During these operation phases, velocities up to 82.9 cm/s were documented. Most of the measured velocities were much smaller. The camera -tilt-angles in left/right (alphax) and head/ feet (alphay) direction were as follows: alphax: -69 degrees to +69 degrees and alphay: -74 degrees to +48 degrees.

CONCLUSION

This study demonstrates the feasibility of real-time kinematic measurement in the operation environment. The information might be of future value not only as basis data for the development of camera holders, but also for further investigations on robotics, ergonomics, and simulation.

Combined endoluminal and endocavitary approaches to colonic lesions

Colonic lesions of benign or early malignant origin may be difficult to remove by colonoscopy. However, conventional surgical resection is considered as too invasive for these types of lesions suitable for local excision. The combined laparoscopic-colonoscopic excision was performed in 75 patients (males, 42; females, 33) with benign or early malignant lesions of the colorectum. Three different variations were used: laparoscopy-assisted endoscopic resection (LAER), endoscopy-assisted laparoscopic wedge resection (EAWR), and endoscopy-assisted laparoscopic transluminal resection (EATR). If these techniques were not applicable, an endoscopy-assisted laparoscopic segment resection (EASR) was performed. Conversion rate was 5.0%. Although the expenditure of combined endoscopic/laparoscopic approaches is higher, they are attractive alternatives to either laparoscopic tubular resection or open surgery.