Carsten N. Gutt

Circulatory and Respiratory Complications of Carbon Dioxide Insufflation

Background: Although providing excellent outcome results, laparoscopy also induces particular pathophysiological changes in response to pneumoperitoneum. Knowledge of the pathophysiology of a CO2 pneumoperitoneum can help minimize complications while profiting from the benefits of laparoscopic surgery without concerns about its safety. Methods: A review of articles on the pathophysiological changes and complications of carbon dioxide pneumoperitoneum as well as prevention and treatment of these complications was performed using the Medline database. Results: The main pathophysiological changes during CO2 pneumoperitoneum refer to the cardiovascular system and are mainly correlated with the amount of intra-abdominal pressure in combination with the patient’s position on the operating table. These changes are well tolerated even in older and more debilitated patients, and except for a slight increase in the incidence of cardiac arrhythmias, no other significant cardiovascular complications occur. Although there are important pulmonary pathophysiological changes, hypercarbia, hypoxemia and barotraumas, they would develop rarely since effective ventilation monitoring and techniques are applied. The alteration in splanchnic perfusion is proportional with the increase in intra-abdominal pressure and duration of pneumoperitoneum. Conclusion: A moderate-to-low intra-abdominal pressure (<12 mm Hg) can help limit the extent of the pathophysiological changes since consecutive organ dysfunctions are minimal, transient and do not influence the outcome.

Acute cholecystitis: early versus delayed cholecystectomy, a multicenter randomized trial (ACDC study, NCT00447304).

Objective:Acute cholecystitis is a common disease, and laparoscopic surgery is the standard of care. Background:Optimal timing of surgery for acute cholecystitis remains controversial: either early surgery shortly after hospital admission or delayed elective surgery after a conservative treatment with antibiotics. Methods:The ACDC (“Acute Cholecystitis—early laparoscopic surgery versus antibiotic therapy and Delayed elective Cholecystectomy”) study is a randomized, prospective, open-label, parallel group trial. Patients were randomly assigned to receive immediate surgery within 24 hours of hospital admission (group ILC) or initial antibiotic treatment, followed by delayed laparoscopic cholecystectomy at days 7 to 45 (group DLC). For infection, all patients were treated with moxifloxacin for at least 48 hours. Primary endpoint was occurrence of predefined relevant morbidity within 75 days. Secondary endpoints were as follows: (1) 75-day morbidity using a scoring system; (2) conversion rate; (3) change of antibiotic therapy; (4) mortality; (5) costs; and (6) length of hospital stay. Results:Morbidity rate was significantly lower in group ILC (304 patients) than in group DLC (314 patients): 11.8% versus 34.4%. Conversion rate to open surgery and mortality did not differ significantly between groups. Mean length of hospital stay (5.4 days vs 10.0 days; P < 0.001) and total hospital costs (&OV0556;2919 vs &OV0556;4262; P < 0.001) were significantly lower in group ILC. Conclusions:In this large, randomized trial, laparoscopic cholecystectomy within 24 hours of hospital admission was shown to be superior to the conservative approach concerning morbidity and costs. Therefore, we believe that immediate laparoscopic cholecystectomy should become therapy of choice for acute cholecystitis in operable patients. (NCT00447304)

Robot‐assisted abdominal surgery

Robotic assistance or telemanipulation is the latest technological advance in minimally invasive surgery. Its future implementation will depend on the advantages that it can provide over standard laparoscopy or open surgery.

Robot-assisted versus conventional laparoscopic fundoplication: short-term outcome of a pilot randomized controlled trial

BackgroundRobotic technology represents the latest development in minimally-invasive surgery. Nevertheless, robotic-assisted surgery seems to have specific disadvantages such as an increase in costs and prolongation of operative time. A general clinical implementation of the technique would only be justified if a relevant improvement in outcome could be demonstrated. This is also true for laparoscopic fundoplication. The present study was designed to compare robotic-assisted (RALF) and conventional laparoscopic fundoplication (CLF) with the focus on operative time, costs und perioperative outcome.MethodsForty patients with gastro-esophageal reflux disease were randomized to either RALF by use of the daVinci® Surgical System or CLF. Nissen fundoplication was the standard anti-reflux procedure. Peri-operative data such as length of operative procedure, intra-and postoperative complications, length of hospital stay, overall costs and symptomatic short-term outcome were compared.ResultsThe total operative time was shorter for RALF compared to CLF (88 vs. 102 min; p = 0.033) consisting of a longer set-up (23 vs. 20 min; p = 0.050) but a shorter effective operative time (65 vs. 82 min; p = 0.006). Intraoperative complications included one pneumothorax and two technical problems in the RALF group and two bleedings in the CLF group. There were no conversions to an open approach. Mean length of hospital stay (2.8 vs. 3.3 days; p = 0.086) and symptomatic outcome thirty days postoperatively (10% vs. 15% with ongoing PPI therapy; p = 1.0 and 25% vs. 20% with persisting mild dysphagia; p = 1.0) was similar in both groups. Costs were higher for RALF than for CLF (€ 3244 vs. € 2743, p = 0.003).ConclusionIn comparison with CLF, operative time can be shorter for RALF if performed by an experienced team. However, costs are higher and short-term outcome is similar. Thus, RALF can not be favoured over CLF regarding perioperative outcome.

Augmented reality visualization during laparoscopic radical prostatectomy.

PURPOSE We present an augmented reality (AR) navigation system that conveys virtual organ models generated from transrectal ultrasonography (TRUS) onto a real laparoscopic video during radical prostatectomy. By providing this additional information about the actual anatomy, we can support surgeons in their working decisions. This work reports the systems first in-vivo application. MATERIALS AND METHODS The system uses custom-developed needles with colored heads that are inserted into the prostate as soon as the organ surface is uncovered. These navigation aids are once segmented in three-dimensional (3D) TRUS data that is acquired right after the placement of the needles and then continuously tracked in the laparoscopic video images by the surgical navigation system. The navigation system traces the navigation aids in real time and computes a registration between TRUS image and laparoscopic video based on the two-dimensional-three dimensional (2D-3D) point correspondences. With this registration, the system correctly superimposes TRUS-based 3D information on an additional AR monitor placed next to the normal laparoscopic screen. Surgical navigation guidance took place until the prostate was removed from the rectal wall. Finally, the navigation aids were removed together with the specimen inside the specimen bag. RESULTS The initial human in-vivo application of the surgical navigation system was successful. No complications occurred, the prostate was removed together with the navigation aids, and the system supported the surgeons as intended with an AR visualization in real time. In case of tissue deformations, changes in the spatial configuration of the navigation aids are detected, which preserves the system from erroneous navigation visualization. CONCLUSIONS Feasibility of the navigation system was shown in the first in-vivo application. TRUS information could be superimposed via AR in real time. To show the benefit for the patient, results obtained from a larger number of trials are needed.

Signs of reperfusion injury following CO2 pneumoperitoneum: an in vivo microscopy study

BackgroundDuring laparoscopic surgery, pneumoperitoneum is generally established by means of carbon dioxide (CO2) insufflation which may disturb hepatic microperfusion. It has been suggested that the desufflation at the end of the procedure creates a model of reperfusion in a previously ischemic liver, thus predisposing it to reperfusion injury.MethodsTo study the effects of pneumoperitoneum on hepatic microcirculation, Sprague-Dawley rats underwent pneumoperitoneum with an intraabdominal pressure of 8 or 12 mmHg for 90 min. Subsequently, in vivo microscopy was performed to assess intrahepatic microcirculation and transaminases were measured to index liver injury.ResultsA CO2 pneumoperitoneum of 8 mmHg did not change serum transaminases; however, further increase of intraperitoneal pressure to 12 mmHg significantly increased AST, ALT, and LDH measured after desufflation to almost 1.5 times as much as control values of 49 ± 5 U/L, 31 ± 3 U/L, and 114 ± 12 U/L. In parallel, in all subacinar zones the permanent adherence of both leukocytes and platelets to the endothelium increased by about sixfold and threefold, respectively. Furthermore, Kupffer cells labeled with latex beads as an index for their activation were significantly increased compared to controls.ConclusionThis in vivo observation demonstrated traces of reperfusion injury in liver induced by the insufflation and desufflation of CO2 pneumoperitoneum. The clinical relevance of this finding and the issue of using hepatoprotective substances to prevent this injury should be further investigated.

Robotic suturing: technique and benefit in advanced laparoscopic surgery.

Suturing is one of the main tasks in advanced laparoscopic surgery, but limited degrees of freedom, 2D vision, fulcrum and pivoting effect make it difficult to perform. Robotic systems provide corresponding solutions as three‐dimensional (3D) view, intuitive motion and additional degrees of freedom. This review evaluates these benefits for their impact on suturing in experimental and clinical studies. The Medline database was searched for “robot*, telemanipulat* and laparoscop*”. A total of 1150 references were found and further limited to “suturing” for experimental evaluation, finding 89 references. All references were considered for information on robotic suturing in advanced laparoscopy. Further references were obtained through cross‐referencing the bibliography cited in each work. In experimental studies current robotic systems have proven their superior suturing capabilities compared to conventional laparoscopic techniques, mainly attributed to 3D visualization and full seven degrees of freedom. In clinical studies these benefits have not yet been sufficiently reproduced. Robotic systems have to prove the benefits shown in experimental studies for suturing tasks in clinical applications. Robotic devices shorten the learning curve of laparoscopic procedures. Further clinical trials focusing on anastomosis time are needed to assess this question.

Tracking of instruments in minimally invasive surgery for surgical skill analysis

Intraoperative assistance systems aim to improve the quality of the surgery and enhance the surgeon’s capabilities. Preferable would be a system which provides support depending on the surgery context and surgical skills accomplished. Therefore, the automated analysis and recognition of surgical skills during an intervention is necessary. In this paper a robust tracking of instruments in minimally invasive surgery based on endoscopic image sequences is presented. The instruments were not modified and the tracking was tested on sequences acquired during a real intervention. The generated trajectory of the instruments provides information which can be further used for surgical gesture interpretation.

Soft tissue navigation for laparoscopic partial nephrectomy

PurposeMinimally invasive surgery of kidney cancer has become a standard therapy method for renal carcinomas. Due to improvements in diagnosis, carcinomas tend to be detected with a smaller size, which often allows for a tissue sparing, laparoscopic partial nephrectomy (LPN). Successful LPN requires a safe resection line inside the kidney, which spares most of healthy tissue, while assuring the complete tumor removal. This paper proposes an approach for a real-time visualization aid during LPN.MethodsA surgical soft tissue navigation system for laparoscopic was designed, implemented and tested in vitro. The system enhances the surgeon’s perception to provide decision guidance directly before initiation of kidney resection. Preoperative planning, intraoperative imaging, and real-time image processing are incorporated in a system that can enhance an endoscope’s image by superimposing relevant medical information like tumor infiltrated tissue and risk structures. This system has a flexible design to facilitate its integration into surgical work flows. The system evaluation was divided into two parts: (1) a virtual evaluation environment, which allows for simulation of all involved system parameters; (2) in vitro surgeries were performed using a laparoscopic training unit to evaluate the overall robustness and accuracy of the navigation system with real data.ResultsThe system was implemented and tested in vitro with favorable results. Real-time video recording of its operation was done to demonstrate the ability to simultaneously visualize the renal collecting system, major blood vessels, and abnormal lesion.ConclusionLaparoscopic partial nephrectomy can benefit from surgical computer assistance with preoperative planning, intraoperative imaging, and real time guidance integrated in a single system. The presented surgical navigation approach is suitable for testing in an intraoperative environment with human patients undergoing LPN.

Development and evaluation of a training module for the clinical introduction of the da Vinci robotic system in visceral and vascular surgery

BackgroundWith the increasing use of the surgical robotic system in the clinical arena, appropriate training programs and assessment systems need to be established for mastery of this new technology. The authors aimed to design and evaluate a clinic-like training program for the clinical introduction of the da Vinci robotic system in visceral and vascular surgery.MethodsFour trainees with different surgical levels of experience participated in this study using the da Vinci telemanipulator. Each participant started with an initial evaluation stage composed of standardized visceral and vascular operations (cholecystectomy, gastrotomy, anastomosis of the small intestine, and anastomosis of the aorta) in a porcine model. Then the participants went on to the training stage with the rat model, performing standardized visceral and vascular operations (gastrotomy, anastomosis of the large and small intestines, and anastomosis of the aorta) four times in four rats. The final evaluation stage was again identical to the initial stage. The operative times, the number of complications, and the performance quality of the participants were compared between the two evaluation stages to assess the impact of the training stage on the results.ResultsThe operative times in the final evaluation stage were considerably shorter than in the initial evaluation stage and, except for cholecystectomies, all the differences reached statistical significance. Also, significantly fewer complications and improved quality for each operation in the final evaluation stage were documented, as compared with their counterparts in the initial evaluation stage. These improvements were recorded at each level of experience.ConclusionsThe presented experimental small and large animal model is a standardized and reproducible training method for robotic surgery that allows evaluation of the surgical performance while shortening and optimizing the learning-curve.