Repair of parastomal hernias with the intraperitoneal funnel meshes IPST-R and IPST.

The treatment of parastomal hernias (PSH) represents a major challenge in hernia surgery. Various techniques have been reported with different outcomes in terms of complication and recurrence rates. The aim of this study is to share our initial experience with the implantation of the DynaMesh-IPST-R and -IPST, intraperitoneal funnel meshes made of polyvinylidene fluoride (PVDF). This is a retrospective observational cohort study of patients treated for PSH between March 2019 and April 2023 using the chimney technique with the intraperitoneal funnel meshes IPST-R or IPST. The primary outcome was recurrence and the secondary outcomes were intraoperative and postoperative complications, the latter assessed using the Clavien-Dindo classification. A total of 21 consecutive patients were treated with intraperitoneal PVDF funnel meshes, 17 with IPST-R and 4 with IPST. There were no intraoperative complications. Overall, no complications occurred in 61.9% (n = 12) of the patients. Major postoperative complications (defined as Clavien-Dindo ≥ 3b) were noted in four cases (19.0%). During the mean follow-up period of 21.6 (range 4.8-37.5) months, one patient (4.8%) had a recurrence. In conclusion, for the treatment of parastomal hernias, the implantation of IPST-R or IPST mesh has proven to be efficient, easy to handle, and very safe. In particular, the low recurrence rate of 4.8%, which is in line with the current literature, is convincing. However, a larger number of patients would improve the validity of the results.

Diagnostic Accuracy of MMP-8 and IL-6-Based Point-of-Care Testing to Detect Peritoneal Dialysis-Related Peritonitis: A Single-Center Experience.

BACKGROUND: Peritoneal dialysis-related peritonitis (PDRP) is the most common complication of peritoneal dialysis (PD), which can lead to poor outcomes if not diagnosed and treated early. We aimed to investigate the diagnostic accuracy of MMP-8 and IL-6-based point-of-care tests (POCTs) in diagnosing PDRP in PD patients. METHODS: This retrospective chart review study was conducted at a comprehensive kidney center in Qatar. It involved all adult PD patients who underwent PDRP from July 2018 to October 2019 and for whom MMP-8 and IL-6-based POCTs were used to diagnose presumptive peritonitis. Measures of diagnostic accuracy were computed. Peritoneal fluid effluent analysis was the reference standard. RESULTS: We included 120 patients (68 [56.7%] females, ages 55.6 ± 15.6 years, treatment duration 39.5 ± 30.4 months [range: 5-142 months]). In this population, MMP-8 and IL-6-based POCTs yielded 100% in all dimensions of diagnostic accuracy (sensitivity, specificity, positive and negative predictive values). CONCLUSIONS: MMP-8 and IL-6-based POCTs might be helpful in the early detection of PDRP. This monocentric observation requires further confirmation in a prospective multicentric setting.

Differential diagnoses of inguinal swellings: a case series of atypical diagnoses.

This case series highlights the importance of a thorough differential diagnosis in patients with groin swelling, often mistaken for inguinal hernias. It presents three patients with groin swelling initially suspected of having inguinal hernias but diagnosed differently upon further investigation. Patient 1 had a recurrence of endometrial adenocarcinoma in the right groin, Patient 2 had penile carcinoma with left inguinal metastasis, and Patient 3 had a metastasis of prostate carcinoma in the left groin. These cases underline the need to consider various pathologies beyond the common diagnosis of inguinal hernia. Accurate diagnosis requires a careful clinical examination and appropriate diagnostic tools, ensuring correct treatment.

Transanal small bowel evisceration: A case report and literature review.

INTRODUCTION: Transanal small bowel evisceration remains a rarely recorded emergent situation in the scientific literature. This article describes the rather seldom complication of a non-treated long standing rectal prolapse presenting in the form of transanal prolapse of the small bowel due to rectal perforation. PRESENTATION OF CASE: We present the case of an 84 year old female, who presented to our emergency department with transanal evisceration of the small bowel. DISCUSSION: This rare case presentation led us to perform an accompanying review of the literature, using Pubmed® searching for the words "transanal evisceration", "rectal prolapse", and "rectal perforation". We discuss the outcomes of our literature review, possible pathogenesis and the available treatment options. CONCLUSION: Although transanal evisceration of small bowel presents a rare emergency, having the knowledge of this condition would help early recognition of this incidence and hopefully lead to early treatment, which would avoid drastic consequences as a result of small bowel strangulation.

Survival Outcomes of Hepatectomy in Gastric Cancer Liver Metastasis: A Systematic Review and Meta-Analysis.

Gastric cancer liver metastasis (GCLM) is a contraindication for surgical treatment in current guidelines. However, the results of recent studies are questioning this paradigm. We assessed survival outcomes and their predictors following hepatectomy for GCLM in a systematic review of studies published from 2000 to 2022 according to PRISMA guidelines. We identified 42,160 references in four databases. Of these, 55 articles providing data from 1990 patients fulfilled our criteria and were included. We performed a meta-analysis using random-effects models to assess overall survival (OS) and disease-free survival (DFS) at one, three, and five years post-surgery. We studied the impact of potential prognostic factors on survival outcomes via meta-regression. One, three, and five years after surgery, OS was 69.79%, 34.79%, and 24.68%, whereas DFS was 41.39%, 23.23%, and 20.18%, respectively. Metachronous presentation, well-to-moderate differentiation, small hepatic tumoral size, early nodal stage, R0 resection, unilobar compromisation, and solitary lesions were associated with higher overall survival. Metachronous presentation, smaller primary tumoral size, and solitary metastasis were linked to longer DFS. The results of our meta-analysis suggest that hepatectomy leads to favorable survival outcomes in patients with GCLM and provides data that might help select patients who will benefit most from surgical treatment.

Clinical implementation of the Versius robotic surgical system in visceral surgery-A single centre experience and review of the first 175 patients.

BACKGROUND: Robotic surgical systems introduce new opportunities for the minimal accessed surgeon. The combination of three-dimensional magnified vision and articulated instruments with seven degrees of freedom provide a good and safe alternative to laparoscopic surgery. Indeed some of these features may support the case that robotic surgery may be better than conventional surgery. In this study, we report our experience of robotic surgery by using the first open console, modular robotic platform in Germany, the Versius Surgical System®. METHODS: We implemented the Versius Surgical System® in April 2021 at our centre. Since then, 175 patients received robotic assisted surgery. All patients were included in this study. Data were analysed by using the SPSS (IBM Statistics) Software. RESULTS: 175 patients underwent robotic surgery. We started the implementation of the system by performing cholecystectomy. After the first 50 successful operations, we began to perform robotic assisted oncological resections. We saw a learning curve with improvements in total operative time and console time until reaching a standard similar to conventional laparoscopic surgery. The perioperative complication-ratio was equivalent for operations matched the histopathological outcome (MERCURY graduation, R0-staus) at oncological resections. However, four patients had to be revised because of secondary bleeding. Interestingly the total hospital stay for right sided hemicolectomy and oesophagus-resection was shorter than in laparoscopic surgery. In our opinion, the Versius Surgical System® seems to be a good, promising system and a safe alternative to other robotic systems, although any comparison is still missing. The open design enabling a better communication between console surgeon and bedside-unit assistant as well as the mobile bedside units are very interesting and allow more flexibility. Nevertheless, there are limitations of the system that require a direct comparison with other robotic systems as well as continuous advancement.

Minimally invasivE versus open total GAstrectomy (MEGA): study protocol for a multicentre randomised controlled trial (DRKS00025765).

INTRODUCTION: The only curative treatment for most gastric cancer is radical gastrectomy with D2 lymphadenectomy (LAD). Minimally invasive total gastrectomy (MIG) aims to reduce postoperative morbidity, but its use has not yet been widely established in Western countries. Minimally invasivE versus open total GAstrectomy is the first Western multicentre randomised controlled trial (RCT) to compare postoperative morbidity following MIG vs open total gastrectomy (OG). METHODS AND ANALYSIS: This superiority multicentre RCT compares MIG (intervention) to OG (control) for oncological total gastrectomy with D2 or D2+LAD. Recruitment is expected to last for 2 years. Inclusion criteria comprise age between 18 and 84 years and planned total gastrectomy after initial diagnosis of gastric carcinoma. Exclusion criteria include Eastern Co-operative Oncology Group (ECOG) performance status >2, tumours requiring extended gastrectomy or less than total gastrectomy, previous abdominal surgery or extensive adhesions seriously complicating MIG, other active oncological disease, advanced stages (T4 or M1), emergency setting and pregnancy.The sample size was calculated at 80 participants per group. The primary endpoint is 30-day postoperative morbidity as measured by the Comprehensive Complications Index. Secondary endpoints include postoperative morbidity and mortality, adherence to a fast-track protocol and patient-reported quality of life (QoL) scores (QoR-15, EUROQOL EuroQol-5 Dimensions-5 Levels (EQ-5D), EORTC QLQ-C30, EORTC QLQ-STO22, activities of daily living and Body Image Scale). Oncological endpoints include rate of R0 resection, lymph node yield, disease-free survival and overall survival at 60-month follow-up. ETHICS AND DISSEMINATION: Ethical approval has been received by the independent Ethics Committee of the Medical Faculty, University of Heidelberg (S-816/2021) and will be received from each responsible ethics committee for each individual participating centre prior to recruitment. Results will be published open access. TRIAL REGISTRATION NUMBER: DRKS00025765.

Robotic Living Donor Right Hepatectomy: A Systematic Review and Meta-Analysis.

The introduction of robotics in living donor liver transplantation has been revolutionary. We aimed to examine the safety of robotic living donor right hepatectomy (RLDRH) compared to open (ODRH) and laparoscopic (LADRH) approaches. A systematic review was carried out in Medline and six additional databases following PRISMA guidelines. Data on morbidity, postoperative liver function, and pain in donors and recipients were extracted from studies comparing RLDRH, ODRH, and LADRH published up to September 2020; PROSPERO (CRD42020214313). Dichotomous variables were pooled as risk ratios and continuous variables as weighted mean differences. Four studies with a total of 517 patients were included. In living donors, the postoperative total bilirubin level (MD: −0.7 95%CI −1.0, −0.4), length of hospital stay (MD: −0.8 95%CI −1.4, −0.3), Clavien−Dindo complications I−II (RR: 0.5 95%CI 0.2, 0.9), and pain score at day > 3 (MD: −0.6 95%CI −1.6, 0.4) were lower following RLDRH compared to ODRH. Furthermore, the pain score at day > 3 (MD: −0.4 95%CI −0.8, −0.09) was lower after RLDRH when compared to LADRH. In recipients, the postoperative AST level was lower (MD: −0.5 95%CI −0.9, −0.1) following RLDRH compared to ODRH. Moreover, the length of stay (MD: −6.4 95%CI −11.3, −1.5) was lower after RLDRH when compared to LADRH. In summary, we identified low- to unclear-quality evidence that RLDRH seems to be safe and feasible for adult living donor liver transplantation compared to the conventional approaches. No postoperative deaths were reported.

Effects of digitalized university curriculum-associated teaching on the equilibrium of autonomic neurophysiology and disposition of learners in medical school (EDUCATE-AND-LEARN): protocol for a randomized crossover study.

BACKGROUND: Homoeostasis of the autonomic nervous system (ANS) contributes to cognitive functional integrity in learners and can be greatly influenced by emotions and stress. While moderate stress can enhance learning and memory processes, long-term stress compromises learning performance in a face-to-face classroom environment. Integrative online learning and communication tools were shown to be beneficial for visualization and comprehension but their effects on the ANS are poorly understood. We aim to assess the effects of video conference-supported live lectures compared to on-site classroom teaching on autonomic functions and their association with learning performance. METHODS AND DESIGN: Fifty mentally and physically healthy medical students will be enrolled in a randomized two-period crossover study. Subjects will attend a seminar, which is held in face-to-face and simultaneously transmitted via videoconference. Subjects will be allocated in two arms in a randomized sequence determining the order in which both seminar settings will be attended. At baseline and throughout the interactive seminar subjects will undergo detailed autonomic testing comprising neurocardiac (heart rate variability), sudomotor (sympathetic skin response), neurovascular (laser Doppler flowmetry) and pupillomotor (pupillography) function. Furthermore, learning progress will be evaluated using pre- and post-tests on the seminar subject and emotions will be assessed using profile of mood state (POMS) questionnaire. STATISTICAL ANALYSIS: Carryover effects will be handled using a two-way repeated measures (mixed model). Between-group differences (baseline vs face-to-face vs videoconference) will be determined using one-way analysis of variance ANOVA followed by Student-Newman-Keul test. LIMITATIONS AND STRENGTHS: This study may elucidate complex interactions between autonomic and emotional dynamics during conventional on-site and video conference-based teaching, thus providing a basis for customized learning and teaching methods. Understanding and utilizing advanced distance learning strategies is particularly important during the current pandemic, which has been limiting on-site teaching dramatically in nearly all countries of the world.

Case Report: Eighteen Month Relapse- Free Survival Following Radical Multidisciplinary Oncological Treatment in a 68-Year-Old Male Patient With Histiocytic Sarcoma.

INTRODUCTION: Histiocytic Sarcoma (HS) is a rare and aggressive malignancy, and patients can present with rapid tumor growth and invasion. The optimal diagnostic and therapeutic management is unknown since only a few cases have been published. Here we report a patient with histiocytic sarcoma of the right groin. CASE: A 68 year-old male patient presented to our hospital with suspicion of a superinfected atheroma of the right groin. Computed tomography showed an abdominal tumor of unknown entity. Detailed assessment including immunohistochemically evaluation of biopsy material confirmed HS. The patient underwent radical tumor resection including compartment-resection of the right thigh. During five additional cycles of chemotherapy over a period of 1.5 years he remained relapse-free. SUMMARY: Diagnostic work up and treatment of HS is challenging, as there is a paucity of clinical reports and lack of standard guidelines for care. In the present case report, aggressive multidisciplinary treatment resulted in good clinical outcome, however, further studies evaluating this approach in similar patients are needed.

Association of history of cerebrovascular disease with severity of COVID-19.

OBJECTIVE: To determine whether a history of cerebrovascular disease (CVD) increases risk of severe coronavirus disease 2019 (COVID-19). METHODS: In a retrospective multicenter study, we retrieved individual data from in-patients treated March 1 to April 15, 2020 from COVID-19 registries of three hospitals in Saxony, Germany. We also performed a systematic review and meta-analysis following PRISMA recommendations using PubMed, EMBASE, Cochrane Library databases and bibliographies of identified papers (last search on April 11, 2020) and pooled data with those deriving from our multicenter study. Of 3762 records identified, 11 eligible observational studies of laboratory-confirmed COVID-19 patients were included in quantitative data synthesis. Risk ratios (RR) of severe COVID-19 according to history of CVD were pooled using DerSimonian and Laird random effects model. Between-study heterogeneity was assessed using Cochran's Q and I2-statistics. Severity of COVID-19 according to definitions applied in included studies was the main outcome. Sensitivity analyses were conducted for clusters of studies with equal definitions of severity. RESULTS: Pooled analysis included data from 1906 laboratory-confirmed COVID-19 patients (43.9% females, median age ranging from 39 to 76 years). Patients with previous CVD had higher risk of severe COVID-19 than those without [RR 2.07, 95% confidence interval (CI) 1.52-2.81; p < 0.0001]. This association was also observed in clusters of studies that defined severe manifestation of the disease by clinical parameters (RR 1.44, 95% CI 1.22-1.71; p < 0.0001), necessity of intensive care (RR 2.79, 95% CI 1.83-4.24; p < 0.0001) and in-hospital death (RR 2.18, 95% CI 1.75-2.7; p < 0.0001). CONCLUSION: A history of CVD might constitute an important risk factor of unfavorable clinical course of COVID-19  suggesting a need of tailored infection prevention and clinical management strategies for this population at risk.

Single-Incision Multiport/Single Port Laparoscopic Abdominal Surgery (SILAP): A Prospective Multicenter Observational Quality Study.

BACKGROUND: Increasing experience with minimally invasive surgery and the development of new instruments has resulted in a tendency toward reducing the number of abdominal skin incisions. Retrospective and randomized prospective studies could show the feasibility of single-incision surgery without any increased risk to the patient. However, large prospective multicenter observational datasets do not currently exist. OBJECTIVE: This prospective multicenter observational quality study will provide a relevant dataset reflecting the feasibility and safety of single-incision surgery. This study focuses on external validity, clinical relevance, and the patients' perspective. Accordingly, the single-incision multiport/single port laparoscopic abdominal surgery (SILAP) study will supplement the existing evidence, which does not currently allow evidence-based surgical decision making. METHODS: The SILAP study is an international prospective multicenter observational quality study. Mortality, morbidity, complications during surgery, complications postoperatively, patient characteristics, and technical aspects will be monitored. We expect more than 100 surgical centers to participate with 5000 patients with abdominal single-incision surgery during the study period. RESULTS: Funding was obtained in 2012. Enrollment began on January 01, 2013, and will be completed on December 31, 2018. As of January 2016, 2119 patients have been included, 106 German centers are registered, and 27 centers are very active (>5 patients per year). CONCLUSIONS: This prospective multicenter observational quality study will provide a relevant dataset reflecting the feasibility and safety of single-incision surgery. An international enlargement and recruitment of centers outside of Germany is meaningful. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00004594; https://drks-neu.uniklinik-freiburg.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00004594 (Archived by WebCite at http://www.webcitation.org/6jK6ZVyUs).

Outcomes and prognostic factors in gallbladder cancer: a single-centre experience.

INTRODUCTION: Gallbladder cancer is the most common malignant tumour of the biliary system with an extraordinarily poor prognosis. In this study, we retrospectively evaluated forty-two patients with histologically proven gallbladder cancer. PATIENTS AND METHODS: Estimated survival rates were calculated by the Kaplan-Meier method, and differences were assessed using the logrank test. The GKR (combined registry of cancer) and demographic data were used to gain information on community cancer statistics. RESULTS: In this study, patients with metastases showed poorer survival rates. Furthermore, the survival was significantly better in patients with R0 resections, smaller tumour sizes and without lymph node infiltration. T stage, M stage and R stage were independent prognostic parameters. Sex and age had no significant effect on survival. Also, we found that patients with incidental gallbladder cancer and those with cholecystolithiasis showed significantly better survival rates. Demographic analyses of the study group confirmed a high coverage of our institution for incident cases in our catchment area and no significant regional deviations from the expected incidence of gallbladder cancer. CONCLUSION: Despite differences in the incidence in different geographical areas, gallbladder cancer appears to be fairly normally distributed in Western Pomerania, a predominantly rural area of Northeastern Germany. Coverage of incident cases in our catchment area was high. T stage, M stage and R stage were independent prognostic factors in our study. We conclude that, whenever possible, an R0 resection should be the surgical goal in all patients staged resectable before surgery, but heroic resections in patients with highly advanced cancer disease or severe accompanying non-tumour diseases are not warranted.

IgG4-related systemic disease--a rare indication for multi-visceral transplantation.

Multivisceral transplantations (MVT) are rarely performed procedures. In this case report, we present a 37-year-old male patient with a large retroperitoneal tumor. After exclusion of malignancy, we performed MVT (distal stomach, liver, pancreas, and small bowel). After a follow-up of 1 year, the patient is in good clinical condition. Histologic examination revealed a chronic sclerosing IgG4-associated disease. Our case shows that MVT can be successfully performed in this rare disease.

Hepatothorax after right-sided diaphragmatic rupture mimicking a pleural effusion: a case report.

INTRODUCTION: Diaphragmatic ruptures are a rare condition with an incidence of about 0.8-5.8% after blunt thoracoabdominal trauma. Right sided ruptures accompanied by a displacement of intraabdominal organs are very uncommon and account for approximately 5-19% of all diaphragmatic ruptures. The majority of diaphragmatic ruptures are based on high speed motor vehicle accidents (MVA) and high falls. CASE PRESENTATION: Herein we report a case of a 58-year old woman after a high-speed MVA with a right-sided diaphragmatic rupture and displacement of the liver into the thorax, mimicking a pleural effusion. CONCLUSION: Due to the low incidence and frequently present masking injuries, diagnosis is difficult and virtually always delayed. Thus, a high index of suspicion is important in cases of blunt thoracoabdominal trauma, as the 24 h mortality-rate of a right sided diaphragmatic rupture is up to 30%. In these situations a spiral CT-scan is the diagnostic tool of choice. Surgical intervention using an abdominal approach via a hockey-stick shaped incision is necessary even for small tears. Part of the polytrauma management following high speed MVAs is a critical review of the radiologic imaging.

Laparoscopic colorectal resection for benign polyps not suitable for endoscopic polypectomy.

BACKGROUND AND AIMS: Endoscopic polypectomy still remains the cornerstone of therapy for colorectal polyps and adenomas. However, if colorectal polyps are too large or not accessible for endoscopic ablation or cannot be removed without an increased risk for perforation, operative procedures are required. In such circumstances, laparoscopic resection represents a minimally invasive alternative. MATERIALS AND METHODS: Between January 1993 and December 2004, more than 2,500 endoscopic polypectomies were performed at the Department of Surgery, University of Schleswig-Holstein, Campus Lübeck, Germany. In patients which could not be treated by endoscopic polypectomy due to size, location, and/or risk of complications, a laparoscopic colorectal resection was performed. All data were prospectively assessed in our "colorectal resection" database. RESULTS: The database analysis revealed 58 patients with endoscopically not resectable colorectal polyps who underwent a laparoscopic colorectal resection (intend to treat). In 54 patients, the operative procedure could be finished by the laparoscopic approach (study population). The conversion rate was 6.9% (four of 58). An ileocolic resection was performed in 20 patients (37.0%), and 14 patients (25.9%) underwent an anterior rectal resection. A right colectomy was necessary in 12 patients (22.2%), and six patients (11.1%) underwent a sigmoid resection. In the remaining two patients, a left colectomy and a resection of the transverse colon were performed. Intra- and postoperative complications occurred in five patients (9.3%). Perioperative mortality was not registered. The histopathological work-up revealed benign disease in all cases. CONCLUSION: Laparoscopic resection of colorectal polyps is a safe and minimally invasive technique for the management of benign colorectal tumors. Thus, the laparoscopic approach to endoscopically not resectable polyps enriches the therapeutic spectrum.

Giant bladder diverticulum as a rare cause of intestinal obstruction: report of a case.

We report a case of intestinal obstruction as an unusual manifestation of bladder diverticulum. To our knowledge, this is the first report of a giant bladder diverticulum causing acute abdomen as a result of mechanical bowel obstruction.

Development of a perfused ex vivo tumor-mimic model for the training of laparoscopic radiofrequency ablation.

BACKGROUND: Laparoscopic radiofrequency ablation (RFA) is a safe and effective method for tumor destruction in patients with unresectable liver tumors. However, accurate probe placement using laparoscopic ultrasound guidance is required to achieve complete tumor ablation. This study aimed to develop a perfusable ex vivo tumor-mimic model for laparoscopic radiofrequency ablation training. METHODS: After rinsing the prepared liver vessels with anticoagulants, porcine livers were perfused. Tumor-mimics were created by injecting a mixture consisting of 3% agarose, 3% cellulose, 7% glycerol, and 0.05% methylene blue, creating hyperechoic lesions in ultrasound. Heparinized porcine blood was used as perfusion medium. Continuous perfusion of the porcine liver was provided by connection of a pump system to the portal vein and the vena cava inferior. Laparoscopic RFA techniques were taught using a laparoscopic pelvi-trainer. RESULTS: A total of 30 laparoscopic ablations were performed in four porcine livers. The simulated "tumors" were clearly visible on laparoscopic ultrasound and not felt during placement of the RFA probe. In addition, color duplex ultrasound showed clear signals indicating for a sufficient liver perfusion. CONCLUSION: Laparoscopic RFA requires advanced laparoscopic ultrasound skills for an accurate placement of the RFA probe. The perfused tumor-mimic model presented is a safe, easy, effective, and economic method to improve and train laparoscopic RFA skills on porcine liver tissue.

Technical aspects and feasibility of laparoscopic ultrasound navigation in radiofrequency ablation of unresectable hepatic malignancies.

PURPOSE: Laparoscopic radiofrequency ablation is safe, practicable, and combines minimally invasive surgery with the advantages of laparotomy. However, application of the laparoscopic freehand puncture is restricted because of capnoperitoneum and the consequent fixation of the needle on two different points. The use of a laparoscopic ultrasound probe with a canal for puncture can solve this problem and improve precision. However, a stiff needle limits the necessary angulation that is needed to reach right-lateral and cranial liver metastases. Therefore we present a new navigation tool for laparoscopic interventions. MATERIALS AND METHODS: The US Guide 2000 (Ultra Guide, Tirat Hacarmel, Israel) is an independent navigation system compatible with all ultrasound machines and has six degrees of freedom. After proper evaluation of this system under operating room conditions during transcutaneous radiofrequency ablation, we used this technique in laparoscopic radiofrequency ablation. A special adapter was developed to attach the ultrasound-based navigation system to a laparoscopic ultrasound probe. After calibrating the system with an ultrasound phantom, laparoscopic navigation in a liver organ model was studied. RESULTS: Even in cases of angulation of the ultrasound probe no disturbances of the navigation system could be detected. Anatomic landmarks in the liver could be safely reached. No interaction between the navigation system and the laparoscopic ultrasound probe or operating instruments was observed. CONCLUSION: Our preliminary results show the feasibility of this technique in laparoscopic radiofrequency ablation. The use of an ultrasound-based laparoscopic inline navigation system offers the possibility of out-of-plane needle placement and could combine the flexibility of freehand puncture with the accuracy of a canal for puncture. This could increase the safety and accuracy of punctures.