Prof. Frederic Ris comes from Switzerland, he qualified in 1999 from the Geneva University Medical School (Switzerland). He is since January 2012 a staff surgeon, head of colorectal surgery, in the Visceral Surgery Service at the Geneva University Hospitals.After 2 years of research, he undertook his general surgical training in Switzerland and in St-Luc Hospital in Belgium (2006), to achieve his general surgical specialist exam in 2008 (FMH). He performed a colorectal fellowship at Oxford University Hospitals between 2010 and 2011.He is an European board certified colorectal and proctology surgeon (EBSQ 2011) and achieve his visceral surgical exam in 2013 (FMH).He has been awarded an MD degree for his research into MRI imaging of islet cells and a Privat Docent (PD, senior lecturer) for his research on fluorescence imaging. His research won prizes including the Swiss Surgery Society Award and the Marc-Claude Marti Award. He has published over 260 journal articles and book chapters with a H index of 44. His main projects are on 4 different aspects, a.)colorectal and oncologic surgery, b.)pelvic floor and proctology, c.)new technologies and d.) teaching surgery. He has a special interest in Near Infra Red (NIR) imaging for perfusion and lymphnode mapping and on enhanced recovery management.He is expert in minimally invasive colorectal surgery (IBD and cancer), pelvic floor disorders and oncologic surgery and has developed an exenteration program. He is also responsible for the HIPEC program and one of the founders of the swiss peritoneal cancer group.He is vice director of the Geneva University hospitals cancer center since 2022
Background Minimally invasive surgery (MIS), including laparoscopic and robotic approaches, is wi... more Background Minimally invasive surgery (MIS), including laparoscopic and robotic approaches, is widely adopted in elective digestive surgery, but selectively used for surgical emergencies. The present position paper summarizes the available evidence concerning the learning curve to achieve proficiency in emergency MIS and provides five expert opinion statements, which may form the basis for developing standardized curricula and training programs in emergency MIS. Methods This position paper was conducted according to the World Society of Emergency Surgery methodology. A steering committee and an international expert panel were involved in the critical appraisal of the literature and the development of the consensus statements. Results Thirteen studies regarding the learning curve in emergency MIS were selected. All but one study considered laparoscopic appendectomy. Only one study reported on emergency robotic surgery. In most of the studies, proficiency was achieved after an average...
Background Various environmental risk factors have been associated with the pathogenesis of infla... more Background Various environmental risk factors have been associated with the pathogenesis of inflammatory bowel disease. In this study we aimed to identify lifestyle factors that affect the onset of Crohn’s disease and ulcerative colitis. Methods 2294 patients from the Swiss IBD Cohort Study received a questionnaire regarding physical activity, nutritional habits and status of weight. In addition, a control group was formed comprising patients’ childhood friends, who grew up in a similar environment. Results Overall, 1111 questionnaires were returned (response rate: 48.4%). Significantly more patients with inflammatory bowel disease reported no regular practice of sport during childhood and beginning of adulthood compared to the control group (p = 0.0001). No association between intake of refined sugar and onset of inflammatory bowel disease was observed. More patients with Crohn’s disease compared to ulcerative colitis and controls suffered from overweight during childhood (12.8% vs...
Objective Observational studies have shown that fluorescence angiography (FA) decreases the incid... more Objective Observational studies have shown that fluorescence angiography (FA) decreases the incidence of anastomotic leak (AL) in colorectal surgery, but high-quality pooled evidence was lacking. Therefore, we aimed at confirming this preliminary finding using a systematic review and meta-analysis of randomised controlled trials (RCTs) in the field. Methods MEDLINE, Embase and CENTRAL were searched for RCTs assessing the effect of intra-operative FA versus standard assessment of bowel perfusion on the incidence of AL of colorectal anastomosis. The systematic review complied with the PRISMA 2020 and AMSTAR2 recommendations and was registered in PROSPERO. Pooled relative risk (RR) and pooled risk difference (RD) were obtained using models with random effects. Heterogeneity was assessed using the Q-test and quantified using the I2 value. Certainty of evidence was assessed using the GRADE Pro tool. Results One hundred and eleven articles were screened, 108 were excluded and three were k...
IntroductionIntraperitoneal dissemination is a major problem resulting in very poor prognosis and... more IntroductionIntraperitoneal dissemination is a major problem resulting in very poor prognosis and a rapid marked deterioration in the quality of life of patients. Pressurised intraperitoneal aerosol chemotherapy (PIPAC) is an emergent laparoscopic procedure aiming to maximise local efficacy and to reduce systemic side effects.Methods and analysisNab-PIPAC, a bicentre open-label phase IB, aims to evaluate safety of nab-paclitaxel and cisplatin association using in patients with peritoneal carcinomatosis (PC) of gastric, pancreatic or ovarian origin as ≥1 prior line of systemic therapy. Using a 3+3 design, sequential intraperitoneal laparoscopic application of nab-paclitaxel (7.5, 15, 25, 37.5, 52.5 and 70 mg/m2) and cisplatin (10.5 mg/m2) through a nebuliser to a high-pressure injector at ambient temperature with a maximal upstream pressure of 300 psi. Treatment maintained for 30 min at a pressure of 12 mm Hg and repeated4–6 weeks intervals for three courses total.A total of 6–36 pat...
BackgroundPatients undergoing colorectal surgery (CRS) have an increased risk of developing sexua... more BackgroundPatients undergoing colorectal surgery (CRS) have an increased risk of developing sexual disorders, attributed to different mechanisms. In this context, sexual function (SF) assessment of patients before and after surgery is essential: to identify risk factors for sexual disorders as well as to minimize their impact on overall quality of life (QoL), allowing them a satisfying relationship and sexual life.Material and methodsPatients over 18 years of age who underwent a CRS in the University Hospital of Geneva, Switzerland, between June 2014 and February 2016 were included. Our main objective was to compare and analyze the evolution of SF, QoL, and marital satisfaction (MS) before and after CRS. Specific and standardized tests were used.ResultsA cohort of 72 patients with a median age of 58.73 was analyzed. The majority of CRS was elective (91.5%). A percentage of 52.8% of patients underwent surgery for oncological reasons. There was no statistical difference in SF, sexual ...
Background Colon surgery has been shown to modulate the intestinal microbiota. Our objective was ... more Background Colon surgery has been shown to modulate the intestinal microbiota. Our objective was to characterize these changes using state-of-the-art next generation sequencing techniques. Methods We performed a single-centre prospective observational cohort study to evaluate the changes in the gut microbiota, i.e., taxon distribution, before and after elective oncologic colon surgery in adult patients with different antimicrobial prophylaxis regimens (standard prophylaxis with cefuroxime/metronidazole versus carbapenems for extended-spectrum beta-lactamase-producing Enterobacterales [ESBL-E] carriers). We obtained rectal samples on the day of surgery, intraoperative luminal samples, and rectal or stoma samples 3 days after surgery. We performed metataxonomic analysis based on sequencing of the bacterial 16S rRNA gene marker. Similarities and differences between bacterial communities were assessed using Bray–Curtis similarity, visualised using principal coordinates analysis and stat...
De Garengeot’s hernia is a rare entity in which the appendix is located within a femoral hernia a... more De Garengeot’s hernia is a rare entity in which the appendix is located within a femoral hernia and is almost invariably encountered incarcerated in an emergency setting. The clinical presentation is usually that of an incarcerated femoral hernia and is indistinguishable from other incarcerated femoral hernias. Here, we report on a 48-year-old female patient, known for a post-operative chronic seroma in the right groin since childhood, with a rare clinical presentation of a De Garengeot hernia. An abdominal CT-scan was performed, revealing an appendicitis with a stercolith in a femoral hernia. Generally, an inguinal approach alone (McVay procedure) is chosen and provides access for both appendectomy and hernia repair. In the absence of concomitant acute appendicitis, trans-abdominal pro-peritoneal laparoscopy (TAPP) could also be used as a single approach. In case of a rare presentation of acute appendicitis with probable contamination of the groin, we propose the double approach of...
Abstract Modulation of the microbiota of patients suffering from inflammatory bowel disease (IBD)... more Abstract Modulation of the microbiota of patients suffering from inflammatory bowel disease (IBD) with probiotics was suggested to avoid active disease and/or to lower the intensity of the active phase. Considering that the ecological niche of Bifidobacterium spp and Lactobacillus spp includes fermented dairy products, and that countries with highest dairy product consumption were those with lowest prevalence of IBD, we aimed at determining if consumption of dairy products could modulate the prevalence of IBD. Linear regression was performed on data from the Global Burden of Diseases, Injuries, and Risk Factors Study reporting the prevalence of IBD and from the European Association of Dairy Trade reporting national consumptions of dairy products. Consumption of milk, cheese or yoghourt per capita did not correlate with the prevalence of IBD at the national level in Western countries. Considering the limitations of this type of analysis, we recommend to continue investigating the effect of dairy product consumption on IBD by cross-sectional, longitudinal or interventional studies.
Resection of low rectal adenocarcinoma can be challenging in the narrow pelvis of male patients. ... more Resection of low rectal adenocarcinoma can be challenging in the narrow pelvis of male patients. Transanal total mesorectal excision (TaTME) appears to offer technical advantages for distal rectal tumours, and robotic-assisted transabdominal TME (rTME) was introduced in effort to improve operative precision and ergonomics. However, no study has comprehensively compared these approaches. The aim of the present study was to perform a systematic review of the literature to compare postoperative short-term outcomes in rTME and TaTME. A systematic online search (1974–July 2020) of MEDLINE, Embase, web of science and google scholar was conducted for trials, prospective or retrospective studies involving rTME, or TaTME for rectal cancer. Outcome variables included: hospital stay; operation duration, blood loss; resection margins; proportion of histologically complete resected specimens; lymph nodes; overall complications; anastomotic leak, and 30-day mortality. Sixty-two articles met the inclusion criteria, including 37 studies (3835 patients) assessing rTME resection, 23 studies (1326 patients) involving TaTME and 2 comparing both (165 patients). Operating time was longer in rTME (309.2 min, 95% CI 285.5–332.8) than in TaTME studies (256.2 min, 95% CI 231.5–280.9) (p = 0.002). rTME resected specimens had a larger distal resection margin (2.62 cm, 95% CI 2.35–2.88) than in TaTME studies (2.10 cm, 95% CI 1.83–2.36) (p = 0.007). Other outcome variables did not significantly differ between the two techniques. rTME provides similar pathological and short-term outcomes to TaTME and both are reasonable surgical approaches for patients with mid-to-low rectal cancer. To definitively answer the question of the optimal TME technique, we suggest a prospective trial comparing both techniques assessing long-term survival as a primary outcome.
AIM OF THE STUDY This European multicenter study aims to compare the results of laparoscopic vers... more AIM OF THE STUDY This European multicenter study aims to compare the results of laparoscopic versus laparotomy approach for the resection of splenic flexure colon carcinoma (SFC). PATIENTS AND METHODS Patients with SFC who required curative resection by laparoscopy (LAP) or laparotomy (OPEN) between 2000 and 2018 were included. Three types of interventions were considered: extended right hemi-colectomy, left hemi-colectomy and splenic flexure resection. The LAP and OPEN groups were matched according to propensity score and compared with Chi-square, Mann-Whitney tests, and multivariate regression models. Overall survival and recurrence-free survival were assessed using the Kaplan-Meier method. RESULTS The study population consisted of 399 patients, including 297 operated by LAP and 102 by OPEN. Extended right hemi-colectomy was performed in 35.8% of cases, left hemi-colectomy in 32.8% and splenic flexure resection in 31.4%. After propensity score matching, the LAP (n=64) and OPEN (n=64) groups were comparable for all pre-operative variables and tumor characteristics. The LAP group showed less blood loss and a shorter interval to return of transit and feeding compared to the OPEN group, regardless of the resection technique. There were no differences between the groups in terms of overall survival and 5-year recurrence-free survival. CONCLUSION These results support the application of laparoscopy for the resection of SFC.
Objective: The aim of this study was to determine the incidence of, and preoperative risk factors... more Objective: The aim of this study was to determine the incidence of, and preoperative risk factors for, positive circumferential resection margin (CRM) after transanal total mesorectal excision (TaTME). Background: TaTME has the potential to further reduce the rate of positive CRM for patients with low rectal cancer, thereby improving oncological outcome. Methods: A prospective registry-based study including all cases recorded on the international TaTME registry between July 2014 and January 2018 was performed. Endpoints were the incidence of, and predictive factors for, positive CRM. Univariate and multivariate logistic regressions were performed, and factors for positive CRM were then assessed by formulating a predictive model. Results: In total, 2653 patients undergoing TaTME for rectal cancer were included. The incidence of positive CRM was 107 (4.0%). In multivariate logistic regression analysis, a positive CRM after TaTME was significantly associated with tumors located up to 1...
Background Minimally invasive surgery (MIS), including laparoscopic and robotic approaches, is wi... more Background Minimally invasive surgery (MIS), including laparoscopic and robotic approaches, is widely adopted in elective digestive surgery, but selectively used for surgical emergencies. The present position paper summarizes the available evidence concerning the learning curve to achieve proficiency in emergency MIS and provides five expert opinion statements, which may form the basis for developing standardized curricula and training programs in emergency MIS. Methods This position paper was conducted according to the World Society of Emergency Surgery methodology. A steering committee and an international expert panel were involved in the critical appraisal of the literature and the development of the consensus statements. Results Thirteen studies regarding the learning curve in emergency MIS were selected. All but one study considered laparoscopic appendectomy. Only one study reported on emergency robotic surgery. In most of the studies, proficiency was achieved after an average...
Background Various environmental risk factors have been associated with the pathogenesis of infla... more Background Various environmental risk factors have been associated with the pathogenesis of inflammatory bowel disease. In this study we aimed to identify lifestyle factors that affect the onset of Crohn’s disease and ulcerative colitis. Methods 2294 patients from the Swiss IBD Cohort Study received a questionnaire regarding physical activity, nutritional habits and status of weight. In addition, a control group was formed comprising patients’ childhood friends, who grew up in a similar environment. Results Overall, 1111 questionnaires were returned (response rate: 48.4%). Significantly more patients with inflammatory bowel disease reported no regular practice of sport during childhood and beginning of adulthood compared to the control group (p = 0.0001). No association between intake of refined sugar and onset of inflammatory bowel disease was observed. More patients with Crohn’s disease compared to ulcerative colitis and controls suffered from overweight during childhood (12.8% vs...
Objective Observational studies have shown that fluorescence angiography (FA) decreases the incid... more Objective Observational studies have shown that fluorescence angiography (FA) decreases the incidence of anastomotic leak (AL) in colorectal surgery, but high-quality pooled evidence was lacking. Therefore, we aimed at confirming this preliminary finding using a systematic review and meta-analysis of randomised controlled trials (RCTs) in the field. Methods MEDLINE, Embase and CENTRAL were searched for RCTs assessing the effect of intra-operative FA versus standard assessment of bowel perfusion on the incidence of AL of colorectal anastomosis. The systematic review complied with the PRISMA 2020 and AMSTAR2 recommendations and was registered in PROSPERO. Pooled relative risk (RR) and pooled risk difference (RD) were obtained using models with random effects. Heterogeneity was assessed using the Q-test and quantified using the I2 value. Certainty of evidence was assessed using the GRADE Pro tool. Results One hundred and eleven articles were screened, 108 were excluded and three were k...
IntroductionIntraperitoneal dissemination is a major problem resulting in very poor prognosis and... more IntroductionIntraperitoneal dissemination is a major problem resulting in very poor prognosis and a rapid marked deterioration in the quality of life of patients. Pressurised intraperitoneal aerosol chemotherapy (PIPAC) is an emergent laparoscopic procedure aiming to maximise local efficacy and to reduce systemic side effects.Methods and analysisNab-PIPAC, a bicentre open-label phase IB, aims to evaluate safety of nab-paclitaxel and cisplatin association using in patients with peritoneal carcinomatosis (PC) of gastric, pancreatic or ovarian origin as ≥1 prior line of systemic therapy. Using a 3+3 design, sequential intraperitoneal laparoscopic application of nab-paclitaxel (7.5, 15, 25, 37.5, 52.5 and 70 mg/m2) and cisplatin (10.5 mg/m2) through a nebuliser to a high-pressure injector at ambient temperature with a maximal upstream pressure of 300 psi. Treatment maintained for 30 min at a pressure of 12 mm Hg and repeated4–6 weeks intervals for three courses total.A total of 6–36 pat...
BackgroundPatients undergoing colorectal surgery (CRS) have an increased risk of developing sexua... more BackgroundPatients undergoing colorectal surgery (CRS) have an increased risk of developing sexual disorders, attributed to different mechanisms. In this context, sexual function (SF) assessment of patients before and after surgery is essential: to identify risk factors for sexual disorders as well as to minimize their impact on overall quality of life (QoL), allowing them a satisfying relationship and sexual life.Material and methodsPatients over 18 years of age who underwent a CRS in the University Hospital of Geneva, Switzerland, between June 2014 and February 2016 were included. Our main objective was to compare and analyze the evolution of SF, QoL, and marital satisfaction (MS) before and after CRS. Specific and standardized tests were used.ResultsA cohort of 72 patients with a median age of 58.73 was analyzed. The majority of CRS was elective (91.5%). A percentage of 52.8% of patients underwent surgery for oncological reasons. There was no statistical difference in SF, sexual ...
Background Colon surgery has been shown to modulate the intestinal microbiota. Our objective was ... more Background Colon surgery has been shown to modulate the intestinal microbiota. Our objective was to characterize these changes using state-of-the-art next generation sequencing techniques. Methods We performed a single-centre prospective observational cohort study to evaluate the changes in the gut microbiota, i.e., taxon distribution, before and after elective oncologic colon surgery in adult patients with different antimicrobial prophylaxis regimens (standard prophylaxis with cefuroxime/metronidazole versus carbapenems for extended-spectrum beta-lactamase-producing Enterobacterales [ESBL-E] carriers). We obtained rectal samples on the day of surgery, intraoperative luminal samples, and rectal or stoma samples 3 days after surgery. We performed metataxonomic analysis based on sequencing of the bacterial 16S rRNA gene marker. Similarities and differences between bacterial communities were assessed using Bray–Curtis similarity, visualised using principal coordinates analysis and stat...
De Garengeot’s hernia is a rare entity in which the appendix is located within a femoral hernia a... more De Garengeot’s hernia is a rare entity in which the appendix is located within a femoral hernia and is almost invariably encountered incarcerated in an emergency setting. The clinical presentation is usually that of an incarcerated femoral hernia and is indistinguishable from other incarcerated femoral hernias. Here, we report on a 48-year-old female patient, known for a post-operative chronic seroma in the right groin since childhood, with a rare clinical presentation of a De Garengeot hernia. An abdominal CT-scan was performed, revealing an appendicitis with a stercolith in a femoral hernia. Generally, an inguinal approach alone (McVay procedure) is chosen and provides access for both appendectomy and hernia repair. In the absence of concomitant acute appendicitis, trans-abdominal pro-peritoneal laparoscopy (TAPP) could also be used as a single approach. In case of a rare presentation of acute appendicitis with probable contamination of the groin, we propose the double approach of...
Abstract Modulation of the microbiota of patients suffering from inflammatory bowel disease (IBD)... more Abstract Modulation of the microbiota of patients suffering from inflammatory bowel disease (IBD) with probiotics was suggested to avoid active disease and/or to lower the intensity of the active phase. Considering that the ecological niche of Bifidobacterium spp and Lactobacillus spp includes fermented dairy products, and that countries with highest dairy product consumption were those with lowest prevalence of IBD, we aimed at determining if consumption of dairy products could modulate the prevalence of IBD. Linear regression was performed on data from the Global Burden of Diseases, Injuries, and Risk Factors Study reporting the prevalence of IBD and from the European Association of Dairy Trade reporting national consumptions of dairy products. Consumption of milk, cheese or yoghourt per capita did not correlate with the prevalence of IBD at the national level in Western countries. Considering the limitations of this type of analysis, we recommend to continue investigating the effect of dairy product consumption on IBD by cross-sectional, longitudinal or interventional studies.
Resection of low rectal adenocarcinoma can be challenging in the narrow pelvis of male patients. ... more Resection of low rectal adenocarcinoma can be challenging in the narrow pelvis of male patients. Transanal total mesorectal excision (TaTME) appears to offer technical advantages for distal rectal tumours, and robotic-assisted transabdominal TME (rTME) was introduced in effort to improve operative precision and ergonomics. However, no study has comprehensively compared these approaches. The aim of the present study was to perform a systematic review of the literature to compare postoperative short-term outcomes in rTME and TaTME. A systematic online search (1974–July 2020) of MEDLINE, Embase, web of science and google scholar was conducted for trials, prospective or retrospective studies involving rTME, or TaTME for rectal cancer. Outcome variables included: hospital stay; operation duration, blood loss; resection margins; proportion of histologically complete resected specimens; lymph nodes; overall complications; anastomotic leak, and 30-day mortality. Sixty-two articles met the inclusion criteria, including 37 studies (3835 patients) assessing rTME resection, 23 studies (1326 patients) involving TaTME and 2 comparing both (165 patients). Operating time was longer in rTME (309.2 min, 95% CI 285.5–332.8) than in TaTME studies (256.2 min, 95% CI 231.5–280.9) (p = 0.002). rTME resected specimens had a larger distal resection margin (2.62 cm, 95% CI 2.35–2.88) than in TaTME studies (2.10 cm, 95% CI 1.83–2.36) (p = 0.007). Other outcome variables did not significantly differ between the two techniques. rTME provides similar pathological and short-term outcomes to TaTME and both are reasonable surgical approaches for patients with mid-to-low rectal cancer. To definitively answer the question of the optimal TME technique, we suggest a prospective trial comparing both techniques assessing long-term survival as a primary outcome.
AIM OF THE STUDY This European multicenter study aims to compare the results of laparoscopic vers... more AIM OF THE STUDY This European multicenter study aims to compare the results of laparoscopic versus laparotomy approach for the resection of splenic flexure colon carcinoma (SFC). PATIENTS AND METHODS Patients with SFC who required curative resection by laparoscopy (LAP) or laparotomy (OPEN) between 2000 and 2018 were included. Three types of interventions were considered: extended right hemi-colectomy, left hemi-colectomy and splenic flexure resection. The LAP and OPEN groups were matched according to propensity score and compared with Chi-square, Mann-Whitney tests, and multivariate regression models. Overall survival and recurrence-free survival were assessed using the Kaplan-Meier method. RESULTS The study population consisted of 399 patients, including 297 operated by LAP and 102 by OPEN. Extended right hemi-colectomy was performed in 35.8% of cases, left hemi-colectomy in 32.8% and splenic flexure resection in 31.4%. After propensity score matching, the LAP (n=64) and OPEN (n=64) groups were comparable for all pre-operative variables and tumor characteristics. The LAP group showed less blood loss and a shorter interval to return of transit and feeding compared to the OPEN group, regardless of the resection technique. There were no differences between the groups in terms of overall survival and 5-year recurrence-free survival. CONCLUSION These results support the application of laparoscopy for the resection of SFC.
Objective: The aim of this study was to determine the incidence of, and preoperative risk factors... more Objective: The aim of this study was to determine the incidence of, and preoperative risk factors for, positive circumferential resection margin (CRM) after transanal total mesorectal excision (TaTME). Background: TaTME has the potential to further reduce the rate of positive CRM for patients with low rectal cancer, thereby improving oncological outcome. Methods: A prospective registry-based study including all cases recorded on the international TaTME registry between July 2014 and January 2018 was performed. Endpoints were the incidence of, and predictive factors for, positive CRM. Univariate and multivariate logistic regressions were performed, and factors for positive CRM were then assessed by formulating a predictive model. Results: In total, 2653 patients undergoing TaTME for rectal cancer were included. The incidence of positive CRM was 107 (4.0%). In multivariate logistic regression analysis, a positive CRM after TaTME was significantly associated with tumors located up to 1...
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Papers by Frederic Ris