Operational effectiveness of three-dimensional flexible endoscopy: an ex vivo study using a new model Abstract Background and objectives Two-dimensional (2D) images lack depth information and thus provide probabilistic recognition that do not completely match the actual three-dimensional (3D) information. Here, we investigated the operability of 3D endoscopes. Methods A 3D operation model was developed by passing 20 silk threads through upper and lower plates at 2-mm intervals in front and back rows separated by 1 mm. We evaluated accuracy and time of operating an electrosurgical knife. A successful operation was defined as pulling only a front-row thread; an unsuccessful operation was defined as pulling no thread (miss) or simultaneously pulling front- and back-row threads. Endoscopists (four experts, six trainees) repeated the operation under 2D and 3D conditions until individually accumulating 10 successful attempts under each condition. Results Operation accuracy was significantly higher for 3D compared with 2D in all endoscopists (88.5% vs. 61.3%; p < 0.01) and in both experience groups (trainees: 84.5% vs. 61.2%; experts: 95.2% vs. 61.5%; both p < 0.01). Operation time was significantly shorter for 3D compared with 2D in all endoscopists (12.5 ± 4.1 s vs. 14.8 ± 4.7 s; p < 0.01) and in both experience groups (trainees: 12.8 ± 4.2 s vs. 15.2 ± 4.9 s; experts: 12.1 ± 4.0 s vs. 14.3 ± 4.3 s; both p < 0.01). Discussion Compared with 2D endoscopy, 3D endoscopy significantly improved operation accuracy and shortened operation time, suggesting that 3D endoscopy enables accurate operation by depth information, aiding spatial recognition.

The oncological and surgical safety of robot-assisted surgery in colorectal cancer: outcomes of a longitudinal prospective cohort study Abstract Background Colorectal cancer is one of the most common cancers worldwide. Laparoscopic colorectal surgery (LCRS) is a frequently used modality. A new development in minimally invasive surgery is robot-assisted colorectal surgery (RACRS). Methods Prospectively collected data of 378 consecutive patients who underwent RACRS or LCRS for stage I–III colorectal cancer from Dec 2014 to Oct 2017 were analyzed. Primary outcome was oncological outcome (radical margins, number of retrieved lymph nodes, locoregional recurrence). Secondary outcomes were distant metastases, overall and disease-free survival, operation time, conversion, length of hospital stay, and intra- and post-operative complications. Results 206 RACRS (129 colon and 77 rectal) and 172 LCRS (138 colon and 34 rectal) procedures were included. Baseline characteristics were similar. Overall median follow-up time was 15 months (0.2–36). Oncological outcome was similar. In colon cancer, radical margins were achieved in 99.3% in RACRS group versus 98.6% in LCRS group (p = 0.60), the average number of harvested lymph nodes was 16 ± 6 versus 18 ± 7 (p = 0.16), and locoregional recurrence rate in 24 months was 3.8% vs 3.8% (p = 0.99), respectively. In rectal cancer, radical margins were achieved in 89.6% in RACRS group versus 94.3% in LCRS group (p = 0.42), the average number of harvested lymph nodes was 16 ± 8 versus 15 ± 4 (p = 0.51), and locoregional recurrence rate in 24 months was 9.5 versus 5.6% (p = 0.42), respectively. Incidence of metastasis, survival rates, operation time, length of hospital stay, and number of severe post-operative complications measured by Clavien–Dindo scores did not differ between RACRS and LCRS groups. Conversion and intra-operative complication rates were significantly lower in the RACRS group as compared to the LCRS group (3% vs 9%, p = 0.008 and 2% vs 8%, p = 0.003, respectively). Conclusion RACRS is safe in the treatment of patients with stage I–III colorectal cancer. Oncological outcome did not differ between RACRS and LCRS groups. RACRS had lower conversion and intra-operative complication rates.

The learning curve in pure laparoscopic donor right hepatectomy: a cumulative sum analysis Abstract Background Although the use of pure laparoscopic donor hepatectomy (PLDH) is increasingly common, it remains limited to a few experienced centers and no data on the learning curve are currently available. The aim of this study is to evaluate the learning curve associated with the use of pure laparoscopic donor right hepatectomy (PLDRH). Methods Data from donors undergoing PLDRH performed by a single surgeon between November 2015 and October 2017 were retrospectively reviewed. The learning curve was evaluated using the cumulative sum (CUSUM) method based on duration of surgery. Results Of 100 donors evaluated, none required transfusion or conversion to open hepatectomy and no irreversible disability or mortality was reported. The mean operative time was 320.7 ± 51.8 min, and all grafts were successfully transplanted. The CUSUM analysis demonstrated a learning curve of approximately 60 cases of PLDRH. Estimated total liver volume > 1400 cm3 and double portal vein orifices were seen to be risk factors for longer surgery time. Having adjusted for case mix with these factors, the risk-adjusted CUSUM analysis demonstrated a learning curve of 65–70 cases of PLDRH. Conclusions In conclusion, PLDRH is a feasible and safe procedure with a learning curve of 65–70 cases.

The impact of robotic colorectal surgery in obese patients: a systematic review, meta-analysis, and meta-regression Abstract Background Robotic surgery (RS) may overcome the limitations of laparoscopic colorectal surgeries (LS) in obese patients, but remains less well studied. This systematic review and meta-analysis aims to evaluate the outcomes of obese patients who have undergone robotic colorectal surgery. Methods This study was performed according to the PRISMA guidelines. A search was performed on Medline, EMBASE, and the Cochrane Library to identify relevant articles. Dichotomous and continuous outcomes were analyzed as risk ratio (RR) and mean difference (MD), respectively. All post-operative outcomes were within 30 days after surgery. The quality of studies was assessed using the Newcastle–Ottawa Scale. Meta-regression analysis was conducted to identify sources of heterogeneity. Results Three studies totaling 262 subjects compared LS (45.0%) against RS (55.0%) in obese patients. The RS group had a significantly reduced length of hospital stay (LOS) (MD − 2.55 days, 95%CI − 3.13 to − 1.97 days, P < 0.00001, I2 = 26%) and lower risk of re-admission (RR 0.42, 95%CI 0.19–0.92, P = 0.030, I2 = 0%), however, the length of operative time was longer (MD 40.54 min, 95%CI 32.72–48.36 min, P < 0.00001, I2 = 37%). Six studies totaling 761 subjects compared obese (40.5%) against non-obese (59.5%) patients who underwent RS. An increased operative time (MD 20.72 min, 95%CI 7.39–34.04 min, P = 0.002, I2 = 0%) and risk of wound infection (RR 2.59, 95%CI 1.12–6.02, P = 0.030, I2 = 0%) were noted in the former, with no differences in other intra- and post-operative outcomes. Meta-regression revealed that the pathology (rectal, colon, both) (P = 0.255), age (P = 0.530), gender (P = 0.279), and continent that the study originated from (P = 0.583) were not significant sources of heterogeneity for the risk of wound infection. Conclusion Compared to laparoscopy, robotic surgery provides earlier recovery with shorter LOS and reduced re-admission rates for obese patients, without compromising on other operative outcomes. Among patients undergoing robotic colorectal surgery, obesity is associated with a longer operative duration and greater risk of wound infection.

Enabling single-site laparoscopy: the SPORT platform Abstract Background The Single Port Orifice Robotic Technology (SPORT) Surgical System by Titan Medical Inc. is designed to overcome the inherent challenges of minimally invasive single-access procedures. The aim of this preclinical study was to evaluate the feasibility of various digestive surgery procedures using this novel surgical robotic platform. Methods A total of 12 minimally invasive procedures were performed on six pigs (5 cholecystectomies, 3 Nissen fundoplications, 1 splenectomy and 1 hepatic pedicle dissection) and on one human cadaver (1 cholecystectomy and 1 Nissen fundoplication), by four laparoscopic surgeons. The usability of the device was assessed by means of the modified objective structured assessment of technical skills (OSATS) score that was calculated and analyzed by two independent observers on the recorded videos. Surgeon feedback and recommendations were systematically recorded. Results All procedures were successfully completed with the SPORT system. In general, surgeons reported to appreciate the intuitive interface and controls, the high-resolution 3D imaging, the dexterity of the end-effectors, and the ergonomic open control platform. Some features requiring optimization were also identified. The modified OSATS score demonstrated a learning curve effect for all device-related tasks. Conclusions A variety of abdominal procedures could be safely completed with the current SPORT prototype, in the preclinical setting. This preliminary feasibility experience is promising and encourages further development of single-port robotically assisted surgery.

Long-term clinical outcomes of endoscopic vs. surgical resection for early gastric cancer with undifferentiated histology Abstract Background The efficacy of endoscopic submucosal dissection (ESD) for undifferentiated early gastric cancer (UD EGC) is controversial due to the relatively high risk of lymph node metastasis. We compared long-term clinical outcomes of UD EGC between ESD and surgical resection groups. Methods We retrospectively reviewed the medical records of patients with UD EGC treated by either ESD or surgical resection between January 2007 and December 2014. Long-term clinical outcomes were compared between the two groups in terms of survival. Results A total of 1147 patients were enrolled with median follow-up duration of 59.1 months. ESD and surgical resections were performed in 126 and 1021 patients respectively. Additional surgery was performed in 22 patients after ESD. There were no significant differences in overall survival [total, p = 0.641; propensity score matching (PSM), p = 0.330; expanded criteria, p = 0.512]. Although the disease-free survival rate was lower in ESD group because of the higher rate of metachronous cancer development (total, p < 0.001; PSM, p = 0.001), the difference was not significant in the group within expanded criteria (p = 0.071). Conclusions ESD could be a comparable treatment option with surgical resection for UD EGC within expanded criteria in terms of long-term survival. It is mandatory to establish a meticulous indication of ESD for UD EGC considering the risk of lymph node metastasis.

Evaluation of hyperspectral imaging (HSI) for the measurement of ischemic conditioning effects of the gastric conduit during esophagectomy Abstract Background Hyperspectral imaging (HSI) is a relatively new method used in image-guided and precision surgery, which has shown promising results for characterization of tissues and assessment of physiologic tissue parameters. Previous methods used for analysis of preconditioning concepts in patients and animal models have shown several limitations of application. The aim of this study was to evaluate HSI for the measurement of ischemic conditioning effects during esophagectomy. Methods Intraoperative hyperspectral images of the gastric tube through the mini-thoracotomy were recorded from n = 22 patients, 14 of whom underwent laparoscopic gastrolysis and ischemic conditioning of the stomach with two-step transthoracic esophagectomy and gastric pull-up with intrathoracic anastomosis after 3–7 days. The tip of the gastric tube (later esophagogastric anastomosis) was measured with HSI. Analysis software provides a RGB image and 4 false color images representing physiologic parameters of the recorded tissue area intraoperatively. These parameters contain tissue oxygenation (StO2), perfusion—(NIR Perfusion Index), organ hemoglobin (OHI), and tissue water index (TWI). Results Intraoperative HSI of the gastric conduit was possible in all patients and did not prolong the regular operative procedure due to its quick applicability. In particular, the tissue oxygenation of the gastric conduit was significantly higher in patients who underwent ischemic conditioning ( \({\overline {{{\text{St}}{{\text{O}}_2}}} _{_{{{\text{Precond}}.}}}}\)  = 78%; \({\overline {{{\text{St}}{{\text{O}}_2}}} _{_{{{\text{NoPrecond}}.}}}}\)  = 66%; p = 0.03). Conclusions HSI is suitable for contact-free, non-invasive, and intraoperative evaluation of physiological tissue parameters within gastric conduits. Therefore, HSI is a valuable method for evaluating ischemic conditioning effects and may contribute to reduce anastomotic complications. Additional studies are needed to establish normal values and thresholds of the presented parameters for the gastric conduit anastomotic site.

After laparoscopic liver resection for colorectal liver metastases, age does not influence morbi-mortality Abstract Background Hepatectomy remains the only curative option in patients presenting with colorectal liver metastases (CLM). Although laparoscopic approach has improved postoperative morbidity and mortality rates, its suitability for patients of all age groups has yet to be confirmed. The aim of this study was to analyze postoperative outcomes following laparoscopic liver resection (LLR) in different age groups of patients presenting with CLM. Methods All patients who underwent LLR for CLM from 2008 to 2017 were reviewed. Patients were divided into four age groups: < 55, 55–65 years, 65–75 and > 75 years. Baseline and intraoperative characteristics as well as postoperative morbidity and mortality were compared between all four groups. Results Overall, 335 patients were included with 34 (10%), 113 (34%), 136 (41%) and 52 (15%) in < 55, 55–65, 65–75 and > 75 years subgroups. Baseline characteristics were similar between all four groups except for elevated pressure, dyslipidemia and ASA score which were higher in older patients. Regarding surgical procedures, major hepatectomy, uni- or bisegmentectomy and wedge resection were performed in 122 (36%), 87 (26%) and 126 (38%) patients, respectively, with no significant differences between age groups. Overall, 90-day postoperative mortality rate was nil and postoperative morbidity was similar between all four groups except for biliary fistula occurrence, which was higher in < 55 years patients (p = 0.006). Conclusion Short-term postoperative outcome following LLR for CLM does not seem to be affected by age. Curative laparoscopic treatment should therefore be considered whenever possible, regardless of patient age.

Endoscopic full-thickness resection (EFTR) without laparoscopic assistance for nonampullary duodenal subepithelial lesions: our clinical experience of 32 cases Abstract Background Standard treatment for nonampullary duodenal tumors has not yet been established. In case of tumors originated from the muscularis propria (MP) layer and adherent to the serosa layer, the lesions can not be completely removed by ESD. However, with the development of the endoscopic suture technique, endoscopic full-thickness resection (EFTR) of duodenal subepithelial lesions has become possible. Methods We retrospectively analyzed 32 patients with nonampullary duodenal subepithelial lesions who underwent EFTR between February 2012 and January 2017. The suturing method, complications that occurred during and after the operations, perioperative management, tumor characteristics, and pathological findings were analyzed in all patients. Results The complete resection rate was 100%; all patients successfully received EFTR except for one patient who required conversion to open surgery. Severe abdominal pain was observed after the operation in one patient who then received laparoscopic exploration, and the possibility of delayed perforation was considered. Another patient showed a decline in blood oxygen saturation (SO2) and was transferred to the intensive care unit (ICU) for further management. Delayed bleeding and fistula were not observed. All patients achieved complete remission. Conclusion EFTR is a safe, minimally invasive treatment modality that ensures complete eradication of the duodenal subepithelial lesions.

The efficacy of dental floss and a hemoclip as a traction method for the endoscopic full-thickness resection of submucosal tumors in the gastric fundus Abstract Background Endoscopic full-thickness resection (EFTR) provides a significant advancement to the treatment of gastrointestinal submucosal tumors (SMTs). However, technological challenges, particularly in the gastric fundus, hinder its wider application. Here, we investigated the efficacy of a simple traction method that used dental floss and a hemoclip (DFC) to facilitate EFTR. Methods Between July 2014 and December 2016, we retrospectively reviewed data from all patients with SMTs in the gastric fundus originating from the muscularis propria layer that were treated by EFTR at Zhongshan Hospital of Fudan University. Baseline characteristics and clinical outcomes, including procedure time and complications rate, were compared between groups of patients receiving DFC–EFTR and conventional EFTR. Results A total of 192 patients were included in our analysis (64 in the DFC–EFTR group and 128 in the conventional EFTR group). Baseline characteristics for the two groups were similar. The mean time for DFC–EFTR and conventional EFTR was 44.2 ± 24.4 and 54.2 ± 33.2 min, respectively (P = 0.034). Although no serious adverse events presented in any of our cases, post-EFTR electrocoagulation syndrome (PEECS), as a minor complication, was less frequent in the DFC–EFTR group (3.1% vs. 12.5%, P = 0.036). Univariate and multivariate analysis identified that DFC, when used in EFTR, played a significant role in reducing procedure time and the rate of PEECS. The mean procedure time was significantly shorter in the DFC–EFTR group for lesions over 1.0 cm (P = 0.005), when the lesions were located in the greater curvature of the gastric fundus (P = 0.025) or when the lesions presented with intraluminal growth (P = 0.032). Moreover, when EFTR was carried out by experts, the mean procedure time was 20.4% shorter in the DFC–EFTR group (P = 0.038). Conclusions This study indicated that DFC–EFTR for SMTs in the gastric fundus resulted in a shorter procedure time and reduced the risk of PEECS, a minor complication.