Autonomous and intercellular chemokine signaling elicited from mesenchymal stem cells regulates migration of undifferentiated gastric cancer cells.

Accumulating evidence demonstrates that bone marrow (BM)-derived mesenchymal stem cells (MSCs) play critical roles in regulating progression of various types of cancer. We have previously shown that Wnt5a-Ror2 signaling in MSCs induces expression of CXCL16, and that CXCL16 secreted from MSCs then binds to its cognate receptor CXCR6 on the surface of an undifferentiated gastric cancer cell line MKN45 cells, eventually leading to proliferation and migration of MKN45 cells. However, it remains unclear about a possible involvement of another (other) cytokine(s) in regulating progression of gastric cancer. Here, we show that CXCL16-CXCR6 signaling is also activated in MSCs through cell-autonomous machinery, leading to upregulated expression of CCL5. We further show that CCR1 and CCR3, receptors of CCL5, are expressed on the surface of MKN45 cells, and that CCL5 secreted from MSCs promotes migration of MKN45 cells presumably via its binding to CCR1/CCR3. These data indicate that cell-autonomous CXCL16-CXCR6 signaling activated in MSCs upregulates expression of CCL5, and that subsequent activation of CCL5-CCR1/3 signaling in MKN45 cells through intercellular machinery can promote migration of MKN45 cells. Collectively, these findings postulate the presence of orchestrated chemokine signaling emanated from MSCs to regulate progression of undifferentiated gastric cancer cells.

Laparoscopic creation of a retrosternal route for gastric conduit reconstruction.

BACKGROUND: Retrosternal reconstruction is associated with a lower risk of mediastinitis, gastro-tracheal fistula, and hiatal hernia. Historically, traumatic manual creation of the retrosternal tunnel has been performed using one's fist. We report a novel and atraumatic laparoscopic procedure to create the retrosternal route. METHODS: We have laparoscopically created the retrosternal route in 25 thoracoscopic, mediastinoscopic, or robot-assisted minimally invasive esophagectomies since August 2019. Specifically, a peritoneal incision is started at the dorsal side of the xiphoid process. Through a 12-mm port inserted slightly to the right of and superior to the umbilical camera port, we dissect loose connective tissues from the caudal to the cranial side using behind the sternum and inside the internal thoracic vessels as landmarks. The time required to create the route was calculated. Then, the cumulative sum (CUSUM) method and the simple moving average of five cases were used to evaluate the learning curve of this novel procedure. Operative outcomes were analyzed according to the learning curve results and also compared with 25 cases of postmediastinal reconstruction counterparts. RESULTS: Twenty-five patients were divided into the early group (six patients) and late group (19 patients) based on the peak of the CUSUM chart. The time required for route creation was 28.5 min (median) in the early and 15 min in the late group, indicating a significant difference (P = 0.038). The overall incidence of pleural injury was 20% (5 of 25 patients), with no significant difference between the groups. There was no significant difference in the incidence of perioperative complications. Also, there were no significant differences in perioperative complications or gastric conduit functions 1 year after surgery between the retrosternal and the postmediastinal reconstruction. CONCLUSION: Laparoscopic creation of a retrosternal route for gastric conduit reconstruction is safe and feasible and has a short learning curve.

Comparison of laparoscopic gastrectomy with 3-D/HD and 2-D/4 K camera system for gastric cancer: a prospective randomized control study.

PURPOSE: We conducted a prospective clinical control study to identify the best imaging technology among three-dimensional (3-D) high-definition (HD) stereovision and two-dimensional (2-D) ultra-high-resolution (4 K) technology and confirm their effects on surgical outcomes of laparoscopic gastrectomy for gastric cancer. METHODS: From April 2018 to August 2019, 50 patients were randomly classified into two groups based on the imaging technology (3-D/HD group = 25, 2-D/4 K = 25). After excluding eight patients based on laparoscopic findings, 42 patients were analyzed (3-D/HD group = 21, 2-D/4 K = 21). The primary endpoint was the operative time; the secondary endpoints were blood loss, postoperative infectious complications, and postoperative hospital stay. RESULTS: The patients' backgrounds were similar (sex, age, body mass index [BMI], stage, procedure, and extent of lymph node dissection). There were no significant differences in operative time (252 vs. 238 min, P = 0.70), total blood loss, postoperative infectious complications, and postoperative hospital stay between the two groups. However, video analysis of surgeries revealed a significantly shortened median operative time (18 vs. 25 min, P = 0.04) in the suturing step with 3-D/HD; the median number of camera cleaning procedures during suprapancreatic lymph node dissection was significantly lower with 2-D/4 K than with 3-D/HD (n = 4.4 vs. 2.8, P = 0.02). CONCLUSION: 3-D/HD and 2-D/4 K laparoscopic radical gastrectomies provide similar surgical outcomes. However, the 3-D monitor reduces suturing time during reconstruction, while the 4 K monitor reduces the number of camera cleaning procedures during lymphadenectomy. TRIAL REGISTRATION: Registered in the University Hospital Medical Information Network Clinical Trials Registry (identification number 000029227).

Quantitative Comparison of Surgical Device Usage in Laparoscopic Gastrectomy Between Surgeons' Skill Levels: an Automated Analysis Using a Neural Network.

BACKGROUND: Whether surgical device usage in laparoscopic gastrectomy differs with respect to operator's skill levels is unknown. Further, device usage analysis using artificial intelligence has not been reported to date. Herein, we compared the patterns of surgical device usage during laparoscopic gastrectomy for gastric cancer among surgeons at different skill levels. The data of device usage was acquired from laparoscopic video recordings using an automated surgical-instrument detection system. METHODS: In total, 100 video recordings of infrapyloric lymphadenectomy and 33 of D2 suprapancreatic lymphadenectomy during laparoscopic gastrectomy for gastric cancer were analyzed in this retrospective study. The system's accuracy was evaluated by comparing the automatic and the manual usage time. Surgical device usage patterns were compared between qualified and nonqualified surgeons of The Japan Society for Endoscopic Surgery Endoscopic Surgical Skill Qualification System. RESULTS: For every device, the automatic detection time and manual detection time were consistent with each other. In infrapyloric lymphadenectomy, the usage time proportions of dissector forceps and clip applier were higher among nonqualified operators than among qualified operators (dissector, 5.1% vs. 2.3%, P < 0.001; clip applier, 1.6% vs. 1.3%, P < 0.01). In suprapancreatic lymphadenectomy, the usage time proportions of energy devices, clip applier, and grasper forceps were significantly different (energy devices, 59.6% vs. 50.6%, P < 0.001; clip applier, 1.4% vs. 0.9%, P < 0.001; only grasper forceps; 18.3% vs. 27.9%, P = 0.022). CONCLUSIONS: Quantitative analysis of laparoscopic device usage using the automated surgical device detection system showed that the patterns of device usage during laparoscopic gastrectomy differed depending on surgeons' skill levels. These differences could suggest how the qualified and nonqualified surgeons performed the procedures.

Impact of chronic kidney disease stage on morbidity after gastrectomy for gastric cancer.

AIM: The outcomes of gastrectomy for gastric cancer in patients at each severity of chronic kidney disease (CKD) remain unknown. METHODS: We retrospectively analyzed the outcomes of 560 patients who underwent distal or total gastrectomy for gastric cancer between 2009 and 2018. We classified the patients into four groups based on estimated glomerular filtration rate: stage 1/2 (normal to mild, n = 375), stage 3a (mild to moderate, n = 122), stage 3b (moderate to severe, n = 43), and stage 4/5 (severe to end-stage, n = 20) CKD. The relationship between CKD stage and the incidence of postoperative morbidity was analyzed. RESULTS: CKD was a predictor of overall morbidity independent of age, gender, American Society of Anesthesiologists Performance Status, pulmonary comorbidity, extent of lymphadenectomy, and operation time in a multivariate analysis. The incidences of overall and severe morbidity were significantly increased with CKD progression (both P < .001). Compared to stage 1/2 CKD, the odds of overall morbidity were significantly elevated in stage 3a (odds ratio [OR] 1.87, P = .007), stage 3b (OR 3.86, P < .001), and stage 4/5 (OR 8.60, P < .001). The risk of procedure-related morbidity was strikingly increased in stage 3b (OR 2.93, P = .004). The risk of procedure-unrelated morbidity elevated markedly in stage 3a (OR 2.77, P = .001). A significant graded association between CKD progression and overall morbidity was also revealed in elderly patients (P = .001). CONCLUSIONS: The severity of CKD predicts the likelihood and type of morbidity after gastrectomy and can guide surgical decision-making for patients with gastric cancer.

Simple Cancer Stem Cell Markers Predict Neoadjuvant Chemotherapy Resistance of Esophageal Squamous Cell Carcinoma.

BACKGROUND/AIM: Cancer stem cells (CSCs) contribute to resistance against neoadjuvant chemotherapy (NAC) in esophageal squamous cell carcinoma (ESCC). We conducted a retrospective observational study for the relationship between the expression levels of CSC markers in biopsy specimens prior to 5-fluorouracil plus cisplatin (FP)-NAC and the pathological responses. PATIENTS AND METHODS: We included 171 patients with ESCC who underwent the FP-NAC followed by radical resection. Biopsy specimens prior to the FP-NAC were obtained and immunochemically stained for CD44, CD133, and CD24. RESULTS: The biopsy specimens of the non-responders had the CD44high/CD24low expression at high levels, which was found as an independent predictor of not only FP-NAC resistance but also poor overall survival by multivariate analyses. CONCLUSION: CD44high/CD24low expression in the biopsy specimens prior to FP-NAC may be a predictor of FP-NAC resistance and poor prognosis of ESCC patients.

Transperineal minimally invasive abdominoperineal resection for low rectal cancer: standardized technique and clinical outcomes.

BACKGROUND: Despite the increasing utilization of transanal total mesorectal excision as a promising approach for low rectal cancer, the feasibility and safety of transperineal minimally invasive abdominoperineal resection (tp-APR) remain unclear. METHODS: In total, 25 patients who underwent tp-APR between April 2017 and May 2020 (tp-APR group) and 27 patients who underwent conventional laparoscopic APR between May 2009 and September 2016 (lap-APR group) for low rectal cancer were enrolled in this retrospective study. Clinical outcomes were compared between the groups before and after propensity score matching. The primary outcome was the incidence of the overall postoperative complications with Clavien-Dindo grade II or above. Standardized technique of tp-APR was also demonstrated. RESULTS: On comparison, operative time, intraoperative blood loss, and overall postoperative complications with Clavien-Dindo grade II or above were significantly less in the tp-APR group both before and after propensity score matching. The rates of urinary disturbance and perineal wound infection were significantly less in the tp-APR group after matching. Further, postoperative hospital stay was significantly shorter in the tp-APR group both before and after matching. However, pathological outcomes did not differ between the groups before and after matching. There has been no local recurrence in the tp-APR group with a median follow-up period of 18 months. CONCLUSION: Standardized tp-APR for low rectal cancer is feasible and seems superior to conventional laparoscopic APR in terms of short-term outcomes. Further larger-scale studies with a longer follow-up period are required to evaluate oncological outcomes.

Feasibility and Safety of Lateral Pelvic Lymph Node Dissection After Neoadjuvant Chemoradiotherapy for Elderly Patients With Locally Advanced Rectal Cancer.

BACKGROUND/AIM: The safety of neoadjuvant chemoradiotherapy (NACRT) combined with total mesorectal excision (TME) and selective lateral pelvic lymph node dissection (LLND) is unclear in elderly patients with locally advanced rectal cancer (LARC). PATIENTS AND METHODS: Forty-two patients with LARC underwent TME and selective LLND following NACRT at Kobe University Hospital. The clinical outcomes were retrospectively compared between the elderly (aged ≥70 years, n=13) and non-elderly patients (aged <70, n=29). RESULTS: Twelve of the thirteen elderly patients could complete NACRT. Although the overall rate of postoperative complications did not differ between the groups, abdominal wound infection and deep vein thrombosis developed more frequently in the elderly group. The length of the postoperative hospital stay was similar. Three-year overall survival and 3-year relapse-free survival rates were similar between the groups. CONCLUSION: Selective LLND after NACRT is safe for elderly patients with LARC.

Novel "Modified Bascule Method" for Lymphadenectomy Along the Left Recurrent Laryngeal Nerve During Robot-Assisted Minimally Invasive Esophagectomy.

BACKGROUND: Given the worldwide popularization of conventional minimally invasive esophagectomy (C-MIE), robot-assisted MIE (RAMIE) can be expected to provide a finer procedure. However, controversy remains regarding whether RAMIE is superior to C-MIE in preventing recurrent laryngeal nerve (RLN) palsy. Considering the shallow learning curve for RAMIE, a novel procedure for lymphadenectomy along the RLN during RAMIE is needed. METHODS: Based on a logical and simple understanding of the left upper mediastinum anatomy, the authors developed a novel "modified bascule method" for RAMIE that could simplify lymphadenectomy along the left RLN and prevent it from being touched and stretched. Between 2018 and 2020, 46 patients with esophageal carcinoma underwent RAMIE using this method at Kobe University. RESULTS: The modified bascule method was used to perform RAMIE for 29 men and 17 women with a median age of 67 years (range, 49-82 years). The median thoracoscopic procedure time was 438 min (range, 344-625 min), and the median console time was 351 min (range 273-518 min). The study harvested a median of 24 (range, 8-34) lymph nodes from the thoracic portion and 4 (range, 0-10) lymph nodes from along the left RLN. The mortality rate was 0%. Postoperative left RLN palsy classified as Clavien-Dindo (C-D) grade 1 or higher was observed for 9 patients (19%), whereas grade 2 or higher was not seen (0%). Pneumonia and anastomotic leakage rates higher than C-D grade 2 were respectively 13% and 19%. CONCLUSIONS: The novel modified bascule method for RAMIE can promote feasible lymphadenectomy along the left RLN even when performed during the learning period.

Impact of Lymph Node Ratio on Survival Outcome in Esophageal Squamous Cell Carcinoma After Minimally Invasive Esophagectomy.

BACKGROUND: Esophageal squamous cell cancer (ESCC) is one of the deadliest cancers in the world. Esophagectomy remains the principal treatment, and minimally invasive esophagectomy (MIE) has been performed worldwide. This study aimed to clarify whether the lymph node ratio (LNR), defined as the ratio of metastatic lymph nodes (LNs) to examined, is a prognostic factor for ESCC after MIE. METHODS: This study included 327 MIEs with the patient in the prone position at two institutions from 2010 to 2015. Cox proportional hazards regression analyses using clinicopathologic characteristics and the LNR were performed for the pN1 patients and the whole cohort. RESULTS: In the multivariate analysis for all stages, independent prognostic factors were depth of tumor invasion (P < 0.0001), LNR (P = 0.014), operative time (P = 0.003), and pneumonia (P = 0.012). In the analysis of the pN1 subgroup, the optimum LNR cutoff level for overall survival (OS) was 9 based on receiver operation characteristic analysis. The LNR was significantly associated with depth of tumor invasion (P = 0.004) and number of metastatic LNs (P < 0.0001). The OS curve for the group with an LNR of 9 or higher was significantly worse than for the group with an LNR lower than 9 (P < 0.001). Multivariate analyses demonstrated that the LNR is a unique independent prognostic factor for the pN1 subgroup (hazard ratio, 6.811; 95% confidence interval, 2.009-23.087; P = 0.002). CONCLUSIONS: The LNR is an independent prognostic factor in ESCC after MIE. Especially for patients with pN1 status, the LNR is more useful than the number of metastatic LNs for predicting survival outcome.

Three-dimensional visualization system is one of the factors that improve short-term outcomes after minimally invasive esophagectomy.

PURPOSE: Minimally invasive esophagectomy (MIE) has been increasingly used, but many reports have stated that recurrent laryngeal nerve (RLN) palsy after MIE is a major complication associated with postoperative pneumonia. Prevention of RLN palsy clearly has been a challenging task. The study aim was to determine if a three-dimensional (3-D) stereoscopic vision system can reduce the RLN palsy rate after MIE. METHODS: This was a retrospective study of MIE (McKeown esophagectomy) using a 3-D or 2-D stereoscopic vision system to treat 358 patients in the prone position between April 2010 and March 2019. The patients who underwent 3-D MIE (3-D group) or 2-D MIE (2-D group) were matched by using propensity score matching. After matching, the perioperative outcomes were compared between the groups. RESULTS: After propensity score matching, 154 patients were analyzed (77 patients, 3-D group; 77 patients, 2-D group). There were no significant differences in the patients' baseline characteristics in the matched cohort. There were no significant differences in the rates of pneumonia (Clavien-Dindo (C-D) grade ≥ II, 3-D vs. 2-D, 11 (14%) vs. 12 (16%)), anastomotic leakage (C-D grade ≥ II, 10 (13%) vs. 18 (23%)) and mortality. The rates of left RLN palsy (C-D grade ≥ IIIa, 1 (1.3%) vs. 7 (9.1%), P = 0.029), right RLN palsy (C-D grade ≥ I, 2 (3%) vs. 8 (10%), P = 0.049), comprehensive complication index (CCI®) (8.5 vs. 14.3, P = 0.011), and postoperative hospital stay period (median: 25 vs. 30 days, P = 0.034) were significantly lower in the 3-D group than in the 2-D group, respectively. CONCLUSIONS: In MIE, the 3-D viewing system was one of the factors that reduced postoperative morbidities such as the rates of each RLN palsy and CCI®, leading to shorter postoperative hospital stay.

Postoperative recurrent laryngeal nerve palsy is associated with pneumonia in minimally invasive esophagectomy for esophageal cancer.

BACKGROUND: During the past decade, minimally invasive esophagectomy (MIE) for esophageal cancer has been adopted worldwide with expectations of lower invasiveness. However, the rate of postoperative pneumonia, which is an independent risk factor for oncological prognosis in esophageal cancer, remains high. The aim of this retrospective follow-up study is to clarify whether there is a strong correlation between recurrent laryngeal nerve (RLN) palsy and postoperative pneumonia in MIE. METHODS: This retrospective follow-up study included 209 patients with esophageal cancer who underwent thoracoscopic esophagectomy in the prone position (TEP) at Kobe University between 2011 and 2018. Inclusion criteria included age 18-85 years; cT1-3, cN0-3 disease; upper mediastinal lymphadenectomy; and ability to undergo simultaneous esophagectomy and reconstruction of the gastric conduit or pedicled jejunum. Univariate and multivariate logistic regression were conducted to identify independent risk factors for pneumonia. RESULTS: Among 209 TEPs, pneumonia of Clavien-Dindo classification grade > II occurred in 44 patients (21%). In the pneumonia positive and negative groups, there were significant differences in age (67.9 ± 7.5 vs. 64.9 ± 8.6 years), 3-field lymph node dissection [27 (61%) vs. 67 (41%)], transfusion [20 (45%) vs. 41 (25%)], left RLN palsy [19 (43%) vs. 18 (11%)], and any RLN palsy [20 (45%) vs. 18 (11%)]. In multivariate analysis, any RLN palsy was associated with a higher incidence of pneumonia [odds ratio (OR), 6.210; 95% confidence interval (CI), 2.728-14.480; P < 0.0001]. In addition, age was associated with a higher incidence of pneumonia (OR, 1.049; 95% CI, 1.001-1.103; P = 0.046). Changes in the rate of any RLN palsy over time were quite similar to changes in the incidence of pneumonia. CONCLUSION: There is a strong correlation between RLN palsy and pneumonia in MIE for esophageal cancer. Prevention of RLN palsy may reduce the incidence of pneumonia, leading to better oncological prognosis.

Multimodality approaches to control esophageal cancer: development of chemoradiotherapy, chemotherapy, and immunotherapy.

Esophageal cancer has a poor prognosis despite the fact that surgical techniques have been advanced and optimized, and systemic multimodality approaches have progressed recently. Adding chemotherapy, radiotherapy, and immunotherapy to the basic surgical approach have been shown to have therapeutic benefit for esophageal cancer. This review describes the latest development of chemoradiotherapy, chemotherapy, and immunotherapy, which have contributed to the reduction in esophageal cancer growth and improved the survival of patients. Chemoradiation is a treatment option for resectable esophageal cancer to preserve the esophagus for patients who cannot tolerate surgery. Moreover, a combination of chemoradiotherapy and salvage surgery could extend the survival of patients. The effects of a triplet chemotherapy regimen are currently being verified in some Phase III studies for unresectable advanced/recurrent esophageal cancer. In addition, with the great promise of immune checkpoint inhibitors, strategies that incorporate the use of immunotherapy may shift from the metastatic setting to the neoadjuvant/adjuvant setting as a result of clinical trials. More precise comprehension of the molecular biology of esophageal cancer is expected to further control disease progression using multimodality treatments in the future.

Survival Benefit of Neoadjuvant Chemotherapy for Locally Advanced Adenocarcinoma of Esophagogastric Junction.

Background/Aim: Adenocarcinoma of the esophagogastric junction (AEG) is refractory even when curative resection is followed by adjuvant chemotherapy. This study evaluated the efficacy of neoadjuvant chemotherapy (NAC) using an oral fluoropyrimidine-platinum regimen for AEG. Patients and Methods: Out of 35 patients with locally advanced AEG who underwent curative resection, 21 who underwent surgery first and 14 who received NAC were retrospectively compared in terms of survival. Results: The NAC regimens comprised of S-1 or capecitabine plus oxaliplatin or cisplatin; trastuzumab was added to six borderline resectable cases. The downstaging rate was 50% and the pathological response rate including complete response (29%) was 50%. The three-year relapse-free survival in the NAC group was significantly superior than the surgery-first group (78% vs. 22%, p=0.011). The NAC group had a significantly longer median survival time than the surgery-first group (NR vs. 29 months, p=0.032). Conclusion: NAC using an oral fluoropyrimidine-platinum regimen may provide survival benefit in AEG.

Preoperative endoscopic tattooing using India ink to determine the resection margins during totally laparoscopic distal gastrectomy for gastric cancer.

PURPOSE: This study was conducted to determine whether establishing the proximal resection line using India ink tattooing can ensure safe resection margins during totally laparoscopic distal gastrectomy. METHODS: This retrospective study included 81 patients who underwent totally laparoscopic distal gastrectomy for gastric cancer on the lower two-thirds of the stomach. The proximal resection margins were analyzed with respect to the macroscopic type and clinical T stage, and the intraoperative appearance of the stain on the serosa was classified by reviewing surgical videos. RESULTS: R0 resection was performed in all patients. The rates of the intended margins were 89.2% in patients without a frozen section diagnosis and 84.2% in patients with differentiated type lesions who underwent a frozen section diagnosis; however, most patients with undifferentiated advanced lesions failed to achieve the intended resection margins. Intraoperative appearance revealed that 85.2% of patients had localized type stains, whereas 11.1% had widespread-type stains. CONCLUSIONS: Our procedure to determine the proximal resection line in totally laparoscopic distal gastrectomy is oncologically safe. However, careful observation of the resected specimen and a frozen section analysis should be performed for undifferentiated advanced lesions.

Severe weight loss after minimally invasive oesophagectomy is associated with poor survival in patients with oesophageal cancer at 5 years.

BACKGROUND: Patients often experience severe weight loss after oesophagectomy. Enteral nutrition via a feeding jejunostomy tube (FT) is commonly practised. This study aimed to assess the effect of severe weight loss postoperatively and enteral nutrition via an FT on long-term prognosis after oesophagectomy. METHODS: This study analysed 317 patients who underwent minimally invasive oesophagectomy at Kobe University Hospital and Hyogo Cancer Center from 2010 to 2015. The patients' body weight was evaluated at 3 months postoperatively. They were organised into the severe weight loss (n = 65) and moderate weight loss (n = 252) groups. Furthermore, they were categorised into the FT group (184 patients who had an FT placed during oesophagectomy) and no-FT group (133 patients without FT). Patients (119 per group) matched for the FT and no-FT groups were identified via propensity score matching. RESULTS: The 5-year overall survival (OS) rate in the severe weight loss group was significantly lower (p = 0.024). In the multivariate analysis, tumour invasion depth (pT3-4), preoperative therapy and severe weight loss had a worse OS (hazard ratio = 1.89; 95% confidence interval = 1.12-3.17, hazard ratio = 2.11; 95% confidence interval = 1.25-3.54, hazard ratio = 1.82; 95% confidence interval = 1.02-3.524, respectively). No significant differences in the number of severe weight loss patients and OS were found between the FT and no-FT groups. CONCLUSION: Severe weight loss is significantly associated with poor OS. In addition, enteral nutrition via an FT did not improve the severe weight loss and OS.

Significance of prediction of the dorsal landmark using three-dimensional computed tomography during laparoscopic lymph node dissection along the proximal splenic artery in gastric cancer.

OBJECTIVES: Dissection of the No. 11p lymph nodes is technically challenging because of variations in anatomical landmarks. This study aimed to determine the accuracy and efficacy of predicting the dorsal landmark of No. 11p lymph node using three-dimensional computed tomography simulation. METHODS: Laparoscopic gastrectomy with No. 11p lymph node dissection with preoperative simulation using three-dimensional computed tomography was performed in 24 patients at our institution from October 2016 to May 2018. Initially, preoperative three-dimensional computed tomography findings with operative videos in these 24 patients were compared. The dorsal landmark was defined as an anatomical structure behind the splenic artery on preoperative three-dimensional computed tomography and operative videos. The dorsal landmark of No. 11p lymph node was divided into four types: (1) splenic vein type, (2) splenic vein and pancreas type, (3) pancreas type, and (4) unclear type. Then, to investigate the efficacy of three-dimensional computed tomography, we compared the clinical and pathological features and surgical outcomes of nine patients who underwent preoperative three-dimensional computed tomography simulation (three-dimensional computed tomography group) and 23 patients who did not undergo three-dimensional computed tomography simulation from August 2014 to September 2016 (non-three-dimensional computed tomography group). All procedures were performed by one surgeon certified by the Endoscopic Surgical Skill Qualification System in Japan. RESULTS: The concordance rate between three-dimensional computed tomography and operative videos of the dorsal landmark using three-dimensional computed tomography was 79% (19/24). The operative time of No. 11p lymph node dissection was significantly shorter in the three-dimensional computed tomography group than in the non-three-dimensional computed tomography group (7.7 versus 15.8 min, P = 0.044). CONCLUSION: The accuracy of predicting the dorsal landmark of No. 11p lymph node using three-dimensional computed tomography was extremely high. Preoperative simulation with three-dimensional computed tomography was useful in shortening the operative time of No. 11p lymph node dissection.

Correction to: Thoracic Duct Resection During Esophagectomy Does Not Contribute to Improved Prognosis in Esophageal Squamous Cell Carcinoma: A Propensity Score Matched-Cohort Study.

In the original article, there are errors in Fig. 1. Following is the corrected figure.

Three-dimensional laparoscopic vision improves forceps motion more in the depth direction than in the horizontal direction: An analysis of data from prospective randomized controlled trials.

INTRODUCTION: Three-dimensional (3D) laparoscopic vision can improve depth perception. However, it is a question whether 3D vision can improve motion in the depth direction. The aim of this study was to compare the impact of 3D vision on forceps motion in the depth and horizontal directions. METHODS: All data were obtained from our previous two studies, where, in total, 40 novices and 20 moderately experienced surgeons participated. A simple phantom task was performed in a training box. The participants were randomly assigned to two groups. Specifically, one group performed the task five times initially under a two-dimensional (2D) system, and the other group started under a 3D system. Both groups then performed the same task five times under the alternative system. Performances were recorded by an optical position tracker. We separately evaluated forceps motion in the x-, y-, and z-axis directions. RESULTS: Compared with the findings for 2D vision, the forceps path lengths were significantly decreased among novices and moderately experienced surgeons in almost all tasks under 3D vision. In a comparison of the path length ratio (3D/2D) in each direction, larger reduction was observed for the depth direction among novices, whereas no significant directional difference was noted among moderately experienced surgeons. CONCLUSIONS: For novices, 3D laparoscopic vision improves depth perception and may give shorter forceps movement in the depth direction even for simple tasks.