Long-term Survival in Esophageal Cancer: Comparison of Minimally Invasive and Open Esophagectomy.

BACKGROUND: Thoracoscopic esophagectomy is a less invasive surgical procedure; however, evidence of its effect on long-term survival is limited. We evaluated long-term survival after the procedure in patients with esophageal carcinoma. METHODS: This retrospective multicenter study involved 1,559 consecutive patients with esophageal carcinoma who underwent thoracoscopic esophagectomy or open esophagectomy between 2012 and 2019 at two Japanese high-volume cancer centers. Propensity score matching analysis was performed to compare short- and long-term outcomes. Additionally, stage-specific survival rates were compared between the two groups. RESULTS: Three-hundred-and-thirteen patients were matched and analyzed. The 1-, 3-, and 5-year overall survival rates were 84.5%, 60.5%, and 52.1%, respectively, in the matched open esophagectomy group; and 87.2%, 68.6%, and 61.8%, respectively, in the matched thoracoscopic esophagectomy group. The weighted Cox regression model showed significantly better survival in the thoracoscopic esophagectomy group than in the open esophagectomy group (hazard ratio = 0.74, 95% confidence interval: 0.582-0.941). Deaths from other causes occurred more frequently in the open esophagectomy group than in the thoracoscopic esophagectomy group. Stratified analysis showed no significant survival differences between the cStage I or II and pStage 0 or I subgroups. However, the thoracoscopic esophagectomy groups with cStage III or IV and pStage II, III, or IV had significantly better overall survival. CONCLUSIONS: This study demonstrated the survival benefits of thoracoscopic esophagectomy particularly for highly advanced esophageal carcinoma.

Robot-assisted cervical esophagectomy with simultaneous transhiatal abdominal procedure for thoracic esophageal carcinoma.

BACKGROUND: Minimally invasive robot-assisted cervical esophagectomy has been sporadically reported as a novel thoracic esophagectomy technique for patients with thoracic esophageal carcinoma. Most reports indicate that the abdominal component of robot-assisted cervical esophagectomy is performed sequentially after the cervical phase. However, if the cervical and abdominal phases are performed simultaneously using a nerve integrity monitoring system with no administration of muscle relaxants, there are two major advantages: a reduced risk of recurrent nerve palsy and a shorter operative time. We herein report our experience performing novel robot-assisted transcervical esophagectomy with a simultaneous transhiatal abdominal approach using a nerve integrity monitoring system. METHODS: Thirty cases of robot-assisted cervical esophagectomy performed from 2023 to April 2024 were reviewed. The operative and short-term surgical outcomes of this procedure were compared with those of robot-assisted cervical esophagectomy using a sequential abdominal approach, and the feasibility and efficacy of the simultaneous procedure were analyzed. RESULTS: All patients successfully underwent robot-assisted cervical esophagectomy with no intraoperative adverse events. There were no differences in the patients' demographic or operative data between the two groups. There was no difference in the mean operation time for the cervical procedure (p = 0.23). However, there was a significant difference in the total time for the whole procedure (sequential group: 453.8 ± 26.8 min, simultaneous group: 291.2 ± 36.1 min; p < 0.01). There were no differences in postoperative surgical complications between the groups. There was also no difference in the total number of surgically harvested mediastinal lymph nodes (p = 0.33). CONCLUSIONS: Robot-assisted transcervical esophagectomy, a new technique for thoracic esophageal cancer, was safe and feasible under intraoperative management using nerve integrity monitoring without muscle relaxants. This procedure facilitates intraoperative monitoring of recurrent laryngeal nerve activity, significantly shortening the total operative time.

Investigation of pulmonary inflammatory responses following intratracheal instillation of and inhalation exposure to polypropylene microplastics.

BACKGROUND: Microplastics have been detected in the atmosphere as well as in the ocean, and there is concern about their biological effects in the lungs. We conducted a short-term inhalation exposure and intratracheal instillation using rats to evaluate lung disorders related to microplastics. We conducted an inhalation exposure of polypropylene fine powder at a low concentration of 2 mg/m3 and a high concentration of 10 mg/m3 on 8-week-old male Fischer 344 rats for 6 h a day, 5 days a week for 4 weeks. We also conducted an intratracheal instillation of polypropylene at a low dose of 0.2 mg/rat and a high dose of 1.0 mg/rat on 12-week-old male Fischer 344 rats. Rats were dissected from 3 days to 6 months after both exposures, and bronchoalveolar lavage fluid (BALF) and lung tissue were collected to analyze lung inflammation and lung injury. RESULTS: Both exposures to polypropylene induced a persistent influx of inflammatory cells and expression of CINC-1, CINC-2, and MPO in BALF from 1 month after exposure. Genetic analysis showed a significant increase in inflammation-related factors for up to 6 months. The low concentration in the inhalation exposure of polypropylene also induced mild lung inflammation. CONCLUSION: These findings suggest that inhaled polypropylene, which is a microplastic, induces persistent lung inflammation and has the potential for lung disorder. Exposure to 2 mg/m3 induced inflammatory changes and was thought to be the Lowest Observed Adverse Effect Level (LOAEL) for acute effects of polypropylene. However, considering the concentration of microplastics in a real general environment, the risk of environmental hazards to humans may be low.

Iodine identification in major edible seaweed Kappaphycus alvarezii and establishment of an iodine reduction method for its protein extract for utilization as a protein source.

Kappaphycus alvarezii is the most widely cultivated seaweed globally. The use of the protein contained in K. alvarezii as an alternative protein source seems to be an effective countermeasure against the protein crisis. Here, we identified the iodine chemical species in K. alvarezii and developed an iodine reduction method. We used various fractionation methods and showed that almost all the iodine in the K. alvarezii alkali extract is present as an iodinated protein, and reducing the amount of iodine per protein was difficult. Subsequently, an iodine reduction method was established to cleave the covalent bonds between the protein and iodine, and we could successfully reduce the amount of iodine per protein by approximately half.

Assessing the outcomes of posterior thoracic para-aortic lymph node dissection after induction chemotherapy in patients with esophageal squamous cell carcinoma.

Posterior thoracic para-aortic lymph node (TPAN) metastasis is a distant metastasis of esophageal cancer. Several case reports have shown that radical esophagectomy and lymphadenectomy for posterior TPAN improve the prognosis of patients with cStage IVB esophageal cancer and solitary posterior TPAN metastasis; however, the true value of this procedure is unclear. The primary objective of this study was to evaluate the short- and long-term outcomes of lymphadenectomy for posterior TPAN after induction chemotherapy in esophageal cancer. This study enrolled 15 patients who underwent radical esophagectomy for cStage IVB esophageal cancer with solitary posterior TPAN metastasis after induction chemotherapy between January 2013 and October 2022 at our hospital. The short- and long-term of radical esophagectomy and lymphadenectomy for posterior TPAN were retrospectively evaluated. All patients who underwent radical esophagectomy and lymphadenectomy for posterior TPAN achieved a pR0 in this study. The median operative time and intraoperative blood loss were 385 minutes and 164 ml, respectively. Four patients (26.7%) had postoperative complications of Clavien-Dindo grade II or more. The median postoperative hospital stay was 15 days. The 5-year overall survival and recurrence-free survival rates were 55.6% (95% confidence interval: 23.1-79.0) and 55.0% (95% confidence interval: 25.3-77.2), respectively. We showed that lymphadenectomy for posterior TPAN metastasis was associated with an improved prognosis of some patients with advanced esophageal cancer. This technique may serve as a viable treatment option for patients who respond well to induction chemotherapy.

Total RAMIE with three-field lymph node dissection by a simultaneous two-team approach using a new docking method for esophageal cancer.

BACKGROUND: Thoracic esophageal cancer surgery using robotic approaches for the thoracic and abdominal parts has recently been reported as total robot-assisted minimally invasive esophagectomy (RAMIE). We herein present the first report of a new technique for esophageal cancer: total RAMIE with three-field lymph node dissection (3FLND) by a simultaneous two-team approach using a new docking method. METHODS: We reviewed 20 patients who underwent total RAMIE with 3FLND by a simultaneous two-team approach at the National Cancer Center East Hospital from March 2023 to September 2023. Short-term surgical outcomes and the safety and efficacy of this technique were analyzed. RESULTS: The mean operative time for abdominal surgery with this new docking technique was 135 ± 19.6 min. The total operative time was 488 ± 42.9 min, and the time from the end of abdominal manipulation to the end of surgery was 80.1 ± 15.6 min. The intraoperative blood loss was 116.7 ± 64.4 mL. The incidence of anastomotic leakage, postoperative vocal cord paralysis, and postoperative pneumonia was 10%, 5%, and 10%, respectively. The median postoperative hospital stay was 14 days (range 11-63 days). No in-hospital deaths occurred, and R0 resection was possible in all cases. The average number of lymph nodes dissected was 87.7. CONCLUSION: These results demonstrate that total RAMIE with a simultaneous two-team approach using the new docking method can be safely introduced. The simultaneous cervical and abdominal manipulation with the new docking method allowed total RAMIE without prolonging the operating time, suggesting that it may be a valuable approach for esophageal cancer surgery.

Efficiency of conversion surgery for esophageal squamous cell carcinoma with solitary abdominal para-aortic lymph node metastasis.

PURPOSE: Abdominal para-aortic lymph nodes (PANs) are sites of distant metastasis in esophageal squamous cell cancer (ESCC). The prognosis of patients with Stage IVB ESCC and abdominal PAN metastasis is extremely poor. However, chemotherapy for ESCC has recently been developed, and the effectiveness of combined induction therapy and conversion surgery remains unclear. The primary objective of this study was to evaluate the short- and long-term outcomes of conversion surgery for ESCC and solitary abdominal PAN metastases after induction therapy. METHODS: Thirteen patients who underwent conversion esophagectomy for cStage IVB ESCC with solitary abdominal PAN metastasis after induction therapy between January 2017 and October 2022 at our institution were enrolled. The short- and long-term outcomes of conversion surgery were retrospectively evaluated. RESULTS: Three patients (23.1%) had pathological abdominal PAN metastasis, and six patients (46.2%) without pathological abdominal PAN metastasis showed that chemotherapy eliminated the tumors in the abdominal PAN. Three patients (23.1%) had postoperative complications of Clavien-Dindo grade II or higher. The 3-year overall and recurrence-free survival rates were 83.1% and 51.3%, respectively. CONCLUSIONS: Our findings showed that conversion surgery for ESCC and solitary abdominal PAN metastasis led to a good prognosis when induction therapy was successful.

Prognosis of patients with residual pathological disease after neoadjuvant docetaxel, cisplatin, and 5-fluorouracil therapy and surgery for esophageal squamous cell carcinoma: a retrospective cohort study.

Background: Docetaxel, cisplatin, and 5-fluorouracil (DCF) combination chemotherapy has been established as one of the standard neoadjuvant therapies for locally advanced esophageal squamous cell carcinoma (ESCC). However, little is known about prognostic factors in patients with residual pathological disease after neoadjuvant DCF followed by surgery for locally advanced ESCC who are candidates for adjuvant nivolumab. Objectives: This study aimed to investigate prognostic factors in patients with residual pathological disease after neoadjuvant DCF chemotherapy followed by surgery for locally advanced ESCC. Design: This was a retrospective cohort study. Methods: This retrospective cohort study included patients who received neoadjuvant DCF followed by surgery for locally advanced ESCC between June 2014 and January 2020 at the National Cancer Center Hospital East. Results: Among a total of 210 patients, 45 patients (21.4%) achieved a pathological complete response. The 3-year disease-free survival (DFS) rate was significantly lower in patients with residual pathological disease than in those with a pathological complete response [53.5% versus 74.5%; hazard ratio (HR): 2.09, 95% confidence interval (CI): 1.16-3.77, p = 0.01]. In patients with residual pathological disease (n = 165), multivariate analysis revealed that pathological node positivity (HR: 3.59, 95% CI: 1.92-6.71, p < 0.01), supraclavicular lymph node metastasis (HR: 2.15, 95% CI: 1.19-3.90, p = 0.01), and lymphovascular invasion (HR: 1.90, 95% CI: 1.14-3.17, p = 0.02) were significantly associated with poor DFS. Conclusion: In this largest-to-date cohort study, patients with residual pathological disease after neoadjuvant DCF followed by surgery for locally advanced ESCC had a poor prognosis. In these patients, pathological node positivity, including supraclavicular lymph node metastasis, and lymphovascular invasion were considered significant prognostic factors.

Robot-assisted transcervical esophagectomy with a bilateral cervical approach for thoracic esophagectomy.

BACKGROUND: Thoracic esophageal cancer resection through the neck approach has recently been reported as mediastinoscopic surgery. We present the first report of a new minimally invasive technique for thoracic esophageal cancer: robot-assisted transcervical esophagectomy with a bilateral cervical approach. METHODS: Ten cases of robot-assisted bilateral transcervical esophagectomy performed at the National Cancer Center Hospital East, Japan, from February 2023 to August 2023 were reviewed. The short-term surgical outcomes were presented, and the feasibility and efficacy of this procedure were discussed. RESULTS: The mean operation time for the cervical procedure was 184.2 ± 23.6 min. The total time for the whole procedure was 472.7 ± 28.4 min, and total intraoperative blood loss was 162.2 ± 40.0 ml. Among the 10 cases, one patient developed recurrent nerve paralysis, one patient developed pulmonary complications, and no patients developed postoperative pneumonia. The median postoperative hospital stay was 22 (range: 12-43) days. No patients developed severe postoperative surgical complications, which were graded as Clavien-Dindo ≥ III. The total number of surgically harvested mediastinal lymph nodes was 37.2 ± 11.2. CONCLUSIONS: Robot-assisted bilateral transcervical esophagectomy, a novel procedure for thoracic esophageal cancer, was safe and feasible. Using this procedure, the incidence of recurrent nerve palsy, which is a problem with transcervical esophagectomy and mediastinoscopic esophagectomy, is expected to decrease.

A novel device to assess the oxygen saturation and congestion status of the gastric conduit in thoracic esophagectomy.

BACKGROUND: In thoracic esophagectomy, anastomotic leakage is one of the most important surgical complications. Indocyanine green (ICG) is the most widely used method to assess tissue blood flow; however, this technique has been pointed out to have disadvantages such as difficulty in evaluating the degree of congestion, lack of objectivity in evaluating the degree of staining, and bias easily caused by ICG injection, camera distance, and other factors. Evaluating tissue oxygen saturation (StO2) overcomes these disadvantages and can be performed easily and repeatedly. It is also possible to measure objective values including the degree of congestion. We evaluate novel imaging technology to assess tissue oxygen saturation (StO2) in the gastric conduit during thoracic esophagectomy. METHODS: Fifty patients were enrolled, with seven excluded due to intraoperative findings, leaving 43 for analysis. These patients underwent thoracic esophagectomy for esophageal cancer. The device was used intraoperatively to evaluate tissue oxygen saturation (StO2) and total hemoglobin index (T-HbI), which guided the optimal site for gastric tube anastomosis. The efficacies of StO2 and T-HbI in relation to short-term outcomes were analyzed. RESULTS: StO2, indicating blood supply to the gastric tube, remained stable beyond the right gastroepiploic artery (RGEA) end but significantly decreased distally to the demarcation line (p <  0.05). T-HbI, indicative of congestion, significantly decreased past the RGEA (p <  0.05). Three patients experienced anastomotic leakage. These patients exhibited significantly lower StO2 (p <  0.01) and higher T-HbI (p <  0.01) at both the RGEA end and the demarcation line. Furthermore, the anastomotic site, usually within 3 cm of the RGEA's anorectal side, also showed significantly lower StO2 (p <  0.01) and higher T-HbI (p <  0.01) in patients with anastomotic leakage. CONCLUSIONS: The novel device provides real-time, objective evaluations of blood flow and congestion in the gastric tube. It proves useful for safer reconstruction during thoracic esophagectomy, particularly by identifying optimal anastomosis sites and predicting potential anastomotic leakage.

A novel imaging technology to assess tissue oxygen saturation and its correlation with indocyanine green in the gastric conduit during thoracic esophagectomy.

BACKGROUND: Anastomotic leakage in esophagectomy is a serious complication, and assessing blood perfusion in the conduit can help minimize this risk. Indocyanine green is the most widely used method to assess tissue blood flow; however, this technique has disadvantages. Evaluating tissue oxygen saturation in the gastric conduit during thoracic esophagectomy compared with indocyanine green blood perfusion assessment addresses these disadvantages and can be performed easily and repeatedly. METHODS: This was a prospective study of patients with esophageal cancer who underwent thoracic esophagectomy. Intraoperative tissue oxygen saturation and indocyanine green measurements were obtained to determine the anastomotic site and to compare the correlation between the 2 methods. Tissue oxygen saturation and indocyanine green values were obtained at the tip of the gastric conduit, the demarcation line indicating visible perfusion, and the end of the right gastroepiploic artery. RESULTS: Fifty-seven patients were enrolled in this study; 3 developed anastomotic leakage, and all 3 underwent robotic thoracic surgery. The tissue oxygen saturation value decreased gradually toward the tip of the conduit, as did congestion, and was significantly decreased at the tip compared with the value at the demarcation line (P = .001). Mean tissue oxygen saturation differed significantly between the leakage and no-leakage groups at the anastomosis site (P = .04). We found a negative correlation between tissue oxygen saturation and indocyanine green values at the end of the right gastroepiploic artery (r = -0.361; P = .03). CONCLUSION: Tissue oxygen saturation imaging was useful in determining the anastomotic site and addressed the disadvantages associated with indocyanine green.

[Management of Postoperative Infectious Complications After Thoracic Esophagectomy].

Although minimally invasive procedures such as thoracoscopic surgery and robot-assisted surgery have become increasingly popular in esophageal cancer in recent years, perioperative management remains a very important topic. However, perioperative management is still an extremely important issue, as esophagectomy is still a highly invasive procedure. Especially in recent years, as the patient population ages, it is expected that we will have more and more opportunities to deal with patients with various pre-existing medical conditions in addition to the original decline in physical function. In this article, we discuss the management of infectious complications in the perioperative management of esophageal surgery, with a particular focus on esophagectomy and reconstruction.

The feasibility of post-photodynamic therapy salvage esophagectomy in patients with esophageal squamous cell carcinoma treated with definitive chemoradiotherapy.

BACKGROUND: Photodynamic therapy (PDT) is a minimally invasive salvage treatment for local residual or recurrent lesions that persist after the definitive chemoradiotherapy (dCRT) of esophageal cancer. However, esophageal cancer persistence after PDT is associated with a poor prognosis. Although esophagectomy is a curative treatment option, few studies have evaluated its efficacy. Thus, this study aimed to evaluate the outcomes of salvage esophagectomy after PDT. METHODS: 14 patients who underwent salvage esophagectomy for residual or recurrent esophageal cancer after PDT between April 2006 and November 2022 at our institution, were enrolled. The short-term (e.g., blood loss, operative time, R0 rate, postoperative complications, and postoperative hospital stay) and long-term (e.g., overall survival [OS] and recurrence-free survival [RFS]) of salvage esophagectomy after PDT were evaluated retrospectively. RESULTS: The median operative time and intraoperative blood loss were 355 min and 350 ml, respectively. Eight patients (57.1%) had postoperative complications of Clavien-Dindo grade II or more. The median postoperative hospital stay was 20.5 days. The 3-year OS and RFS rates were 23.5% (95% confidence interval [CI] 5.7-48.0) and 16.3% (95% CI 2.7-40.3), respectively. Seven patients with an R0 had significantly longer OS than the seven patients with R1 and 2 (p = 0.045). The 3-year OS rate for patients with R0 was 52.6%. CONCLUSIONS: Although salvage esophagectomy after PDT carries certain risks, patients who achieved an R0 had a promising long-term prognosis. The location and size of the lesion may be critical factors in determining whether R0 can be achieved with salvage esophagectomy after PDT.

Impact of pre-diabetes, well-controlled diabetes, and poorly controlled diabetes on anastomotic leakage after esophagectomy for esophageal cancer: a two-center retrospective cohort study of 1901 patients.

BACKGROUND: Diabetes is known to be associated with anastomotic leakage (AL) after esophagectomy. However, it is unknown whether well-controlled diabetes is also associated with AL. METHODS: We conducted a two-center retrospective cohort database study of patients who underwent oncological esophagectomy (2011-2019). Patients were divided into four groups: normoglycemia, pre-diabetes, well-controlled diabetes (hemoglobin A1c [HbA1c] < 7.0%), and poorly controlled diabetes (HbA1c ≥ 7.0%). The occurrence of AL and length of stay were compared between groups using multivariable analyses. The relationship between categorical HbA1c levels and AL was also investigated in patients stratified by diabetes medication before admission. RESULTS: Among 1901 patients, 1114 (58.6%) had normoglycemia, 480 (25.2%) had pre-diabetes, 180 (9.5%) had well-controlled diabetes, and 127 (6.7%) had poorly controlled diabetes. AL occurred in 279 (14.7%) patients. Compared with normoglycemia, AL was significantly associated with both well-controlled diabetes (odds ratio 1.83, 95% confidence interval [CI] 1.22-2.74) and poorly controlled diabetes (odds ratio 1.95, 95% CI 1.23-3.09), but not with pre-diabetes. Preoperative HbA1c levels showed a J-shaped association with AL in patients without diabetes medication, but no association in patients with diabetes medication. Compared with normoglycemia, only poorly controlled diabetes was significantly associated with longer hospital stay after surgery, especially in patients with operative morbidity (unstandardized coefficient 14.9 days, 95% CI 5.6-24.1). CONCLUSIONS: Diabetes was associated with AL after esophagectomy even in well-controlled patients, but pre-diabetes was not associated with AL. Operative morbidity, including AL, in poorly controlled diabetes resulted in prolonged hospital stays compared with normoglycemia.

Mathematical analysis of phototransduction reaction parameters in rods and cones.

Retinal photoreceptor cells, rods and cones, convert photons of light into chemical and electrical signals as the first step of the visual transduction cascade. Although the chemical processes in the phototransduction system are very similar to each other in these photoreceptors, the light sensitivity and time resolution of the photoresponse in rods are functionally different than those in the photoresponses of cones. To systematically investigate how photoresponses are divergently regulated in rods and cones, we have developed a detailed mathematical model on the basis of the Hamer model. The current model successfully reconstructed light intensity-, ATP- and GTP-dependent changes in concentrations of phosphorylated visual pigments (VPs), activated transducins (Tr*s) and phosphodiesterases (PDEs) in rods and cones. In comparison to rods, the lower light sensitivity of cones was attributed not only to the lower affinity of activated VPs for Trs but also to the faster desensitization of the VPs. The assumption of an intermediate inactive state, MIIi, in the thermal decay of activated VPs was essential for inducing faster inactivation of VPs in rods, and possibly also in cones.

Propensity-Matched Analysis of the Short-Term Outcome of Robot-Assisted Minimally Invasive Esophagectomy Versus Conventional Thoracoscopic Esophagectomy in Thoracic Esophageal Cancer.

BACKGROUND: In this matched-cohort study, we investigated the short-term outcome of robot-assisted minimally invasive esophagectomy (RAMIE) compared with conventional minimally invasive thoracoscopic esophagectomy (MIE) in esophageal cancer patients. METHODS: One hundred eighty-nine patients with thoracic esophageal cancer scheduled to undergo thoracic esophagectomy between 2020 and 2021 were assigned to either RAMIE or MIE. Then, we retrospectively evaluated the postoperative surgical complications between two groups in a propensity-matched analyzation. RESULTS: Based on the propensity-matched score, 50 patients who underwent RAMIE or MIE were selected. Thoracic surgery time in RAMIE/MIE group were 233.1/173.3 min (p < 0.01), respectively. No significant intergroup differences were observed regarding incisional anastomotic leakage (RAMIE group 4.0% vs. MIE group 6.0%) and pneumonia (RAMIE group 8.0% vs. MIE group 12.0%; p = 0.68). The respective incidences of recurrent laryngeal nerve paralysis were 34.0 and 8.0% in the MIE and RAMIE groups, respectively (p < 0.01). In the matched cohort, no differences were observed between the groups in the success accomplishment of the clinical management pathway (RAMIE group 94.0% vs. MIE group 88.0%). CONCLUSIONS: Although patients who underwent RAMIE had longer operation times, the incidence of recurrent laryngeal nerve paralysis was lower than with MIE. Further study in a prospective multi-institutional setting are required to confirm the superiority of RAMIE compared with MIE.

Real-time detection of the recurrent laryngeal nerve in thoracoscopic esophagectomy using artificial intelligence.

BACKGROUND: Artificial intelligence (AI) has been largely investigated in the field of surgery, particularly in quality assurance. However, AI-guided navigation during surgery has not yet been put into practice because a sufficient level of performance has not been reached. We aimed to develop deep learning-based AI image processing software to identify the location of the recurrent laryngeal nerve during thoracoscopic esophagectomy and determine whether the incidence of recurrent laryngeal nerve paralysis is reduced using this software. METHODS: More than 3000 images extracted from 20 thoracoscopic esophagectomy videos and 40 images extracted from 8 thoracoscopic esophagectomy videos were annotated for identification of the recurrent laryngeal nerve. The Dice coefficient was used to assess the detection performance of the model and that of surgeons (specialized esophageal surgeons and certified general gastrointestinal surgeons). The performance was compared using a test set. RESULTS: The average Dice coefficient of the AI model was 0.58. This was not significantly different from the Dice coefficient of the group of specialized esophageal surgeons (P = 0.26); however, it was significantly higher than that of the group of certified general gastrointestinal surgeons (P = 0.019). CONCLUSIONS: Our software's performance in identification of the recurrent laryngeal nerve was superior to that of general surgeons and almost reached that of specialized surgeons. Our software provides real-time identification and will be useful for thoracoscopic esophagectomy after further developments.

A novel imaging technology to assess oxygen saturation of the gastric conduit in thoracic esophagectomy.

BACKGROUND: Real-time evaluation of blood perfusion is important when selecting the site of anastomosis during thoracic esophagectomy. This study investigated a novel imaging technology that assesses tissue oxygen saturation (StO2) in the gastric conduit and examined its efficacy. METHODS: Fifty-one patients undergoing thoracic esophagectomy for esophageal cancer who underwent intraoperative StO2 endoscopic imaging to assess the gastric conduit for the optimal site of anastomosis were examined. Efficacy of oxygen saturation imaging and patient outcomes were analyzed. RESULTS: All 51 patients underwent esophagectomy without intraoperative problems. Mean StO2 in the gastric tube was highest at the pre-pylorus area and then gradually decreased proceeding toward the tip. StO2 was well preserved in areas supplied by the right gastroepiploic artery but low in other areas. Anastomotic sites were selected based on StO2 imaging and tension considerations; most were located within 3 cm of the end of the right gastroepiploic artery. Three patients developed postoperative anastomotic leakage (5.8%). Mean StO2 at the point of anastomosis was significantly lower in the patients who experienced leakage than in those who did not (P = 0.04). CONCLUSION: Intraoperative endoscopic StO2 imaging is useful in esophageal cancer patients undergoing thoracic esophagectomy to determine the optimal site for anastomosis to minimize the risk of anastomotic leakage.