Effects of communication delay in the dual cockpit remote robotic surgery system

PURPOSE

To evaluate the impact of dual cockpit telesurgery on proctors and operators, and acceptable levels of processing delay for video compression and restoration.

METHODS

Eight medical advisors and eight trainee surgeons, one highly skilled per group, performed gastrectomy, rectal resection, cholecystectomy, and bleeding tasks on pigs. Using the Medicaroid surgical robot hinotori™, simulated delay times (0 ms, 50 ms, 100 ms, 150 ms, and 200 ms) were inserted mid-surgery to evaluate the tolerance level. Operative times and dual cockpit switching times were measured subjectively using 5-point scale questionnaires (mSUS [modified System Usability Scale], and Robot Usability Score).

RESULTS

No significant difference was observed in operative times between proctors and operators (proctor: p = 0.247, operator: p = 0.608) nor in switching times to the dual cockpit mode (p = 0.248). For each survey setting, proctors tended to give lower ratings to delays of ≥ 150 ms. No marked difference was observed in the operator evaluations. On the postoperative questionnaires, there were no marked differences in the mSUS or Robot Usability Score between the proctors and operators (mSUS: p = 0.779, Robot Usability Score: p = 0.261).

CONCLUSION

Telesurgery using a dual cockpit with hinotori™ is practical and has little impact on surgical procedures.

Postoperative long‑term outcomes of acute normovolemic hemodilution in pancreatic cancer: A propensity score matching analysis

Acute normovolemic hemodilution (ANH) is a useful intraoperative blood conservation technique. However, the impact on long-term outcomes in pancreatic ductal adenocarcinoma (PDAC) remains unclear. The present study investigated the impact of ANH on long-term outcomes in patients with PDAC undergoing radical surgery. Data from 155 resectable PDAC cases were collected. Patients were categorized according to whether or not they had received intraoperative allogeneic blood transfusion (ABT) or ANH. Postoperative complications, recurrence-free survival (RFS) and disease-specific survival (DSS), before and after propensity score matching (PSM), were compared among patients who did and did not receive ANH. A total of 44 patients (28.4%) were included in the ANH group and 30 patients (19.4%) were included in the ABT group; 81 (52.3%) patients, comprising the standard management (STD) group, received neither ANH nor ABT. The ABT group had the worst prognosis among them. Before PSM, ANH was significantly associated with decreased RFS (P=0.043) and DSS (P=0.029) compared with the STD group before applying Bonferroni correction; however, no significant difference was observed after applying Bonferroni correction. Cox regression analysis identified ANH as an independent prognostic factor for RFS [relative risk (RR), 1.696; P=0.019] and DSS (RR, 1.876; P=0.009). After PSM, the ANH group exhibited less favorable RFS [median survival time (MST), 12.1 vs. 18.1 months; P=0.097] and DSS (MST, 32.1 vs. 50.5 months; P=0.097) compared with the STD group; however, these differences were not statistically significant. In conclusion, while ANH was not as harmful as ABT, it exhibited potentially more negative effects on long-term postoperative outcomes in PDAC than STD.

Immunohistochemical and molecular profiles of heterogeneous components of metaplastic breast cancer: a squamous cell carcinomatous component was distinct from a spindle cell carcinomatous component

Metaplastic breast carcinoma (MBC), a category of breast cancer, includes different histological types, which are occasionally mixed and heterogeneous. Considering the heterogeneity of cancer cells in a tumour mass has become highly significant, not only from a biological aspect but also for clinical management of recurrence. This study aimed to analyse the immunohistochemical and molecular profiles of each MBC component of a tumour mass. Twenty-five MBC tumours were histologically evaluated, and the most frequent MBC component (c) was squamous cell carcinoma (SCC), followed by spindle cell carcinoma (SpCC). A total of 69 components of MBC and non-MBC in formalin-fixed paraffin-embedded sections were examined for 7 markers by immunohistochemistry. SCC(c) were significantly PTEN negative and CK14 positive, and SpCC(c) were significantly E-cadherin negative and vimentin positive. Multivariate analyses revealed that immunohistochemical profiles of normal/intraductal (IC)(c), no special type (NST)(c), and MBC(c) differed; moreover, SCC(c) and SpCC(c) were distinctly grouped. PTEN gene mutation was detected only in SCC(c) (2/7), but not in SpCC(c). Next-generation sequence analyses for 2 cases with tumours containing SCC(c) demonstrated that PTEN gene mutation increased progressively from IC(c) to NST(c) to SCC(c). In conclusion, the immunohistochemical and molecular profiles of the SCC(c) of MBC are distinct from those of the SpCC(c).

Field experiment of a telesurgery system using a surgical robot with haptic feedback

PURPOSE

To verify the usefulness of haptic feedback in telesurgery and improve the safety of telerobotic surgery.

METHODS

The surgeon's console was installed at two sites (Fukuoka and Beppu; 140 km apart), and the patient cart was installed in Fukuoka. During the experiment, the surgeon was blinded to the haptic feedback levels and asked to grasp the intestinal tract in an animal model. The surgeon then performed the tasks at each location.

RESULTS

No marked differences in task accuracy or average grasping force were observed between the surgeon locations. However, the average task completion time was significantly longer, and the system usability scale (SUS) was significantly lower rating for remote operations than for local ones. No marked differences in task accuracy or task completion time were observed between the haptic feedback levels. However, with haptic feedback, the organ was grasped with a significantly weaker force than that without it. Furthermore, with haptic feedback, experienced surgeons in robotic surgery tended to perform an equivalent task with weaker grasping forces than inexperienced surgeons.

CONCLUSION

The haptic feedback function is a tool that allows the surgeon to perform surgery with an appropriate grasping force, both on site and remotely. Improved safety is necessary in telesurgery; haptic feedback will thus be an essential technology in robotic telesurgery going forward.

Follicular dendritic cell sarcoma arising from the lymph node of the pancreatic head: a case report with literature review

A 72-year-old man was referred to our hospital for the examination of a pancreatic head mass. Abdominal computed tomography revealed a contrasted 8-cm-diameter tumor extending from the dorsal pancreatic head to the porta hepatis. The preoperative diagnosis was challenging due to the absence of specific imaging findings and the inability to perform a biopsy. Positron emission tomography/computed tomography and diffusion-weighted imaging suggested a malignant tumor originating from the organs surrounding the pancreatic head. Subtotal stomach-preserving pancreaticoduodenectomy with regional lymph node dissection was performed, as dissection from the pancreatic head proved unfeasible. Pathological examination identified the tumor as an enlarged lymph node consisting of pleomorphic large cells forming clusters, positive for follicular dendritic cell markers cluster of differentiation (CD) 21 and CD23. No evidence of tumor capsule infiltration, other organ infiltration, or metastasis to other lymph nodes was observed. The final diagnosis was nodal follicular dendritic cell sarcoma (FDCS) originating from the pancreatic head lymph nodes. No recurrence occurred at 3 years postoperatively with no postoperative treatment. Intraperitoneal nodal FDCS is extremely rare, and occasionally, it can lead to postoperative recurrence and progression. It is crucial to differentiate neoplastic lymph node enlargement around the pancreatic head from nodal FDCS.

Tryptophan metabolism and small fibre neuropathy: a correlation study

Small nerve fibres located in the epidermis sense pain. Dysfunction of these fibres decreases the pain threshold known as small fibre neuropathy. Diabetes mellitus is accompanied by metabolic changes other than glucose, synergistically eliciting small fibre neuropathy. These findings suggest that various metabolic changes may be involved in small fibre neuropathy. Herein, we explored the correlation between pain sensation and changes in plasma metabolites in healthy Japanese subjects. The pain threshold evaluated from the intraepidermal electrical stimulation was used to quantify pain sensation in a total of 1021 individuals in the 2017 Iwaki Health Promotion Project. Participants with a pain threshold evaluated from the intraepidermal electrical stimulation index <0.20 mA were categorized into the pain threshold evaluated from the intraepidermal electrical stimulation index-low group (n = 751); otherwise, they were categorized into the pain threshold evaluated from the intraepidermal electrical stimulation index-high group (n = 270). Metabolome analysis of plasma was conducted using capillary electrophoresis time-of-flight mass spectrometry. The metabolite set enrichment analysis revealed that the metabolism of tryptophan was significantly correlated with the pain threshold evaluated from the intraepidermal electrical stimulation index in all participants (P < 0.05). The normalized level of tryptophan was significantly decreased in participants with a high pain threshold evaluated from the intraepidermal electrical stimulation index. In addition to univariate linear regression analyses, the correlation between tryptophan concentration and the pain threshold evaluated from the intraepidermal electrical stimulation index remained significant after adjustment for multiple factors (β = -0.07615, P < 0.05). These findings indicate that specific metabolic changes are involved in the deterioration of pain thresholds. Here, we show that abnormal tryptophan metabolism is significantly correlated with an elevated pain threshold evaluated from the intraepidermal electrical stimulation index in the Japanese population. This correlation provides insight into the pathology and clinical application of small fibre neuropathy.

Revealing the role of early peripancreatic bacterial contamination and Enterococcus faecalis in pancreatic fistula development after pancreaticoduodenectomy: Implications for useful antibiotic prophylaxis-An observational cohort study

BACKGROUND

Peripancreatic bacterial contamination (PBC) is a critical factor contributing to the development of clinically relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD). Controlling pathogenic bacteria is essential in preventing CR-POPF; however, the precise relationship between specific bacteria and CR-POPF remains unclear. This study aimed to investigate the relationship between PBC and CR-POPF after PD, with a focus on identifying potentially causative bacteria.

METHODS

This prospective observational study enrolled 370 patients who underwent PD. Microbial cultures were routinely collected from peripancreatic drain fluid on postoperative days (PODs) 1, 3, and 6. Predictive factors for CR-POPF and the bacteria involved in PBC were investigated.

RESULTS

CR-POPF occurred in 86 (23.2%) patients. In multivariate analysis, PBC on POD1 (Odds ratio [OR] = 3.59; P = 0.005) was one of the main independent predictive factors for CR-POPF, while prophylactic use of antibiotics other than piperacillin/tazobactam independently influenced PBC on POD1 (OR = 2.95; P = 0.010). Notably, Enterococcus spp., particularly Enterococcus faecalis, were significantly isolated from PBC in patients with CR-POPF compared to those without CR-POPF on PODs 1 and 3 (P < 0.001), and they displayed high resistance to all cephalosporins.

CONCLUSIONS

Early PBC plays a pivotal role in the development of CR-POPF following PD. Prophylactic antibiotic administration, specifically targeting Enterococcus faecalis, may effectively mitigate early PBC and subsequently reduce the risk of CR-POPF. This research sheds light on the importance of bacterial control strategies in preventing CR-POPF after PD.

[A Case of Breast Cancer That Developed Pulmonary Tumor Thrombotic Microangiopathy during Adjuvant Chemotherapy]

A 68-year-old woman underwent neoadjuvant chemotherapy for left breast cancer(triple negative type), cT2N3cM0, cStage ⅢC, and Bt+Ax(Ⅲ). The pathological diagnosis was ypT1aN2aM0, ypStage ⅢA, ER-, PgR-, HER2 score 1+, Ki- 67 25%. Adjuvant radiotherapy(50 Gy/25 Fr)was then administered, followed by capecitabine as adjuvant chemotherapy. Dyspnea occurred during administration of capecitabine, and computed tomography(CT)and blood test results suggested drug-induced interstitial pneumonia and disseminated intravascular coagulation(DIC). The patient was admitted, and steroid pulse therapy, anticoagulant therapy, and antibiotics were administered; however, the treatment was ineffective, and she died 3 days after admission. An autopsy provided a final diagnosis of pulmonary tumor thrombotic microangiopathy(PTTM). There is no established treatment for PTTM, and the prognosis is poor even with anticoagulant therapy and chemotherapy. The definitive diagnosis of PTTM is based on pathological findings; however, during respiratory failure, invasive tests such as lung biopsy are not recommended. Therefore, if a significantly worsening respiratory disorder develops, as in this case, chemotherapy should be considered for suspected PTTM.

Gastric cancer with enhanced myogenesis is associated with less cell proliferation, enriched epithelial-to-mesenchymal transition and angiogenesis, and poor clinical outcomes

Gastric cancer (GC) remains a lethal disease, with over 26,000 new cases and more than 11,000 deaths annually in the US. Thus, a deeper understanding of GC biology is critical to improve survival. Myogenesis is the formation of muscle fibers, which is a mesodermal tissue. In cancer, epithelial-to-mesenchymal transition (EMT) is a known phenomenon that promotes metastasis and poor survival. Given that myogenesis produces mesenchymal cells, we hypothesized that GC with increased myogenesis is linked to aggressive tumor behaviors and less favorable outcomes. In this study, three GC patient cohorts: TCGA (n=375), GSE26253 (n=432), and GSE84437 (n=482), were analyzed. The "MYOGENESIS" set in the Hallmark collection which comprises 200 myogenesis-related genes was analyzed to perform gene set variation analysis to create a score to quantify the myogenesis activity. Our results showed that T category of AJCC cancer staging that reflects the tumor invasion to stomach wall consistently correlated with myogenesis activity in two GC cohorts. High myogenesis GC was associated with lower cell proliferation, evidenced by reduced proliferation scores, decreased Ki67 gene expression, and less enrichment of E2F Targets, G2M checkpoint, MYC Targets V1, and V2 gene sets. High myogenesis tumors showed increased stromal cells (fibroblasts and adipocytes) infiltration within the tumor microenvironment, as well as less silent and non-silent mutation rates and copy number alterations. Higher lymphocyte infiltration, leukocyte fraction, T-cell receptor richness, and B-cell receptor richness were associated with high myogenesis GC. However, infiltration of CD4 cells, T helper type 1 and 2 cells, Natural Killer cells, regulatory T cells, and plasma cells was lower, with increased infiltration of dendritic cells in high myogenesis GC. High myogenesis GC enriched EMT, Hedgehog, TGF-β, and KRAS gene sets. Furthermore, it was associated with enhanced angiogenesis, evidenced by enrichment of Angiogenesis, Coagulation, and Hypoxia gene sets, and increased infiltration of microvascular and lymphatic endothelial cells and pericytes. High myogenesis GC consistently correlated with worse overall survival in all three cohorts, and worse disease-specific and progression-free survival in the TCGA cohort. Hence, our findings suggest that GC with enhanced myogenesis is associated with decreased cell proliferation, increased EMT and angiogenesis, and worse prognosis.

Ensuring communication redundancy and establishing a telementoring system for robotic telesurgery using multiple communication lines

Assuring communication redundancy during the interruption and establishing appropriate teaching environments for local surgeons are essential to making robotic telesurgery mainstream. This study analyzes robotic telesurgery with telementoring using standard domestic telecommunication carriers. Can multiple carriers guarantee redundancy with interruptions? Three commercial optical fiber lines connected Hirosaki University and Mutsu General Hospitals, 150 km apart. Using Riverfield, Inc. equipment, Hirosaki had a cockpit, while both Mutsu used both a cockpit and a surgeon's console. Experts provided telementoring evaluating 14 trainees, using objective indices for operation time and errors. Subjective questionnaires addressed image quality and surgical operability. Eighteen participants performed telesurgery using combined lines from two/three telecommunication carriers. Manipulation: over 30 min, lines were cut and restored every three minutes per task. Subjects were to press a switch when noticing image quality or operability changes. Mean time to task completion was 1510 (1186-1960) seconds: local surgeons alone and 1600 (1152-2296) seconds for those under remote instructor supervision, including expert intervention time. There was no significant difference (p = 0.86). The mean error count was 0.92 (0-3) for local surgeons and 0.42 (0-2) with remote instructors. Image quality and operability questionnaires found no significant differences. Results communication companies A, B, and C: the A/B combination incurred 0.17 (0-1) presses of the environment change switch, B/C had 0, and C/A received 0.67 (0-3), showing no significant difference among provider combinations. Combining multiple communication lines guarantees communication redundancy and enables robotic telementoring with enhanced communication security.

Tele-robotic distal gastrectomy with lymph node dissection on a cadaver

The purpose of this study is to evaluate the performance of tele-robotic distal gastrectomy (tele-RDG) with lymph node dissection (LND) using a novel Japanese-made surgical robot hinotori™ (Medicaroid, Kobe, Japan) in a cadaver with a presumptive gastric cancer. The Cadaveric Anatomy and Surgical Training Laboratory (CAST-Lab.) at Hokkaido University and Kushiro City General Hospital (KCGH) are connected by a guaranteed type line (1 Gbps), and the distance between the two facilities is 250 km. A patient cart was installed at CAST-Lab, and a surgeon cockpit was installed at KCGH. Tele-RDG with D2 LND was performed on an adult human cadaver. In all surgical processes, the communication environment was stable without image degradation, and the mean round trip time was 40 milliseconds (36.5-55 milliseconds). For tele-RDG with D2 LND, the operation time was 199 minutes without any technical problems. Tele-RDG using hinotori™ was feasible and similar to local robotic RDG.

Noninvasive Computed Tomography-Based Deep Learning Model Predicts In Vitro Chemosensitivity Assay Results in Pancreatic Cancer

OBJECTIVES

We aimed to predict in vitro chemosensitivity assay results from computed tomography (CT) images by applying deep learning (DL) to optimize chemotherapy for pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

Preoperative enhanced abdominal CT images and the histoculture drug response assay (HDRA) results were collected from 33 PDAC patients undergoing surgery. Deep learning was performed using CT images of both the HDRA-positive and HDRA-negative groups. We trimmed small patches from the entire tumor area. We established various prediction labels for HDRA results with 5-fluorouracil (FU), gemcitabine (GEM), and paclitaxel (PTX). We built a predictive model using a residual convolutional neural network and used 3-fold cross-validation.

RESULTS

Of the 33 patients, effective response to FU, GEM, and PTX by HDRA was observed in 19 (57.6%), 11 (33.3%), and 23 (88.5%) patients, respectively. The average accuracy and the area under the receiver operating characteristic curve (AUC) of the model for predicting the effective response to FU were 93.4% and 0.979, respectively. In the prediction of GEM, the models demonstrated high accuracy (92.8%) and AUC (0.969). Likewise, the model for predicting response to PTX had a high performance (accuracy, 95.9%; AUC, 0.979).

CONCLUSIONS

Our CT patch-based DL model exhibited high predictive performance in projecting HDRA results. Our study suggests that the DL approach could possibly provide a noninvasive means for the optimization of chemotherapy.

Neoadjuvant S-1 and oxaliplatin plus bevacizumab therapy for high-risk locally advanced rectal cancer: A prospective multicenter phase II study

Aim

We report the short/mid-term results of surgery for high-risk locally advanced rectal cancer (LARC) after neoadjuvant chemotherapy (NAC, four courses of S-1 + oxaliplatin+ bevacizumab) without radiotherapy with the primary aim of ypT0-2.

Methods

High-risk LARC was defined as cT4b, mesorectal fascia (MRF) ≤1 mm (MRF+), or lateral lymph node metastasis (cLLN+) on high-resolution MRI. The planned 32 cases from April 2018 to December 2021 were all included.

Results

There were 10 patients at cT4b (31.2%), 26 MRF+ (81.3%), and 22 cLLN+ (68.8%). Thirteen (40.6%) underwent NAC after a colostomy for stenosis. NAC was completed in 26 (81.2%) cases. Grade 3 or higher adverse events occurred in six (18.7%). One patient developed progressive disease (3.2%). Eleven were ycT0-3MRF-LLN- (34.3%). Curative-intent surgery was performed on 31, with sphincter-preserving surgery in 20, abdominoperineal resection in nine, total pelvic exenteration in two, and lateral lymph node dissection in 24. Two had R1/2 resection (6.4%). A Grade 3 or higher postoperative complication rate occurred in 3.2%. Pathological complete response and ypT0-2 rates were 12.9% and 45.1%. Three-year disease-free survival rates (3yDFS) for ypT0-2 and ypT ≥3 were 81.2%, 46.6% (p = 0.061), and 3-year local recurrence rates (3yLR) were 0%, 48.8% (p = 0.015). 3yDFS for ycT0-3MRF-LLN- and ycT4/MRF+/LLN+ were 87.5%, 48.0% (p = 0.031) and 3yLR were 0%, 42.8% (p = 0.045).

Conclusion

NAC yielded a clinically significant effect in about half of high-risk LARC patients. If NAC alone is ineffective, radiotherapy should be added, even if extended surgery is intended.

[A Case of Robot-Assisted Laparoscopic Surgery for Stenotic Sigmoid Colon Cancer with Simultaneous Lateral Lymph Node Metastasis]

The patient is a 63-year-old man. He visited his previous physician for abdominal pain. After close examinations, he was diagnosed with stenotic sigmoid colon cancer with left lateral lymph node metastasis. On the same day, colonic stenting was performed to relieve the symptoms of stenosis. After 1 month of stenting, a robot-assisted laparoscopic sigmoid colectomy and left lateral lymph node dissection were performed. Postoperative pathological examination revealed regional lymph node metastasis and left lateral lymph node metastasis(#283); the patient was diagnosed with pT4aN1bM1a(LYM), fStage Ⅳa. The patient was discharged on postoperative day 10, and is stable 5 months after surgery without recurrence. This case suggests that robot-assisted laparoscopic lateral lymph node dissection can be effective even in atypical cases of sigmoid colon cancer with lateral lymph node metastasis.

[A Case of Triple Negative Breast Cancer with Left Buttock Metastasis]

A female patient in her 50s was diagnosed with triple negative breast cancer in the left breast with a buttock metastasis. After neoadjuvant chemotherapy, the patient underwent surgery on the left breast. As the histopathological findings indicated a residual tumor, she was further treated with capecitabine postoperatively. Twenty months postoperatively, a CT scan revealed a tumor on her left buttock. She was also diagnosed with a relapse of the breast cancer after a core needle biopsy. She was treated with atezolizumab and nab-paclitaxel as first-line therapy for the metastasis and with eriburlin as second- line therapy. As she became uncomfortable sitting owing to the regrowth of the buttock tumor, the left buttock tumor was resected. She has been treated with bevacizumab and paclitaxel for subsequent lung metastases.

Real-time telementoring with 3D drawing annotation in robotic surgery

BACKGROUND

In telementoring, differences in teaching methods affect local surgeons' comprehension. Because the object to be operated on is a three-dimensional (3D) structure, voice or 2D annotation may not be sufficient to convey the instructor's intention. In this study, we examined the usefulness of telementoring using 3D drawing annotations in robotic surgery.

METHODS

Kyushu University and Beppu Hospital are located 140 km apart, and the study was conducted using a Saroa™ surgical robot by RIVERFIELD Inc. using a commercial guarantee network on optical fiber. Twenty medical students performed vertical mattress suturing using a swine intestinal tract under surgical guidance at the Center for Advanced Medical Innovation Kyushu University. Surgical guidance was provided by Beppu Hospital using voice, 2D, and 3D drawing annotations. All robot operations were performed using 3D images, and only the annotations were independently switched between voice and 2D and 3D images. The operation time, needle movement, and performance were also evaluated.

RESULTS

The 3D annotation group tended to have a shorter working time than the control group (25.6 ± 63.2 vs. - 36.7 ± 65.4 min, P = 0.06). The 3D annotation group had fewer retries than the control group (1.3 ± 1.7 vs. - 1.1 ± 0.7, P = 0.006), and there was a tendency for fewer needle drops (0.4 ± 0.7 vs. - 0.5 ± 0.9, P = 0.06). The 3D annotation group scored significantly higher than the control group on the Global Evaluate Assessment of Robot Skills (16.8 ± 2.0 vs. 22.8 ± 2.4, P = 0.04). The 3D annotation group also scored higher than the voice (13.4 ± 1.2) and 2D annotation (16.2 ± 1.8) groups (3D vs. voice: P = 0.03, 3D vs. 2D: P = 0.03).

CONCLUSION

Telementoring using 3D drawing annotation was shown to provide good comprehension and a smooth operation for local surgeons.

Exploration of Malignant Characteristics in Neoadjuvant Chemotherapy-Resistant Rectal Cancer, Focusing on Extramural Lesions

BACKGROUND

Extramural vascular invasion (EMVI) and tumor deposits (TD) are poor prognostic factors in rectal cancer (RC), especially when resistant to neoadjuvant chemotherapy (NAC). We aimed to define differential expression in NAC responders and non-responders with concomitant EMVI and TD.

METHODS

From 52 RC surgical patients, post-NAC resected specimens were extracted, comprising two groups: cases with residual EMVI and TD (NAC-resistant) and cases without (NAC-effective). Proteomic analysis was conducted to define differential protein expression in the two groups. To validate the findings, immunohistochemistry was performed in another cohort that included 58 RC surgical patients. Based on the findings, chemosensitivity and prognosis were compared.

RESULTS

The NAC-resistant group was associated with a lower 3-year disease-free survival rate than the NAC-effective group (p = 0.041). Discriminative proteins in the NAC-resistant group were highly associated with the sulfur metabolism pathway. Among these pathway constituents, selenium-binding protein 1 (SELENBP1) expression in the NAC-resistant group decreased to less than one-third of that of the NAC-effective group. Immunohistochemistry in another RC cohort consistently validated the relationship between decreased SELENBP1 and poorer NAC sensitivity, in both pre-NAC biopsy and post-NAC surgery specimens. Furthermore, decrease in SELENBP1 was associated with a lower 3-year disease-free survival rate (p = 0.047).

CONCLUSIONS

We defined one of the differentially expressed proteins in NAC responders and non-responders, concomitant with EMVI and TD. SELENBP1 was suspected to contribute to NAC resistance and poor prognosis in RC.

Impact of antithrombotic therapy on postpancreatectomy hemorrhage in 7116 patients: A project study by the Japanese Society of Hepato-Biliary-Pancreatic Surgery

BACKGROUND

We previously reported an association between antithrombotic therapy and an increased risk of postpancreatectomy hemorrhage (PPH). To validate our findings, we conducted a large-scale multicenter retrospective study from 63 high-volume centers in Japan.

METHODS

Between 2015 and 2018, 7116 patients who underwent pancreatectomy were enrolled. The antithrombotic group consisted of 920 patients (12.9%) who received preoperative antithrombotic agents including aspirin, clopidogrel, ticlopidine, prasugrel, warfarin, and direct oral anticoagulants.

RESULTS

PPH occurred in 235 (3.3%) of the patients. The incidence of PPH and mortality were significantly higher in the antithrombotic group than in the control group (5.7 vs. 3.0% and 2.2 vs. 0.9%, respectively; both p < .001). In multivariate analysis, a history of antithrombotic use was an independent risk factor for grade C PPH (p = .036). In the antithrombotic group, PPH tended to be delayed in the patients with restarting antithrombotic therapy. Notably, the occurrence of delayed PPH after restarting antithrombotic therapy was observed only when antithrombotic therapy was restarted within 10 days after pancreatectomy.

CONCLUSIONS

This multicenter study demonstrated that a history of antithrombotic use was a significant risk factor for PPH and mortality. In particular, the resumption of antithrombotic therapy in the early postoperative period should be done with caution.

A case of hepaticojejunal anastomotic obstruction after a living-donor liver transplantation and recanalization using a high-frequency knife under the rendezvous technique

A 65-year-old woman underwent living-donor liver transplantation (left-lobe graft: GWRW ratio, 0.54) for cirrhosis caused by autoimmune hepatitis. At 68 years, she was diagnosed with obstructive cholangitis due to stricture during a hepaticojejunostomy following impaired liver function. Endoscopic balloon dilation of anastomosis and placement of a plastic stent resulted in improved liver function. However, at 72 years, the patient experienced a flare-up of liver damage. The plastic stent had fallen out, and although endoscopic stenotic dilation was attempted, the anastomotic site was obstructed completely. Therefore, recanalization of the hepaticojejunostomy was attempted using a rendezvous technique. A percutaneous transhepatic biliary drainage tube was inserted through the B3 bile duct, and the complete obstructed anastomosis was confirmed by percutaneous transhepatic and transjejunal approaches. The anastomosis was reopened by excising the scarred tissues from the jejunal side using a 1.5-mm high-frequency knife. A 14-Fr. catheter for the internal fistula tube was percutaneously placed at the opened anastomosis to achieve anastomotic site recanalization. The patient's liver damage improved after the re-internalization, and no symptom recurrence such as obstructive cholangitis developed for 1 year. There are few reports of recanalization of the hepaticojejunostomy with a high-frequency knife. Herein, we report the case with a literature review.

Dual epigenetic changes in diabetes mellitus-associated pancreatic ductal adenocarcinoma correlate with downregulation of E-cadherin and worsened prognosis

Diabetes mellitus (DM) is a risk factor for pancreatic ductal adenocarcinoma (PDAC) that promotes the promoter methylation of CDH1. It is still unclear whether DM can exert other epigenetic effects, such as altering microRNA (miR) expression, in PDAC. The expression of miR-100-5p is known to be changed in DM patients and can suppress the expression of E-cadherin. In this study, the correlation between DM status and dual epigenetic changes was evaluated in PDAC specimens from patients who underwent radical surgical resection. A total of 132 consecutive patients with PDAC were clinicopathologically evaluated. E-cadherin and nuclear β-catenin expression was measured using immunohistochemistry. DNA and miRs were extracted from the main tumor site on formalin-fixed paraffin-embedded tissue sections. TaqMan miR assays were applied to assess miR-100-5p expression. Bisulfite modification was conducted on the extracted DNA, which was then subjected to methylation-specific polymerase chain reaction. Immunohistochemistry revealed that decreased E-cadherin expression and increased nuclear β-catenin expression were significantly associated with DM and poor tumor cell differentiation. The presence of long-duration DM (≥3 years)  was a significant factor contributing to CDH1 promoter methylation (p < 0.01), while miR-100-5p expression was proportionally correlated with the preoperative HbA1c level (R = 0.34, p < 0.01), but not the duration of DM. The subjects with high miR-100-5p expression and CDH1 promoter methylation showed the highest level of vessel invasion and prevalence of tumor size ≥30 mm. PDAC subjects with dual epigenetic changes showed poorer overall survival (OS) than those with a single epigenetic change. miR-100-5p expression ≥4.13 and CDH1 promoter methylation independently predicted poor OS and disease-free survival (DFS) in the multivariate analysis. OS and DFS worsened in DM subjects with both HbA1c ≥ 6.5% and DM duration ≥3 years. Thus, DM is associated with two modes of epigenetic change by independent mechanisms and worsens prognosis.

A proposed new Japanese classification of synchronous peritoneal metastases from colorectal cancer: A multi-institutional, prospective, observational study conducted by the Japanese Society for Cancer of the Colon and Rectum

Aim

To establish a new Japanese classification of synchronous peritoneal metastases from colorectal cancer.

Methods

This multi-institutional, prospective, observational study enrolled patients who underwent surgery for colorectal cancer with synchronous peritoneal metastases. Overall survival rates were compared according to the various models using objective indicators. Each model was evaluated by Akaike's information criterion (AIC). The region of peritoneal metastases was evaluated by the peritoneal cancer index (PCI).

Results

Between October 2012 and December 2016, 150 patients were enrolled. The AIC of the present Japanese classification was 1020.7. P1 metastasis was defined as confined to two regions. The minimum AIC was obtained with the cutoff number of 10 or less for P2 metastasis and 11 or more for P3 metastasis. As for size, the best discrimination ability between P2 and P3 metastasis was obtained with a cutoff value of 3 cm. The AIC of the proposed classification was 1014.7. The classification was as follows: P0, no peritoneal metastases; P1, metastases localized to adjacent peritoneum (within two regions of PCI); P2, metastases to distant peritoneum, number ≤10 and size ≤3 cm; P3, metastases to distant peritoneum, number ≥11 or size >3 cm; P3a, metastases to distant peritoneum, number ≥11 and size ≤3 cm, or number ≤10 and size >3 cm; P3b, metastases to distant peritoneum, number ≥11 and size >3 cm.

Conclusion

This objective classification could improve the ability to discriminate prognosis in patients with synchronous peritoneal metastases from colorectal cancer.

Telesurgery and telesurgical support using a double-surgeon cockpit system allowing manipulation from two locations

BACKGROUND

Although several studies on telesurgery have been reported globally, a clinically applicable technique has not yet been developed. As part of a telesurgical study series conducted by the Japan Surgical Society, this study describes the first application of a double-surgeon cockpit system to telesurgery.

METHODS

Surgeon cockpits were installed at a local site and a remote site 140 km away. Three healthy pigs weighing between 26 and 29 kg were selected for surgery. Non-specialized surgeons performed emergency hemostasis, cholecystectomy, and renal vein ligation with remote assistance using the double-surgeon cockpits and specialized surgeons performed actual telesurgery. Additionally, the impact of adding internet protocol security (IPsec) encryption to the internet protocol-virtual private network (IP-VPN) line on communication was evaluated to address clinical security concerns.

RESULTS

The average time required for remote emergency hemostasis with the double-surgeon cockpit system was 10.64 s. A non-specialized surgeon could safely perform cholecystectomy or renal vein ligation with remote assistance. Global Evaluative Assessment of Robotic Skills and System Usability Scale scores were higher for telesurgical support-assisted surgery by a non-specialized surgeon using the double-surgeon cockpits than for telesurgery performed by a specialized surgeon without the double-cockpit system. Adding IPsec encryption to the IP-VPN did not have a significant impact on communication.

CONCLUSION

Telesurgical support through our double-surgeon cockpit system is feasible as first step toward clinical telesurgery.

Construction of redundant communications to enhance safety against communication interruptions during robotic remote surgery

It is important to ensure the redundancy of communication during remote surgery. The purpose of this study is to construct a communication system that does not affect the operation in the event of a communication failure during telesurgery. The hospitals were connected by two commercial lines, a main line and a backup line, with redundant encoder interfaces. The fiber optic network was constructed using both guaranteed and best-effort lines. The surgical robot used was from Riverfield Inc. During the observation, a random shutdown and restoration process of either line was conducted repeatedly. First, the effects of communication interruption were investigated. Next, we performed a surgical task using an artificial organ model. Finally, 12 experienced surgeons performed operations on actual pigs. Most of the surgeons did not feel the effects of the line interruption and restoration on still and moving images, in artificial organ tasks, and in pig surgery. During all 16 surgeries, a total of 175-line switches were performed, and 15 abnormalities were detected by the surgeons. However, there were no abnormalities that coincided with the line switching. It was possible to construct a system in which communication interruptions would not affect the surgery.

Three-dimensional analysis of perineural invasion in extrahepatic cholangiocarcinoma using tissue clearing

Perineural invasion (PNI) is a characteristic invasion pattern of distal cholangiocarcinoma (DCC). Conventional histopathologic examination is a challenging approach to analyze the spatial relationship between cancer and neural tissue in full-thickness bile duct specimens. Therefore, we used a tissue clearing method to examine PNI in DCC with three-dimensional (3D) structural analysis. The immunolabeling-enabled 3D imaging of solvent-cleared organs method was performed to examine 20 DCC specimens from five patients and 8 non-neoplastic bile duct specimens from two controls. The bile duct epithelium and neural tissue were labeled with CK19 and S100 antibodies, respectively. Two-dimensional hematoxylin/eosin staining revealed only PNI around thick nerve fibers in the deep layer of the bile duct, whereas PNI was not identified in the superficial layer. 3D analysis revealed that the parts of DCC closer to the mucosa exhibited more nerves than the normal bile duct. The nerve fibers were continuously branched and connected with thick nerve fibers in the deep layer of the bile duct. DCC formed a tubular structure invading from the epithelium and extending around thin nerve fibers in the superficial layer. DCC exhibited continuous infiltration around the thick nerve fibers in the deep layer. This is the first study using a tissue clearing method to examine the PNI of DCC, providing new insights into the underlying mechanisms.

Microanatomical organization of hepatic venous lymphatic system in humans

Lymphatic fluid drains from the liver via the periportal lymphatic, hepatic venous lymphatic, and superficial lymphatic systems. We performed a postmortem study to clarify the three-dimensional structure and flow dynamics of the human hepatic venous lymphatic system, as it still remains unclear. Livers were excised whole from three human cadavers, injected with India ink, and sliced into 1-cm sections from which veins were harvested. The distribution of lymphatic vessels was observed in 5 μm sections immunostained for lymphatic and vascular markers (podoplanin and CD31, respectively) using light microscopy. Continuity and density of lymphatic vessel distribution were assessed in en-face whole-mount preparations of veins using stereomicroscopy. The structure of the external hepatic vein wall was assessed with scanning electron microscopy (SEM). The lymphatic dynamics study suggested that lymphatic fluid flows through an extravascular pathway around the central and sublobular veins. A lymphatic vessel network originates in the wall of sublobular veins, with a diameter greater than 110 μm, and the peripheral portions of hepatic veins and continues to the inferior vena cava. The density distribution of lymphatic vessels is smallest in the peripheral portion of the hepatic vein (0.03%) and increases to the proximal portion (0.22%, p = 0.012) and the main trunk (1.01%, p < 0.001), correlating positively with increasing hepatic vein diameter (Rs = 0.67, p < 0.001). We revealed the three-dimensional structure of the human hepatic venous lymphatic system. The results could improve the understanding of lymphatic physiology and liver pathology.

Skeletal muscle mass and quality before preoperative chemotherapy influence postoperative long-term outcomes in esophageal squamous cell carcinoma patients

BACKGROUND

Previous reports have focused on muscle mass as a prognostic factor in esophageal cancer.

AIM

To investigate how preoperative body type influences the prognosis of patients with esophageal squamous cell carcinoma who underwent neoadjuvant chemotherapy (NAC) and surgery.

METHODS

The subjects were 131 patients with clinical stage II/III esophageal squamous cell carcinoma who underwent subtotal esophagectomy after NAC. Skeletal muscle mass and quality were calculated based on computed tomography images prior to NAC, and their statistical association with long-term outcomes was examined retrospectively in this case-control study.

RESULTS

The disease-free survival rates in the low psoas muscle mass index (PMI) group vs the high PMI group were 41.3% vs 58.8% (P = 0.036), respectively. In the high intramuscular adipose tissue content (IMAC) group vs the low IMAC group, the disease-free survival rates were 28.5% vs 57.6% (P = 0.021), respectively. The overall survival (OS) rates for the low PMI group vs the high PMI group were 41.3% vs 64.5% (P = 0.008), respectively, and for the high IMAC group vs the low IMAC group, they were 29.9% vs 61.9% (P = 0.024), respectively. Analysis of the OS rate revealed significant differences in patients aged 60 years or older (P = 0.018), those with pT3 or above disease (P = 0.021), or those with lymph node metastasis (P = 0.006), aside from PMI and IMAC. Multivariate analysis demonstrated that pT3 or above [hazard ratio (HR): 1.966, 95% confidence interval (CI): 1.089-3.550, P = 0.025), lymph node metastasis (HR: 2.154, 95%CI: 1.118-4.148, P = 0.022), low PMI (HR: 2.266, 95%CI: 1.282-4.006, P = 0.005), and high IMAC (HR: 2.089, 95%CI: 1.036-4.214, P = 0.022) were significant prognostic factors for esophageal squamous cell carcinoma.

CONCLUSION

Skeletal muscle mass and quality before NAC in patients with esophageal squamous cell carcinoma are significant prognostic factors for postoperative OS.

Use of time‑density curves of dynamic contrast‑enhanced computed tomography for determination of the histological therapeutic effects of neoadjuvant chemotherapy for pancreatic ductal adenocarcinoma

The present study aimed to investigate the histological changes caused by neoadjuvant chemotherapy (NAC) for pancreatic ductal adenocarcinoma (PDAC), and to demonstrate the use of time‑density curves (TDCs) of dynamic contrast‑enhanced computed tomography (CECT) for determination of the histological therapeutic effects of NAC for PDAC. A total of 96 patients with PDAC were examined; 46 underwent NAC (NAC group) and 50 did not undergo NAC (non‑NAC group). Based on histological therapeutic effect and using the area of residual tumor (ART) grading system, the NAC group was divided into low‑responders and high‑responders. Histological analysis was used to evaluate the densities of cancer cells, cancer‑associated fibroblasts (CAFs), microvessels and stromal collagen fibers in the NAC and non‑NAC groups. Radiological analysis was used to evaluate the TDCs of three slopes of the NAC group, namely slopes between the non‑contrast and arterial phases (δ1 and δ1'), between the arterial and portal phases (δ2 and δ2'), and between the portal and equilibrium phases (δ3 and δ3'). δ1‑δ3 were before NAC, whereas δ1'‑δ3' were after NAC. Changes in δ1, δ2 and δ3 before and after NAC were denoted as δδ1 (=δ1'‑δ1), δδ2 (=δ2'‑δ2) and δδ3 (=δ3'‑δ3). ART grading system, histological examination and radiological examination data were also statistically analyzed. Histological examination revealed a significant decrease in cancer cells and CAFs, and a significant increase in stromal collagen fibers due to NAC (P<0.01). Radiological examination revealed that δ1' was significantly higher than δ1 in low‑responders (P<0.05), whereas δ2' was significantly lower than δ2 in high‑responders (P<0.01). δδ2 was significantly lower and δδ3 was significantly higher in high‑responders than in low‑responders (P<0.01 and P<0.05, respectively). Receiver operating characteristic curve showed that δδ2 and δδ3 were effective indicators of the histological therapeutic effect of NAC. In conclusion, the TDC of dynamic CECT may be useful for determining the histological therapeutic effect of NAC for PDAC.

18F‑fluorodeoxyglucose positron emission tomography predicts recurrence and histological grade of extrahepatic bile duct cancer

Malignant tumors in cholangiocarcinoma are diagnosed and staged using ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) and clinical analysis. However, comprehensive analysis, including pathological analysis, has not yet been sufficiently performed. In the present study, the maximum standardized uptake value (SUVmax) was calculated using FDG-PET and its relationship with clinicopathological factors was analyzed. The present study included 86 patients who underwent preoperative FDG-PET/computed tomography (CT) and did not receive chemotherapy among 331 patients with hilar and distal cholangiocarcinoma. Receiver operating characteristic analysis with recurrence events was used to determine the SUVmax cutoff of 4.9. Immunohistochemical staining of glucose transporter 1 (Glut1), hypoxia-inducible factor-1α and Ki-67 was performed for pathological analysis. The standardized uptake value (SUV)-high group (SUVmax ≥4.9) had a higher postoperative recurrence rate (P<0.046) and higher Glut1 and Ki-67 expression rates (P<0.05 and P<0.0001, respectively). Furthermore, SUVmax and Glut1 expression (r=0.298; P<0.01) and SUVmax and Ki-67 expression rates (r=0.527; P<0.0001) were positively correlated. The preoperative measurement of SUVmax by PET-CT is useful in predicting recurrence as well as cancer malignancy.

[A Case of Long-Term Survival of Breast Cancer with Extra-Regional Lymph Node Metastases]

We present the case of a 65-year-old woman who presented with nipple retraction of her left breast. The patient has a family history of breast cancer. She was diagnosed with bilateral breast cancer with left axillary, cervical, and mediastinal lymph node metastasis(right breast cancer, cT1cN0M0, cStage Ⅰ, Luminal A-like, left breast cancer, cT2N3bM1[LYM], Stage Ⅳ, triple negative type). She was recommended chemotherapy due to her inoperable advanced-stage breast cancer. After 6 courses of administration of AC chemotherapy(doxorubicin and cyclophosphamide)and 5 courses of tri-weekly docetaxel chemotherapy, shrinkage of the primary lesion and disappearance of each swollen lymph node were observed via computed tomography. Surgery was performed 11 weeks post-chemotherapy. Residual lesions, less than 10 mm in size in both the left and right breast masses, were observed. No lymph node metastasis was observed. Four years later, no signs of recurrence have been noted.

[Short Term and Long Term Outcomes of Robotic Surgery in Sphincter Function Preserving Surgery for Lower Rectal Cancer]

BACKGROUND

Surgical and oncological outcomes of lower rectal cancer remain unsatisfactory. We investigated the short term and long term outcomes of robotic surgery for sphincter function-preserving surgery(SPS)for lower rectal cancer.

METHOD

433 lower rectal cancer patients who underwent SPS at our institution from January 2000 to July 2021 were included, excluding Stage Ⅳ cases and patients with multiple cancers. There were 288 cases of laparotomy, 81 cases of laparoscopic surgery, and 64 cases of robotic surgery; we abbreviated the group names as: OP, LAP, and R, respectively. We retrospectively reviewed the anastomotic leakage rate and prognosis of these groups.

RESULTS

The anastomotic leakage rate was 23.6% in the OP group, 17.3% in the LAP group, and 6.3% in the R group, with a significant difference between the OP group and the R group. The 3-year recurrence free survival rate was 86.7% in the LAP group and 95.6% in the R group. Although there was no significant difference, the prognosis tended to be better in the R group. Local recurrence was observed in 3 patients in the LAP group and 1 patient in the R group.

CONCLUSION

In SPS for advanced lower rectal cancer, robotic surgery may contribute to a reduction in anastomotic leakage.

Technical evaluation of robotic tele-cholecystectomy: a randomized single-blind controlled pilot study

Although robotic telesurgery is growing in popularity, the benefits of telesurgery compared to local surgery are unclear. This study aimed to evaluate the performance of robotic tele-cholecystectomy with a commercial line using the Saroa^™ (Riverfield, Inc., Tokyo, Japan) system. The operation rooms of the Hokkaido University Hospital and Kushiro City General Hospital were connected using a best effort-type line (1 Gbps), with a distance of 250 km between the two hospitals. In this experimental single-blind randomized crossover trial, eight expert robotic surgeons performed robotic cholecystectomy in an artificial organ model using the Saroa^™ system and were randomized to begin with either local surgery or telesurgery. All surgeons were assessed on task completion time, total path length of the right- and left- hand forceps and camera, Global Evaluative Assessment of Robotic Skills (GEARS), Global Operative Assessment of Laparoscopic Skills (GOALS), and System and Piper Fatigue Scale-12 (PFS-12). In all experiments, the communication environment was stable and the mean communication delay was 8 ms (3-31 ms). All tele-cholecystectomies were performed safely. There was no significant difference in completion time (P = 0.495), score of GEARS (P = 0.258), GOALS (P = 0.180), or PFS-12 (P = 0.528) between local surgery and telesurgery. The total path of the forceps tended to be longer in tele-cholecystectomy, particularly with significantly longer left-hand forceps total path length (P = 0.041). Robotic tele-cholecystectomy using a commercial line can be performed safely as same as local robotic surgery, but the total path of the left-hand forceps was prolonged in robotic tele-cholecystectomy due to overshoot. Therefore, a solution for overshooting will be required in the future.

Efficacy of chemotherapy for comorbid cancer in patients with simultaneous double cancers: a multicenter study

PURPOSE

Anticancer drugs for double cancers are selected based on their therapeutic effects on the target cancer, but there are insufficient data on the effects of anticancer drugs on comorbid cancer. We investigated the effect of chemotherapy on comorbid cancer in patients with simultaneous double cancers.

METHODS

The subjects of this retrospective study were 51 patients with simultaneous double cancers at the time of receiving systemic chemotherapy. We evaluated the types of anticancer drugs used for double cancers, the therapeutic effects on targeted and comorbid cancers, and prognoses.

RESULTS

Disease control was achieved for 90.9% of the target cancers and 90.7% of the comorbid cancers. The prognosis was significantly better when the disease was controlled, not only in the target cancer but also in the comorbid cancer.

CONCLUSION

Physicians treating double cancers should develop treatment strategies focusing not only on the treatment for advanced cancer, but also on the course of comorbidities and the therapeutic effects of anticancer drugs. This study is important because it presents new possibilities to expand the indications for anticancer drugs, while allowing unnecessary clinical research to be avoided.

Risk prediction model of peritoneal seeding in advanced gastric cancer: A decision tool for diagnostic laparoscopy

BACKGROUND

Selective diagnostic laparoscopy in gastric cancer patients at high risk of peritoneal metastasis is essential for optimal treatment planning. In this study available clinicopathologic factors predictive of peritoneal seeding in advanced gastric cancer (AGC) were identified, and this information was translated into a clinically useful tool.

METHODS

Totally 2833 patients underwent surgery for AGC between 2003 and 2013. The study identified clinicopathologic factors associated with the risk of peritoneal seeding for constructing nomograms using a multivariate logistic regression model with backward elimination. A nomogram was constructed to generate a numerical value indicating risk. Accuracy was validated using bootstrapping and cross-validation.

RESULTS

The proportion of seeding positive was 12.7% in females and 9.6% in males. Of 2833 patients who underwent surgery for AGC, 300 (10.6%) were intraoperatively identified with peritoneal seeding. Multivariate analysis revealed the following factors associated with peritoneal seeding: high American Society of Anesthesiologists score, fibrinogen, Borrmann type 3 or 4 tumors, the involvement of the middle, anterior, and greater curvature, cT3 or cT4cN1 or cN2 or cN3, cM1, and the presence of ascites or peritoneal thickening or plaque or a nodule on the peritoneal wall on computed tomography. The bootstrap analysis revealed a robust concordance between mean and final parameter estimates. The area under the ROC curve for the final model was 0.856 (95% CI, 0.835-0.877), which implies good performance.

CONCLUSIONS

This nomogram provides effective risk estimates of peritoneal seeding from gastric cancer and can facilitate individualized decision-making regarding the selective use of diagnostic laparoscopy.

Verification of delay time and image compression thresholds for telesurgery

INTRODUCTION

Telerobotic surgery relies on communication lines, causing delays, and video information requires pre-transmission compression. Such delays and video degradation will continue to be unavoidable making communication conditions verification essential. Understanding the network specification values required for telerobotic surgery entails determining acceptable levels of delay and degradation due to the video compression and restoration processes during surgery.

METHODS

The hinotori™ surgical robot from Medicaroid was used. Eight surgeons, skilled in robotic surgery, performed gastrectomy or rectal resection on pigs. Image compression (bitrate: 120, 60, 30, 20, 10 Mbps) was random, changing encoder settings during surgery, and delay times (30, 50, 100, 150 milliseconds) were pseudo-randomly inserted, changing emulator settings. Acceptable video levels were evaluated. Subjective evaluations by surgeons and evaluators regarding image degradation and operability, and objective evaluations of image degradation and operability were given five-point ratings.

RESULTS

Regarding delay time, 30 and 50 millisecond periods garnered average ratings of 3.6 and 4.0, respectively, signifying that surgery was feasible. However, at 100 and 150 millisecond, average ratings were 2.9 and 2.3, respectively, indicating surgery was not feasible for the most part in these cases. The average rating for image compression was 4.0 or higher for bitrates of 20, 30, 60, and 120 Mbps, suggesting that surgery is possible even at bitrates as low as 10 Mbps, with an average rating of 4.0.

CONCLUSION

In remote robotic surgery using the hinotori™, image compression and delay time are largely acceptable, so surgery can be safely performed.

Diabetes mellitus impacts on expression of DNA mismatch repair protein PMS2 and tumor microenvironment in pancreatic ductal adenocarcinoma

AIMS/INTRODUCTION

The mismatch repair (MMR) protein recognizes DNA replication errors and plays an important role in tumorigenesis, including pancreatic ductal adenocarcinoma (PDAC). Although PMS2, a MMR protein, is degraded under oxidative stress, the effects of diabetes are still unclear. Herein, we focused on whether diabetes affected MMR protein expression in PDAC.

MATERIALS AND METHODS

Tissues from 61 surgically resected PDAC subjects were clinicopathologically analyzed. Immunohistochemical analysis was performed for MMR protein expression, oxidative stress, and immune cell infiltration. The change of MMR protein expression was assessed in PDAC cell lines under stimulation with 25 mM glucose and 500 μM palmitic acid. Survival curves were analyzed by the Kaplan-Meier method with the log-rank test.

RESULTS

Diabetes complicated with dyslipidemia significantly decreased the expression of PMS2 in PDAC tissues with an inverse correlation with the degree of oxidative stress. Palmitic acid combined with high glucose induced degradation of PMS2 protein, enhancing oxidative stress in vitro. CD8⁺ T-cell infiltration was associated with a short duration of type 2 diabetes (≤4 years) and a low expression of PMS2 in PDAC tissues, while CD163⁺ tumor-associated macrophage infiltration was increased with a long duration of diabetes (>4 years). A short duration of diabetes exhibited a better prognosis than nondiabetic subjects with PDAC (P < 0.05), while a long duration of diabetes had a worse prognosis (P < 0.05).

CONCLUSIONS

The different phases of diabetes have a major impact on PDAC by altering PMS2 expression and the tumor immune microenvironment, which can be targeted by an immune checkpoint inhibitor.

Maximum acceptable communication delay for the realization of telesurgery

AIM

To determine acceptable limits of communication delays in telesurgery, we investigated the impact of communication delays under a dynamic environment using a surgical assist robot. Previous studies have evaluated acceptable delays under static environments. Effects of delays may be enhanced in dynamic environments, but studies have not yet focused on this point.

METHODS

Thirty-four subjects with different surgical experience (Group1: no surgical experience; Group2: only laparoscopic surgical experience; Group3: robotic surgery experience) performed 4 tasks under different delays (0, 70, 100, 150, 200, or 300 ms) using a surgical assist robot. Task accomplishment time and total movement distance of forceps were recorded and compared under different communication delays of 0-300 ms. In addition, surgical performance was compared between Group1or Group2 without delay and Group3 with communication delays.

RESULTS

Significant differences in task accomplishment time were found between delays of 0 and 70 ms, but not between delays of 70 and 100 ms. Thereafter, the greater the communication delay, the longer the task accomplishment time. Similar results were obtained in total movement distance of forceps. Comparisons between Group3 with delay and Group1 or Group2 without delay demonstrated that surgical performance in Group3 with delay was superior or equal to that of Group1 or Group2 without delay as long as the delay was 100 ms or less.

CONCLUSIONS

Communication delays in telesurgery may be acceptable if 100 ms or less. Experienced surgeons with more than 100 ms of delay could outperform less-experienced surgeons without delay.

Heterogeneity of metabolic adaptive capacity affects the prognosis among pancreatic ductal adenocarcinomas

BACKGROUND

Evolutionary cancer has a supply mechanism to satisfy higher energy demands even in poor-nutrient conditions. Metabolic reprogramming is essential to supply sufficient energy. The relationship between metabolic reprogramming and the clinical course of pancreatic ductal adenocarcinoma (PDAC) remains unclear. We aimed to clarify the differences in metabolic status among PDAC patients.

METHODS

We collected clinical data from 128 cases of resectable PDAC patients undergoing surgery. Sixty-three resected tissues, 15 tissues from the low carbohydrate antigen 19-9 (CA19-9), 38-100 U/mL, and high CA19-9, > 500 U/mL groups, and 33 non-tumor control parts, were subjected to tandem mass spectrometry workflow to systematically explore metabolic status. Clinical and proteomic data were compared on the most used PDAC biomarker, preoperative CA19-9 value.

RESULTS

Higher CA19-9 levels were clearly associated with higher early recurrence (p < 0.001), decreased RFS (p < 0.001), and decreased DSS (p = 0.025). From proteomic analysis, we discovered that cancer evolution-related as well as various metabolism-related pathways were more notable in the high group. Using resected tissue immunohistochemical staining, we learned that high CA19-9 PDAC demonstrated aerobic glycolysis enhancement, yet no decrease in protein synthesis. We found a heterogeneity of various metabolic processes, including carbohydrates, proteins, amino acids, lipids, and nucleic acids, between the low and the high groups, suggesting differences in metabolic adaptive capacity.

CONCLUSIONS

Our study found metabolic adaptation differences among PDAC cases, pertaining to both cancer evolution and the prognosis. CA19-9 can help estimate the metabolic adaptive capacity of energy supply for PDAC evolution.

Necrotizing pancreatitis complicated by retroperitoneal emphysema: two case reports

Background

Emphysematous pancreatitis is acute pancreatitis associated with emphysema based on imaging studies and has been considered a subtype of necrotizing pancreatitis. Although some recent studies have reported the successful use of conservative treatment, it is still considered a serious condition. Computed tomography (CT) scan is useful in identifying emphysema associated with acute pancreatitis; however, whether the presence of emphysema correlates with the severity of pancreatitis remains controversial. In this study, we managed two cases of severe acute pancreatitis complicated with retroperitoneal emphysema successfully by treatment with lavage and drainage.

Case presentation

Case 1: A 76-year-old man was referred to our hospital after being diagnosed with acute pancreatitis. At post-admission, his abdominal symptoms worsened, and a repeat CT scan revealed increased retroperitoneal gas. Due to the high risk for gastrointestinal tract perforation, emergent laparotomy was performed. Fat necrosis was observed on the anterior surface of the pancreas, and a diagnosis of acute necrotizing pancreatitis with retroperitoneal emphysema was made. Thus, retroperitoneal drainage was performed. Case 2: A 50-year-old woman developed anaphylactic shock during the induction of general anesthesia for lumbar spine surgery, and peritoneal irritation symptoms and hypotension occurred on the same day. Contrast-enhanced CT scan showed necrotic changes in the pancreatic body and emphysema surrounding the pancreas. Therefore, she was diagnosed with acute necrotizing pancreatitis with retroperitoneal emphysema, and retroperitoneal cavity lavage and drainage were performed. In the second case, the intraperitoneal abscess occurred postoperatively, requiring time for drainage treatment. Both patients showed no significant postoperative course problems and were discharged on postoperative days 18 and 108, respectively.

Conclusion

Acute pancreatitis with emphysema from the acute phase highly indicates severe necrotizing pancreatitis. Surgical drainage should be chosen without hesitation in necrotizing pancreatitis with emphysema from early onset.

The diversity and abundance of gut microbiota are associated with the pain sensation threshold in the Japanese population

Small fibre neuropathy (SFN) is an initial pathology of diabetic polyneuropathy (DPN). Serum lipopolysaccharide binding protein levels are positively correlated with the pain threshold in the foot, suggesting that the abundance of gut Gram-negative bacilli, which are a source of lipopolysaccharides, may be involved in the development of DPN. Furthermore, the abundance of the gut and oral microbiota is assumed to be involved in the pathogenesis of diabetes. Nevertheless, the association between SFN and the microbiota has not been clarified. A total of 1056 individuals were recruited in the 2018 Iwaki Health Promotion Project. Pain sensation was evaluated based on the pain threshold from intraepidermal electrical stimulation (PINT). Patients with PINT scores <0.15 mA were categorized into the low-PINT group (n = 718); otherwise, they were categorized into the high-PINT group (n = 283). Furthermore, each group was divided into the subjects with or without glucose tolerance based on HbA1c levels, fasting blood glucose levels and diabetic history. Principal coordinate analysis and α- and β-diversity of the microbiota were evaluated. The correlation between clinical and microbiota data was examined. Oral microbiota diversity showed no structural differences according to PINT scores, whereas principal coordinate analysis and α- and β-diversity revealed significant structural differences in gut microbiota (p < 0.01, p < 0.05 and p < 0.05, respectively), even after the participants with glucose intolerance were excluded (p < 0.01, p < 0.05 and p < 0.05, respectively). The relative abundance of the genus Bacteroides was significantly lower in high-PINT participants compared with low-PINT participants (10 ± 6.7% vs. 11.3 ± 7.0%, p < 0.01), even after the exclusion of subjects with diabetes and impaired fasting glucose (10.0 ± 6.5% vs. 11.2 ± 6.9%, p < 0.05). In univariate linear regression analyses, PINT was significantly correlated with metabolic syndrome parameters, eGFR, uric acid level and the abundance of Bacteroides. The correlation between Bacteroides and PINT scores remained significant after adjustment for multiple factors (β = -0.07181, p < 0.05). Changes of bacterial diversity and a low abundance of gut Bacteroides were correlated with elevated PINT scores in the Japanese population. This correlation may represent a new therapeutic option for SFN.

Reappraisal of telesurgery in the era of high-speed, high-bandwidth, secure communications: Evaluation of surgical performance in local and remote environments

Aim

Communication and video transmission delays negatively affect telerobotic surgery. Since latency varies by communication environment and robot, to realize remote surgery, both must perform well. This study aims to examine the feasibility of telerobotic surgery by validating the communication environment and local/remote robot operation, using secure commercial lines and newly developed robots.

Methods

Hirosaki University and Mutsu General Hospital, 150 km apart, were connected via a Medicaroid surgical robot. Ten surgeons performed a simple task remotely using information encoding and decoding. The required bandwidth, delay time, task completion time, number of errors, and image quality were evaluated. Next, 11 surgeons performed a complex task using gallbladder and intestinal models in local/remote environments; round trip time (RTT), packet loss, time to completion, operator fatigue, operability, and image were observed locally and remotely.

Results

Image quality was not so degraded as to affect remote robot operation. Median RTT was 4 msec (2-12), and added delay was 29 msec. There was no significant difference in accuracy or number of errors for cholecystectomy, intestinal suturing, completion time, surgeon fatigue, or image evaluation.

Conclusion

The fact that remote surgery succeeded equally to local surgery showed that this system has the necessary elemental technology for widespread social implementation.

Short-term outcomes of robotic-assisted surgery following neoadjuvant chemotherapy for lower rectal cancer

INTRODUCTION

There have been reports about robotic surgery for rectal cancer with chemoradiotherapy (CRT), but only a few studies have compared the use of robotic surgery with and without neoadjuvant chemotherapy (NAC). The aim of our study was to compare the perioperative outcomes of robotic surgery with and without NAC for lower rectal cancer and to examine the effects of NAC on robotic surgery.

METHODS

From January 2016 to July 2021, we compared the short-term outcomes of 45 patients who did not undergo NAC and 55 patients who underwent NAC.

RESULTS

The rate of sphincter-preserving surgeries was higher in the NAC group than in the non-NAC group (P = .024). The total operative time was significantly longer in the NAC group than in the non-NAC group (P < .001). The rate of lateral lymph node dissection was significantly higher in the NAC group than in the non-NAC group (P < .001). No significant differences were identified in the rate of incisional surgical site infections (SSI), organ/space SSI postoperative bleeding, small bowel obstruction, anastomotic leakage, urinary dysfunction, or urinary infections between the groups. There were eight incidences of lateral lymph node metastasis (15%) and two cases with positive resection margins (4.0%) in the NAC group.

CONCLUSIONS

Robotic surgery after NAC has few complications and a higher sphincter-preserving rate that without NAC.

Impact of the suboptimal communication network environment on telerobotic surgery performance and surgeon fatigue

Background

Remote surgery social implementation necessitates achieving low latency and highly reliable video/operation signal transmission over economical commercial networks. However, with commercial lines, communication bandwidth often fluctuates with network congestion and interference from narrowband lines acting as bottlenecks. Therefore, verifying the effects on surgical performance and surgeon fatigue when communication lines dip below required bandwidths are important.

Objectives

To clarify the communication bandwidth environment effects on image transmission and operability when bandwidth is lower than surgical robot requirements, and to determine surgeon fatigue levels in suboptimal environments.

Methods

Employing a newly developed surgical robot, a commercial IP-VPN line connected two hospitals 150 km apart. Thirteen surgical residents remotely performed a defined suturing procedure at 1-Gbps to 3-Mbps bandwidths. Communication delay, packet loss, time-to-task completion, forceps-movement distance, video degradation, and robot operability were evaluated before and after bandwidth changes. The Piper Fatigue Score-12 (PFS-12) was used to measure fatigue associated with surgeon performance.

Results

Roundtrip communication time for both 1-Gbps and 3-Mbps lines averaged 4 ms. Video transmission delay from camera to monitor was comparable, at 92 ms. Surgical robot signal transmission rate averaged 5.2 Mbps, so changing to 1-Gbps-3-Mbps lines resulted in significant packet loss. Surgeons perceived significant roughness, image distortion, diplopia, and degradation of 3D images (p = 0.009), but not changes in delay time or maneuverability. All surgeons could complete tasks, but objective measurement of task-completion time and forceps-travel distance were significantly prolonged (p = 0.013, p = 0,041). Additionally, PFS-12 showed post-procedure fatigue increase at both 1-Gbps and 3-Mbps. Fatigue increase was significant at 3-Mbps (p = 0.041).

Conclusions

In remote surgery environments with less than the optimal bandwidth, even when delay time and operability are equivalent, reduced surgical performance occurs from video degradation from packet loss. This may cause increased surgeon fatigue.

Differential diagnoses of gallbladder tumors using CT‐based deep learning

Background

The differential diagnosis between gallbladder cancer (GBC) and xanthogranulomatous cholecystitis (XGC) remains quite challenging, and can possibly lead to improper surgery. This study aimed to distinguish between XGC and GBC by combining computed tomography (CT) images and deep learning (DL) to maximize the therapeutic success of surgery.

Methods

We collected a dataset, including preoperative CT images, from 28 cases of GBC and 21 XGC patients undergoing surgery at our facility. It was subdivided into training and validation (n = 40), and test (n = 9) datasets. We built a CT patch‐based discriminating model using a residual convolutional neural network and employed 5‐fold cross‐validation. The discriminating performance of the model was analyzed in the test dataset.

Results

Of the 40 patients in the training dataset, GBC and XGC were observed in 21 (52.5%), and 19 (47.5%) patients, respectively. A total of 61 126 patches were extracted from the 40 patients. In the validation dataset, the average sensitivity, specificity, and accuracy were 98.8%, 98.0%, and 98.5%, respectively. Furthermore, the area under the receiver operating characteristic curve (AUC) was 0.9985. In the test dataset, which included 11 738 patches, the discriminating accuracy for GBC patients after neoadjuvant chemotherapy (NAC) (n = 3) was insufficient (61.8%). However, the discriminating model demonstrated high accuracy (98.2%) and AUC (0.9893) for cases other than those receiving NAC.

Conclusion

Our CT‐based DL model exhibited high discriminating performance in patients with GBC and XGC. Our study proposes a novel concept for selecting the appropriate procedure and avoiding unnecessary invasive measures.

[Treatment Strategy for Stage Ⅳ Rectal Cancer Considering Local Treatment Outcomes]

We investigated 36 patients with Stage Ⅳ rectal cancer who underwent primary resection in our department between November 2015 and June 2020. Tumor localization was upper in 20 cases and lower in 16 cases. Six patients had the cT4b stage at initial diagnosis, and lateral lymph node metastases were detected in 6 cases. Preoperative treatment consisted of doublet chemotherapy in 20 cases, in combination with bevacizumab in 17 cases. Surgery for distant metastases was performed in 21 patients, and the final results were curative(Cur B)in 20 patients and palliative(Cur C)in 16 patients. Perioperative mortality was observed only in Cur C patients(5.6%). The local R1 resection rates in Cur B and Cur C patients were 10.0% and 18.8%, respectively, and the corresponding local RM≤1 mm rates were 55.0% and 43.8%. Additionally, the local recurrence rates were 25.0% and 0%, and the 3-year OS rates were 80.9% and 25.5%, respectively, in Cur B and Cur C patients. In Cur B, the local RM≤1 mm rates in the preoperative and non-preoperative treatment groups were 38.5% and 85.7%, respectively, and the corresponding local R1 resection rates were 7.7% and 14.3%. Additionally, the 3-year local recurrence-free survival rates were 68.2% and 66.7% and the 3-year OS rates were 82.1% and 80.0%, respectively, in the preoperative and non-preoperative treatment groups. We determined that preoperative chemotherapy alone is not sufficient for the local treatment of Stage Ⅳ rectal cancer, and concomitant preoperative radiotherapy should be considered. The prognosis of patients with Cur C is poor, and surgery-related deaths have been observed, which can be a problem for the palliative resection strategy.

CT-based deep learning enables early postoperative recurrence prediction for intrahepatic cholangiocarcinoma

Preoperatively accurate evaluation of risk for early postoperative recurrence contributes to maximizing the therapeutic success for intrahepatic cholangiocarcinoma (iCCA) patients. This study aimed to investigate the potential of deep learning (DL) algorithms for predicting postoperative early recurrence through the use of preoperative images. We collected the dataset, including preoperative plain computed tomography (CT) images, from 41 patients undergoing curative surgery for iCCA at multiple institutions. We built a CT patch-based predictive model using a residual convolutional neural network and used fivefold cross-validation. The prediction accuracy of the model was analyzed. We defined early recurrence as recurrence within a year after surgical resection. Of the 41 patients, early recurrence was observed in 20 (48.8%). A total of 71,081 patches were extracted from the entire segmented tumor area of each patient. The average accuracy of the ResNet model for predicting early recurrence was 98.2% for the training dataset. In the validation dataset, the average sensitivity, specificity, and accuracy were 97.8%, 94.0%, and 96.5%, respectively. Furthermore, the area under the receiver operating characteristic curve was 0.994. Our CT-based DL model exhibited high predictive performance in projecting postoperative early recurrence, proposing a novel insight into iCCA management.