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PurposeWe investigated the communication bandwidth (CB) limitation for remote robotics surgery (RRS) using hinotori™ (Medicaroid, Kobe, Japan).MethodsThe operating rooms of the Hokkaido University Hospital and Kyushu University Hospital were connected using the Science Information NETwork (SINET). The minimum required CB for the RRS was verified by decreasing the CB from 500 to 100 Mbps. Ten surgeons were tested on a task (intracorporeal suturing) at different levels of video compression (VC) (VC1: 120 Mbps, VC2: 40 Mbps, VC3: 20 Mbps) with the minimum required CB, and assessed based on the task completion time, Global Evaluative Assessment of Robotic Skills (GEARS), and System and Piper Fatigue Scale-12 (PFS-12).ResultsPacket loss was observed at 3–7% and image degradation was observed at 145 Mbps CB. The task performance with VC1 was significantly worse than that with VC2 and VC3 according to the task completion time (VC1 vs VC2, P = 0.032; VC1 vs. VC3, P = 0.032), GEARS (VC1 vs VC2; P = 0.029, VC1 vs VC3; P = 0.031), and PFS-12 (VC1 vs. VC2; P = 0.032, VC1 vs. VC3; P = 0.032) with 145 Mbps.ConclusionOur findings provide evidence that RRS using hinotori™ requires a CB ≥ 150 Mbps. We also found that when there is insufficient CB, RRS can be continued by compressing the image.

The efficacy of preoperative neoadjuvant chemoradiotherapy (NAC) in cases of pancreatic cancer with extremely poor prognoses has been reported. In this study, we aimed to identify novel biomarkers that reflect prognoses following chemoradiotherapy using tertiary lymphoid organs (TLO) expressed in the tumor microenvironment. Resected tumor specimens were obtained from 140 pancreatic cancer patients. We retrospectively investigated the clinical relevance of TLO by categorizing patients into those who underwent upfront surgery (surgery first [SF]) and those who received NAC. The immunological elements within TLO were analyzed by immunohistochemistry (IHC). In the IHC analysis, the proportions of CD8+ T lymphocytes, PNAd+ high endothelial venules, CD163+ macrophages and Ki‐67+ cells within the TLO were higher in the NAC group than in the SF group. In contrast, the proportion of programmed cell death‐1+ immunosuppressive lymphocytes within TLO was lower in the NAC group than in the SF group. The NAC group demonstrated favorable prognoses compared with the SF group. In the multivariate analysis, the TLO/tumor ratio was determined as an independent predictive prognostic factor. In conclusion, the administration of preoperative chemoradiotherapy may influence the immunological elements in the tumor microenvironment and result in favorable prognoses in pancreatic ductal adenocarcinoma patients. The administration of preoperative chemoradiotherapy may influence the immunological elements in the tumor microenvironment and result in favorable prognoses in pancreatic ductal adenocarcinoma patients.

PurposeIn recent years, the expectations for telesurgery have grown with the development of robot-assisted surgical technology and advances in communication technology. To verify the feasibility of the social implementation of telesurgery, we evaluated the communication integrity, availability, and communication delay of robotic surgery by remote control under different communication conditions of commercial lines.MethodsA commercial line was used to connect hospitals 150 km apart. We had prepared guaranteed-type lines (1Gbps, 10Mbps, 5Mbps) and best effort-type lines. Two types of robotic teleoperations were performed, and we evaluated the round-trip time (RTT) of communication, packet loss, and glass-to-glass time.ResultsThe communication delay was 4 ms for the guaranteed-type line and 10 ms for the best effort-type line. Packet loss occurred on the 5 Mbps guaranteed-type line. The mean glass-to-glass time was 92 ms for the guaranteed-type line and 95 ms for the best effort-type line. There was no significant difference in the number of errors in the task according to the type of line or the bandwidth speed.ConclusionsThe social implementation of telesurgery using the currently available commercial communication network is feasible.

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. 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. 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. 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). 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.

INTRODUCTION: In laparoscopic gastrectomy, accurate marking of the lesion site is essential in determining the resection line of the stomach, owing to the lack of haptics and the direct link between negative pathological margins and prognosis. Intraoperative endoscopy may require personnel and prolong the operation time, whereas preoperative endoscopic tattooing using India ink faces problems related to the spread of ink and visibility. ZEOCLIP FS (Zeon Medical, Tokyo, Japan) is a clip made of fluorescent resin, covered by insurance since March 2019. It can be visualized from the serosal side using a near-infrared scope; however, its weak fluorescence intensity often poses viewing difficulties. Lumifinder (ADVANTEST, Tokyo, Japan) is a laparoscopic fluorescence spectrum system available for clinical use since February 2023. It can measure fluorescence intensity using a near-infrared laser and detect weak fluorescent signals. We report a case of gastric cancer in which the location of the lesion was confirmed intraoperatively using ZEOCLIP FS and Lumifinder.CASE PRESENTATION: A man in his 80s was diagnosed with gastric cancer following an examination for anemia. Two lesions were found: a 0-IIc type (cT1) at the lesser curvature of the gastric angle and a type 1 tumor (cT2) at the anterior wall of the upper gastric body. The preoperative assessment indicated no lymph node or distant metastasis. The tumor was diagnosed as cStage I and laparoscopic distal gastrectomy was planned. Two ZEOCLIP FS clips were placed on the oral side of the tumor on the anterior wall of the upper gastric body on the day before surgery. During surgery, fluorescent signals from the clips were detected using Lumifinder, enabling easy confirmation of the lesion location and determination of the gastric resection line.CONCLUSIONS: The combined use of ZEOCLIP FS and Lumifinder was a useful new method for identifying the appropriate resection line of the stomach. We plan to evaluate this method further in additional cases to enhance the detection efficacy.

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.

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.

Telesurgery is expected to improve medical access in areas with limited resources, facilitate the rapid dissemination of new surgical procedures, and advance surgical education. While previously hindered by communication delays and costs, recent advancements in information technology and the emergence of new surgical robots have created an environment conducive to societal implementation. In Japan, the legal framework established in 2019 allows for remote surgical support under the supervision of an actual surgeon. The Japan Surgical Society led a collaborative effort, involving various stakeholders, to conduct social verification experiments using telesurgery, resulting in the development of a Japanese version of the “Telesurgery Guidelines” in June 2022. These guidelines outline requirements for medical teams, communication environments, robotic systems, and security measures for communication lines, as well as responsibility allocation, cost burden, and the handling of adverse events during telesurgery. In addition, they address telementoring and full telesurgery. The guidelines are expected to be revised as needed, based on the utilization of telesurgery, advancements in surgical robots, and improvements in information technology.

Photodynamic diagnosis/therapy (PDD/PDT) are novel modalities for the diagnosis and treatment of cancer. The photosensitizer protoporphyrin IX is metabolized from 5-aminolevulinic acid (5-ALA) intracellularly, and PDD/PDT using 5-ALA have been approved in dermatologic malignancies and gliomas. However, the molecular mechanism that defines the efficacy of PDD/PDT is unknown. In this study, we analyzed the functions of ATP-binding cassette (ABC) transporters in PDD using 5-ALA. Most of the human gastrointestinal cancer line cells examined showed a homogenous staining pattern with 5-ALA, except for the pancreatic cancer line PANC-1, which showed heterogeneous staining. To analyze this heterogeneous staining pattern, single cell clones were established from PANC-1 cells and the expression of ABC transporters was assessed. Among the ABC transporter genes examined, ABCG2 showed an inverse correlation with the rate of 5-ALA-positive staining. PANC-1 clone #2 cells showed the highest level of ABCG2 expression and the lowest level of 5-ALA staining, with only a 0.6% positive rate. Knockdown of the ABCG2 gene by small interfering RNAs increased the positive rate of 5-ALA staining in PANC-1 wild-type and clone cells. Interestingly, PANC-1 clone #2 cells showed the high sphere-forming ability and tumor-formation ability, indicating that the cells contained high numbers of cancer stem cells (CSCs). Knockdown or inhibition of ABCG2 increased the rate of 5-ALA staining, but did not decrease sphere-forming ability. These results indicate that gastrointestinal cancer cell lines expressing high levels of ABCG2 are enriched with CSCs and show low rates of 5-ALA staining, but 5-ALA staining rates can be improved by inhibition of ABCG2.

BackgroundThe differences between perihilar cholangiocarcinoma (PHCC) and distal cholangiocarcinoma (DCC) regarding recurrence and the factors that affect recurrence after surgery are unclear. This study aims to investigate the differences in recurrence patterns between patients with PHCC and those with DCC after surgical resection with curative intent. It also investigates the risk factors associated with recurrence and survival thereafter.Patients and MethodsThe postoperative courses of 366 patients with extrahepatic cholangiocarcinomas (EHCCs), including 236 with PHCC and 130 with DCC, who underwent surgical resections were investigated retrospectively.ResultsDuring follow-up, tumors recurred in 143 (60.6%) patients with PHCC and in 72 (55.4%) patients with DCC. Overall survival (OS) after surgery, recurrence-free survival (RFS), and OS after recurrence were similar for the patients with PHCC and those with DCC. The cumulative probability of recurrence declined 3 years after surgery in the patients with PHCC and those with DCC. A multivariable analysis determined that, among the patients with PHCC and those with DCC, regional lymph node metastasis was a significant risk factor associated with RFS. Ten patients with PHCC and eight patients with DCC with two or fewer sites of recurrence in a single organ underwent resections. A multivariable analysis determined that recurrent tumor resection was an independent prognostic factor associated with OS after recurrence in the patients with PHCC and those with DCC.ConclusionsPostoperative survival did not differ between the patients with PHCC and those with DCC. Frequent surveillances for recurrence are needed for 3 years after surgical resection of EHCCs. In selected patients, surgery for recurrent EHCCs might be associated with improved outcomes.