Clinical practice guidelines for telesurgery 2022 : Committee for the promotion of remote surgery implementation, Japan Surgical Society.

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.

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.

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.

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.

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.

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.

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.

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.

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.

[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.

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.

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.

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.

[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.

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.

[Treatment Strategy for Stage â £ 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.

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.

Tele-assessment of bandwidth limitation for remote robotics surgery.

PURPOSE: We investigated the communication bandwidth (CB) limitation for remote robotics surgery (RRS) using hinotori™ (Medicaroid, Kobe, Japan). METHODS: The 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). RESULTS: Packet 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. CONCLUSION: Our 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.