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.

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.

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.

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.

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.

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.

[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.

[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 Prospective Multicenter Phase II Study on the Feasibility and Efficacy of S-1 and Oxaliplatin Neoadjuvant Chemotherapy for Locally Advanced Rectal Cancer.

BACKGROUND: Neoadjuvant chemoradiotherapy and total mesorectal excision compose the standard of care for rectal cancer in multiple guidelines. However, neoadjuvant chemoradiotherapy has not exhibited clear survival benefits but rather has led to an increase in adverse events. Conversely, neoadjuvant chemotherapy is expected to prevent adverse events caused by radiation, yet this treatment is still controversial. OBJECTIVE: The purpose of this study was to evaluate the feasibility and efficacy of S-1 and oxaliplatin neoadjuvant chemotherapy together with total mesorectal excision for resectable locally advanced rectal cancer. DESIGN: The study was a prospective, single-arm phase II trial. SETTINGS: The study was conducted at multiple institutions. PATIENTS: Fifty-eight patients with resectable locally advanced rectal cancer were enrolled. INTERVENTION: Three cycles of S-1 and oxaliplatin were administered before surgery. S-1 was administered orally at 80 mg/m2 per day for 14 consecutive days, followed by a 7-day resting period. Oxaliplatin was given intravenously on the first day at a dose of 130 mg/m2 per day. The duration of 1 cycle was considered to be 21 days. Total mesorectal excision with bilateral lymph node dissection was carried out after neoadjuvant chemotherapy. MAIN OUTCOME MEASURES: The study was designed to detect the feasibility and efficacy of S-1 and oxaliplatin as neoadjuvant chemotherapy. RESULTS: The completion rate of 3 courses of S-1 and oxaliplatin as neoadjuvant chemotherapy was 94.8% (55/58). The reasons for discontinuation were thrombocytopenia (3.4%) and liver injury (1.7%). The most common severe (grade ≥3) adverse effect of neoadjuvant chemotherapy was thrombocytopenia (3.4%). There were no severe adverse clinical symptoms. Consequently, R0 resection was achieved in 51 (98.1%) of 52 patients. Pathologic complete response occurred in 10 patients (19.2%). LIMITATIONS: This was a single-arm, nonrandomized phase II study. CONCLUSIONS: The combination of S-1 and oxaliplatin neoadjuvant chemotherapy and total mesorectal excision is a feasible and promising treatment option for resectable locally advanced rectal cancer. See Video Abstract at http://links.lww.com/DCR/B555. UN ESTUDIO PROSPECTIVO MULTICNTRICO FASE II SOBRE LA FACTIBILIDAD Y EFICACIA DE LA QUIMIOTERAPIA NEOADYUVANTE SCON OXALIPLATINO PARA EL CNCER DE RECTO LOCALMENTE AVANZADO: ANTECEDENTES:La quimiorradioterapia neoadyuvante y la escisión mesorrectal total constituyen el estándar de atención para el cáncer de recto en varias guías. Sin embargo, la quimiorradioterapia neoadyuvante no ha mostrado beneficios claros en la sobrevida, pero si ha creado un aumento de eventos adversos. Por otro lado, se espera que la quimioterapia neoadyuvante prevenga los eventos adversos asociados a la radiación, aunque este tratamiento sigue siendo controvertido.OBJETIVO:Evaluar la factibilidad y eficacia de la quimioterapia neoadyuvante S-1 con oxaliplatino en conjunto con la escisión mesorrectal total para el cáncer de recto localmente avanzado resecable.DISEÑO:El estudio fue un ensayo prospectivo fase II de brazo único.AMBITO:Estudio realizado en múltiples instituciones.PACIENTES:Se incluyeron 58 pacientes con cáncer de recto localmente avanzado resecable.INTERVENCIÓN:Se administraron tres ciclos de S-1 con oxaliplatino antes de la cirugía. Se administró S-1 por vía oral a 80 mg / m2 / día durante 14 días consecutivos, seguido de un período de descanso de 7 días. El oxaliplatino se administró por vía intravenosa el primer día a una dosis de 130 mg / m2 / día. Se consideró la duración de un ciclo de 21 días. Posterior a la quimioterapia neoadyuvante se realizó la excisión total mesorrectal con disección ganglionar bilateral.PRINCIPALES VARIABLES EVALUDADAS:El estudio fue diseñado para conocer la factibilidad y eficacia de S-1 con oxaliplatino como quimioterapia neoadyuvante.RESULTADOS:La tasa de conclusión con tres ciclos de S-1 con oxaliplatino como quimioterapia neoadyuvante fue del 94,8% (55/58). Los motivos de interrupción fueron trombocitopenia (3,4%) y daño hepático (1,7%). El efecto adverso grave más común (grado ≥ 3) de la quimioterapia neoadyuvante fue la trombocitopenia (3,4%). No hubo síntomas clínicos adversos graves. Como resultado, la resección R0 se logró en 51 de 52 pacientes (98,1%). Una respuesta patológica completa se obtuvo en 10 pacientes (19,2%).LIMITACIONES:Fue un estudio de fase II no aleatorizado de un solo brazo.CONCLUSIONES:La combinación de S-1 con oxaliplatino como quimioterapia neoadyuvante y escisión mesorrectal total es factible y es una opción de tratamiento prometedora para el cáncer de recto localmente avanzado resecable. Consulte Video Resumen en http://links.lww.com/DCR/B555. (Traducción-Dr Juan Antonio Villanueva-Herrero).

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.

Social implementation of a remote surgery system in Japan: a field experiment using a newly developed surgical robot via a commercial network.

PURPOSE: In 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. METHODS: A 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. RESULTS: The 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. CONCLUSIONS: The social implementation of telesurgery using the currently available commercial communication network is feasible.

Robotic surgery contributes to the preservation of bowel and urinary function after total mesorectal excision: comparisons with transanal and conventional laparoscopic surgery.

BACKGROUND: Determine whether robotic surgery is more effective than transanal and conventional laparoscopic surgery in preserving bowel and urinary function after total mesorectal excision (TME). METHODS: Of 79 lower rectal cancer patients who underwent function-preserving TME between 2016 and 2020, 64 patients consented to a prospective questionnaire-based functional observation study (52 responded). At 6 months post-resection or ileostomy closure, Wexner, low anterior resection syndrome (LARS), modified fecal incontinence quality of life, and international prostate symptom scores were used to evaluate bowel and urinary function, comparing robotic surgery (RTME) with transanal (taTME) or conventional laparoscopic surgery (LTME). RESULTS: RTME was performed in 35 patients (54.7%), taTME in 15 (23.4%), and LTME in 14 (21.9%). While preoperative bowel/urinary functions were similar in all three procedures, and the distance from the anal verge to tumor was almost the same, more hand-sewn anastomoses were performed and the anastomotic height from the anal verge was shorter in taTME than RTME. At 2 years post-resection, 8 patients (12.5%) had a permanent stoma; RTME showed a significantly lower rate of permanent stoma than taTME (2.9% vs. 40%, p < 0.01). Despite no significant difference, all bowel function assessments were better in RTME than in taTME or LTME. Major LARS was observed in all taTME and LTME cases, but only 78.8% of RTME. No clear difference arose between RTME and taTME in urinary function; urinary dysfunction was more severe in LTME than RTME (36.4% vs. 6.1%, p = 0.02). CONCLUSIONS: In function-preserving TME for lower rectal cancer, robotic surgery was suggested to be more effective than transanal and conventional laparoscopic surgery in terms of bowel and urinary functions.

[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.

Effective dissection for rectal cancer with lateral lymph node metastasis based on prognostic factors and recurrence type.

PURPOSE: There are no reports showing the significance and effective range of dissection for patients with lateral lymph node metastasis (LLNM). This study aimed to investigate the indications for lateral lymph node dissection (LLND) in patients with LLNM based on prognostic factors and recurrence types. METHODS: We reviewed 379 patients with advanced rectal cancer who were treated with total mesorectal excision plus LLND. We analyzed background factors and survival times of patients who had LLNM to determine prognostic factors and recurrence types. RESULTS: Pathological LLNM occurred in 44 (11.6%). Among patients with LLNM, the predictors of poor prognoses, according to univariate analysis, were > 3 node metastases, the presence of node metastasis on both sides, and spreading beyond the internal iliac lymph nodes. Moreover, LLNM beyond the internal iliac region was found to be an independent prognostic risk factor. Twenty-eight of the 44 patients with lateral lymph node metastasis (64%) relapsed, 22 of whom had distant metastases and 11 of whom experienced local recurrences. Among the latter group, nine (20%) and two (5%) had recurrences in the central and lateral pelvis, respectively. CONCLUSION: The therapeutic benefit of resection was high, especially in patients with ≤ 3 positive lateral lymph nodes, one-sided bilateral lymph node areas, and positive nodes localized near the internal iliac artery.

Widespread anorectal lymphovascular networks and tissue drainage: analyses from submucosal India ink injection and indocyanine green fluorescence imaging.

AIM: Abdominoperineal resection is associated with poor prognosis in patients with advanced lower rectal cancer. This study aimed to analyse the functional lymphovascular network and tissue drainage in the anorectal region. METHODS: In this descriptive study, we performed microanatomical evaluations and intra-operative imaging analysis in a cadaver and patients with rectal cancer. Specimens with India ink injection were collected from a cadaver and from six patients who underwent abdominoperineal resection. Intra-operative indocyanine green fluorescence imaging was performed on four patients who underwent surgery for lower rectal cancer. India ink was injected into the submucosa at the dentate line of specimens. Tissue sections were examined by immunohistochemistry for D2-40 and CD31. Intra-operative indocyanine green was injected into the submucosa at the dentate line. Lymph flow was traced using a near-infrared camera system. RESULTS: Fascia branching from the rectal longitudinal muscle layer extended to the posterior hiatal ligament and lateral endopelvic fascia connective tissue lamina on the surface of the levator ani muscle. The fascia contained veins labelled with ink in their lumina and initial lymphatics. Intra-operative indocyanine green fluorescence imaging revealed extensive lymph flow from the muscle layer of the anal canal to the hiatal ligament and endopelvic fascia along the longitudinal muscle layer fibres. CONCLUSIONS: The anorectal region contained widespread venous and lymphatic networks in proportion to its specific connective tissue framework around the longitudinal-muscle-layer-extending muscle bundles, which provides extensive networks for tissue fluid and cells.

Short-term outcomes of robotic-assisted laparoscopic versus laparoscopic lateral lymph node dissection for advanced lower rectal cancer.

BACKGROUND: Therapeutic strategies to suppress local recurrence, including lateral lymph node metastasis, are important to improve the curability of rectal cancer. The aim of the present study was to clarify the advantages of robotic-assisted laparoscopic lateral lymph node dissection (RALLD), comparing its short-term outcomes with those of laparoscopic lateral lymph node dissection (LLLD). There are some retrospective reports comparing RALLD or LLLD and open lateral lymph node dissection (OLLD), but few reports comparing RALLD and LLND to each other. METHODS: From November 2014 to August 2020, we compared the short-term outcomes in 40 patients who underwent RALLD and 55 patients who underwent LLLD. RESULTS: The total operative time was significantly longer in the RALLD group than in the LLLD group (p < 0.001). However, lateral dissection time was not significantly different between the groups (p = 0.661). The postoperative hospital time was shorter in the RALLD group than in the LLLD group (p < 0.048). No significant differences were identified in the rates of postoperative bleeding, incisional surgical site infection (SSI), organ/space SSI, urinary disfunction, urinary infection, or small bowel obstruction between the groups. However, anastomotic leakage was significantly lower in the RALLD group than in the LLLD group (p = 0.031). CONCLUSIONS: The short-term outcomes of RALLD indicate it is feasible, and RALLD may be a useful modality for lower rectal cancer.

[Short-Term Results of Robot-Assisted Surgery in Patients Undergoing Neoadjuvant Chemotherapy for Rectal Cancer].

The advantages of robot-assisted surgery include: stable deployment of the robotic arm that enables excellent radical cure characteristics and preservation of function; the ability to perform precise surgery even in patients in whom performing laparoscopic surgery is difficult, such as those with pelvic or bulky tumors. However, there have been some reports on such issues as an increase in the incidence of postoperative complications and an increase in postoperative hospital stay in patients who underwent neoadjuvant chemotherapy(NAC); thus, we summarized and are reporting the short-term results of our experience in patients seen in our department to date. A total of 76 patients with rectal cancer who underwent robot-assisted surgery, and short-term postoperative results were compared between patients who underwent neoadjuvant chemotherapy (NAC group)and those who did not undergo neoadjuvant chemotherapy(non-NAC group). Of the 76 patients, 59 (77.6%)were male and 17(22.4%)were female, and 27(35.5%)in the NAC group. In the comparisons between the NAC and non-NAC groups, although the difference in operative time(523.5 vs 317.5 minutes, p<0.01)was significant, there were no significant differences in any of blood loss(59 vs 20g, p=0.22), postoperative hospital stay(14 vs 13 days: p=0.07), and onset of complications that were Clavien-Dindo Grade Ⅲa or higher(2 vs 1 patients, p=0.82). Robot- assisted surgery after NAC for rectal cancer was considered to be safe and very useful.

[Significance of Neoadjuvant Chemotherapy before Colorectomy and Hepatectomy].

BACKGROUND: We discuss the significance of neoadjuvant chemotherapy for resectable simultaneous liver metastases in our department. SUBJECT: We examined 73 cases of resectable simultaneous colorectal liver metastases surgeries occurred in our department from 2000 to 2019. RESULTS: There were 13 patients in the chemotherapy before colorectomy group(before colorectomy group), 24 patients in the chemotherapy before hepatectomy group(before hepatectomy group), and 36 patients in the no chemotherapy group(no chemo group). Five-year overall survival in Grade A/B was 77.8%/100% in the before colorectomy group, 50.0%/42.4% in the before hepatectomy group and 45.6%/66.2% in the no chemo group. Three-year progression-free survival in Grade A/B was 51.9%/50.0% in the before colorectomy group, 16.7%/40.4% in the before hepatectomy group and 46.5%/55.6% in the no chemo group. Six patients in the before colorectomy group had no local recurrence, lymph node recurrence, or peritoneal dissemination. CONCLUSION: Patients in the before colorectomy group were expected to have prolonged survival. There was no local recurrence, lymph node recurrence, or peritoneal dissemination in the before colorectomy group, suggesting the possibility of controlling them.

[The Validity of a Stent-Independent Strategy for Left-Sided Stenotic Colon Cancer].

In recent years, stenting and stoma creation as a bridge to surgery for obstructive left-sided colon cancer have been attracting attention. Our team has a stent-independent strategy and performs primary resection after stoma construction and preoperative chemotherapy with cT4 patients. In this study, we investigated both its validity and issues. Sixty-five cases of scope-impassable left-sided colon cancer surgeries from November 2015 to September 2020 were included. The short- and long-term results were examined in Stage Ⅱ-Ⅲ and Ⅳ. The median time from admission to surgery was 6 days and 8 days, respectively; postoperative morbidity was 9.5% and 17.4%, respectively; anastomotic leakage was 4.8% and 17.4%, respectively; permanent stoma was 26.2% and 21.7%, respectively; and postoperative death was zero in both groups. In group Ⅱ-Ⅲ, the 3-year overall survival rate was 77.0%, 3-year disease-free survival rate was 72.7%, and in group Ⅳ, the 3-year overall survival rate was 36.0%. Local recurrence was observed in 2(16.7%)of 12 patients with cT3-4N+ rectosigmoid cancer who did not receive neoadjuvant chemotherapy. The stent-independent strategy was safe with low morbidity, and the permanent stoma rate was reasonable.

[Treatment for Laterally Invasive Rectal Cancer with Robot-Assisted Surgery after Preoperative Treatment].

The patient is a 40-year-old male. He was referred to our department because, after a thorough examination, he was diagnosed with rectal cancer. Preoperative imaging showed a tumor in the rectum at the level of the seminal vesicles, and left lateral invasion was suspected. In addition, lymph node metastases in the left lateral area were suspected. We performed a robot-assisted low anterior resection plus bilateral lateral dissection plus covering ileostomy for this patient after neoadjuvant chemotherapy. The operation time was 495 minutes, and the blood loss was 50 g. The histopathological diagnosis was pT3, N3(#263), M0, pStage Ⅲc, PM0, DM0, RM0, R0, Cur A. In Japan, robotic-assisted surgery for rectal cancer has been covered by insurance since April 2018, and in our department, robotic surgery is the first option for any stage or type of surgery for rectal cancer. We believe that the greatest advantages of robotic surgery for rectal cancer are in lateral dissection, ie, the better understanding of how blood vessels and nerves travel around the internal iliac vessels and the associated anatomy of pelvic organs that comes from reliable lateral dissection. We have experienced a case of safe robotic-assisted radical resection of laterally invasive rectal cancer, which is considered to be relatively difficult, and we hereby report the usefulness of the robotic-assisted modality.