In patients with obstructed colorectal cancer (CRC), a self-expandable metallic stent (SEMS) can be placed across the tumor as a bridge-to-surgery (BTS). Following stent decompression of the obstructed bowel, it becomes feasible to assess the proximal colon for synchronous neoplastic lesions. The aim of this study is to examine the role of a preoperative completion colonoscopy in the management of stented patients prior to definitive surgery and to determine whether this affects operative management. From 2004 to 2023, all patients admitted under the Department of Colorectal Surgery in our institution who underwent SEMS for obstructed CRC were retrospectively reviewed from a prospectively collected database. The number of patients who had a preoperative completion colonoscopy was analyzed for the presence of synchronous colonic tumors, benign adenomas, and mucosal ischemia. A total of 140 patients with obstructed CRC underwent SEMS. SEMS was successful in 126 patients. One hundred and two patients had SEMS as a BTS, and a preoperative colonoscopy was attempted in 30 of these patients. Full colonoscopy through the stent was successful in 24 patients without complications. Six preoperative colonoscopies failed due to inadequate stool clearance in the proximal colon or technical difficulties in traversing the colonoscope through the stent or colon. A synchronous tumor was detected in 1 of the 24 successful procedures, located distal to the obstructed sigmoid tumor. Additionally, mucosal ischemia was noted in the proximal colon in 4 of the 24 patients, which required adjustment of the resection margins. One patient underwent a subtotal colectomy instead of a segmental colectomy due to multiple adenomas proximal to the stented tumor. Of the stented patients who did not undergo preoperative colonoscopy, one patient required a defunctioning stoma due to ulceration proximal to the stented tumor seen at the time of surgery, while another was later found to have an obstructing metachronous cancer requiring repeat emergency surgery. Twenty-eight out of 78 stented patients (35.9%) who did not have preoperative colonoscopy never underwent completion colonoscopy even after surgery. Preoperative completion colonoscopy after SEMS placement in patients with obstructed CRC is safe, aids in surgical planning, and prevents missed lesions.
The Japan Society for Endoscopic Surgery (JSES) conducts a nationwide survey every 2 years to evaluate the status and trends of endoscopic surgery in Japan. This article reports the results of the 17th Nationwide Survey conducted by the JSES in 2022 and 2023. A questionnaire assessing the current status of endoscopic surgery was distributed to institutions nationwide. Since 1990, a total of 4 286 446 endoscopic procedures have been performed in Japan, with a continuous increase in most surgical fields. Although the number of procedures temporarily declined during the COVID-19 pandemic, endoscopic surgical activity steadily recovered and increased across all disciplines. Furthermore, the use of robot-assisted surgery has expanded rapidly in multiple specialties, reflecting broader clinical adoption and technological progress. These nationwide data demonstrate that endoscopic surgery is widely and safely performed across all surgical specialties in Japan. The findings of this multidisciplinary survey provide valuable insights into current practice patterns and will contribute to further development, standardization, and safe dissemination of endoscopic surgery.
To examine the risk factors for open conversion during minimally invasive colorectal surgery and to investigate the impact of open conversion on short- and long-term prognosis. Between 2016 and 2023, we retrospectively reviewed 4943 patients who underwent robotic or laparoscopic colorectal surgery. Patients were divided into those who underwent intraoperative open conversion (conversion group, n = 30) and those who underwent surgery without conversion (nonconversion group, n = 4913). Clinical characteristics were compared between the groups. Multivariate analysis revealed surgery performed by an expert surgeon (odds ratio [OR]: 0.361, 95% confidence interval [CI]: 0.158-0.822, p = 0.015) as a negative predictor and combined resection of adjacent structures (OR: 4.264, 95% CI: 1.715-10.604, p = 0.001), and clinical T4 disease (OR: 3.215, 95% CI: 1.415-7.465, p = 0.005) as positive predictors of open conversion. Open conversion was an independent predictor of postoperative complications (OR: 2.550, 95% CI: 1.201-5.414, p = 0.014) and relapse-free survival (hazard ratio [HR]: 3.343, 95% CI: 1.232-8.923, p = 0.030). Open conversions were less frequent when performed by experts and more common in advanced tumor stages. For patients at increased risk of conversion, the procedure should preferably be performed in centers with established techniques and experienced surgeons.
Anatomical segmentectomy of the liver is a standard procedure used in hepatocellular carcinoma (HCC) resections. In laparoscopic hepatectomy, negative staining of the hepatic segments is predominantly used because the direct puncture of the portal branches under the guidance of intraoperative ultrasonography (IOUS) is technically demanding. Alternatively, in robotic hepatectomy, intracorporeal positive staining of the hepatic segments may be feasible. Positive staining of the hepatic segments to be removed (segment 3 in four cases and segment 6 in one case) was performed. The diseases were HCC (n = 3) and colorectal liver metastases (n = 2). The tip of the 22G needle attached to the extension tube was placed in the target portal vein branch under IOUS guidance with Maryland bipolar forceps. After injection of indocyanine green solution, the boundary of the target segment visualized in the Firefly mode was easily marked with monopolar curved scissors. Positive staining for S3 and S6 was successful in four of the five cases. Anatomical segmentectomy and partial resection of the liver were performed in three and two patients, respectively. It was feasible to perform positive staining of the hepatic segments under IOUS in robotic hepatectomy, owing to the multijoint function and stability of the robotic arms.
Vaginal natural orifice transluminal surgery (vNOTES) is a promising tool in gynecology and is being increasingly adopted in minimally invasive surgery. The aim of this study is to assess the feasibility and outcomes of vNOTES for morbidly obese patients for gynecological surgeries. Morbidly obese patients (BMI≥40kg/m2) who underwent vNOTES for gynecological conditions from March 2021 to June 2025 were identified. Data on patient demographics, operative factors, complications and postoperative outcomes were collected and analyzed. A literature review on gynecology vNOTES in morbidly obese patients was also performed. 32 patients were identified. The median BMI was 42.1kg/m2 (range 40.0 - 72kg/m2). Their age ranged from 23 to 77 years old. 50% of them had a previous abdominal or pelvic surgery. 50% were nulliparous. The most common procedure performed was total hysterectomy bilateral salpingoophorectomy (81.3%). One patient underwent pelvic lymph node dissection. The median operative time was 150mins (range 75 - 475mins). The median blood loss was 200mL (range 0 - 1700mL). The median length of stay was 2 days (range 1 - 38 days) and postoperative pain scores were low. One patient developed a postoperative pelvic collection that was treated conservatively. In the literature review comparing 3 other studies, the perioperative and postoperative complication rates and median operation time were generally comparable, although this interpretation is limited by the small sample sizes. vNOTES is a feasible approach in morbidly obese patients for various gynaecological surgeries, demonstrating favourable outcomes.
The global burden of inguinal hernia (IH) has significantly increased. Mesh with self-fixating technology helps provide superior tissue integration, reducing the need for additional fixation compared to conventional mesh. Benefits include shorter operative time, reduced hospital stay, lower recurrence rates, and improved quality of life. However, variability remains in its adoption and application. To address this, a panel of Asian hernia experts convened to develop a consensus and formulate recommendations on self-fixating mesh (SFM) use in IH repair. A panel of 13 hernia experts participated in the consensus discussion and manuscript development. A comprehensive literature review was conducted using PubMed, Embase, and Google Scholar to identify relevant articles and formulate statements. Consensus was assessed using a modified three-step Delphi method, with an acceptance level of > 80%. In phase 1 of consensus development, 11 statements were reviewed, with 9 reaching consensus and 1 facing disagreement. Five additional statements were introduced based on expert input. Phase 2 reviewed all 16 statements, with one failing to reach consensus. In phase 3, an online reassessment of the revised version of the failed statement in the previous round was conducted via Microsoft Forms, leading to consensus on all 16 statements. SFM offers significant advantages over conventional sutured meshes in IH repair. However, further research and multicenter trials are recommended to refine surgical protocols. Based on expert recommendations, SFM may be preferred in IH repair, and structured training can enhance its adoption, improving patient outcomes.
The adoption of robot-assisted surgery (RAS) in Japan has progressed significantly since its initial approval in 2009. RAS gradually expanded into various surgical fields with 35 procedures now covered under Japan's national health insurance. This study provides an inaugural assessment of RAS outcomes for seven digestive procedures introduced in 2018. The Japanese Society for Endoscopic Surgery working group established an RAS registry integrating data from the National Clinical Database and additional RAS-specific records. The analysis focused on three major gastrointestinal fields: the esophagus, stomach, and rectum. In 2019, 530 esophagectomies, 2295 gastrectomies, and 3269 proctectomies were performed. RAS for these procedures was characterized by relatively long operative times, low intraoperative blood loss, and very low conversion rates to open surgery (< 1%). Postoperative morbidity rates Grade IIIa or higher were 23.2% for esophagectomy, 4.9% for gastrectomy, and 9.4% for proctectomy. Length of postoperative hospital stay correlated with morbidity, though readmission (1.3%-3.1%) and postoperative mortality rates (0.3%-0.6%) remained low. The early nationwide implementation of RAS in Japan was marked by a high surgeon qualification rate (98.9%) and meticulous case selection; the DVSS Xi model accounted for 66.3% of robotic platforms used. These findings underscore the need for ongoing surveillance and data-driven evaluation to ensure safe and effective implementation of RAS. Future longitudinal analyses will refine surgical quality, optimize resource allocation, and advance minimally invasive techniques. This study highlights the transformative potential of RAS in Japanese surgical practice and its alignment with global trends.
To evaluate the feasibility, safety, and short-term effectiveness of a society-led, proctor-guided Equivalent Certificate program designed to support the supervised initiation of robot-assisted gynecologic surgery in Japan. A multicenter pilot program was conducted across four academic institutions. Fourteen surgeons without prior da Vinci console experience were enrolled. The training pathway included: (1) manufacturer-provided e-learning, on-site system training, and written assessment; (2) institution-based, proctor-supervised training with mandatory simulator proficiency (≥ 80 points across 10 tasks) and at least five bedside assistant cases; (3) standardized proctor evaluation of technical readiness using a 5-point Likert scale; and (4) post-case assessment following each surgeon's first console case. Upon completion of all requirements, participants received an equivalency-based Certificate of da Vinci System Training issued by Intuitive Surgical. Eleven surgeons completed the full program and performed at least one robotic procedure. No intraoperative complications or proctor takeovers occurred. Proctor evaluations demonstrated satisfactory performance across all assessed skill domains, with mean scores ranging from 3.09 to 4.55 out of 5. Instrument insertion and exchange received the highest ratings (mean 4.55), while third-arm control showed relatively lower scores (mean 3.09), consistent with known early learning challenges. The overall composite score was 3.79, indicating performance approaching a "well done" level under supervised conditions. This feasibility study suggests that a structured, society-led Equivalent Certificate program is a feasible and safe approach for the supervised introduction of robot-assisted gynecologic surgery. By integrating manufacturer-aligned education with institution-based proctor supervision and objective performance benchmarks, this framework may serve as a complementary training pathway as robotic surgery education continues to evolve in Japan.
Open radical cystectomy is the current standard treatment for bladder cancer. However, it is associated with high morbidity and mortality, particularly in the elderly. Recently, robotic surgery has become a minimally invasive approach. To this end, we aimed to evaluate the safety and complications of robot-assisted radical cystectomy (RARC) in elderly patients with urothelial carcinoma. We performed a retrospective single-center analysis of 103 patients who underwent RARC between May 2018 and May 2024. The patients were divided into an elderly group (age, ≥ 80 years; n = 24) and a younger group (n = 79). The American Society of Anesthesiologists Physical Status Classification System scores were significantly lower in the elderly group than in the younger group. No significant differences were observed between the two groups in terms of demography. Operative time was shorter in the elderly group than in the younger group. Conversely, the postoperative hospital stay was shorter in the younger group than in the elderly group. There were no significant differences in the frequency or severity of complications between the two groups; however, the incidence of ileus was significantly higher in the elderly group. In addition, higher age, ileus, and days to drain removal were identified as independent factors that prolonged hospitalization. RARC is a safe treatment option for elderly patients with bladder cancer, with complication profiles comparable to those in younger patients. However, the increased risk of ileus and prolonged hospitalization in elderly patients highlights the need for cautious perioperative management to optimize outcomes in this growing population.
Despite its advantages over open and laparoscopic approaches, robotic liver parenchymal transection is difficult because of the lack of a standardized method. Saline-linked cautery (SLiC) method during robotic liver parenchymal transection was previously reported. To verify the safety and practicality of the SLiC method, the perioperative outcomes of laparoscopic liver resection (LLR) and robotic liver resection (RLR) were compared using propensity score matching (PSM). LLRs and RLRs at our institution were analyzed from 2017 to 2024. Liver parenchymal transection of LLRs was performed using laparoscopic coagulating shears or cavitron ultrasonic surgical aspirator, and that of RLRs was performed using the SLiC method. Patient characteristics, surgical factors, and tumor factors were adjusted using PSM. Perioperative outcomes were compared between the LLR and RLR groups. LLR was performed in 145 patients and RLR in 129. Before PSM, tumor size was significantly larger in LLRs than in RLRs, whereas the rate of repeat hepatectomy was significantly higher. Blood loss was significantly lower in RLRs. After PSM, 94 cases were matched and analyzed. RLR substantially reduced intraoperative blood loss (63 mL in LLR vs. 15 mL in RLR, p < 0.01). Multivariate analysis for a higher amount of blood loss showed that the RLR was an independent risk-reducing factor. Comparable perioperative outcomes were observed between RLRs and LLRs, indicating that RLR can be performed safely and practically. The SLiC method is one of the preferred techniques for safer RLR with less blood loss.
Anti-N-Methyl-D-Aspartate receptor encephalitis typically presents with neuropsychiatric symptoms, followed by autonomic dysregulation sometimes necessitating Intensive Care admission. It has a 15% mortality rate and when associated with ovarian teratoma, early surgical excision improves recovery rate by 25%. We describe the first two cases of vaginal Natural Orifice Transluminal Endoscopic Surgery (vNOTES) assisted vaginal adnexectomy for surgical treatment of ovarian teratoma associated anti-NMDA encephalitis and highlight the advantages of this novel approach. These include low insufflation pressures, shorter duration of surgery, avoidance of abdominal scarring, lower pain scores and more rapid recovery. While the outcomes in these two cases suggest that ovarian teratoma associated anti-NMDA encephalitis could be surgically managed through the vNOTES route rather than conventional laparoscopy, more randomized data still need to be available before this becomes standard approach.
Laparoscopic liver resection (LLR) offers advantages such as reduced blood loss and enhanced visualization. However, cases involving tumors compressing the inferior vena cava (IVC) or the root of the hepatic veins remain technically challenging. We present two cases of LLR for tumors compressing IVC and the root of hepatic veins. We developed a new surgical strategy termed the "step-by-step approach", which alternates between liver mobilization and parenchymal transection to safely detach the liver from major vessels. The procedure prevents critical bleeding from major vessels by maintaining liver mobility and ensuring sufficient working space. Case 1 was a 68-year-old man with a 6.5 cm hepatocellular carcinoma (HCC) in Spiegel's lobe compressing IVC and left hepatic vein. Laparoscopic partial hepatectomy of segment 1 was performed. Case 2 was an 82-year-old man with a 5.2 cm HCC in segment 7 compressing IVC and right hepatic vein (RHV). Laparoscopic posterior sectionectomy and dorsal resection of anterior section with combined resection of RHV were performed. Both cases were successfully resected without critical bleeding, achieving a negative surgical margin. This procedure may expand surgical indications to more advanced cases, offering both feasibility and safety.
Preoperative risk assessment is particularly crucial in elderly patients, who often present with comorbidities and organ dysfunction. We investigated the utility of Dementia Assessment Sheet for Community-based Integrated Care System 21-items (DASC-21) in predicting postoperative pneumonia in elderly patients undergoing esophagectomy for esophageal cancer. We retrospectively analyzed 60 patients aged ≥ 75 years who underwent esophagectomy for esophageal cancer between May 2019 and March 2025 at Wakayama Medical University Hospital. The DASC-21 assessment was conducted for all patients aged 75 years or older who were admitted to our hospital before the esophagectomy. Postoperative pneumonia classified as Clavien-Dindo grade ≥ 2 occurred in 13 patients of all the 60 patients (21.7%). Receiver operating characteristic (ROC) curve analysis using postoperative pneumonia as the event showed that the optimal cutoff value of the DASC-21 score was 26 points. Fourteen elderly patients had DASC-21 high scores and 46 had low scores. Patients with high DASC-21 scores had significantly poorer performance status. The DASC-21 high score group had a higher incidence of postoperative pneumonia than the DASC-21 low score group (50.0% vs. 13.0%; p = 0.003). Furthermore, the DASC-21 high score group tended to have a higher transferring rate to other hospitals than the low score group (42.9% vs. 19.6%; p = 0.078). Older age (≥ 78 years old), poor performance status, comorbidity of diabetes mellitus, and DASC-21 high score were suggested as risk factors for postoperative pneumonia by univariate analysis. The preoperative DASC-21 high score was significantly associated with the occurrence of postoperative pneumonia in elderly patients undergoing esophagectomy for esophageal cancer.
Obstructive sleep apnea (OSA) is prevalent in patients with obesity and is a known risk factor for metabolic bariatric surgery (MBS). This study assessed the association between OSA severity and operative outcomes of laparoscopic sleeve gastrectomy (LSG) in a Japanese cohort. We analyzed 141 patients who underwent LSG, divided into two groups based on their apnea-hypopnea index (AHI): a high-AHI group (AHI ≥ 32 events/h; n = 70) and a low-AHI group (AHI < 32 events/h; n = 71). Perioperative outcomes and gastroesophageal reflux disease (GERD) were compared. Multivariable logistic regression was used to identify independent predictors of early postoperative complications. Patient characteristics differed significantly, with higher BMI and a higher proportion of males in the high-AHI group. CPAP was utilized by 87% of patients in the high-AHI group versus 11% in the low-AHI group. There were no significant differences between groups regarding operative time, blood loss, or GERD improvement. Multivariable analysis showed that while AHI was a statistically significant independent predictor of early complications (OR 1.018, 95% CI 1.002-1.035, p = 0.024), its clinical impact was minimal. CPAP usage showed a trend toward risk reduction (OR 0.362, p = 0.172). Severe OSA does not prohibitively increase perioperative risk when managed with appropriate preoperative CPAP therapy.
Roux-en-Y duodenojejunal bypass with sleeve gastrectomy (RY-DJB-SG) generally yields better operative outcomes regarding weight loss and glycemic control compared with SG. However, the requirement of two anastomoses limits its adoption as a primary metabolic bariatric surgery in Japan. To reduce the complexity of RY-DJB-SG, we introduced loop reconstruction for DJB-SG (L-DJB-SG) with a single anastomosis in 2022. This study aimed to assess the feasibility and short-term operative outcomes of L-DJB-SG and RY-DJB-SG. Electronic medical records of 13 and 26 patients who underwent L-DJB-SG and RY-DJB-SG, respectively, between May 2012 and November 2023 at our institute were retrospectively analyzed. Patients' demographic characteristics and glycemic and operative outcomes were statistically compared between the two groups. No significant differences in demographic data were observed between the groups. L-DJB-SG exhibited a shorter operation time (221 [206-268] vs. 304 [283-332.3] min, p < 0.01) and required fewer staplers (2 [1.5-2] vs. 5 [3-5], p < 0.01) for bypass procedures compared with RY-DJB-SG, whereas other operative outcomes were comparable. No significant differences in weight loss or glycemic parameters were noted 1 year after surgery. L-DJB-SG is a feasible and effective procedure that may serve as an alternative DJB option for Japanese patients with obesity and diabetes mellitus.
Morgagni hernia (MH) is a rare diaphragmatic hernia caused by a parasternal defect. We report a case of MH that was successfully repaired using a laparoscopic transabdominal preperitoneal (L-TAPP) approach combined with a self-gripping mesh. A 76-year-old woman was incidentally diagn4osed with MH during a preoperative evaluation of an unrelated knee surgery. Computed tomography revealed herniation of the greater omentum through a diaphragmatic defect measuring ~5 cm × 5 cm. L-TAPP was performed, in which the hernia contents were reduced and wide peritoneal dissection enabled tension-free mesh placement in the extraperitoneal space using a self-gripping mesh. The postoperative course was uneventful, and the patient was discharged on postoperative Day 5, with no recurrence observed at 10 months of follow-up. The L-TAPP approach allows secure mesh placement without direct contact with the intra-abdominal organs, potentially reducing the risk of recurrence and intraperitoneal complications. L-TAPP combined with a self-gripping mesh may be a useful and minimally invasive treatment option for MH.
Subcutaneous emphysema (SE) after minimally invasive surgery is common, but its clinical significance in robot-assisted gastrectomy remains unclear. We evaluated postoperative SE and explored the effect of a lower-pressure insufflation strategy. We retrospectively reviewed 97 patients who underwent curative-intent robot-assisted gastrectomy for gastric cancer. SE on immediate postoperative abdominal radiographs was classified as negative or positive. Outcomes were compared between SE groups and between a standard-pressure period (10 mmHg) and a lower-pressure period (6-8 mmHg). Operative time was dichotomized using a 480-min cutoff based on ROC analysis for CD grade ≥ II complications. AUCs were compared using the DeLong method. A supplementary analysis included the case number. SE occurred in 37 of 97 patients (38.1%). CD grade ≥ II complications were more frequent in the SE-positive than in the SE-negative group (29.7% vs. 8.3%). In the primary parsimonious multivariable model, SE positivity and prolonged operative time were associated with CD grade ≥ II complications. Adding SE to operative time increased the AUC numerically, but not significantly (DeLong p = 0.52). Compared with the standard-pressure period, the lower-pressure period showed a lower SE incidence, fewer CD grade ≥ II complications, and a shorter operative time. In a supplementary analysis, prolonged operative time remained significant, whereas case number was not, and the association with SE was attenuated. Postoperative SE was common and may represent a marker of intraoperative physiologic or technical stress. A lower-pressure insufflation strategy coincided with lower SE incidence and fewer clinically relevant complications. These findings are hypothesis-generating.
To characterize early learning curves for two gynecologic oncologists and their first assistants using the Hugo robotic-assisted surgery system for hysterectomy in benign uterine disease or FIGO stage IA endometrial cancer. We retrospectively examined the first 43 Hugo hysterectomies performed at our center by two surgeons: Surgeon A (experienced with da Vinci) and Surgeon B (robotics-naïve), assisted by three primary assistants (A, B, and C). We analyzed baseline patient characteristics, perioperative outcomes (operative time, docking time, console time, blood loss, complications, length of stay), and plotted learning curves using operative time trends and CUSUM analysis. Surgeon and assistant group comparisons used t-test or Kruskal-Wallis and chi-square as appropriate, with p < 0.05 considered significant. Complications graded ≥ Clavien-Dindo II were considered notable. Patient demographics were similar between groups. Surgeon A achieved significantly shorter operative times (128.6 ± 23.7 vs. 149.8 ± 19.6 min, p = 0.003) and console times (90.9 ± 20.4 vs. 115.6 ± 18.9 min, p < 0.001) versus Surgeon B. Docking times did not differ significantly. No conversions occurred, and complication rates were low and comparable (4% vs. 11%, p = 0.56). CUSUM analysis revealed that Surgeon A's operative times stabilized by case 5, while Surgeon B required approximately 15 cases to reach comparable proficiency. Assistants demonstrated decreasing docking times, with no significant differences among groups. In early Hugo RAS adoption, prior robotic experience led to a shorter learning curve, but robotics-naïve surgeons achieved proficiency within ~15 cases without compromising safety. Assistants also rapidly mastered docking. These findings support safe and efficient implementation of new robotic platforms with structured training.
Laparoscopic subtotal cholecystectomy (LSTC) serves as a bailout procedure when the critical view of safety cannot be achieved during laparoscopic cholecystectomy (LC) for acute cholecystitis (AC). Previous prediction models rely solely on baseline variables without considering temporal changes. We aimed to develop prediction models incorporating both static clinical factors and dynamic laboratory changes using machine learning (ML). We retrospectively analyzed 104 patients who underwent LC for AC between January 2020 and October 2022. Three models were developed: Model 1 using logistic regression with baseline variables, Model 2 incorporating temporal laboratory changes, and Model 3 employing ML algorithms. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). LSTC was performed in 19 patients (18.3%). In Model 1, severity grade II-III was the strongest predictor with an AUROC of 0.735. Model 2 improved performance to an AUROC of 0.782 by incorporating the ALT change rate. Among seven ML algorithms, elastic net achieved the highest AUROC of 0.821. The ML-based model enabled preoperative identification of patients more likely to require LSTC. The model may support preoperative discussions in settings where operative strategies vary.
To determine optimal port placement for retroperitoneal robot-assisted radical nephroureterectomy (RANU) using the Hugo robot-assisted surgery system (HRS) and to compare perioperative outcomes and arm interference between transperitoneal and retroperitoneal approaches. We retrospectively analyzed 21 patients who underwent RANU for upper tract urothelial carcinoma with HRS at our institution between 2023 and 2025 via a transperitoneal (n = 13) or retroperitoneal (n = 8) approach. For clinical retroperitoneal RANU, four robotic ports were placed 3 cm lateral to the erector spinae and spaced 8 cm medially. We compared patient demographics, perioperative metrics, and the rates of arm interference and system-caused errors from log data. Continuous variables were analyzed using the Mann-Whitney U test, whereas categorical variables were analyzed using the chi-squared test or Fisher's exact test. Total operative, console, and dissection times; blood loss; and transfusion and complication rates were comparable between approaches. One transperitoneal case required conversion to da Vinci because of HRS malfunction. The median number of removed lymph nodes was significantly lower in the retroperitoneal group (p = 0.049). The time from incision to roll-in was shorter in the transperitoneal group (p = 0.015), whereas the time from roll-in to console start favored the retroperitoneal approach (p = 0.045). Arm-interference errors were significantly less common for the retroperitoneal approach (p = 0.011), whereas the frequency of system-caused errors did not differ between the groups. Retroperitoneal HRS-RANU was feasible in our cohort and may reduce arm interference; larger studies are needed to confirm this.