Safe Trocar Placement by Transvaginal Endoscopic Insertion in Robot-Assisted Surgery for Endometrial Cancer With Umbilical Incisional Hernia and Prior Mesh Repair: Two Case Reports.

We report two cases of endometrial cancer with umbilical incisional hernia or prior mesh repair, in which robot‐assisted surgery was safely performed using transvaginal laparoscope insertion. Both patients had prior abdominal surgeries, and preoperative imaging raised concerns about adhesions or mesh near the umbilicus, making conventional trocar insertion risky. A laparoscope was inserted via the posterior vaginal fornix, allowing real‐time intra‐abdominal visualization and safe port placement under direct vision. In one case, mesh and adhesions were confirmed at the umbilicus. In the other, no adhesions were found within the hernia sac despite being suspected preoperatively, whereas dense adhesions were identified at Palmer's point, which could not be fully characterized by imaging alone. These cases highlight the limitations of relying solely on imaging and underscore the utility of intraoperative visual assessment. Transvaginal scope insertion offers a simple, reproducible method to enhance trocar safety. To our knowledge, no previous reports have described this technique used solely for observation in robot‐assisted surgery for endometrial cancer.

endometrial cancer, incisional hernia, robot‐assisted surgery, surgical mesh, transvaginal endoscopy 1. Introduction Incisional hernias occur in 10%–20% of patients after laparotomy and 5%–10% after laparoscopic procedures, with the umbilicus being the most common site [1, 2]. Mesh repair is generally preferred due to its lower recurrence rate compared to suture closure [3, 4, 5]. The incidence of endometrial cancer is rising due to social and lifestyle changes, with many patients having obesity or prior abdominal surgery—both risk factors for incisional hernia or mesh repair. Robot‐assisted minimally invasive surgery is now a standard approach for endometrial cancer. However, in patients with prior mesh placement or suspected bowel adhesions, conventional trocar insertion may pose risks. Although preoperative imaging, such as CT or MRI, can suggest the location of mesh or adhesions, their accuracy is often insufficient for determining safe trocar placement. To address this issue, we adopted a technique in which a laparoscope is inserted transvaginally prior to robotic trocar placement, solely for initial intra‐abdominal observation. This approach allowed real‐time confirmation of adhesion sites or mesh placement and enabled safe robotic port positioning without requiring specialized equipment or advanced techniques. Importantly, this method differs from vaginal natural orifice transluminal endoscopic surgery (vNOTES) in that it is used only for observation, not for therapeutic intervention. To our knowledge, no previous report has described this technique solely for intra‐abdominal observation in robot‐assisted surgery for endometrial cancer. The aim of this report is to present the feasibility and safety of this transvaginal endoscopic technique as a simple, adjunctive step for safe robotic trocar placement, particularly in patients with a history of abdominal surgery or uncertain adhesion status. 2. Case 1 A 57‐year‐old woman (G4P2, BMI 32.9) had a history of laparoscopic cholecystectomy followed by umbilical incisional hernia repair using a circular mesh (8 cm diameter). She was diagnosed with endometrial cancer (endometrioid adenocarcinoma, Grade 1), with a preoperative clinical suspicion of stage IA disease, and was referred for robot‐assisted surgery. Preoperative CT suggested mesh located just below the umbilicus, but its extent and adhesion status remained unclear. MRI revealed no adhesions in the posterior cul‐de‐sac, and pelvic examination showed good uterine mobility. Prophylactic intravenous antibiotics (cefazolin 1 g) were administered at the induction of anesthesia. This is part of our routine perioperative antibiotic protocol for most surgeries in our department, with additional dosing typically provided 3 h after the start of the procedure. The patient was placed in the lithotomy position. The abdominal skin was prepared with povidone‐iodine, and the vagina was adequately disinfected. The posterior vaginal fornix was exposed using a Sakurai‐type vaginal speculum. After grasping the cervix with a single‐tooth tenaculum and incising the posterior vaginal fornix with Cooper scissors, a 5‐mm trocar (XCEL trocar, Ethicon Inc., Cincinnati, OH, USA; model B5LT) was inserted under direct visualization (Figure 1). Ultrasound guidance was not used during trocar insertion. Care was taken to avoid excessive extension of the incision to prevent gas leakage. After gas insufflation was initiated, a 5‐mm flexible laparoscope (ENDOEYE FLEX, Olympus Corporation, Tokyo, Japan; model LTF‐S190‐5) was then introduced through the trocar to examine the pelvic cavity. Laparoscopic visualization confirmed mesh and bowel adhesions at the umbilicus (Figure 2). After confirming safety, the patient was transitioned to the Trendelenburg position (approximately 25°) to facilitate further intra‐abdominal observation and port placement. Partial adhesiolysis was performed via a left lower quadrant assistant port (AIRSEAL port, CONMED Corporation, Utica, NY, USA; model IAS12‐100LPi), and robotic ports were placed under direct vision (Figure 3). Due to the presence of the mesh, standard periumbilical port placement was not feasible; however, direct visualization allowed trocar placement with minimized deviation from the standard umbilical port positioning while preventing mesh injury. The da Vinci Xi Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA) was used to perform total hysterectomy and bilateral salpingo‐oophorectomy. Despite the more cranially placed ports due to the mesh, surgical manipulation was not impaired (Figure S1). The postoperative course was uneventful. 3. Case 2 A 59‐year‐old woman (G1P1, BMI 22.0) with a history of laparoscopic transverse colon resection and robot‐assisted partial hepatectomy had a large umbilical hernia that had been conservatively managed with compression banding. She was diagnosed with endometrial cancer (endometrioid adenocarcinoma, Grade 1), with a preoperative clinical suspicion of stage IA disease. In these previous surgeries, multiple peritoneal access sites included the left upper abdomen; therefore, adhesions in this area were considered possible. However, preoperative CT mainly suggested bowel adhesions within the hernia sac (Figure S2), while the exact extent and severity of adhesions elsewhere remained unclear. Using the same transvaginal laparoscopic approach, no adhesions were identified within the hernia sac, whereas dense adhesions were visualized at Palmer's point and along the cranial edge of the hernia orifice (Figure 4). Based on this intra‐abdominal assessment, standard robotic port placement could be maintained safely without modification, and the procedure was completed without complication. This approach ensured safe robot‐assisted surgery without bowel injury or conversion, facilitating rapid recovery and contributing to early initiation of chemotherapy for recurrent colorectal cancer. 4. Discussion Incisional hernias frequently occur after abdominal surgery, especially at the umbilicus [1, 2]. The rising prevalence of endometrial cancer, partly due to social and lifestyle changes, has resulted in more patients undergoing robot‐assisted surgery with a background of prior abdominal procedures or mesh repairs. In such cases, conventional trocar insertion can be hazardous, particularly when mesh or adhesions are suspected. Preoperative CT or MRI can show general mesh or adhesion locations, but often lack the resolution to guide safe trocar placement. Previous literature has suggested that transabdominal ultrasonography can be a simple and useful method to identify mesh location and enable safe trocar placement while avoiding injury [6], although real‐time intra‐abdominal visualization may offer superior safety. In cases like the present, where adhesions or mesh placement are suspected due to prior abdominal surgery, intraoperative evaluation is particularly beneficial. In Case 1, this approach allowed precise visualization of mesh and bowel adhesions at the umbilicus, enabling safe trocar placement in close proximity to the mesh while minimizing deviation from the standard port configuration and preventing mesh injury. In Case 2, although adhesions in the left upper abdomen were considered possible based on prior surgeries, preoperative CT mainly suggested adhesions within the hernia sac. However, intraoperative visualization confirmed the absence of adhesions in the sac and instead identified dense adhesions at Palmer's point, which could not be fully characterized by imaging alone. Furthermore, this technique may be particularly useful in cases where detailed information about prior abdominal surgery is unavailable and adhesion risk cannot be accurately predicted. Previous studies have suggested alternative port‐entry strategies, such as lateral abdominal access in patients with prior abdominal surgery [7]; however, even such recommendations may not reliably reflect patient‐specific anatomy without intraoperative confirmation. In both cases, transvaginal laparoscope insertion enabled real‐time visualization and safe port selection. These findings highlight the limitations of relying exclusively on preoperative imaging and support the value of direct endoscopic assessment in enhancing surgical planning and trocar safety. Accordingly, transvaginal observation may be recognized as an additional and useful option to minimize complications associated with trocar placement at prior surgical sites. To minimize resistance during insertion, a 5‐mm trocar and laparoscope are recommended. The thicker handle of the XCEL trocar provides better stability during insertion; however, as the trocar is advanced deeper, the handle may reduce the available vaginal space, requiring careful attention to maintain a proper trajectory. In Case 1, despite these precautions, the transvaginal trocar deviated laterally, likely due to insufficient preoperative assessment of vaginal distensibility and uterine orientation, which resulted in an improper insertion angle. This lateral deviation was confirmed at the start of console operation (Figure S3). Although no complications occurred, this highlights a point of reflection regarding technique. Careful preoperative assessment of uterine mobility and pelvic capacity is vital to ensure adequate access and avoid injury to adjacent structures such as ureters or vessels. Among transvaginal approaches, vNOTES has been increasingly adopted; however, it requires a dedicated access platform and specialized technical skills. In contrast, our technique can be performed with standard instruments and does not require specialized training. It involves only a single trocar insertion for observation, without manipulation or resection. Furthermore, it can be seamlessly integrated into the existing robotic workflow without prolonging operative time. This allows facilities without established vNOTES capability to perform minimally invasive surgery in anatomically challenging patients. Moreover, in endometrial cancer, this method preserves the ability to perform pelvic lymphadenectomy using the standard robotic technique, a step that can be technically challenging with vNOTES. Therefore, when oncologic safety is properly maintained, this approach may also be a valuable option for malignant disease. Previous studies have explored transvaginal access in gynecologic surgery [8, 9], but to our knowledge, this approach has not been previously described specifically as an observation‐only technique prior to robotic surgery for endometrial cancer. The technique we describe is uniquely devoted solely to real‐time intra‐abdominal observation rather than operative intervention, making it simple, reproducible, and widely applicable. Given these potential advantages, oncologic safety must be carefully considered when applying this technique in malignant disease. Oncologic safety is a crucial consideration when introducing transvaginal instrumentation in malignancy. In our cases, the approach was limited to early‐stage endometrial cancer, and the use of povidone‐iodine disinfection, standard antibiotic prophylaxis, and gentle, non‐manipulative access preserved oncologic principles. No cervical ligation was performed, as the access was confined to the posterior vaginal fornix and limited in duration, minimizing the risk of tumor cell dissemination. Institutions that routinely ligate the cervix for endometrial cancer surgery may continue to do so based on their protocols, but our experience suggests it may not be necessary in this specific context. Careful case selection is essential when adopting this approach. Suitable candidates include patients with adequate vaginal distensibility and a mobile uterus without significant adhesions, particularly in the pouch of Douglas. Conversely, this technique should not be used when vaginal malignancy or peritoneal dissemination in the cul‐de‐sac is suspected. In Japan, minimally invasive surgery itself is not indicated for endometrial cancer with suspected dissemination, making such cases inappropriate for this method. Severe pelvic adhesions—particularly those caused by deep endometriosis or an obliterated cul‐de‐sac—should also be considered contraindications, as limited vaginal mobility and restricted access increase the risk of trocar misdirection and inadvertent injury to adjacent structures. Although vaginal stenosis or pelvic organ prolapse may increase the technical difficulty of insertion, they do not necessarily preclude the use of this technique, provided the surgeon has sufficient experience with standard transvaginal procedures. Ultimately, thorough preoperative evaluation including physical examination and imaging is crucial to ensure appropriate candidate selection and procedural safety. This report is limited by its small sample size and single‐institution design, and long‐term oncologic outcomes remain to be determined. Nevertheless, the successful results suggest that this technique may enhance trocar safety in anatomically complex cases. Whether this technique should be regarded as a transitional strategy until imaging modalities improve, or a lasting supplementary method, remains open to evaluation. Advances in CT or MRI may eventually enhance adhesion prediction; however, achieving the real‐time precision provided by direct endoscopic visualization may still be challenging. 5. Conclusion Transvaginal laparoscope insertion enabled safe and effective trocar placement in two patients with endometrial cancer complicated by incisional hernia or prior mesh repair. By providing real‐time intra‐abdominal assessment before trocar insertion, this simple and reproducible adjunctive technique may help overcome the inherent limitations of preoperative imaging and enhance safety in robot‐assisted gynecologic surgery. Further evaluation is warranted to define its role in broader clinical practice. Author Contributions All authors are in agreement with the content of the manuscript. Each author made substantial contributions to the conception, design, drafting, and final approval of the version to be submitted. Consent Informed consent was obtained from both patients for publication. Conflicts of Interest Dr. Tsukasa Baba is an Editorial Board member of ASES Journal and a co‐author of this article. To minimize bias, he was excluded from all editorial decision‐making related to the acceptance of this article for publication. Supporting information Data Availability Statement The data that support the findings of this study are available from the corresponding author upon reasonable request.

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