勝野 秀稔

BACKGROUND: The da Vinci™ Surgical System, recognized as the leading surgical robotic platform globally, now faces competition from a growing number of new robotic surgical systems. With the expiration of key patents, innovative entrants have emerged, each offering unique features to address limitations and challenges in minimally invasive surgery. The hinotori™ Surgical Robot System (hinotori), developed in Japan and approved for clinical use in November 2022, represents one such entrant. This study demonstrates initial insights into the application of the hinotori in robot-assisted surgeries for patients with rectal neoplasms. METHODS: The present study, conducted at a single institution, retrospectively reviewed 28 patients with rectal neoplasms treated with the hinotori from November 2022 to March 2024. The surgical technique involved placing five ports, including one for an assistant, and performing either total or tumor-specific mesorectal excision using the double bipolar method (DBM). The DBM uses two bipolar instruments depending on the situation, typically Maryland bipolar forceps on the right and Fenestrated bipolar forceps on the left, to allow precise dissection, hemostasis, and lymph node dissection. RESULTS: The study group comprised 28 patients, half of whom were male. The median age was 62 years and the body mass index stood at 22.1 kg/m2. Distribution of clinical stages included eight at stage I, five at stage II, twelve at stage III, and three at stage IV. The majority, 26 patients (92.9%), underwent anterior resection using a double stapling technique. There were no intraoperative complications or conversions to other surgical approaches. The median operative time and cockpit time were 257 and 148 min, respectively. Blood loss was 15 mL. Postoperative complications were infrequent, with only one patient experiencing transient ileus. A median of 18 lymph nodes was retrieved, and no positive surgical margins were identified. CONCLUSIONS: The introduction of the hinotori for rectal neoplasms appears to be safe and feasible, particularly when performed by experienced robotic surgeons. The double bipolar method enabled precise dissection and hemostasis, contributing to minimal blood loss and effective lymph node dissection.

Although meta-analyses and systematic reviews have clarified the benefits of robotic surgery, few studies have focused on robotic rectal surgery (RRS) and the use of Endowrist® instruments. Therefore, we evaluated RRS using the double bipolar method (DBM) and compared its short-term outcomes with those of RRS using the single bipolar method (SBM). This study enrolled 157 consecutive patients and all procedures were performed by the same surgeon and recorded through short video clips. We analyzed the patient demographics and short-term clinical outcomes. Although this observational study has several limitations, the console time for total mesorectal excision using the DBM was significantly shorter than that using the SBM. Although the DBM did not demonstrate a specific learning curve, it was a safe and feasible procedure even for patients with advanced disease. Further studies are needed to evaluate the cost-effectiveness of the DBM.

The number of patients undergoing robotic surgery for rectal cancer has rapidly increased in Japan, since the government approved the procedure for national insurance coverage in April 2018. Robotic surgery has the potential to overcome some limitations of laparoscopic surgery, especially in the narrow pelvis, providing a three-dimensional view, articulated instruments, and a stable camera platform. Although meta-analyses and randomized controlled trials have failed to demonstrate the superiority of robotic surgery over laparoscopic surgery with respect to the short-term clinical outcomes, the published findings suggest that robotic surgery may be potentially beneficial for patients who are obese, male, or patients undergoing sphincter-preserving surgery for rectal cancer. The safety and feasibility of robotic surgery for lateral lymph node dissection, the standard procedure for locally advanced lower rectal cancer in Japan, have been demonstrated in some retrospective studies. However, additional prospective, randomized trials are required to determine the actual benefits of robotic surgery to ameliorate the urogenital and oncological outcomes. The cost of this approach is a long-standing principal concern. A literature search showed that the cost of robotic surgery for rectal cancer was 1.3-2.5 times higher per patient than that for the laparoscopic approach. We herein describe our surgical technique using a da Vinci Surgical System (S/Si/Xi) with 10 years of experience in performing robotic surgery. We also review current evidence regarding short-term clinical and long-term oncological outcomes, lateral lymph node dissection, and the cost of the procedure.

Systemic and local immunological responses were studied in patients with or without preoperative administration of chemotherapeutic and/or immunotherapeutic drugs for colorectal cancer. The plasma TGFbeta and other cytokines such as IL-2, IL-4, IL-6, IL-10, IL-12, IFN-gamma in the supernatant fluid of culture of peripheral blood mononuclear cell (PBMC) and regional lymph node were measured by the ELISA method. A systemic response of cytokines was as follows: the production of plasma TGFbeta increased in many cases by chemotherapeutic drugs with a significant elevation of the mean production. Productions of IFN-gamma, IL-2, IL-12 in the supernatant fluid of culture of PBMC increased in many cases by immunotherapeutic drugs, and that of IL-4, IL-6 increased in many cases by chemotherapeutic drugs. A local response of cytokines was as follows: the production of IL-2 by immunotherapeutic drugs was greater than that without immunotherapeutic drugs whereas the production of IL-10 by immunotherapeutic drugs was smaller than that without immunotherapeutic drugs.

進行大腸癌手術症例を対照群と化学療法群に無作為に分け,対照群では術前の化学療法を施行せず,加療群ではUFTを手術前日迄の14日間経口投与した.術前に化学療法を施行することによって起こる免疫抑制状態の有無を,血漿中と所属リンパ節細胞の培養上清中のTGF-β発現量を指標として検討した.その結果,腫瘍最大径と深達度において血漿TGF-β発現量との関連性が認められ,より進行した癌で免疫抑制状態が引き起こされていることが示唆された.術直前の方が術前14日前に比し血漿TGF-β発現量は対照群及び加療群共に増加傾向にあり,加療群では有意に増加していた.担癌宿主の免疫抑制状態は化学療法を行うことによって,より助長されると考えられた.以上より,術前化学療法は全身及び局所リンパ節における免疫機構を抑制する働きを有する可能性が示唆された