2．da Vinci Xiによる縦隔鏡手術

Mediastinoscopic and Transabdominal Robotic Esophagectomy Using da Vinci Xi

食道癌に対する食道亜全摘術は標準的な外科治療法として確立しているが，従来の開胸手術は高度な侵襲を伴い，術後合併症の発生率が高いことが課題であった．近年この食道亜全摘術においても低侵襲手術の導入がすすんでおり，本邦の多施設共同無作為化比較試験において胸腔鏡手術は開胸手術に比べて非劣性が示され標準治療となった．しかし，最大の致死的合併症が呼吸器合併症であることにかわりはなく，さらなる低侵襲化と合併症率の低減が望まれていた．このような背景のもと，胸壁にまったく傷がない「究極の低侵襲手術」ともいわれる縦隔鏡下食道亜全摘術（mediastinoscopic esophagectomy）が，現在注目されている．

Mediastinoscopic esophagectomy （ME） for esophageal cancer, first reported by Tangoku et al. in 2004, has evolved into a standardized procedure incorporating radical lymphadenectomy. The surgery is performed using a mediastinoscope from the neck and a laparoscope from the abdomen, creating a connected operative field within the mediastinum. ME avoids thoracotomy and one-lung ventilation, preserving respiratory muscles and significantly reducing postoperative pneumonia, while maintaining pulmonary function and quality of life. Meta-analyses have shown that although recurrent laryngeal nerve palsy is relatively common, ME results in shorter operative time, less blood loss, lower incidence of pneumonia, and a reduced overall complication rate compared to conventional approaches. Its greatest advantage lies in expanding surgical indications to patients who were previously considered inoperable due to thoracic adhesions, poor pulmonary function ［e.g., chronic obstructive pulmonary disease （COPD）］, or prior thoracic surgery. These patients often cannot tolerate radiation either, making ME particularly valuable. As Japan’s population continues to age, the need for ME is expected to grow. Although ME was covered by national insurance in 2018, evidence from Japan remains limited. The 2022 esophageal cancer guidelines refrain from recommending ME due to insufficient data. However, recent retrospective studies using propensity score matching have shown significantly better overall and disease-free survival compared to thoracotomy, and prospective multicenter trials are underway.