Topographic and Anatomical Landmarks of Key Points in Embryologically Guided Surgery for Locally Advanced Gastric Cancer Using Computer-Assisted 3D Navigation.

Background/Objectives: Gastric cancer remains a leading cause of cancer-related mortality, with over 50% of cases diagnosed at a locally advanced or metastatic stage. High-quality surgical resection within the embryological mesogastric layer is critical for achieving optimal oncological outcomes but is often complicated by anatomical distortion in advanced tumors. This study aimed to develop and validate a system of topographic and anatomical navigation landmarks for embryologically guided laparoscopic gastrectomy, leveraging 3D modeling to enhance precision and safety. Methods: A single-center study was conducted, analyzing 78 patients undergoing emergency laparoscopic gastrectomy for locally advanced gastric cancer. Preoperative 3D models were generated from CT data annotations to map the stomach, tumor, vascular structures, and mesogastric adipose tissue. Thirty biomodels were used to refine dissection techniques. Surgical procedures adhered to embryological principles, with lymphadenectomy guided by predefined landmarks. Histopathological validation assessed resection margins and tumor infiltration in resected specimens. Statistical analysis compared outcomes between patients with and without 3D planning. Results: The 3D models demonstrated 100% concordance with intraoperative vascular anatomy. Radiologically dense adipose tissue, resected as potentially tumor-infiltrated, showed histopathological invasion in 74% of cases. R0 resection was achieved in 74.4% of patients. Operative time decreased from 300 to 250 min after technical optimization, with a 7.7% conversion rate (primarily due to vascular injury or tumor fixation). Postoperative mortality was 5.1%, attributed to comorbidities. Patients with 3D planning had significantly higher lymph node yields (p < 0.00001) and R0 rates (p = 0.045). Conclusions: The integration of embryologically based topographic landmarks and 3D navigation improves the safety and standardization of laparoscopic gastrectomy for locally advanced gastric cancer. This approach enhances oncological radicality, reduces operative time, and mitigates risks in anatomically distorted fields. Further validation in larger cohorts is warranted.