How do we start intracorporeal anastomosis of colectomy in practice? A real-world, nationwide analysis

The frequency of application of intracorporeal anastomosis (IA) in colon surgery has increased. Although IA usually requires greater surgical skill than extracorporeal anastomosis, no study has elucidated the safe introduction of IA into clinical practice. Overall, 617 patients from 30 hospitals who underwent IA during colon surgery were retrospectively enrolled from the ICAN study group. Each case was assigned to one of four phases according to its position in the number of cases encountered at each hospital: phase 1, from the 1st to the 10th case; phase 2, from the 11th to the 30th; phase 3, from the 31st to the 50th; and phase 4, 51st case and onwards. The length of the distal resection margin in the resected specimens increased in ascending order in phases 1, 2, 3, and 4, respectively (p = 0.008). The frequency of overlap anastomosis increased from 43.4 % in phase 1–89.7 % in phase 4, and that of functional end-to-end anastomosis plummeted from 29.2 % in phase 1 to 0.4 % in phase 4 (p < 0.001). Manual suturing to close the entry hole of the stapler was performed in 28.3 % of cases in phase 1, rising to 78.7 % in phase 4 (p < 0.001). The incidence of anastomosis-related complications was less than 2 % throughout all phases, without statistically significant differences among the phases (p = 0.948). We clearly demonstrated the various efforts expended in clinical practice, especially in terms of case selection and details about the choice of procedures, during the safe introduction of IA at each hospital.