Proficiency development during the transition from open to totally laparoscopic liver resection: surgical outcomes from a single hepatobiliary surgeon

Background: Totally laparoscopic liver resection (TLLR) is increasingly adopted for benign and malignant liver diseases; however, achieving operative proficiency remains challenging, especially during the transition from open hepatobiliary surgery to advanced laparoscopy. This study evaluated proficiency development and perioperative outcomes of TLLR performed by a single hepatobiliary surgeon at a tertiary referral center. Methods: A prospective observational cohort study was conducted on 99 consecutive patients who underwent TLLR from January 2019 to May 2025. Patients were divided into two predefined chronological phases for comparative analysis. Demographics, operative parameters, postoperative complications, and short-term surgical and margin outcomes were compared. Cumulative sum (CUSUM) analysis of operative time was used to identify the proficiency threshold. Results: Median operative time decreased from 295 minutes in Group A to 207 minutes in Group B ( P = 0.006), and median blood loss decreased from 300 to 115 mL ( P = 0.006). Blood transfusion was less frequent in Group B (34.7% vs. 6.0%, P = 0.003), and conversion occurred only in Group A (16.3% vs. 0%, P = 0.002). Clinically significant complications (Clavien–Dindo ≥ II) were comparable (12.2% vs. 10.0%, P = 0.102), with a similar length of stay (11 vs. 9 days, P = 0.670). CUSUM analysis identified the 25th case as the proficiency inflection point. Conclusion: Operative proficiency in TLLR was achieved after approximately 25 cases, with clear improvements in operative performance, maintenance of low morbidity, and acceptable short-term surgical and margin outcomes.