From Scope to Scalpel: A Review of the Timing and Outcomes of Conversion in Minimally Invasive Liver Resections

Minimally invasive liver resection (MILR), encompassing laparoscopic and robotic techniques, has transformed hepatobiliary surgery. Despite its advantages, intraoperative conversion to open surgery remains a critical event, often associated with increased blood loss, morbidity, and longer hospital stay. Timing of conversion - whether early or delayed - emerges as a key determinant of patient outcomes yet remains poorly defined in the literature.

This review synthesizes current evidence on the indications, timing, and outcomes of conversion in MILR, with a focus on identifying risk factors, perioperative consequences, and existing knowledge gaps.

A systematic search of PubMed, MEDLINE, and Embase was performed (2010-2025). We included studies comparing converted vs. non-converted MILR. A quantitative synthesis was performed for key outcomes.

Fifteen studies (15,834 patients) were included. A quantitative analysis revealed that conversion was associated with significantly increased blood loss (mean difference: 450 mL), higher overall morbidity (OR: 2.5), and longer hospital stays (mean difference: 4.2 days). We propose an operational definition: Early Conversion (<60 mins or pre-parenchymal transection), **Late Conversion** (>60 mins or post-parenchymal transection), and Emergency Conversion (life-threatening event). We propose operational definitions for conversion timing (Early, Late, Emergency) and developed a decision-making algorithm.

Conversion during MILR is a pivotal safety measure, but its timing substantially influences outcomes. There is a pressing need for a national, prospective, multicentre UK-based audit to define optimal conversion timing, identify modifiable risk factors, and inform standardised intraoperative decision-making frameworks.