The risk of conversion in minimally invasive oncological abdominal surgery. Meta-analysis of randomized evidence comparing traditional laparoscopic versus robot-assisted techniques

Purpose The objective of this study was to investigate the risk of conversion associated with conventional laparoscopic surgery (LAP) versus robot-assisted surgery (ROB) in patients undergoing abdominal oncological surgery. Possible differences between ROB and LAP on postoperative overall and major morbidity, operative time, and length of hospitalization were also assessed. Methods We included randomized controlled trials of LAP versus ROB surgery in patients with abdominal malignancy. We searched PubMed, EMBASE, and the Central registries through September 2020. Risk of bias was estimated concerning randomization, allocation sequence concealment, blinding, incomplete outcome data, selective outcome reporting, and other biases. Results A total of 1867 patients from 12 trials were included in this review. The rate of conversion was significantly higher for LAP than for ROB patients (10 trials, 1447 participants, p = 0.03, OR = 0.56 [0.33, 0.95]). There was a nonsignificant advantage of ROB over LAP on the rate of overall postoperative morbidity (12 trials, 1867 participants, p = 0.32, OR = 0.83) and major morbidity (7 trials, 792 participants, p = 0.87, OR= 0.93). ROB was also associated with prolonged operative time and abbreviated postoperative hospitalization as compared to LAP (p = 0.002, MD = 27.87, and p = 0.04, MD = -0.57, respectively). Conclusions According to the available highest level of evidence, the application of ROB decreases the incidence of unplanned conversion into an open procedure as compared to standard LAP in the setting of oncological minimally invasive surgery.