Does the laparoscopic Nissen procedure reduce the reoperation rates for patients with gastro-esophageal reflux disease (GERD) when compared to the robot-assisted Nissen fundoplication? – An Update

Objective: To test whether selection bias has affected the reported effect estimate for the laparoscopic Nissen procedure to reduce the reoperation rates for patients with GERD disease in comparison to robot-assisted Nissen fundoplication (RD 0.11. 95%CI: -0.14 to 0.36). Method: Trial adjusted, simulated comparator trial (SCT) based I2 test for single randomised controlled trials, using revised I2 threshold limits. Result: A baseline covariate imbalance, either due to chance or due to selection bias was established, being equivalent to selection bias level = B% 50-60 (Bias category = 3). This level suggests that 41-60% of (8 – 12 of the total 20) subjects were non-randomly allocated in favour of one treatment group above the other. Conclusion: The effect estimate reported by the tested trial does not suggest any significant differences between both types of procedure in reducing reoperation rates. However, the selection bias level, estimated by use of the trial adjusted, SCT based I2 test for single RCTs (B% = 50-60), appears to be high enough in order to have affected the reported estimate. In line with new findings, this report updates previous report to the same RCT: EBSM Volume 2, Issue 1, 2026 Pages 19-22, DOI: 10.5281/zenodo.17760847.