Learning curve estimation and insertion depth in Veress needle insertion using a conventional Veress needle and the VeressPlus™ needle

Abstract

The Veress Needle (VN) is commonly used in establishing pneumoperitoneum in laparoscopic surgery. However, severe vascular and/or visceral complications can occur due to overshoot at insertion of the VN in the abdominal cavity. In order to investigate whether the new VeressPLUS needle (VN+) could improve safety, the learning curve of this needle was compared to the one of a conventional VN, under standardised conditions. Methods In total, 26 residents and med students, without prior Veress needle experience, were recruited and randomly assigned to VN or the VN+ group. A learning curve plateau phase recognition model was developed and used to determine the learning curve of the participants who used either the VN or the VN+ needle on two Thiel embalmed human cadavers. Insertion of the needles was done in a systematic way in the upper abdomen and insertion depth was measured under direct laparoscopic vision. At the end of the Learning curve, the number of participants that reached a safe insertion depth between 5 and 15 mm was compared. Results On average, it took the VN group 8 trials to reach, and establish, the plateau phase of the learning curve. The VN+ group showed no learning curve at all. At the 8th trial, a significant difference (p<0.002) in average insertion depth was found in favour of the VN+ (mean: 5,4mm SD1,4) compared to the VN (mean: 12,7mm SD6). In the VN group and VN+ group, 46% vs 8% exceeded the safe insertion depth of 10 mm at the end of the Learning curve Conclusion This study indicates that for novices, there is no learning curve for the VN+, when compared to VN. Moreover, in all cases, the insertion depths were significantly reduced (with more than 50%) while using the VN+ when compared to the VN.