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

## TL;DR

A new Veress needle design, VeressPlus, shows significantly safer and more consistent insertion depths for beginners compared to the conventional Veress needle.

## Contribution

The study introduces a novel safety improvement in laparoscopic surgery tools by evaluating a new Veress needle design for reduced learning curve and safer insertion.

## Key findings

- The VeressPlus needle showed no learning curve, unlike the conventional Veress needle which required 8 trials to reach a plateau.
- At the 8th trial, the VeressPlus needle had significantly lower average insertion depth (5.4 mm) compared to the conventional needle (12.7 mm).
- Only 8% of VeressPlus users exceeded the safe insertion depth, compared to 46% for the conventional 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 the 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 that of a conventional VN, under standardized conditions.

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.

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 favor of the VN+ (mean: 5.4 mm SD 1.4) compared to the VN (mean: 12.7 mm SD 6). In the VN group and VN+ group, 46% versus 8% exceeded the safe insertion depth of 10 mm at the end of the learning curve.

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.

The online version contains supplementary material available at 10.1007/s00464-025-12273-4.