# Preoperative evaluation to determine the difficulty of No. 6 lymphadenectomy in laparoscopic gastrectomy

## TL;DR

This study shows that predicting the difficulty of a specific lymph node dissection in stomach surgery can help trainees perform better.

## Contribution

A preoperative method to predict the difficulty of No. 6 lymph node dissection in laparoscopic gastrectomy is proposed and validated.

## Key findings

- Difficulty in No. 6 lymph node dissection was identified in 36.8% of patients based on anatomical characteristics.
- A specific anatomical parameter on CT scans was significantly correlated with intraoperative difficulty.
- Surgical outcomes were not significantly worse when trainees used preoperative predictions compared to specialists without it.

## Abstract

Laparoscopic gastrectomy (LG) requires a long learning curve because of the complicated surgical procedures. Infrapyloric (No. 6) lymph node dissection (LND) is one of the difficult procedures in LG, especially for trainees. This study investigated the impact of the prediction of the difficulty of No. 6 LND.

We retrospectively reviewed the preoperative computed tomography (CT) images and individual operative video records of 57 patients who underwent LG with No. 6 LND to define and predict the No. 6 LND difficulty. To evaluate whether prediction of the difficulty of No. 6 LND could improve surgical outcomes, 48 patients who underwent laparoscopic distal gastrectomy were assessed (30 patients without prediction by a qualified surgeon and 18 patients with prediction by a trainee).

The anatomical characteristic that LND required > 2 cm of dissection along the right gastroepiploic vein was defined as difficulty of No. 6 LND. Of the 57 LG patients, difficulty was identified intraoperatively in 21 patients (36.8%). Among the several evaluated anatomical parameters, the length between the right gastroepiploic vein and the right gastroepiploic artery in the maximum intensity projection in contrast-enhanced CT images was significantly correlated with the intraoperative difficulty of No. 6 LND (p < 0.0001). Surgical outcomes, namely intraoperative minor bleeding, postoperative pancreatic fistula, and drain amylase concentration were not significantly different between LG performed by a trainee with prediction compared with that by a specialist without prediction.

Preoperative evaluation of the difficulty of No. 6 LND is useful for trainees, to improve surgical outcomes.