Exploring the potential utility of modified difficulty scores based on the IWATE criteria for assessing the surgical difficulty of laparoscopic repeat liver resection

Laparoscopic repeat liver resection (LRLR) is more challenging than initial laparoscopic liver resection in some cases because of intra-abdominal adhesions and liver deformation caused by previous operations. However, there are insufficient reports on difficulty scoring systems for LRLR. In this study, we aimed to explore whether the IWATE criteria and its modified scoring system could effectively predict surgical outcomes in patients undergoing LRLR.

Patients who underwent LRLR at the Kobe University Hospital between 2014 and 2024 were enrolled. We assessed the correlation between difficulty scores based on the IWATE criteria and LRLR surgical outcomes. The correlation between the modified difficulty scores and LRLR surgical outcomes were also evaluated. The modified difficulty scores were calculated by adding 2 points for ipsilateral recurrence and 1 point for a previous history of open liver resection to the original difficulty scores of the IWATE criteria.

Eighty-four patients who underwent LRLR were enrolled. The median value of the IWATE criteria and modified difficulty score was 4 and 6, respectively. The median operation time and blood loss were 287 min and 10 mL, respectively. Nineteen (23%) patients experienced postoperative complications, wherein four (5%) had Clavien-Dindo grade ≥ IIIa complications. The IWATE criteria difficulty score correlated with operation time (r = 0.52, 95% confidential interval CI 0.35-0.66, P < 0.001) and blood loss (r = 0.26, 95% CI 0.05-0.45, P = 0.018), while the modified difficulty score correlated with operation time (r = 0.53, 95% CI 0.36-0.67, P < 0.001), blood loss (r = 0.31, 95% CI 0.11-0.49, P = 0.004), and overall postoperative complications (odds ratio 1.34 [interquartile range 1.23, 1.47], P = 0.019).

The IWATE criteria and modified difficulty score may be useful for assessing LRLR surgical difficulty. Additionally, the modified difficulty score may more precisely predict the risk of postoperative complications.