To develop a novel difficulty scoring system (NDSS) to predict the surgical difficulty of laparoscopic hepatectomy.

A total of 138 patients with liver tumors performed liver resection (LLR) between March 2017 to June 2022 were selected from Affiliated Hospital of Jiangnan University and Wujin Hospital Affiliated with Jiangsu University.

Patient demographics, laboratory tests, intraoperative variables, pathological characteristics were assessed. We also assessed the Child Pugh score and the DSS-B score.

Patients were divided into training and testing cohort according to their hospital. Patients in training cohort were divided into high and low difficult groups based on operation time, blood loss and conversion. Higher percentage of patients with malignant liver tumor (87.0% vs. 58.1%; P = 0.003) or history of hepatobiliary surgery (24.1% vs. 7.0%; P = 0.043) in high difficult group than in low difficult group. To improve the difficulty scoring system, we incorporated the history of hepatobiliary surgery and nature of the tumor. A novel difficulty scoring system was established. The results showed that the operation time (P < 0.001), blood loss (P < 0.001), ALT (P < 0.001) and AST (P = 0.001) were associated with the novel difficulty score significantly. Compared with DSS-B, the NDSS has a higher area under the receiver operating characteristic (AUROC) (0.838 vs. 0.814). The nomogram was established according to the NDSS. The AUROCs of the nomogram in training and testing cohort were 0.833 and 0.767. The calibration curves for the probability of adverse event showed optimal agreement between the probability as predicted by the nomogram and the actual probability.

We developed a nomogram with the NDSS that can predict the difficulty of LLR. This system could more accurately reflect the difficulty of surgery and help liver surgeons to make the surgical plan and ensure the safety of the operation.

开发一种新的难度评分系统（NDSS）来预测腹腔镜肝切除术的手术难度。

选取2017年3月至2022年6月在江南大学附属医院和江苏大学附属武进医院进行肝切除术（LLR）的138例肝肿瘤患者。

评估了患者人口统计学、实验室检查、术中变量、病理特征。我们还评估了 Child Pugh 评分和 DSS-B 评分。

根据医院将患者分为训练组和测试组。训练队列中的患者根据手术时间、失血量和转化率分为高难度组和低难度组。患有恶性肝肿瘤的患者比例更高（87.0% vs. 58.1%；磷= 0.003) 或肝胆手术史 (24.1% vs. 7.0%;磷= 0.043) 高难度组比低难度组。为了改进难度评分系统，我们结合了肝胆手术史和肿瘤性质。建立了新的难度评分系统。结果表明，手术时间（磷 < 0.001), 失血量 (磷< 0.001), ALT (磷< 0.001) 和 AST (磷= 0.001）与新难度分数显着相关。与 DSS-B 相比，NDSS 具有更高的接收器操作特性 (AUROC) 下面积（0.838 对 0.814）。列线图是根据 NDSS 建立的。训练和测试队列中列线图的 AUROC 分别为 0.833 和 0.767。不良事件概率的校准曲线显示列线图预测的概率与实际概率之间的最佳一致性。

我们使用 NDSS 开发了一个列线图，可以预测 LLR 的难度。该系统可以更准确地反映手术难度，帮助肝外科医生制定手术方案，确保手术安全。