Robotic-assisted radical colorectal cancer surgery with the KangDuo surgical robotic system vs. the da Vinci Xi surgical system in elderly patients: A multicenter randomized controlled trial - Hao Zhang; Yuliuming Wang; Chunlin Wang; Yunxiao Liu; Xin Wang; Xin Zhang; Yihaoran Yang; Junyang Lu; Lai Xu; Zhen Sun; Zhengqiang Wei; Yi Xiao; et al. (Chinese Medical Journal)