Postoperative complications (Clavien Grade) by simultaneous vs staged operative approaches in 1,004 patients with synchronous colorectal and hepatic metastasis. There was no difference between the groups (all p > 0.05). Clavien Grade ≥ IIIa indicates severe complication. Complications after major and minor resections refer to overall complications. CRLM, colorectal liver metastasis. Postoperative complications: blue bar, overall complications; red bar, severe complications; green bar, after minor resection; tan bar, after major resection.