Indocyanine green NIR imaging is valuable for lymph node dissection in D3 radical surgery for rectal cancer. It can guide the intraoperative improvement of lymph node dissection based on the preservation of LCA and peripheral autonomic nerves of IMA. This not only reduces the occurrence of postoperative complications and promotes rapid postoperative recovery, but also provides a more precise and individualized comprehensive treatment plan for patients after surgery. In addition，this trial also demonstrated that ICG is safe and feasible for use in rectal cancer

The pathological data of 96 patients with rectal cancer from September 2020 - July 2022 were collected from the First Hospital of Qinhuangdao City.In 51 of these patients, ICG was injected preoperatively via anoscope or anal dilator in the mucosal layer around the tumor, and surgical treatment was performed after visualization. The surgical approach was performed by laparoscopic radical rectal cancer with an intermediate approach step.The IMA root is treated with low ligation of the IMA, while lymph node dissection is performed while preserving the autonomic nerves around the IMA. The other 45 patients were not injected with ICG, and the procedure was performed as before.The occurrence of postoperative complications was recorded, and the detection of lymph nodes was also compared between the two groups, as well as the intraoperative situation and postoperative recovery.

Inclusion Criteria:

1. The preoperative colonoscopic pathological diagnosis was clearly rectal cancer and no malignant tumor in other sites.
2. Good preoperative general condition, no serious cardiopulmonary, hepatic, renal or other major comorbidities before surgery
3. Radical rectal cancer surgery with preservation of LCA and peripheral autonomic nerves of IMA in patients
4. No contraindications to surgery
5. No history of ICG or iodide allergy

Exclusion Criteria:

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