儿童肠套叠是部分肠管及其肠系膜套入相邻肠腔内导致的一种特殊类型肠梗阻，发病机制不详，与肠道异常蠕动、肠道黏膜下淋巴细胞增生、病理性诱发点等因素有关。小肠型肠套叠好发于1岁以下婴幼儿，临床表现以发热、呕吐多见；而回结肠型肠套叠则多见于1岁以上患儿，更易出现腹部包块与腹痛。彩超下肠套叠的核-壁比值（脂核厚度/外层肠壁厚度）是鉴别两者最准确的指标，回结肠型肠套叠比值＞1，小肠型肠套叠比值＜1。不同类型的肠套叠治疗方案有所不同。对于症状持续时间＜24 h、套叠肠段长度≤3.0 cm的小肠型肠套叠，自发复位可能性大，可首选禁食及对症支持治疗。回结肠型肠套叠首选透视下空气灌肠复位或超声监视下水压灌肠复位。当尝试灌肠复位3次仍未成功、彩超下提示继发性肠套叠或持续性小肠型肠套叠、x线透视中出现“阑尾征”或“小肠环气征”、d-二聚体＞1.005 mg/L、乳酸≥3.0 mmol/L、淋巴细胞与CRP比值＜0.121，则应考虑行手术治疗。手术治疗上，原发性回结肠型肠套叠首选腹腔镜下肠套叠复位、回盲部-侧腹膜固定术，持续性小肠型肠套叠可经脐单切口腹腔镜下小肠型肠套叠复位或联合病变肠管切除，继发性肠套叠术中需复位肠套叠、切除病理性诱发点以及切除坏死肠段。

Intussusception is a distinctive form of intestinal obstruction characterized by the telescoping of a segment of bowel and its mesentery into an adjacent distal segment. Although its exact pathogenesis remains unclear, it is frequently associated with abnormal intestinal peristalsis, submucosal lymphoid hyperplasia, and the presence of a pathological lead point. Small bowel intussusception typically presents in infants under 1 year of age, with fever and vomiting being common. In contrast, ileocolic intussusception occurs more frequently in children over 1 year old and is often associated with an abdominal mass and pain. The nuclear-to-wall ratio (lipid core thickness/outer bowel wall thickness) is the most accurate differentiator: a ratio ＞1 indicates ileocolic intussusception, while a ratio ＜1 suggests small bowel intussusception. Treatment strategies vary depending on the type and clinical context. For small bowel intussusception with a symptom duration under 24 hours and an intussuscepted segment length ≤3.0 cm, spontaneous reduction is likely, and initial management with fasting and supportive care is recommended. For ileocolic intussusception, fluoroscopy-guided pneumatic reduction or ultrasound-guided hydrostatic reduction is the first-line treatment. Surgical intervention is indicated upon failure of enema reduction after three attempts, or if there is ultrasonographic evidence of secondary/persistent intussusception, or specific imaging findings (e.g., "appendiceal sign" or "air encircling the intussusceptum") during air enema reduction, or abnormal laboratory values (D-dimer ＞1.005 mg/L, lactate ≥3.0 mmol/L, or lymphocyte-to-CRP ratio＜0.121). The surgical approach is tailored to the underlying etiology. For primary ileocolic intussusception, laparoscopic reduction with ileocecal-lateral peritoneal fixation is optimal. In cases of persistent small bowel intussusception, transumbilical single-incision laparoscopic reduction, with or without resection, may be performed. For secondary intussusception, surgical management must include reduction, excision of the pathological lead point, and resection of any necrotic bowels.