Guselkumab Vs Ustekinumab in Stricturing Crohn's Disease

Inclusion Criteria: * Confirmed patients with moderate-to-severe Crohn's disease (CD), aged 18 to 80 years, receiving treatment with Guselkumab or Ustekinumab. * Presence of obstructive symptoms consistent with chronic or subacute intestinal obstruction within the past 8 weeks, with confirmed postprandial abdominal pain attributable to strictures, with the exclusion of: ① mild to moderate pain (postprandial abdominal pain or abdominal pain exacerbated by diet, ameliorated with abdominal bowel sounds) without nausea, vomiting or abdominal colic; ② dietary restrictions unrelated to abdominal pain. * Evidence of definite luminal strictures caused by the disease itself confirmed by radiographic imaging or endoscopic examination, i.e., meeting any of the following criteria: 1. Enteric computed tomography (CT): Presence of intestinal strictures on enteric CT, with two of the three following findings at the stricture site compared with the adjacent proximal bowel: ① a \>50% reduction in luminal diameter; ② a \>25% increase in bowel wall thickness; ③ pre-stenotic dilation \>2.5 cm. 2. Endoscopic examination: Intestinal strictures that are impassable to the endoscope. Exclusion Criteria: * Patients with severe disease requiring emergency surgery or endoscopic therapeutic intervention, or those judged by the attending clinician to need a switch of medication or elective surgery within 2 months, such as those with acute severe intestinal obstruction, perforation, intra-abdominal abscess, intra-abdominal adhesion, and other conditions leading to obstruction, hemorrhage, infection, etc. * Intestinal obstruction, intra-abdominal abscess, isolated intestinal stricture and other lesions secondary to surgery. * Patients who have received definitive therapeutic interventions for strictures within the past 6 months, such as endoscopic balloon dilation, stricture incision, intestinal stricture plasty, surgical/manual anal dilatation, etc. * Severe patients who remain unable to take oral intake despite enteral nutrition (EN) administration for more than 2 months. * Patients who have used Guselkumab (GUS), Ustekinumab (UST) or other IL-23 antagonists within the past 12 months; or those with contraindications to GUS/UST, or intolerance to the study medications due to other causes (e.g., allergy to IL-23 antagonists). * Patients with contraindications to small intestinal computed tomography (CT), such as contrast media allergy. * Patients with relative contraindications to biological agents, such as active tuberculosis with a positive chest X-ray for pulmonary tuberculosis or a strongly positive tuberculin skin test; a history of myocardial infarction, heart failure or demyelinating neurological diseases within the past 5 years. * Patients currently suffering from solid tumors, with a past history of lymphoma or melanoma, or undergoing chemotherapy or radiotherapy. * Patients complicated with intestinal dysplasia (e.g., diagnosed with short bowel syndrome), colostomy or colorectal neoplasms. * Patients complicated with active massive gastrointestinal hemorrhage, severe hepatic and renal dysfunction, active bacterial or viral infection, shock, as well as intractable vomiting and severe malabsorption syndrome. * Pregnant or lactating patients. * Patients with severe hemodynamic and vital sign instability, or those with rapidly progressive or end-stage diseases. * Patients with psychiatric disorders, or those with insufficient educational level to fully understand the study content or unable to cooperate with the completion of the study.