Inclusion Criteria:

1. Aged between 18 and 75 years old (18 ≤ age ≤ 75);
2. Diagnosed with primary perianal abscess via digital rectal examination, anorectal ultrasound or MRI, and scheduled for incision and drainage or radical surgery;
3. The maximum diameter of the abscess cavity ≥ 2 cm, or with obvious abscess cavity formation;
4. Patients are willing and capable of participating in the pain management protocol, fully understand the significance of pain management, and can actively cooperate with study procedures;
5. No severe coagulation disorders.

Exclusion Criteria:

1. Complicated with specific infectious diseases such as Crohn's disease and tuberculosis;
2. Unclear source of postoperative pain, i.e., the origin of pain cannot be confirmed or the pain is unrelated to surgery;
3. Presence of definite contraindications, including drug allergy or inability to tolerate any pain management measures adopted in this trial;
4. Pregnant or lactating women;
5. Patients unable to cooperate with the study, such as those with cognitive impairment, history of mental illness, communication barriers and other conditions;
6. Patients with long-term analgesic medication use and established drug tolerance;
7. Complicated with uncontrolled cardiovascular and cerebrovascular diseases (NYHA cardiac function class Ⅲ-Ⅳ), hepatic and renal insufficiency (Child-Pugh class C or eGFR < 30 mL/min/1.73 m²), etc.;
8. Abscess secondary to rectal neoplasms, trauma or iatrogenic injury;
9. Severe postoperative complications (such as massive hemorrhage, sepsis) or concurrent infections at other sites;
10. Patients receiving only non-surgical treatments such as simple needle aspiration of pus.