Study on Repeat Liposomal Bupivacaine for Post-Surgery Pain in Anal Fistula Patients.

Sun Yat-sen University

Status: Enrolling

Conditions: Anal Fistula

Treatments: Drug: A single dose of liposomal bupivacaine is administered at the conclusion of surgery without adjunctive analgesics, followed by a supplemental dose 72 hours postoperatively.

Study type: Interventional

Funder types: Other

Identifiers

NCT07081373

2025ZSLYEC-365

Details and patient eligibility

About

Anal Fistula refers to an abnormal infectious fistula tract between the anorectum and the perianal skin. The prevalence of anal fistula is approximately 8.6 cases per 100,000 individuals. It can occur at any age but is relatively more common in individuals aged 20-40 years, with a higher incidence in males than females.

Postoperative wound management is a critical component of the overall treatment for anal fistula patients. Regular postoperative wound care, such as dressing changes, can reduce recurrence rates, alleviate pain, and shorten hospitalization time. However, postoperative pain remains a major challenge in wound management following anal fistula surgery. This is largely attributed to inadequate current postoperative analgesic protocols.

With ongoing advancements in local anesthetics, liposomal bupivacaine has been applied for postoperative analgesia. It offers higher bioavailability and a prolonged half-life, providing up to 72 hours of sustained analgesic effect. Given the limitations of existing analgesic strategies for post-anal fistula surgery, developing more effective pain management approaches to reduce postoperative pain holds significant clinical importance.

Therefore, the investigators propose that a repeat-dosing strategy based on liposomal bupivacaine may provide superior postoperative pain control for anal fistula patients. To investigate this, the investigators designed a prospective, multicenter, randomized, open-label, controlled clinical trial. This study aims to evaluate the efficacy and safety of repeat-dose liposomal bupivacaine for postoperative analgesia following anal fistula surgery, thereby generating high-level evidence to support its clinical application in this context.

Enrollment: 408 estimated patients

Sex: All

Ages: 18 to 60 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Diagnosed with anal fistula and scheduled to undergo anal fistula surgery;
• Aged between 18 and 60 years;
• ASA (American Society of Anesthesiologists) physical status class I-II;
• Patient provides written informed consent after understanding the study protocol.

Exclusion criteria

• Anal fistula caused by specific etiologies (e.g., tuberculosis);
• Concurrent acute perianal skin infection;
• Poorly controlled diabetes (HbA1c >9%);
• Chronic use of corticosteroids;
• History of radiotherapy or chemotherapy within the past 2 weeks;
• Pregnancy or lactation;
• Hypersensitivity to local anesthetics or any component of the investigational drug;
• History of substance abuse, illicit drug use, or alcohol abuse;
• Use or planned use of non-opioid/opioid analgesics within 12 hours before/during surgery;
• Concurrent treatment with anticonvulsants, MAO inhibitors, antidepressants, neuromuscular blockers, or anticholinergics within 2 weeks prior to surgery;
• Severe hepatic/renal impairment, cardiopulmonary dysfunction, coagulation disorders, or comorbidities contraindicating surgery;
• History of severe psychiatric disorders or cognitive impairment;
• Sensory disorders (e.g., hyperalgesia) or preexisting pain interfering with postoperative pain assessment;
• Contraindications to amide-type local anesthetics, opioids, or propofol;
• Participation in investigational drug trials within 90 days prior to enrollment;
• Other clinical/laboratory conditions deemed by investigators to preclude trial participation.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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408 participants in 2 patient groups

Liposomal Bupivacaine Repeat Dosing Group

Experimental group

Description:

A single dose of liposomal bupivacaine is administered at the conclusion of surgery without adjunctive analgesics, followed by a supplemental dose 72 hours postoperatively.

Treatment:

Drug: A single dose of liposomal bupivacaine is administered at the conclusion of surgery without adjunctive analgesics, followed by a supplemental dose 72 hours postoperatively.

Liposomal Bupivacaine Single-Injection Group

No Intervention group

Description:

A single dose of liposomal bupivacaine is administered at the conclusion of surgery without adjunctive analgesics.