Liposomal Bupivacaine vs Ropivacaine for Post-hemorrhoidectomy Analgesia

Liposomal Bupivacaine Versus Ropivacaine for Wound Infiltration Analgesia After Milligan-Morgan Open Hemorrhoidectomy: A Randomized Controlled Trial

This is a single-center, prospective, randomized, double-blind controlled trial comparing the analgesic efficacy, quality of recovery, and safety of perianal wound infiltration with multivesicular liposomal bupivacaine (266 mg) versus ropivacaine hydrochloride (200 mg) in patients undergoing Milligan-Morgan open hemorrhoidectomy under spinal anesthesia. Both solutions are diluted to a total volume of 30 mL and infiltrated at six predefined perianal positions at the end of surgery. The primary outcome is the resting visual analog scale (VAS) pain score at 24 hours after surgery. Secondary outcomes include resting and movement-evoked VAS pain scores at 4, 6, 12, 24, and 48 hours, cumulative rescue analgesic consumption during postoperative days 1-3, Quality of Recovery-40 (QoR-40) scores on postoperative days 1-3, and adverse events within 72 hours after surgery.

Milligan-Morgan open hemorrhoidectomy is associated with substantial postoperative pain due to rich somatic innervation of the perianal region, wound exposure, anal sphincter spasm, and stimulation during defecation. Optimizing postoperative analgesia is critical for enhanced recovery. Local wound infiltration with ropivacaine is commonly used but provides limited duration of analgesia. Liposomal bupivacaine, formulated with a multivesicular liposomal delivery system, enables sustained release of bupivacaine at the injection site and may prolong local analgesia. However, high-quality comparative evidence between liposomal bupivacaine and ropivacaine for wound infiltration after open hemorrhoidectomy remains limited.

This single-center, prospective, randomized, double-blind controlled trial enrolled patients aged 18-60 years with grade III-IV internal hemorrhoids or mixed hemorrhoids scheduled for elective Milligan-Morgan open hemorrhoidectomy at Tongliao People's Hospital between November 2025 and May 2026. Patients were randomized 1:1 to receive perianal wound infiltration with either 266 mg of liposomal bupivacaine or 200 mg of ropivacaine hydrochloride, both diluted to 30 mL with normal saline and divided into six 5-mL aliquots infiltrated at six predefined perianal clock-face positions. All patients received spinal anesthesia with 15 mg of 0.5% hyperbaric bupivacaine. Rescue analgesia with oral diclofenac sodium 50 mg was provided when VAS pain score was ≥4.

The primary outcome is resting VAS pain score at 24 hours postoperatively. Secondary outcomes include resting and movement-evoked VAS pain scores at 4, 6, 12, 24, and 48 hours, cumulative diclofenac sodium consumption during postoperative days 1-3, QoR-40 total scores on postoperative days 1-3, and adverse events (nausea and vomiting, rash, lower-extremity numbness or weakness, local anesthetic systemic toxicity, perianal hematoma, surgical-site infection) within 72 hours.

Inclusion Criteria:

• 1. Aged 18-60 years, irrespective of sex 2. Diagnosed with grade III-IV internal hemorrhoids or mixed hemorrhoids based on specialist examination and scheduled to undergo elective Milligan-Morgan open hemorrhoidectomy 3. American Society of Anesthesiologists (ASA) physical status I-III 4. Body mass index (BMI) of 18.0-30.0 kg/m² 5. Able to understand and complete the pain and quality-of-recovery assessments and willing to participate in the study

Exclusion Criteria:

1. Concomitant chronic low back or leg pain, anal fissure, perianal abscess, or other persistent painful conditions 2. Pregnancy, breastfeeding, or plans to become pregnant in the near future 3. Known allergy to bupivacaine, ropivacaine, or any other medication used during the study 4. Long-term regular use of opioids or use of analgesic medications within 48 hours before surgery 5. Obstructive sleep apnea syndrome or severe cardiovascular, cerebrovascular, or pulmonary disease considered to significantly increase risks associated with neuraxial anesthesia or postoperative analgesia 6. Psychiatric or cognitive impairment that precludes completion of study assessments 7. Any other condition that, in the investigator's judgment, renders the patient unsuitable for participation

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