Revised Translation (Academic English):

As one of the most prevalent anorectal disorders, mixed hemorrhoids continue to rely on the Milligan-Morgan hemorrhoidectomy as the gold-standard surgical approach. While this technique demonstrates well-established efficacy, managing acute postoperative pain-particularly during the critical 24-72-hour peak pain window-remains a persistent clinical challenge. Recent advancements in multimodal analgesia have highlighted the potential of local nerve blockers, with methylene blue (MB) gaining scientific interest due to its prolonged analgesic properties. This randomized controlled study systematically evaluates the synergistic analgesic effects of gradient concentrations of MB combined with ropivacaine (ROP) following Milligan-Morgan procedures. Therapeutic safety profiles were validated through dual-dimensional monitoring of Visual Analog Scale (VAS) scores and complication rates, aiming to establish evidence-based optimal dosing protocols and refine perioperative pain management strategies.

Inclusion Criteria:

1. Aged between 18 and 75 years.
2. Diagnosed with Grade III-IV hemorrhoids according to the Goligher classification.
3. Scheduled to undergo standard Milligan-Morgan hemorrhoidectomy.
4. Procedure performed under spinal anesthesia alone.

Exclusion Criteria:

1. Pregnancy or lactation.
2. Current immunotherapy or coagulopathies.
3. Contraindications to any protocol-specified agents (e.g., history of severe allergic reactions to methylene blue or ropivacaine).
4. Concurrent anorectal pathologies (e.g., perianal abscess, anal fistula, fecal incontinence).
5. Comorbid systemic conditions (e.g., cardiac/hepatic/renal insufficiency, diabetes mellitus, coagulopathy, peptic ulcer disease).
6. Incomplete perioperative documentation.
7. Inability to comply with follow-up protocols.