This will be an open, prospective, parallel-group, randomized controlled trial. Patients scheduled for complex anorectal surgery under general anesthesia will be enrolled, and the perioperative analgesia mode led by anesthesiologists will be established. Compared with the perioperative analgesia mode led by surgeons, the efficacy and safety of analgesia, quality of life and satisfaction of patients will be evaluated. This study is aimed at the feasibility and efficiacy of anesthesiologist-led treatment mode in the management of moderate and severe pain in patients after complex anorectal surgery.

Patients suffer from moderate to severe postoperative pain up to 14 days after anorectal surgery. To establish an anesthesiologist-led multidisciplinary team for postoperative analgesia in anorectal surgery under short and complex general anesthesia. However, the implementation of perioperative analgesia in anorectal surgery has not been paid enough attention. This study aims to establish the application of anesthesiologist-led multidisciplinary postoperative analgesia in anorectal surgery under general anesthesia.

Objectives: Patients undergoing complex anorectal surgery under general anesthesia will be randomly divided into two groups: anesthesiologist-led group (Anes Group) and surgeon-led group (Surg Group).

Interventions: Both groups will receive general anesthesia combined with long-term local anesthesia, postoperative patient controlled intravenous analgesia (PCIA) and multi-mode analgesia including laxatives and antibiotics. In Anes Group, patients receive postoperative analgesia following the protocol established by the anesthesiologist, continuous with intraoperative analgesic protocol. In Surg Group, patients will be given postoperative analgesia and follow-ups by the traditional mode formulated by the surgeons and the consultant of the pharmacists. The postoperative PCIA analgesic formula and the choice of analgesics are same in the two groups.

Follow-ups and outcomes: Patients will be followed-up till total recovery after surgery. Primary outcome is the time of recovery of work and life after surgery day, defined as not requiring any additional medication and resuming full pre-operative work life content. Secondary outcomes include opioid use after surgery, the degree of pain during defecation and rest pain, the adverse reactions related to analgesia, satisfaction, the time of ambulation, the length of hospital stay.

The purpose of this study was to evaluate the feasibility of anesthesiologist-led care model in complex anorectal surgery and to optimize the perioperative analgesia in anorectal surgery.

Inclusion Criteria:

1. American Society of Anesthesia (ASA) grading I-III
2. ≥18 years old
3. Patients scheduled for complex anorectal surgery under general anesthesia, e.g., mixed hemorrhoidectomy/sclerosing agent injection/ligation, radical anal fistula resection, peri-anal abscess incision and drainage

Exclusion Criteria:

1. Informed consent not obtained
2. Allergic to general anesthetics, hydromorphone, non-steroidal anti-inflammatory drugs and other related ingredients
3. Opioid abuse or pathological pain that requires long-term analgesic treatment
4. History of severe asthma attack and acute phase of asthma
5. Moderate or above ventilatory function or diffusion dysfunction
6. Liver dysfunction reached Child B grade; Renal insufficiency reached chronic kidney disease (CKD) stage IV
7. Gastric retention and paralytic ileus
8. Pregnant and lactating patients

This is an open label trial.