Objectives:

To examine the efficacy and safety of electroacupuncture (EA) combined with auricular acupuncture (AA) in reducing post-operative pain in patients following abdominal surgery for gynecological diseases.

Hypothesis:

Acupuncture is effective and safe to reduce postoperative pain during the first 5 days following surgery as compared to a sham control.

Design and strategy:

This is a randomized, placebo-controlled, subject- and assessor-blind trial. Seventy-two subjects will be recruited and randomized (in 1:1 ratio) to receive either acupuncture treatment or sham control. Subjects in both groups will undergo standard operation procedure and receive post-operative analgesics based on usual care.

Study instrument:

A 10-point pain Numerical Rating Scale (NRS) will be employed as a primary outcome assessment.

Intervention:

Subjects in the treatment group will receive EA combined with AA within two hours before operation, post-operation upon arrival to the ward and once a day for the subsequent 5 days. Subjects in the control group will receive non-invasive sham procedure in the same schedule.

Main outcome measures:

Primary outcome: NRS pain scores will be measured upon recovery, hourly at 6 hours after surgery, then 4-hourly until day 2, 6-hourly until day 3 and once daily until discharge.

Secondary outcome:

Morphine consumption, post-operative syndromes, quality of recovery questionnaire, SF-6D, EQ-5D-5L and adverse events will be documented and compared between groups.

Data analysis: Pain intensity during the first 5 days will be calculated by Area Under the Curve (AUC) of NRS pain scores. AUC between the two groups will be compared by Student's T-test.

Expected outcome: AUC of the acupuncture group is expected to be significantly lower than sham acupuncture group.

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status I to III
• Eligible for laparotomy with midline incision for gynaecological neoplasm including ovarian mass, uterine mass and cervical lesions
• Age 18 years or above
• Ability to understand the nature of the study and willing to give informed consent
• Capable of providing responses during outcome measurement

Exclusion Criteria:

• Having chronic pain and using any medication in addition to the anaesthetic and analgesia prescribed prior to surgery that would be expected to affect the dosage of postoperative analgesia
• History of or current alcohol or drug abuse
• Impaired renal function, defined as preoperative serum creatinine level over 120µmol/L
• Impaired hepatic function, defined as preoperative serum albumin level below 30g/L
• Impaired or retarded mental state and not able to sign the consent
• Not self-ambulatory before operation
• Difficulties in using patient-controlled analgesia
• BMI > 35kg/m2
• Infection observed at the acupoint sites
• History of acupuncture experience in the previous 12 months
• History or clinical evidence of valvular heart defects, heart failure, atrial fibrillation or bleeding disorders or are fitted with cardiac pacemaker or taking anticoagulant drugs