Rectus sheath block (RSB) is used for postoperative pain relief in patients undergoing abdominal surgery with a midline incision. It has proved to be effective in preoperative block, but it has not been previously compared with postoperative block. The aim of the present study is to evaluate postoperative pain, sleep quality and changes in the cytokine levels of patients undergoing gynaecological surgery with RSB performed preoperatively versus postoperatively.

Rectus sheath block (RSB) is used for postoperative pain relief in patients undergoing abdominal surgery with a midline incision. It has proved to be effective in preoperative block, but it has not been previously compared with postoperative block. The aim of the present work is to evaluate the postoperative sleep quality and changes in cytokines of patients undergoing gynaecological operation with RSB preoperatively or postoperatively.

Methods/Design This study is a prospective, randomized, controlled (randomized, parallel group, concealed allocation), double-blinded trial. All patients undergoing transabdominal gynaecological operation will be randomized 1:1 to the treatment intervention with general anaesthesia as an adjunct to RSB preoperatively or postoperatively. The objective of the trial is to evaluate the postoperative sleep quality and changes in cytokines of patients undergoing hysterectomy with RSB preoperatively (n=32) or postoperatively (n=32). All of the patients, irrespective of group allocation, will receive patient-controlled intravenous analgesia with oxycodone.

The primary objective is to compare the interval between leaving the post-anaesthesia care unit and receiving the first PCIA bolus injection on the first postoperative night between patients who receive preoperative versus postoperative RSB. The secondary objectives will be to compare (1) cumulative oxycodone consumption at 24 h after surgery; (2) postoperative sleep quality, as measured using a BIS-Vista monitor during the first night after surgery; and (3) cytokine levels (interleukin-1, interleukin-6, tumour necrosis factor-α and interferon-gamma) during surgery and at 24 and 48 h postoperatively.

The inclusion criteria are as follows: (1) an age of 18 to 65 years old; (2) scheduled to undergo elective midline incision transabdominal gynaecological surgery for benign mass; and (3) American Society of Anaesthesiologists (ASA) risk classification I-II.

The exclusion criteria are as follows: (1) patient refusal; (2) known hypersensitivity to the study medication (ropivacaine); (3) long-term use of opioids; (4) liver or renal insufficiency; (5) a history of psychiatric or neurological disease; (6) deafness; (7) previous open surgery; (8) regular use of acetaminophen, nonsteroidal anti-inflammatory drugs, corticosteroids, or antiemetics; and (9) a preoperative Pittsburgh Sleep Quality Index (PSQI) global score of higher than 6