Xu 2017

Methods	Clinical RCT Sequence generation by computer‐generated random numbers Follow‐up for 3 months
Participants	Subjects: 71 adults in a military hospital in China Operation: thoracolumbar spinal surgery 2 groups, size: 35/36 Age (± SD), group 1, 2: 51.91 (11.44), 49.06 (11.20) Men/women, group 1, 2: 19/16, 19/17 Exclusion criteria: a history of cardiopulmonary disease, coagulation and merging with multiple injuries
Interventions	Group 1 (ropivacaine): continuous wound infusion with ropivacaine was used as primary analgesia. This group received an initial wound infiltration with 6 mL 1% ropivacaine (100 mg; AstraZeneca AB, Sweden) and followed by continuous infusion with 0.33% ropivacaine via a double lumen catheter system at a rate of 5 mL/h (disposable postoperative local analgesia system, Beijing Heng Yuan Tongji Medical Technology Corporation, China) for 48 h. Participants in this group did not receive postoperative IV continuous constant‐dose analgesia (ICCA) for pain control. Participants were premedicated with phenobarbital 100 mg and atropine 0.5 mg, 30 min before the induction of anesthesia. After baseline measurements of heart rate, noninvasive blood pressure, respiratory rate and oxygen saturation, each participant was preoxygenated for 3 min before induction. All participants received the target‐controlled infusion with propofol 2‐ 3 μg/mL using the Marsh pharmacokinetic model and remifentanil at 3 ng/mL to 4 ng/mL using the Minto pharmacokinetic model for induction. Following the induction of anaesthesia, cisatracurium 0.15 mg/kg was given as an IV injection. After tracheal intubation, mechanical ventilation was initiated with 100% oxygen and adjusted to maintain the end tidal carbon dioxide tension between 35 mmHg and 45 mmHg. Intermittent bolus injection of cisatracurium was used to maintain full muscle relaxation. At the end of surgery, residual neuromuscular block was reversed, if needed, with a mixture of atropine and neostigmine. Participants were given pentazocine 60 mg when surgery was completed prior to extubation. All participants expanded on the use of the supplementary analgesic (flurbiprofen 50 mg IV injection) if necessary (VAS > 4) Group 2 (control): exactly the same as described above except there was no wound infiltration with ropivacaine. Additionally, this group relied on ICCA for postoperative pain control involving flurbiprofen axetil 150 mg, pentazocine 240 mg and palonosetron 0.5 mg in 100 mL normal saline, at a rate of 2 mL/h. All participants expanded on the use of the supplementary analgesic (flurbiprofen 50 mg IV injection) if necessary (VAS > 4) Adjuvants: none Immediate post‐op pain control: no improvement
Outcomes	Dichotomous: pain vs no pain Continuous: none Other reported: demographic and operation data including disease, date of birth, gender, operating time, preoperative VAS, perioperative remifentanil and propofol doses, and length of surgical incision, pain score at rest during first 48 h postoperative using VAS, and Ramsay scores, times of rescue analgesia requests, incidence of postoperative nausea and vomiting, antiemetic therapy requirements and incidence of pruritus (participants were asked about the desire to scratch) at 2, 4, 6, 12, 24, 36 and 48 h postoperatively
Notes	We were unable to obtain additional information about randomization and blinding methods from the study author. Funding sources: funding for the study was provided by Guangzhou General Hospital of Guangzhou Military Command. Conflicts of interest: "all the authors declare they have no competing of interests."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"All participants were randomly assigned using a computer‐generated random number table."
Allocation concealment (selection bias)	Unclear risk	Concealment of allocation not described
Blinding of participants and personnel (performance bias) All outcomes	High risk	No sham was employed and blinding of participants/personnel not described
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding of outcome assessors not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	"All enrolled patients successfully completed the study and were included in the main analysis."
Selective reporting (reporting bias)	Low risk	No subgroup analysis was performed
Null bias	High risk	"There were no significant differences in the pain level between the two groups"