Gustavo Feriani, Eric Hatanaka, Maria Regina Torloni, Edina MK da Silva

Postoperative pain is a barrier to the quality of paediatric care, the proper management of which is a challenge. Acute postoperative pain often leads to adverse functional and organic consequences that may compromise surgical outcome. Cleft lip is one of the most common craniofacial birth defects and requires surgical correction early in life. As expected after a surgical intervention in such a sensitive and delicate area, the immediate postoperative period of cleft lip repair may be associated with moderate to severe pain. Infraorbital nerve block associated with general anaesthesia has been used to reduce postoperative pain after cleft lip repair. To assess the effects of infraorbital nerve block for postoperative pain following cleft lip repair in children. We searched the following databases: Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library, Issue 6, 2015), MEDLINE, EMBASE, and Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) from inception to 17 June 2015. There were no language restrictions. We searched for ongoing trials in the following platforms: the metaRegister of Controlled Trials; ClinicalTrials.gov (the US National Institutes of Health Ongoing Trials Register), and the World Health Organization International Clinical Trials Registry Platform (on 17 June 2015). We checked reference lists of the included studies to identify any additional studies. We contacted specialists in the field and authors of the included trials for unpublished data. We included randomised controlled clinical trials that tested perioperative infraorbital nerve block for cleft lip repair in children, compared with other types of analgesia procedure, no intervention, or placebo (sham nerve block). We considered the type of drug, dosage, and route of administration used in each study. For the purposes of this review, the term 'perioperative' refers to the three phases of surgery, that is preoperative, intraoperative, and postoperative, and commonly includes ward admission, anaesthesia, surgery, and recovery. Two review authors (GF and EH) independently identified, screened, and selected the studies, assessed trial quality, and performed data extraction using the Cochrane Pain, Palliative and Supportive Care Review Group criteria. In case of disagreements, a third review author (EMKS) was consulted. We assessed the evidence using Grading of Recommendations, Assessment, Development and Evaluation (GRADE). We included eight studies involving 353 children in the review. These studies reported different types of interventions (lignocaine or bupivacaine), observation times, and forms of measuring and describing the outcomes, making it difficult to conduct meta-analyses. In the comparison of infraorbital nerve block versus placebo, there was a large effect in mean postoperative pain scores (our first primary outcome) favouring the intervention group (standardised mean difference (SMD) -3.54, 95% confidence interval (CI) -6.13 to -0.95; very low-quality evidence; 3 studies; 120 children). Only one study reported the duration of analgesia (in hours) (second primary outcome) with a difference favouring the intervention group (mean difference (MD) 8.26 hours, 95% CI 5.41 to 11.11; very low-quality evidence) and less supplemental analgesic requirements in the intervention group (risk ratio (RR) 0.05, 95% CI 0.01 to 0.18; low-quality evidence). In the comparison of infraorbital nerve block versus intravenous analgesia, there was a difference favouring the intervention group in mean postoperative pain scores (SMD -1.50, 95% CI -2.40 to -0.60; very low-quality evidence; 2 studies; 107 children) and in the time to feeding (MD -9.45 minutes, 95% CI -17.37 to -1.53; moderate-quality evidence; 2 studies; 128 children). No significant adverse events (third primary outcome) were associated with the intervention, although three studies did not report this outcome. Five out of eight studies found no unwanted side effects after the nerve blocks. Overall, the included studies were at low or unclear risk of bias. The reasons for downgrading the quality of the evidence using GRADE related to the lack of information about randomisation methods and allocation concealment in the studies, very small sample sizes, and heterogeneity of outcome reporting. There is low- to very low-quality evidence that infraorbital nerve block with lignocaine or bupivacaine may reduce postoperative pain more than placebo and intravenous analgesia in children undergoing cleft lip repair. Further studies with larger samples are needed. Future studies should standardise the observation time and the instruments used to measure outcomes, and stratify children by age group.