Types of studies

Randomised controlled trials (RCTs) and cluster‐randomised controlled trials. If a cluster‐randomised controlled trial includes only two clusters, we will exclude it. We will exclude quasi‐randomised controlled trials.

Types of participants

We will include all adult and child patients undergoing septal surgery in any setting for any indication. We will include studies in which participants also underwent turbinate surgery. We will exclude studies in which participants also underwent FESS.

Types of interventions

Anaesthesia will include local injection, local application via nasal packing and sphenopalatine ganglion block using commercially available agents. We will define a sphenopalatine ganglion block as a regional block performed via the oral cavity and through the descending/greater palatine canal. We will exclude discontinued agents. Local anaesthetic agents have different durations of action and we will classify them as short‐ or long‐acting as follows:

• short‐acting: duration of action of less than four hours, e.g. procaine, chloroprocaine, tetracaine, lidocaine, mepivacaine and prilocaine;

• long‐acting: duration of action of four hours or more, e.g. bupivacaine, levobupivacaine and ropivacaine (Miller 2011).

We will exclude head‐to‐head RCTs comparing the same local anaesthetic agent with a different concentration.

We will consider the following main comparison pairs:

• local injection versus no treatment/placebo;

• local application via nasal packing versus no treatment/placebo;

• sphenopalatine ganglion block versus no treatment/placebo.

In addition, we will also consider the following comparison pairs:

• local injection plus local application via nasal packing versus no treatment/placebo;

• local injection plus sphenopalatine ganglion block versus no treatment/placebo;

• local application via nasal packing plus sphenopalatine ganglion block versus no treatment/placebo;

• local injection versus local application via nasal packing;

• local injection versus sphenopalatine ganglion block;

• local application via nasal packing versus sphenopalatine ganglion block.

Types of outcome measures

We will analyse the following outcomes in the review, but we will not use them as a basis for including or excluding studies.

We will consider pain duration within the postoperative timeframes of the first 12 hours, 24 hours and 48 hours or more.

Electronic searches

Published, unpublished and ongoing studies will be identified by searching the following databases from their inception:

• Cochrane Register of Studies ENT Trials Register (search to date);

• Cochrane Central Register of Controlled Trials (CENTRAL, current issue), Ovid MEDLINE (1946 to date), Ovid MEDLINE (In‐Process & Other Non‐Indexed Citations);

• PubMed (as a top‐up search for searches in Ovid MEDLINE));

• Ovid EMBASE (1974 to date);

• EBSCO CINAHL (1982 to date);

• Ovid CAB abstracts (1910 to date);

• LILACS (search to date);

• KoreaMed (search to date);

• IndMed (search to date);

• PakMediNet (search to date);

• Web of Knowledge, Web of Science (1945 to date);

• ClinicalTrials.gov (www.clinicaltrials.gov) (search via the Cochrane Register of Studies to date);

• International Clinical Trials Registry Platform (ICTRP) (search to date);

• ISRCTN (www.isrctn.com) (search to date);

• Google Scholar (search to date);

• Google (search to date).

The subject strategies for databases will be modelled on the search strategy designed for CENTRAL (Appendix 1). Where appropriate, these will be combined with subject strategy adaptations of the highly sensitive search strategy designed by Cochrane for identifying randomised controlled trials and controlled clinical trials (as described in the Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0, Box 6.4.b. (Handbook 2011)).

Searching other resources

We will scan the reference lists of identified publications for additional trials and contact trial authors if necessary. In addition, the Trials Search Co‐ordinator will search PubMed, TRIPdatabase, The Cochrane Library and Google to retrieve existing systematic reviews relevant to this systematic review, so that we can scan their reference lists for additional trials. We will search for conference abstracts using the Cochrane ENT Trials Register and EMBASE.

Selection of studies

Two review authors (AK and ToF) will independently screen any titles and abstracts from the searches. We will obtain the full text of studies that potentially meet the eligibility criteria. The same two authors will independently assess the eligibility of the studies from the full text. We will resolve disagreements by discussion and we will consult a third author (TaF) if disagreement is not resolved by discussion.

Data extraction and management

Two review authors (AK and ToF) will independently extract data using a standardised data extraction form developed by the review authors. We will resolve disagreement by discussion and consult a third author (TaF) if disagreement is not resolved. The extraction form will include the following information:

• source: year of publication, citation and contact details;

• method: study design, study duration, sequence generation, concealment and blinding;

• study eligibility criteria, including participant population and surgery;

• participants: total number, setting, age, sex and country;

• interventions: total number of intervention groups, type of intervention, type of local anaesthetic drug, and use and type of vasoconstrictors;

• confounding factors: usage of perioperative corticosteroid, type of anaesthesia (local or anaesthesia) and type of nasal packing;

• outcome/measurement;

• miscellaneous: funding source and reference to relevant studies.

Assessment of risk of bias in included studies

TaF and YK will independently assess the risk of bias of the included trials and consider the following, as noted in theCochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (Handbook 2011):

• sequence generation;

• allocation concealment;

• blinding of participants and personnel;

• blinding of outcome assessment;

• incomplete outcome data;

• selective outcome reporting; and

• other sources of bias.

We will use the Cochrane 'Risk of bias' tool in RevMan 5.3 (RevMan 2014), which involves describing each of these domains as reported in the trial and then assigning a judgement about the adequacy of each entry: 'low', 'high' or 'unclear' risk of bias.

Measures of treatment effect

For dichotomous outcomes, we will calculate the risk ratios of observable differences between the interventional and comparative groups, with 95% confidence intervals. For continuous outcomes, we will calculate the mean differences and 95% confidence intervals. If a continuous outcome is measured using different scales (visual analogue scale (VAS), numerical rating scale or verbal rating scale), we will calculate standardised mean differences and 95% confidence intervals and perform a meta‐analysis.

Unit of analysis issues

If we include cluster‐RCTs for meta‐analysis, we will use the intracluster correlation co‐efficient (ICC) to adjust the sample sizes of the data available from the trials; if not, we will use the ICC from a similar trial or study with a similar population using the methods in the Cochrane Handbook for Systematic Reviews of Interventions (Handbook 2011). We will use generic inverse‐variance methods to perform meta‐analysis to estimate the effect and standard error of the trial. If we use an ICC from other sources, we will conduct sensitivity analysis to check the effect of variation in the ICC. If little heterogeneity exists, we will try to combine individual RCTs and cluster‐RCTs. We will also conduct sensitivity analysis to investigate the effects of the randomisation unit.

When we include multiple control (placebo and no intervention) RCTs, we will combine groups to create single pair‐wise comparisons. If included studies have multiple interventions, we will analyse the relevant intervention group only. If there are more than two intervention groups, we will split the control group into two or more groups with smaller sample sizes to make reasonably independent comparisons.

Dealing with missing data

We will specify levels of attrition for included trials. We will perform sensitivity analysis to check the impact of including trials with high levels of attrition data on the intervention effect. For missing or unavailable data, we will contact the study authors. For data synthesis, we will use available case analysis.

Assessment of heterogeneity

We will use the I² statistic to assess the magnitude of heterogeneity (Higgins 2002). We will conduct pre‐specified subgroup analysis if substantial heterogeneity exists (defined as an I² value greater than 60% and either Tau² is greater than zero, or there is a low P value (less than 0.10) in the Chi² test for heterogeneity).

Assessment of reporting biases

We will assess the possibility of publication bias and other possible biases using Egger's asymmetry test (Egger 1997). If publication bias is suspected and there are at least 10 studies included, we will use funnel plots to identify bias.

Data synthesis

We will conduct meta‐analysis using forest plots with the Review Manager software for those trials reporting similar outcome measures (RevMan 2014). We will use a fixed‐effect model to conduct meta‐analysis if the included studies are reasonably similar or have small sample sizes or few trials, but otherwise we will use a random‐effects model. We will present the results as the average treatment effect with a 95% confidence interval. If data from included studies are unsuitable for meta‐analysis due to unexplainable substantial heterogeneity, we will describe the findings of studies narratively.

Subgroup analysis and investigation of heterogeneity

We will undertake following subgroup analysis for the primary outcome:

• short‐acting anaesthetic agent versus long‐acting anaesthetic agent.

We will take into consideration several potential sources of heterogeneity. If statistical heterogeneity is identified in the primary outcome measures, we will undertake the following subgroup analyses:

• use of vasoconstrictors versus no use of vasoconstrictors;

• septal surgery without turbinate surgery versus septal surgery with turbinate surgery;

• use of perioperative corticosteroid versus no use of corticosteroid;

• use of nasal packs versus no use of nasal packs.

Sensitivity analysis

We will conduct sensitivity analysis for the primary outcomes based on the 'Risk of bias' assessment effect from high attrition rates. We will perform the sensitivity analysis with or without trials with high attrition rates in the analyses to see if there is any difference in the overall results.