Supplementary intracameral lidocaine for phacoemulsification under topical anaesthesia: A meta-analysis of randomized control trials
Methodological quality of the review: Low confidence
Author: Ezra DG, Nambiar A, Allan BD.
Region: Details not provided
Sector: Topical anaesthesia, supplementary intracameral lidocaine, phacoemulsification.
Sub-sector: None Specified
Equity focus: None Specified
Review type: Effectiveness review
Quantitative synthesis method: Meta-analysis
Qualitative synthesis methods: Not applicable
Background
Currently there are several types of anaesthetics used during cataract surgery including topical anaesthesia, a cost-effective intervention that is commonly used and provides for more rapid post-operative visual recovery. Patients who undergo cataract surgery under topical anaesthesia often report that there are certain points of discomfort during the surgery. As a result, topical anaesthesia can be supplemented with intracameral anaesthesia to further reduce discomfort. Authors note that data which compares topical anaesthesia alone with topical anaesthesia with intracameral anaesthesia for phacoemulsification (Phaco) have produced conflicting outcomes and conclusions.
Research objectives
The primary objective of this of this systematic review was to assess pain during surgery and patient satisfaction in topical anaesthesia alone versus topical anaesthesia versus with intracameral anaesthesia for phacoemulsification. The secondary objectives were to assess adverse effects and complications attributable to choice of anaesthesia and need for additional anaesthesia during surgery.
Main findings
Eight studies were identified for inclusion in the systematic review, all of which were randomized control trials comparing topical anaesthesia alone with topical anaesthesia and intracameral lidocaine.
Seven studies in total measured pain or discomfort during surgery and concluded that there was a statistically significant benefit resulting from the use of intracameral preservative-free 1% lidocaine (P= 0.001). Two of the studies which measured postoperative pain did not identify any benefit (after surgery) of the supplementation of intracameral 1% lidocaine (P =0.51). Only one study measured patient satisfaction and no significant difference was found between topical anaesthesia alone and topical with intracameral groups.
There was no significant difference between topical alone and topical with intracameral anaesthesia groups when analysing intraoperative adverse effects or the need for additional anaesthesia during surgery. It should be noted that types of adverse effects and other secondary outcome measures were often poorly defined within the studies and heterogeneous, meaning that conclusions should be interpreted with caution.
The authors concluded that intraoperative pain during cataract surgery under topical anaesthetic is reduced by intracameral lidocaine. Although the supplementation of intracameral lidocaine statistically reduced intraoperative pain, it was not possible to conclude if this translated into clinical significance since treatment effect was small. They also noted that prospective trials were needed in this area and should adopt the 10-point pain scale that was adopted by many of the included studies in this review and should clearly define criteria for administration of additional anaesthesia and types of intraoperative complications. Future studies should record surgery time and clinical significance of data should be further addressed.
Methodology
Selected studies were restricted to randomized control trials which compared topical anaesthesia alone with topical anaesthesia and intracameral lidocaine. Primary outcome measures included 1) measures of pain or discomfort during surgery 2) measures of pain or discomfort after surgery and 3) measures of patient satisfaction with anaesthesia. Secondary outcomes included adverse effects, need for additional anaesthesia during surgery, intraoperative complications and surgeon satisfaction.
The review is based on a search of literature on the Cochrane Register of Controlled Trials, MEDLINE, Excerpta Medica database and LILACS up to June 2006. No language restriction was imposed and reference lists of relevant trials were checked. Titles and abstracts resulting from the searches were independently reviewed by two of the authors, although methods used to extract data was not reported within the review.
Authors conducted a meta-analysis of the data from the eight included studies and heterogeneity between trial results was explored using a chi-square test. Assessment of trial quality and data synthesis was performed in accordance with the Cochrane Handbook for Systematic Reviews and Interventions, although the trial quality of each study was not specifically reported in the review.
Applicability/external validity
Although authors identified a statistical benefit for the use of supplementary intracameral lidocaine, it was noted that it was unclear how this translated into a clinical benefit since the treatment effect was small and authors noted that there was no difference in patient satisfaction between treatment and control groups.
Geographic focus
Authors did not address the geographical location of the included studies and it was not possible to draw conclusions about the applicability of findings of different settings.
Quality assessment
Authors conducted a comprehensive search of the literature, avoiding language bias. Although selection bias was also avoided by the authors, it was not clear if data extraction was also conducted by two reviewers independently. Therefore, we could not be confident that characteristics and results of included studies were reliably reported.
Authors did not provide a summary of the characteristics of included trials including outcomes, interventions, participants, and the trial quality of each study was not specifically reported in the review. The review, therefore, did not make clear which evidence is subject to low or high risk of bias. Thus, there was a low confidence in the conclusions about the effects of this study.
