Local anaesthetic to reduce pain of dental care under GA

Sadly a significant number of children are ether too anxious or require significant levels of dental treatment and have this undertaken under general anaesthesia (GA). This is associated with significant morbidity particularly post-operative pain. The issue of intra-operative local anaesthetic (LA) has been suggested as a method of reducing post-operative pain.

The aim of this review was to assess the effects of intraoperative local anaesthesia for reducing post-operative pain following general anaesthesia for dental treatment in children and young people aged 17 years or younger.

Methods

Searches were conducted in the Cochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, ISI Web of Science Conference Proceedings, the US National Institutes of Health Register (ClinicalTrials.gov), the metaRegister of Controlled Trials (mRCT) and the International Federation of Pharmaceutical Manufacturers & Associations (IFPMA) Clinical Trials Portal.

Randomised controlled trials in which local anaesthetic was given intra-operatively under general anaesthesia for dental treatment of children and young people aged 17 years or younger were considered. Two reviewers independently selected studies and abstracted data, with study quality being assessed using the Cochrane Risk of Bias tool. Analysis was conducted following standard Cochrane methodology.

Results

14 trial involving 1152 patients were included.
4 studies were considered to be at low risk of bias, 7 at unclear risk and 3 at high risk.
Due to clinical heterogeneity in the delivery method of the local anaesthetic and variation in supplementary analgesics and follow up the studies could not be pooled.
In 7 studies where LA was delivery by infiltration (very low quality body of evidence). The results were equivocal. There was a decrease in bleeding and increase in soft tissue damage in the LA groups, but we did not judge this to be clinically significant.
In 2 studies where administration of LA was by intra-ligamental injection (very low quality body of evidence) there was no difference in mean pain scores, and they did not report any soft tissue damage.
One 3-armed study (very low-quality body of evidence, 54 participants analysed, overall high risk of bias) compared the effects of intra-ligamental and infiltration LA injection with no treatment. There was no evidence of a mean difference in pain, distress, or postoperative anxiety among the three groups.
4 studies (very low quality body of evidence) evaluated the effects of topical LA compared with no treatment or placebo. One study (unclear risk of bias) with a no-treatment comparator reported lower mean pain in the LA group; all other studies reported no difference in mean pain scores. Two studies reported on bleeding (unclear risk of bias): One study reported a clinically insignificant increase in bleeding with no treatment; the other reported no difference.
None of the studies reported on participant or child satisfaction.

Conclusions

The authors concluded:-

In this review, it was difficult to reach firm conclusions as to the benefit of using local anaesthetic for dental treatment under general anaesthesia. The information reported in the included studies was comprehensive and applicable to the review question, but ultimately it was not sufficient to address the objective of the review. We were unable to pool the included studies in a meta-analysis because of substantial variation in outcome measures, interventions, and treatment types. The use of supplementary analgesia further obscured the effect of local anaesthetics.

Based on the literature review and the results of this review, we recommend further randomised controlled trials that minimise bias through adequate allocation concealment and blinding of participants and assessors, and assess the effect of intraoperative local anaesthetic on the volume and type of anaesthetic used and on the cardiovascular system in participants receiving supplementary analgesics as well. Researchers should give consideration to the impact of any changes on the health and well-being of the participant and report baseline measures of pain or distress, or both, and preoperative anxiety.

Commentary

This review has followed the usually Cochrane methodological approaches and has identified a number of trials addressing the question. Unfortunately they are all relatively small and of limited quality and have looked a range of delivery methods and outcome measure which has prevented pooling. Consequently there is a need for high quality randomised trials to be conducted to asses whether there is a benefit to using LA for dental treatment under general anaesthesia.