Commentary

Pain is a subjective experience, combining the perception of a noxious stimulus with a strong emotional component. A review of the recent literature from paediatric surgical disciplines suggests that local analgesia, via infiltration and block techniques, reduces postoperative pain in children undergoing surgery under GA.1 The dental literature is less conclusive. This study aimed to examine this issue.

A double-blind technique was used in this study of 142 children aged 4–12 years (median, 6 years) undergoing extraction of between one and 10 teeth (mean, 5.8 teeth) under GA. The children were randomised to receive either 2 ml of 2% lidocaine with 1:200 000 adrenaline or 2 ml of 0.9% normal saline as placebo injected by buccal infiltration adjacent to the site of dental extraction, after induction of GA. Details of the sample size calculation and randomisation method were reported. Although the number of participants for whom data were incomplete was reported, no reasons were given. The main clinical outcome measures were postoperative pain and distress and lip/ cheek biting over the first 24 h period. The authors used self-report of pain, choosing a reliable, valid paediatric visual analogue pain scale, in recognition of the significant personal and emotional component of the pain experience.2 All postoperative measures were recorded by the same investigator but it is not clear if the same dentist and anaesthetist treated all the participants.

The authors based their decision to use infiltration rather than regional block analgesia for lower extractions on a paper examining pain control in umbilical hernia repair.3 The local anaesthesia technique used in that study, long-lasting bupivicaine administered at completion of surgery, may not be directly comparable with the pre-operative lidocaine used in this study. No palatal local anaesthesia was used for upper extractions. Therefore the level of local anaesthesia fell short of that which would be given for exodontias in the awake child but mirrors that provided in most UK centres to children undergoing extractions under GA.

Disappointingly, the study found no statistically significant difference in pain or distress scores between the local anaesthesia and placebo groups. Indeed, high numbers of children (approx. one third of both groups) described “severe” or “very severe” pain 30 min after surgery. It is not clear whether these were the same children who had more than seven teeth extracted or were younger than 7 years old. The authors do not discuss the potential influence of emergence agitation on early postoperative assessment of distress in children, although the propofol/ sevoflurane general anaesthetic technique used may have minimised such an effect.4

Postoperative pain and distress following exodontia under GA is undoubtedly multifactorial, with outcome being influenced by factors such as pre-operative anxiety levels, systemic5 and local analgesia interventions, and the influence of GA.6 It would be ethically difficult to examine each factor independently.

This well-designed RCT is a useful addition to the sparse paediatric dental literature on this subject. As the effectiveness of current local anaesthesia techniques associated with exodontia under GA remain unproven, future similarly designed trails examining the efficacy of pre-operative LA administered by the techniques standard for exodontia in the awake child would be welcome.