Comparing cold-air analgesia, systemically administered analgesia and scalp nerve blocks for pain management during photodynamic therapy for actinic keratosis of the scalp presenting as field cancerization: a randomized controlled trial.

Background Photodynamic therapy (PDT) using methyl aminolaevulinate (MAL) is an effective treatment for extensive actinic keratosis (AK). However, pain is a major side-effect of this therapy. Objectives To investigate whether scalp nerve blocks (group 1) provide adequate pain relief during MAL-PDT of the scalp and forehead in 32 men with baldness. Methods The patients received intravenous (IV) analgesia [piritramide 7.5 mg IV, plus oral metamizole (40 drops 30 min prior to PDT)] in combination with cold-air analgesia (group 2; IV analgesia) and cold-air analgesia alone (group 3). Maximum pain was evaluated by means of a visual analogue scale (VAS) during and up to 300 min after PDT. Pain during PDT was further analysed according to a pain perception scale. Furthermore, we measured haemodynamics and investigated stress hormone levels in blood samples at different time points. Results Maximum pain during PDT (primary end point) was significantly reduced in the treatment group receiving scalp nerve blocks (VAS 2.1 +/- 1.3) compared with the treatment groups receiving IV analgesia (VAS 7.3 +/- 1.1) and cold-air analgesia (VAS 8.4 +/- 2.0; P < 0.05). No significant difference was found between groups 2 and 3 with regard to pain relief (P = 0.32). The increase in systolic blood pressure during the first 3 min of PDT was significantly lower for group 1 than for groups 2 and 3 (P < 0.001). No correlation between stress hormone levels and pain were found. Conclusions Scalp nerve blocks provide an effective method for pain management during PDT for patients with extensive AK.