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.