Skin cooling reduces pain associated with peripheral nerve block to the face

Peripheral nerve blocks are frequently used to treat chronic pain, but nerve block in itself may cause pain. Cooling the skin may inhibit pain associated with needle puncture to a venous, artery to the muscles, but it is not known if skin cooling inhibits pain associated with peripheral nerve block for chronic pain.

As a randomized crossover design, we studied 14 patients (after obtaining approval from the research ethics committee and written informed consent) in whom a supraorbital, infraorbital or jaw nerve block was indicated, to compare the degree of pain (assessed using the Numerical Rating Scale) during needle puncture and during injection of a local anesthetic (2 ml of 0.2% ropivacaine), with and without cooling of the skin (to 20 °C).

Pain was significantly less with skin cooling than without, during needle puncture (P = 0.002; 95%CI for median difference: 3-3), and during injection of a local anesthetic (P = 0.0036: 95%CI for median difference: 2-2). Injection of a local anesthetic was significantly more painful than needle puncture, both with skin cooling (P = 0.0039) and without skin cooling (P = 0.015). There was no significant difference in the effect of skin cooling in reducing pain between needle puncture and injection of a local anesthetic (P = 0.48).

In patients receiving peripheral nerve blocks to the face, cooling of the puncture site of the skin may effectively inhibit pain during needle puncture and during injection of a local anesthetic. Clinical trial registration jRCT1031230725.