SHP group

The complete formula for the SHP includes Angelica dahurica 1 g (g), Asarum 2 g, Pinellia 1.5 g, Corydalis 0.5 g, Euphorbia kansui 1 g, Brassica alba 2 g, Ephedra 0.6 g, Arisaema consanguineum 0.8 g, Atractylodes macrocephala 1 g, and musk 0.1 g. The herbs are processed into powder and mixed with fresh ginger juice to create the SHP ointment. The SHP and placebo are manufactured by the Pharmaceutical Preparation Department in the First Affiliated Hospital of Guangzhou University of Chinese Medicine to meet the requirements of the regulatory guidance issued by the China Food and Drug Administration.

The selected acupoints are Feishu (BL13), Dingchuan (EX B1), and Shenshu (BL23) on both sides, for a total of 6 acupoints. The locations of the acupoints are shown in Fig. 3 according to the World Health Organization Standard Acupuncture Locations.

Acupuncture points for both groups

Participants receive an SHP through the following procedure: (1) each participant is asked to expose their back. (2) Two grams of ointment are squeezed by operational assistants onto a circular medical-proof fabric, with each piece of SHP being 1 cm in diameter. (3) One piece of the SHP is attached to each acupoint by an acupuncturist in each centre. (4) Participants are then asked to wait in a room for 120 min, and nurses are required to carefully observe them. If a participant feels any unbearable pain or a burning sensation, the SHP is to be removed immediately by the nurses. The exact treatment duration for each participant is recorded on the case report form (CRF).