In the EA + CBZ + placebo group, patients received oral carbamazepine (CBZ) at a dosage of 100 mg per tablet three times daily (TID) after meals for 4 consecutive weeks. In the sham EA + CBZ group, patients were administered oral CBZ at 200 mg per dose TID after meals for the same 4-week duration.

The primary acupoints selected were the affected side's Sibai (ST2), Xiaguan (ST7), and Dicang (ST4). Based on the affected nerve branch, additional acupoints were chosen: for the ophthalmic branch, Tongziliao (GB1); for the maxillary branch, Quanliao (SI18); and for the mandibular branch, Jiache (ST6). Distal acupoints included bilateral Hegu (LI4) and Waiguan (SJ5). Electroacupuncture was applied based on the affected nerve branch. For the ophthalmic branch, the local acupoints selected were Xiaguan + Tongziliao; for the maxillary branch, Xiaguan + Quanliao; and for the mandibular branch, Xiaguan + Jiache. The distal acupoints selected were Hegu + Waiguan. A sparse-dense wave, 2/100Hz, was used, with a treatment duration of 60 minutes. The intensity of the electrical current was adjusted according to the patient's tolerance. Acupuncture was administered 3 times per week (with 1-2-day intervals between sessions) for 4 consecutive weeks, totaling 12 sessions.

In this group, superficial needling (0.5-1 mm depth) was performed at non-meridian points located 1 cm lateral to: (1) primary local acupoints ST2 (Sibai), ST7 (Xiaguan), and ST4 (Dicang) on the affected side; (2) branch-specific supplementary points GB1 (Tongziliao) for ophthalmic branch involvement, SI18 (Quanliao) for maxillary branch involvement, and ST6 (Jiache) for mandibular branch involvement; and (3) bilateral distal points LI4 (Hegu) and TE5 (Waiguan). Local acupoint pairs (ST7 adjacent +GB1 adjacent or ST7 adjacent +SI18 adjacent or ST7 adjacent +ST6 adjacent) and distal pairs (LI4 adjacent +TE5 adjacent) were connected to a modified electroacupuncture device with severed output wires (preventing current flow while maintaining indicator function), followed by 60-minute needle retention after parameter adjustment. Acupuncture was administered 3 times per week (with 1-2-day intervals between sessions) for 4 consecutive weeks, totaling 12 sessions.

Daily records of carbamazepine (CBZ)/CBZ-placebo medication adherence, pain episode frequency, and adverse reactions in both groups will be maintained until the end of follow-up. The recorded data will be used for intergroup comparisons and intra-group comparisons to evaluate the degree of pain status changes between groups and within individuals.

This study will assess the degree of hepatocyte injury and glomerular filtration function. Additionally, the incidence of severe liver or kidney impairment will be evaluated.

After completing each scale, the raw total score (X) is obtained by summing all item scores. This raw score is then multiplied by 1.25, to derive the standardized score (Y). The SAS cut-off value for clinical significance is a standardized score of 50, with severity classifications as follows: 50-59 indicates mild anxiety, 60-69 moderate anxiety, and scores above 69 severe anxiety.

The raw scores from each subscale are summed to obtain the total raw score, which is then multiplied by 1.25 to calculate the standard score. For the SDS, the cutoff for depression is a standard score of 53, with scores of 53-62 indicating mild depression, 63-72 indicating moderate depression, and scores above 72 indicating severe depression.