This trial aims to evaluate the efficacy and safety of transcutaneous auricular vagus nerve stimulation (taVNS) for moderate to severe chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). This study is a prospective, randomized, controlled trial. A total of 68 patients with CP/CPPS will be recruited. After baseline assessment, the patients will be randomized into taVNS group (n = 34) and sham-taVNS group (n = 34). The intervention of two group will last for 4 weeks with a 8-week follow-up period after the treatment. The National Institutes of Health chronic Prostatitis Symptom Score index (NIH-CPSI), International Prostate Symptom Score Scale (IPSS), European quality of Life-5 Dimensions Questionnaire (EQ-5D), self-rating anxiety Scale (SAS) and self-rating depression scale (SDS) will be assessed. The adverse events during the whole study will be recorded detailedly.

Inclusion Criteria:

• Consistent with the diagnostic criteria of CP/CPPS of EAU or CAU, the clinical manifestations were recurrent and persistent prostate pain accompanied by abnormal urination and psychiatric symptoms, without infection or other obvious pathological conditions. The pain symptoms were mainly manifested as pain in the surrounding tissues centered on the prostate, and pain, swelling or discomfort in the scrotum, testis, lower abdomen, perineum, lumbosacral area, and medial thigh. Abnormal urination was characterized by frequent urination, urgent urination, urination pain, urethral burning, residual urination or white discharge from the urethra at the end of urination or defecation in the morning. The neuropsychiatric symptoms included dizziness and tinnitus, insomnia and dreams, anxiety and depression, and even impotence, premature ejaculation, and spermatorrhea. Symptoms lasting more than 3 months in the last six months
• 18 ≤ Age ≤ 50 years old
• NIH-CPSI ≥15 (patients with moderate to severe CP/CPPS)
• Signed informed consent and voluntarily participated in the trial

Exclusion Criteria:

• Patients with other diseases that cause urinary symptoms were excluded: Such as benign prostatic hyperplasia, testicular and epididymal and spermatic cord diseases, overactive bladder, neurogenic bladder, interstitial cystitis, glandular cystitis, sexually transmitted diseases, bladder tumors such as carcinoma in situ, prostate cancer, urinary male reproductive system tuberculosis, anorectal diseases, lumbar diseases, central and peripheral neuropathy, etc
• Patients with severe diseases of the heart, liver, kidney, hematopoietic system and poor nutritional status
• Patients with severe mental and emotional disorders, who were unable to cooperate with the study
• Patients who have been treated with CP/CPPS regimen in the past 4 weeks

De-identified individual participant data (IPD) that underlie the results reported in this article and any future publications from this study will be shared. This includes, but is not limited to: demographic information, clinical assessments, scores from the National Institutes of Health Chronic Prostatitis Symptom Score Index (NIH-CPSI), the International Prostate Symptom Score Scale (IPSS), the European Quality of Life Five-Dimensions Questionnaire (EQ-5D-5L), the Self-rating Anxiety Scale (SAS), and the Self-rating Depression Scale (SDS).

IPD will be available starting 6 months after publication of the primary results and will remain accessible for at least 5 years.

De-identified data will be made available to qualified researchers upon reasonable request. Researchers must submit a methodologically sound research proposal to the corresponding author at jiani_wu@aliyun.com. Access to the data will be granted after the requester signs a formal data access agreement.