To investigate the impact of cTBS on the incidence of postoperative delirium and changes of cognitive function in elderly patients after surgery. To explore whether short-term cTBS can reduce the risk of postoperative delirium as a preventive strategy.

Postoperative delirium is the most common postoperative complications among elderly. Nevertheless, there remains no effective medication or intervention been approved in postoperative delirium. Recent research suggests that continuous theta burst stimulation (cTBS) has shown positive effect on improving global cognitive function in multiple mental disorders. However, the effects on cognitive function in postoperative delirium remain uninvestigated.

Participants were included if they:

1. were 65 years old or older;
2. had orthopedic surgery under general anesthesia;
3. had normal cognitive function at enrolment [for illiterate, Mini-Mental State Examination (MMSE) ≥ 17; for individuals with 1-6 years of education, MMSE ≥ 20; for individuals with 7 or more years of education, MMSE ≥ 24];
4. were able to complete cognitive assessments and the Confusion Assessment Method (CAM);
5. Chinese Mandarin as their native language;
6. were willing to participate and being competent to provide informed consent.

Patients were excluded if they:

1. had delirium assessed by CAM before surgery;
2. had neurological diseases (e.g., stroke, Parkinson's disease, etc.) according to International Statistical Classification of Diseases and Related Health Problems 11th Revision (ICD-11);
3. had mental disorders (e.g., major depressive disorder, dementia, etc.) according to Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-5);
4. had contraindications of cTBS (e.g., head trauma, history of epilepsy or metal implants in the head);
5. participating in other clinical studies at the time of screening;
6. having postoperative complications such as pulmonary infection, pulmonary embolism and stroke.