Exploring the effects of repeated transcranial magnetic stimulation (rTMS) during the perioperative period on the incidence of postoperative delirium, postoperative cognitive dysfunction, and chronic postoperative pain in elderly patients, as well as its possible mechanisms.

Patients are recruited one week prior to the trial commencement, during which they are informed about the experimental protocol and associated risks. After obtaining informed consent and signatures, they are enrolled as study participants.Patients who meet the trial criteria are randomly assigned in a 1:1 ratio to the control group (sham rTMS group) and the intervention group (rTMS group, with rTMS intervention applied in the PACU after surgery) in a double-blind manner (with rTMS intervention and postoperative follow-up conducted by different researchers).

Note: This trial includes three co-primary outcomes-postoperative delirium (POD), postoperative cognitive dysfunction (POCD), and chronic postoperative pain (CPSP). To account for the different nature and timelines of these outcomes, the study was designed to include two parallel patient cohorts under a unified protocol:

1. Elderly patients undergoing gastrointestinal surgery are enrolled primarily for the evaluation of POD, a short-term outcome assessed within 3 days postoperatively.
2. Elderly patients undergoing thoracic surgery are enrolled to evaluate POCD (at 1 month) and CPSP (at 3 months), which are longer-term outcomes.

These two patient cohorts are studied concurrently but analyzed separately according to outcome-specific follow-up timelines and sample size estimations. A total of 122 gastrointestinal surgery patients were enrolled and analyzed for POD. The maximum estimated sample size is for the POCD and CPSP cohort (n=230). Results will be reported in phases corresponding to the completion of each outcome assessment.

Inclusion Criteria:

• Age ≥ 60 years;
• ASA ≤ 3;
• Elective surgery patients.

Exclusion Criteria:

• Refusal to sign the consent form;
• Mini-Mental State Examination (MMSE) score < 15;
• Preoperative neuropsychiatric diseases and history of neurological or psychiatric disorders;
• Preoperative cranial or scalp injuries;
• History of drug or alcohol abuse; Visual or auditory impairments, communication difficulties; Presence of metallic implants in the body; Preoperative history of severe cardiovascular disease or severe liver or kidney dysfunction.