This is a prospective observational study designed to evaluate the effects of different anesthesia techniques on tissue oxygenation and postoperative recovery in patients undergoing lower abdominal surgery. A total of 180 patients will be enrolled and evenly allocated into four groups based on the anesthesia method used: general anesthesia, spinal anesthesia, epidural anesthesia, and combined general plus epidural anesthesia.

Near-infrared spectroscopy (NIRS) will be utilised to monitor tissue oxygenation at the thenar and plantar regions during the perioperative period. Vital signs, VAS scores(min 0-max 10 points), Quality of Recovery-40 (QoR-40) scores(min 40-max 200 points), and additional postoperative recovery parameters- including length of stay in the post-anesthesia care unit and hospital, surgical site infection, wound revision, and mortality- will be recorded and compared across the groups.

The primary hypothesis is that regional anesthesia techniques enchance tissue oxygenation and are associated with improved postoperative recovery outcomes compared to general anesthesia alone. The study was approved by the local ethics committee and will be conducted at a single tertiary-care center.

Inclusion Criteria:

• Adults aged 18-80 years
• Scheduled for elective lower abdominal surgery
• Eligible for general, spinal, epidural or combined anesthesia techniques
• Provided writen informed consent
• ASA physical status 1-3

Exclusion Criteria:

• Refusal to participate
• Emergency surgery
• Severe cardiovascular or respiratory instability
• Pre-existing severe cognitive impairment of communication barrier
• Peripheral vascular disease affecting NIRS readind
• Local infection or anatomical anomaly preventing regional anesthesia

Adult patients aged 18-80 undergoing elective lower abdominal surgeries under one of four anesthesia techniques (general, spinal, epidural, or combined general+epidural) at a single tertiary hospital. Patients with peripheral vascular disease, severe cardiopulmonary instability, or cognitive/communication limitations were excluded.