This observational study aims to compare the effects of spinal and general anesthesia on perioperative systemic inflammatory response in patients undergoing percutaneous nephrolithotomy (PCNL). Systemic inflammatory indices derived from routine complete blood count parameters, including Systemic Immune-Inflammation Index (SII), Systemic Inflammation Response Index (SIRI), Aggregate Index of Systemic Inflammation (AISI), Neutrophil-to-Lymphocyte Ratio (NLR), and Red Cell Distribution Width (RDW), will be evaluated. Preoperative and postoperative laboratory values will be analyzed to determine whether the type of anesthesia influences systemic inflammatory markers and related clinical outcomes.

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status class I-III
• Patients aged 18 years and older

Exclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status class IV or V
• Patients younger than 18 years
• Active infection or diagnosis of sepsis
• Malignancy
• Chronic inflammatory diseases (e.g., rheumatoid arthritis, systemic lupus erythematosus)
• Use of immunosuppressive therapy
• Pregnancy

The study population consists of adult patients aged 18 years and older who undergo elective percutaneous nephrolithotomy (PCNL) surgery and meet the eligibility criteria. Patients classified as American Society of Anesthesiologists (ASA) physical status I-III are included. All participants receive either spinal or general anesthesia as part of routine clinical practice, and no additional intervention is performed for research purposes.