The purpose of this study is to demonstrate the molecular effect of desflurane on DNA by measuring the global DNA methylation level in patients under going lumbar spinal stenosis surgery under general anesthesia.

Forty patients scheduled for lumbar spinal surgery will include in the study. Peripheral venous blood samples will collect prior to the induction of anesthesia (T1) and after 120 minutes (T2). Anesthesia will maintaine with 40%-60% O2-air mixture and 6% desflurane. DNA will obtain from blood samples with the help of DNA isolation kit and global DNA methylation analysis will perform by ELISA method.

Inclusion Criteria:

1. Ability to understand and willingness to sign an informed consent form
2. Elective lumbar spinal surgery that will take at least 120 minutes,
3. American Society of Anesthesiologists (ASA) physical status I and II
4. Be between the ages of 18 and 65

Exclusion Criteria:

1. Patients with ASA physical status III or IV disease
2. Smoking or alcohol consumption
3. Chronic systemic disease (diabetes mellitus,chronic pulmonary disorders, chronic kidney and liver disorders
4. recently received radiation, chemotherapy
5. malignancy
6. blood transfusion in operation
7. use of antioxidant supplements
8. have received general anesthesia in the last three months
9. Patients with known occupational exposures (operating room personnel, chemical plant workers

Patients with physical status I and II of the American Society of Anesthesiologists (ASA), aged between 18-65 and scheduled for lumbar spinal surgery, which will take at least 120 minutes, will be included in the study

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