The study will include 80 patients aged 18-65 years who will undergo elective arthroscopic meniscal surgery.

Patients with bleeding disorders, cardiac disease, liver and/or renal failure, arrhythmia and electrolyte imbalance, cerebrovascular disease, and those who do not wish to participate in the study will be excluded.

Patients will be randomly assigned to two groups of 40 using a sealed envelope method; Group 1 (spinal anaesthesia administered), Group 2 (lumbar/sciatic block administered).

After obtaining informed consent from the patients, they will be taken to the operating theatre and a venous access will be established with an 18 G peripheral venous cannula. Once on the operating table, patients will be monitored and an ECG will be performed, and blood will be drawn to measure WBC, lymphocyte, neutrophil, urea, creatinine, and CRP values. Group 1 patients will receive 2 mg midazolam, 50 mcg fentanyl and spinal anaesthesia. Group 2 patients will receive 2 mg midazolam, 50 mcg fentanyl and lumbar/sciatic block.

An ECG will be performed on both groups 5 minutes after anaesthesia. Intraoperative heart rate, saturation, and blood pressure monitoring will be performed for both groups. An ECG will be performed on all patients at the end of the case. At the 6th postoperative hour, an ECG will be performed on both groups, blood samples will be taken for WBC, lymphocyte, neutrophil, urea, creatinine, and CRP values, and the first analgesia duration will be recorded.The results obtained will be statistically evaluated, and the study will be concluded. Recruiting.

The study was designed as a randomised controlled double-blind trial. Eighty patients aged 18-65 years with ASA I-II status who were scheduled for arthroscopic knee surgery were divided into two groups of 40 patients each using a sealed envelope method. Group 1 (n=40) received spinal anaesthesia, and Group 2 (n=40) received a lumbar/sciatic block. Patients under 18 years of age, over 65 years of age, those for whom regional anaesthesia is contraindicated, those with known cardiac disease, arrhythmia, electrolyte imbalance, liver and/or renal failure, and those who do not wish to participate in the study will be excluded. After obtaining informed consent from the patients, they will be taken to the operating theatre and a venous access will be established using an 18 G peripheral venous cannula. Patients undergoing surgery will undergo routine ASA monitoring (ECG, non-invasive arterial blood pressure, pulse oximetry). Group 1 patients will receive 2 mg midazolam and 50 mcg fentanyl, followed by spinal anaesthesia. The patient will be placed in a sitting position, and a spinal block will be administered by injecting 15 mg of 0.5% bupivacaine (Marcain® spinal heavy, 0.5%, 4 mL ampoule, AstraZeneca) through a 26 G spinal needle into the L3-4 intervertebral space. Sensory block will be assessed with a pinprick test, and the operation will commence once sensory block at the T10 level is achieved. Group 2 patients will receive 2 mg midazolam and 50 mcg fentanyl, and a lumbar/sciatic block will be performed under ultrasound guidance.A combined sciatic-lumbar nerve block with a total of 40 cc of 0.5% bupivacaine will be administered. The sciatic block will be performed first. For this, patients will be placed in the lateral decubitus 8 position, with the leg to be blocked on top, in the 'Sim's' position. Under ultrasound guidance, 20 cc of 0.5% bupivacaine will be injected with a 10 cm regional nerve block needle (B Braun, Melsungen, Germany) following negative aspiration. In the same position, the entry point for the lumbar block will be determined under ultrasound guidance, and 20 cc of 0.5% bupivacaine will be administered following a negative aspiration test. For surgical anaesthesia, both the sciatic and lumbar nerve distribution areas will be tested with the pinprick test to assess complete sensory block and complete motor block in the knee, ankle, and toes. Patients with adequate block quality (no need for sedoanalgesia during the operation) will be included in the study. In both groups, heart rate and mean arterial pressure will be recorded preoperatively (T1), after anaesthesia administration (T2), during surgery at 5 (T3), 15 (T4), and 30 (T5) minutes, and postoperatively (T6). ECG recordings will be obtained preoperatively, 5 minutes after anaesthesia administration, at the end of surgery, and 6 hours postoperatively. The duration of the first postoperative analgesia will be recorded for all patients. Haemogram and biochemical parameters will be assessed preoperatively, at the end of surgery, and 6 hours postoperatively.

Inclusion Criteria:

• 18-65 years patient
• ASA I-II status

Exclusion Criteria:

• Patients under the age of 18, over the age of 65
• Those for whom regional anaesthesia is contraindicated
• Those with known cardiac disease
• Arrhythmia
• Electrolyte imbalance,
• Liver and/or kidney failure.
• Those who do not wish to participate in the study.