A comparison of two different methods used in routine anesthesia practices will be made for the insertion of a catheter that will be placed at the waist for anesthesia in obese patients who will undergo orthopedic surgery.

60 obese patients aged 40-80, ASA II-III, BMI>30, who are planned to undergo elective orthopedic lower extremity surgery by placing a combined spinal epidural catheter at Sakarya University Medical Faculty Education and Research Hospital will be included in the study.

General anesthesia or regional anesthesia techniques are routinely used in lower extremity surgery in our clinic. When placing a combined spinal epidural catheter, the entry site is determined by looking at anatomical landmarks or using ultrasound.

Patients will be divided into two different groups as Anatomical Marking or Ultrasound.

Patients in the Ultrasound group will be taken to the block room in our operating room before the operation and a location marking will be performed with Ultrasound in the block room.

Patients in the Anatomical Marking group will be brought to a sitting position in the operating room in the operating room and a location marking will be performed by hand examination.

After determining the needle entry site, patients in both groups will undergo the Combined spinal epidural catheter placement procedure, which is performed routinely under sterile conditions, and the success rate at the first attempt, total success rates, number of needle redirections, and complications during the procedure will be compared.

Inclusion Criteria:

• ASA II-III
• BMI>30
• Elective orthopedic lower extremity surgery
• Combined spinal epidural anesthesia (CSEA)

Exclusion Criteria:

• Patients with CSEA contraindication
• ASA IV-V
• Diagnosed with scoliosis
• Patients with anatomical disorders
• Patients who did not agree to participate in the study
• Patients for whom follow-up conditions could not be met