Evaluation of Drug Spread in Ultrasound-Guided Erector Spina Plane Block With Fluoroscopy

The study will be carried out between March 2021 and June 2021 in Istanbul University Istanbul Medical Faculty Pain Medicine Clinic. Patients who undergone erector spinae plane block for any indication over the age of 18 will be included in the study. All procedures will be performed in the operating room under standard monitorization (ECG, pulse oximetry, non-invasive blood pressure) and all patients will be in the prone position. The application area will be sterilized with povidone-iodine solution. Mild sedation will be achieved by using 1-2 mg of midazolam and 50-75 µg of fentanyl iv. The target area will be visualized by General Electrics (GE) Logiq e Ultrasound device using a 10-12 MHz linear probe or 1-4 MHz curvilinear probe. Transverse processes and erector spina muscles will be visualised at the target vertebral level. After local anesthesia (1-2 cc 2% lidocaine), a 20 gauge spinal needle will be inserted using the "in-plane technique". The needle will be advanced to the transverse process, after it's position is confirmed with hydrodissection, a solution of 40 mg triamcinolone, 10 ml 0,5% bupivacaine, 10 ml radiopaque contrast agent will be injected. Contrast spread will be evaluated with the fluoroscopy in the anterior-posterior and lateral positions immediately and 30 minutes after the procedure. The level of contrast radiating in the AP plane and passing through the paravertebral space and the epidural distance in the lateral plane will be noted. In addition, sensory examination with a pin prick test will be performed to determine the presence of dermatomal hypoalgesia and/or analgesia.