The Superiority of Contralateral Oblique View for Mid-thoracic Epidural Assess

When performing a fluoroscopic-guided thoracic epidural block (TEB), an 18-gauge Tuohy needle will be used for interlaminar epidural access. If the epidural space was accessed under fluoroscopic guidance and using the loss of resistance technique with air. All procedures will be performed with a paramedian approach under the true AP and lateral view at first, If the interlaminar space is not visible, the CLO view will be used. If the needle is deemed to be in the epidural space when the loss occurred, six fluoroscopic views will be obtained: true AP, CLO at 40 degrees, 50 degrees, 60 degrees, CLO measured, and lateral. The CLO measured angle will be determined by measuring the angle between the superior lamina and spinous process on the midsagittal plane on thoracic MRI or CT.