Fig. 2

The technique of real-time ultrasound-guided thoracic epidural catheterization. A Patient positioned in the left-lateral decubitus position. Note the skin markings of the thoracic spinous processes (SP) and interspinous spaces (ISS) at the target thoracic level. B Paramedian sagittal oblique sonogram of the target intervertebral level showing the laminae and interlaminar spaces. C Paramedian, in-plane, real-time ultrasound-guided (USG) Tuohy needle insertion from the caudal end of the transducer and from the non-dependent side. D Paramedian sagittal oblique sonogram demonstrating the Tuohy needle (white arrowheads) insertion in-plane and with its tip located adjacent to the interlaminar space, (E) Eliciting loss-of-resistance (LOR) to injection of saline to locate the epidural space. Note how the hands of the operator support the Tuohy needle—LOR syringe assembly on the patients back, (F) Illustrating LOR to air to locate the epidural space. SP; indicates a spinous process, ISP; interspinous space, ESM; erector spinae muscle, LF; ligamentum flavum, _* represents the interlaminar space