Radiological analysis of the position of epidural catheters in the thoracic epidural space.

Abstract

Thoracic epidural catheterization is used widely for anesthesia and postoperative pain control in thoracic and abdominal surgery. Generally, an epidural catheter is inserted only 4–5 cm into the epidural space, as excessive catheter insertion causes complications like vascular injury and paresthesias [1]. Nevertheless, a catheter can often be inserted quite a distance as a consequence of the catheter becoming dislodged outside the epidural space with changes in the patient’s position. Most studies of the amount of epidural catheter insertion have focused on the lumbar level [2,3]. Therefore, we examined catheter advancement at the thoracic level. This study enrolled 72 mastectomy patients graded as American Society of Anesthesiologists class I or II and treated under general or epidural anesthesia. A thoracic epidural catheter was inserted for post-surgical pain control. Patients with coagulopathy, infection at the needle puncture site, a history of spine surgery, or scoliosis were excluded. The aims of the study were explained to the patients and the study was approved by the Institutional Review Board. In a sitting position, the patient’s neck was flexed as much as possible while the patient held the opposite knee with both hands, and the inferior tips of both scapulas were palpated to find the seventh thoracic spinous process. Then, an epidural puncture was made in the largest interspinous space out of T3–4, T4–5, or T5–6. Using a midline approach, with the bevel of a 17-gauge Tuohy needle facing cephalad, the needle was inserted and the epidural space was confirmed by the loss-ofresistance method using air. Then, a 19-gauge end-hole epidural catheter (Flextip Plus TM Epidural Catheter; Arrow International