The Effect of Angle on the Position of the Catheter Tip in Paramedian Approach of Thoracic Epidural Catheterization

Ryu, Choon Gun; Ryu, Ho Geol; Lee, Chul Joong; Bahk, Jae Hyon

Abstract

BACKGROUND: Thoracic epidural analgesia is the mainstay of postoperative pain control after thoracotomy. Usually the epidural catheter is blindly inserted and secured without confirming the tip position. The purpose of this study was to determine the influence of epidural approach angle on the position of the thoracic epidural catheter tip.
METHODS
129 patients scheduled for thoracotomy were enrolled. Patients were randomized into two groups: narrow angle group and wide angle group. The epidural needle was inserted at the skin of T8-9 level in both groups. In the narrow angle group the epidural space was approached at T7-8, whereas in the wide angle group the epidural space was approached at T6-7. After epidural space confirmation, a B-D nylon multi-hole epidural catheter was threaded 8cm into the epidural space. The epidural catheter tip position was assessed using a small amount of radiocontrast dye under fluoroscopy.
RESULTS
The mean (95% confidence interval) position of the catheter tip was the mid-body of T5 (T5-6 - T5 upper body) in the narrow angle group and T3-4 (mid-body of T4-T3 lower body) in the wide angle group (P = 0.037).
CONCLUSIONS
When approaching the thoracic epidural space by a wide angle, we can place the epidural catheters at a higher level because of a straighter threading.