An Analysis of Postoperative Epidural Analgesia Failure by Computed Tomography Epidurography

Abstract

In this prospective study involving 125 patients, we analyzed epidural analgesia failure after major abdominal surgery using computed tomography (CT) epidurographies to compare the incidence of dislodgement of epidural catheters and leakage of solution from the epidural space between two groups of patients: patients with successful or failed epidural analgesia. Our hypothesis was that the incidence of dislodgement and leakage should be low when epidural analgesia is successful. A thoracic epidural catheter was inserted before general anesthesia and secured by subcutaneous tunneling. Bupivacaine (0.25%) was administered during surgery followed by continuous epidural analgesia with 0.125% bupivacaine (10 mL/h) and morphine (0.25 mg/h) for 48 h. Failure was defined as a visual analog scale pain score at rest more than 30 mm and/or interruption of epidural analgesia before 48 h for any reason. When failure was not due to unintentionally withdrawn, kinked catheters or adverse events (n = 11), a CT scan with contrast injection was performed. Control CT scans were also performed in patients with adequate analgesia (i.e., the success group). The incidence of failure was 24.8% (n = 31). CT scans in the failure group (n = 20) showed seven patients with catheters outside the epidural space, nine with normal distribution, one with unilateral spread, and three with leakage of solution outside the epidural space. In the success group, CT scans (n = 19) showed 11 patients with normal distribution, five with unilateral spread, and three with leakage. We conclude that the major cause of epidural analgesia failure was dislodgment of the catheter. CT scans were mostly useful for detecting leakage of injectate, which may be the early phase of dislodgment.

Audit of motor weakness and premature catheter dislodgement after epidural analgesia in major abdominal surgery

“…While our rate of premature catheter dislodgement (14.5%) during Period One may seem high, comparable rates are reported by others [6,[17][18][19]. We considered this unacceptably high, as it hampered postoperative rehabilitation and was unpleasant for the patients if a new catheter placement became necessary.…”

“…Our intention in advancing the catheter insertion deeper was to establish a broader margin for outward catheter mobility during patient mobilization. One reason for premature catheter dislodgement is fluid leakage along the outside of the catheter into the muscles of the back or to the skin [19]. The fluid can accumulate under the adhesive dressing and loosen the tape fixation to the skin [20].…”

Insertion length and resistance during advancing of epidural catheter

“…Bends were noted on the removed catheters, suggesting that after being advanced a short distance into the epidural space, the catheters became coiled within the epidural space [12,15,16]. A catheter bends when the tip confronts the dura mater, blood vessels, connective tissue, and neural structures that may hinder its advancement [4]. The force applied on the outside of the catheter catheter to thread it through the needle is transmitted to its tip until it confronts the structures in the epidural space (Fig.…”

“…The improper spread of the local anesthetic due to variations in the epidural anatomy [1][2][3] and suboptimal positioning of the catheter within the epidural space [4,5] are reasons suggested for failure in epidural anesthesia. An optimal length, varying from 2 to 4 cm, has been suggested for epidural catheter insertion, but this length is associated with the risk of catheter dislodgement during fi xation to the skin and patient positioning [6][7][8][9].…”

Pain Management After Thoracic Surgery

“…In a prospective analysis of post-operative epidural failure by computed tomography epidurolography during which 4 cm of epidural catheter was left in the epidural space 25% of the epidurals failed. The major cause of epidural failure was dislodgement of the epidural catheter out of the epidural space [180]. Four centimetre of catheter is probably insufficient for thoracic epidurals that are to remain in situ for a few days, 5-6 cm may be more appropriate [181].…”