[Radiologic position control of epidural catheters (epidurography). An instrument of quality assurance for regional analgesia].

Abstract

Epidural analgesia is a very efficient method of postoperative pain management. Nevertheless, problems such as unilateral analgesia, sensory loss and inadequate pain relief are often difficult to handle. Radiologic evaluation of the position of the catheter and the spread of radiopaque dye (epidurography) is an important advance toward a solution of these problems. METHODS. The findings of 110 consecutive epidurographies from the acute pain service of the Department of Anaesthesiology of the University Hospital of Kiel, Germany, were analysed. Radiograms were obtained following the injection of 2 ml and an additional 8 ml of radiopaque dye (iopamidol) in the anterior-posterior and lateral plane. In addition, typical and instructive examples of epidurographies from the past 8 years are presented. RESULTS. In 99 of 110 patients the epidurography revealed a proper position of the catheter. Seven cases of partial displacement (e.g. paravertebral spread of radiopaque dye) and two cases of complete misplacement were documented. Allergic reactions or other side effects were not observed. The radiologic criteria for a proper epidural position of the catheter are discussed (Fig. 2a). Furthermore, examples of the following malpositions of epidural catheters are presented: intravascular misplacement (Fig. 2b), paravertebral misplacement (Fig. 2c), paravertebral escape of radiopaque dye (Fig. 2e) and correct distribution after the catheter had been withdrawn 2 cm (Fig. 2f), intrathecal misplacement (Fig. 2g), and simultaneous spread of dye in the subarachnoid and epidural space in a patient with preceding dural tap (Fig. 2h). In some cases unexpected reasons for problems in postoperative pain management were revealed by epidurography (e.g. disc prolapse, (Fig. 2d). CONCLUSION. In our view epidurography is a valuable way of improving the quality and safety of postoperative epidural analgesia. It is an important tool for decision-making in the event of clinical problems. The benefits for the patients have to be weighed against the radiation exposure.