Appropriate length of epidural catheter in the epidural space for postoperative analgesia: evaluation by epidurography

Abstract

SummaryIn current practice, the length of epidural catheter that should be left in the epidural space is not standardised for effective postoperative analgesia. This prospective, randomised, double-blinded study aimed to determine the most appropriate length of epidural catheter that should be inserted into the epidural space for postoperative analgesia. We recruited 102 women and assigned them into three study groups (3, 5 and 7 cm insertion). An epidural catheter was inserted and epidurography was performed. Postoperatively, mean pain scores, motor and sensory levels, and any complications associated with the epidural catheter were recorded. No statistically significant difference for mean postoperative pain score was found at all study timings. Motor and sensory blockade was also statistically insignificant. Unilateral sensory analgesia developed in one patient in the 7 cm group and epidural catheter dislodgement was observed in four patients in the 3 cm group. In order to minimise catheter-related complications for postoperative analgesia, the most appropriate length that an epidural catheter should be left in the epidural space is 5 cm. Continuous epidural analgesia is considered one of the most effective techniques for postoperative analgesia [1]. The position of an epidural catheter and the distribution of local anaesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia. The incidence of failed or inadequate epidural analgesia has been reported as 4.2-6.3% in one study, because of suboptimal placement of the epidural catheter within the epidural space [2]. In our institution, regular audit of the acute pain service also showed that catheterrelated problems are one of the main reasons for failed or incomplete epidural analgesia.In current practice, controversy exists regarding the length of epidural catheter that should be left within the epidural space for successful pain management. Inserting a limited length of the epidural catheter, i.e. 3-4 cm, may result in an increased incidence of migration of the epidural catheter out of the epidural space. However, if a longer length of epidural catheter is left in the epidural space, this may increase the likelihood of a unilateral block or intravenous cannulation [3]. Clinical trials have shown that even if the epidural catheter was left 2-5 cm in the epidural space, this was found to provide satisfactory analgesia. However, one trial has shown that if more than 3 cm of the epidural catheter is left in the epidural space, this increases the risk of transforaminal escape [4].The length of the epidural catheter that should be left in the epidural space has not been standardised. The main aim of this study was to determine the most appropriate length of epidural catheter that should be inserted into the epidural space for postoperative analgesia. The secondary aim was to determine the complications associated with different lengths of epidural catheter.

A Randomised Controlled Trial on Analgesic Effect of Repeated Quadratus Lumborum Block Versus Continuous Epidural Analgesia Following Laparoscopic Nephrectomy

“…After ensuring skin asepsis and draping the area with sterile cover, an 18G Tuohy epidural needle was inserted in vertebral interspace T10-11 and catheter was advanced 5 cm length within the epidural space. 6 We observed vacuum epidural catheter aspiration and a test dose of 3 ml bupivacaine 0.25% with adrenaline 1:200,000 without any change in pulse rate or blood pressure to confirm the position of catheter within the epidural space.…”

Accidental knotting and subsequent removal of a catheter from the epidural space in an adult cow: a case report

“…Insertion depth into the epidural space is commonly perceived as a risk factor for knot formation [8][9][10][11][12][13][14][15][16][17]; however, evidence is anecdotal, based on an assumed correlation between insertion depth and knot development. Knots have been described in people with catheter insertion as little as 2-3 cm into the epidural space [18,19], and prospective human studies evaluating catheter insertion depth of between 2 and 7 cm did not identify an association between insertion depth and knotting [20,21].…”

Peri-operative management of the obese surgical patient 2015

“…To reduce epidural catheter migration, it is recommended that at least 5 cm catheter should be left in the epidural space 62.…”