Comparative Analysis of the Postoperative Analgesic Effects of Caudal Epidural Injection of Ropivacaine Combined With Fentanyl Versus Ropivacaine Alone in Lumbosacral Spine Surgeries: A Randomized Double-Blinded Study.

Introduction: A single injection of local anesthetic as a caudal epidural block provides pain relief for 2-4 hours. This duration can be extended by adding adjuvants such as opioids (morphine, fentanyl, buprenorphine, tramadol), ketamine, α2 agonists (dexmedetomidine, clonidine), and adrenaline. Caudal analgesia also reduces the need for intravenous opioids during and after surgery, which helps avoid the systemic side effects of opioids. Additionally, adjuncts such as opioids synergistically augment the analgesic properties of caudal epidural anesthetics without escalating motor block. Combining local anesthetics and opioids also reduces the dose-related adverse effects of each drug.  Materials and method: Fifty-six ASA (American Society of Anesthesiologists) grade I and II patients undergoing lumbosacral spine surgeries were randomized into two groups. The RF group (n=28) received a single caudal epidural injection of 20 ml of 0.2% ropivacaine with 50 micrograms of fentanyl, while the R group (n=28) received 20 ml of 0.2% ropivacaine alone. Postoperatively, patients were monitored for pain levels, heart rate (HR), non-invasive blood pressure (NIBP), mean arterial pressure (MAP), and visual analog scale (VAS) scores. The time until the first rescue analgesia request and the total amount of rescue analgesia administered were also recorded.

Results: The two groups were comparable in terms of age, weight, height, and body mass index (BMI). In the R group, the VAS score was at least 1.82 at 2 hours and at most 5.96 at 6 hours, then decreased to 2.25 at 24 hours. In the RF group, the VAS score was at least 1.68 at 2 hours and at most 5.87 at 4 hours, then decreased to 2.29 at 24 hours. In the RF group, the time until the first rescue pain relief was needed was significantly longer compared to the R group (in RF, the mean value was 7.30 hours, and in R, 6.68 hours, p <.0001).

Conclusions:  The study shows that adding 50 micrograms of fentanyl to 20 ml of 0.2% ropivacaine for ultrasound-guided caudal block in patients undergoing lumbosacral spine surgeries results in longer analgesia duration and reduced VAS scores over the postoperative 24 hours.