A randomized controlled trial on analgesic effect of repeated Quadratus Lumborum block versus continuous epidural analgesia following laparoscopic nephrectomy

Abstract

Background: Epidural analgesia as the effective pain management for abdominal surgery has side effects such as paresthesia, hypotension, hematomas, and impaired motoric of lower limbs. The quadratus lumborum block (QLB) has potential as an abdominal truncal block, however, its analgesic efficacy has never been compared to epidural analgesia on laparoscopic nephrectomy. This prospective randomized controlled study compared the effectiveness of QLB with the epidural analgesia technique in relieving postoperative pain following transperitoneal laparoscopic nephrectomy.

Methods: Sixty-two patients underwent laparoscopic donor nephrectomy and were randomized to receive QLB (n = 31) or continuous epidural (n = 31). The QLB group received bilateral QLB using 0.25% bupivacaine and the epidural group received 6 ml/h of 0.25% bupivacaine for intraoperative analgesia. As postoperative analgesia, the QLB group received repeated bilateral QLB with the same dose and the epidural group received 6 ml/h of 0.125% bupivacaine for 24 h after surgery completion. The primary outcome was the 24-h cumulative morphine requirement after surgery. The secondary outcome was the postoperative pain scores. Sensory block coverage, hemodynamic changes, Bromage score, postoperative nausea-vomiting (PONV), paresthesia, and duration of urinary catheter usage were recorded and analyzed.

Result: The 24-h cumulative morphine requirement and pain scores after surgery were comparable between the QLB and epidural groups. The coverage of QLB was extended from T9 to L2 and the continuous epidural block was extended from T8 to L3 dermatomes. The mean arterial pressure (MAP) measured at 24 h after surgery was lower in the epidural group (p = 0.001). Bromage score, incidence of PONV, and paresthesia were not significantly different between the two groups. Duration of urinary catheter usage was shorter (p < 0.001) in the QLB group.

Conclusion: The repeated QLB had a similar 24-h cumulative morphine requirement, comparable postoperative pain scores and sensory blockade, higher postoperative MAP, a similar degree of motoric block, no difference in the incidence of PONV and paresthesia, and shorter urinary catheter usage, compared to the continuous epidural analgesia following transperitoneal laparoscopic nephrectomy.

Trial registration: ClinicalTrial.gov NCT03520205 retrospectively registered on May 9th 2018.

Keywords: Epidural analgesia; Laparoscopic nephrectomy; Patient-controlled analgesia; Postoperative analgesia; Quadratus lumborum block.

Fig. 1

CONSORT flow diagram

Fig. 2

Cumulative morphine requirement of QLB versus continuous epidural analgesia. Median (95% CI) values of cumulative morphine requirement (mg) after anesthesia recovery at each time point are as follows: 2 h, 0 (0.34–1.05) vs 0 (0.28–1.10) (p = 0.857); 6 h, 2 (0.69–2.08) vs 2 (0.68–1.93) (p = 0.977); 12 h, 3 (1.11–2.74) vs 3 (0.97–2.49) (p = 0.764); 24 h, 3 (0.69–2.62) vs 4 (0.66–1.88) (p = 0.792). The p-values were analyzed using Mann-Whitney test, the horizontal lines indicate medians; boxes indicate interquartile range; whiskers indicate range

Fig. 3

Dermatomal effects of QLB and continuous epidural analgesia. The QLB and epidural group showed similar percentage of sensory blockade on level T12–L1 (97–100%), T10–T11 (84%), L2 (58–61% of patients). The QLB group showed percentage of sensory blockade on level T9 (3% vs 61.3%), T8 (0% vs 32.3%), L3 (0% vs 6.5%) less than epidural group patients. QLB, quadratus lumborum block

Fig. 4

Intraoperative hemodynamic profile of QLB versus continuous epidural analgesia. The horizontal lines indicate medians; boxes indicate interquartile range; whiskers indicate range. Median (95%CI) values of hemodynamic parameters at time points as follows: MAP: baseline 91 (87.34–95.76) to 90 (88.36–98.99) (p = 0.524); post-induction, 81 (75.76–85.15) to 71 (70.36–79.06) (p = 0.072); gas-insufflation 92 (86.84–97.48) to 88 (82.90–92.52) (p = 0.210); pfannenstiel incision 78 (75.60–84.47) to 75 (73.91–82.03) (p = 0.486); end of surgery 75 (72.48–81.32) to 71 (68.22–75.17) (p = 0.063); 24 h 83.33 (78.72–87.95) to 72.26 (67.69–76.83) (p = 0.001); HR: baseline 80 (77.67–85.30) to 88 (80.16–90.93) (p = 0.215); post-induction 76 (70.87–78.10) to 73 (70.00–80.45) (p = 0.816); gas-insufflation 80 (71.48–81.16) to 74 (72.27–79.80) (p = 0.855); pfannenstiel incision 81 (77.95–90.89) to 80 (76.75–84.73) (p = 0.447); end of surgery 90 (83.64–92.17) to 80 (75.14–88.02) (p = 0.049); 24 h, 82 (64–100) to 82 (72–92) (p = 0.991); CI: baseline 3.20 (3.06–3.74) to 2.90 (2.81–3.38) (p = 0.173); post-induction 2.70 (2.43–3.01) to 2.70 (2.59–3.11) (p = 0.499); gas-insufflation 2.80 (2.44–2.98) to 2.90 (2.73–3.41) (p = 0.095); pfannenstiel incision 2.90 (2.78–3.25) to 2.80 (2.70–3.18) (p = 0.669); end of surgery 3.20 (2.79–3.33) to 3.00 (2.75–3.37) (p = 0.987); 24 h 3.08 (2.67–3.49) to 2.63 (2.34–2.93) (p = 0.071). The p-values were analyzed using Mann-Whitney test, *p < 0.05 is significant. QL, quadratus lumborum; MAP, mean arterial pressure