Comparison of the postoperative analgesic efficacy of the ultrasound-guided erector spinae plane block and intrathecal morphine in patients undergoing total abdominal hysterectomy under general anesthesia: a randomized controlled trial

Abstract

Purpose: Total abdominal hysterectomy (TAH) is a common surgical procedure. Erector spinae plane block (ESPB) and intrathecal morphine (ITM) provide adequate postoperative (PO) analgesia. However, ITM side effects may limit its use. Researchers investigated the efficacy of bilateral ultrasound-guided ESPB on PO pain and analgesic consumption compared to ITM in the first 24 h following TAH under general anesthesia.

Methods: 120 patients premedicated with 3 mg intravenous granisetron were randomized into three equal groups: bilateral ultrasound-guided ESPB, ITM or control group. The primary outcome of this study was the time to first request for a rescue analgesic (tramadol).

Results: Compared to the control group, the ESPB and ITM groups showed higher time to first request for a rescue analgesic and lower total tramadol consumption 24 h following surgery (P < 0.001) with significant differences between the ESPB and ITM groups (P < 0.001). The ITM group showed lower pain scores and lower readings of both serum glucose and cortisol levels compared to the other two groups 24 h after surgery (P < 0.001). The ITM group also had higher incidences of nausea and pruritus 24 h after surgery (P < 0.001). The use of a single intrathecal injection of 0.3 mg morphine did not show any respiratory depression.

Conclusion: 0.3 mg intrathecal morphine was superior to erector spinae plane block for postoperative pain relief, 24 h after surgery, regarding attenuated stress response, lower pain scores at rest and on coughing and lower tramadol consumption. IRB: IRB 00006379//31-1-2022.

Trial registration number: ClinicalTrials.gov Identifier: NCT05218733.

Keywords: Analgesia; Erector spinae plane block; General anesthesia; Intrathecal morphine; Pain; Postoperative; Total abdominal hysterectomy; Ultrasound.

Fig. 1

US pictures demonstrating the direction of the needle and anatomical landmarks during ESPB. [(A) ESPB before injection, (B) ESPB after injection)] (ESM erector spinae muscle, ESPB erector spinae plane block, TP transverse process, US ultrasound)

Fig. 2

Flowchart of the study

Fig. 3

Hemodynamic variables changes, visual analog scale (VAS) scores and surgery-related stress response between study groups. A Heart rate changes, B mean arterial pressure changes, C VAS at rest, D VAS on coughing, E serum glucose levels, F serum cortisol levels (*significantly different group based on post hoc Bonferroni test following ANOVA test; times significantly different from T0 or H0 had the symbol “⌂” based on post hoc Dunnett test following RMANOVA test)

Fig. 4

Kaplan–Meier curve for rate of requiring rescue analgesia between the study groups. (*significant, homogenous groups had the same symbol “a,b,c” based on post hoc Bonferroni test)

Fig. 5

Richmond Agitation–Sedation Scale (RASS) between the study groups [*significantly different group based on post hoc Bonferroni test following Kruskal–Wallis test (●outlier reading)]