Pre-emptive ultrasound-guided superior hypogastric plexus block in pelvic cancer surgeries: a randomized double-blinded study

Background Superior hypogastric plexus is a retroperitoneal plexus that receives visceral sensation from pelvic viscera. Superior hypogastric plexus block (SHPB) was used for chronic pelvic pain and recently studied for postoperative pain. We examined the safety and efficacy of preemptive anterior US-guided SHPB to reduce postoperative morphine consumption. Thirty-six patients undergoing pelvic cancer surgery were randomly divided into two equal groups; group S in which patients received anterior US-guided SHPB immediately after induction of general anesthesia and before skin incision using 20 ml bubivacaine 0.5%, group C control group in which 20 ml normal saline was given by the same technique. Patients of both groups received morphine via PCA postoperative and followed for 24 h. In both groups, we measured the total morphine consumption, VAS, vital signs, and side effects. Results Demographic data, duration, and type of surgery were comparable in both groups. Total 24 h morphine consumption in mg was significantly lower in group S (43.8 +/- 2) than in group C (54.83 +/- 2) with P value < 0.001. VAS was significantly lower in group S in all time intervals from 2 till 24 h postoperative. Side effects were minimal with no significant difference between both groups. Conclusion Preemptive US-guided SHPB is a relatively safe and effective method to reduce postoperative opioid demands after pelvic cancer surgeries.