- This multicenter, randomized, controlled, single-blinded trial evaluated pain ratings and opioid use in 50 women assigned to superior hypogastric plexus block at the time of laparoscopic hysterectomy and 50 assigned to standard care
- There was no significant difference between groups on the primary outcome, the proportion of patients who reported an average pain score <4 within two hours postoperatively: 57% of the block group and 43% of the control group
- Results were similar when patients recorded their pain scores for six days after surgery
- Superior hypogastric plexus block did not significantly reduce recovery unit length of stay or postoperative opioid use
Superior hypogastric plexus block (SHPB), also called presacral nerve block, has shown benefits in three trials as an opioid-sparing method of reducing pain after hysterectomy. During a laparoscopic hysterectomy, the block is performed by depositing local anesthesia, usually bupivacaine, near the superior hypogastric plexus, which has been implicated in chronic pelvic pain. The maximum effect of bupivacaine can last seven to eight hours, so in theory, an SHPB administered at the start of a hysterectomy would be active throughout the procedure and into the immediate postoperative period.
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Nisse V. Clark, MD, MPH, surgeon in the Minimally Invasive Gynecologic Surgery Center at Massachusetts General Hospital, and colleagues recently conducted the first randomized trial of SHPB in laparoscopic hysterectomy. The block was not significantly better than standard care in reducing postoperative pain, as they report in Obstetrics & Gynecology.
The trial enrolled 100 patients at three academic hospitals between January 2018 and February 2019. Fifty patients were randomized to standard care and 50 to an SHPB (10 mL of 0.25% bupivacaine injected after laparoscopic access). All patients received standardized preoperative medications and incisional bupivacaine. The patients and nursing staff were blinded to treatment assignment.
The primary study outcome measure was the proportion of patients who reported an average pain score <4 (on a visual analog scale of 0–10) within two hours postoperatively. There was no significant difference between the two groups on this measure: 57% in the block group and 43% in the control group.
Similarly, within two hours postoperatively, the median pain score was 3.9 for the block group and 4.7 for the control group (P=0.45).
There were no significant differences between groups in:
- Total time in the postanesthesia care unit
- Total opioid prescribed in the postanesthesia care unit
- Average pain scores on postoperative days 1 through 6 (recorded in patient logs)
- Total opioid used in postoperative days 1 through 6
The most likely reason the findings differ from those of previous trials is that all patients received interventions to reduce postoperative pain. Laparoscopy itself is associated with less postoperative pain and less opioid use than open hysterectomy. In addition, all patients were enrolled in an ERAS (enhanced recovery after surgery) protocol.
Other potential explanations:
- The bupivacaine dose was insufficient to reduce postoperative pain
- The timing of the block was insufficient to reduce pain within two hours postoperatively
- An SHPB block targets only midline visceral pelvic pain and not somatic pain, such as nociceptive pain receptors in the skin, deep tissue and muscles of the abdominal wall
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