The Effect of Transversus Abdominis Plane Block Timing on Milliequivalents of Opioid Use and Immediate Postoperative Pain Scores in Patients Undergoing Minimally Invasive Hysterectomy: A Retrospective Cohort Study

Study Objective: To examine the effect of transversus abdominis plane (TAP) block timing (preoperative or postoperative) on postoperative opioid use (quantified via morphine milligram equivalents; MME) and pain scores in patients undergoing minimally invasive hysterectomy for benign indications. Design: Retrospective, single-institution cohort study Setting: Academic-affiliated community hospital Patients: A total of 2982 patients were included who underwent a minimally invasive total hysterectomy between January 2018 and December 2022, excluding patients with a malignancy diagnosis, concurrent urogynecological procedure, vaginal hysterectomy, supracervical hysterectomy, or those with baseline narcotic use (opioid use within the 3 months before surgery). Patients were separated into 3 groups: no TAP blocks (n = 1966, 65.9%), preoperative TAP blocks (854, 28.6%), and postoperative TAP blocks (162, 5.4%). Interventions: Summary statistics and mixed-effects regression methods were used for data analysis. Measurements and Main Results: There was a statistically significant lower mean use of opioids (MME 43.2 vs 53.9, p = .002) among patients who received a TAP block (either pre or postoperatively) than those who did not receive a block. However, when comparing preoperative vs postoperative patients with TAP block, there was no statistically significant difference in mean opioid use (MME 43.4 vs 42.1, p = .752). There were no differences in postoperative pain scores between patients with and without a TAP block, however, more opioids were required in patients who did not receive a TAP block to achieve the same pain scores as those who did receive a TAP block. There was a statistically significant shorter time to discharge for TAP versus patients without TAP block(median 5.5 vs 6.3 hours, p ≤ .001) as well as preoperative versus postoperative patients with TAP block (median 5.3 vs 6.2 hours, p = .001). Conclusion: While TAP block use at the time of minimally invasive hysterectomy reduced use of postoperative opioids, the timing of TAP block, either preoperatively or postoperatively, did not significantly affect opioid use. Preoperative compared with postoperative TAP block administration significantly shortened the time to discharge.