Comparison of Pain After Uterine Artery Embolization UsingTris-Acryl Gelatin Microspheres Versus Polyvinyl Alcohol Particles

When compared in a uterine artery embolization(UAE) animal model, Embospheres (ES) (Biosphere Medical, Rockland, MA)were found to induce less uterine ischemia than polyvinyl alcohol (PVA)particles. Given this finding, we aimed to test the hypothesis that ESis associated with less pain after UAE than PVA in human patients. Weperformed retrospective analysis on data from 72 consecutive UAEpatients, collected from a prospectively acquired database.Patient-controlled analgesia (PCA) pump-delivered morphine sulfate (MS)dosages were compared between patients who received ES versus PVA.Subjective pain scores (SPS) were also compared between the two groups.Secondary outcome measures, including embolic volume and clinicaloutcome data, were also collected. Linear regression and t-teststatistical analyses were performed. Null hypotheses were rejected atthe p < 0.05 level. Mean follow-up period in the PVApopulation was 178 days (range 28–426), versus 96 days (range 24–197)in the ES population. The mean MS doses used by ES and PVA patientswere 37.2 (s.d. 23.5) versus 47.1 (s.d. 26.8), respectively. Thisdifference was not significant (p > 0.15).Utilizing a standard 0–10 pain scale, the mean peak SPS for the ES and PVA groups were 5.58 (s.d. 2.77) and 5.07 (s.d. 2.99), respectively.The difference was not significant. The mean amount of embolic materialused in each ES and PVA patient was 4.86 cc (s.d. 3.01) and 3.52 cc(s.d. 1.63), respectively. The difference revealed a strong trendtoward statistical significance (p = 0.05). There was one treatment failure in each group of patients. Within both patientsamples, no significant correlation was found when comparing the volumeof embolic used and subsequent MS dose. Despite a strong trend toward asignificantly higher volume of ES used per patient, there is nosubjective or objective difference in pain after UAE with ES whencompared to PVA.