The standard method for direct visualization of the uterine cavity is office hysteroscopy. It has a high success rate and is well tolerated. In a meta-analysis, the accuracy of diagnostic saline infusion sonography (SIS) was equal to that of diagnostic hysteroscopy. Some investigators reported that SIS causes less pain than office hysteroscopy.
This randomized unblinded controlled trial compares patient discomfort during SIS with that of vaginoscopic office hysteroscopy in an outpatient clinic. A total of 100 women with an indication for further investigation of the uterine cavity were randomized to either SIS or hysteroscopy. Pain was assessed independently by the investigator, and the patient using the visual analogue scale (VAS) and the present pain intensity (PPI) scale. The VAS rates pain as no pain if 0, and unbearable pain if 10, with >7 the cut off point for severe pain. With the PPI scale, no pain is scored as 0 and excruciating pain as 5, with >2 indicating severe pain. Success rate was defined as adequate inspection of the cervical canal and uterine cavity.
Compared with office hysteroscopy, the patient’s pain scores on both the VAS and the PPI were lower for SIS (P ≤ .01). However, there was no statistically significant difference between the two procedures in severe pain (VAS >7 or PPI >2). Multiple linear regression analysis showed that, in addition to SIS, factors associated with a statistically significant reduction in pain scores were multiparity, a shorter procedure time, and position of the fetus in anteversion. There was no significant difference in the success rate (94% for SIS versus 92% for office hysteroscopy).
This is the first randomized comparison of SIS and vaginoscopic office hysteroscopy. These findings confirm that both SIS and office hysteroscopy are successful well-tolerated procedures. Because SIS produces significantly less discomfort, the authors consider it the method of choice.