SIS Quickly Evaluates Abnormal Uterine Bleeding

OB/GYN News, Nov 1, 1999 by Guang-Shing Cheng

NEW YORK -- Saline infusion sonohysterography is a quick, easy, relatively painless, and cost-effective way to evaluate unexplained uterine bleeding, according to Dr. Steven R. Goldstein.

"It's easier than placing an IUD, but you use many of the same materials," Dr. Goldstein said at a meeting on ob.gyn. ultra-sound sponsored by the American Institute of Ultrasound in Medicine.

Many patients with unexplained uterine bleeding may undergo routine blind biopsy and dilation and curettage when all they need is hormonal treatment, said Dr. Goldstein, professor of ob.gyn. and director of gynecologic ultrasound at New York University Medical Center, New York.

Not only does saline infusion sonohysterography (SIS) provide a better look at the uterine cavity and endometrium, it allows triage for operative hysteroscopy and eliminates unnecessary diagnostic hysteroscopy. Routine blind Pipelle biopsy may be good for global problems of the endometrium, but an isolated lesion or even carcinoma can still be missed. This is where SIS becomes useful.

The primary advantage of SIS is that the fluid allows a contrast to show an outline of uterine anatomy that is helpful in diagnosis and operative management. When findings on transvaginal ultrasound are inconclusive, a little fluid can clarify the picture.

In a study based on an algorithm with SIS, 433 patients were first evaluated with regular transvaginal ultrasound Am. J. Ob.Gyn. 177[1]:102-08, 1997). If their endometrial thickness was less than 5 mm, they were diagnosed with abnormal uterine bleeding, and no further studies were done. Those who had an endometrium greater than 5 mm or poor visualization were then evaluated with SIS. Previous studies have consistently shown that an endometrial echo of less than 5 mm is associated with no pathology on biopsy.

Symmetrically thin endometrium of less than 3 mm (single layer, since anterior and posterior endometrium are now measured separately) indicated dysfunctional uterine bleeding. Only symmetrically thickened endometrium were given a biopsy with a Pipelle. Any patient who had asymmetric endometrium or polypoid lesions went to the operating room for direct visualization with hysteroscopy.

Of 433 patients, 65% were diagnosed with dysfunctional anovulatory bleeding by unenhanced transvaginal ultrasound alone. Of the 153 patients who had SIS, 61 had dysfunctional uterine bleeding, 58 had global thickening or polyps removed hysteroscopically, and 22 had submucous myomas. Ten patients had symmetrically thick endometrium and subsequently underwent Pipelle sampling; half had proliferation and half had hyperplasia. SIS was technically inadequate for two patients.

Overall, 65% of the diagnoses were arrived at using transvaginal ultrasound alone; 17% by ultrasound and SIS; 2% by ultrasound, SIS, and Pipelle sampling; and the remaining 16% by ultrasound, SIS, and D&C hysteroscopy.

He estimated the cost of doing a D&C hysteroscopy without any imaging studies to be about $4,000 in New York City. Using the SIS algorithm would have cost only $1,047, about the same cost of using a Pipelle without ultrasound for all patients. However, since 18% of the women did not have global endometrial processes on ultrasound, these women may have been potentially misdiagnosed if Pipelle alone were used.

"If you really want to know what's going on with the patient, this algorithm will help," Dr. Goldstein said.

Like any procedure, SIS should be used optimally "A single two-dimensional snapshot of a seemingly normal endometrium does not rule out pathology" he cautioned. Be sure to move the transducer from cornua to cornua and from lower segment to fundus in the coronal plane to mentally recreate a three-dimensional picture of the uterine anatomy Dr. Goldstein advised.

Addressing Concerns About SIS

Dr. Goldstein outlined some practical concerns related to SIS and offered advice on how to address them.

* When to Do It. As the endometrium proliferates in the course of the menstrual cycle, pseudopolyps or asymmetric thickening may become evident. Be sure to schedule the sonohysterogram at the tail end of the bleeding, when the endometrium is in its thinnest and most uniform state.

* Inability to Thread Catheter Into Cervix. Dr. Goldstein uses a ring forceps to hold his SIS catheter in one hand. He uses his other hand to change the position of the speculum, which will often change the angle the cervix makes with the fundus, to allow the catheter to pass. He uses a very fine toothed tenaculum to stabilize the cervix.

* Anesthesia. None is required. Dr. Goldstein has experienced only one case of a vasovagal response. "But if you occlude the cervix, you will cause pain," he said. Dr. Goldstein generally allows the fluid to leak a little from the cervix to prevent uncomfortable fluid overload.

* Infection. The risk of infection is no greater than that associated with traditional hysterosalpingography, so treat the patient undergoing SIS similarly Testing for gonorrhea and chlamydia depends on the patient population. Dr. Goldstein said that he does not routinely obtain cultures or prescribe prophylactic antibiotics, and none of his patients have experienced infectious complications from SIS.