Saline Infusion Sonohysterography (SIS)

Author: Dr Monica Pahuja*

What is saline infusion sonohysterography (SIS)?

Saline infusion sonohysterography (SIS) is a variety of pelvic ultrasound where a small volume of saline is instilled into the uterine cavity to allow clearer visualisation of the endometrial lining.

The procedure is carried out with the patient in the lithotomy position with a speculum in the vagina to allow cannulation of the cervix with a small flexible plastic catheter (HyCoSy). On insertion of the catheter, the speculum is removed and, with the catheter in place, the transvaginal ultrasound probe is inserted.

What are the generally accepted indications for SIS?

SIS is a good test to assess the endometrium for those patients who

  •  have persistent endometrial thickening;
  • have a suspicion of polyps;
  • require assessment of postmenopausal endometrium;
  • are taking tamoxifen;
  • have possible Asherman’s syndrome.

What are the prerequisites for having a SIS done?

A negative pregnancy test for those appropriate patients.

What are the absolute contraindications for a SIS?

  • Pregnancy;
  • Concurrent pelvic inflammatory disease.

What are the relative contraindications for a SIS?

  •  Possible pelvic inflammatory disease or vaginal discharge. The referrer should take steps to exclude current pelvic infection before the procedure.
  • Menstruating. SIS is generally best carried out at day 5–9 of the patent’s cycle. This is when the endometrial stripe is at its thinnest.
  • Cervical stenosis (inability to introduce catheter into the uterine cavity).

What are the adverse effects of a SIS?

There is a very small risk of endometrial infection post procedure.

Are there alternative imaging tests, interventions or surgical procedures to a SIS?

Hysteroscopy and curettage may provide similar and/or complementary information to SIS. This may be combined with cervical dilatation if the cervical canal is very tight. The examination should be scheduled day 2–3 after the end of the last period.

*The author has no conflict of interest with this topic.

Page last modified on 31/8/2018.

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