Hysterosalpingo‐foam sonography (HyFoSy): a new technique to visualize tubal patency

Abstract

Assessment of Fallopian-tube patency is an important part of routine infertility work-up, as tubal obstruction is estimated to play a role in 12–33% of infertile couples1, 2. Several tests are available for this purpose, including hysterosalpingography, laparoscopy and dye test, selective salpingography and hysterosalpingo-contrast sonography (HyCoSy). HyCoSy allows assessment of the outline of the uterine cavity and patency of the Fallopian tubes. It can be performed with standard transvaginal ultrasonography equipment. An echogenic medium is injected transcervically using a cannula or applicator. The accuracy of HyCoSy has been found to be comparable to that of hysterosalpingography3, 4. A commonly used echogenic medium is Echovist® (Bayer Schering Pharma AG, Berlin, Germany), a suspension of slowly soluble galactose microparticles in an aqueous solution5. No allergic-type reactions for Echovist have been reported so far, but galactose allergy is a well known contraindication. Adverse reactions other than pain (vasovagal reactions, nausea, vomiting, hyperventilation and sweating) have been recorded in 5% of cases6. The commercial availability of Echovist for gynecological use is currently limited in most countries. The use of air with saline has been suggested by others as a cheap and easy-to-use alternative to Echovist7. However, as air bubbles disappear directly after mixing air and saline by shaking, it is only possible to inject air and saline intermittently into the uterine cavity by tilting a syringe filled with air and saline in order to alternate which is injected. In 2007 a non- (embryo-) toxic gel (ExEm-gel® Gynaecologiq BV, Delft, The Netherlands), containing hydroxyethylcellulose and glycerol, was introduced as an intrauterine medium for sonohysterography as an alternative to saline. Gel instillation offers a more stable filling of the uterine cavity and the technique has been associated with minimal inconvenience for the patient8. This gel and its compounds have been tested extensively and safely used in medicine9-13. To date more than 10 000 gel-instillation procedures with ExEm-gel have been performed without any serious side-effects (personal communication with the manufacturer). When this gel is pushed rigorously through small openings in syringes or tubes, turbulence causes local pressure drops resulting in air dissolving in the solution, and yielding foam that is stable for several minutes. ExEm-gel (containing 88.25% purified water), however, is rather viscous for passing into the Fallopian tubes. Therefore 10 mL ExEm-gel was diluted with 10 mL purified water (to give a mixture containing 94.12% water) and mixed to create foam (Figure 1). The mixture at this ratio created foam that was sufficiently stable to show echogenicity for at least 5 min and sufficiently fluid to pass through patent tubes. The viscosity of this foam (270 cP) is comparable with that of Echovist (400 cP). Syringe with foam and cervical applicator for the hysterosalpingo-foam sonography technique. In the first 30 patients in whom hysterosalpingo-foam sonography (HyFoSy) was performed (Figure 2) the procedures were uneventful. Furthermore, four viable pregnancies have so far been diagnosed following the procedure. Patent Fallopian tubes, and even spillage into the abdominal cavity, were visible. The efficacy of the procedure will be analyzed systematically in a larger group of patients and reported in the near future. For evaluation of the uterine cavity we prefer to use undiluted ExEm-gel, as the echogenicity of the foam can mask intracavitary abnormalities. As the ingredients of this foam are identical to those of ExEm-gel we expect that allergy and complications will be equally rare. No cautions are needed with regard to pregnancy in the same menstrual cycle as the HyFoSy procedure. It can be expected that with the increasing use of hysteroscopic sterilization techniques, contrast sonography will play a more important role as a reference test for demonstrating adequate positioning of intratubal devices and/or tubal blocking. Ultrasound image during hysterosalpingo-foam sonography showing patency of both Fallopian tubes. We think that in HyFoSy we have found a clean, safe, non- (embryo-) toxic and less expensive alternative to HyCoSy that can be performed by a single operator in the office or ambulatory setting. M. H. Emanuel*, N. Exalto , * Department of Obstetrics and Gynaecology, Spaarne Hospital, Heemstede/Hoofddorp, The Netherlands, Department of Obstetrics and Gynaecology, Erasmus University Medical Centre, Rotterdam, The Netherlands