Transvaginal ultrasound ovarian diathermy: sheep as an experimental model

An experimental study was performed in a university research center. Seventeen female sheep (15 Corriedale e 2 Suffolk) in reproductive age were submitted to transvaginal ovarian cauterization with a monopolar Valleylab Force 2 electrocautery. Macroscopic and microscopic lesions were assessed. Ovarian size were 1.31 cm2 ± 0,43 (Corriedale) and 3.41 cm2 ± 0,64 (Suffolk). From 30 ovaries from Corriedale sheep punctured, only 3 were cauterized, presenting macroscopic and typical microscopic lesion. In the Suffolk sheep group, only one ovary was cauterized. No lesion could be found in the needle path.This is the first experimental animal model described for ovarian cauterization needle guided by transvaginal ultrasound. The sheep does not seem to be the ideal animal model to study this technique. Another animal model, whose ovaries are better identified by transvaginal ultrasound should be sought for this technique, theoretically less invasive, before it could be offered safely to women with polycystic ovary syndrome.The polycystic ovarian syndrome (PCOS) is the endocrine-metabolic disorder that affects more women on reproductive age, with a prevalence of 5 to 10% [1]. This syndrome is characterized by anovulation, clinical or biochemical hyperandrogenism and ultrasound image showing several small ovarian follicles [2]. In addition, 60% of the patients are obese and several have insulin resistance [1].Clomiphene citrate (CC) is the recommended first-line treatment for ovulation induction in PCOS patients [3]. However, around 20% of PCOS women are resistant to CC, requiring the second-line intervention: exogenous gonadotropins or laparoscopic ovarian surgery [3].Ovulation induction with gonadotropins requires daily parenteral injections, intense monitoring of ovarian response, and is associated with increased occurrence of multiple pregnancy and ovarian hyperstimulation syndrome (OHSS) [4].Laparoscopic ovarian surgery alone is as effective as gonadotropins to induce ovul