Ureter Visualization With Transvaginal Ultrasound: A Learning Curve Study

J Ultrasound Med. 2020 May 30. doi: 10.1002/jum.15345. Online ahead of print.

Abstract

Objectives: To evaluate the learning curve of gynecologic surgical fellows (ie, in training) to properly identify the ureters in real time while simultaneously performing and interpreting transvaginal ultrasound (TVUS) examinations.

Methods: We performed a prospective study, which took place at 2 centers in Sydney, Australia, from December 2017 to December 2018. Three fellows (F1-F3), of varying prestudy ultrasound (US) experience, were recruited to participate. One hundred fifty predetermined examinations were planned. A TVUS examination was performed by the study reference standard (an expert in gynecologic US). Subsequently, the fellows performed a focused component to identify bilateral ureters, having been blinded to the patient's clinical history and reference standard findings. Immediate feedback and hands-on teaching were provided after each of the fellow's evaluations were complete. To evaluate the number of scans needed to gain competency, the cumulative summation test for the learning curve was used.

Results: A total of 150 examinations were performed on 145 patients. One patient had a single ureter, and 1 patient had US evidence of hydroureter. The cumulative summation test for the learning curve for bilateral ureter identification showed that F1 did not reach competency by 50 TVUS examinations, whereas F2 and F3 required 41 and 31 TVUS examinations to reach competency, respectively.

Conclusions: Contrary to other studies on the topic, this study suggests that although it is feasible for surgical fellows to learn TVUS identification of bilateral ureters, not all fellows can reach competency during a program based on a predefined number of scans. We advocate for an individualized, competency-based medical education model in learning US for identifying the ureters.

Keywords: endometriosis; learning curve; transvaginal ultrasound; ureter visualization; ureteral endometriosis; urinary tract endometriosis.