Learning curve for detection of pelvic parts of ureters by transvaginal sonography: feasibility study

Abstract

CONTRIBUTIONWhat are the novel findings of this work? Sonographers and/or gynecologists who are familiar with gynecological transvaginal sonography (TVS) should be able to become proficient in identifying the pelvic parts of both ureters after 40-50 TVS examinations. What are the clinical implications of this work?Detection of ureters is a feasible part of the TVS workup of women attending a tertiary referral center clinic. In deep infiltrating endometriosis, identification of ureters and diagnosis of proximal hydroureter can be vital to the woman and in the planning of surgery to prevent hydronephrosis and silent loss of kidney. ABSTRACT Objective To investigate how many examinations it takes to be able to identify the pelvic parts of the ureters on transvaginal sonography (TVS).Methods This was a prospective study including consecutive women attending a gynecological outpatient clinic in a tertiary referral setting. Prior to commencement of the study, three trainees, with a focus on gynecological surgery and TVS but with no experience in identifying ureters, each observed an expert examiner performing 10 routine TVS examinations, including identification of both ureters. All were standardized gynecological TVS examinations, with visualization of the pelvic part of both ureters. Consecutive women were then examined, first by the expert, unobserved by the trainees, and then by one of the three trainees, in the presence of the expert. To ensure that identification of the pelvic parts of the ureters could be incorporated feasibly into routine gynecological TVS in a tertiary referral setting, a time limit of 150 s was set for successful identification of each ureter. A successful examination was defined by identifying both ureters within the time limit. The number of women examined by each trainee was determined by how quickly they achieved proficiency, which was evaluated using the learning curve cumulative summation (LC-CUSUM) score. ResultsBetween January 2017 and June 2017, a total of 140 women were recruited for the study, with 135 patients being included in the final analysis. The three trainees were able to identify the right ureter after a maximum of 48 (range, 34-48) TVS examinations, and the left ureter after a maximum of 47 (range, 27-47) TVS examinations. Conclusions Sonographers and/or gynecologists who are familiar with gynecological TVS should be able to become proficient in identifying both ureters after 40-50 TVS examinations. Detection of the ureters is a feasible part of the TVS workup of patients attending a clinic in a tertiary referral center.

Ureter Visualization With Transvaginal Ultrasound

“…It may not be appropriate to suggest that learning how to visualize the ureters is possible in a set number of examinations, as all individuals learn differently with various strengths and weaknesses. This idea is in contrast to a recently published feasibility study, 28 which concluded that around 40 to 50 TVUS examinations are necessary to be capable of identifying the ureters with TVUS. We advocate for a competency‐based educational model rather than a “one‐size‐fits‐all” approach.…”

“…Our time limit to identify the ureters was 120 seconds compared to 150 seconds. This should have little bearing, as each of the participants in the study by Aas-Eng et al 28 identified bilateral ureters in less than 30 seconds in each case, with a median time to identify ureters ranging from 4 to 20 seconds. This was also consistent with a study by Pateman et al 13 that reported bilateral ureter identification in a median of 8 to 9 seconds.…”

“…There are key features that distinguish our study from the study by Aas‐Eng et al 28 First, our study participants were trainees (enrolled in an MIG surgery fellowship) with variable and generally limited experience with US, whereas the participants in the study by Aas‐Eng et al 28 were 12‐months out of their training, and each had performed approximately 1000 TVUS examinations. Our time limit to identify the ureters was 120 seconds compared to 150 seconds.…”

“…However, the variation in baseline US experience in this study might improve the generalizability. Like other learning curve studies in gynecologic US, 25,28,32 our study had few participant numbers. This is a difficult limitation to overcome, given the nature and number of fellows that may be available for recruitment for a study at any particular point in time.…”

International survey finds majority of gynecologists are not aware of and do not utilize ultrasound techniques to diagnose and map endometriosis

“…Improvements in gynecological ultrasound training in residency programs is recommended. In curriculum planning, there are now a number of learning-curve studies for detecting DE using TVS to use as guidance [18][19][20] .…”