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Contents: Medical Education: Original Research

Six-Year Experience in Teaching Pelvic Floor Ultrasonography Using Pelvic Floor Phantoms

Jalalizadeh, Mehrsa MD; Alshiek, Jonia MD; Santoro, Giulio A. MD; Wieczorek, Andrzej Pawel MD; Shobeiri, S. Abbas MD, MBA

Author Information
doi: 10.1097/AOG.0000000000002729

Pelvic floor ultrasonography is gaining increasing popularity for evaluation of pelvic floor disorders,1–3 pelvic floor masses,4,5 endoanal pathology,6 mesh complications,7–9 and postpartum levator ani trauma (Van Delft K, Shobeiri SA, Sultan AH, Thakar R. Haematomas may masquerade as levator ani muscle defects [abstract]. Int Urogynecol J 2012;23:S237–8.).10–12 This endoluminal ultrasonography method is predominantly taught through practicing on a volunteer or patient. However, anal and vaginal introduction of ultrasound transducers by a novice ultrasonographer may cause discomfort in live human models.2 An attractive solution for both trainees and practitioners to gain crucial hands-on experience is to practice on simulated pelvic anatomy using pelvic floor phantoms.

Our phantoms are handmade structures designed to simulate pelvic anatomy for ultrasonography. We previously published an article describing how they were assembled and reported their interinvestigator reliability. Six three-dimensional ultrasonography expert physicians from urogynecology, radiology, urology, and radiology had an 89% interinvestigator agreement in identifying various structures in the phantom, indicating that pelvic floor phantoms can substitute for human models.13

The aim of this study was to assess trainees' diagnostic skills improvement using pelvic floor phantoms in our half-day workshops. We designed our workshops according to Objective Structured Assessment of Technical Skills, which is shown to be a reliable method to assess physician competency.14–19 We reported our 6 years of experience in teaching pelvic floor ultrasonography to international health care providers during half-day interactive Objective Structured Assessment of Technical Skills workshops. Preworkshop test scores were compared with postworkshop scores and improvement in diagnostic skills was analyzed.

Video 1.
Video 1.:
Scanning a phantom using an endoluminal 3- dimensional ultrasonography machine. This is a demonstration of using pelvic floor phantoms in teaching endoluminal 3- dimensional pelvic floor ultrasonography. The trainees are instructed to scan the phantom and find the anatomical and pathological landmarks as shown in the video. Video created by S Abbas Shobeiri and Mehrsa Jalalizadeh. Used with permission.

MATERIALS AND METHODS

Four ultrasound phantoms designed for endoluminal imaging (Fig. 1 and Video 1; Video 1 is available online at http://links.lww.com/AOG/B112) were used in our workshops sponsored by the American Urogynecologic Society, International Urogynecological Association, and the International Continence Society. Details of assembling such phantoms were previously published.13 The phantoms' design, construction, inception as well as the workshop structure and content were all conceived by the senior author (S.A.S.).

Fig. 1.
Fig. 1.:
A. The caudal view of the endoanal phantom. B. The cephalad view of the endoanal phantom. *Anterior; urethra; vagina; §posterior; ǁmesh; levator ani muscles. © Shobeiri. Used with permission.Jalalizadeh. Ultrasound Phantoms. Obstet Gynecol 2018.

The phantoms simulated the following:

  1. Endovaginal anterior compartment (Fig. 2);
  2. Endovaginal posterior compartment (Fig. 3);
  3. Endovaginal levator ani structures (Fig. 4); and
  4. Endoanal compartment (Fig. 5)

Fig. 2.
Fig. 2.:
A right sagittal view of the anterior compartment phantom including the bladder and the urethra in a phantom obtained with an endovaginal transducer. Yellow arrow indicates urethra. © Shobeiri. Used with permission.Jalalizadeh. Ultrasound Phantoms. Obstet Gynecol 2018.
Fig. 3.
Fig. 3.:
Demonstrates a right sagittal posterior view in a posterior compartment phantom obtained with an endovaginal transducer. © Shobeiri. Used with permission.Jalalizadeh. Ultrasound Phantoms. Obstet Gynecol 2018.
Fig. 4.
Fig. 4.:
Demonstrates an axial view of a lateral compartment phantom. Yellow arrow indicates urethra; blue arrow indicates probe in the phantom vagina; green arrows indicate levator ani defect; purple arrow indicates external anal sphincter. © Shobeiri. Used with permission.Jalalizadeh. Ultrasound Phantoms. Obstet Gynecol 2018.
Fig. 5.
Fig. 5.:
Demonstrates a right sagittal view in an anal phantom. Yellow arrow indicates internal anal sphincter; blue arrow indicates superficial transverse perinea muscle; green arrow indicates external anal sphincter muscle. © Shobeiri. Used with permission.Jalalizadeh. Ultrasound Phantoms. Obstet Gynecol 2018.

A BK Flex focus ultrasound machine and transducers were utilized for pelvic floor imaging. A BK 8838/48 linear transducer was utilized for three-dimensional endovaginal anterior and posterior compartment imaging. Resolution was 2/44 Hz, transducer frequency was 12 MHz, gain was 50%, and thermal and mechanical index were 0.1<4.0 and 0.57<180, respectively. The anterior compartment pelvic floor phantom could simulate views of the bladder, urethra, pubic bones, and an implanted sling (Fig. 2). The posterior compartment pelvic floor phantom provided three-dimensional endovaginal ultrasound views of the external anal sphincter, internal anal sphincter, rectovaginal septum, levator plate, and an implanted mesh (Fig. 3). Views of the puborectalis muscle, urethra, bladder, rectum, and an implanted mesh were simulated using the levator ani pelvic floor phantom (Fig. 4). The anal pelvic floor phantom provided views of the external anal sphincter, internal anal sphincter, rectovaginal septum, and levator muscles (Fig. 5).

Between 2009 and 2015, half-day instructional workshops were held annually at three different international meetings: International Continence Society, International Urogynecological Association, and American Urogynecological Society. The courses included a review of pelvic floor anatomy, basic ultrasound concepts and equipment, and identification of pelvic floor structures that could be found in the anterior and posterior compartments during endovaginal and endoanal ultrasonography. The first half of the workshops involved mainly didactic teaching. The second half of the workshops included hands-on ultrasound sessions. Four stations provided hands-on ultrasound experience, where participants followed a sequence of instructions to practice on a pelvic floor phantom using three-dimensional transducers. Each pelvic floor phantom session was 5 minutes long and the participants were expected to identify specific structures before proceeding to the next workstation. The structure of the course is shown in Figure 6. After the hands-on imaging, the participants reviewed various ultrasound case studies either in a small group setting or with a presenter. A preworkshop and postworkshop test was administered to the participants in a group setting in the auditorium provided by the conference organizers. They were not separated from each other, but they did not communicate. Forty questions were drawn from three-dimensional ultrasound images of anterior, posterior, levator ani, and endoanal compartments of normal human models and 20 more questions were drawn from patients with endoanal or endovaginal pathology. The endoanal pathologies were a prerectal abscess and a mesh. The endovaginal pathologies were a rectovaginal seroma, a mesh, and a sling.20 The structure of our workshop and contents of courses were kept consistent throughout the 6 years. The presenters were mostly kept consistent with a few exceptions depending on the presenter's availability in rotating workshop locations.

Fig. 6.
Fig. 6.:
Workshop course structure.Jalalizadeh. Ultrasound Phantoms. Obstet Gynecol 2018.

The study obtained exempt status from our institutional review board because it did not meet the requirement for inclusion of human participants. Only test results of participants who attended the whole phantom workshop were included in our analysis. Test results of participants who did not attend the entire workshop or those who practiced on anything other than our pelvic floor phantoms were excluded. Paired t test was used to compare preworkshop and postworkshop scores. McNemar test was used to compare before and after likelihood of correctly answering individual questions. A P value of <.05 was considered statistically significant for the overall test score analysis. McNemar test of individual questions was calculated using α=0.0008 as a result of multiplicity of tested hypotheses, increasing the overall confidence to (1−0.0008)60=0.95. The test was subcategorized into six categories: endovaginal imaging, endovaginal pathology, endoanal imaging, endoanal pathology, and anterior and posterior anatomy. Subcategory scores' improvement was analyzed using a paired t test. A P value of ≤.008 was considered statistically significant in the subcategory analysis. Data analysis was performed using Stata/IC 14.2.

RESULTS

Two hundred forty-three attendees were included in our analysis. One hundred eighty-four (76%) were women. The most common specialty was urogynecologists (154/243 [63%]). Twenty-six urologists (12%), 26 physical therapists (11%), 24 general obstetrics–gynecology surgeons (10%), nine radiologists (4%), and two anesthesiologists (1%) constitute the rest of participants. Mean age was 41.0 years (95% CI 39.7–42.2). Twenty-six percent of the participants had previous ultrasound training in levator ani muscle, 37% had endoanal ultrasound training, and 27% had urethral ultrasound training.

Attendees gave an average of 8.4 score to the course usefulness with 10 being the highest. The mode and median were 9 and 78% of participants gave a score of 8 or higher to the course. Mean participant preworkshop test score was 33.40 out of 60 (95% CI 31.80–35.00). Postworkshop mean score was increased to 51.35 (95% CI 49.82–52.88). Paired t test analysis revealed a statistically significant increase in mean total test scores (P<.001) after the workshop. Individual category analysis revealed a significant increase in average scores of all categories: endovaginal imaging, endovaginal pathology, endoanal imaging, endoanal pathology, and anterior and posterior anatomy (Table 1). Question-specific analysis is reflected in Table 2. McNemar analysis of individual questions revealed a significant postworkshop increase in the percentage of correct answers in 50 of the 60 questions (83%). Details of questions are provided in Box 1 and the pictures for the questions were previously published.20 The endoanal imaging and pathology had the most number of questions with statistically insignificant increase in correct answers (5/15 and 3/9, respectively).

Table 1.
Table 1.:
Mean and Median Increase in Overall Test Scores and in Subcategory Scores
Table 2.
Table 2.:
Question-Specific Score Improvement

Box 1.

Test Questions

  1. In this 3D volume picture, please circle which one is anterior. [B]
  2. In this 3D volume picture, please circle which one is cephalad. [C]
  3. In this 3D volume picture, please circle which one is the vagina. [B]
  4. In this 3D volume picture, please circle which one is the superficial transverse perinei muscle. [A]
  5. Which scanner probe was used to obtain these images? [A]
  6. In this 3D volume picture, please circle which one is the puboperinealis muscle. [C]
  7. In this 3D volume picture, please circle which one is the puboanalis muscle. [C]
  8. In this 3D volume picture, please circle which one is the iliococcygeus muscle. [C]
  9. In this 3D volume picture, please circle which one is the iliococcygeus muscle. [B]
  10. The view demonstrated here is: [A]
  11. What probe is used to acquire this image? [C]
  12. In this 3D volume picture, where is anterior? [B]
  13. In this 3D volume picture, where is the pubic arch? [A]
  14. In this 3D volume picture, please circle which layer is trigone. [A]
  15. In this 3D volume picture, please circle which layer is the longitudinal and circular smooth muscle layer. [B]
  16. In this 3D volume picture, please circle which layer is the striated muscle layer (rhabdomyosphincter). [C]
  17. In this 3D volume picture, please circle which layer is the compressor urethra layer. [D]
  18. The view demonstrated here is: [B]
  19. What scanner probe is used to obtain this image? [A]
  20. In this 3D volume picture, please circle which one is the external anal sphincter. [B]
  21. In this 3D volume picture, please circle which one is the puborectalis muscle. [C]
  22. In this 3D volume picture, please circle where is the internal anal sphincter. [B]
  23. In this 3D volume picture, please circle where is the external anal sphincter? [A]
  24. In this 3D volume picture please Circle where is the anococcygeal ligament. [C]
  25. The view demonstrated here is: [A]
  26. In this 3D volume picture, please circle where is the perineal body. [D]
  27. In this 3D volume picture, please circle where is the anorectum. [C]
  28. In this 3D volume picture, please circle where is the vagina. [B]
  29. In this 3D volume picture, please circle where is the cephalad. [D]
  30. In this 3D volume picture, please circle where is the internal anal sphincter. [B]
  31. In this 3D volume picture, please circle where is the external anal sphincter. [A]
  32. In this 3D volume picture, please circle where is the puborectalis muscle. [D]
  33. In this 3D volume picture, please circle where is the rectovaginal fascia. [C]
  34. What probe is used to acquire this image? [C]
  35. The view demonstrated here is: [A]
  36. In this 3D volume picture, please identify where the vagina would be. [A]
  37. In this 3D volume picture, please identify the anorectum. [B]
  38. In this 3D volume picture, please identify the external anal sphincter muscle. [B]
  39. In this 3D volume picture, please identify the puborectalis muscle. [D]
  40. In this 3D volume picture, please identify the internal anal sphincter muscle. [C]
  41. What probe is used to acquire this image? [A]
  42. The view demonstrated here is: [C]
  43. In this 3D volume picture, please identify where the vagina would be. [A]
  44. In this 3D volume picture, please identify the anorectum. [B]
  45. In this 3D volume picture, please identify the “defect.” [C]
  46. The view demonstrated here is [A]
  47. In this 3D volume picture, please identify the anorectum. [C]
  48. In this 3D volume picture, please identify the external anal sphincter. [A]
  49. In this 3D volume picture, please identify the “defect.” [B]
  50. What probe is used to acquire this image? [A]
  51. The view demonstrated here is: [A]
  52. In this 3D volume picture, please identify the vagina. [C]
  53. In this 3D volume picture, please identify the anorectum. [D]
  54. In this 3D volume picture, please identify the urethra. [B]
  55. In this 3D volume picture, please identify the bladder. [A]
  56. In this 3D volume picture, please identify the posteriorly implanted pig tissue. [D]
  57. The view demonstrated here is: [C]
  58. In this 3D volume picture, please identify the vagina. [B]
  59. In this 3D volume picture, please identify the bladder. [A]
  60. In this 3D volume picture, please identify the posteriorly implanted pig tissue. [C]

No difference was found between the gynecologist and the other specialties (51.3 vs 49.6, P=.09). Urogynecologists similarly scored in a statistically insignificant manner (34.3 vs 31.2, P=.08). Subgroup analysis of urogynecologists revealed a significant increase in their test results after our workshop (mean increase: 18.5, 95% CI 17.1–20.0, P<.001). Urogynecologists had significantly better test scores after the workshop compared with general gynecologists and other specialties (95% CI 51.2–54.4 vs 45.7–51.8, P=.006). There were no statistically significant differences in preworkshop test results of participants who previously had training in urethral, endoanal, or levator ani ultrasonography.

DISCUSSION

The three-dimensional endoluminal ultrasound technology has rapidly evolved and is increasingly utilized by specialists who perform pelvic floor imaging.2,10 We recommend incorporating pelvic floor phantoms in residency programs to teach pelvic floor ultrasonography to obstetrics–gynecologic residents and especially those interested in urogynecology fellowship training. At INOVA Hospital, we have instituted the new American Institute of Ultrasound in Medicine guidelines for the resident teaching and the resident ultrasound modules are incorporated in the INOVA Center for Advanced Medical Simulation.21

Our course was taught repeatedly with the same structure over a long period of time, which allowed us to evaluate knowledge retention using a 60-question preworkshop and postworkshop test. Our workshop was effective in teaching three-dimensional ultrasound techniques to a large number of participants. The learners took both tests in a group setting in the auditorium provided by the conference organizers. There was no way to separate the learners from each other, but they did not communicate; therefore, we believe the test scores validly represent individual diagnostic skills. Comparison of participants' scores clearly shows improvement in diagnostic skills after the workshop. McNemar analysis of individual questions allows us to scrutinize our workshop on a nuanced subcategory level. Diagnostic skills did not increase in 8 of 24 questions in the endoanal category after our workshop; this informs us that teaching the endoanal category possibly needs improvement.

Possible alternatives to the use of pelvic floor phantoms are live models, fresh-frozen cadavers, and computer simulation. We used human models in a few workshops in which transport of the phantoms was not feasible or in one case, the airport security dug into the pelvic floor phantom gel and rendered it unusable. The workshops not using pelvic floor phantoms were excluded from analysis because of the limited number of participants and heterogeneity of the workshops. Although the use of a human model may have inherent limitations, including cost and the need for privacy while performing endovaginal and endoanal examinations, it is expected that participant diagnostic skills would increase similar to a pelvic floor phantom workshop. Fresh-frozen or minimally embalmed human cadavers do not have the echogenic characteristics of living tissue and they are not good substitutes to be used for ultrasound teaching. Computer software, on the other hand, may realistically simulate performing ultrasonography; in 2004, Heer et al22 created software to teach endovaginal ultrasonography using ultrasound records of real patients. They incorporated a sensor on a pelvic model to stimulate holding the transducer and the images shown on a computer monitor were based on the location of the sensor in the pelvic model. The trainees were medical students and were taught ultrasonography of the basic uterus and appendices. Complex structures of the pelvic floor were not taught in Heer et al's22 study and it is unclear how feasible and costly it would be to include them in the software. Our phantoms simulated important details of the pelvic floor while eliminating the need for privacy. Pelvic floor phantoms provided hands-on experience to novice trainees, allowing them to focus their entire attention on operating the keyboard and orienting the transducer by eliminating the trainees' hesitation of hurting the patient or making mistakes.

As a limitation to our study and a possible focus of our future workshops, we could study the effects of varying our intervention arrangements; ie, didactics, followed by pelvic floor phantom practice compared with providing self-practice with the pelvic floor phantoms outside the workshops. Another limitation to our study is the inability to calculate the effect of preworkshop testing on participants’ diagnostic skills improvement. Indeed, in our workshops, the learners were prompted to use the pretest questions as learning points and these learning points were reinforced throughout the course of the workshops. One robust study design to eliminate these biases is the Solomon Four-Group study design; however, in a workshop setting, it was not possible.

As pelvic floor specialists, the learners have used abdominal probes to perform abdominal or perineal ultrasonography at some point in their careers. Because this study focused on endoluminal imaging, we believe that our study group was predominantly naïve to the workshop material. The pelvic floor phantoms created for this study were prototypes simulating some of the important structures in each compartment. Improvement in the quality of phantoms is an ongoing process. Further investigation is in progress to create more realistic and more detailed pelvic floor phantoms.

In summary, a structured pelvic floor ultrasound workshop utilizing pelvic floor phantoms increased participants' diagnostic skills in the setting of various national and international congresses.

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