Expert Commentary
Is it time to revive rotational forceps?
Contemporary data suggest that it is.
In today’s chess-learning environment, Ericsson notes, the computer plays a key role and can provide accurate feedback on each move the player executes. Computer chess programs have evolved to the point that they “are far superior in skill to any human chess player. Most important, computers can provide more accurate feedback on each chess move and are available at any time for practice,” writes Ericsson.
The same is true in sports. A tennis player does not practice by playing an endless series of games—though an ability to win a game is the ultimate goal. Rather, the athlete focuses on aspects of the game—the serve, for example—that can make the difference between winning or losing. Ericsson also notes that most musicians, dancers, and athletes “spend most of their time training by themselves to get ready to exhibit their skills for the first time in front of a large audience.”
These approaches are a better model for improving performance than the apprenticeship model, Ericsson argues. In medicine, one alternative might be the video recording of medical procedures in the clinic from multiple points of view—so that later viewers get both the “big picture” and a close-up view from the point of technical performance. After the recording is digitized and stored on a server, it can serve as valuable teaching for an unlimited number of residents.
Simulator training offers another venue for education, as it makes possible the isolation of difficult aspects of a procedure, which can then be repeated by the trainee as many times as necessary. In the future, it should be possible to link video recordings directly to simulators “so trainees could focus on particular aspects of the procedures and be required to respond to prompts with recordable actions,” Ericsson writes.
What this EVIDENCE means for practice
Given the extremely limited opportunities for observing forceps deliveries in the United States, it is time for us to explore new avenues for teaching other than the traditional apprenticeship model.
Is ultrasound evidence of levator muscle “avulsion” a real anatomic entity?
Dietz HP. Forceps: toward obsolescence or revival? Acta Obstet Gynecol Scand. 2015;94(4):347–351.
Da Silva AS, Digesu GA, Dell’Utri C, Fritsch H, Piffarotti P, Khullar V. Do ultrasound findings of levator ani “avulsion” correlate with anatomical findings? A multicenter cadaveric study [published online ahead of print May 15, 2015]. Neurourol Urodyn. doi:10.1002 /nau.22781.
Dietz takes a new tack in the debate over cesarean versus forceps by pointing to a recently highlighted abnormality in women who deliver by forceps: levator ani muscle avulsion, or LMA—traumatic disconnection of the levator ani from the pelvic sidewall. It has long been known that forceps deliveries can increase the risk of obstetric anal sphincter injuries (OASIS). Dietz contends that OASIS occurs at a rate as high as 40% to 60% after forceps delivery. He also notes, with some consternation, that the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine have advocated forceps as a way of reducing the high cesarean delivery rate.
When a parturient has been pushing for an extended period of time and there is a positional abnormality of the fetus, such as persistent occiput posterior position, cesarean delivery is often favored as a way of protecting the rectal sphincter. Dietz argues that cesarean delivery also protects against LMA, which “has only recently been recognized as a major etiological factor in pelvic floor dysfunction.” Dietz then presents a list of studies that have produced ultrasound findings of LMA in a high percentage of women undergoing forceps delivery—percentages on the order of 10% to 40%.
Enter Da Silva and colleagues, who argue that “the only true place to visualize the 3D structure of the human body, [and] thus validate imaging findings, [is] on cadaveric or live tissue dissections.” They undertook a cadaveric study to validate—or not—some of the findings of LMA summarized by Dietz.
Details of the study
The pubovisceral muscle (PVM) anatomy of 30 female cadavers was analyzed via 3D translabial ultrasonography to confirm LMA. The cadavers were then dissected to assess the finding anatomically. Da Silva and colleagues found LMA on imaging in 11 (36.7%) cadavers. LMA was unilateral in 10 (33.3%) cadavers and bilateral in 1 (3.3%). However, no LMA was found at dissection.
When an additional 39 cadavers were dissected, no LMA was identified.
On ultrasound, LMA is strongly associated with a narrower PVM insertion depth (mean of 4.79 mm vs 6.32 mm; P = .001). Da Silva and colleagues concluded that “there is a clear difference between anatomical and ultrasonographic findings. The imaged appearance of an ‘avulsion’ does not represent a true anatomical ‘avulsion’ as confirmed on dissection.”
