Stereophotogrammetry of the perineum during vaginal delivery

Abstract

On the basis of these stereophotogrammetry data, a technique of perineal protection executed by fingers of the posterior (right) hand can be proposed. Further experimental and clinical studies are needed to evaluate whether this technique might assist in reducing obstetric perineal trauma.

Manual perineal protection: The know‐how and the know‐why

“…Based on stereo‐photogrammetric analysis of perineal deformation during fetal head expulsion, MPP seems to produce its protective effect via dispersion of the highest perineal tension over a wider surface area. This is mainly achieved by a reduction in the transverse perineal tension using the accoucheur’s thumb and index finger alongside the vaginal opening . Subsequent computational biomechanical studies showed that such maneuver can produce up to a 30% reduction in relative tension in the perineal region, dependent on the precision of its execution .…”

“…Indeed, the maneuver is most effective when the thumb and index finger were applied 12 cm apart, 2 cm anterior to the posterior fourchette and approximated medially by 1 cm on either side. Another proposed mechanism by which MPP works is by facilitating the delivery of the fetal head with the least possible diameter . When the fetal head is crowning, the sub‐occiput is at the lower margin of symphysis pubis while the bregma is located posterior to the fourchette .…”

“…This is mainly achieved by a reduction in the transverse perineal tension using the accoucheur's thumb and index finger alongside the vaginal opening. [17][18][19] Subsequent computational biomechanical studies showed that such maneuver can produce up to a 30% reduction in relative tension in the perineal region, dependent on the precision of its execution. 18,20,21 Indeed, the maneuver is most effective when the thumb and index finger were applied 12 cm apart, 2 cm anterior to the posterior fourchette and approximated medially study took place in three maternity units that support manual perineal protection policy in three European countries (Czech Republic, Slovenia and the UK).…”

“…Another proposed mechanism by which MPP works is by facilitating the delivery of the fetal head with the least possible diameter. 17,22 When the fetal head is crowning, the sub-occiput is at the lower margin of symphysis pubis while the bregma is located posterior to the fourchette. 22 Hence, to enable the passage of the fetal head through the perineal structures with its smallest circumference, a final head extension has to occur either spontaneous or manually.…”

Evaluation of the angled Episcissors-60® episiotomy scissors in spontaneous vaginal deliveries

“…A 40° episiotomy (premarked with gentian violet staining) achieved an angle of 22° postdelivery, and a 60° premarked episiotomy achieved a postdelivery angle of 45°. Studies using stereophotogrammetry13 have described a perineal distension of 2.77-fold in the transverse plane and 1.43-fold in the vertical plane. This is similar to the perineal distension of 3.26-fold noted in magnetic resonance imaging studies 14…”