Operative Vaginal Delivery



Operative Vaginal Delivery


Eyal Krispin



Introduction


History

It is instructive, in view of the above-stated purpose of examining the current status of operative vaginal delivery (OVD), to briefly review the past. The use of forceps dates back some 400+ years, whereas the use of the vacuum extractor (VE) began only in the 1950s (although James Young Simpson, after whom Simpson forceps are named, experimented with a VE device in the mid-1800s36). Much has changed since the crude design of the original Chamberlen forceps four centuries ago.37 During the 1700s, Levret and Smellie contributed the pelvic curve,38 and Tarnier elucidated the principle of axis traction in the 1800s.39 Kielland, Barton, and Piper designed and “field tested” their special instruments in the 1900s.40 More subtle design changes, such as the pseudofenestrated blades developed by Luikart,1 and the divergent forceps proposed and used by Laufe also occurred in the last century.41

In the mid-1950s, Malmstrom invented a practical VE device, which included rigid steel cups of various sizes.42 In 1973, Kobayashi introduced a soft cup product made of silicone rubber.43 Subtle refinements in cup design and construction as well as vacuum-generating equipment took place over the next three decades. Importantly, the commercialization and marketing of VE devices vastly exceeded anything that ever characterized the development of a new forceps. It is interesting to consider whether business interests affected the reversal of the ratio of forceps to vacuum operations between 1980 and 2000 or whether this was based solely on scientific or clinical grounds. In 1980, the rate of forceps to VE procedures in the United States was 18 to 1.2 By 1990, it was 3 to 2; in 2000, it was 1 to 2; and by 2017, it was 1 to 5 and swings further to the VE side.3 In 1952, more than half of all the babies in the United States were delivered by forceps. By 2002, that proportion had fallen to 2.3%. Combining forceps and VE deliveries accounted for only 3.3% of all deliveries in 2013.3 The steady, even precipitous, decline in OVD paralleled an unprecedented increase in cesarean deliveries worldwide, but especially in the United States. However, it is naïve to attribute the former to the latter without examining the problem more closely.

In the first half of the twentieth century, cesarean delivery was dangerous for mothers because it was associated with a high rate of maternal mortality. Refinements in blood banking, anesthesia, antibiotic availability, and hospital-based childbirth all made possible a 1950 report4 of 1000 consecutive cesarean deliveries without a maternal death. By 1980,5 that number had grown to 10,000 consecutive cesarean deliveries with no maternal mortality. The focus of care shifted from maternal outcome to perinatal outcome, and difficult instrumental vaginal deliveries came under scrutiny. Even by 1950, cesarean delivery was an option that only minimally increased maternal risk, but reduced the neonatal risk associated with difficult vaginal delivery. In the 1970s and 1980s, the cesarean rate escalated by far more than could be accounted for by the small number of difficult vaginal deliveries. The threat of litigation began to influence capable, well-trained practitioners to consider their own risk, in addition to those of mother and baby, in choosing a route of delivery when it appeared that spontaneous delivery was not an option. Studies conducted in the last 10 to 15 years have called attention to adverse sequelae associated with OVD: pelvic floor damage,6 risk associated with vaginal breech delivery7 and vaginal birth after cesarean delivery,8 and infant birth trauma.9 The contribution of other factors, such as the use of regional anesthesia and the presence
of family members in the delivery room, to the declining frequency of OVD is difficult to evaluate. Pediatricians and neonatologists focus on only one of the two patients whose interests must be considered in selecting the route of delivery, so they may favor cesarean delivery to improve the outcome for the neonate. More recently, women themselves have requested elective repeat and even elective primary cesarean delivery. All of these factors, and more that have not been cited, account for the shrinking percentage of OVD currently performed. With so few OVD procedures performed routinely, this is insufficient to train residents and, later, to maintain practitioner proficiency.


Training

OVD is an endangered species. In the animal kingdom, the label of “endangered species” implies that, unless special measures are adopted, extinction may result. Metaphorically, OVD may become extinct if current statistical trends continue unabated. Proper training in OVD techniques during residency is necessary but not sufficient. Those techniques, once learned, must be practiced to maintain this vitally important skill. The purpose of this chapter is to present the current status of both forceps delivery and vacuum extraction as options intermediate between spontaneous vaginal and cesarean delivery. Recommendations regarding how to interdict the progression toward extinction of OVD will be made at the close of the chapter, but a return to the “halcyon days” (of even a decade ago) is unlikely.

The written word (this chapter, for example) can impact on an operator’s skill to only a limited degree. In his textbook on forceps,10 Dr Edward Dennen advised that the trainee be given a series of “painstaking lectures” on the subject of forceps delivery and then “drilled extensively” on the manikin. Then the intern is allowed to do an easy case under direct supervision. After that, the volume of work would increase according to the individual’s ability and interest. However, the problem now is that there is no volume of work. Residents in training perform few OVD procedures. After they graduate, most perform even fewer.11

Some opinion leaders in the field of obstetrics and gynecology12 have written that elective forceps are no longer considered an indication. Others defend the practice, some when conditions for outlet forceps are met, and others who sanction elective low forceps as well. The American College of Obstetricians and Gynecologists (ACOG) concludes that OVD remains an important part of modern obstetric care and, under appropriate circumstances, can be used to safely avoid cesarean delivery.13

It has been said that “experience is not a substitute for training; it serves only to increase confidence, not skill.”14 This is a thought-provoking criticism of an accreditation system that places undue emphasis on numbers of procedures of whatever type, rather than the quality of training in that procedure. Admittedly, the latter is harder to evaluate.

Some clinicians believe that experience with both forceps and VE should be provided to residents and, if clinical volume is adequate, it would be honest to say that forceps training is more difficult to provide. While forceps is hard to learn but easy to master, VE is easy to learn but hard to master and, thus, more centers tend to be proficient in the latter and abandon the first.




Technique


Forceps

This section can only serve as a springboard to provide both the resident and the young practitioner with the impetus to read more and practice more in an effort to develop and refine their clinical skills. Procedure-specific textbooks are available to enrich the knowledge of proper technique but, analogous to hitting a golf ball or playing the piano, there is no substitute for practice. A few points are suggested below to guide the beginner through narrow straits (pun intended) that have been encountered by all who claim to be experienced in OVD. To intrigue the reader with more than a modicum of experience, some of these points are not available in other sources.

As noted in the ACOG Technical Bulletin on OVD,18 the ART of forceps is an acronym that stands for application, rotation, and traction. Of these, application is the most important, as the inability to apply the forceps effectively sabotages the whole procedure. A decidedly worse circumstance is to place the forceps inaccurately and fail to recognize the error prior to either rotation or traction. Three of the previously referenced “pointers” pertain to application:



  • For a head that is at 60° left occiput anterior (Figure 45.2), as in the case scenario, the posterior, in this case left, blade of the forceps should be applied first. The fingers of the protecting
    (right) hand should extend beyond the toe of the blade and should assist in maintaining the cephalic curve of the blade in contact with the contour of the fetal skull. Once the blade has been inserted to the appropriate depth, pressure with the index and middle fingers of the right hand on top of the blade should direct it to a position slightly inferior to the posterior (left) lambdoid suture. The anterior (right) blade should be held obliquely, not vertically, with the handle in the right hand extending toward the left groin of the woman. The handle should then be lowered in contact with the woman’s left thigh as the thumb of the left hand advances the heel of the blade into the pelvis. Almost immediately, the right cephalic prominence of the fetal head will be encountered, and this feature of the fetal frontal bone will cause difficulty in rotating the blade into the anterior, right upper quadrant of the pelvis where it needs to be. The secret is to press the handle laterally and inferiorly with the right hand, thereby bringing the blade away from the forehead of the baby. Simultaneously, the index and middle fingers of the left hand positioned under the right blade should lift it into its final position just below the anterior (right) lambdoid suture. Prior to checking the application, asynclitism (if present) should be corrected using a sliding lock, a key feature of Luikart and Kielland forceps.

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Jun 19, 2022 | Posted by in OBSTETRICS | Comments Off on Operative Vaginal Delivery
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