Key points
-
When the correct technique is applied, forceps and vacuum extractors have low rates
of complications.
-
For the fetus with signs of hypoxia in the expulsive phase, operative vaginal delivery
has the potential to reduce exposure to intrapartum factors that promote hypoxic-ischemic
encephalopathy.
-
Medium and/or rotational forceps are appropriate options in selected circumstances
and require skill and experience.
-
Even though forceps are more effective than vacuum extraction for operative vaginal
delivery, they are more associated with severe perineal lacerations.
-
Cephalohematoma is more likely to occur with increasing duration of vacuum extraction.
-
Flexible vacuum cups have higher failure rates, but lower incidences of trauma to
the newborn’s scalp.
Recommendations
-
Operative vaginal delivery is contraindicated if the fetal head is not engaged, delivery
presentation is unknown, or if the fetus has suspected or diagnosed bone demineralization
or bleeding disorders.
-
Ultrasound evaluation prior to instrumentation of labor is recommended when there
is doubt in the clinical assessment of delivery presentation.
-
Routine episiotomy is not recommended in operative vaginal delivery because of poor
healing and discomfort associated with mediolateral episiotomy, and the risk of injury
to the anal sphincter and rectum with midline episiotomy. When individually indicated,
it should be mediolateral and performed only after a successful traction test.
-
In the prolonged pelvic period of fetuses estimated to weigh more than 4,500 grams,
intrapartum cesarean section for prevention of shoulder dystocia is preferable to
low operative vaginal delivery or outlet delivery. Similarly, operative vaginal delivery
with the fetal head in the mid pelvis should be avoided in fetuses estimated to weigh
more than 4,000 grams, and intrapartum cesarean section is indicated. In these situations,
instrumental delivery should only be considered in the presence of experienced operators,
through individual assessment of fetal position and size, history of previous deliveries
and maternal habits.
-
The attempt to use forceps must be interrupted if there is no progression of the cephalic
pole after three tractions performed with correct grip by an experienced operator.
-
Vacuum extraction should be avoided before 32 weeks and caution should be exercised
between 32 and 36 weeks, as the lower safe limit for gestational age has not been
established yet.
-
Vacuum extraction should be stopped when there is no evidence of progressive descent
of the fetal head or when the cup detaches on three occasions.
-
Sequential use of vacuum extraction and forceps is associated with increased neonatal
complications and should not be routinely performed. After a failed vacuum extraction
attempt, the risks and benefits of a sequential attempt to use a forceps or cesarean
section should be evaluated.
-
Neonatologists must be informed about the technique used in operative vaginal delivery.
Background
Operative vaginal delivery is used to provide a safe birth via the vaginal route based
on maternal and fetal indications. Its greater benefits are the prevention of a cesarean
section and its associated morbidities, as well as neonatal complications arising
from intrapartum hypoxia.[1]
Although the forceps has been presented as the resource with the greatest potential
for saving lives in the history of medicine, its current replacement by cesarean section
is a result of the lack of preparation of the new generation of obstetricians, the
inability of professors to teach its practice and the growing medical judicialization
of obstetrics. The forceps instrument currently holds stigma and social prejudice
arising from maternal and neonatal trauma caused by misuse. Vacuum extractors are
more contemporary instruments, and although less effective than forceps, they are
easier to use and have advantages that have made them instruments of choice in several
countries.[2]
In recent decades, an increase in the rates of cesarean sections performed in the
second stage of labor has been observed with a concomitant reduction in operative
vaginal delivery. Difficult fetal extraction in cesarean section is an event associated
with failure or lack of attempt at operative vaginal delivery, potentially aggravating
maternal and neonatal morbidity. Therefore, the acquisition of skills and competences
related to the use of forceps and vacuum extractors has become essential in the current
process of training obstetricians.[3]
What are the main indications and contraindications for operative vaginal delivery?
What are the main indications and contraindications for operative vaginal delivery?
For the fetus with signs of hypoxia in the expulsive phase, operative vaginal delivery
has the potential to reduce exposure to intrapartum factors that promote hypoxic-ischemic
encephalopathy.[1] The main indications for operative vaginal delivery are signs of acute fetal hypoxia,
maternal exhaustion, prolonged expulsive period, umbilical cord prolapse with complete
cervical dilation, sudden death of the parturient, arrested labor, persistent asynclitism,
rotational dystocia, third-degree deflected cephalic presentation (face) with variety
of anterior chin position, resistance of the soft tissue, uterine inertia, poor abdominal
press. The aim of forceps (or vacuum) called prophylactic (relief) is to reduce the
effort and discomfort of the pelvic period. Operative delivery is useful in maternal
conditions or complications that contraindicate expulsive effort (cardiopathies, severe
respiratory diseases, stroke, aneurysm, esophageal varices, spinal cord trauma, myasthenia
gravis, proliferative retinopathy, neuromuscular pathologies, etc.), in preventing
the non-reassuring fetal status and in pelvic vaginal delivery when the head is stuck
after failure of the initial maneuvers.[4]
[5]
Because it causes less maternal trauma than the forceps, the vacuum extractor is an
excellent alternative for operative vaginal delivery, especially for outlet delivery.
Its indications are similar to those of the forceps. However, as the vacuum extractor
requires more time for fetal extraction, it should not be the preferred method in
emergency situations. The main advantages of vacuum extraction include a reduction
in application errors, greater ease of learning, the possibility of self-direction
and autorotation, less use of force on the fetal head, less need for analgesia and
episiotomy and the reduction of birth canal lacerations. Vacuum-extractors with flexible
cups cause less severe trauma to the fetal scalp than those with rigid cups, and should
be preferred in simple vaginal deliveries.[4]
[5]
Operative vaginal delivery is contraindicated if the fetal head is not engaged or
the delivery presentation is unknown. The following are absolute contraindications
to operative vaginal delivery: cephalopelvic disproportion, total or partial placenta
previa and anomalous presentations such as transverse, second-degree deflected cephalic
(forehead) and third-degree deflected cephalic (face) with a variety of posterior
chin positions. It is also relatively contraindicated if the fetus has suspected or
diagnosed bone demineralization (osteogenesis imperfecta) or bleeding disorders (hemophilia,
Von Willebrand disease, alloimmune thrombocytopenia). Operative vaginal delivery in
fetuses weighing more than 4,000 grams must be judicious when choosing either forceps
or the vacuum extractor. With regard to fetuses with an estimated weight of less than
2,000 grams, forceps are the safest instrument and can be used in fetuses as small
as 1,000 grams.[4]
[5]
In the prolonged pelvic period of fetuses estimated to weigh more than 4,500 grams,
intrapartum cesarean section to prevent shoulder dystocia is preferable to low operative
vaginal delivery or outlet delivery. Similarly, operative vaginal delivery with the
fetal head in the mid pelvis (De Lee station 0 and + 1) should be avoided in fetuses
weighing more than 4,000 grams, and intrapartum cesarean section is indicated. In
these situations, instrumental delivery should only be considered in the presence
of experienced operators, through individual assessment of fetal position and size,
history of previous deliveries and maternal habits.[6]
Vacuum extraction is not risk free (cerebral and retinal hemorrhage), and is also
contraindicated in prematurity (gestational age < 32 weeks). Between 32 and 36 weeks,
the vacuum extractor must be used with great caution, as the lower safety limit for
gestational age has not been established yet. As the fetal extraction time with the
vacuum extractor is prolonged, the instrument should also not be used if there are
signs of fetal hypoxia. Vacuum extractors are also not indicated for pelvic vaginal
delivery (breech baby) nor for face presentation, and should be replaced by forceps
in these situations. Contraindications to vacuum extraction, although relative, also
include: previous collection of blood or trauma to the fetal scalp, fetal death, anomalies
of the cephalic pole (anencephaly, hydrocephalus), macrosomia and negative test traction
in a previous attempt to use forceps.[5]
[7]
What are the main instruments currently recommended for operative vaginal delivery?
What are the main instruments currently recommended for operative vaginal delivery?
Forceps and vacuum extractors are the main instruments recommended for extracting
the fetus from the birth canal, performed by grasping and pulling the fetal cephalic
pole. The choice of instrument is related to the operator’s preference and experience,
and to maternal and fetal conditions.[8]
[9]
Forceps are instruments with two broad branches, each with four components: blade
(seizes the cephalic pole), shank (or pedicle; located between the handle and the
blade), joint and handle. The best known models nowadays are Simpson, Kielland, Piper
and Marelli.[9]
Although forceps are more effective than vacuum extractors, they are more associated
with severe perineal lacerations. Simpson’s forceps are the most widespread worldwide.
It features crossed branches, English (by fitting) fixed lock, handle with finger
grips and fins (finger support) and fenestrated blades. The cephalic (adapts to the
cephalic pole) and pelvic (adapts to the maternal pelvis) curvatures of the blades
are prominent, and this specificity is advantageous for the grip and traction of the
cephalic pole. It has three sizes, with shank lengths of 30, 33 and 35 cm.[4]
[5]
[9]
Kielland’s forceps have crossed branches, but the articulation is performed by sliding,
allowing the asymmetrical application of the blades in the vagina and the correction
of asynclitism. It is 39cm long, handles are smooth with fin and identification buttons
(knobs) on the front side. In the articulated instrument, the shanks are superimposed
with the right above the left. Blades are fenestrated with smooth and rounded edges,
and have very discreet cephalic and pelvic curvatures, which makes it an specific
instrument for wide rotations ([Figure 1]).[9]
Source: photographic record by the authors.
Figure 1. Simpson (upper) and Kielland (lower) forceps
The Piper’s forceps are specific instruments for extracting the head (breech baby)
in pelvic delivery. It has long (44cm long) crossed branches, English lock and handle
without finger grips and fins. Blades are fenestrated with very prominent cephalic
and pelvic curvatures. A third curvature, the perineal, is present on the underside
of the handles, close to the blades ([Figure 2]).[9]
Source: photographic record by the authors.
Figure 2. Piper’s forceps
Marelli’s forceps are specific for fetal extraction in cesarean sections. It has crossed
branches, English lock and smooth handle without fins. Its blades are fenestrated
without a pelvic curvature (“bayonet” shaped blade), since fetal extractions with
this instrument are performed through the abdomen ([Figure 3]).[5]
[9]
Source: photographic record by the authors.
Figure 3. Marelli’s forceps
Vacuum extractors are instruments that have a cup, a connecting tube and a suction
pump. By means of negative pressure, the cup, applied to the scalp, pulls the fetal
head. Cups can be rigid (made of metal), semi-rigid or flexible and have a bell or
mushroom shape ([Figure 4]). Flexible bell vacuum extractors have higher failure rates, but lower incidences
of trauma to the newborn’s scalp.[8]
Sources: photographic records by the authors; https://www.panamedical.com.br/vacuo-extratores.
Figure 4. Kiwi Omni Cup® (left), Mityvac® (center) and Mystic II (right) vacuum extractors
Spatulas and the Odon device are less widespread instruments. Spatulas are instruments
with two independent and symmetrical branches that do not articulate. Each branch
has a stem, handle and solid, wide blade. The branches act as independent levers and
the fetal head is not pinched between the blades. The action of the spatulas is similar
to that of the shoe presser, whose function is to help slide. Thierry, Velasco and
Teissier spatulas are described.[10] Velasco’s spatulas are smaller and straighter. Thierry’s spatulas are larger and
have a slight pelvic curvature at the upper edge of the blade ([Figure 5]). Compared to forceps and vacuum extractors, neonatal complication rates for spatulas
appear to be similar or lower. Rates of severe perineal lacerations are also similar,
but vaginal wall lacerations are more common.[11]
Source: photographic record by the authors.
Figure 5. Thierry’s spatulas
The Odon device is a film-type polyethylene instrument that creates an air envelope
around the fetal head, allowing extraction by means of traction ([Figure 6]).[12]
[13] It has the potential to be safer and easier to apply than forceps and vacuum extractors.
Currently, it is being used in multicenter experimental clinical trials, although
not yet cleared by regulatory agencies for clinical practice. In a pilot observational
study, the success rate at birth was close to 50% without severe maternal or neonatal
adverse outcomes, but lower than those of the other instruments.[14]
Source: Adapted from Odon Device (2020)[12] and Silvestri (2013)[13].
Figure 6. Odon device
How should operations in operative vaginal delivery be classified?
How should operations in operative vaginal delivery be classified?
Classifications of operations in operative vaginal delivery are based on pelvic planes
and delivery mechanisms. The application performed before the engagement of the cephalic
pole (“high forceps”) is contraindicated. The American College of Gynecology and Obstetrics
(2015), endorsed by the Royal College of Obstetricians and Gynecologists (2020) has
the most current classification ([Chart 1]).[4]
[5]
Chart 1.
American College of Gynecology and Obstetrics Classification of Operative Vaginal
Delivery (2015)[4]
|
Type
|
Findings
|
|
Outlet
|
The fetal scalp is visible at the vaginal introitus without separating the labia minora;
the fetal skull has reached the pelvic floor and is near or occupying the perineum;
the sagittal suture is in the antero-posterior (OA, OP) or oblique (LOA, ROA, LOP,
LOP) diameter, with rotation not exceeding 45°.
|
|
Low
|
Cephalic apex in the De Lee plane + 2 or below, without reaching the pelvic floor.
Two situations may occur:
a) Rotation ≤ 45° (LOA, ROA, LOP, ROP);
b) Rotation > 45° (include LOT and ROT).
|
|
Mid
|
The cephalic pole is engaged, but above De Lee’s plane + 2; rotation can be ≤ 45°
or > 45°.
|
OA: occiput anterior; OP: occiput posterior; LOA: left occiput anterior; ROA: right
occiput anterior; LOP: left occiput posterior; ODP: occipito-right-posterior; LOT:
left occiput transverse; ROT; right occiput transverse
What are the prerequisites for performing an operative vaginal delivery?
What are the prerequisites for performing an operative vaginal delivery?
The main prerequisites for operative vaginal delivery include information and agreement
on the benefits and risks of the procedure, adequate maternal pelvis, fetal weight
estimate performed (clinical or ultrasound), engagement of the cephalic pole, complete
cervical dilation and effacement, ruptured membranes, previous bladder emptying, knowledge
of the presentation and variety of position, and satisfactory anesthesia (regional
block in medium / rotational applications, pudendal or perineal blocks in low and
outlet applications).[15]
What are the main operative times and technical details of forceps application?
What are the main operative times and technical details of forceps application?
The application of the forceps must be preceded by a urinary catheter and satisfactory
maternal anesthesia. Low spinal anesthesia (“saddle”) is preferred, especially in
emergency situations and in mid and rotational forceps. It has the advantages of quick
installation, providing anesthetic blockade of the sacral fibers and perineal relaxation
without interfering in uterine contractility, abdominal press and quality of pushing.
In situations where the parturient is already under analgesia by epidural block, with
a catheter installed, the infusion of higher doses of anesthetics will be necessary
and the time for achieving satisfactory analgesia will be longer.[16]
The operative times are sequentially: presentation of the instrument in front of the
vulva, introduction and application, gripping of the cephalic pole, assessment of
grip, traction test and definitive traction (with or without rotation).[4]
[5]
The first stage involves presenting the instrument to the vulva, simulating the way
it will look after being applied to the fetal head ([Figure 7]). The grip includes the application (introduction and placement) and the actual
grip. In the case of forceps, to apply the branches, movements of “lower introduction”
are performed, always penetrating with the blades through the sacral voids (bilateral
spaces between the sacrum and the hamstrings). In oblique varieties, the posterior
branch must always be the first one to be applied. In transverse varieties (Kielland’s
forceps), the first branch to be inserted is optional, but the anterior branch is
usually preferred. In the direct varieties (occiput posterior [OP] and occiput anterior
[OA]), the left branch must be applied first in order to avoid the need to uncross
the branches after applying the second (right branch) ([Figures 8] and [9]). In the rotated cephalic pole, the branch that will be applied to the anterior
parietal is introduced through the triple spiral movement, which sequentially includes
translation, lowering and torsion of the handle (Lachapelle’s maneuver) ([Figure 10]). It is important to point out that manual rotation is an alternative for correcting
the rotated cephalic pole (transverse and oblique position varieties). The cephalic
pole is grasped with the tips of the fingers positioned on the parietal bones (thumb
on one side and the other fingers on the other). During uterine contraction, the fetal
head is slightly elevated, flexed and rotated, until it is positioned in a variety
of OP positions.[4]
[5]
Source: photographic record by the authors.
Figure 7. Simpson’s forceps presentation in the occiput posterior position
Source: photographic record by the authors.
Figure 8. Application of the left branch of Simpson’s forceps in the occiput posterior position
Source: photographic record by the authors.
Figure 9. Application of the right branch of Simpson’s forceps in the occiput posterior position
Source: photographic record by the authors.
Figure 10. Application of the right branch of Kielland’s forceps with the La Chapelle spiral,
in the left occiput anterior (LOA) position
The biparietal-mentonian is the ideal grip. Three fundamental diagnostic criteria
(Laufe’s criteria) are used to check the correct grip: the small fontanel must be
a transverse finger width from the plane of the handles (“in the center of the figure”);
the sagittal suture must be placed perpendicularly and equidistant from the plane
of the handles; the blade fenestrae should not be perceived by more than a finger
pad between the grasped head and the forceps on either side ([Figure 11]). After checking the ideal grip, the branches must be moved towards the occiput.[4]
[5]
Source: Illustration by Felipe Lage Starling (authorized).
Figure 11. Fundamental diagnostic criteria for ideal grip (Laufe)
The traction must be simultaneous to the contractions and performed axially, that
is, in the axis of the birth canal, perpendicularly to the presentation stop plane.
The operator should be seated at an adequate height with the chest at the same level
as the birth canal and the arms flexed just below the table. The force must be exerted
only with the arms. To obtain axial traction, the dominant hand positioned on the
handles exerts force directed at the operator’s chest. Simultaneously, the other hand
positioned on the rods applies downward force against the maternal perineum (Saxtorph-Pajot
maneuver) by providing a 45° vector and effective axial traction ([Figure 12]).[4]
[5]
Source: Illustration by Felipe Lage Starling (authorized).
Figure 12. Axial traction (Saxtorph-Pajot maneuver) in the occiput posterior position
Rotation is performed in the oblique and transverse varieties simultaneously with
traction. Rotation with Simpson’s forceps should be performed with a wide movement
of the handles in an arc (circumduction). With the Kielland’s forceps, the movement
of the handles is performed in a “key through the keyhole” movement and the rotation
can be completed before traction ([Figure 13]). Note that Simpson’s forceps are more suitable for small rotations. The Kielland’s
forceps should be the instrument of choice for rotations, especially when above 45°.
Once rotation is completed and successful traction is confirmed (positive traction
test), with the cephalic pole with the occiput below the pubic symphysis, the need
for episiotomy is assessed.[4]
[5]
Source: Illustration by Felipe Lage Starling (authorized).
Figure 13. Key through the keyhole rotation with Kielland’s forceps and wide circumduction movement
of the handles with Simpson’s forceps
The removal of forceps branches must precede the complete exit of the fetal head and
must be performed as soon as the mandible is accessible. The branches are removed
in reverse order of their application ([Figure 14]). Detachment of the cephalic pole is completed by the modified Ritgen maneuver.
After the fetal extraction and delivery are completed, the birth canal is revised
and if necessary, lacerations are repaired and/or episiorrhaphy is performed.[4]
[5] Despite the high effectiveness for resolution of the delivery, the attempt to use
forceps should be interrupted if there is no progression of the cephalic pole after
three tractions performed with correct grip by an experienced operator.[4]
[5]
Source: photographic record by the authors.
Figure 14. Removal of Simpson’s forceps branches in the occiput posterior position
What are the main operative times and technical details of applying the vacuum extractor?
What are the main operative times and technical details of applying the vacuum extractor?
Pudendal nerve block may be preferable to neuraxial anesthesia when choosing vacuum
extraction. Local anesthetic infiltration is performed bilaterally below the sciatic
spines. Unlike forceps blades, vacuum extractor cups do not come into significant
contact with the vaginal walls and do not increase the diameter of the cephalic pole.[5]
[15] The vacuum extractor must be tested by the operator immediately before use by creating
vacuum through compression of the cup on the palm of the hand. The instrument must
be presented in front of the vulva, demonstrating how the cup will be applied to the
fetal head.[17]
[18] The fetal scalp must be dried before the cup is applied. The cup will perform the
action of gripping the cephalic pole, and must be introduced in the vulvar vestibule
and applied over the sagittal suture, equidistant from the parietal bones with its
center 3cm in front of the lambda (at the point of flexion). With the center of the
cup positioned at the flexion point, its posterior edge will be 1cm (one finger) away
from the lambda ([Figure 15]). The cup must not be inadvertently applied over the fontanels. The positioning
of the cup is the same for any variety of position. In oblique position varieties
(left occiput anterior [LOA], left occiput posterior [LOP], right occiput anterior
[ROA], right occiput posterior [ROP]), the cup traction performed during the vacuum-extraction
process promotes the descent of the cephalic pole with autorotation.[17]
[18]
Source: Illustration by Felipe Lage Starling (authorized).
Figure 15. Fetal cephalic pole flexion point
A good grasp should be checked before traction, confirming the absence of maternal
tissue between the cup and the fetal head. The manometer should be calibrated to a
maximum of 500 mmHg (between 350 and 500 mmHg) during contractions with a reduction
to 100 mmHg during uterine relaxation.[17]
[18] However, maintaining pressure between 350 and 500 mmHg between contractions with
the aim to avoid discontinuing the descent and detachment of the cup does not seem
to increase neonatal complications and has also been recommended.[19]
The operator, seated in front of the delivery table with the chest at the level of
the birth canal, must pull perpendicularly to the cup plane until the occiput is positioned
below the pubic symphysis. Traction performed during uterine contraction should follow
the pelvic curvature (Pajot’s manuver), keeping the traction shank always straight
at a 90° angle with the cup. Thus, the pulling hand exerts a perpendicular force to
the planes of the cup and the fetal cephalic pole, towards the operator’s chest. Efficient
traction is obtained by the imbalance between the hand that pulls and the hand that
keeps the cup attached to the fetal cephalic pole, similar to a “tug of war”. This
force is opposite and slightly stronger than the force exerted by the hand that keeps
the cup attached to the fetal cephalic pole. The cup is kept attached to the fetal
cephalic pole by means of a force that is also perpendicular and exerted in a superior
direction, in the opposite direction to the traction force with a slightly weaker
intensity than this, sufficient to prevent the cup from detaching during the entire
action of traction. The superior steering force is exerted by the thumb positioned
in the center of the cup. Simultaneously, index and middle fingers are positioned
directly on the cephalic pole, thereby contributing to maintain the cup attached to
the fetal scalp ([Figures 16] and [17]). The manometer must be observed throughout the traction process in order to detect
the loss of vacuum, indicative of calibration correction.[17]
[18]
Larger red arrow: perpendicular pull force downwardsSmaller red arrow: perpendicular
force maintaining the cup at the fetal cephalic pole (thumb finger) upwardsDouble
red arrow: maintenance of the cup attached to the scalp (index and middle fingers)Black
letter J: direction resulting from the traction in the shape of a J (Pajot’s maneuver)Source:
Illustration by Felipe Lage Starling (authorized).
Figure 16. Vacuum extraction traction technique
Source: Photographic record by the authors.
Figure 17. Vacuum extraction traction technique
As soon as the occiput reaches the pubic symphysis, the suction pump and the connecting
tube of the vacuum extractor are elevated and the need for episiotomy is assessed.
After vulvar exteriorization of the fetal mandible, the cup is removed by pressing
the pressure relief valve (vacuum). The extraction of the fetal cephalic pole is completed
with the modified Ritgen maneuver.[17]
[18] Vacuum extraction is usually achieved with up to three pulls. Three additional gentle
pulls are acceptable to complete the cephalic pole deflection. The vacuum extraction
attempt should be stopped when there is no evidence of progressive descent of the
fetal head, when the cup detaches on three occasions or when the traction time exceeds
20 minutes. During traction, the sudden detachment of the cup by loss of vacuum and
vigorous movements must be avoided, as it leads to scalp lacerations. The sequential
use of the vacuum extractor and the forceps is associated with increased neonatal
complications and should not be routinely performed. Therefore, after a failed vacuum
extraction attempt, the risks and benefits of a sequential attempt at forceps or a
cesarean section must be carefully evaluated.[17]
[18]
What are the specific forceps techniques that require greater skill and competence
by the operator?
What are the specific forceps techniques that require greater skill and competence
by the operator?
Medium and/or rotational forceps are appropriate options in selected circumstances
and require operator skill and experience.[4]
[5]
[20] The posterior oblique and transverse position varieties and the head stuck (breech
baby) in pelvic delivery determine specific forceps application techniques.[9]
[20]
In forceps in posterior oblique varieties (ROP and LOP), there are three technical
options related to the model, forceps availability, and operator skill and preference.
Although rotation to OP requires more skill, it should be preferred whenever possible,
avoiding detachment of the cephalic pole in OA. In all application possibilities,
the posterior branch must be introduced first. Subsequently, the second (anterior)
branch is introduced through the Lachapelle’s maneuver.[9]
[20]
One option is to rotate 45° in the posterior direction for OA. In this situation,
the branches of the forceps are applied with the pelvic curvature of the blades in
an anterior direction. Although rotation is not wide, detachment of the cephalic pole
occurs in the posterior variety (OA), which requires more vigorous traction and indicates
Simpson’s forceps as the preferred instrument. The rotation must be performed in a
wide movement of circumduction of the handles.[9]
[20]
A second strategy for applications in posterior varieties, which has the advantage
of avoiding detachment of the occiput against the perineal musculature, is to perform
a wide 135° anterior rotation for the OP, followed by a single-grip extraction. This
technique requires operator experience and the use of a Kielland’s forceps. Here,
the slight pelvic curvature of this forceps allows the blades to be directed downwards
at the time of application. Once the 135° of rotation is completed (“key through the
keyhole”), the pelvic curvature of the forceps is positioned in the same direction
as the maternal pelvic curvature and the cephalic detachment occurs in the OP variety,
with no need for a second grip.[9]
[20]
A third technical option for the posterior varieties, which also has the advantage
of cephalic detachment in the OP variety, is to perform the 135° rotation by means
of Scanzoni’s maneuver (double grasp) using a Simpson’s forceps. The technique is
useful when Kielland’s forceps are not available and/or when there is an operator
with dexterity and appreciation of the procedure. The first application is performed
with the pelvic curvature of the forceps directed upwards, towards the fetal bregma.
After a 135° rotation performed with a wide circumduction movement of the handles,
the pelvic curvature of the forceps is directed downwards and the cephalic pole in
the OP variety. As Simpson’s forceps blades have a wide pelvic curvature, the instrument
must be removed for a second application, and extraction of the cephalic pole with
the pelvic curvature of the blades facing downwards is prohibited. The second grip
follows the principles for application and detachment of the fully rotated cephalic
pole.[9]
[20]
Among these three techniques in posterior presentations, the 135° rotation with Kielland’s
forceps in a single grip is undoubtedly the most advantageous as it promotes detachment
in the OP variety, with a reduction in vaginal manipulation and use of force.[9]
[20]
Kielland’s forceps are the most indicated for application in transverse varieties
(right occiput transverse [ROT] and left occiput transverse [LOT]). The option of
applying the anterior branch first is advantageous, as it requires a wide Lachapelle
maneuver, which can be hampered when one chooses to apply the first branch posteriorly
in the pelvis. As this displaces the cephalic pole anteriorly, insertion of the anterior
branch by means of the triple spiral movement is made difficult. Thus, the first branch
is applied anteriorly, through movements of translation, lowering and twisting of
the handle (Lachapelle maneuver - itinerant technique) ([Figure 18]). The second branch is introduced later, directly. Asynclitism is often present
in these position varieties, requiring its correction prior to assessment of the correct
grip, rotation and traction. For this, one of the branches must penetrate more than
the other in the birth canal, depending on the type of asynclitism (anterior or posterior).
The correction for the synclitism position is performed by sliding the already articulated
branches of the forceps. It is recommended to pull the branch that penetrated the
most into the birth canal, avoiding to push the branch that penetrated the least in
order to avoid trauma to the upper portions of the birth canal. Correction of asynclitism
is confirmed using Laufe’s criteria, before performing rotation (“key through the
keyhole”) and traction.[9]
[20]
Source: Adapted from Benzecry (2006).[9]
Figure 18. Application of the right branch of Kielland’s forceps to the anterior parietal bone
by means of the Lachapelle maneuver (translation, lowering and torsion of the handle)
in the left occiput transverse position
Because it has larger branches and ample perineal curvature, Piper’s forceps are the
most indicated for impaction of the head (breech baby) ([Figure 2]). In the technique, an assistant lifts the body of the fetus by the lower limbs
or with a compress positioned under the fetal abdomen. Positioned horizontally, the
left branch is introduced first, directly. Subsequently, the right branch is introduced
in a similar way without greater difficulty in articulating with the left branch.
When assessing the correct grip, the facial line must be equidistant from the articulated
branches of the forceps, the finger must not penetrate through the fenestrae of the
blades and the chin must be close to or at most 1.5cm from the plane of the shanks.
In the previous varieties, the application is performed in OP with the branches introduced
under the fetal body. Traction should be axial, following the curvature of the maternal
pelvis until the suboccipital region is positioned under the pubic arch. The head
is extracted by accentuating the flexion and subsequently moving the articulated instrument
towards the maternal abdomen. The instrument must be disarticulated before complete
extraction of the cephalic pole ([Figure 19]).[9]
Source: Photographic record by the authors.
Figure 19. Application of Piper’s forceps on the stuck head with the occiput positioned anteriorly
(occiput posterior position)
In the later varieties, the branches are introduced over the fetal body and the application
takes place in the OA. Traction is exerted forward, with the mandible and fetal neck
resting on the superior border of the pubic symphysis. The fetal trunk is then elevated
towards the maternal abdomen.[9]
How should the sequencing of instruments and handling be done in the face of failed
attempts at operative vaginal delivery?
How should the sequencing of instruments and handling be done in the face of failed
attempts at operative vaginal delivery?
The sequential use of forceps and vacuum is associated with increased rates of cerebral,
subdural, and subarachnoid hemorrhage in newborns, as well as facial nerve and brachial
plexus injuries. Severe perineal lacerations are also more common.[21] The effectiveness in resolving operative vaginal delivery is greater with forceps
than with vacuum extractors. Therefore, after a failed attempt at vacuum extraction,
the risks of a subsequent attempt at forceps must be weighed against the risks of
a cesarean section. In contrast, in situations where the forceps attempt fails, the
attempt at vacuum extraction is contraindicated, and the subsequent cesarean section
must be performed.[22] Before performing the cesarean section, it is recommended to de-impact the cephalic
pole by means of maneuvers or other instruments (Coyne, Sellheim or Murless levers;
C-Snorkel; fetal pillow).[23]
What is the role of ultrasound in operative vaginal delivery?
What is the role of ultrasound in operative vaginal delivery?
Ultrasonography can be used to confirm the diagnosis of the variety of position and
height of the cephalic pole, helping to assess the probabilities of success and the
risks of operative vaginal delivery. It has also been described in the objective monitoring
of rotational applications. The parameters evaluated when determining the position
and variety of position are the cerebellum, orbits and midline falx. Ultrasonographic
measurements of head circumference, the distance between the perineum and the fetal
skull, and the angle of progression are predictive of difficult operative vaginal
deliveries. Studies reveal that ultrasound increases the diagnostic accuracy of positional
variety with no differences in maternal or neonatal outcomes.[24] Therefore, there is still not enough evidence to recommend the routine use of abdominal
or perineal ultrasound for assessment of the station, flexion and descent of the fetal
head in the second stage of labor.[5]
What are the recommendations for episiotomy, antibiotic prophylaxis, and thromboprophylaxis
in operative vaginal delivery?
What are the recommendations for episiotomy, antibiotic prophylaxis, and thromboprophylaxis
in operative vaginal delivery?
Operative vaginal delivery is one of the indications for episiotomy, which must be
selective. Current recommendations do not advocate routine episiotomy in operative
vaginal delivery given the poor healing and discomfort associated with mediolateral
episiotomy, and the risk of injury to the anal sphincter and rectum with median episiotomy.[4]
[25]
[26] However, in the context of instrumental delivery, episiotomy is presented as a risk
modifying procedure, and not as a treatment for severe perineal lacerations. The search
for the best scientific evidence regarding the effect of episiotomy on the risk of
severe perineal lacerations in operative vaginal delivery, to be obtained through
randomized clinical trials, is hampered by the challenge of composing dichotomized
groups into 0% and 100% performance of the procedure, as well as in biases introduced
by the heterogeneity of operators’ skills and the difficulty in ensuring that an appropriate
incision angle (between 40° and 60°) is always obtained in the intervention group.
Therefore, the value of large observational studies remains, which demonstrate that
mediolateral episiotomy can play an important role in preventing severe perineal lacerations
during operative vaginal delivery.[27] Selecting parturients for undergoing or not an episiotomy during operative vaginal
delivery requires operator experience and skill, especially when opting for posterior
cephalic detachment (OA). The moment of the episiotomy should not precede the test
of traction and the rotation maneuvers, avoiding the performance of the procedure
in the event of a failed attempt at operative vaginal delivery. Therefore, after the
descent of the presentation, with the occiput below the pubic symphysis, in the anterior
detachment (OP), the elevation of the cephalic pole begins by means of the displacement
of the articulated handles of the forceps towards the maternal abdomen and the evaluation
of the need for episiotomy.[28]
[29] A single intravenous dose of antibiotics is recommended in operative vaginal delivery,
as it significantly reduces the likelihood of infection and has few adverse events.
Correct asepsis techniques and the use of personal protective equipment are also advised.[30] After operative vaginal delivery, puerperal women should be reassessed for the risk
of venous thromboembolism and the need for thromboprophylaxis. Risk factors, such
as prolonged labor and immobility are frequently associated with instrumental delivery.[31]
What are the main maternal and neonatal complications of operative vaginal delivery?
What are the main maternal and neonatal complications of operative vaginal delivery?
When used in the correct technique, forceps and vacuum extractors have low rates of
maternal and neonatal complications.[4]
[5]
[32] Maternal complications associated with the use of forceps are lacerations in the
birth canal (uterine, cervical and/or vaginal), severe perineal lacerations (third
and fourth degrees), prolonged episiotomy, bladder and/or urethral injuries, and hematomas.[33] Neonatal complications associated with forceps include subgaleal hemorrhages, abrasions,
facial lacerations, ocular compressions, corneal abrasions, paralysis of the facial
and/or hypoglossal nerves, cervical spine injury, skull fracture, and intracranial
hemorrhage.[4]
[5]
[34]
[35] Third- and fourth-degree (severe) perineal lacerations are also maternal complications
related to vacuum extraction, but in smaller proportions than instrumental delivery
with forceps. The main neonatal complications in vacuum extraction occur because the
traction is applied to the scalp. The main ones are scalp lacerations, cephalohematomas
and intracranial, subgaleal and retinal hemorrhages. Cephalohematomas are more frequently
associated with application errors (cups attached outside the flexion point) and failures
in fetal extraction. They are more likely to occur with increasing duration of vacuum
extractions.[36] Even though there is association between operative vaginal delivery and severe perineal
lacerations, pelvic floor function and sexual function scores within one year of delivery
do not appear to differ in relation to cesarean delivery.[37] Obstetricians should be trained to recognize and treat maternal complications. Neonatologists
should be informed about the technique used in operative vaginal delivery in order
to assess and observe potential associated neonatal complications.[4]
[5]
What should analgesia and urinary tract care be like after operative vaginal delivery?
What should analgesia and urinary tract care be like after operative vaginal delivery?
Postpartum analgesia with non-steroidal anti-inflammatory drugs and paracetamol should
be routinely performed after assisted birth with forceps or a vacuum extractor.[38] Postpartum women should be instructed about the risk of urinary retention present
with the association between analgesia and operative vaginal delivery. They should
be encouraged to empty their bladder in the postpartum period and have their urinary
time and volume (including residual volume) monitored. Intermittent or even indwelling
urinary catheterization may be necessary for 24 to 48 hours. In more lasting bladder
dysfunctions, urological evaluation and clean intermittent self-catheterization may
be necessary. Physical therapy can be offered as a strategy to reduce the risk of
urinary retention within three months of delivery.[39]
Final considerations
In the evolution of childbirth care, forceps are the resource with the greatest potential
to save lives. Although vacuum extractors are more recent, they are also effective
devices for assisted birth and offer the advantage of simplifying the operative technique.
With adequate knowledge and skill, the cost-effectiveness and safety of instrumental
vaginal delivery are favorable and endorse current guideline recommendations for operative
vaginal delivery. Despite the obvious advantages, the potential of operative vaginal
delivery is currently limited both by ignorance and misuse. The progressive replacement
of forceps and vacuum extractors by cesarean section motivated by the lack of preparation
of the new generation of obstetricians seems to introduce a real possibility of the
disappearance of these instruments from the medical practice of childbirth care. The
emergence of new instruments that although less effective, require less technical
skill from the operator seems to be a reflection of the current inabilities of obstetricians
for operative vaginal delivery. Therefore, training in these important skills must
be urgently reconsidered, before this art is lost forever.
National Specialized Commission on Obstetric Emergencies of the Brazilian Federation
of Gynecology and Obstetrics Associations
President:
Álvaro Luiz Lage Alves
Members:
Gabriel Costa Osanan
Samira El Maerrawi Tebecherane Haddad
Adriana Amorim Francisco
Alexandre Massao Nozaki
Brena Carvalho Pinto de Melo
Breno José Acauan Filho
Carla Betina Andreucci Polido
Eduardo Cordioli
Frederico José Amedée Peret
Gilberto Nagahama
Laíses Braga Vieira
Lucas Barbosa da Silva
Marcelo Guimarães Rodrigues
Rodrigo Dias Nunes
Roxana Knobel
