Operative vaginal deliveryPresented to obst./gyne. Department by:

كاظم سلمان وائل6th class college of medicine

operative vaginal delivery refers to any surgical procedure designed to

expedite vaginal delivery, and includes episiotomy, forceps

delivery and vacuum extraction.

Assisted vaginal delivery

The incidence of instrumental intervention varies widely both within and between

countries and may be performed as infrequently as 1.5 per cent, or as often as

26 per cent. These differences are often related to variations in labour ward

management.

In Iraq 42.1% of hospitals are able to provide assisted

vaginal delivery(*)

(*)http://www.ncbi.nlm.nih.gov/pubmed/19946792 from an article "Challenges to the provision of emergency obstetric care in Iraq"

Instruments

Forceps

• The obstetric forceps consists of 2 matched parts that articulate, or “lock.” Each part is composed of a blade, shank, lock, and handle

Classification of forcepses1.Classic forceps (such as Simpson

forceps), which have a pelvic curvature, a cephalic curvature, and locking handles.

• 2.Rotational forceps (such as Kielland forceps), which lack a pelvic curvature and have sliding shanks.

• 3.Forceps designed to assist breech deliveries (such as Piper forceps), which lack a pelvic curve and have long handles on which to place the body of the breech while delivering the head.

Maternal & Fetal Indications for Forceps Delivery

• Maternal and fetal indications for forceps delivery include circumstances in which continuation of the second stage of labor would constitute a significant threat to the mother or the baby, as well as those circumstances in which the mother can no longer satisfactorily assist in delivering the infant as with regional anesthesia.

A. MATERNAL INDICATIONS

The second stage can be shortened in cases of exhaustion, severe cardiac or pulmonary problems accompanied by dyspnea.

B. FETAL INDICATIONSThe most common fetal indications are those concerning malpositions of the fetal head (occipito-transverse and occipito-posterior). Such positions occur more frequently with regional anaesthesia as a consequence of alterations in the tone of the pelvic fl oor that impede spontaneous rotation to the optimal occipito-anterior position.

occipito-transverse occipito-posterior Normal occipito-anterior position

• The primary fetal indication for terminating the second stage prematurely is fetal heart tones (FHTs) with a rate persistently less than 100 or more than 160 beats/min, late deceleration patterns, or gross irregularity.

Prerequisites for any instrumental delivery

o The cervix must be fully dilated. (except second twin and rare other situations).

o The membranes must be ruptured.o The head must be engaged to a station 0 or below.o The head must present correctly.o There must be no significant cephalopelvic disproportion.o Empty bladder/no obstruction below the fetal head (contracted

pelvis/pelvic kidney/ovarian cyst, etc.).o Adequate analgesia/anaesthesia.o A knowledgeable and experienced operator with adequate preparation to

proceed with an alternative approach if necessary.o An adequately informed and consented patient (consent must be sought

though not necessarily written).

FORCEPS DELIVERY: POSITION OCCIPUT ANTERIOR

• Technique• By convention, the left blade is inserted before the

right with the accoucheur’s hand protecting the vaginal wall from direct trauma.

• The same is performed by right blade

• With proper placement of the forceps blades, they come to lie parallel to the axis of the fetal head and between the fetal head and the pelvic wall.

• The operator then articulates

and locks the blades, checking their application before applying traction.

• Traction should be applied intermittently in concert with uterine contractions and maternal expulsive efforts. The axis of traction changes during the delivery and is guided along the ‘J’-shaped curve of the pelvis. As the head begins to crown, the blades are directed to the vertical, and the head is delivered.

Forceps Delivery in Face Presentation

• If the chin is anterior, the same indications, conditions, and stipulations apply for forceps delivery as in the OA position. The classic forceps are applied to the occipitomental diameter of the head); elevating the handles as the head advances causes the chin to come under the symphysis, and the occiput emerges posteriorly.

Forceps Delivery in Brow Presentation

• Some brow presentations convert to an occiput presentation spontaneously during the first stage of labor or can be converted to either occiput or face presentation, in which case labor should be managed accordingly. If a brow presentation fails to convert to a favorable position (chin anterior or occipital presentation) or cannot be converted readily, the infant must be delivered by cesarean section.

Forceps Delivery in breech presentation

• Piper's forceps have a perineal curve to allow application to the after-coming head in breech delivery.

• The basic premise of such instruments is that a suction cup, of a silastic or rigid construction, is connected, via tubing, to a vacuum source .

• Either directly through the tubing or via a connecting ‘chain’, direct traction can then be applied to the presenting part to expedite delivery.

Metal venouse cup;

silicone rubber cup

Recent developments have removed the need for cumbersome external suction generators and have incorporated the vacuum mechanism into ‘hand-held’ pumps, e.g. OmniCup™.

Such devices appear to be more acceptable to patients than standard equipment and have no obvious effects on instrumental delivery success or on the incidenceof maternal or fetal complications, but large trials have yet to be performed.

Technique• Soft cups are

significantly more likely to fail to achieve vaginal delivery than rigid cups, however, they are associated with less scalp injury. There appears to be no difference in terms of maternal injury.

• The soft cups are appropriate for straightforward deliveries with an occipitoanterior position; metal cups appear to be more suitable for ‘occipitoposterior’, transverse and difficult ‘occipitoanterior’ position deliveries where the infant is larger or there is a marked caput.

• For successful use of the ventouse, determination of the flexion point is vital. This is located at the vertex, which, in an average term infant, is on the saggital suture 3 cm anterior to the posterior fontanelle and thus 6 cm posterior to the anterior fontanelle. The centre of the cup should be positioned directly over this, as failure to do so will lead to a progressive deflexion of the fetal head during traction, and an inability to deliver the baby.

Ant.fontanelle

3 cm

6 cm

post.fontanelle

• The operating vacuum pressure for nearly all ventouse is between 0.6 and 0.8 kg/cm2. It is prudent to increase the suction to 0.2 kg/cm2 first and then to recheck that no maternal tissue is caught under the cup edge. When this is confirmed the suction can then be increased.

• Traction must occur in the plane of least resistance along the axis of the pelvis – the traction plane.This will usually be at exactly 90؛ to the cup and the operator should keep a thumb and forefinger on the cup at the traction insertion to ensure that the traction direction is correct and to feel for slippage. Safe and gentle traction is then applied in concert with uterine contractions and voluntary expulsive efforts. With the ventouse, the operator should allow no more than two episodes of breaking the suction in any vacuum delivery, and the maximum time from application to delivery should ideally be less than 15 minutes. Rotation is achieved by the natural progression of the head through the pelvis.

is not acceptable to use a ventouse when:

• The position of the fetal head is unknown.

• There is a significant degree of caput that may either preclude correct placement of the cup or, more sinisterly, indicate a substantial degree of cephalopelvic disproportion.

• The operator is inexperienced in the use of the instrument.

Choice of instruments for assisted vaginal delivery according to WHO

• For situations in which there is no clear clinical indication for a specific instrument to facilitate delivery, the findings of this review support the use of vacuum extraction as the first-line method for assisted birth. When a relatively easy procedure is anticipated, soft-cup vacuum extraction is indicated. When it is expected that more traction force may be needed, vacuum extraction with a metal cup should be the method of choice, except in women known to have HIV or hepatitis infection.

The ventouse, when compared to the forceps is signifi cantly more likely to:

• fail to achieve a vaginal delivery;• be associated with a cephalohaematoma (subperiosteal bleed);• be associated with retinal haemorrhage;• be associated with maternal worries about the baby; and is signifi cantly less likely to be associated with:• use of maternal regional/general anaesthesia;• signifi cant maternal perineal and vaginal trauma;• severe perineal pain at 24 hours; and is equally likely to be associated with: delivery by Caesarean section; low 5 minute Apgar scores.

ADDITIONAL NOTES*Failures can occur when:

1. the choice of instrument is wrong (e.g. a silastic cup ventouse for a rotationaldelivery),

2. when the positioning of the ventouse cup is wrong or 3. when the position has been wrongly defined, leading

to inappropriately large diameters presenting to the pelvis. Failure is also more common if the fetus is large or maternal effort is poor.

the rates of third- and fourth-degree tears are higher when a second instrument is used.(so failure of forceps delivery contraindicate the use of ventouse & vice-versa.

Complications of instrumental vaginal delivery

• Maternal deaths have been reported with vacuum deliveries, associated with cervical tears in women delivered before full dilatation.

• Traumatic vaginal delivery is considered the most important risk factor for faecal incontinence in women .

• Postpartum haemorrhage is more common in women needing instrumental vaginal delivery compared to women who deliver

• spontaneously, but less common than in women delivered by Caesarean section in the second stage.

• Measures to limit this include:1. prophylactic syntocinon infusion post

delivery;2. prompt suturing;3. careful identifi cation of high tears.

• Fetal complications are no less important; the incidence of cephalhaematoma is increased with the use of the ventouse, and there are rare reports of severe intracranial injuries.

References

• CURRENT Obstetric & Gynecologic Diagnosis & Treatment, 9th Edition

• Ten Teachers, 19E - Kenny, Louise, Baker, Philip N• Obstetrics & gynecology At a Glance, 4th edition.• Netters Obstetrics and Gynecology.2nd.Ed• http://www.ncbi.nlm.nih.gov/pubmed