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Comparative study of delivery by vacuum extractor and forceps
Comparative study of delivery by vacuum extractor and forceps J. D.
G. M.
Jerusalem,
SCHENKER, SERR,
M.D. M.D.
Israel
Three hundred cases of vacuum extraction were compared with 300 forceps deliueries in order to evaluate their relative safety to mother and child.. The age and parity of the patients and the indications were similar in the two series. The incidence of maternal complications following vacuum extraction was significantly smaller (17.8 per cent) than that following forceps delivery (38.1 per cent). In selected cases vacuum extraction obviated the necessity for cesarean section. Fetal complications were almost similar to those seen following forceps delivery. The rate of fetal complications increases considerably if traction time is longer than 15 minutes and if the cervix is incompletely dilated. The vacuum extractor was found to be an eipicient instrument with special indications, but cannot be accepted as a general replacement for forceps.
T H E u s E of a vacuum for the purpose of hastening delivery was first attempted by Yongel in 1706 and others followed suit at intervals using similar methods.2-5 In 1954 Malmstrijm’ described his instrument as a means of assisting the contractions of labor in cases of secondary uterine inertia. In 1957 he7 described the use of the vacuum extractor for direct traction on the fetus. Since then, the use of the vacuum extractor has been accepted, especially in the Scandinavian countries and Western Europe. The equipment used in the Hadassah University Hospital, Jerusalem, is the electric vacuum apparatus with the standard Malmstrijm cups. Its advantage is that the obstetrician is able to contro1 the pressure flow by means of a foot pedal, thus obviating the need for an assistant. The purpose of this paper is to review our experience in 300 deliveries by the vacuum extractor with their obstetrical indications, and to compare them with a similar
From the Department Obstetrics-Gynecology, University Hospital.
number of deliveries by forceps, from the point of view of advantages and trauma of the respective instruments to the mother and baby. Case material Our cases include 300 deliveries assisted by the vacuum extractor at the Hadassah HOSpital, Jerusalem, from April, 1962, until January, 1965. The number of deliveries in the above period was 5,264. The 300 vacuum extractions constituted 5.7 per cent of all births, and are compared with 300 forceps deliveries during the years 1957 until 1960, when the vacuum extractor was not yet used in our Department, representing 3.9 per cent of a11 births. Two hundred one (60.6 per cent) of all women who were delivered by the vacuum extractor and 243 (81 per cent) of those delivered with forceps were primiparas. It should be pointed out that the obstetrics practiced in our department is conservative, based on natural childbirth with liberal use of analgesia. This accounts for the low incidence of instrumental deliveries (Table I).
of Hadassah
32
Volume Number
98 1
Vacuum
Table I. Basic characteristics
of clinical
extractor
forceps
33
material NO.
Total deliveries, April, 1962, to January, By vacuum extractor With head above spines With head below spines Total deliveries, 1957- 1960 By forceps With head above spines With head below spines By cesarean section Multiparas delivered by vacuum extractor Primiparas delivered by vacuum extractor Vacuum extractor applied with cervix incompletely dilated
and
1965
%
I
5,064 300
5.7 123 176
41.0 59.0
7,695 300
3.9 27.0 73.0
251
4.7 29.6 70.4 11.0
2:; 33
Table II. Indications Vacuum
extractor
Forceps
Parity i
Indications Prolonged second stage Persistent occipitoposteriof Fetal distress Uterine scar Deep transverse arrest Cardiac disease Toxemia Elderly primipara Bigemini (twins) Chronic lung disease Prolapse of umbilical cord Compound presentation Epilepsy Myopia gravis Imminent rupture of uterus Rupture of sinus marginalis Previous Lash operation Frank breech Partial abruptio placentae Placenta previa marginalis
82 23 35 15 8 6 8 4 2 2 6 1
iii or Total no. I more I of cases
ii
I
10 4 IO 11 1 : 3 1 3 1
7
1; : 2 r T 7
4
T -
-
Prematurity Pulmonary infarct Subcutis
Parity
emphysema 201
Total
Indications
for vacuum
47
extraction
It is generally accepted that the indications for using the vacuum extractor are manifold because it can be used on an incompletely dilated cervix, and in wide variations of levels and positions of the fetal head in the pelvis. While it is true that
52
99 31 60 18 18 16 12 8 9 3 7 6 2 3 2 2 1 1 1 -
i
iii or I more
ii 3 2
62
10 10
14
2
; 11 2 4
1 -
a -
-
T -
5
T
2 1 -
5 2 1
T 300
I
243
1 31
Total
i
of
no. cases
1 3 8 1 8 I 1
85 35 80 11 24 10 8
T
113
T -
94 -
T -
t 6 2 1
26
3 1 -
300
MaImstrom originahy intended the vacuum extractor for improving the contractions of the first stage of labor, present-day usage is much wider, including shortening of the second stage and repositioning of the fetal head. The indications may be either maternal
34
Schenker
May 1, 1967 Am. J. Obst. & Gynec.
and Serr
or fetal and include prolonged second stage, uterine inertia, maternal exhaustion, cardiac or pulmonary complications, severe toxemia, previous uterine scar, fetal distress, and prolapse of the cord. The indications in our cases are summarized in Table II. In cases with more than one indication, only the principal one is mentioned. In 140 (46.6 per cent) casesof vacuum extraction and 155 (51.3 per cent) of forceps delivery, intervention was decided upon because of lack of progress in labor, either from secondary uterine inertia or maternal exhaustion. In 31 ( 10.3 per cent) casesof vacuum extraction and 35 (12.6 per cent) of forceps delivery there was persistent occipitoposterior position of the head, while 18 (6 per cent) casesof vacuum extraction and 24 (8 per cent) of forceps delivery were performed for deep transverse arrest. Fetal distress. Fetal distress was the principal indication in 67 (22.3 per cent) deliveries by the vacuum extractor, 31 of these being in multiparas, where it was impossible to perform forceps delivery because of incomplete dilatation of the cervical OSor the high position of the head in the pelvis. In forceps delivery fetal indications accounted for 89 cases (29.6 per cent), not a signifi-
cantly higher rate than in delivery with the vacuum extractor. Maternal indications. In 35 cases ( 11.6 per cent) of vacuum extraction and 28 (9.3 per cent) of forceps delivery there was a clear-cut reason to prevent undue maternal exertion such as cardiac or pulmonary diseasesor myopia gravis. The use of the extractor in 18 (6 per cent) casesof uterine scar with no case of uterine rupture is worth noting. The state of labor at the time application of the cup
Contractions. In 77 cases (29 per cent), secondary uterine inertia was the outstanding feature, treatment being a combination of intravenous Pitocin infusion and vacuum extraction. Fifty-eight of these patients were primiparas. Cervical dilatation. One of the advantages of the vacuum extractor as opposed to forceps delivery is the possibility of use before complete dilatation of the cervix with the head level high in the pelvis. Dilatation was complete at the start of extraction in 267 cases (89 per cent) ; in the other 33 (11 per cent) dilatation varied from three and a half fingerbreadths to almost complete or dilatation with the anterior lip of the cervix remaining. Most of these latter patients were multiparas. The results are shown in Table III.
Table III. Incomplete dilation of the cervix at the time of application of the cup
) of cases
i
) ii
) iii
) iv
15
5
6
3
)
v
] x
3
1
level
of the head
Table IV summarizes the particulars of the level of the head in the pelvis at the time of application of the vacuum extractor, according to DeLee’s classification.
Parity
No.
of
Table IV. The level of the head at the time of application of the vacuum extractor Level Pelvic Ischial Ischial Ischial Ischial
inlet spines spines spines spines
-2 -1 +1
Total Note:
i
ii
1 4 50 108 38
7
201 One
birth
was a breech
presentation.
:Y 1 47
Parity .. . 111
iv-v
vi-x
xi
6 12 3 1
3 2 6 1 -
1 5 5 2 1
1 1 ! -
6 25 92 135 41
22
12
14
3
299
Total
Volume Number
98 1
In 6 cases (2 per cent) the head was at the level of the pelvic inlet. In 5 of these cases the vacuum extractor was applied because of fetal distress, 2 with prolapse of the cord. The five mothers were multiparas. There was one case of a primipara who was a cardiac patient. In 25 cases (8.3 per cent) the head was at a level higher than the ischial spines, while in 227 (75.5 per cent) the level of the head corresponded to a midforceps application. In only 41 women (13.6 per cent) did the level correspond to a low forcers application. In the 300 forceps deliveries there was no case of high forceps, and in 81 cases (27 per cent) midforceps deliveries were carried out and the rest were low or outlet forceps deliveries.
Abnormal position of the head in the pelvis and other obstetric pathology. The position of the head in the pelvis is important in both vacuum extractor and forceps deliveries. In 31 women with vacuum extractor and 35 with forceps there was persistent occipitoposterior position. The vacuum extractor was used in 8 cases and forceps in 24 for deep transverse arrest. With regard to other obstetric abnormalities, the vacuum extractor was used in 6 cases of compound presentation (including hand alongside head, but excluding in these series prolapse of the cord). There were 9 cases of twinning and in 6 of these the vacuum extractor was applied to the first twin. In one case of breech presentation the extraction was without success. Delivery In 280 cases (93.3 per cent) in which the vacuum extractor was applied, delivery was brought to a successful termination, In 10 cases (3.3 per cent) a start was made with the vacuum extractor when fetal distress developed and the head was still too high for forceps to be applied. The head was brought down with the vacuum extractor and then forceps were applied because of mounting fetal distress. In 5 cases the cup slipped off a number of times (up to a maximum of 3 was allowed) and then the delivery was concluded with forceps. In
Vacuum
extractor
and forceps
35
4 cases with incomplete dilatation of the cervix and the head at a high level in the pelvis, vacuum extraction was attempted because of fetal distress, but was unsuccessful and these women were delivered by cesarean section. Another unsuccessful case was that of a breech presentation. In the forceps deliveries there was no case of so-called failed forceps. Changes in the during extraction
fetal
heartbeat
In 67 cases (22.3 per cent) the indication for vacuum extraction was fetal distress. In some of these, fetal distress increased during extraction and was apparently due to a short umbilical cord or the cord being tight around neck or limbs. In 10 such cases, as noted, the deliveries were concluded with the aid of forceps. Duration
of extraction
The duration of vacuum extraction depends on a number of factors-contractions, cervical dilatation, level and position of the head in the pelvis, and size of the fetus. The patient generally received intravenous Pitocin infusion in order to enhance uterine contractions when necessary, and extraction was more prolonged where the cervix was incompletely dilated or the head was at a high level in the pelvis. Table V gives the number of cases according to the duration of vacuum extraction in minutes. The cases where extraction time was not recorded in the chart are known to be less than 5 minutes. In 158 cases (50.6 per cent), the time of extraction was not more than 5 minutes and in only 4 cases ( 1.3 per cent) reached 20 minutes. In 3 cases (1 per cent) lasting more than 15 minutese, the babies showed central nervous system injury. These 3 represent half the number of cases where application lasted more than 15 minutes (see Table V). Two died of cerebral hemorrhage and another showed signs of transient spasticity and hemorrhagic cerebral spinal fluid.
36
Table
Schenker
May
and Serr
V. Duration
Am.
of traction
I No.
Table
vacuum
l-5
)
Maternal
complications
of
6-10
1
extraction
11-15
92
during
1
25
No.
Complication
16-20
)
20+
Unrecorded
2
4
vacuum
extractor )
%
Postpartum hemorrhage Postpartum fever Thrombophlebitis Cervical laceration Third-degree perineal tear Vaginal and perineal laceration Urethral injury Difficulties in micturition Pulmonary embolism Prolapse of uterus
28 17 3 1 1 3 0 0 0 1
9.3 5.6 1.0 0.3 0.3 1.0 0 0 0 0.3
Total
54
17.8
Anesthesia MalmstrGme claims that in vacuum extraction there is no necessity for general anesthesia except in cases requiring correction of pathologic positions such as version from persistent occipitoposterior, compound presentations, or with the head at a high level in the pelvis. He recommended pudental block or infiltration. Other workers81 g do not use any a nesthesia at all. In our series general anesthesia was employed in 10 cases of combined vacuum extraction and forceps delivery. Pudendal block or infiltration was used in some cases. Of the forceps deliveries 85 per cent were under general anesthesia and the rest under pudendal block. of the genital
in minutes
19
and after delivery With
lacerations
1, 1967 & Gynec.
extractor Time
158
of cases
VI.
with
J. Obst.
tract
All primiparas delivered with forceps had episiotomies. Episiotomy was performed in 204 (68 per cent) of all patients delivered by vacuum extractor. There was one episiotomy which extended to a third-degree perineal tear in both forceps and vacuum extractor deliveries. In one case of vacuum extraction, cervical laceration resulted when
With I
NO.
27 46 5 1 1 27 2 5 1 0 115
force@ I
% 9.0 15.3 1.6 0.3 0.3 9.0 0.6 1.6 0.3 0 38.0
the cup was attached with incomplete dilatation. A few other perineal tears were encountered in vacuum extraction while additional perineal and vaginal tears were found in 27 (9 per cent) cases of forceps delivery. Third
stage
of labor
Twenty-eight women (9.3 per cent) who were delivered by vacuum extractor and 27 (9 per cent) by forceps delivery had postpartum hemorrhage and needed biood transfusions. Manual removal of the placenta was necessary in 7 cases of vacuum extraction (2.5 per cent) and 9 (3 per cent) of forceps delivery. Exploration of the uterine cavity was required in 4 cases of vacuum extractor (1.3 per cent) and 6 (2 per cent) of forceps delivery. Puerperal complications Most authors?? “7 “9 ” claim that puerperal complications following Vacuum extraction are fewer than after forceps delivery. The results in this series are shown in Table VI. Seventeen (5.6 per cent) women after vacuum extraction had postpartum fever of genital tract origin, in com-
Volume 98 Number 1
Table VII.
Vacuum
Birth
of infants vacuum of infants forceps
Table VIII.
(UP to 2,000 12,001-2,500 I2,5OI-3,000
delivered extractor delivered
Perinatal
-
26
36
119
a7
32
8
12
61
128
71
20
2,500
grams
Complications : Cephalhematoma Hypoxia Transient central nervous system injury Intracerebral hemorrhage Severe jaundice Superficial abrasions Fracture of cranium Facial nerve paralysis Erb’s palsy Permanent central nervous system injury Infected cephalhematoma
Forceps I
No.
I
%
45
1.6 1.2
67
26
8.6
20
6:s
12
4.0 2.6 (2 died)
15 14
i:i
8 3 2 11 15
(2 died)
4
1.3
0.6 (2 died) 3.6 5.0
4 5
1.3 (4 died) 1.6
1
0.3
1
0.3
neonate Weight. The weight of the infants in these series was between 1,750 grams and 5,600 grams (Table VII). Complications. The complications have been divided according to their anatomic location-scalp, skull, and central nervous system-as well as being classified as temporary or permanent. One of the transient phenomena in the scalp is the inevitable caput succedaneum of vacuum extraction, the so-called “chignon.” Its size depends on the size of the cup attached to the fetal scalp, and it tends to disappear soon after birth. In 300 deliveries by vacuum extractor 5
g
1.0
-
parison to 46 (15.3 per cent) following forceps delivery; 200 women (66.6 per cent) after forceps delivery received prophylactic antibiotics, as opposed to 146 (48.6 per cent) after vacuum extraction. The
37
complications
Total Perinatal perinatal deaths deaths due to delivery under
forceps
~3,OOZ-.?JOO 13,502-4,000 1 4,001+
Vacuum extractor No. I %
Infants
and
weight
Weight in grams No. by No. by
extractor
12 1 1 1
-
4.0 0.3 0.3 0.3
babies (1.6 per cent) died. Two deaths (0.6 per cent) were directly ascribable to the use of the vacuum extractor, postmortem findings being multiple cerebral hemorrhages. Traction in both these cases continued more than 20 minutes. Two others died during birth from prolapse of the cord and one child died because of a severe congenital cardiovascular defect. Six infants (2 per cent) presented severe asphyxia which responded well to routine resuscitation with or without intubation. The “chignon” on the child’s scalp disappeared in most instances within 24 hours except for 12 (4 per cent) cases with cephalhematoma. A high percentage of babies showed minor lacerations in the area occupied by the cup, but on discharge from the hospital, at an average of five days later, only 15 (5 per cent) still showed signs of erosion in the scalp. Three infants (1 per cent) showed signs of transient central nervous system
38
Schenker and
Serr
damage. One of these had hemorrhagic cerebrospinal fluid, and 2 of them had endured traction for close to 20 minutes. One infant still shows signs of damage to the central nervous system, with marked regression in development. In this case traction was applied with the cervix incompletely dilated and the head still at a high level in the pelvis and was continued for 15 minutes. Eleven infants (3.6 per cent) developed severe jaundice; of these 2 had ABO incompatibility; one had Rh incompatibility; and 5 (1.6 per cent) cases were apparently caused by the cephalhematoma. With regard to birth trauma following forceps delivery, 7 infants died (2.3 per cent) and in 4 (1.3 per cent) of them postmortem findings showed cerebral hemorrhages and tentorial lacerations. Two died at birth from severe asphyxia. Four (1.3 per cent) showed signs of injury to the central nervous system. The percentage of cephalhematomas and superficial abrasions was almost identical to that of vacuum extraction. Facial nerve palsy was recorded in 4 cases, and skull fracture in one. These results are shown in Table VIII. Comment and conclusions The vacuum extractor as an additional obstetric instrument was enthusiastically received in labor wards in many parts of the world”? 11, I31 I4 and in some places was accepted as an almost complete substitute for the forceps. Two publicationP9 I6 enthusiastically reported the vacuum extractor to be rapidly replacing the forceps, but there still occurred polemics in the literature between those who claimed the vacuum extractor will diminish or even replace the use of the forceps, and those who claim that its use is limited to certain specific indications.12’ IT In order to obtain an accurate comparative evaluation of the two instruments it would be necessary to carry out a double blind study, a difficult challenge in clinical obstetric practice and perhaps unjustified. We have, therefore, compared 300 births by vacuum extraction to a similar number
May 1, 1967 Am. J. Obst. & Gynec.
of forceps deliveries. In our two groups the parity, birth weights, and indications for the application of the respective instruments were almost identical. The use of forceps in our Department dropped from 3.9 to 2.4 per cent with the introduction of the vacuum extractor. This low incidence of forceps deliveries, compared to that in common use in the United States is due to our different practice of obstetrics. The vacuum extractor is ‘potentially a substitute for forceps in all cases except for face and breech presentations, and in emergency cases of asphyxia. Its principal advantages over the forceps are the lack of necessity for general anesthesia, the possibility of its use on an incompletely dilated cervix and at a higher level of the head in the peIvis. However, dehvery is much slower than by the use of the forceps and hence the limitation of the vacuum extractor in cases of fetal distress. In 10 of our cases delivery by vacuum extractor was combined with outlet forceps when signs of fetal distress increased. One further advantage is in the correction of pathological vertex positions such as persistent occipitoposterior and deep transverse arrest. Many author+ I8 pointed out that delivery by the vacuum extractor could replace some cases of cesarean section, especially in protracted labor in primiparas, in fetal distress without complete cervical dilatation, or when the head is so high in the pelvis that it precludes forceps delivery. Our experience and our results with the vacuum extractor lead us to the opinion that there is no considerable reduction in the cesarean section rate, contrary to the observations of others.15, I8 The use of vacuum extraction in cases of incomplete dilatation of the cervix or when the head is at a high level in the pelvis is relatively dangerous obstetric procedure, especially to the fetus, although less so than the use of forceps. With respect to the mother, the vacuum extractor is a relatively safe instrument as compared to the forceps. However, whenever the instrument has been applied in in-
Volume
98
Number
1
complete dilatation of the cervix, postpartum inspection of the cervix is obligatory. The danger of ascending infection in the genital tract appears to be minimal (5.6 per cent) as compared to 15.3 per cent in forceps deliveries in this series. With the increased use of the vacuum extractor there have appeared publications emphasizing neonatal lesions.Gl‘II lo, I49lQmZ3 AgiieroZ4 even claimed that of 100 vacuum extractor deliveries all the infants suffered injury except for one. Brey16 showed a rate of neonatal complications in the region of 14.1 per cent in vacuum extraction, Muller,22 19.5 per cent, while our cases show 17.4 per cent. The injury to the infant is directly proportional to the duration of traction and the level of the head in the pelvis at the time of application. Therefore,
Vacuum
extractor
and forceps
39
in keeping with recent opinions, we have concluded that in order to prevent injury to the central nervous system, the vacuum extractor should be used only in caseswith clear-cut obstetric indications, and performed by an experienced obstetrician. The time of traction should not be more than 15 minutes whenever possible. In the event of complications during traction such as changes in the fetal heart rate or lack of progress, delivery should be effected either by forceps or cesarean section. A true evaluation of the advantages of the vacuum extractor in comparison to forceps as regards the infant will be possible only after a follow-up of’ a number of years. Appreciation is expressedto for
reviewing
this
Prof.
Z. Polishuk
manuscript.
REFERENCES
1. Yonge, J.: Cited by Malmstriim, T.: Acta obst. et gynec. scandinav. 36: Suppl. 3, 1957. 2. Finderle, V.: Gynecologia 133: 225, 1952. 3. Finderle, V. : AM. J. OBST. & GYNEC. 69: 1149, 1955. 4. Koller, 0.: Acta obst. et gynec. scandinav. 30: 145, lY50. (Suppl. 7.) 5. Simpson, J. Y.: Edinburgh Monthly J. M. SC. 32: 556, 1849. 6. Malmstram, T.: Acta obst. et gynec. scandinav. 33: Suppl. 4, 1954. I. Malmstrom, T.: Acta obst. et gynec. scandinav. 36: SUDD~. 3. 1957. 8. Bruniquel, 6.: and Israel, A.: GynCc. et obst. 57: 222, 1958. 9. Evelbauer, K.: Geburtsh. u. Frauenh. 19: 188, 1959. M.: Brit. M. J. 1: 165, 1963. 10. Lancet, 11. Mahnstrijm, T.: Acta obst. et gynec. scandinav. 42: Suppl. 1, 1964. 12. Schenker, J. G., and Serr, D. M.: Harefuah 57: 148, 1964. 13. Chalmers, J. A., and Fothergill, R. J.: Brit. M. J. 1: 1684, 1960.
14. 15. 16.
17. 18. 19. 20. 21.
22. 23. 24,
Lange, P.: Acta obst. et gynec. scandinav. 43: Suppl. 1, 53, 1964. Berggrin, 0. G. A.: Acta obst. et gynec. scandinav. 38: 315. 1959. Brey, J., Holtroff; J., Kinzel, W. M., and Schmidt, G.: Geburtsh. u. Frauenh. 22: 550, 1962. Chalmers, J. A., and Fothergill, R. J.: J. Obst. & Gynaec. Brit. Comm. 72: 889, 1965. DSrBler, P.: Med. Klin. 54: 1234, 1959. Boon, W. K.: Lancet 2: 662, 1961. Dessarzin, D., and Bono, S.: Gynecologia 155: 353, 1963. Lehmann, O., Andersson, H., Hansson, G., Malmstrom, T., and Ryba, W.: Acta obst. et gynec. scandinav. 42: 4, 1963. Muller, P., and Fran& R.: Strasbourg med. 11: 563, 1960. Schenker, J. G., and Gombush, G.: Obst. & Gynec. 27: 521, 1966. Agiiero, O., and Alvarez, H.: Obst. & Gynec. 19: 212, 1962.
G. M.
Jerusalem,
SCHENKER, SERR,
M.D. M.D.
Israel
Three hundred cases of vacuum extraction were compared with 300 forceps deliueries in order to evaluate their relative safety to mother and child.. The age and parity of the patients and the indications were similar in the two series. The incidence of maternal complications following vacuum extraction was significantly smaller (17.8 per cent) than that following forceps delivery (38.1 per cent). In selected cases vacuum extraction obviated the necessity for cesarean section. Fetal complications were almost similar to those seen following forceps delivery. The rate of fetal complications increases considerably if traction time is longer than 15 minutes and if the cervix is incompletely dilated. The vacuum extractor was found to be an eipicient instrument with special indications, but cannot be accepted as a general replacement for forceps.
T H E u s E of a vacuum for the purpose of hastening delivery was first attempted by Yongel in 1706 and others followed suit at intervals using similar methods.2-5 In 1954 Malmstrijm’ described his instrument as a means of assisting the contractions of labor in cases of secondary uterine inertia. In 1957 he7 described the use of the vacuum extractor for direct traction on the fetus. Since then, the use of the vacuum extractor has been accepted, especially in the Scandinavian countries and Western Europe. The equipment used in the Hadassah University Hospital, Jerusalem, is the electric vacuum apparatus with the standard Malmstrijm cups. Its advantage is that the obstetrician is able to contro1 the pressure flow by means of a foot pedal, thus obviating the need for an assistant. The purpose of this paper is to review our experience in 300 deliveries by the vacuum extractor with their obstetrical indications, and to compare them with a similar
From the Department Obstetrics-Gynecology, University Hospital.
number of deliveries by forceps, from the point of view of advantages and trauma of the respective instruments to the mother and baby. Case material Our cases include 300 deliveries assisted by the vacuum extractor at the Hadassah HOSpital, Jerusalem, from April, 1962, until January, 1965. The number of deliveries in the above period was 5,264. The 300 vacuum extractions constituted 5.7 per cent of all births, and are compared with 300 forceps deliveries during the years 1957 until 1960, when the vacuum extractor was not yet used in our Department, representing 3.9 per cent of a11 births. Two hundred one (60.6 per cent) of all women who were delivered by the vacuum extractor and 243 (81 per cent) of those delivered with forceps were primiparas. It should be pointed out that the obstetrics practiced in our department is conservative, based on natural childbirth with liberal use of analgesia. This accounts for the low incidence of instrumental deliveries (Table I).
of Hadassah
32
Volume Number
98 1
Vacuum
Table I. Basic characteristics
of clinical
extractor
forceps
33
material NO.
Total deliveries, April, 1962, to January, By vacuum extractor With head above spines With head below spines Total deliveries, 1957- 1960 By forceps With head above spines With head below spines By cesarean section Multiparas delivered by vacuum extractor Primiparas delivered by vacuum extractor Vacuum extractor applied with cervix incompletely dilated
and
1965
%
I
5,064 300
5.7 123 176
41.0 59.0
7,695 300
3.9 27.0 73.0
251
4.7 29.6 70.4 11.0
2:; 33
Table II. Indications Vacuum
extractor
Forceps
Parity i
Indications Prolonged second stage Persistent occipitoposteriof Fetal distress Uterine scar Deep transverse arrest Cardiac disease Toxemia Elderly primipara Bigemini (twins) Chronic lung disease Prolapse of umbilical cord Compound presentation Epilepsy Myopia gravis Imminent rupture of uterus Rupture of sinus marginalis Previous Lash operation Frank breech Partial abruptio placentae Placenta previa marginalis
82 23 35 15 8 6 8 4 2 2 6 1
iii or Total no. I more I of cases
ii
I
10 4 IO 11 1 : 3 1 3 1
7
1; : 2 r T 7
4
T -
-
Prematurity Pulmonary infarct Subcutis
Parity
emphysema 201
Total
Indications
for vacuum
47
extraction
It is generally accepted that the indications for using the vacuum extractor are manifold because it can be used on an incompletely dilated cervix, and in wide variations of levels and positions of the fetal head in the pelvis. While it is true that
52
99 31 60 18 18 16 12 8 9 3 7 6 2 3 2 2 1 1 1 -
i
iii or I more
ii 3 2
62
10 10
14
2
; 11 2 4
1 -
a -
-
T -
5
T
2 1 -
5 2 1
T 300
I
243
1 31
Total
i
of
no. cases
1 3 8 1 8 I 1
85 35 80 11 24 10 8
T
113
T -
94 -
T -
t 6 2 1
26
3 1 -
300
MaImstrom originahy intended the vacuum extractor for improving the contractions of the first stage of labor, present-day usage is much wider, including shortening of the second stage and repositioning of the fetal head. The indications may be either maternal
34
Schenker
May 1, 1967 Am. J. Obst. & Gynec.
and Serr
or fetal and include prolonged second stage, uterine inertia, maternal exhaustion, cardiac or pulmonary complications, severe toxemia, previous uterine scar, fetal distress, and prolapse of the cord. The indications in our cases are summarized in Table II. In cases with more than one indication, only the principal one is mentioned. In 140 (46.6 per cent) casesof vacuum extraction and 155 (51.3 per cent) of forceps delivery, intervention was decided upon because of lack of progress in labor, either from secondary uterine inertia or maternal exhaustion. In 31 ( 10.3 per cent) casesof vacuum extraction and 35 (12.6 per cent) of forceps delivery there was persistent occipitoposterior position of the head, while 18 (6 per cent) casesof vacuum extraction and 24 (8 per cent) of forceps delivery were performed for deep transverse arrest. Fetal distress. Fetal distress was the principal indication in 67 (22.3 per cent) deliveries by the vacuum extractor, 31 of these being in multiparas, where it was impossible to perform forceps delivery because of incomplete dilatation of the cervical OSor the high position of the head in the pelvis. In forceps delivery fetal indications accounted for 89 cases (29.6 per cent), not a signifi-
cantly higher rate than in delivery with the vacuum extractor. Maternal indications. In 35 cases ( 11.6 per cent) of vacuum extraction and 28 (9.3 per cent) of forceps delivery there was a clear-cut reason to prevent undue maternal exertion such as cardiac or pulmonary diseasesor myopia gravis. The use of the extractor in 18 (6 per cent) casesof uterine scar with no case of uterine rupture is worth noting. The state of labor at the time application of the cup
Contractions. In 77 cases (29 per cent), secondary uterine inertia was the outstanding feature, treatment being a combination of intravenous Pitocin infusion and vacuum extraction. Fifty-eight of these patients were primiparas. Cervical dilatation. One of the advantages of the vacuum extractor as opposed to forceps delivery is the possibility of use before complete dilatation of the cervix with the head level high in the pelvis. Dilatation was complete at the start of extraction in 267 cases (89 per cent) ; in the other 33 (11 per cent) dilatation varied from three and a half fingerbreadths to almost complete or dilatation with the anterior lip of the cervix remaining. Most of these latter patients were multiparas. The results are shown in Table III.
Table III. Incomplete dilation of the cervix at the time of application of the cup
) of cases
i
) ii
) iii
) iv
15
5
6
3
)
v
] x
3
1
level
of the head
Table IV summarizes the particulars of the level of the head in the pelvis at the time of application of the vacuum extractor, according to DeLee’s classification.
Parity
No.
of
Table IV. The level of the head at the time of application of the vacuum extractor Level Pelvic Ischial Ischial Ischial Ischial
inlet spines spines spines spines
-2 -1 +1
Total Note:
i
ii
1 4 50 108 38
7
201 One
birth
was a breech
presentation.
:Y 1 47
Parity .. . 111
iv-v
vi-x
xi
6 12 3 1
3 2 6 1 -
1 5 5 2 1
1 1 ! -
6 25 92 135 41
22
12
14
3
299
Total
Volume Number
98 1
In 6 cases (2 per cent) the head was at the level of the pelvic inlet. In 5 of these cases the vacuum extractor was applied because of fetal distress, 2 with prolapse of the cord. The five mothers were multiparas. There was one case of a primipara who was a cardiac patient. In 25 cases (8.3 per cent) the head was at a level higher than the ischial spines, while in 227 (75.5 per cent) the level of the head corresponded to a midforceps application. In only 41 women (13.6 per cent) did the level correspond to a low forcers application. In the 300 forceps deliveries there was no case of high forceps, and in 81 cases (27 per cent) midforceps deliveries were carried out and the rest were low or outlet forceps deliveries.
Abnormal position of the head in the pelvis and other obstetric pathology. The position of the head in the pelvis is important in both vacuum extractor and forceps deliveries. In 31 women with vacuum extractor and 35 with forceps there was persistent occipitoposterior position. The vacuum extractor was used in 8 cases and forceps in 24 for deep transverse arrest. With regard to other obstetric abnormalities, the vacuum extractor was used in 6 cases of compound presentation (including hand alongside head, but excluding in these series prolapse of the cord). There were 9 cases of twinning and in 6 of these the vacuum extractor was applied to the first twin. In one case of breech presentation the extraction was without success. Delivery In 280 cases (93.3 per cent) in which the vacuum extractor was applied, delivery was brought to a successful termination, In 10 cases (3.3 per cent) a start was made with the vacuum extractor when fetal distress developed and the head was still too high for forceps to be applied. The head was brought down with the vacuum extractor and then forceps were applied because of mounting fetal distress. In 5 cases the cup slipped off a number of times (up to a maximum of 3 was allowed) and then the delivery was concluded with forceps. In
Vacuum
extractor
and forceps
35
4 cases with incomplete dilatation of the cervix and the head at a high level in the pelvis, vacuum extraction was attempted because of fetal distress, but was unsuccessful and these women were delivered by cesarean section. Another unsuccessful case was that of a breech presentation. In the forceps deliveries there was no case of so-called failed forceps. Changes in the during extraction
fetal
heartbeat
In 67 cases (22.3 per cent) the indication for vacuum extraction was fetal distress. In some of these, fetal distress increased during extraction and was apparently due to a short umbilical cord or the cord being tight around neck or limbs. In 10 such cases, as noted, the deliveries were concluded with the aid of forceps. Duration
of extraction
The duration of vacuum extraction depends on a number of factors-contractions, cervical dilatation, level and position of the head in the pelvis, and size of the fetus. The patient generally received intravenous Pitocin infusion in order to enhance uterine contractions when necessary, and extraction was more prolonged where the cervix was incompletely dilated or the head was at a high level in the pelvis. Table V gives the number of cases according to the duration of vacuum extraction in minutes. The cases where extraction time was not recorded in the chart are known to be less than 5 minutes. In 158 cases (50.6 per cent), the time of extraction was not more than 5 minutes and in only 4 cases ( 1.3 per cent) reached 20 minutes. In 3 cases (1 per cent) lasting more than 15 minutese, the babies showed central nervous system injury. These 3 represent half the number of cases where application lasted more than 15 minutes (see Table V). Two died of cerebral hemorrhage and another showed signs of transient spasticity and hemorrhagic cerebral spinal fluid.
36
Table
Schenker
May
and Serr
V. Duration
Am.
of traction
I No.
Table
vacuum
l-5
)
Maternal
complications
of
6-10
1
extraction
11-15
92
during
1
25
No.
Complication
16-20
)
20+
Unrecorded
2
4
vacuum
extractor )
%
Postpartum hemorrhage Postpartum fever Thrombophlebitis Cervical laceration Third-degree perineal tear Vaginal and perineal laceration Urethral injury Difficulties in micturition Pulmonary embolism Prolapse of uterus
28 17 3 1 1 3 0 0 0 1
9.3 5.6 1.0 0.3 0.3 1.0 0 0 0 0.3
Total
54
17.8
Anesthesia MalmstrGme claims that in vacuum extraction there is no necessity for general anesthesia except in cases requiring correction of pathologic positions such as version from persistent occipitoposterior, compound presentations, or with the head at a high level in the pelvis. He recommended pudental block or infiltration. Other workers81 g do not use any a nesthesia at all. In our series general anesthesia was employed in 10 cases of combined vacuum extraction and forceps delivery. Pudendal block or infiltration was used in some cases. Of the forceps deliveries 85 per cent were under general anesthesia and the rest under pudendal block. of the genital
in minutes
19
and after delivery With
lacerations
1, 1967 & Gynec.
extractor Time
158
of cases
VI.
with
J. Obst.
tract
All primiparas delivered with forceps had episiotomies. Episiotomy was performed in 204 (68 per cent) of all patients delivered by vacuum extractor. There was one episiotomy which extended to a third-degree perineal tear in both forceps and vacuum extractor deliveries. In one case of vacuum extraction, cervical laceration resulted when
With I
NO.
27 46 5 1 1 27 2 5 1 0 115
force@ I
% 9.0 15.3 1.6 0.3 0.3 9.0 0.6 1.6 0.3 0 38.0
the cup was attached with incomplete dilatation. A few other perineal tears were encountered in vacuum extraction while additional perineal and vaginal tears were found in 27 (9 per cent) cases of forceps delivery. Third
stage
of labor
Twenty-eight women (9.3 per cent) who were delivered by vacuum extractor and 27 (9 per cent) by forceps delivery had postpartum hemorrhage and needed biood transfusions. Manual removal of the placenta was necessary in 7 cases of vacuum extraction (2.5 per cent) and 9 (3 per cent) of forceps delivery. Exploration of the uterine cavity was required in 4 cases of vacuum extractor (1.3 per cent) and 6 (2 per cent) of forceps delivery. Puerperal complications Most authors?? “7 “9 ” claim that puerperal complications following Vacuum extraction are fewer than after forceps delivery. The results in this series are shown in Table VI. Seventeen (5.6 per cent) women after vacuum extraction had postpartum fever of genital tract origin, in com-
Volume 98 Number 1
Table VII.
Vacuum
Birth
of infants vacuum of infants forceps
Table VIII.
(UP to 2,000 12,001-2,500 I2,5OI-3,000
delivered extractor delivered
Perinatal
-
26
36
119
a7
32
8
12
61
128
71
20
2,500
grams
Complications : Cephalhematoma Hypoxia Transient central nervous system injury Intracerebral hemorrhage Severe jaundice Superficial abrasions Fracture of cranium Facial nerve paralysis Erb’s palsy Permanent central nervous system injury Infected cephalhematoma
Forceps I
No.
I
%
45
1.6 1.2
67
26
8.6
20
6:s
12
4.0 2.6 (2 died)
15 14
i:i
8 3 2 11 15
(2 died)
4
1.3
0.6 (2 died) 3.6 5.0
4 5
1.3 (4 died) 1.6
1
0.3
1
0.3
neonate Weight. The weight of the infants in these series was between 1,750 grams and 5,600 grams (Table VII). Complications. The complications have been divided according to their anatomic location-scalp, skull, and central nervous system-as well as being classified as temporary or permanent. One of the transient phenomena in the scalp is the inevitable caput succedaneum of vacuum extraction, the so-called “chignon.” Its size depends on the size of the cup attached to the fetal scalp, and it tends to disappear soon after birth. In 300 deliveries by vacuum extractor 5
g
1.0
-
parison to 46 (15.3 per cent) following forceps delivery; 200 women (66.6 per cent) after forceps delivery received prophylactic antibiotics, as opposed to 146 (48.6 per cent) after vacuum extraction. The
37
complications
Total Perinatal perinatal deaths deaths due to delivery under
forceps
~3,OOZ-.?JOO 13,502-4,000 1 4,001+
Vacuum extractor No. I %
Infants
and
weight
Weight in grams No. by No. by
extractor
12 1 1 1
-
4.0 0.3 0.3 0.3
babies (1.6 per cent) died. Two deaths (0.6 per cent) were directly ascribable to the use of the vacuum extractor, postmortem findings being multiple cerebral hemorrhages. Traction in both these cases continued more than 20 minutes. Two others died during birth from prolapse of the cord and one child died because of a severe congenital cardiovascular defect. Six infants (2 per cent) presented severe asphyxia which responded well to routine resuscitation with or without intubation. The “chignon” on the child’s scalp disappeared in most instances within 24 hours except for 12 (4 per cent) cases with cephalhematoma. A high percentage of babies showed minor lacerations in the area occupied by the cup, but on discharge from the hospital, at an average of five days later, only 15 (5 per cent) still showed signs of erosion in the scalp. Three infants (1 per cent) showed signs of transient central nervous system
38
Schenker and
Serr
damage. One of these had hemorrhagic cerebrospinal fluid, and 2 of them had endured traction for close to 20 minutes. One infant still shows signs of damage to the central nervous system, with marked regression in development. In this case traction was applied with the cervix incompletely dilated and the head still at a high level in the pelvis and was continued for 15 minutes. Eleven infants (3.6 per cent) developed severe jaundice; of these 2 had ABO incompatibility; one had Rh incompatibility; and 5 (1.6 per cent) cases were apparently caused by the cephalhematoma. With regard to birth trauma following forceps delivery, 7 infants died (2.3 per cent) and in 4 (1.3 per cent) of them postmortem findings showed cerebral hemorrhages and tentorial lacerations. Two died at birth from severe asphyxia. Four (1.3 per cent) showed signs of injury to the central nervous system. The percentage of cephalhematomas and superficial abrasions was almost identical to that of vacuum extraction. Facial nerve palsy was recorded in 4 cases, and skull fracture in one. These results are shown in Table VIII. Comment and conclusions The vacuum extractor as an additional obstetric instrument was enthusiastically received in labor wards in many parts of the world”? 11, I31 I4 and in some places was accepted as an almost complete substitute for the forceps. Two publicationP9 I6 enthusiastically reported the vacuum extractor to be rapidly replacing the forceps, but there still occurred polemics in the literature between those who claimed the vacuum extractor will diminish or even replace the use of the forceps, and those who claim that its use is limited to certain specific indications.12’ IT In order to obtain an accurate comparative evaluation of the two instruments it would be necessary to carry out a double blind study, a difficult challenge in clinical obstetric practice and perhaps unjustified. We have, therefore, compared 300 births by vacuum extraction to a similar number
May 1, 1967 Am. J. Obst. & Gynec.
of forceps deliveries. In our two groups the parity, birth weights, and indications for the application of the respective instruments were almost identical. The use of forceps in our Department dropped from 3.9 to 2.4 per cent with the introduction of the vacuum extractor. This low incidence of forceps deliveries, compared to that in common use in the United States is due to our different practice of obstetrics. The vacuum extractor is ‘potentially a substitute for forceps in all cases except for face and breech presentations, and in emergency cases of asphyxia. Its principal advantages over the forceps are the lack of necessity for general anesthesia, the possibility of its use on an incompletely dilated cervix and at a higher level of the head in the peIvis. However, dehvery is much slower than by the use of the forceps and hence the limitation of the vacuum extractor in cases of fetal distress. In 10 of our cases delivery by vacuum extractor was combined with outlet forceps when signs of fetal distress increased. One further advantage is in the correction of pathological vertex positions such as persistent occipitoposterior and deep transverse arrest. Many author+ I8 pointed out that delivery by the vacuum extractor could replace some cases of cesarean section, especially in protracted labor in primiparas, in fetal distress without complete cervical dilatation, or when the head is so high in the pelvis that it precludes forceps delivery. Our experience and our results with the vacuum extractor lead us to the opinion that there is no considerable reduction in the cesarean section rate, contrary to the observations of others.15, I8 The use of vacuum extraction in cases of incomplete dilatation of the cervix or when the head is at a high level in the pelvis is relatively dangerous obstetric procedure, especially to the fetus, although less so than the use of forceps. With respect to the mother, the vacuum extractor is a relatively safe instrument as compared to the forceps. However, whenever the instrument has been applied in in-
Volume
98
Number
1
complete dilatation of the cervix, postpartum inspection of the cervix is obligatory. The danger of ascending infection in the genital tract appears to be minimal (5.6 per cent) as compared to 15.3 per cent in forceps deliveries in this series. With the increased use of the vacuum extractor there have appeared publications emphasizing neonatal lesions.Gl‘II lo, I49lQmZ3 AgiieroZ4 even claimed that of 100 vacuum extractor deliveries all the infants suffered injury except for one. Brey16 showed a rate of neonatal complications in the region of 14.1 per cent in vacuum extraction, Muller,22 19.5 per cent, while our cases show 17.4 per cent. The injury to the infant is directly proportional to the duration of traction and the level of the head in the pelvis at the time of application. Therefore,
Vacuum
extractor
and forceps
39
in keeping with recent opinions, we have concluded that in order to prevent injury to the central nervous system, the vacuum extractor should be used only in caseswith clear-cut obstetric indications, and performed by an experienced obstetrician. The time of traction should not be more than 15 minutes whenever possible. In the event of complications during traction such as changes in the fetal heart rate or lack of progress, delivery should be effected either by forceps or cesarean section. A true evaluation of the advantages of the vacuum extractor in comparison to forceps as regards the infant will be possible only after a follow-up of’ a number of years. Appreciation is expressedto for
reviewing
this
Prof.
Z. Polishuk
manuscript.
REFERENCES
1. Yonge, J.: Cited by Malmstriim, T.: Acta obst. et gynec. scandinav. 36: Suppl. 3, 1957. 2. Finderle, V.: Gynecologia 133: 225, 1952. 3. Finderle, V. : AM. J. OBST. & GYNEC. 69: 1149, 1955. 4. Koller, 0.: Acta obst. et gynec. scandinav. 30: 145, lY50. (Suppl. 7.) 5. Simpson, J. Y.: Edinburgh Monthly J. M. SC. 32: 556, 1849. 6. Malmstram, T.: Acta obst. et gynec. scandinav. 33: Suppl. 4, 1954. I. Malmstrom, T.: Acta obst. et gynec. scandinav. 36: SUDD~. 3. 1957. 8. Bruniquel, 6.: and Israel, A.: GynCc. et obst. 57: 222, 1958. 9. Evelbauer, K.: Geburtsh. u. Frauenh. 19: 188, 1959. M.: Brit. M. J. 1: 165, 1963. 10. Lancet, 11. Mahnstrijm, T.: Acta obst. et gynec. scandinav. 42: Suppl. 1, 1964. 12. Schenker, J. G., and Serr, D. M.: Harefuah 57: 148, 1964. 13. Chalmers, J. A., and Fothergill, R. J.: Brit. M. J. 1: 1684, 1960.
14. 15. 16.
17. 18. 19. 20. 21.
22. 23. 24,
Lange, P.: Acta obst. et gynec. scandinav. 43: Suppl. 1, 53, 1964. Berggrin, 0. G. A.: Acta obst. et gynec. scandinav. 38: 315. 1959. Brey, J., Holtroff; J., Kinzel, W. M., and Schmidt, G.: Geburtsh. u. Frauenh. 22: 550, 1962. Chalmers, J. A., and Fothergill, R. J.: J. Obst. & Gynaec. Brit. Comm. 72: 889, 1965. DSrBler, P.: Med. Klin. 54: 1234, 1959. Boon, W. K.: Lancet 2: 662, 1961. Dessarzin, D., and Bono, S.: Gynecologia 155: 353, 1963. Lehmann, O., Andersson, H., Hansson, G., Malmstrom, T., and Ryba, W.: Acta obst. et gynec. scandinav. 42: 4, 1963. Muller, P., and Fran& R.: Strasbourg med. 11: 563, 1960. Schenker, J. G., and Gombush, G.: Obst. & Gynec. 27: 521, 1966. Agiiero, O., and Alvarez, H.: Obst. & Gynec. 19: 212, 1962.