Obstetrical forceps surgery

The operation of applying obstetric forceps is related to the delivery operations. Delivery operations are those by which the delivery is completed. Delivery operations through the natural birth canal include: extraction of the fetus by obstetric forceps, by vacuum extraction, extraction of the fetus by the pelvic ligament, and feticide operations.

The operation of applying forceps is of great importance in obstetrics. Domestic obstetricians have done a great deal to develop and improve this operation, in particular, indications for it and the conditions for its implementation have been developed in detail, their own types of instruments have been created, and the immediate and remote outcomes of the operation for the mother and child have been studied. The role of the obstetrician in providing surgical assistance to women in labor in cases of complicated labor is great and responsible. It is especially great in the operation of applying obstetric forceps. Therefore, among the few, but very important obstetric operations (not counting the easy ones), the operation of applying obstetric forceps undoubtedly occupies a special place both in terms of the relative frequency of its use compared to other obstetric operations, and in terms of the beneficial results that this operation can give with its timely, skillful and careful use.

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Purpose and action of obstetric forceps

The following issues are most frequently discussed in the literature:

1. Are obstetric forceps intended only for the head (including the subsequent one) or can they be applied to the fetus's buttocks;
2. Is it permissible to use forceps to overcome the discrepancy between the sizes of the mother's pelvis and the fetal head, using force and, in particular, the force of attraction or compression of the head with spoons;
3. what is the nature of the extraction force of the forceps;
4. Is it permissible to rotate the head using forceps around its vertical or horizontal axis;
5. Do the pliers have a dynamic action?
6. Should the forceps stretch the soft tissues of the birth canal, preparing them for the cutting of the fetal head?

The first question - about the admissibility of applying forceps to the buttocks - has been resolved positively in domestic obstetrics. Almost all manuals allow the application of forceps to the buttocks, provided that the latter are already firmly driven into the entrance of the small pelvis and it is impossible to insert a finger behind the inguinal fold to extract the fetus. Traction should be done carefully due to the ease with which the forceps slip.

On the second issue - overcoming the mismatch between the fetal head and the mother's pelvis with forceps - domestic obstetricians have a unanimous opinion. Forceps are not intended to overcome the mismatch, and a narrow pelvis in itself is never an indication for surgery. It should be noted that compression of the head by forceps during surgery is inevitable and is an inevitable drawback of the instrument. Back in 1901, in the dissertation work of A. L. Gelfer, changes in intracranial pressure were studied on the corpses of newborns when passing the head with forceps through a narrow pelvis. The author came to the conclusion that when passing the head with forceps through a normal pelvis, intracranial pressure increased by 72-94 mm Hg. Only 1/3 of cases of increased pressure depend on the compressive action of the forceps, and 1/3 - on the compressive action of the pelvic walls. With a true conjugate of 10 cm, intracranial pressure increased to 150 mm, of which 1/3 occurred when forceps were used; with a conjugate of 9 cm, intracranial pressure reached 200 mm, and with 8 cm, even 260 mm Hg.

The most complete substantiation of the view regarding the nature of the extracting force and the possibility of using different types of rotational movements is given by N. N. Fenomyonov. At present, there is a clear position that forceps are intended only for extracting the fetus, and not for artificially changing the position of the head. In this case, the obstetrician follows the movements of the head and assists them, combining the translational and rotational movement of the head, as occurs during spontaneous labor. The dynamic action of the forceps is expressed in increased labor activity when inserting the spoons of the forceps, but this is not of significant importance.

Indications for the application of obstetric forceps

Indications for the operation of application of obstetric forceps are usually divided into indications on the part of the mother and on the part of the fetus. In modern manuals, indications for the operation of application of obstetric forceps are the following: acute distress (suffering) of the fetus and shortening of the second period. There is a significant difference in the frequency of individual indications for the operation. A. V. Lankovits in his monograph "Operation of application of obstetric forceps" (1956) indicates that this difference remains large, even if we do not adhere to the details of the division, and combine the indications into groups: indications on the part of the mother, on the part of the fetus and mixed. Thus, indications on the part of the mother account for 27.9 to 86.5%, and including mixed, from 63.5 to 96.6%. Indications on the part of the fetus vary from 0 to 68.6%, and including mixed, from 12.7 to 72.1%. Many authors do not indicate mixed indications at all. It should be noted that the general formulation of indications given by N. N. Fenomyonov (1907) expresses the general that underlies individual indications and covers the whole variety of particular moments. Thus, N. N. Fenomyonov gave the following general definition of indications for surgery: "The application of forceps is indicated in all cases in which, despite the presence of the necessary conditions for their use, the expulsive forces are insufficient to complete the labor act at the given moment. And further: "If during labor any circumstances arise that threaten the mother or the fetus or both together, and if this danger can be eliminated by the earliest possible completion of labor with the help of forceps, then forceps are indicated." Indications for the application of forceps are a threatening condition of the mother and fetus, requiring, as in the operation of extracting the fetus, an urgent completion of the labor act.

These are: decompensated heart defects, severe lung and kidney diseases, eclampsia, acute infection accompanied by a rise in body temperature, fetal asphyxia. In addition to these general and other obstetric operations, there are special indications for forceps.

1. Weakness of labor activity. The frequency of this indication is significant. The appearance of signs of compression of the soft tissues of the birth canal or the fetus forces one to resort to surgery regardless of the time during which the head was observed standing in the birth canal. However, even without obvious signs of compression of the fetal head and soft tissues of the mother, the obstetrician, if the conditions are present, can resort to surgery on average after 2 hours.
2. Narrow pelvis. For an obstetrician, when conducting labor, it is not the narrow pelvis itself that is important, but the relationship between the size and shape of the mother's pelvis and the fetal head. It should be mentioned that for a long time the purpose and action of forceps was seen as squeezing the head, which facilitates its passage through a narrow pelvis. Subsequently, thanks to the works of domestic authors, especially N. N. Fenomenov, this view of the action of forceps was abandoned. The author wrote: "Speaking out on these grounds in the most categorical way against the doctrine that considers a narrow (flat) pelvis as an indication for forceps, I understand very well, of course, that the application of forceps will nevertheless and should take place with a narrow pelvis, but not for the sake of narrowing, but due to general indications (weakening of labor, etc.), in the presence of the conditions necessary for forceps. After nature, with the help of an appropriate configuration of the head, has smoothed out or almost smoothed out the initial existing discrepancy between the pelvis and the birth object, and when the head has already completely or almost completely passed the narrowed place and for the final birth only requires an increase in the (weakened) pushing activity, which can be replaced artificially, the operation of applying forceps in this case is a completely appropriate aid. Between this view of forceps and a narrow pelvis and the above, there is an enormous and quite obvious difference. Thus, in my opinion, a narrow pelvis in itself can never be considered an indication for an operation of applying forceps. After all, the indication for obstetric operations in general is always the same - it is the impossibility of a voluntary end to labor without danger to the mother and the fetus."
3. Narrowness and inflexibility of the soft tissues of the birth canal and their strangulation - these indications are extremely rare.
4. Unusual insertions of the head. Unusual insertion of the head cannot be an indication for surgery if it is a manifestation of pelvic-head discrepancy and this discrepancy is not overcome. Forceps should not be used to correct the position of the head.
5. Threatened and accomplished rupture of the uterus. At present, only N. A. Tsovyanov considers overstretching of the lower segment of the uterus among the indications for the application of forceps. A. V. Lankovits (1956) believes that if the head is in the pelvic cavity or even more so at its outlet, then in such cases a cesarean section is impossible, and the spoons of the forceps cannot have direct contact with the uterus, since the cervix has already moved beyond the head. The author believes that in such a situation and the threat of rupture of the uterus, there are grounds to consider the operation of applying cavity and outlet forceps indicated. It is quite obvious that refusing vaginal delivery in the case of a diagnosed rupture of the uterus during labor is the only correct position of the doctor.
6. Bleeding during childbirth is only in exceptional cases an indication for forceps surgery.
7. Eclampsia is an indication for forceps delivery quite often, from 2.8 to 46%.
8. Endometritis during childbirth. A. V. Lankovits, based on observations of 1000 births complicated by endometritis, believes that only if attempts to accelerate the course of labor by conservative measures are unsuccessful or if any other serious indications appear on the part of the mother or fetus is surgery permissible.
9. Cardiovascular diseases - the issue should be resolved individually, taking into account the clinical picture of the extragenital disease, together with a therapist.
10. Respiratory diseases - a functional assessment of the mother's condition is taken into account, with determination of the external respiration function.
11. Intrauterine fetal asphyxia. When signs of incipient asphyxia appear and are not amenable to conservative treatment, immediate delivery is indicated.

Conditions necessary for the application of obstetric forceps

To perform a forceps delivery, a number of conditions are necessary to ensure a favorable outcome for both the mother and the fetus:

1. The presence of the head in the cavity or outlet of the pelvis. If this condition is present, all the others are usually present. The operation of applying forceps with a high standing head refers to the so-called high forceps and is not currently used. However, obstetricians still mean completely different operations by high forceps. Some mean by high forceps the operation of applying them to the head, which has settled with a large segment at the entrance to the small pelvis, but has not yet passed the terminal plane, others mean an operation when the head is pressed to the entrance, and still others - when the head is mobile. By high forceps he means such an application when the largest segment of the head, being tightly fixed at the entrance to the small pelvis, has not yet had time to pass the terminal plane. In addition, it is quite right to note that determining the height of the head in the pelvis is not as simple as it may seem at first glance. None of the proposed methods for determining the height of the head in the pelvis (fulfillment of the sacral cavity, the posterior surface of the pubis, accessibility of the promontory, etc.) can claim to be accurate, since this determination can be influenced by various factors, namely: the size of the head, the degree and shape of its configuration, the height and deformation of the pelvis and a number of other circumstances that are not always amenable to consideration.

Therefore, it is not the head in general that is important, but its greatest circumference. Moreover, the greatest circumference of the head does not always pass through the same section of the head, but is associated with the peculiarity of insertion. Thus, with occipital insertion, the greatest circumference will pass through the small oblique size, with parietal (anterior-head) insertion - through the straight, with frontal - through the large oblique and with facial - through the vertical. However, with all these types of head insertion, it will be practically correct to consider that its greatest circumference passes at the level of the ears. By moving a half-hand (all fingers except the thumb) high enough during a vaginal examination, you can easily find both the ear and the innominate line, which forms the border of the entrance to the pelvis. Therefore, it is recommended to conduct an examination before surgery with a half-hand, and not with two fingers, in order to reach the ear and determine with absolute accuracy in which plane of the pelvis the greatest circumference of the head is located and how it is inserted.

Below are the options for the position of the head in relation to the planes of the small pelvis (Martius diagram), which should be taken into account when applying obstetric forceps:

• Option 1 - the fetal head is above the entrance to the small pelvis, application of forceps is impossible;
• Option 2 - the fetal head is in a small segment at the entrance to the small pelvis, the application of forceps is contraindicated;
• Option 3 - the fetal head with a large segment at the entrance to the small pelvis, the application of forceps corresponds to the high forceps technique. This technique is not currently used, since other methods of delivery (vacuum extraction of the fetus, cesarean section) give more favorable results for the fetus;
• Option 4 - the fetal head is in the wide part of the pelvic cavity, cavity forceps can be applied, however, the technique of the operation is very complex and requires a highly qualified obstetrician; 
• Option 5 - the fetal head is in the narrow part of the pelvic cavity, cavity forceps can be applied;
• Option 6 - the fetal head is in the plane of exit from the pelvis, the best position for applying obstetric forceps using the exit forceps technique.

The question of where the lower pole of the head is located plays a completely secondary role, since with different insertions the lower pole of the head will be located at different heights; with the configuration of the head the lower pole will be lower. Of great importance is the mobility or immobility of the fetal head. Complete immobility of the head usually occurs only when its largest circumference coincides or almost coincides with the plane of entry.

2. Correspondence between the sizes of the mother's pelvis and the fetus's head.
3. Average head size, i.e. the head of the fetus should not be too large or too small.
4. Typical insertion of the head - forceps are used to extract the fetus and therefore should not be used to change the position of the head.
5. Complete dilation of the cervical os, when the edges of the os have moved beyond the head everywhere.
6. A ruptured amniotic sac is an absolutely necessary condition.
7. Living fruit.
8. Precise knowledge of the location of the presenting part, position, including the degree of asynclitism.
9. The lower pole of the head is at the level of the ischial spines. It should be noted that a pronounced birth swelling can mask the true position of the head.
10. Sufficient dimensions of the pelvic outlet - lin. intertubero more than 8 cm.
11. Sufficient episiotomy.
12. Adequate anesthesia (pudendal, paracervical, etc.).
13. Emptying the bladder.

Without dwelling on the technique of applying obstetric forceps, which is covered in all manuals, it is necessary to dwell on the positive and negative aspects of applying forceps for both the mother and the fetus. At present, however, there have been isolated works on the comparative assessment of the use of obstetric forceps and a vacuum extractor.

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Models of obstetric forceps

Forceps are an obstetric instrument used to extract a live, full-term or nearly full-term fetus from the birth canal by the head.

There are over 600 different models of obstetric forceps (French, English, German, Russian). They differ mainly in the design of the spoons of the forceps and the lock. Levre forceps (French) have long intersecting branches, a rigid lock. Naegele forceps (German) - short intersecting branches, the lock resembles scissors: the left spoon has a rod in the form of a cap, the right - a notch that fits the rod. Lazarevich forceps (Russian) have non-intersecting (parallel) spoons with only a head curvature and a movable lock.

Recently, most obstetricians have been using the Simpson-Phenomenov (English) model of forceps: the crossing spoons have two curvatures - head and pelvic, the lock is semi-movable, and the handle of the forceps has lateral projections - Bush hooks.

General rules for applying obstetric forceps

To perform the operation, the woman in labor is placed on a Rachmanov bed in the position for vaginal operations. Before the operation, the bladder is catheterized and the external genitalia are treated. The operation of applying obstetric forceps is performed under general anesthesia or epidural anesthesia. An episiotomy is usually performed before the operation.

The main points of the operation of applying obstetric forceps are the introduction of the forceps spoons, closing the forceps, performing traction (test and working), and removing the forceps.

The main principles that must be observed when applying obstetric forceps are dictated by three rules.

1. The first triple howl concerns the insertion of the branches (spoons) of the forceps. They are inserted into the genital tract separately: the first inserts the left spoon with the left hand into the left half of the pelvis ("three from the left") under the control of the right hand, the second inserts the right spoon with the right hand into the right half of the pelvis ("three from the right") under the control of the left hand.
2. The second triple rule is that when the forceps are closed, the axis of the forceps, the axis of the head, and the pelvic axis (the "three axes") must coincide. To do this, the forceps should be applied so that the tops of the spoons are facing the fetal head axis, grasp the head along the largest circumference, and the head axis is in the plane of the forceps axis. When the forceps are applied correctly, the fetal ears are between the spoons of the forceps.
3. The third triple rule reflects the direction of traction when extracting the head with forceps depending on the position of the head ("three positions - three tractions"). In the first position, the fetal head is located with a large segment in the plane of the entrance to the small pelvis, and the tractions are directed from top to bottom (towards the toes of the shoes of the sitting obstetrician). Extraction of the fetal head located in the entrance to the small pelvis using obstetric forceps (high forceps) is not currently used. In the second position, the fetal head is in the cavity of the small pelvis (cavity forceps), and the tractions are performed parallel to the horizontal line (in the direction of the knees of the sitting obstetrician). In the third position, the head is in the plane of exit from the small pelvis (exit forceps), the tractions are directed from bottom to top (to the face, and at the last moment - in the direction of the forehead of the sitting obstetrician).

Technique of application of obstetric forceps

The exit forceps are applied to the fetal head located in the plane of exit from the small pelvis. In this case, the sagittal suture is located in the direct dimension of the exit plane, the forceps are applied in the transverse dimension of this plane.

The insertion of the forceps spoons is carried out according to the first triple rule, the closing of the forceps according to the second triple rule. The forceps spoons are closed only if they lie correctly. If the spoons do not lie in one plane, then, by pressing on the Bush hooks, the spoons must be turned into one plane and closed. If it is impossible to close the forceps, the spoons must be removed and the forceps applied again. 

After the closure of the tenons, traction is performed. First, to check the correct application of the forceps, I perform a trial traction. To do this, grasp the handle of the forceps from above with the right hand so that the index and middle fingers of the right hand lie on the Bush hooks. Place the left hand on top of the right so that the index finger touches the fetal head. If the forceps are applied correctly, then during the trial traction, the head moves behind the forceps.

If the forceps are not applied correctly, the index finger moves away from the fetal head together with the forceps (forceps slippage). A distinction is made between vertical and horizontal slippage. In the case of vertical slippage, the tips of the forceps spoons diverge, slide along the head and come out of the genital tract. In the case of horizontal slippage, the forceps slide from the head upwards (towards the womb) or backwards (towards the sacrum). Such slippage is only possible with a high positioned head. At the first signs of forceps slippage, the operation should be stopped immediately, the forceps spoons should be removed and reinserted.

Working tractions (tractions proper) are performed after the success of the trial traction is confirmed. The right hand remains on the forceps, and the left hand grasps the handles of the forceps from below. The direction of the tractions corresponds to the third triple rule - first to the face, then to the forehead of the sitting obstetrician. The force of the tractions resembles pushing - gradually increasing and gradually weakening. Like pushing, tractions are performed with pauses, during which it is useful to relax the forceps to avoid excessive compression of the head.

After the fetus's occiput appears above the perineum, the obstetrician should stand to the side of the woman in labor, grasp the handles of the forceps with his hands and direct the traction upwards. After the head has emerged, the traction is directed upwards with one hand, while the perineum is supported with the other.

After extracting the largest perimeter of the fetal head, the forceps are removed in reverse order (first the right spoon, then the left). After this, the fetal head and shoulders are removed manually. 

Technique of application of exit (typical) obstetric forceps in case of posterior occipital presentation

In the case of a posterior occipital presentation, the forceps are applied in the same way as in the anterior presentation, but the nature of the traction in this case is different. The first tractions are directed steeply downwards until the area of the large fontanelle is brought under the pubic symphysis, then the crown is brought out by upward traction.

After the back of the head appears above the perineum, the handles of the forceps are lowered down, the fetus's head straightens and its facial part appears in the genital slit.

Technique of application of cavity (atypical) obstetric forceps

The cavity forceps are applied to the fetal head located in the pelvic cavity. In this case, the sagittal suture is located in one of the oblique dimensions (right or left) of the pelvis, the forceps are applied in the opposite oblique dimension of this plane. In the first position (sagittal suture in the right oblique dimension), the forceps are applied in the left oblique dimension, in the second position (sagittal suture in the left oblique dimension) - in the right oblique dimension (Fig. 109).

The insertion of the forceps spoons is carried out according to the first triple rule ("three on the left, three on the right"), but in order for the forceps spoons to lie in the oblique dimension of the pelvis, one of the spoons must be shifted upwards (towards the pubis). The spoon that does not shift after insertion into the pelvic cavity is called fixed. The spoon that shifts towards the pubis is called wandering. In each individual case, depending on the location of the sagittal suture, either the right or the left spoon will be fixed. In the first position (sagittal suture in the right oblique dimension), the fixed spoon will be the left one, in the second position (sagittal suture in the left oblique dimension), the right one.

The closure of the forceps, trial and working tractions are carried out according to the rules described above.

In addition to complications associated with improper surgical technique, ruptures of the perineum, vagina, labia majora and minora, and clitoris may occur. Urination and defecation disorders are possible in the postpartum period.

The operation can also be traumatic for the fetus: damage to the soft tissues of the head, cephalohematoma, retinal hemorrhage, impaired cerebral circulation, and trauma to the bones of the skull.

The operation of applying obstetric forceps to this day remains a rather traumatic method of operative delivery through the natural birth canal. The outcome of labor for the fetus largely depends on its body weight, the height of the head, the position of the head, the duration of the operation, the qualifications of the doctor, the condition of the fetus at the beginning of the operation and the quality of neonatal care.

Contraindications to the application of forceps

• stillbirth;
• hydrocephalus;
• facial or frontal insertion;
• incomplete dilation of the cervical os;
• the position of the presenting part is unclear.

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Complications of obstetric forceps delivery

In domestic and foreign literature, attention is drawn to a number of complications in the mother and fetus during the operation of applying obstetric forceps. Particular attention is paid to the increase in the number of cephalohematomas by 3-4 times during the application of obstetric forceps. When analyzing 5,000 births, it was found that during spontaneous births, cephalohematoma is observed in 1.7% versus 3.5% during the operation of applying exit obstetric forceps and in 32.7% during cavity obstetric forceps. Despite the fact that in these observations no pathological electroencephalograms or skull damage were found, cephalohematomas were found in 25% of studies, and the authors associate skull damage with the use of obstetric forceps. Although cephalohemogomas quickly pass, it should be noted that neonatal complications are not uncommon, including complications of this neonatal period such as anemia, hyperbilirubinemia, calcification, septicemia and meningitis. Thus, the immediate outcomes of the forceps operation for a child can be considered by dividing all complications into the following types:

• soft tissue damage;
• hemorrhages in the brain and cranial cavity;
• asphyxia;
• rare injuries to the bones of the skull, eyes, nerves, collarbone, etc.

No increase in perinatal morbidity and mortality has been found with exit obstetric forceps. With regard to cavity forceps, the issue remains unclear to this day. Some authors believe that the decrease in perinatal morbidity and mortality is associated with the wider use of cesarean section, and obstetric forceps are suggested only for difficult births.

In conclusion, it can be said with full justification that even Russian-type pliers - the most advanced of all types of this instrument - do not represent a completely safe tool and should not be used without sufficient grounds.

An obstetrician can follow this only correct path only under the condition of good organization of obstetric care, creative development of the heritage of the Russian obstetric school, continuous improvement of his knowledge and experience, thoughtful clinical assessment of the entire body of the woman giving birth. The difficulties of such a path are not small, but quite surmountable.

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