METREURYSIS

METREURYSIS, a method of artificial, non-bloody induction of labor (accouchement force). The essence of M. consists in introducing into the uterus a special instrument which partly mechanically stretches it, and partly through mechanical irritation causes its active contractions. A metreurysmeter is an instrument that causes such irritation and stretching of the uterus; in appearance it is almost identical with a colpeurynter; the difference is that the colpeurynter is inserted only into the vagina, whereas the metreurysmeter is inserted directly into the cervix and further into its lower segment. The production of artificial dilation of the cervix has long been one of the responsible obstetric operations, especially when considering the high morbidity of mothers and significant mortality of children which it entails. The first to propose this method of dilation was Braun (1851), but he inserted only a water-filled rubber balloon into the vagina. Madurowicz (1864) used a balloon once in the interest of the fetus in cases of placenta praevia. Only since 1883 has this method gained general acceptance, since Schauta began to use it widely, inserting the instrument already into the uterus; initially this metreurysmeter had the appearance of an hourglass-shaped rubber bag; later it underwent various modifications; at the same time the indications for its use increasingly expanded. At present there are three types of these instruments: one-the aforementioned one, but somewhat modified by Fehling, the biscuit-shaped Barnes-Fehling metreurysmeter, the second-conical by Champetier de Ribes, and the third-ordinary pear-shaped-by Braun. Method of application of M. The instrument is boiled for half an hour in water and cooled; then the vaginal part of the cervix is exposed with specula, wiped with a cloth soaked in an antiseptic solution, and fixed with bullet forceps; after this the metreurysmeter is grasped with special forceps (Metreurynter-Zange) in such a way that its tip protrudes 1-1½ cm from them, is rolled up like a cigar, and is carefully advanced through the internal os (when rolling up, the air from the tube of course is squeezed out). Before using the instrument, its integrity must be checked; when two-thirds of it are already in the uterus, it is held with the fingers of the left hand, and the forceps are removed with the right; then it is filled with sterile water or sterile saline solution (in case of possible rupture) and clamped with a tap or clamps. The amount of liquid introduced at once should not exceed 300-400 cm³. Subsequently it is necessary to watch for the onset of labor activity, controlling the metreurysmeter by gently pulling on its end, so as not to miss the moment for adding solution, because otherwise the instrument will exit into the vagina before the necessary dilation of the cervix occurs. The filling of M. must be done slowly, as shock may occur (according to Meyer's opinion, on the basis of excessively rapid stretching of the uterus). For faster dilation of the os, a weight can be suspended to the instrument, passed over the foot end of the bed, and then either wait for the spontaneous exit of the metreurysmeter or gradually and carefully pull it. The weight should not exceed by more than 100 g the weight of the liquid introduced; an excess of it can lead to rupture of the cervix, which is observed in 12% of cases. In rare cases, part of the cervix is torn off even without suspending a weight (Selitsky) (see figure). If contractions have significantly intensified, the suspended weight should be reduced. The introduction of the metreurysmeter is possible with the cervix dilated to 1-1½ fingers; in case of no dilation, it is necessary to perform preliminary dilation of the cervix using Hegar dilators. The metreurysmeter is introduced extra- or intraamniotically and usually without anesthesia. The uterine contractions caused by the metreurysmeter probably occur due to mechanical irritation of the nerve nodes of the cervix. Metreuryxis as a method of artificial induction of labor is used: 1) for mechanical dilation of the cervix in cases of delayed dilation and early rupture of membranes; 2) for inducing artificial premature labor; 3) in cases of cord presentation when a version is planned, but there is not yet the necessary dilation for this operation; 4) in transverse position when membranes have ruptured with minimal dilation; 5) to preserve as much amniotic fluid as possible and strengthen contractions in premature rupture of the membranes; 6) in cases of placenta previa, especially in conditions of district work, when a major operation for some reason cannot be performed for technical reasons or local conditions; in placenta praevia the metreurysmeter pursues two goals: it serves as a mechanical irritant promoting dilation of the cervical canal, and at the same time it compresses the bleeding surface; 7) for reduction of an incarcerated pregnant uterus; the use of the metreurysmeter due to its gradual and uniform action is a more gentle measure here than manual reduction. In gynecological diseases it can be used for correction of a retroverted mobile uterus, as well as for stretching adhesions in a retroverted fixed uterus; then as a combined abdominal-vaginal method of regulating intra-abdominal pressure, significantly altered after removal of a very large tumor; this is achieved by applying a certain weight to the abdomen and introducing a balloon weighing 1-1½ kg, pressed directly against the cervix. Such mechanical pressure together with counter-pressure is at the same time a hemostatic agent preventing hematoma formation in cases where there is suspicion of insufficient hemostasis. In general M. is easily performed and not technically complicated, but it has its negative sides, namely: 1) it is not always reliable: in some cases, even with prolonged use, the effect does not occur, i.e., the cervix does not stretch, and the balloon, even if repeatedly introduced, exits into the vagina; in others, repeated introduction of larger balloons is required to ensure continuous labor activity, because often labor activity, which has occurred quite quickly and moreover strongly, soon ceases, and the balloon is found lying freely in the vagina (therefore it is necessary to have several pieces of different sizes). 2) M. is more effective in multiparas than in primiparas, which is explained of course by the greater elasticity of the uterine cervix in the former. The average duration of its action is about 14 hours (Pobedinsky). 3) Its effect varies depending on the amount of liquid introduced: in some cases insufficient stretching of the entire instrument is obtained, and in others (with excess liquid) its rupture may occur. 4) M. is not always a reliable hemostatic method, because soft balloons do not press the detached placenta tightly enough, while hard ones do not come into close contact with the uterine wall, due to which a free space remains and bleeding continues. 5) The percentage of fetal mortality with the use of the metreurysmeter according to some authors reaches 40. 6) The percentage of maternal morbidity is also comparatively large-up to 12. 7) Due to the long and often unsuccessful stay (sometimes more than 10 hours, and counting repeated introductions, even several days) of the metreurysmeter in the uterus, not to mention the moment of its passage through the birth canal, infection is of course always possible; therefore to accelerate labor activity, sometimes the metreurysmeter has to be combined with the administration of pituitrin. 8) In dangerous diseases threatening the life of the patient (severe diseases of the heart, lungs, kidneys), requiring rapid but at the same time gentle delivery (e.g., eclampsia), M. is contraindicated (especially in primiparas; Selitsky).

Circular tear of the cervix.

In cases where the cervix is not sufficiently dilated, preliminary dilation using Hegar dilators is necessary. The metreurysmeter can be introduced extra- or intraamniotically and usually without anesthesia. Uterine contractions caused by the metreurysmeter probably occur due to mechanical irritation of the nerve nodes of the cervix. Metreuryxis as a method of artificial induction of labor is used: 1) for mechanical dilation of the cervix in cases of delayed dilation and early rupture of membranes; 2) for inducing artificial premature labor; 3) in cases of cord presentation when a version is planned, but there is not yet the necessary dilation for this operation; 4) in transverse position when membranes have ruptured with minimal dilation; 5) to preserve as much amniotic fluid as possible and strengthen contractions in premature rupture of the membranes; 6) in cases of placenta previa, especially in conditions of district work, when a major operation for some reason cannot be performed for technical reasons or local conditions; in placenta praevia the metreurysmeter pursues two goals: it serves as a mechanical irritant promoting dilation of the cervical canal, and at the same time it compresses the bleeding surface; 7) for reduction of an incarcerated pregnant uterus; the use of the metreurysmeter due to its gradual and uniform action is a more gentle measure here than manual reduction. In gynecological diseases it can be used for correction of a retroverted mobile uterus, as well as for stretching adhesions in a retroverted fixed uterus; then as a combined abdominal-vaginal method of regulating intra-abdominal pressure, significantly altered after removal of a very large tumor; this is achieved by applying a certain weight to the abdomen and introducing a balloon weighing 1-1½ kg, pressed directly against the cervix. Such mechanical pressure together with counter-pressure is at the same time a hemostatic agent preventing hematoma formation in cases where there is suspicion of insufficient hemostasis. In general M. is easily performed and not technically complicated, but it has its negative sides, namely: 1) it is not always reliable: in some cases, even with prolonged use, the effect does not occur, i.e., the cervix does not stretch, and the balloon, even if repeatedly introduced, exits into the vagina; in others, repeated introduction of larger balloons is required to ensure continuous labor activity, because often labor activity, which has occurred quite quickly and moreover strongly, soon ceases, and the balloon is found lying freely in the vagina (therefore it is necessary to have several pieces of different sizes). 2) M. is more effective in multiparas than in primiparas, which is explained of course by the greater elasticity of the uterine cervix in the former. The average duration of its action is about 14 hours (Pobedinsky). 3) Its effect varies depending on the amount of liquid introduced: in some cases insufficient stretching of the entire instrument is obtained, and in others (with excess liquid) its rupture may occur. 4) M. is not always a reliable hemostatic method, because soft balloons do not press the detached placenta tightly enough, while hard ones do not come into close contact with the uterine wall, due to which a free space remains and bleeding continues. 5) The percentage of fetal mortality with the use of the metreurysmeter according to some authors reaches 40. 6) The percentage of maternal morbidity is also comparatively large-up to 12. 7) Due to the long and often unsuccessful stay (sometimes more than 10 hours, and counting repeated introductions, even several days) of the metreurysmeter in the uterus, not to mention the moment of its passage through the birth canal, infection is of course always possible; therefore to accelerate labor activity, sometimes the metreurysmeter has to be combined with the administration of pituitrin. 8) In dangerous diseases threatening the life of the patient (severe diseases of the heart, lungs, kidneys), requiring rapid but at the same time gentle delivery (e.g., eclampsia), M. is contraindicated (especially in primiparas; Selitsky).

In general M. is easily performed and not technically complicated, but it has its negative sides, namely: 1) it is not always reliable: in some cases, even with prolonged use, the effect does not occur, i.e., the cervix does not stretch, and the balloon, even if repeatedly introduced, exits into the vagina; in others, repeated introduction of larger balloons is required to ensure continuous labor activity, because often labor activity, which has occurred quite quickly and moreover strongly, soon ceases, and the balloon is found lying freely in the vagina (therefore it is necessary to have several pieces of different sizes). 2) M. is more effective in multiparas than in primiparas, which is explained of course by the greater elasticity of the uterine cervix in the former. The average duration of its action is about 14 hours (Pobedinsky). 3) Its effect varies depending on the amount of liquid introduced: in some cases insufficient stretching of the entire instrument is obtained, and in others (with excess liquid) its rupture may occur. 4) M. is not always a reliable hemostatic method, because soft balloons do not press the detached placenta tightly enough, while hard ones do not come into close contact with the uterine wall, due to which a free space remains and bleeding continues. 5) The percentage of fetal mortality with the use of the metreurysmeter according to some authors reaches 40. 6) The percentage of maternal morbidity is also comparatively large-up to 12. 7) Due to the long and often unsuccessful stay (sometimes more than 10 hours, and counting repeated introductions, even several days) of the metreurysmeter in the uterus, not to mention the moment of its passage through the birth canal, infection is of course always possible; therefore to accelerate labor activity, sometimes the metreurysmeter has to be combined with the administration of pituitrin. 8) In dangerous diseases threatening the life of the patient (severe diseases of the heart, lungs, kidneys), requiring rapid but at the same time gentle delivery (e.g., eclampsia), M. is contraindicated (especially in primiparas; Selitsky).