Cervical Dilator

This invention relates to a cervical dilator.

In the case of overdue delivery owing to an insufficient opening of the cervix which may be caused by insufficient rotation of the fetus' head or by abnormal delivery because of the fetus' size, steps must be taken to effect a delivery which will not injure the mother's body or the fetus by dilating the cervix artificially.

The present methods of dilating the cervix are generally as follows: Hegar's dilator, Bossi's dilator colpeurynter, half colpeurynter, folding type of colpeurynter, metreurynter, dilator of metal spring type, Bougie, and the method of inserting gauze into the cervix.

These methods, however, have little effect in dilating the cervix and are difficult in use. Accordingly, injury to the mother's body and to the fetus often occur.

For example, Bossi's dilator, and the dilator of the metal spring type are apt to injure the cervix of the mother's body. The structure of the colpeurynter and metreurynter types cause difficulty in inserting them into the uterus. In the use of these instruments, the position of the fetus is apt to be changed suddenly from the occipital position to the sacral position, thereby pressing against the fetus' head. Further, in the use of the colpeurynter, it is usual to expand the device by pouring water into it after it is inserted into the uterus and then to pull it by weight at the end of the tube. In this procedure, however, often the device slips off outside of the uterus and dilation of the cervix cannot then be obtained.

This invention relates to a cervical dilator which is used to perform a safe delivery by dilating the cervix either swiftly or slowly as in the case of an over term delivery due to incomplete opening of the uterus in the delivery process which may be caused by weak labor, incomplete rotation of the fetus' head, over term pregnancy, early rupture, early delivery due to the irregular heartbeat of the fetus, or artificial abortion in midterm. This invention can also be applied in veterinary medicine to animals such as cows, pigs and similar animals.

The explanation of drawings in according with the composition of this invention is as follows:

FIG. 1 is a front elevational view of a cervical dilator in accordance with the present invention;

FIG. 2 is a cross sectional view taken along Line 2--2 of FIG. 1, looking in the direction of the arrows;

FIG. 3 is a top plan view looking from the top of FIG. 1;

FIG. 4 is a bottom plan view looking from the bottom of FIG. 1;

FIG. 5 is a side elevational view similar to FIG. 1 showing the expanded form when the cervix is dilated;

FIGS. 6A, 6B, 6C, 6D, 6E, 6F, 6G are isometric views showing preparatory steps prior to using the device;

FIGS. 7 and 8 show the device in use;

FIG. 9 is an isometric view showing the device assembled with other apparatus prior to use;

FIG. 10 is an enlarged, perspective view showing details of end connections;

FIG. 11 is a schematic view showing the change of form of the device under various operating pressures and capacities.

The form of the main body 1 in accordance with this invention is in the general configuration of a mushroom as illustrated in FIG. 1 having a flat head a and a hollow cylindrical stem b. The main body 1 is fabricated of thin rubber or other resilient material into which nets and cloths may be laminated or otherwise affixed for strengthening and shaping purposes as hereinafter more fully set forth. The main body 1 is divided generally into three sections, namely a head a, a stem b and a root section c. The head a terminates in a flat, disc-like surface.

The body 1 may be expanded in a manner similar to that of a rubber tube when pressurized at the inlet 2 of the root section c. Nets and cloths are preferably laminated to or otherwise affixed to the rubber material comprising the body 1 to shape the device to an expected form when pressurized. FIG. 11 shows various shapes which the cervical dilator may assume in accordance with this invention when it is pressurized with a hydraulic pump or otherwise expanded.

A method of affixing the nets in the rubber materials at the time of formation of main body is described as follows.

The nets 3 which may be of rhombic or diamond shape as shown in FIG. 1 are allowed to attain each end of their strings to loop strings 5 which lie along the outer circumstance of head a. The nets extend through the back of head a from the surface of stem b. Said strings extend the length of the stem b from the end 6 to the head a.

The radial nets 4 as shown in FIG. 3 are connected to the and pass side strings 5 passing through the center of head a starting from loop strings 5 which lie around the head a. The radial nets 4' as shown in FIG. 3 and FIG. 4, extend to the vicinity of the center of head a starting from the back of head a alternatively with radial nets 4. Each string is arranged to define approximately equal angles therebetween from the center of head a.

Many of the loop strings 5 as illustrated in FIG. 3 are concentrically arranged and extend from the center of head a to the outer periphery of the head.

At root section c, the cloths 7 are laminated or otherwise affixed to the rubber materials so that said root section c may not be expanded even if pressurized. This part is a composite part with other attachments, and include a pouring tube 10 provided with an air-drain pipe 8 and check valve 9 as shown in FIG. 2.

When said dilator is subjected to hydraulic pressure from a hydraulic pump 13 made of rubber materials (FIG. 9) from pouring tube 10, the root section c is not transformed because of intervention with the cloths 7 in the rubber materials. The stem b and cap c are expanded to a form shown in FIG. 5 because loop strings which form rhombic nets 3 in the back of both b and c, are intervened in the rubber materials. The head a holds the original form. The expansion of rubber materials is controlled by the strain of strings because said cap is composed of radial nets 4 and loop strings 5. In FIGS. 3, 4, 5, 11 shows a rubber band attached to said head of cap a.

As the result of composition as described above, the dilator of cervix according to this invention can be used as follows. When a cervix of pregnant woman who is weak in travail or has a near scheduled delivery, is opened to one finger width, the external labium of said pregnant woman is cleaned and disinfected with chimerosal exposing the vagina with Cusco speculum. The vagina of the pregnant woman is disinfected. The upper and lower portions are held apart with Museux's forcepts and the O. m. is inserted.

As shown in FIG. 6 hold the stem with the right hand FIG. 6A and stretch the top of the head with the other hand and fold the outer surface to the inside to the shape of a finger like (6 - 2) and stretch the small rubber band 11 around the head (FIG. 6c).

Then, said rubber band is pulled holding the base of the rubber band (FIG. 6D) and brought to the condition shown in FIG. 6E by pulling up the rubber band on the top of this device which is folded to elongated configuration as illustrated in FIG. 6F. Said device is inserted into a lower bottom part of the advanced part of fetus as shown in FIG. 7 holding a dressing forceps 12 (FIG. 6G).

A beak tube 14 of a hydraulic pump 13 is inserted into the pouring tube 10 as shown in FIG. 9 and a conduit at the other end of said hydraulic pump is inserted into distillate 15. Then said pump is compressed to discharge the air and water in the device from air-drain pipe 8 and a cork or stop cork 16 is placed to close the drain pipe.

At this time, the rubber band is spontaneously released allowing to expand the slenderly folded head of this device. Approximately 200 c.c of water is poured into the device by compressing said pump. An operator disconnects the beak tube 14 of the rubber pump after confirming whether the device is inserted properly into the cervix, and allows the patient to return to her patient room, and observes her condition for a while. In case no labor occurs then approximaely even after two hours, another 100 c.c of water is poured using said pump so that total amount of water may be about 300 c.c. to 400 c.c. When the cervix is opened by swelling to the condition as shown in FIG. 8, the delivery is near in accordance with higher labor and abdomen pressure.

This invention is, as described above, simple in insertion of the device into the uterus, and injury to the cervix will not occur because the device is made of soft and thin rubber. Further, as the head part of the device is comparatively flat, the head of the fetus is not pressed and is pushed about 2 cm., as the device is expanded. There is no need to pull the main body like a colpeurynter as the back of stem b to cap a is expanded slowly and is allowed to dilate the cervix by the hydraulic pressure from the pump. Further more, this device is designed so that it may be expanded slowly by pressure and amount of water as shown in FIG. 11, and condition of device within the cervix may be conceived by the amount of pouring water, and in addition the dilating rate of cervix may also be controlled in accordance with the condition.

Accordingly, this invention is effective as a device for delivery in lowering the fatigue of not only the fetus and mothers's body but also of midwife reducing the delivery time.