WO2001003590A1

WO2001003590A1 - Obstetrical vacuum extractor cup

Info

Publication number: WO2001003590A1
Application number: PCT/US2000/018562
Authority: WO
Inventors: Dan G. Dimitriu; Jerry D. Hulse
Original assignee: Prism Enterprises, Inc.
Priority date: 1999-07-09
Filing date: 2000-07-06
Publication date: 2001-01-18
Also published as: AU5788100A

Abstract

An obstetrical vacuum extractor (10) for placement on a child's head for use during childbirth is provided. The vacuum extractor (10) includes a vacuum cup (12) having a side wall (20) defining a hollow interior cavity. The side wall (20) has a side wall edge that defines a cup opening. The vacuum cup (12) further includes a vacuum opening (28) in communication with the interior cavity of the cup (12) which is adapted for connection to a vacuum source. A plurality of axially spaced annular force distribution ridges (38a, 38b) are arranged on the side wall of the vacuum cup (12) to contact and form a seal with the child's head and thereby increase the surface area over which the forces which result from operation of the extractor are distributed.

Description

OBSTETRICAL VACUUM EXTRACTOR CUP

FIELD OF THE INVENTION The present invention relates to an apparatus for facilitating the delivery of a child during childbirth, and more specifically relates to vacuum extractors for use during childbirth.

BACKGROUND OF THE INVENTION Often, during childbirth, the birth mother cannot deliver the child without assistance from an attending physician. In some cases, all that is required is for the attending physician or other medical personnel to push down on the birth mother's upper abdomen when she bears down during delivery. In other cases, it is necessary for a physician to perform a cesarean section. However, for those cases which fall between those two extremes, some sort of intermediate assistance is often required. This typically entails the use of some type of medical device to aid the mother in the delivery of the child. In some circumstances, these devices may also be used to assist a physician during particularly difficult cesarean sections. Forceps or other similar devices are one type of device which can be used by a physician to assist a mother during childbirth. Forceps, however, tend to be bulky and difficult for the physician to operate. Moreover, the use of forceps, at the very least, is uncomfortable for the mother and child and risks injury to both.

An alternative device which can be used to assist a mother during childbirth is a vacuum extractor. A vacuum extractor generally includes a cup, which is placed onto the child's head. A manipulation device of some sort is coupled to the cup. For example, an elongated hollow stem may be connected to the cup by which the cup may be positioned onto the child's head and through which vacuum pressure is introduced into the cup. Alternately, a chain or traction cord may be provided, and a vacuum introduced through a vacuum stem extending outward from the cup. The introduction of vacuum pressure into the cup results in a suction force being applied between the cup and the child's head which adheres the cup to the child's head. Once the cup is positioned on and adhered to the head of the child, the vacuum extractor can then be used to extract the child from the birth canal by manipulating the traction cord, or some sort of handle or other gripping device coupled to the stem of the vacuum extractor. Several different types of vacuum extractors are known such as those described in U.S. Patent Nos. 3,202,152, 5,019,086, 5,163,944 and 5,281,229 and U.S. Application Serial No. 08/853,422. Although vacuum extractor devices are widely used, the edge of the cup, which forms the seal between the cup and the child's head, defines a relatively small contact surface through which the forces which result from operation and manipulation of the extractor are transmitted to the child's head. Since the contact surface between the cup and the child's head is relatively small, the resultant forces caused by operation of the extractor are concentrated over a corresponding relatively small area of the child's scalp. As will be appreciated, this increases the potential for an injury to the child as compared to if the forces were distributed over a greater area of the child's head.

One way in which to minimize this potential problem is by lining the cup with a second cup formed of a soft, pliable material, which, when assembled, wraps around the edge of the cup thus providing a soft, relatively friendly contact with the child's head. While this vacuum extractor design reduces the possibility abrasion or other similar injuries to maternal tissues and the child by cushioning the contact between the vacuum extractor cup and the adjacent tissue, it does not significantly increase the area over which the forces resulting from operation of the vacuum extractor are applied to the child's head. Accordingly, it is desirable to more evenly distribute the vacuum forces applied to the child's head in order to further reduce the potential for injuries to the child.

In U.S. Patent 5,713,909, Lindsey discloses a vacuum extractor utilizing a soft, flexible sleeve which extends radially inward over the open end of the cup. Lindsey asserts that this sleeve provides a greater surface area for contacting the child's head. It will be appreciated, however, that it appears that the radially inwardly extending sleeve would not likely remain flat on the infant's head when an extraction force is applied. U.S. Patent 5,693,058 to Cavanagh discloses a vacuum cup having an internal integral skirt. These sleeves or skirts, however, either do not effectively distribute the forces and/or they are difficult to mold (and assemble in the case of Lindsey), thereby increasing the manufacturing costs associated with the vacuum extractor without a corresponding increase in comfort.

OBJECTS AND SUMMARY OF THE INVENTION Accordingly, in view of the foregoing, it is a general object of the invention to provide a vacuum extractor which reduces the potential of injury caused by contact of the extractor with the child's head.

A more specific object of the present invention is to provide a vacuum extractor having a cup which distributes the forces which result from the operation of the extractor over a greater area of the fetal scalp thereby reducing the potential for a concentration of forces which can lead to injury to the child. Another object of the present invention is to provide a vacuum extractor as characterized above which has a design that is economical to produce in that it can be manufactured in a cost efficient manner. The present invention provides these and other advantages and overcomes the drawbacks of the prior art by providing an obstetrical vacuum extractor for placement on a child's head for use during childbirth which substantially increases the contact sealing surface between the extractor and the child's head. The vacuum extractor includes a vacuum cup having a side wall defining a hollow interior cavity. The side wall has a side wall edge that defines a cup opening and the vacuum cup further includes a vacuum opening in communication with the interior cavity of the cup which is adapted for connection to a vacuum source. A plurality of axially spaced annular force distribution ridges are arranged on the inside surface of the side wall of the vacuum cup. The force distribution ridges are arranged to contact and form a seal with the child's head and thereby increase the surface area over which the forces which result from operation of the extractor are distributed to the child's head. A handle is also coupled to the vacuum cup to allow for manipulation of the extractor.

These and other features and advantages of the invention will be more readily apparent upon reading the following description of a preferred exemplary embodiment of the invention and upon reference to the accompanying drawings wherein:

BRIEF DESCRDPTION OF THE DRAWINGS FIGURE 1 is a partially cut away side elevational view of an illustrative obstetrical vacuum extractor constructed in accordance with teachings of the present invention.

FIG. 2 is an enlarged fragmentary side sectional view of the cup of the illustrative vacuum extractor of FIG. 1 showing the force distribution ridges. FIG. 3 is a plan view of the distal end of the illustrative vacuum extractor of FIG. 1.

FIG. 4 is a side sectional view of the cup of an alternative embodiment of the vacuum extractor of the present invention.

FIG. 5 is a cross-sectional, elevational view of a third embodiment of an obstetrical vacuum extractor constructed in accordance with teachings of the invention.

FIG. 6 is an enlarged fragmentary view of the obstetrical vacuum extractor cup of FIG. 5.

FIG. 7 is an elevational view of a fourth embodiment of an obstetrical vacuum extractor constructed in accordance with teachings of the invention, and partially broken away in the cup area.

FIG. 8 is a bottom view of the obstetrical vacuum extractor cup of FIG. 7. FIG. 9 is a fragmentary, cross-sectional, elevational view of a fifth embodiment of an obstetrical vacuum extractor cup constructed in accordance with teachings of the invention. While the invention will be described and disclosed in connection with certain preferred embodiments and procedures, it is not intended to limit the invention to those specific embodiments. Rather it is intended to cover all such alternative embodiments and modifications as fall within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now more particularly to FIG. 1 of the drawings, there is shown an illustrative obstetrical vacuum extractor 10 embodying the present invention which can be used in assisted child delivery techniques. The vacuum extractor

10 comprises a hollow vacuum cup 12 having a base 14 and an annular side wall 20 which opens into a distal opening 18 for placement against the head of a child. In the illustrated embodiment, the vacuum cup 12 has a generally mushroom or inverted bowl shaped configuration which extends to a lower distal edge 16 which defines the distal opening 18. The side wall 20 of the cup is outwardly rounded such that the internal diameter of the cup at the lower distal edge 16 is less than the internal diameter of the cup 12 at a midpoint of the rounded side wall. The overall dimensions of the vacuum cup 12 are such that the vacuum cup 12 may be easily inserted into the birth canal and properly positioned onto the child's head. Of course, those skilled in the art will appreciate that the present invention is equally applicable to cups having other configurations including a generally bell shaped cup having an outwardly flaring edge or apron along the distal opening such as shown and described in, for example, U.S. Patent No. 5,163,944. To facilitate delivery, the embodiment of the obstetrical vacuum extractor

10 illustrated in FIG. 1, a handle 22 is provided, which, in this instance, is coupled to the cup 12 by an elongated stem 24. In order to establish a vacuum within the vacuum cup 12 and at the distal opening 18, the elongated stem 24 is hollow, or includes an interior bore 26, which opens into the interior of the hollow vacuum cup 12 via a vacuum opening 28 in the cup 12. To facilitate coupling the hollow elongated stem 24 to a vacuum source (not shown), the outer surface of its proximal end 30 is provided with a series of ribs 32 which extend about the circumferential surface of the stem 24. It will thus be appreciated that when a suitable vacuum hose, such as flexible plastic tubing (not shown), is disposed about the proximal end 32 of the stem 20, the ribs 32 ensure an airtight connection with the vacuum hose.

Preferably, the hollow vacuum cup 12, elongated stem 24 and handle 22 are unitarily molded from a substantially translucent, flexible plastic, such as polyethylene. Those skilled in the art will appreciate that the cup must be sufficiently flexible to be inserted into the birth canal and properly placed on the child's head, yet sufficiently rigid to withstand the vacuum developed within the bore 26 and cup 12. Typically, the vacuum pressure developed within the cup 12 during use ranges from about 15 to 23 inches Hg (approximately 39-59 cm Hg). Accordingly, the cup 12 must be molded of a sufficiently rigid material and the walls of the cup must be sufficiently thick to withstand the vacuum pressure. Further, the extractor 10 must be sufficiently rigid to permit the physician to positively manipulate the extractor 10 during extraction. In one preferred embodiment, a low density polyethylene such as Dow Chemical #722 has been determined to be an appropriate material. As shown in FIG. 3, additional structural strength is provided, in this case, by support ribs 34 molded into the interior of the base 14 of the cup 12.

To better distribute the applied vacuum within the cup 12, the vacuum extractor 10 may be provided with a disk (not shown) disposed a relatively short distance from the vacuum opening 28 into the interior of the hollow vacuum cup 12 as described in U.S. Patent Nos. 5,163,944 and 5,281,299. The disk is coupled to the base 14 of the cup 12 by a pair of pegs 36 (FIGS. 1 and 3) which are received within openings of the disk and then flattened by sonic welding, or the like to secure the disk to the cup 12. The disk includes a central opening through which the vacuum communicates with the interior of the cup 12. Additionally, the periphery of the disk is slightly smaller than the interior of the vacuum cup 12 such that the vacuum flow may also be distributed along the interior of the side wall 20 of the cup, the support ribs 34 assisting in distributing the vacuum force.

In accordance with the present invention, the cup is configured so that the forces which result from operation of the extractor 10 are distributed over a greater area of the fetal scalp as compared to prior art extractor designs, thereby reducing the potential for injury to the child. In particular, the cup 12 has a plurality of concentric annular beads or ridges 38 arranged on the interior of the side wall 20 of the cup so as to contact and form a seal with the head of the child when the cup is placed against the child's head. As compared to conventional extractor designs in which typically only the distal edge of the cup contacts the head of the child, the plurality of force distribution ridges 38 significantly increase the surface area of the cup which contacts and forms the seal with the child's head. Since the forces which result from the application of the vacuum and manipulation of the extractor are transmitted to the child through these contact surfaces between the cup and the child's head, providing the plurality of force distribution ridges 38 on the cup 12 allows the forces to be distributed over a greater area of the child's head. Accordingly, the potential for injury to the child caused by a concentration of forces is reduced.

In the embodiment illustrated in FIGS. 1-3, the cup 12 includes two concentric annular force distribution ridges 38a, b. Specifically, as shown in

FIGS 1 and 2, a first ridge 38a is arranged, in this instance, on the inside surface of the side wall 20 of the cup at or adjacent the distal edge 16 thereof. Preferably, this first ridge 38a is in the form of a bead 42 which is friendly to the child's scalp, minimizing the opportunity for the edge to cut or otherwise damage tissue.

The second ridge 38b is axially spaced a short distance from the first ridge 38b on the inside surface of the side wall 20 toward the base 14 of the cup. Both the first and second ridges 38a, b have, in this case, a smooth, continuous rounded configuration which eliminates any sharp edges or pinch points which may abrade the child or mother. When the cup is brought into engagement with a child's head and a vacuum applied, both the first and second ridges 38a, b contact the child's scalp and form a seal therewith. Thus, in addition to providing an increased contact area, the ridges 38 also provide a secondary sealing surface which ensures that the cup 12 forms a good, tight seal with the child's head. To further soften the contact between the extractor and the child, the extractor 10 shown in FIGS. 1-3 is fabricated of two different molded materials. The illustrated embodiment includes a relatively rigid cup portion 20a to which a lip 40 is molded of a second relatively softer material, preferably an elastomeric material. In the illustrated embodiment, the lip 40 is secured to the side wall 20 of the cup and defines the distal edge 16 thereof. The lip 40 extends along at least a portion of the inside surface of the side wall and, as shown in FIGS. 1 and 2, may extend along substantially the entire inner surface of the rigid cup portion 20a. In this case, the soft molded lip 40 also defines the first and second force distribution ridges 38a, b as well as the annular bead 42 along the outer surface of the side wall of the cup at the distal edge 16 thereof.

Those skilled in the art will appreciate that the relatively soft molded lip 40 presents a "friendly" surface for contacting the child's head, as well as maternal tissues. Further, the relatively soft lip 40 is sufficiently flexible to further enhance the seal with the child's head and to conform to any irregularities or hair present on the head. Because the lip 40 presents a relatively soft contact with the child's head, the cup portion 20a may be molded of a relatively rigid material without compromising the safety, comfort, or performance of the extractor.

It will be appreciated by those skilled in the art that the rigid cup portion 20a may be fabricated initially, and the soft lip portion 40 then molded thereto in a secondary molding operation. In order to enhance adhesion between the more rigid cup portion 20a and the softer lip 40, projections may be provided along surfaces of the rigid cup portion 20a. In the illustrated embodiment of FIGS. 1-3, an annular projection 50 is provided along the outer surface of the cup portion 20a, and two annular projections 52, 54 are provided along the inside wall of the cup portion 20a. Thus, this configuration enables the ridges to be easily formed or molded during the manufacturing process. Such a molded lip for a vacuum extractor cup is described in greater detail in U.S. Application Serial No. 08/853,422. Alternate methods may be used to enhance adhesion between the lip 40 and the cup portion 20a such as adhesives, mold through holes, or like as are described in U.S. Application Serial No. 08/853,422.

Alternatively, the force distribution ridges 138 can be arranged directly on the inside surface of the cup 112 as shown in FIG. 4. More particularly, as shown in FIG. 4, the force distribution ridges 138 are formed or molded directly into the inside surface of the side wall 120 of the cup 112. Additionally, in the embodiment of the extractor 110 shown in FIG. 4, the cup 112 includes three concentric annular force distribution ridges 138a, b, c axially spaced a short distance from one another along the inside surface of the side wall 120 of the cup. As with the embodiment shown in FIGS. 1-3, the first ridge 138a is arranged at or adjacent the distal edge 16 of the cup 112. Of course, those skilled in the art will appreciate that the cup can include any number of multiple ridges.

It will further be appreciated by those skilled in the art that the cup embodiment in FIG. 4 includes a protrusion 124 along the outer surface 121 of the cup 112 having a through-hole 122 to which a traction cord (not shown) may be coupled for manipulation by the physician. Vacuum is provided to the interior of the cup 112 via an opening 128 in the cup side wall 120.

In summary, the present invention provides a obstetrical vacuum extractor which distributes the forces which result from operation of the extractor over a greater area of the child's head than currently available vacuum extractors, thereby substantially reducing the potential for injury. The plurality of force distribution ridges have smooth rounded configurations which eliminate sharp edges and pinch points which may cause abrasion or injury to the child or mother. Moreover, the cups may be readily fabricated from conventional molding techniques.

While the invention has been described with reference to a "mushroom- shaped" cup, such as is disclosed in U.S. Patent 5,019,086, the invention is equally applicable to other extractor cup designs, such as those disclosed in U.S. Patents 5,163,944, 5,281,229, and 3,202,152, and illustrated in FIGS. 5-9. For example, U.S. Patent 5,713,909 discloses a bell-shaped cup with a sleeve which includes a flange extending radially inward over a portion of the bottom end of the cup. In accordance with the applicants' invention, radially disposed annual force distribution ridges may be provided along the outer surface of the flange which extends radially inward, as illustrated in FIG. 9. Accordingly, annular force distribution ridges may be provided along the outer surface of the cup, provided the outer surface contacts the child's head. All of the references cited herein, including patents, patent applications and publications, are hereby incorporated in their entireties by reference.

While this invention has been described with an emphasis upon preferred embodiments, it will be obvious to those of ordinary skill in the art that variations of the preferred embodiments may be used and that it is intended that the invention may be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications encompassed within the spirit and the scope of the invention as defined by the following claims.

Claims

What is claimed is:

1. An obstetrical vacuum extractor for placement on a child's head for use during childbirth, the vacuum extractor comprising, in combination: a vacuum cup having a side wall defining a hollow interior cavity, the side wall having a side wall edge forming a cup opening, the vacuum cup further including a vacuum opening in communication with the interior cavity of the cup and being adapted for connection to a vacuum source; a plurality of axially spaced annular force distribution ridges arranged along the side wall of the vacuum cup, the force distribution ridges being arranged to contact and form a seal with the child's head, and a handle coupled to the vacuum cup.

2. The vacuum extractor according to claim 1 wherein the force distribution ridges have smooth, rounded configurations.

3. The vacuum extractor according to claim 1 wherein one of the force distribution ridges is arranged adjacent the side wall edge.

4. The vacuum extractor according to claim 1 wherein the side wall includes a relatively rigid portion and a lip portion, the lip portion being constructed of a soft material secured to the rigid portion of the side wall and defining the cup opening.

5. The vacuum extractor according to claim 4 wherein at least one force distribution ridges is arranged on the lip portion.

6. The vacuum extractor of claim 4 wherein the rigid portion of the side wall includes at least one protrusion, the lip portion being coupled to the protrusion.

7. The vacuum extractor of claim 6 wherein the lip portion is molded to the rigid portion of the side wall.

8. The vacuum extractor according to claim 1 wherein the cup is substantially mushroom-shaped, the side wall of said cup having an inside surface, the force distribution ridges being formed along the inside surface of the side wall.

9. The vacuum extractor according to claim 1 wherein the vacuum cup includes two force distribution ridges.

10. The vacuum extractor according to claim 1 wherein the vacuum cup includes three force distribution ridges.

11. The vacuum extractor according to claim 1 wherein the cup is bell- shaped with an outwardly flaring edge, the force distribution ridges being formed along the outwardly flaring edge.

12. The vacuum extractor according to claim 1 wherein the cup is bell- shaped, the side wall including a flange extending radially inward to form the cup opening, the flange having an inside surface and an outside surface, at least one said distribution ridge being disposed along said outside surface.