Apparatus for assisting childbirth

The invention consists of novel, scissors-like forceps in combination with optical monitoring hardware for measuring the extraction forces on a fetal head. The novel features of the forceps together with knowledge of real time forces on the fetal head enable a user to make a much safer delivery for mother and baby.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention pertains to devices for assisting in childbirth. 
Specifically, the present invention pertains to an improved version of 
obstetrical forceps. 
2. Background Information 
Many devices have been developed over the years to assist in the delivery 
of babies. These devices have included forceps, cylindrical net-like 
devices, suction devices, and miscellaneous other devices. The forceps 
typically grasp the fetal head in a scissors-like manner. Examples of such 
forceps include U.S. Pat. Nos. 3,665,925, 3,785,381, 3,789,849. The 
cylindrical net-like devices typically grasp the fetal head automatically 
when tension is applied to the net. Examples of net-like devices include 
U.S. Pat. Nos. 4,597,391, 4,875,482, 5,122,148, and 5,217,467. The suction 
devices simply grasp the fetal head with suction. An example of a suction 
device can be found in U.S. Pat. No. 3,794,044. Other devices include U.S. 
Pat. No. 3,848,606 (which consists of a concave surface that is attached 
to the fetal head with an adhesive) and U.S. Pat. No. 5,139,503 (which 
consists of a pair of spatulas that are attached to and pivot from the 
ends of a semicircular segment). The goal of all these devices has been to 
minimize, if not completely eliminate, the risk of injury to both the 
mother and the fetus. However, as a practical matter, such devices have 
been ineffective or just too difficult to use. 
SUMMARY OF THE INVENTION 
This invention has the ability to assist in the safe delivery of a fetus. 
The invention consists of novel, scissors-like forceps in combination with 
optical monitoring hardware for measuring the extraction forces on a fetal 
head. The novel features of the forceps together with knowledge of real 
time forces on the fetal head enable a user to make a much safer delivery 
for mother and baby. 
An object of this invention is to enable the user to safely grasp and pull 
on the head of a fetus while assisting in the birthing process. 
Another object of this invention is to provide the user with real time 
knowledge of both the compressive and tractive forces exerted on the head 
of the fetus. 
Still another object of this invention is to automatically limit the 
maximum compressive force that can be added to the fetal head during 
delivery. 
A further object of this invention is to provide an instrument that can be 
either easily sterilized for reuse or disposed of at a reasonable cost.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A preferred embodiment of this invention comprises scissors-like forceps 
having flexible spatula ends, a first and a second optical means for 
sensing strain embedded within the forceps, a means for transmitting an 
optical signal, a means for receiving a reflected optical signal, an 
optical fiber connecting the two strain sensing means to the transmitting 
means and the receiving means, and a means for analyzing and displaying 
the reflected optical signals. 
FIG. 1 shows scissors-like forceps consisting of a first member 10 having a 
flexible spatula end 11 and a rigid handle end 12. Similarly, FIG. 1 shows 
a second member 20, much like the first member 10, having a flexible 
spatula end 21 and a rigid handle end 22. A means for pivoting 30 is 
provided between the flexible spatula ends 11, 21 and the rigid handle 
ends 12, 22 (located approximately at midpoints of the first and second 
members) for pivoting the first member 10 relative to the second member 20 
in a scissors-like manner. A first and a second optical means for sensing 
strain 41, 42 (shown in FIG. 4, but not FIG. 1) are embedded within the 
first member 10 and are connected with optical fiber 50 to a means for 
transmitting an optical signal 60, which is shown together in FIG. 1 with 
a means for receiving a reflected optical signal. A means for analyzing 
and displaying reflected optical signals 70 is shown integrally with the 
transmitting/receiving means 60 in FIG. 1. 
FIG. 2 shows the rigid handle ends 12, 22 in the same position as FIG. 1. 
However, in FIG. 2, broken lines are used to demonstrate the flexibility 
of the spatula ends 11, 21 when the forceps are used to grasp the fetal 
head. A primary advantage of the flexible spatula ends 11, 21 is to 
prevent injury to the fetal head. Another safety feature is a projection 
23 on rigid handle end 22. The projection 23 on rigid handle end 22 
prevents the flexible spatula ends 11, 21 from being squeezed further 
together once the projection 23 comes into contact with the other rigid 
handle end 12. Thus, the projection 23 automatically limits the maximum 
compressive force that can be added to the fetal head from the forceps 
during delivery. Obviously, there are many ways the projection 23 can be 
fabricated into either the first and/or second member in order to function 
as an automatic stop. 
FIGS. 3 and 4 represent orthogonal views of the first member 10. In FIG. 3, 
the flexible spatula end 11 of the first member 10 is clearly shown. In 
FIG. 4, the rigid handle end 12 and part of the flexible spatula end 11 
are shown in section to demonstrate the placement of the first and second 
optical means for sensing strain 41, 42. Since a combination of both 
flexural or bending (from squeezing the fetal head) and tensional (from 
pulling on the fetal head) forces will be exerted on the first member 10 
during the use of this invention, a minimum of two strain sensing means 
will be required in order to mathematically separate the flexural force 
from the tensional force. Preferably, the two strain sensing means should 
be located near extreme bending fibers with one strain sensing means in 
the compressive bending zone and the other strain sensing means in the 
tensional bending zone. The preferred bending zone is in the flexible 
spatula end 11 of the first member 10 adjacent to the means for pivoting 
30. The preferred configuration for the strain sensing means is shown in 
FIG. 4 by the first optical strain sensing means 41 and the second optical 
strain sensing means 42. 
While a number of optical strain sensing means are commercially available, 
the preferred strain sensing means consists of an optical grating. The 
optical grating reflects a portion of a transmitted optical signal having 
a specific wavelength. The wavelength of the reflected signal is 
proportional to the spacing of the grating. When the spacing of the 
grating is changed, the wavelength of the reflected optical signal 
changes. Consequently, by embedding the optical grating within the first 
member 10, a force-induced strain in the grating will result in a specific 
change in the wavelength of the reflected signal. In other words, a change 
in the grating spacing will cause a different portion of the optical 
signal to be reflected. In addition, by monitoring the change in the 
wavelength of the reflected signal, the loads induced by the fetal head on 
the flexible spatula ends 11, 21 of the first and second members 10, 20 
(and, inversely, the loads placed on the fetal head by the flexible 
spatula ends 11, 21 of the first and second members 10, 20) can be 
determined. 
The transmitting/receiving means 60 can be any commercially available 
system that is capable of transmitting an optical signal and receiving a 
reflected optical signal. The means for analyzing and displaying reflected 
optical signals 70 can also be readily accomplished by one having ordinary 
skill in structural analysis techniques using commercially available 
equipment. Mathematically separating flexural loads from tensional loads 
is a very basic structural calculation. 
The preferred material for the first and second members 10, 20 is any 
commercially available thermoplastic material that has been approved for 
medical applications and that is stable enough to allow sterilization by 
heat or radiation. The optical grating for the optical means for sensing 
strain 41, 42 can be fabricated directly into commercially available 
optical fiber with known methods. 
An alternative embodiment of the apparatus for assisting childbirth would 
be identical to the preferred embodiment described above with one 
addition. The addition would consists of a pair of strain sensing means 
for the second member. The addition of a second pair of strain sensing 
means 49 and 50 to the second member could perform two functions. First, 
the second pair 49 and 50 could serve as a check or backup for the first 
pair. Second, the second pair could be used in conjunction with the first 
pair to monitor more dynamic loading conditions. For example, in the event 
the forceps needed to be used in a side.-to-side manner rather than in a 
typical squeeze-and-pull manner, the readings from just one of the members 
may not give the user a total picture of the forces being exerted on the 
fetal head. However, if both members were monitored, all possible loads 
could be identified. A second pair of strain sensing means for the second 
member can be visualized by referring to FIG. 4. 
Before the apparatus for assisting childbirth can be used, the apparatus 
will first have to be calibrated to account for any differences in 
operation between the two optical sensors and any differences in placement 
of the two sensors with respect to the extreme fibers in bending. The best 
way to calibrate the apparatus is to compare the reflected signal from 
both sensors under a zero-load condition to the reflected signal from both 
sensors while the first and second members are being subjected to a pure, 
predetermined flexural load. A pure flexural load can be obtained by 
squeezing an object with the spatula ends of the first and second members. 
By knowing how the sensors respond to a pure flexural load, any 
combination load can be mathematically separated into its flexural and 
tensional components. 
Once the apparatus has been calibrated, it can be used like any ordinary 
set of obstetrical forceps. However, with this apparatus, the user will 
know exactly how much pressure and traction is being exerted on the fetal 
head.