BACKGROUND OF THE INVENTION

The invention relates generally to dilators and more specifically to disposable, non-reusable cervical dilators

ε In the gynecological field, it is sometimes necessary for a physi¬ cian to increase the diameter of the cervix through a dilation process in order to access the uterine cavity. Cervical dilation is required for procedures such as D&C, endometrial biopsy, endometrial ablation, surgical removal of myomas, fibroids, a variety of other tumors, hys- ιo teroscopy, etc. Most cervical dilators that are currently in use are reusable. Generally, these devices are hollow or solid metal cylindri¬ cal rods. Usually, a set of rods are used having diameters that are graduated in series. Additionally, each rod has a tapered end. The rods are sequentially inserted in increasing size into the cervix to ιε gradually dilate the cervical canal.

Many metal dilators have several disadvantages. For example, metal dilators are generally undesirably heavy unless they are hollow. However, if the dilator is hollow, it is more subject to incur undesir¬ able dents or disruptions in the surface of the dilator as the dilators 20 are repeatedly resterilized. Also, metal dilators may become scratched as they are cleaned or otherwise processed. These scratches and dents can produce trauma to the delicate friable cervi¬ cal tissue during the dilation procedure.

Other reusable dilators have been manufactured in the past that 25 are made of a polymer material such as Teflon. Since these dilators are reusable dilators, the materials chosen to form the dilator are al¬ ways materials that can be resterilized using conventional steam, ETO or flash sterilization techniques. Accordingly, these dilators tend to be too expensive to consider to be disposable dilators even though 30 they are made of a polymer material.

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Whenever dilators are resterilized using any of the conventional sterilization techniques, the possibility of scratching the dilators exists. It is possible for microorganisms to be harbored within these scratches and potentially survive a sterilization cycle thus exposing ε the patient to potential cross-contamination. Therefore, a need exists to provide a low-cost disposable dilator which cannot be accidently resterilized using conventional techniques and reused.

OBJECTS OF THE INVENTION

It is an object of the invention to provide a disposable cervical 10 dilator.

It is another object of the invention to provide a dilator which is deformable when subjected to steam sterilization.

It is an object of the invention to provide a series of dilators having tapered ends that are connected to a midsection which has a ιε constant diameter such that each dilator in the series _^ has a tip which is smaller than the constant diameter of the prior dilator in the series.

It is a further object of the invention to provide a cervical dilator which is simple and low-cost to manufacture.

These and other objects of the invention will become apparent 0 based on the description of the invention as set forth below.

BRIEF DESCRIPTION OF THE INVENTION

A series of disposable cervical dilators is described in which each rod in the series has at least one tapered end. Each rod is formed of a plastic material that is deformable when subjected to steam or flash 5 sterilization. In the preferred embodiment, each rod has first and sec¬ ond tapered ends. The first tapered end is connected to a midsection having a first constant diameter and the second tapered end is con¬ nected to a midsection having a second constant diameter. In the preferred embodiment, the second constant dβmeter is greater than 0 the first constant diameter. The diameter of the tip of the second ta-

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pered end is less than the constant diameter of the first midsection to provide for gradual dilation of a patient's cervical canal.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of a single cervical dilator in the pre- ferred embodiment of the invention;

Fig. 2 is a side view of a single dilator;

Fig. 3 is a perspective view of a set of cervical dilators illustrat¬ ing the graduations in size between each cervical dilator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Refer now to Figs. 1 and 2. Each dilator 10 has a first tapered end 12 and a second tapered end 14, both of which are cylindrical in cross section. The first tapered end is connected to a first midsection 16 and the second tapered end is connected to a second midsection 18. Each of the midsections are also cylindrical and have a constant diameter.

Generally, the dilators are sold as a set and the diameter of each midsection of each dilator is graduated in size with respect to the midsection of each prior and subsequent dilator in the set. In the pre- ferred embodiment of the invention, the increase in diameter between each dilator midsection in the set is one millimeter. The diameter of the tip 20 of the second end is always slightly smaller than the diame¬ ter of the first midsection 16. In the preferred embodiment of the in¬ vention, the diameter of the tip 20 is at least 50% smaller than the diameter of the preceding midsection 16 in the set of dilators.

In one embodiment of the invention, the first and second mid¬ sections 16, 18 are connected to form a ridge 22 at the juncture of the first and second midsections. This ridge always slants inwardly from the larger midsection 18 toward the smaller midsection 16. The purpose of this ridge will be discussed in greater detail below.

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As can be seen in Fig. 1, in the preferred embodiment of the in¬ vention, each end of the cervical dilator 10. includes a slight curve between the juncture of the tapered end 12, 14 and its corresponding midsection 16, 18. The purpose of the curve is to more easily ac- 5 commodate for any curves in the course of the cervical canal.

Refer now to Fig. 3 which illustrates a set of cervical dilators. As can be seen in the figure, each dilator is slightly larger than its proceeding dilator in the set. In use, a physician typically begins a dilation procedure by inserting the smallest tip of the smallest dilator io in the set into a patient's cervical canal and advances the dilator until the corresponding midsection has been introduced into the cervical canal. The dilator is then withdrawn and rotated to introduce the op¬ posite end of the dilator into the canal to gradually dilate the canal. This dilator is then removed and the next larger dilator in the set is in- i5 troduced; the process is repeated until the desired dilation is obtained.

It is important that the physician have an easy way of identifying which dilator end should be inserted into a patient's cervix at any given time during the dilation procedure. The ridge discussed above provides a simple means of allowing a doctor to determine whether o the opposite end of the same dilator is to be subsequently inserted into the cervical canal or whether a separate dilator in the set should be obtained for insertion. Since the ridge always slopes downwardly from the larger end of the dilator to the smaller end, a physician can feel which end of the dilator is the smaller end simply by running his 5 or her finger over the ridge of the dilator prior to insertion to deter¬ mine which end of the dilator should normally be inserted first.

Another method to assist a physician in determining which dila¬ tor tip should be inserted into the cervical canal is to provide an indi¬ cation of the diameter in millimeters of each midsection. This is ilius- 0 trated in the preferred embodiment of Fig. 3.

In the preferred embodiment of the invention, each dilator is formed of a plastic material which is deformable when subjected to

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steam or flash sterilization. This prevents accidental resterilization and subsequent reuse of a dilator.

in the preferred embodiment, the plastic chosen is a polyolefin material. A particularly preferred polyolefin is a random copolymer polypropylene. It is preferred that the material have a deflection tem¬ perature (or deformation temperature) of not greater than 250° F. In other embodiments, the deflection temperature of the material chosen may range from 150° F to 250° F. In the preferred embodiment, the deflection temperature is 189° F.

While the invention has been described in detail and with refer¬ ence to specific embodiments thereof, it will be apparent for those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention.

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