AU5331794A - Endocervical probe for pap smear sampling head - Google Patents

Description

Title: "ENDOCERVICAL PROBE FOR PAP SMEAR SAMPLING HEAD"

FIELD OF THE INVENTION

The present invention relates to pap smear sampling devices of the type used in the gynaecological field for the detection of cancer cells in the female cervix. BACKGROUND OF THE INVENTION

A number of sampling devices have hitherto been available to conduct these so-called "pap smear" tests. Such devices are generally adapted to be inserted into the cervix and then rotated so as to wipe or scrape the surface of the cervix, in an attempt to collect and retain a representative sample of cells. Once the sample has been taken, at least a proportion of the cells collected on the sampler are transferred to a glass optical slide for subsequent examination under a suitable microscope, in an attempt to ascertain the cancer status of the cervix. This procedure is well known and understood by those skilled in the art, and so will not be described in more detail here.

It has been found in practice, however, that known pap smear sampling devices are inadequate in a number of significant respects. It has been shown statistically that the accuracy of cervical cancer detection is relatively low, and many cases go undetected in the early stages largely as a result of the inefficiency of the various pap smear sampling devices currently in use.

One known type of sampling device is typically formed from wood and incorporates a sampling head corresponding generally to the cross sectional surface profile of the cervix. However, such "spatula" type devices are excessively rigid, and so are not well adapted to properly accommodate the wide variations in size and shape of cervix which are routinely encountered. Moreover, because of the inability of these rigid spatulas to conform flexibly to the relatively complex and varied surface contours of the cervix, the effective area of coverage during the sampling procedure is relatively small. This in turn can lead to inaccurate diagnosis, and can also cause excessive pain and discomfort to the patient. The spatula type samplers also have a tendency to cause contact bleeding which makes detection of cancer cells amongst the interspersed red blood cells considerably more difficult and less accurate. In an attempt to ameliorate these problems, a number of prior art devices have incorporated various configurations of bristles, fibres, filaments or brushes, which are generally mounted on support arms or wires. However, these "brush" type devices can also cause substantial pain and bleeding particularly if sufficient care is not exercised during the sampling procedure. Such samplers do tend to give better surface coverage than the rigid spatula type devices discussed above, by virtue of the fact that the bristles can resiliently deform a certain extent, thereby enabling the brush to conform more closely to the surface contours of the cervix. However, these devices still cannot provide complete coverage and in addition suffer the inherent problem or poor transferability of the collected sample to the microscope slide for subsequent analysis. This is largely because the sample cells tend to remain trapped in the interstitial voids between the bristles within the inner confines of the brush, and are therefore not readily accessible and transferable to the slides. Again, this leads to inaccurate diagnosis, particularly in the critical preliminary stages of cervical cancer.

Moreover, with both the major types of known samplers discussed above, the cancer cells and dysplastic cells are often damaged or deformed during the sampling procedure, and so become more difficult to detect accurately with known diagnostic techniques. This reduces even further the accuracy of the pap smear test as currently practiced, in terms of its ability to provide an early and reliable indication of cervical cancer.

In addition to the above considerations, a particular problem relates to the portion of known sampling devices adapted specifically to collect sample cells from the inner walls of the cervical canal or endocervix. Most prior art devices incorporate either a relatively rigid or brush type endocervical probe or stem extending axially from the handle of the instrument to permit insertion into the cervix. However, the brush type endocervical sampling stems suffer the same inadequacy in terms of poor sample transfer as discussed above. The more rigid type devices suffer the problem of poor surface coverage as discussed above, and in addition, any sample cells that are collected tend to be wiped from the stem upon withdrawal from the cervical canal. It has now been realised that in both cases, sampling is particularly inefficient because of the inability of the sampler to expand into scraping contact with the endocervical canal. These and other disadvantages make the various prior art samplers particularly ineffectual in recovering a representative sample of cells from the endocervix.

It is therefore an object of the present invention to provide an improved pap smear sampling device which overcomes or substantially ameliorates at least some of the above mentioned disadvantages of the prior art. DISCLOSURE OF THE INVENTION

Accordingly, the invention as presently contemplated provides a pap smear sampling device for use in the detection of cancer cells in the female cervix, said device comprising a sampling head adapted to engage and scrape the surface of the cervix for collection of sample cells, and an elongate handle to permit remote rotation and manipulation of the sampling head, said sampling head comprising at least two outwardly bowed resilient arms extending generally axially from the handle, said arms being disposed to move together into a closed configuration upon insertion into the cervix and thereafter to resiliently expand within the endocervical canal into an open configuration in scraping contact with the endocervix, said arms being adapted flexibly and resiliently to conform to the surface contours of the endocervical canal in the open configuration and to collect sample cells therefrom upon rotation and manipulation of the sampling head.

Preferably, the arms are joined at their terminal ends to form a tip remote from the handle, the arms thereby defining an intermediate elongate aperture to retain sample cells.

The device preferably also incorporates a flexible blade portion extending generally outwardly from the base of the sampling head simultaneously to scrape and collect sample cells from the ectocervix. The blade is preferably adapted flexibly to conform to the surface contours of the ectocervix, whilst maintaining an effective scraping angle upon rotation and manipulation of the sampling head.

In one preferred embodiment, the blade is defined by the marginal edge of a relatively flexible web and the sampling head further includes a relatively rigid support arm extending outwardly from the handle or the stem to support the remote end of the web.

Preferably also, the device includes a relatively flexible joint disposed to permit a degree of relative axial misalignment between the handle and the sampling head. This enables effective rotation and manipulation of the device with the handle inclined at an oblique angle with respect to the head.

In the preferred embodiment, the flexible joint is conveniently provided by an intermediate neck region of reduced cross sectional area at the base of the sampling head.

The sampling head is preferably formed substantially from a suitable elastomeric material such as rubber, santoprene, silicon, flexible polyurethane, polyethylene, polypropylene, polypropylene, epoxy, polyester and acrylic. The end of the handle remote from the sampling head preferably terminates in a flattened blade adapted to scrape the ectocervix, in cases where an endocervical sample is not required.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:-

Figure 1 is a front elevation showing a pap smear sampling device according to a first embodiment of the invention; and

Figure 2 is an elevation view similar to Figure 1 showing an alternative embodiment.

PREFERRED EMBODIMENT OF THE INVENTION Referring firstly to Figure 1, the invention provides a pap smear sampling device 1 for use in the detection of cancer cells in the female cervix (not shown) in accordance with the established gynaecological "pap smear" testing procedure, which is well known and understood by those skilled in the art. The sampling device includes a sampling head 5 adapted to engage and scrape the surface of the cervix for collection of sample cells, and an elongate handle 6 to permit remote rotation and manipulation of the sampling head when engaged with the cervix.

The sampling head 5 comprises a pair of mutually opposed outwardly bowed resilient arms 10 extending generally axially and from the handle. The bowed arms 10 together define a stem 11 and are joined at their remote ends to form a tip 12 of the sampling head. In this way, the arms also define an intermediate aperture 13 similar in configuration to an enlarged eye of a needle.

A flexible wiping blade 15 extends outwardly from the base of the sampling head. In the embodiment of Figure 2, a support arm 17 extends from the base of the sampling head to the remote end of the wiping blade to provide support for the blade.

In each case, the operative edge of the wiping blade is adapted to progressively curve along its length through an angle of between around 90° to 180°, and preferably around 140° from the stem defined by the arms 10. That is to say, a tangent projected from the remote tip of the operative edge of the wiping blade intersects a projected axis of the stem and handle at an included angle of between 0° and 90°, and preferably around 40°. This extent of curvature ensures adequate coverage of the ectocervix, and transition zone.

The handle 6 includes a neck region of reduced cross sectional area immediately adjacent the base of the sampling head to form a relatively flexible "universal" joint 25. This joint permits a limited degree of relative movement and axial misalignment between the handle and the sampling head which enables effective manipulation of the head with the handle inclined at an angle with respect thereto. Other forms of flexible joint are also envisaged. In both embodiments, the end of the handle remote from the sampling head terminates in an additional sampling blade 30 for use in applications not requiring penetration of the cervix.

Turning now to describe briefly the method of use, the sampling device is first positioned in the conventional manner and the probing stem 11 inserted into the cervix. During this insertion procedure, the resilient arms 10 straighten and move together, thereby substantially closing the intermediate aperture 13. This contraction reduces the effective cross sectional area of the stem, and thereby facilitates insertion with minimum patient discomfort and injury. As the stem advances further into the endocervical canal, the arms 10 resiliently expand outwardly so as to positively engage the inner walls of the endocervix. With the sampler finally in position, the wiping blade 15 simultaneously engages the the ectocervix. The device is then manually rotated by the handle, in either the clockwise or anti-clockwise direction.

During this rotation and manipulation, the outer edges of the resilient arms 10 scrape the endocervix whereby sample cells are collected and retained on the various faces of the arms, as well as in the intermediate aperture or eye 13. It will be appreciated that during this process, the resilient nature of the bowed scraping arms 10 enables the stem flexibly and resiliently to conform to any irregularities in the surface profile of the cervical canal whilst maintaining a reasonably constant outwardly directed contact pressure. This maximises the contact area, minimises localised pressure concentrations and ensures that a representative sample is obtained.

Simultaneously, the wiping blade 15 scrapes the ectocervix, whereby sample cells are collected and retained on the frontal surface of the blade. During this operation, as a result of axial pressure applied by the operator, the wiping blade flexibly and progressively conforms to the complex profiles of the cervix, including any surface irregularities. In the case of the embodiment of Figure 2, the support arm 17 helps to ensure that an effective scraping angle is maintained over the entire cervix by providing support for the end of the wiping blade remote from the stem and permits a substantially uniform pressure distribution across the blade. This embodiment is particularly suitable for nullipara patients, whereas the embodiment of Figure 1 is especially suited to multipara patients.

Once the sampling procedure has been completed, the device is withdrawn. Again, during withdrawal, the arms 10 are permitted to resiliently straighten and contract so as to minimise discomfort and injury to the patient.

The sample cells from the arms 10, the intermediate aperture 13 , and the web or blade 15 are then transferred by a simple wiping action onto an appropriate optical slide for subsequent analysis and testing in accordance with established diagnostic procedures. A simple wiping action is sufficient to transfer the entire sample from the frontal face of the blade 15 onto the slide. Consequently, substantially the entire collected sample is available for analysis.

It will be apparent that the present invention provides a number of significant advantages over the prior art. Firstly, as a result of its inherent "form fitting" capability, the effective area of coverage of the cervix, and in particular the endocervix, during the sampling procedure is greatly increased, especially when compared with the rigid prior art spatula type devices.

Furthermore, the device according to the present invention enables virtually complete transfer of the collected sample to a microscope slide for subsequent analysis. There is minimal possibility for sample cells remaining trapped in interstitial voids such as occur between the bristles, fibres or filaments of the prior art brush type devices. Moreover, the cells retained in the aperture or eye 13 tend not to be inadvertently wiped off upon withdrawal of the stem from the endocervical canal. As previously mentioned, on a statistical analysis these factors significantly reduce the probability of inaccurate diagnosis.

Additionally, the flexible joint provided intermediate the sampling head and the handle enables the device to accommodate a significant degree of operator error, by virtue of the fact that the sampling head is adapted automatically to assume the optimum position around the cervix, despite relative axial misalignment of the handle within a reasonably broad range of tolerance.

The improved configuration and flexibility of the sampling head thus enables the device to accommodate a wide variation in cervix size and shape, whilst affording precise control and minimising pain, discomfort, bleeding, and cell damage. More particularly, the ability of the bowed arms of the stem to contract upon insertion into the cervix minimises patient discomfort as well as damage to the cervix and the sample cells, whilst the subsequent radial expansion into the open configuration within the endocervical canal maximises coverage, again with minimal discomfort and damage. By reducing contact bleeding and cell damage in this way, the likelihood of inaccurate diagnosis of the cancer status of the cervix is further reduced. Sampling time is also significantly reduced because the device is able to provide an effective and accurate first-time sample. The accuracy and specificity of the diagnosis is further enhanced by enabling distinct inside and outside cervical samples to be taken simultaneously, and subsequently isolated on separate slides for individual analysis if required. For these reasons, it will be apparent that the present invention represents a commercially significant improvement over the prior art.

Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. For example, the operative edge of the wiping blade may be scalloped if required.

Claims (16)

1. A pap smear sampling device for use in the detection of cancer cells in the female cervix, said device comprising a sampling head adapted to engage and scrape the surface of the cervix for collection of sample cells, and an elongate handle to permit remote rotation and manipulation of the sampling head, said sampling head comprising at least two outwardly bowed resilient arms extending generally axially from the handle, said arms being disposed to move together into a closed configuration upon insertion into the cervix and thereafter to resiliently expand within the endocervical canal into an open configuration in scraping contact with the endocervix, said arms being adapted flexibly and resiliently to conform to the surface contours of the endocervical canal in the open configuration and to collect sample cells therefrom upon rotation and manipulation of the sampling head.

2. A device according to claim 1, wherein said arms are joined at their respective terminal ends to form a tip remote from the handle, the arms thereby defining an elongate aperture therebetween.

3. A device according to claim 2, wherein said aperture corresponds in configuration generally to that of a needle eye.

4. A device according to claim 3, wherein said arms together in the closed configuration form a substantially straight stem coaxial with said handle.

5. A device according to claim 4, wherein the outer periphery of said arms in the open configuration is generally oval shaped.

6. A device according to claim 5, further including a flexible blade portion extending generally outwardly from a base region of the sampling head thereby simultaneously to scrape and collect sample cells from the ectocervix.

7. A device according to claim 6, wherein said blade portion is adapted flexibly to conform to the surface contours of the ectocervix, whilst maintaining an effective scraping angle upon rotation and manipulation of the sampling head by the handle.

8. A device according to claim 6 or claim 7, wherein said blade portion is defined by a marginal edge of a relatively flexible web and wherein the sampling head further includes a relatively rigid support arm extending outwardly from the handle or the stem to support the remote end of said web.

9. A device according to claim 8, wherein said web and said support arm are integrally moulded.

10. A device according to any one of the preceding claims, further including a relatively flexible joint disposed to permit a degree of relative axial misalignment between the handle and the sampling head, thereby permitting effective rotation and manipulation of the device with the handle inclined at an oblique angle with respect to the head.

11. A device according to claim 10, wherein said joint is defined by an intermediate neck region of reduced cross-sectional area intermediate the sampling head and the handle.

12. A device according to any one of the preceding claims, being formed from a substantially elastomeric material.

13. A device according to claim 12, being formed from a substantially elastomeric material selected from the group comprising rubber, santoprene, neoprene silicon, polyurethane, polyethylene, polypropylene, epoxy, polyester and acrylic.

14. A device according to any one of the preceding claims, wherein the handle remote from the sampling head terminates in a flattened blade portion adapted to scrape the ectocervix in cases where an endocervical sample is not required.

15. A device according to any one of claims 6 to 14, wherein the wiping blade is progressively curved along its length through an angle of between 90° and 180° such that a tangent projected from the remote tip of the wiping blade intersects a projected axis of the stem and handle at an included angle of between 0° and around 90°.

16. A device according to claim 15 wherein the operative edge of the wiping blade is progressively curved along its length through an angle of around 140° 17. A device substantially as hereinbefore described with reference to the accompanying drawings.