Vaginal sampling device

Abstract

Vaginal sampling device comprising an insertion member 12 having a distal, insertion end, and a closable interior cavity 28; attached to the member is an inflatable flexible membrane 50 having an oute

Description

FIELD OF THE INVENTION The present invention relates to apparatus for vaginal sampling, such as for obtaining biospecimens for cytopathological examination. BACKGROUND ART Cervical screening is widely used to detect potentially precancerous and cancerous processes in the cervix. Abnormal findings are often followed up by more sensitive diagnostic procedures and, if warranted, interventions that aim to prevent progression to cervical cancer. The universally-used test was invented in the 1920s by the Greek physician Georgios Papanikolaou and named after him. It is often abbreviated as Pap test or Pap smear, and is also referred to as a cervical smear, cervical screening, or smear test. A Pap smear is performed by opening the vagina with a speculum and collecting cells at the outer opening of the cervix at the transformation zone (where the outer squamous cervical cells meet the inner glandular endocervical cells), using an Ayre spatula or a cytobrush. The collected cells are examined under a microscope to look for abnormalities. The test aims to detect potentially precancerous changes caused by human papillomavirus. The test remains an effective, widely used method for early detection of precancer and cervical cancer. Guidelines on when to begin Pap smear screening are varied, but usually begin in adulthood. Guidelines on frequency vary from every three to five years; in the United Kingdom women between the age of 25-49 are invited for a smear test every three years, and women past 50 every five years. If results are abnormal then (depending on the nature of the abnormality) the test may need to be repeated in six to twelve months. If the abnormality requires closer scrutiny, the patient may be referred for detailed inspection of the cervix by colposcopy and / or referred for HPV DNA testing. Whilst the pap smear is highly regarded and beneficial in identifying cases of cervical cancer at an early stage, it is often uncomfortable for the patient thanks to the speculum and spatula required to be used. In addition to being intrinsically undesirable, this tends to dissuade patients from attending clinics and limits the effectiveness of screening programs. US3664328 discloses a cervical specimen gathering device employing a balloon which can be inflated within the vaginal canal and which is coated with a fibrous flocculent material described as being absorbent and somewhat abrasive. The inflated balloon is rotated to collect a sample of material from the vaginal wall. The device has little control of the amount of sample which is collected and appears no more comfortable than a pap smear. Other tissue sampling techniques are employed to secure tissue samples from other bodily locations, including US6171259 and WO2006 / 003447A1 for colorectal sampling. US6171259 relates primarily to temperature sensing and collection of fecal specimens and is therefore not relevant, whilst WO2006 / 003447A1 discloses a device unsuited to vaginal use. "Proteomic Biomarkers for the Detection of Endometrial Cancer", Cancers (Base!) 2019 Oct; 11(10): 1572 discusses different sampling methods with advantages and disadvantages and emphasises the importance of screening and early diagnosis. SUMMARY OF THE INVENTION The present invention seeks to provide apparatus for vaginal biospecimen collection which can reliably collect a suitable specimen for cytopathological, molecular or other examination but which does not have the discomfort of a conventional pap smear test. This would be relevant to cervical cancer and to other diseases such as ovarian cancer, endometrial cancer, and certain other non-cancerous diseases, which are currently detected via methods other than vaginal sample collection. The present invention therefore provides a vaginal sampling device, comprising an insertion member having a distal, insertion end, a proximal end and a closable interior cavity; a flexible membrane having an outer, cell sampling surface and an inner surface, wherein said membrane is sealingly attached to the distal, insertion end of said insertion member and held within the interior cavity; such that, in use, pressurisation of the interior cavity to at least a first elevated pressure causes the membrane to emit from the distal end of said insertion member to make contact with the vaginal mucosal surface and pressurisation of the interior cavity to a second reduced pressure causes the membrane to invert and return to the interior cavity of said insertion member; the insertion member having an exterior surface comprising an elongate tip portion with a smooth exterior surface which extends from the distal, insertion end at least as far back as a stop portion comprising at least one transversely-protruding lip extending outwardly from the smooth exterior surface of the tip portion thereby to inhibit insertion beyond the stop portion.Such an arrangement allows a biospecimen sample to be obtained with greater accuracy and with far less discomfort to the patient than with conventional devices. Preferably, the insertion member comprises an inner section at least part of which is a hollow tubular section thus defining the interior cavity, and a separate outer sleeve attachable to the inner section to extend around the inner section rearwardly from the distal, insertion end, and which includes the at least one lip. The outer sleeve may also include the elongate tip portion with a smooth exterior, which ensures that the device is suitable for vaginal use. The outer sleeve can be attachable to the inner section via screw threads provided on an outer surface of the inner section and an inner surface of the outer sleeve. Conveniently, the screw threads are located proximate the distal, insertion end. The stop portion may comprise a plurality of transversely-protruding lips, which prevents unintentional trauma by the device being inserted too far, and also positions the device accurately within the vagina. The pair of transversely-protruding lips can be arranged symmetrically either side of the insertion member. The flexible membrane is preferably elastic and may be constructed from a nitrile, latex or rubber based substance There may be means for pressurisation of the interior cavity, said means being attached to the proximal end of the insertion member. The said means for pressurisation of the interior cavity can be attached to a valve, such as a self- sealing valve, present at the proximal end of the insertion member. The means for pressurisation of the interior cavity could comprise a source of compressed air or a syringe The surface area of the outer, cell sampling surface of said flexible membrane is preferably reproducibly controllable. Additionally or alternatively, the surface area is controlled by the means for pressurisation of the interior cavity. Suitably, the insertion member is adapted to engage with a sealing means, such as a threaded cap, to seal said receptacle. The means for pressurisation of the interior cavity may be detachable from the insertion member. BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the present invention will now be described by way of example, with reference to the accompanying figures in which; Figure 1 shows an isometric view of the device according to the present invention; Figure 2 shows a side view of the device according to the present invention; Figure 3 shows the device of the present invention ready for use; Figure 4 shows an exploded view of the principal parts of the device of the present invention; Figure 5 shows a sectional view of the operative tip section of the device of the present invention; Figures 6 and 7 show rear and frontal isometric views (respectively) of the introducer part of the present invention; and Figures 8 to 20 illustrate sequential steps in the operation of the device according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS An example of the present invention will now be described with reference to figures 1 to 7 which illustrate the vaginal cell sampling device. The sampling device 10 comprises an insertion member 12 which is generally elongate and cylindrical, at the rear of which a syringe 14 is connected in order to provide a supply of compressed gas such as air. The syringe 14 is, in this example, conventional in comprising a barrel 16 enclosing a plunger or piston 18 at the end of which a seal 20 seals the gap between the outside of the plunger 18 and the inner cylindrical face of the barrel 16. Thus, the plunger 18 can be pulled or pushed linearly along the inside of the barrel, allowing the syringe to take in and expel gas through a discharge orifice 22 at the front (open) end of the barrel 16. Graduations 24 on the exterior cylindrical surface of the barrel 16 allow measurement of the total volume within the barrel dependent on the position of the plunger 18. Other sources of compressed gas can be used, such as pump or bulb or compressor. The insertion member 12 comprises an inner section 26 in the form of a hollow tubular section which defines an interior cavity 28, and a separate outer sleeve 30 attachable to the inner section so as to extend around the inner section rearwardly from the distal, insertion end 32. In this example, the outer sleeve 30 attaches to the inner section via an external screw thread 34 on the outer cylindrical face of the inner section 26 in (at least) the vicinity of its distal, insertion end 32 and a corresponding screw thread on the inner cylindrical face of the outer sleeve 30. The outer sleeve 30 ensures that the device 10 is suitable for vaginal use. Its outer surface 36 is smooth and rounded, extending from the distal, insertion end 32 around a sampling orifice 38 which aligns with the distal end of the internal cavity 28, rearwardly to a stop member 40. This consists of two transversely-protruding lips 42 which extend outwardly from the smooth outer surface 36 and inhibit further insertion. Two lips are provided in this example, arranged symmetrically either side of the outer sleeve 30, but more or fewer could be provided. Other stop structures could be provided, such as a continuous collar around the outer sleeve 30 acting as a single lip. The transversely-protruding nature of such a lip or lips provides a physical barrier to further insertion; this prevents unintentional trauma, and also positions the device 10 within the vagina so as to provide adequate space for the sample collection process described below. A collar 44 acts as an adaptor to connect the proximal end 46 of the inner section 26 to the syringe 14 or other source of compressed gas. It connects to the inner section 26 via a screw thread 48 on the outer surface of the proximal end of the inner section 26, and to the syringe 14 via conventional means. A flexible membrane 50 is provided, initially located within the inner section 26 and connected around the sampling orifice 38. It is in the form of an inflatable bulb, closed apart from one orifice communicating with the sampling orifice 38. From its initial location within the inner section 26, supply of compressed gas to the inner section 26 by compressing the plunger 18 of the syringe 14 will cause the membrane 50 to inflate and extend out of the sampling orifice 38 as illustrated in figures 1 and 2. Subsequent withdrawal of the plunger 18 will cause the air or other gas previously supplied to the inner section 26 to be withdrawn, deflating the membrane 50 and withdrawing it into the inner section 26 to its original state. The membrane 50 has an outer, cell sampling surface and an inner surface, and is, as noted above, sealingly attached to the distal, insertion end of the insertion member and initially held within the interior cavity. Thus, the membrane can be kept safe and clean within the interior cavity until needed. Once inserted into a vagina, it can then be inflated or otherwise pressurised to at least a first elevated pressure, which will cause the membrane to emit from the distal end of the insertion member and make contact with the vaginal mucosal surface. Reducing that pressurisation to a second, reduced pressure will cause the membrane to invert and return to the interior cavity of said insertion member. The insertion member can then be withdrawn with the membrane and specimen safely contained within the interior cavity. Thus, the membrane and specimen will be kept safe from subsequent contamination and can be sent to a suitable facility for the biospecimen captured on the membrane to be analysed. The process of sampling using the above-described device will now be described with reference to figures 8 to 21. The sampling device is used for the collection of exfoliated cells and other material from the surface of the vagina wall for subsequent analysis. A single size of the device is suitable for essentially all adult females (i.e. over 18 years of age). An initial digital vaginal (PV) examination should be undertaken in order to confirm that the sampling procedure is appropriate, feasible and safe. The plunger 18 of the syringe 14 should then be withdrawn to (in this case) the 80 mL mark (figure 8). The inner section 26 of the insertion member 12 is ideally supplied within a sterile pouch and with a screw cap 52 fitted over the sampling orifice 38 (in place of the outer sleeve 30) to seal and retain the membrane 50 in position. The inner section 26 is removed from the pouch and the cap removed and retained (figure 9). The syringe 14 is screwed into the base / adaptor 44 of the insertion member 12 until at least finger tight (figure 10). It need not be tightened further. The device can be tested in this configuration by fully or partially depressing the syringe plunger (figure 11); the membrane should remain inflated for around 10 seconds but should not be touched at this stage in order to maintain sterility. The plunger 18 can then be withdrawn to fully retract the membrane 50 into the interior cavity 28. The device is now ready for use. The outer sleeve 30 can be screwed onto to the end of the insertion member 12 (figure 12) and lubrication applied externally to the device. The tip of the insertion member 12 can be placed into the introitus (figure 13a, 13b) with the labia separated and the lips 42 of the stop member 40 horizontal relative to the patient. The stop member 40 is (as noted above) present in order to prevent further penetration into the vagina and the device is not required to be pushed all the way to the stop point. With the device inserted into the vagina, it need not be rotated whilst inside the patient, unlike as in US3664328. Holding the syringe barrel firmly with one hand, a clinician can gently push in the plunger 18 by around 80 mL (figure 14). The membrane 50 will then inflate within the vagina and should be kept fully inflated for about 10 seconds. In this position (figure 15) it will make contact with the vaginal mucosal surface and collect a sample of mucus and suspended material including exfoliated cells onto its exterior surface. The plunger 18 can then be withdrawn by around 80 to 100 mL (figure 16), to fully withdraw the membrane 50 into the interior cavity 28, and the device withdrawn from the introitus (figure 17). The syringe 14 can be unscrewed from the insertion member 12 (figure 18) and the cap 52 replaced securely (figure 19). A sample preservative solution or buffer can be added to the specimen prior to the cap being replaced. The insertion member 12 containing the sample-laden membrane 50 can then be sent for analysis with the membrane 50 protected from contamination within the interior cavity 28 (figure 20). It will of course be understood that many variations may be made to the abovedescribed embodiment without departing from the scope of the present invention.

Claims

1. A vaginal sampling device, comprisingan insertion member having a distal, insertion end, a proximal end and a closable interior cavity;a flexible membrane having an outer, cell sampling surface and an inner surface, wherein said membrane is sealingly attached to the distal, insertion end of said insertion member and held within the interior cavity;such that, in use, pressurisation of the interior cavity to at least a first elevated pressure causes the membrane to emit from the distal end of said insertion member to make contact with the vaginal mucosal surface and pressurisation of the interior cavity to a second reduced pressure causes the membrane to invert and return to the interior cavity of said insertion member;the insertion member having an exterior surface comprising an elongate tip portion with a smooth exterior surface which extends from the distal, insertion end at least as far back as a stop portion comprising at least one transversely-protruding lip extending outwardly from the smooth exterior surface of the tip portion thereby to inhibit insertion beyond the stop portion.

2. A device as defined in claim 1, in which the insertion member comprises:an inner section at least part of which is a hollow tubular section thus defining the interior cavity, anda separate outer sleeve attachable to the inner section to extend around the inner section rearwardly from the distal, insertion end, and which includes the at least one lip.

3. A device as defined in claim 2 in which the outer sleeve also includes the elongate tip portion with a smooth exterior.

4. A device as defined in claim 2 or claim 3 in which the outer sleeve is attachable to the inner section via screw threads provided on an outer surface of the inner section and an inner surface of the outer sleeve.

5. A device as defined in claim 4 in which the screw threads are located proximate the distal, insertion end.

6. A device as defined in any preceding claim, wherein the stop portion comprising a plurality of transversely-protruding lips.

7. A device as defined in claim 6 in which the stop portion comprising a pair of transversely-protruding lips arranged symmetrically either side of the insertion member.

8. A device as defined in any preceding claim, wherein the flexible membrane is elastic and is constructed from a nitrile, latex or rubber based substance.

9. A device as defined in any preceding claim, which further comprises means for pressurisation of the interior cavity, wherein said means are attached to the proximal end of the insertion member.

10. A device as defined in claim 9, wherein said means for pressurisation of the interior cavity are attached to a valve, such as a self- sealing valve, present at the proximal end of the insertion member.

11. A device as defined in claim 9 or claim 10, wherein said means for pressurisation of the interior cavity comprise a source of compressed air or a syringe.

12. A device as defined in any preceding claim, wherein the surface area of the outer, cell sampling surface of said flexible membrane is reproducibly controllable.

13. A device as defined in claim 12, wherein said surface area is controlled by the means for pressurisation of the interior cavity.

14. A device as defined in any preceding claim, wherein the insertion member is adapted to engage with a sealing means, such as a threaded cap, to seal said receptacle.

15. A device as defined in any one of claims 9 to 14, wherein said means for pressurisation of the interior cavity are detachable from the insertion member.

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