Gynaecological samplers

Abstract: An endometrial sampler has an outer catheter 1 and an inner plunger slidable within the catheter. The catheter has a coaxial opening 12 at its tip 11 and two side openings 13 and 14 located diametrically opposite one another close to the tip, the side openings being elongate along the axis of the catheter. The tip 32, 33 of the plunger projects into the tip opening 12 to form a smooth surface to the sampler. An O-ring seal 28 on the plunger 2 is located rearwardly of the side openings 13 and 14 so that suction is applied to both the side openings and the tip opening 12 when the plunger is pulled rearwardly.

Description: This invention relates to gynaecological samplers. Gynaecological samplers are used to take samples from the uterus, cervix or the like, such as endometrial cells lining the uterus. The sampler usually comprises a plastic catheter and a plunger device movable within the catheter. The tip of the catheter is closed and cells are admitted via a single, circular side opening close to the tip when suction is applied by pulling back on the plunger. The problem with such samplers is that it can be difficult to obtain large numbers of cells. Examples of gynaecological samplers are described in, for example: FR 2602414, WO 97/19642, US 4534362, GB 2126100, US 5069225, US 5464022, US 4877037, US4662381, US4396022, US 4340066 and "The Pipelle: A disposable device for endometrial biopsy" by E Cornier, Am. J. Obstet. Gynecol. Jan 1, 1984, pp109-110. DE-A-3539444 describes a sampler having a scraper that extends from the distal end of a suction plunger and projects from an open patient end of a catheter, which has side openings close to its tip. WO-A-9724071 and US 5807282 describe a tissue curette with several tapering side openings. It is an object of the present invention to provide an improved gynaecological sampler. According to the present invention there is provided a gynaecological sampler comprising (a) a catheter having a rounded distal end, a coaxial distal end opening and at least one side opening arranged near the distal end, said or each side opening being elongated along the axis of the catheter, and (b) a plunger with a domed distal tip closely fitting within said distal end opening, said plunger being arranged within and slidable within said catheter from a first forwardmost position to a second more rearward position so that suction is applied to draw material into the catheter through the openings, whereby in said first position the distal tip of said plunger and the distal tip of said catheter form a single continuous convex tip surface, and when the plunger moves from its first position the coaxial opening is unobstructed. The plunger may have an O-ring seal, the O-ring seal being located to the rear of the or each side opening when the plunger is in the first position. The catheter preferably has two side openings in its cylindrical wall and these may be located diametrically opposite one another. An endometrial sampler according to the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of the sampler; Figure 2 is a cross-sectional side elevation view of the sampler; Figure 3 is a cross-sectional side elevation view of the tip of the sampler to an enlarged scale; and Figure 4 is a side elevation view of the tip of the plunger to an enlarged scale. The sampler comprises an outer catheter 1 and a plunger 2 that is slidable axially within the catheter. The catheter 1 is typically about 250mm long and has tubular shaft 10 of cylindrical shape with an outer diameter of about 3mm and an inner diameter of about 2.4mm. The shaft 10 is extruded from a flexible plastics material such as polypropylene and is end formed at its forward, patient end 11 to give it a rounded tip with a coaxial opening 12 of circular shape having a diameter about half the external diameter of the shaft. The shaft 10 is also formed with two further openings close to the forward, patient end tip in the form of side openings 13 and 14. The side openings 13 and 14 are located diametrically opposite one another set back rearwardly from the tip 11 by a distance of about 4mm in a cylindrical region of the shaft 10. Each opening 13 and 14 is elongated axially. being about 2mm wide and 4mm long with rounded ends. The catheter 1 also includes a collar 15 at its rear or machine end 16 into which the rear end of the shaft 10 is fixed. The collar 15 has five internal pips 17 about half way along its length, which help constrict and grip the outside of the shaft 10. The collar 15 has an external annular rib 18 at its forward end and several longitudinal ribs 19, which help provide a secure grip when held between the finger and thumb. A small clearance between the outside of the plunger 2 and the rear end of the shaft 10 allows trapped air to be expelled from the catheter as the plunger is pulled rearwardly. The shaft 10 of the catheter is preferably marked with distance markings (not shown) from its tip. The plunger 2 also acts as a stylet to stiffen the catheter 1 during insertion. The plunger 2 is longer than the catheter 1, being typically about 313mm long and comprises a rear handle 20 and a rod 21 extending forwardly from the handle. The plunger is made from a relatively stiff but bendable material such as polypropylene or nylon. The handle 20 is about 23mm long and comprises a flat plate 22 with a cylindrical boss 23 at its forward end. The handle has gripping projections on its upper and lower surface provided by an axial spine 24 and five lateral ribs 25 on each surface. The rod 21 is solid, being 290mm long and of circular section with a diameter of 2mm along most of its length. The diameter of the rod 21 is increased slightly to 2.2mm along a region 26 extending forwardly from a location 32mm from the tip of the rod. An annular groove 27, with a curved profile, is formed around the rod 21 in the region 26 at a location about 12.5mm from the tip. The groove 27 serves to retain an O-ring seal 28. The diameter of the rod 21 is further increased to 2.35mm along a region 29, which is about 1.5mm long. This enlarged region 29 adjoins a short tapered region 30, about 0.5mm long. The tapered region 30 adjoins a nose portion 31 comprising a rear cylindrical portion 32 and a forward domed portion 33, the diameter of the rear portion being 1.4mm. When the plunger 2 is located in the catheter 1 in its fully forward position, the nose portion 31 projects into the tip opening 12 of the catheter as a close fit and with the domed portion 33 of the rod 21 forming a smooth continuation of the rounded tip 11 of the catheter and closing the opening. Because the plunger 2 extends to the tip of the catheter 1, it acts to stiffen it along its entire length and, in particular, it stiffens it in the region of the openings 12, 13 and 14. The enlarged portion 29 of the rod 21 is a close sliding fit within the catheter land is located forwardly of the side openings 13 and 14. The region 26, being slightly smaller in diameter, allows a small clearance between its outside and the inside of the catheter 1 but the O-ring seal 28 provides an effective, fluid-tight sliding seal with the inside of the catheter at a location to the rear of the side openings 13 and 14 thereby closing the side openings. The sampler is used by inserting its forward end 11 into the uterus with the plunger 2 pushed fully forwardly in the catheter 1. The next step is for the user to withdraw the plunger 2, whilst leaving the tip 11 of the catheter 1 in substantially the same position. As the plunger 2 is withdrawn, it opens the openings 12, 13 and 14 and applies a suction force to them. The plunger 2 is withdrawn to its full extent, as limited by engagement of the enlarged portion 26 with the constriction in the catheter 1 caused by the pips 17 in the collar 15. Engagement with the surrounding tissue limits the rate at which fluid and cells in the vicinity to be sucked into the catheter 1. The patient tip 11 of the sampler is then rotated and rubbed gently backwards and forwards a few times against the endometrium lining the uterus to free endometrial cells. It has been found that the elongated shape of the side openings 13 and 14 significantly increases the effectiveness in loosening of these cells because the longer perimeter of each opening compared with a conventional circular opening causes an abrasive action over a wider area. Also, the use of two openings 13 and 14 on opposite sides further enhances the liberation of cells. The rounded tip 11 of the sampler will also cause detachment of some cells. The suction force applied by withdrawing the plunger 2 sucks the loosened cells into the catheter during this rubbing action. The construction of the sampler has several advantages. In addition to providing an increased liberation of cells, the different orientation of the three openings helps ensure collection of cells from all around the tip of the sampler, leading to an increased number of collected cells. Another advantage is that the large area side eyes enable the sample to be expelled more easily than in previous samplers where it was often necessary to cut off the tip of the sampler before expelling the sample. Also, the elongated shape of the side openings. gives them a greater cross-section and helps reduce damage to the cells that might otherwise be caused by passage into and out of the sampler through a constricted opening.

Claims: A gynaecological sampler comprising (a) a catheter (1) having a rounded distal end (11), a coaxial distal end opening (12) and at least one side opening (13, 14) arranged near the distal end (11), said or each side opening (13, 14) being elongated along the axis of the catheter, and (b) a plunger (2) with a domed distal tip (31, 33) closely fitting within said distal end opening, said plunger being arranged within and slidable within said catheter from a first forwardmost position to a second more rearward position so that suction is applied to draw material into the catheter through the openings (12, 13, 14), whereby in said first position the distal tip of said plunger and the distal tip of said catheter form a single continuous convex tip surface, and when the plunger moves from its first position the coaxial opening is unobstructed. A sampler according to Claim 1, characterised in that the plunger (2) has an O-ring seal (28), and that the O-ring seal is located to the rear of the or each side opening (13 and 14) when the plunger is in the first position. A sampler according to Claim 1 or 2, characterised in that the catheter (1) has two side openings (13 and 14). A sampler according to Claim 3, characterised in that the side openings (13 and 14) are located diametrically opposite one another.

Inventors: MORRIS EDWARD PATRICK, RIDOUT PAUL BENJAMIN, MORRIS, EDWARD PATRICK, RIDOUT, PAUL BENJAMIN
Applicants: MORRIS EDWARD PATRICK, SMITHS GROUP PLC, MORRIS, EDWARD PATRICK
Application year: 1999
Main classification: A61B10
IPC codes: A61B10