This invention relates to medico-surgical needle assemblies of the kind having a rigid tubular shaft with a bore extending along its length, a sharply pointed cutting tip at its forward patient end and a hub at its rear machine end.

Amniocentesis is a procedure carried out on pregnant women to detect chromosomal abnormalities in an embryo. A needle is inserted through the patient's abdominal wall, through the wall of the uterus and then into the amniotic sac. A small volume of amniotic fluid is then sucked through the needle for subsequent testing. The procedure is usually carried out under ultrasound observation but the relatively small diameter of the needle can make it difficult to see the needle especially at certain angles.

Medico-surgical apparatus employing some form of imaging means, such as a video camera chip usually require some form of illumination, such as an LED or the like mounted adjacent the video camera chip. There can be problems providing such a light source because of lack of space, or the light source that can be used does not have a suitable optical output.

It is an object of the present invention to provide alternative medico-surgical apparatus.

According to one aspect of the present invention there is provided a medico-surgical needle assembly of the above-specified kind, characterised in that the needle includes imaging means towards its forward end for providing an image output during use of the assembly.

The imaging means preferably includes a video camera chip for providing a video output during use of the needle. The imaging means may be fixed with the needle at a location that allows fluid to flow along the bore of the needle during use of the imaging means.

Preferably the imaging means is located in a recess in the bore of the needle. Alternatively, the imaging means may be removably mounted in the bore of the needle and be removable from the needle after placement of the needle tip. The imaging means may include a light source. The imaging means may include a cable extending along the bore of the needle. The shaft of the needle may be of a metal. Alternatively, the shaft of the needle may be of an optically- transmissive material, the assembly including a light source coupled with the shaft towards its rear end such that light from the source is supplied along the shaft to its patient end. The assembly may be an amniocentesis needle assembly, the cutting tip at the patient end of the shaft being adapted to penetrate the amniotic sac, and the hub at the machine end of the assembly connected with a suction device such that material in the amniotic sac can be withdrawn along the shaft of the needle. The needle shaft may be echogenic.

According to another aspect of the present invention there is provided medico-surgical apparatus including imaging means mounted towards one end of an elongate support member and a light source located towards an opposite end of the support member, characterised in that the support member is of an optically-transmissive material such that light produced by the light source is channelled along and within the support member towards the one end to illuminate the field of view of the imaging means.

The support member may be a needle with a cutting tip at the one end.

According to a further aspect of the present invention there is provided a method of using a needle having imaging means towards a forward cutting end tip, the imaging means being connected with a display screen on which is provided a display representation of the field of view of the imaging means, including the steps of inserting the needle tip into a patient, monitoring the image on the display screen to help direct the needle tip to the desired location, supplying or withdrawing material along a bore of the needle when the image indicates that the needle tip is at the desired location, and subsequently withdrawing the needle.

The needle may be echogenic, the method including the step of monitoring an ultrasound image of the needle as well as the image from the imaging means during insertion. The ultrasound image may be monitored initially until penetration of the amniotic sac, the image from the imaging means being monitored during penetration and extraction of amniotic fluid.

An amniocentesis needle assembly 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 side elevation view illustrating the assembly:

Figure 2 is an enlarged cross-sectional side elevation view showing the patient end of the needle in greater detail;

Figure 3 is an enlarged cross-sectional side elevation view of the patient end of an alternative needle; and

Figure 4 is an enlarged cross-sectional side elevation view of a second alternative needle.

With reference first to Figures 1 and 2, the assembly shown includes an amniocentesis needle 1, a syringe 2 for withdrawing a sample from the needle, and a display monitor 3 for visually monitoring the procedure.

The needle 1 has a straight tubular shaft 10 of a rigid metal and a circular section, with a bore 11 extending along its length. At its rear end the shaft is bonded with a plastics hub 12 having a female luer bore adapted to receive the nose 20 of the syringe 2, or other suction device, in sealing engagement with the hub and the bore 1 1 of the needle. The shaft 10 may be arranged to have enhanced echogenicity, that is, ultrasound visibility, such as by texturing the shaft surface, or forming grooves or the like on its surface, or by the inclusion of gas bubbles within the material of the shaft in a well-known way. The forward, patient end 13 of the shaft 10 is bevelled and sharply pointed to provide a cutting, penetrating tip 14 to the needle 1. The wall of the shaft 10 at its heel 15 is cut away to provide a recess 16 in which is secured a video camera chip 17 including a light source such as an LED 27.

The chip 17 has the usual imaging array, drive and processing circuits, and some form of lens to focus the desired field of view onto the chip. Cables 18 from the chip 17 pass along the bore 1 1 of the shaft 10 and extend out of the hub 12 where they are terminated by an electrical connector 19. The connector 19 connects with a mating connector 30 at one end of a cable 31 extending to the monitor 3. The monitor 3 has a display screen 32 on which a representation of the field of view of the chip 17 is displayed. The monitor 3 may also have an additional input 33 for a conventional ultrasound transducer 34 so that two separate images can be displayed adjacent one another on the screen 32 from the video chip 17 and the ultrasound transducer. In this way, the clinician can monitor both images at the same time so that he can accurately position the tip 14 of the needle 1 and penetrate the amniotic sac with a reduced risk of damage to the embryo. Even when the ultrasound image is only poorly visible, such as because of an unfavourable angle of the needle 1 relative to the transducer 34, the clinician still has the benefit of the image provided by the video chip 17.

Figure 3 shows a modified needle 1 ' with a shaft 10' similar to that of the needle 1 shown in Figures 1 and 2 except that the patient end of the shaft 13' is not cut away to form a recess for the video chip. Instead, the video chip 17' with its light source 27' is removably mounted within the bore 1 1 ' of the shaft 10'. In this configuration, the needle Γ is used normally while observing the video output on the monitor until the amniotic sac is penetrated. Once this has happened, the video chip 17' is removed by pulling the cables 18' so as to pull the chip rearwardly and then remove it from the bore 1 . After the video chip 17' has been removed suction can be applied to the shaft 10' to remove a sample of amniotic fluid in the amniotic sac. This arrangement has the advantage of enabling a larger video chip to be used in a needle of a given diameter so gives greater flexibility in choice of components. This may enable improved imaging, better lighting or lower cost. The invention is not limited to amniocentesis needles but could be used with other needles.

A further modification is shown in Figure 4. This shows an arrangement where the video chip 17" is mounted in a recess 16" in the wall of the shaft 10" at its patient end 13", although it could have a removable video chip as described with reference to Figure 3. The needle 1 " of Figure 4 differs from those shown in Figures 1 to 3 in that, instead of having a metal shaft, the shaft 10" is made of an optically-transmissive material such as a plastics, glass, crystal or the like capable of transmitting optical radiation suitable for illuminating the field of view of the video chip 17". The shaft 10" is preferably moulded or extruded from the optically-transmissive material as a single, solid, unitary body to maximise light transmission along the shaft. The needle 1 " includes a light source 27" mounted towards the rear end of the shaft 10", such as within the hub 12" with the source in optical communication with the shaft so that light from the source is channelled and transmitted along the shaft to emerge at the patient end 13" and thereby illuminate the field of view of the video chip 17". By mounting the light source 27" at the rear end of the needle 1 " instead of at the tip, the source can be larger and provide an increased level of illumination.

The arrangement of an optically-transmissive needle shaft or other elongate support member and a light source mounted at the rear end could be used in other medico-surgical apparatus as well as in amniocentesis needles.