Method of manufacturing coated needle electrodes

#The current invention relates to a method of manufacturing coated needle electrodes. Coated needle electrodes are typically used for sensing electrical potentials in living tissue or for conducting electrical energy to such tissue. Needle electrodes are used in many different forms of therapy and/or diagnostic procedures. Two non limiting examples are tissue ablation and electromyography.

#Coated needle electrodes generally comprise an elongated electrically conductive metallic shank which is sharpened at one end by grinding. Needle electrodes typically also have connection means attached to the other end for connecting said needle electrode to external electronic equipment. The metallic shank of the electrode is normally covered by an electrically insulating material so that only a small metallic area near the sharp tip will be in electrical contact with the tissue, hence the name “coated needle electrode”.

#Needle electrodes are commonly manufactured by first cutting a metallic wire or tube to a desired length. The needle shank is then held fast near one end while the entire free shank is coated with an insulating material by spraying or dipping followed by curing and/or sintering of the coating. After the needle shank is coated, the coated tip is ground sharp whereby the insulating material is simultaneously removed from the electrode tip. Finally the connection means is electrically attached to the uncoated blunt end of the needle shank.

#In the following, the invention will be described in greater detail with reference to embodiments shown by the enclosed figures. It should be emphasized that the embodiments shown are used for example purposes only and should not be used to limit the scope of the invention.

#FIG. 1 illustrates a schematic representation of an apparatus for performing the coating step of the manufacturing method.

#FIGS. 2-4 show schematic sectional views of a suspension head and a loading fixture at three different points of the loading process.

#FIG. 1 shows one embodiment of an apparatus used in a method for manufacturing coated needle electrodes according to the invention. It is to be noted that the figures show the embodiments schematically and many of the details are not shown. The person skilled in the art should easily be able to fill in the missing details.

#In the apparatus 1, a suspension head 2 is detachably fixed to a slide saddle member 3 which is slideably mounted on vertical guides 4 allowing the slide saddle member to linearly move up and down. The movement of the slide saddle member 3 is controlled by a linear drive screw 5. A servo motor drive 6 controls the direction and the speed of the movement. The frame of the vertical guides 4 is mounted on a horizontal frame member 7.

#A container 8 filled with coating fluid 9 is supported by a plate 10 which is connected to the horizontal frame member 7 by means of a threaded shaft 11 and a threaded bushing 12. Via the threaded shaft and threaded bushing the vertical position of the container 8 can be adjusted. This can be used to compensate for changes in the fluid level in the container.