4,561,445 DATED DECEMBER 31, 1985

ELONGATED NEEDLE ELECTRODE AND METHOD OF MAKING SAME

The purpose of this invention is to add additional bevels on EMG needle electrode tips which results in decreased pain for our patients during the procedure and thereby increasing accuracy of diagnosis. The method of making the needle may be practiced not only to make needles (or needle electrodes) initially but also to regrind or sharpen them when necessary. The improved needle (and needle electrode) of the present invention has a point and a bevel which are of increased resistance to breakage and which are of substantially increased sharpness for easier and less painful needle insertion. The tip includes a plurality of tapered or beveled surfaces which allow the inserted needle to more cleanly cut tissue during rotation thereby reducing the discomfort of electromyography.

The tip of the needle (or needle electrode) of the present invention is multifaceted and is formed by the intersection of a plurality of bevels. Thus the tip is laterally supported by the beveled surfaces against forces applied from several directions. The peripheral edges of each bevel or facet reduce patient discomfort by increasing the lateral sharpness of the needle electrode. The needle electrode can thereby cut tissue without undue tearing or stretching of the tissue.

In a preferred embodiment, an improved electromyography needle electrode is provided having inner and outer coaxially positioned electrodes. At least one bevel or facet is formed on the exposed end of the electrode. Since the bevel is at an angle to the longitudinal axis of the shank, the sensitivity of the needle electrode is improved by the increased amount of exposed surface area. Thereafter, according to the principles of the present invention, additional beveled surfaces are formed on the exposed end of the electrode to not only increase the amount of exposed surface area but to provide for more smooth cutting of tissue as the needle is rotated.