US 2869550 A
Description (OCR text may contain errors)
Jan. 20, 1959 i D. KURTZ 2,869,550
` SURGICAL NEEDLE:
Filed Jaf 4., 1956 IN VENTOR ATTORNEYS B'Y mmy@ 2,869,550 SURGCAL NEEULE Leonard D. Kurtz, Woodmere, N. Y., assignor to J; A. Dekna'tel & Son', Inc., Queens Village, N. Y., al com- Daily ,ApplicatioriV January 4, 1956, Serial No. 557,326
` s Claims. (c1. 12s-33s) This invention relates to a surgical needle` and more particularly` toa needle which may be used for all types of suturing. Specifically, the invention herein disclosed is la needle of maximum sharpness and strength and yet which is` provided with a single cutting edge to minimize the possibility of tearing tissues'. A y
By providing a needle with exceptional sharpness, `considerably less force ismrequired to cause the needle to' pass through tissue. Thus, since one' needle need not withstand as much force, smaller needle diameters may be used and consequently the hole produced is smaller.
Heretofor'e, surgical needles have been of two types, namely, a cutting needle which was used for suturing the tougher tissue and a non-cutting needle which was used in suturing the softer, more pliable tissue. The non-cutting needle passes through the tissue with the lateral surface of the needle pushing aside any blood vessels which may be in the path of movement of the needle. The necessity for the two types of needle has been obviated by the present invention in which the critical factors involved in the manufacture of surgical needles have been found and suitable working limits have been set for these critical factors.
One of the prime consideratio-ns in the design of surgical needles is in minimizing trauma. In surgical suturing techniques this is achieved by providing the smallest possible opening for the passage of thread through the tissues and by using the sharpest possible needle to prevent bruising delicate tissues. There are, ofcourse, other considerations which conflict with these factors. It is important that the point of the needle have sufcient strength to prevent any possibility of the needle breaking olf or bending while in use. Furthermore, the possibility of the needle tearing through the tissues must be minimized.
Prior art surgical needles utilized presses to form the point on the needle and such pressing caused distortion of the cutting end of the needle so that, in effect, the cutting end of the needle had a larger diameter than the round portion that followed. The disadvantage in such structure is readily apparent. A larger opening would be provided than is essential for the size of thread. Prior art needles were provided with a plurality of cutting edges which increased the possibility of tissue tearing. A plurality of cutting edges were provided in the belief that the amount of pressure required to pass the needle through a tissue would be decreased by increasing the number of cutting edges. However, surprisingly enough, a single cutting edge provides a much more efficient cutting surface and two to three times the sharpness is achieved with the present invention. In general, the prior art did not appreciate the critical factors involved in the manufacture of surgical needles.
According to the present invention, a surgical needle is provided with a single cutting edge which is fomtl by 2` grinding. Thus, the diameter of the point does not be-y come larger than the diameter of the rest of the needle. For a maximum degree of sharpness and yet maintaining sufficient metal in the pointl to prevent bending, it
An object of the present invention ijs to provide aiV surgical needle which has a maximum degreegof sharpness so as to minimize trauma and yet the needle possesses suicient rigidity.
Another object of the present invention is to provide a surgical needle having a single cutting edge which is formed by a grinding operation.
Still another object of the present invention is to provide a surgical needle in which the angles ofslope and sharpness lie within a predetermined range.
Other objects and many of the attendant advantages will becomel apparent upon consideration of the following detailed spec'ication when taken in connection with the accompanying drawing wherein:
Fig'. l is a perspective View of a surgical needle made in accordance with the present invention;
Fig. 2 is an enlarged view of the point of the needle shown in Fig. 1.; A
Fig. 3 is a sectional view along the liner lie-3. of Fig. 2; and
Fig. 4 is a sectional view along the line 4--4 of Fig. 2.
Referring now to the drawing wherein like numerals indicate like parts throughout the several views, there is shown at 1 in Fig. 1 a surgical needle to which surgical thread 2 is attached by any suitable means as by swaging as at 3. The thread may also be retained by drilling the end of the needle and inserting the thread and squeezing the needle and thread together. The point of the needle is provided with two at faces as shown at 4 and 5 so that the cutting edge 6 extends laterally when the needle is in use. It is, of course, possible to orient the cutting edge in any desired plane and obtain the advantages of a single cutting edge as brought out hereinbefore.
By having the cutting edge of the needle laterally disposed and the flat faces on the upper and lower surfaces of the needle, the possibility of tearing tissue is minimized. Furthermore, by forming the point and the two flat surfaces by a grinding operation it is assured that no larger diameter than the diameter of the round portion ofthe needle will be present in the point.
The angle which is identified as the angle B in Fig. 2 is termed the angle of slope. This angle determines the rate at which the tissues are cut to the diameter of the needle. The angle shown as angle C in Fig. 3 is termed the sharpness angle. This angle actually determines the sharpness of the lateral cutting edge. The smaller the angle C, the sharper is the cutting edge. However, it is apparent that if the sharpness angle is made too small, there is insufficient metal in the point to give the point the necessary strength. Similarly, the angle of slope must be minimized to provide for ease in passage of the needle through tissue and yet must be suflicently large to preserve metal at the point to give the needle rigidity. It has been found that the sharpness angle and angle of slope may lie within a range of from ten degrees to sixty degrees and give satisfactory results. Experiments have been conducted in which various angles of slope and sharpness were used and the force necessary for the needle to penetrate a membrane was measured. The following is a result of that investigation:
.045l Wire Diameter .026 Wire Diameter .016 Wire Diameter B C Force B C Forc B C Force Oz. g Oz. Oz.
It can be seen that satisfactory results are obtained in f which angles of slope and sharpness lie within a range. of from ten to sixty degrees. In connection. with the above table, it will be noted that the penetrating force increases appreciably when both the angle of sharpness` and the angle of slope reach larger values.
It is also to be noted that the sharpness of the needle is more sensitive to the slope angle than to the sharp# ness angle. That is to say, the penetration'force increases to la greater degree by increasing the angle of slope B than with an increase in one angle of sharpness C.
Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. What is claimed as new and desired to be secured by Letters Patent is:
1. In a device of the class described, a curved needle, said needle having a single cutting edge formed Iby a pair of substantially at surfaces, the single cutting edge being disposed in a plane at .to a plane passing through the center line of the curved needle, said surfaces forming at the cutting edge a sharpness angle, an angle of slope formed at the point of the needle, the angle of slope and the sharpness angle being within the range of 10 to 60 degrees. Y
2. In a device of the class disclosed, a curved surgical needle having a point, said point formed by a pair of substantially flat surfaces angularly related and disposed on the inner and outer curved surfaces of the needle to form a single cutting edge and an angle of slope at the point, the angle of slope and the sharpness angle formed by the intersecting surfaces of the cutting edge lying within the range of 10 to 60. l
3. A surgical device comprising a needle having a curvature, the cutting edge of the needle formed by a pair of substantially plane angularly related surfaces, the cutting edge being disposed on a surface of the needle spaced with respect to the inner and outer curved surfaces thereof, said surfaces forming at the cutting edge a sharpness `angle, an angle of slope formed at the point of the needle, the angle of slope and the sharpness angle being within the range of 10 to 60.
References Cited in the tile of this patent UNITED STATES PATENTS 1,321,011 Cones` Nov. 4, 1919 1,592,535 Morton July 13, 1926 2,581,564 Villegas t Jan. 8, 1952