CA2094136C - Blunt tip surgical needle - Google Patents

Abstract

A surgical needle (10) for use in suturing non-cutaneous soft tissues of the body. The surgical needle includes a needle shaft (11) and a needle tip (12) formed of a rigid material suitable for use inside tire body. The needle tip has a body portion (14) integrally formed with and extending from the needle shaft and is tapered along its length. The needle tip is further provided with a blunt head (16) which together with the body portion defines a continuously smooth outer surface lacking any sharp cutting edges. The blunt head is adapted to penetrate muscle and fascia, muscle alone, adipose, pericostal tissue and other non-cutaneous soft tissues of the body while at the same time preventing skin penetration of the gloved hand of an operator.

Description

2 P"CT/US91/O~OS4 ~~~~130 BLUNT TIP SURGICAL NIEFDLE
BACKGROUND OF THE INVENTION
Field of the Invention:
The present invention relates generally to the field of surgical instruments and, mare specifically, to surgical needles for suturing wounds.
Description of the Art:
In recent years, there has been an increasing awareness of the problems associated with accidental sticking of medical personnel with suturing and syringe needles. Before the advent of biological warfare contaminants and the spreading of infectious health hazards such as hepatitis B
(HBV), human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS), the consequences of sustaining a needle stick wound were not considered serious. However, the knowledge that infectious diseases such as the AIDS virus can be spread by an accidentally inflicted needle-stick from a contaminated needle.
administered to a person having the AIDS virus has done much to change this belief. Accordingly, there has been an increasing amount of activity in the area of addressing this problem. For example, one prior art needle assembly contains a blunting member which is movable; either by fluid flow through the needle or by mechanical pressure, from a retracted position in which the blunting member does not interfere with the puncture tip of the needle, to an extended position attained after use in which the blunting member wa g2iosa~z ~c~rius~mo~osa ~~~~1~0 extends beyond the punture tip and thereby blunts the needle. The prior art discloses further examples of shield or guard type assemblies for syringe needles.
While the devices disclosed above and other similar type devices may be useful for hypodermic syringe needles which are intended to be disposed of after a single "stick", it is not a practicable solution for use u~xth surgical needles since such needles must make repeated "sticks" into the body. While surgeons are highly trained and skilled individuals, the possibility of an accidental stick from a surgical needle is still present. Even a highly skilled surgeon can eventually became tired or, as in trauma situations. in a hurry at the end of a long operation and thus more prone to such an occurrence. Then too, it is not uncommon that a less experienced individual in the operating room team is assigned to close the wound.
The present invention is intended to decrease the potential transmission of all infectious agents, including those referred to above, in situations where accidental needle,stick is the means fox such transmission.

SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a surgical needle for use in suturing non-cutaneous soft tissues of the body, comprising: a needle shaft; and a needle tip, said needle shaft and needle tip intergrally formed of a rigid material suitable for use inside the body and containing no fluid passages therethrough, said needle tip having a body portion integrally formed with and extending from said needle shaft, said body portion being tapered along the length thereof, raid needle tip further having a blunt head adapted to penetrate muscle and fascia, muscle alone, adipose, pericostal tissue and other non-cutaneous soft tissues of the body while preventing skin penetration of the gloved hand of an operator.
The present invention is a surgical needle for use in suturing non-cutaneous soft tissues of the body. In .a preferred embodiment thereof, the present invention comprises a needle shaft and a needle tip formed of a rigid material suitable for use inside the body. The needle tip has a body portion integrally formed with and extending :from the needle shaft. The body portion is tapered along the length thereof. The needle tip is further provided with a blunt head adapted to penetrate muscle and fascia, muscle alone, adipose, pericostal tissue and other non-cutaneous soft tissues of the body while at the same time decreasing potential skin penetrati~~n of the gloved hand of an operator and operating personnel .such as surgeons, surgeon assistants, scrub and circulating nurses, fabric care and housekeeping personnel.
As additional features, the blunt head may have a part spherical shape and a vertex which forms a portion of the part spherical shape. Further, the blunt head may have -3a-a diameter of curvature which is in a range from about 25%
to 62% of the diameter of the needle shaft and the needle tip may be formed so as to have a continuously smooth outer surface lacking any sharp cutting edges.
Accordingly, it is an object of the present invention to provide an improved surgical needle for use in suturing muscle and fascia, muscle alone, adipose, pericostal tissue and other non-cutaneous soft tissues of the body while at the same time significantly decreasing the probability of skin penetration of the gloved hand of an operator.
Related objects and advantages of the present invention will become more apparent. by reference to the following figures and detailed description.

wo 9zio8arz Pcrms9mogosa ~~~~~1~~~

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph showing the relationship between penetrationforce and needle bluntness using data obtained from Table I.

FIG. 2 is a graph showing the variation in difference in resistance to penetration between gloved plantar skin and abdominal ectus muscle as a function of needle bluntness r using data obtained from Table III.

FIG. 3 is a graph showing the variation in average penetrationforce as a function of needle bluntness using data obtained from Table III.

FIG. 4 is a side view of a preferred embodiment of the surgical edle of the present invention.
ne FIG. 5 is an enlarged fragmentary view of the tip portion of the surgical needle of FIG. 4.

FIG. 6 is an enlarged cross-sectional view taken along lines 6--6 in Figure 4.

FIG. 7 is an alternative emf?odiment of the enlarged cross-sectional view taken along lines 6--6 in Figure 4.

FIG H is an enlarged cross-sectional view taken along lines 8--8 in Figure 4.

PCf / US9l /08054 wo 9z/os4~z DESCRIPTION OF THE PREFERRED EMBODIMENT
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
As used herein, the term "bluntness" is intenctect to rexer to the relation between the diameter of curvature of the needle point or vertex to the diameter of the needle shaft.
For comparison purposes, this relationship is expressed as a percentage. As an example, a needle having 50°s bluntness is intended to describe a needle having a diameter of curvature at the vertex which is half the diameter of the needle shaft. The term "diameter of curvature" as used herein describes the hygothetical diameter of a fully spherical surface coincident with the part spherical surface which forms the vertex, or forwardmost point, of the needle. Thus, a totally sharp needle, i.e., a needle having Oo bluntness, has zero curvature present at the needle vertex.
A number of tests were conducted to determine whether there existed a blunt needle point configuration which would permit relatively easy penetration of soft non-cutaneous body tissues while providing increased protection against an unintended stick of the gloved hand of the operator. These included tests to determine the penetration force as a function of "bluntness" in muscleffascia and in gloved palrnar skin.
In a first series of test , four groups of test results WO 92/08412 Pt_°T/1JS91/0805A

were obtained corresponding to the following four test specimens: (1) abdominal rectos muscle/fascia, (2) gloved palmar skin, (3) abdominal rectos muscle/fascia vs. gloved plantar skin, and (4) intercostal muscle. In each group of tests, eight needle point configurations were tested having a bluntness of 0%, 25%. 37%, 50%, 62%, 75%, 87%, and 100%. A
sample set of six needles per each configuration were used for each of the first, second and fourth groups of tests, making a total of 48 needles for each of these groups of tests. In the third group of tests, a sample set of twelve needles was used for each needle configuration, making a total of 96 needles for this test group. All needles were type T-20 surgical needles manufactured by the Davis & Geck Division of American Cyanamid Company of Danbury, Conn., U.S.A. having a length of 1.891 inches, a wire diameter of .050 inches, and a curved shape having a radius of curvature along the needle shaft of 0.656 inches and an included angle of 165 degrees.
The first group of test results far the abdominal rectos muscle/fascia was conducted as follows. The skin overlying the abdominal fascia of a single cadaver was opened and retracted. The supra-umbilical abdominal rectos muscle wzth its anterior and posterior sheaths was then excised from the cadaver. Using this specimen, the farce of penetration was measured for each of the needles in the sample. A total of three passes were made for each needle. In each pass, penetration was made away from the midline of the specimen so that the penetration sequence would always be fascia, muscle, then fascia.
In the second group of tests, skin from the palms of the same cadaver used in the first series of tests was harvested: The area harvested was bounded proximally by the skin crease at the wrist and distally by the base of the digits. A standard latex procedure glove was placed aver the skin specimen in order to simulate unintended puncture of the ~'VO 92108412 PCT/US91/08Q54 surgeon's hand. The penetration sequence was glove, epidermis, dermis, and lastly, the back side of the latex glove. As with the first group of tests, the force of penetration was measured for each of the needles in the sample, with a total of three passes being made for each needle.
The goal in the third group of tests was to directly compare the penetration force of gloved skin as compared to that of abdominal rectus muscle/fascia using the same needle. Since all usable palmar skin had been harvested from the test cadaver in performing the previous group of tests and another suitable cadaver was unavailable, plantar skin was harvested from the test cadaver's feet. This skin is similar to the skin of the palm in that both are thick skin areas. Only the central non-weight bearing portion of the plantar skin was used. The rectus muscle and fascia was harvested from the same test cadaver from the umbilicus to just superior to the pubic bone. The rectus muscle/fascia tissue was penetrated first, followed by the gloved plantar skin. In order to assess the difference in penetration force of palmar skin versus plantar skin. several passes were made through some remaining palmar skin after the plantar skin had been penetrated. The results obtained indicated that the penetration force was approximately the same for the two skin specimens using the sharp (0o bluntness) needles, with the plantar penetration force increasing as the bluntness fo the needle increased (approximately twice the penetration force was necessary with a 62% dull needle). Again, the force of penetration was measured for each of the needles in the sample. In this group of tests. one pass was made into both specimens with each needle.
For the fourth group of tests, intercostal muscle was harvested from the same cadaver from interspaces 3 through 5 at the mid-clavicular line. The specimen blocks also ~35 consisted of the pleural lining of the chest (parietal WO 92/08412 PC.'T/US91/08054 -s-pleura). The force of penetration was measured for each of the needles in the sample, with a total of three passes being made for each needle.
Table 1 lists the results of each of the four groups of test results in this first series of tests. Each needle is identified in the table by the letter "D" prefixed by a number indicating the testing order. The penetration force is expressed in grams.

WO 92/0412 1'CT/US91/08054 ~AB~E I
Croup 1 results (Abdominal Rectos Fascia/Musclel:
0% 25% 37%

4D 80, 220, 80 3D 3GU, 680, 6D 880, 600, 7D 120, 120, 23D 840, 760, 9D 920, 2I20, 19D 40, 80, 120 14D 640, 600, 12D 720, 840, 3UD 80, 120, 80 20D 60U, 520, 26D 1160, 760, 38D 80, 80, 80 31D 680, 720. 27D 520, 840, 40D 4U, 80, 120 36D 84U, 640, 4ID 800, 600, 50% 62%

5D 920, 960, 2D G40, 720, 6U0 I1D 1560, 2000, IOD2040, 1200, 25D 2040, 1160, 18DI800, I720, 28D I800, 1000, 24D1240; 2520, 32D 720, 1120, ,. 29D2560, 920, 840 42D 920, 1400, 39D2200, 1,52U, 75% 87% I00%

8D 2520, 2440, 15D 2680, 2280, ID 2920, 1200, I7D 1520; 2880, 21D 1760, 1960, 16D 2400, 2760, 22D 2440, 1320, 34D 2480, 2260, 23D 1920, 2680, 33TJ 2000, 2840, 35D 1760, I560, 37D 2280, 3000;

46D 2120, 2760, 43D 2640, 2800, 44D 2520, 1880, 47D 2620, 2720, 45D 1680, 2760, 48D 2920, 2440, WO 92108412 paCT/US91/08054 L S
group 2 res .~lts_( loved P~Jm rte. 'ri 0% 25% 37%

8A 300, 500, 9A 900, 800, 4A 800, 1200, 10A 200, 200, 14A 300, 800, 19A 800, 700, 5 11A 6U0, 700, 15A 7U0, 700, 23A 1200, 1300, 12A 400, 400, 44A 800, 800, 32A 1000, 1000, 27A 300, 700, 61A 600, 800, 33A 1200, 2000, 31'1 400, 600, 63A 900, 1400, 35A 900, 1800, 37A 400, 700, 65A 800, 800, 42A I600, 1500, 6U0 800 ~ 900 10 66A 200, 300, 69A 1300, 1300, 45A 800, 800, 73A 100, 200, 74A 800, ?00, 46A 1300, 1800, 83A 200, 300, 97A 500, 5U0, 56A 900, 900, 85A 500, 400, 81A 700, 600, 59A 1000, 900, 88A 2UU, 200, 91A 500, 600, 94A 900, 900, 50% 62%
1A 1840, 2240, 1600 16A 1500, 1300, 6A 1I00, 1200, 1100 21A 1500, 2200, 18A 1500, 1500, 1300 24A 2000, 1700, 26A 1400, 1800, 1300 29A I500, I900, 34A I700, 1600, 1600 47A 2400, 2300, 48A 2600, 1500, 2000 49A 3000, 2600, 54A 1400, 2300, 2200 52A 1200, 1100, 57A 900, 2300, 1600 55A 1400, 1200, 68A 1800, 1400, 1500 58A 1300, 1900, 75A 1200, 1UOU, IZ00 60A 9U0, 1200, IOUO

79A 1100, 1000, 1400 82A 1700, 1500, 80A 1600, 1600, 2000 96A 2200, 2000, 75% 87% 100°!0 2A 2900, 2800, 2700 5A 3600, 2300, 3600 22A 2400, 3000, 2900 3A 1600, 4500, 3900 13A 2700, 2400, 2300 25A 3100, 3600, 2300 7A 1800, 2200, 2700 17A 2700, 2900, 3300 30A 3400, 2800, 5600 20A 2200, 3200, 3200 28A 4600, 3100, 3000 40A 6000, 5100, 4000 36A 4800, 4500, 4200 39A 3900, 3000, 3200 43A 4900, 3200, 3400 38A 3200, 3500, 3600 4IA 3300, 3500, 3400 5IA 3100, 3000; 2900 50A 1900, 2400, 2000 64A 3900, 3200, 5500 62A 4900, 3100, 2100 53A 3100, 2200, 3100 76A 2400, 2600; 2800 67A 4900, 4500, 2900 71A 1400, 2300, 2000 84A 3800, 2800, 2700 70A 2800, 3300, 3200 72A 21 U0, 1800, 2600 89A 2200, 2000, 2200 87A 4200, 3200, 3000 78A 9800, 2000, 2300 93A 2300; 3000, 2100 90A 2500, 3400; 2700 86Paa. 2100, 22U0, 3500 95A 2400, 2900, 2800 92A 2800, 2400, 3300 WrO 92/08412 ~ ~ PC'T/US91/08054 r m 'i ~ fAbdomina,Rec~~~Muscle/FasczB_v~~ Glov Plantar Skiol:
R~:~lt o 0% 25io 37%

8B 50, 7B 550, 12006B 500, 800 9B 50, 10B 450, 145012B 350, 1600 19f3 50, 21B 350, 900 16.8 Ei00, 1350 28B 150, 37B 700, 115020B 450, 1200 53B 20U, 38B 450, 110024B 550, 1350 54B 50, 51B 250, 115030B 450, 1.250 73B 100, 56B 300. 150 39B 350, 1050 75B 50, GOB 500, 1600458 Ei5U, 1400 77B 50, 65B 550, 140048B 350, 1300 90B 50, 83B 350, 110059B 800, 1750 89B 100, 84B 700, 120068B 700, 1200 91B 50, 85B 40U, 110092B 400, 1200 50% 62%

1B 750, 2600 2B 650, 2450 5B 600, 3050 11B 500, 2850 13B 450, 1800 22B 850, 2400 25B 600, 2400 34B 750, 2750 328 Z50, 2650 36B 850, 2500 35B 35U, 1150 4J.B 900, 2150 40B 1000, 4GB GOU, 3100 52B 500, 2450 61B 850, 2500 67B 550, 1900 G7B 1100, 3750 , 70B 1400, 79B 5U0, 3350 78B 600, 2250 B:I.B 700, 3300 87B 750, 2300 94B 250, 3000 75% 87% 100%

48 350, 3300 15B 700, 4850 3B 750, 5000+

14B 1500, 3000 26B 800, 5000+ 17B 700, 5000+

18B 1150, 3600 29B 300, 4150 24B 1800, 5000+
, 23B 400, 3750 31B 900, 5000-~4ZB 300, 5000* ..

33B 1400, 4250 44B 1050, 4900 49B 1000, 5000+

43B 950, 3600 578 1350; 5000+62B 1550, 5000+

47B 1100, 4750 58B 1300, 5000+64B 75U, 5000+

50B 700, 2150 69B 1300, 2950 74B 1200, 5000+

55B 900, 4450 71B 2550, 4500 76B 600, 5000+

66B 900, 4950 80B 2350, 5000+82B 1000, 500G+

728 1900, 4500 88B 900, 5000+ 86B 1550, 5000+

93B 1050, 4650 96B 1700, 4450 95B 1150, 5000+

w0 9z7os4~z _12_ P~'t'/US91/08054 Grou p 4 Results rcosta.l.Fascia/Musele) flnte 0% 25.'0 37%

21C 40, 80, 80 9C 720, 980, 13C 800, 1000, 24C 40, 40, 80 15C 360, 200, 16C 320, 440, 36C 160, 200, 29C 200, 480, 20C 600, 440, 47 C 80, 80, 80 34C 520, 240, 30C 200, 360, 43C 80, 80, 40 37C 400, 520, 31C 4UU, 560, 20U , 320 48C 40, 80, 40 39C 400, 240, 45C 440, 480, 50% 62%

8C 1040, 2440, 520 3C 880, 640, 600 14C 720, 480, 600 lOC 480, 480, 880 22C 400, 40U, 760 11C 1200, 880, 1600 27C 400, 32U,~ 720 17C 8UU, 840, 840 29C 520, 480, 4U0 26C 720, 480, 440 42C 360, 440, 480 4UC 400, 440, 72U

?5% 87% 100%

1C 1000, 88U; 5C 1800, 920, 4C 960, 1960, 2C 1200, 600, 7C 1760, 2400, 32C 1600, 760, 6C 92U, 2200, 23C 520, 6U0, 35C 1840, 1800, 560, 2560, 28C 720, 2520, 44C IIZU, 720, 22C 760 252,0 560 18C 520, 960, 33C 1360, 1000, 46C 880, 1600, 25C 200, 48U, 38C 1400, 720, 47C 1720, 2160, The data set forth in Table I is shown in graph form in Figure l, wherein resistance to penetration is plotted along the vertical axis and degree of tip bluntness, expressed as a percentage, is plotted along the horizontal axis. Proceeding from uppermost to lowest, the four curves in Figure 1 correspond to gloved plantar skin, gloved palmar skin, abdominal rectus muscle, and intercostal rnuscle, respectively. As can be seen with reference to Figure l, at all bluntness settings both gloved palmer skin and gloved plantar skin exhibit a greater resistance to penetration than do abdominal rectus fascia/muscle or intercostal fascia/muscle. Further, as can be seen with reference to Figure 2, the difference in penetration force between gloved skin (plantar) and fascia/muscle (abdominal rectus) remains about the same for needle bluntness in the range between about 0 and 25%. However, as the degree of needle bluntness approaches about 25%, the difference in penetration force between gloved skin (palmar) and fascia/muscle (abdominal rectus) begins to increase. This difference in penetration 2p force continues to increase throughout the remaining range of needle bluntness. It is also perceived from these tests that at bluntness settings greater than about 62% the resistance to penetration of the type needle becomes sufficiently great in abdominal rectus and intercostal fascia/muscle that usage would be disfavored.
In a second series of tests, needles having bluntness settings in arrange from 25% to 62% were tested in comparison with totally sharp needles having 0% bluntness. The specific bluntness settings tested were 0%, 25%, 37%, 50%, and 62%.
Thirty-two penetration measurements were taken at each bluntness setting, broken into four test series identified as A, B, C and D. Each test series was done on a single cadaver. For each test, a needle was passed through muscle fascia and the required penetration force was recorded.
Thus, this series of tests involved 1.60 needles. Table II

VVO 92!08412 PCT/US91/08054 ~ ~ ~~ ~

shows the raw data~obtained while Table presents III a stati stical summary the results of thesetests. gure 3 of Fi is a graph showing variation in averagepenetration force the as a function of e bluntness using a obtainedfrom needl dat Table ITI. In Table II "Avg" refers e average orce of T to th f penet ration expressedin grams of the y-two tests thirt condu cted at each tness setting, while"SD' refersto the blun stand ard deviation the test results.
of TABhF TI

Abdom Rectus Gloved Cadaver Bluntness ing Mu~cle/Fascia Sett Palmar kin Difference A 0% 80.0 340.0 260.0 B 0% 80.0 225.0 145.0 C 0% 145.0 285.0 140.0 17 0 % 65. 0 210. 0 145. 0 A 25% 345.0 835.0 490.0 B 25% 375.0 845.0 470.0 C 25% 860.0 1355.0 495.0 D 25% 350.0 775.0 425.0 A 37% 515.0 925.0 410.0 B 37% 400.0 1000.0 600.0 C 37% 1040.0 1660.0 620.0 .

D 37% 465.0 1080.0 615.0 A 50% 910.0 1480.0 570.0 B 50% 555.0 1370.0 815.0 ~

C 50% 1450.0 2400.0 950.0 D. 50% 665.0 1145.0 480.0 A 62% 595.0 1420.0 825.0 g 62% 695.0 1610.0 915.0 ' C 62% 1755.0 3495.0 1740.0 D 62% 775.0 1930.0 1155.0 WO 92/08412 PCT/US91/0805~t ~~~~.~~J

TABLE III
Bluntness Setting Muscl~g/Fascia G1 ve Skin Diffezence 0% Avg = 92.5 Avg = 265.0 Avg = 172.5 SD - 41.2 SD - 70.9 SD - 69.2 25% Avg = 482.5 Avg = 952.5 Avg = 470.0 SD = 298.6 SD = 350.8 SD - 274.1 37% Avg = 605.0 Avg = 1166. 3 Avg = 561.3 SD - 325.6 SD ~- 399.2 SD - 350.8 50 % Avg = 895 . 0 Avg = 1598. 8 Avg _- 703,. 8 SD = 492.7 SD - 605.7 SD -- 445.6 62% Avg = 955.0 Avg = 2113.8 Avg ~- 1158.8 SD - 538.5 SD - 969.4 SD - 619.6 It is perceived that the degree of safety provided to an operator by a particular needle configuration is directly related to the magnitude of difference in the penetration force needed to pierce the target body tissues and the gloved hand of the operator. As is indicated by the data in Table III, a totally sharp needle having 0% bluntness requires an average of. 172.5 grams greater penetration force to penetrate gloved skin as compared to muscle fascia. This "safetx factor" of 172.5. grams is of course insufficient in many instances in preventing accidental sticks of the g3.oved hand of the operator. The Table III results show tk~at needles having a bluntness in the 25-62% range exhibit a much greater magnitude of difference in the penetration force needed to pierce the target body tissues and tyre gloved hand of the operator than sharp needles ~i.e., needles having 0%
bluntness).
Table IV indicates the average percent improvement in the safety factor provided by 25-62% blunt needles over sharp (0%
blunt) needles, based on the Tables II and III data. The average percent improvement in the safety factor is defined by the following formula wherein Asf is the average percent improvement in the safety factor, Pb is the average gloved skin penetration force at bluntness setting b, and Po is the average gloved skin penetration force for a sharp (On blunt) needle:
Asf (Pb/Po) x 100 TABLE IV

BluntnQss Setting P Pb Improvement o 250 265.0 952.5 359.4%

370 265.0 1166.3 440.10 500 265.0 1598.8 603.30 1S 620 265.0 2113.8 797.6%

Table V shows the minimum percent improvemerst in safety, defined by the following formula:
Msf = (Pb*/Po) x 100 In the above formula, M~f is the minimum percent improvement in the safety factor. Pb* is the minimum gloved skin penetration force at bluntness setting b calculated by subtracting the standard deviation in penetration force at bluntness setting b from the average penetration force at bluntness setting b. Thus, 84% of the penetrations at bluntness setting b will be higher than Pb*. Po is the average gloved skin penetration force for a sharp (0% blunt) needle.

TABLE V
Bluntness Setting Pa Pb* I~rovement 25% 265.0 X01.7 227.1%
37% 265.0 767.1 289.5%
50% 265.0 993.1 374.8%
62% 265.0 1144.4 431.8%
A preferred en~odiment of the surgical suture needle of the present invention, incorporating the desired safety characteristics is generally indicated at 10 in Figures 4 and 5. The needle 10 has a shaft portion 11 having a uniform outer diameter, and a tip portion 12 integrally formed with shaft portion 11 and extending distally therefrom. Iru order to provide stability and control of the needle 10 during use, the shaft portion 11 may have a flat pressed circular cross section such as shown in Figure 6 or, alternatively, a modified square cross sectional shape such as shown in Figure 7. In the needle 10 of Figure 4 the shaft portion 11 is curved and possesses a constant radius of curvature. This configuration is, however, not critical to the present invention and shaft portion 11 may therefore assume any straight and/or curved configuration which is considered suitable for the particular purpose that is intended. Both the shaft portion 11 and tip portion 12 are rigidly formed of a suitable material for suture needle use inside the body, such as surgical grade steel. The needle t:ip portion 12 has an essentially circular cross sectional shape, as shown in Figure 8, and a tapered :body 14. Also as shown in Figure 8 the needle tip portion 12 is of solid cross section and has no fluid passage therethrough. They needle tip portion 12 -17a-terminates in a blunt head 16 which is configured to permit piercing of muscle and fascia, muscle alone, adipose, pericostal tissue and other non-cutaneous soft tissues of the body while preventing skin penetration of the gloved hand of an operator. A~~ can be best appreciated with reference to Figure 5, riead 16 preferably has a part spherical shape which WO 92!08412 PCT1US91f08054 sv ~, '~~ i~ -1$-encompasses vertex 17 of tip portion 12. ether curved shapes may also be employed as suitable configurations for head 16°
so long as there are no sharp edge surfaces.
It should be noted that the surgical needle of the present invention is specifically designed such that it is not suitable for suturing cutaneous tissues. Accordingly, based upon the test results obtained, it is considered important that blunt head 16 have a minimum diameter of curvature which is at least '2S% of the diameter of the needle shaft portion 11 and a maximum diameter of curvature which no greater than about 62% of the diameter of the needle shaft.
Within this range, it is perceived that needles having a bluntness which is toward the higher end of the range will be especially preferred as they offer a greater safety factor while still being acceptable for use. Further, the diameter o.f the needle shaft should be in a range of about .026" to .05O" with the diameter of curvature of the needle tip ranging between about .006°' to about .031". In addition, it is considered critical that the entire needle tip portion has a continuously smooth outer surface lacking, any discontinuities or sharp cutting edges.
In practice, the surgical suture needle of the present invention may be used to.close non-cutaneous soft tissues of the body employing the same techniques used with conventional suture needles. However, since the cutaneous tissues of the wound cannot be closed with the !blunt tip needle, another closing technique must be used to complete the wound closure. This does not pose a problemr however, in that it is quite common to employ different closing techniques for closing the cutaneous and non-cutaneous tissues in a wound.
For example, the needle of the present invention may be used to close the non-cutaneous tissues while final closure of the cutaneous tissues may be accomplished by conventional stapling techniques.
It is perceived that the blunt needle of the present VVO 92/0412 pCT/US91/0~054 -19- 2~~~~1~
invention may, in addition to reducing the risk of infectious disease transmission by reducing the risk of an accidental needle stick, also serve to reduce the risk of needle contamination by reducing the amount of bleeding caused by the needle. Decreased bleeding occurs because the blunt needle is more likely to simply push blood vessels aside rather than penetrate them as it is being advanced in the body.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.

Claims (4)

CLAIMS:

1. A surgical needle for use in suturing non-cutaneous soft tissues of the body, comprising:
a needle shaft; and a needle tip, said needle shaft and needle tip intergrally formed of a rigid material suitable for use inside the body and containing no fluid passages therethrough, said needle tip having a body portion integrally formed with and extending from said needle shaft, said body portion being tapered along the length thereof, said needle tip further having a blunt head adapted to penetrate muscle and fascia, muscle alone, adipose, pericostal tissue and other non-cutaneous soft tissues of the body while preventing skin penetration of the gloved hand of an operator.

2. The surgical needle of claim 1 wherein said needle tip has a continuously smooth outer surface lacking any sharp cutting edges and said blunt head has a part spherical shape and a vertex which forms a portion of said part spherical shape.

3. The surgical needle of claim 2 wherein said blunt head has a diameter of curvature which is in the range of 25% to 62% of the diameter of said needle shaft and said diameter of curvature is at least about .006".

4. The surgical needle of claim 1 wherein the diameter of said needle shaft is in a range of about 0.026"
to .050" and the diameter of curvature of said needle tip is no greater than about .031".