Surgical needle abstract
A curved surgical needle which may be helical or planar and in
which the curvature may be constant or varied with the pointed end
offset from the principal longitudinal axis.
Surgical needle claims
I claim:
1. A surgical needle comprising a curved body portion terminating
in one direction in a blunt end and in the other direction in a
pointed end section, said pointed end section being laterally offset
from said curved body portion, said curved body portion and said
pointed end section together forming substantially no more than
180 degrees of arc and said pointed end section is offset 5 degrees
to 60 degrees.
2. A needle according to claim 1 wherein the axis of curvature
of one curved body portion is offset from the axis of curvature
of another body portion 5 degrees to 60 degrees.
3. A needle in accordance with claim 1 wherein a portion of said
curved body portion forms a portion of a helix formed by said portion
with another body portion of said needle.
4. A needle in accordance with any of claims 1 or 3 in which a
portion has a flattened surface formed on the side facing the axis
of curvature of said portion.
5. A surgical needle in accordance with any of claims 1 or 3 in
which said offset is 15 degrees to 30 degrees.
6. A surgical needle in accordance with any of claims 1 or 3 in
which the radius of curvature of each portion is constant.
7. A surgical needle in accordance with any of claims 1 or 3 in
which the radius of curvature of at least two portions differ the
one from the other.
8. A surgical needle in accordance with any of claims 1 or 3 in
which the radius of curvature of a portion proximal to the said
pointed end is shorter than the radius of curvature of a portion
more distal to said pointed end.
9. A needle according to claim 2 wherein said pointed end is offset
a distance in the range of 0.010" to 0.040" at its termination.
10. A needle in accordance with claim 9 in which the length of
the pointed end section is offset about 5% to 20% of the curved
length of the curved body portion of said needle.
Surgical needle description
BACKGROUND OF THE INVENTION
The present invention relates to surgical needles and more particularly
to specially curved surgical needles especially advantageous for
use in opthalmic microsurgery, and other microsurgery and the like.
Surgical needles can be any of a variety of shapes ranging from
straight, to ski-shaped to curved. Curved needles are essential
to most surgical procedures involving delicate or fine tissue to
accurately locate the suture loop with a minimum of trauma to the
tissue. To insert a curved needle, the surgeon must grasp the shaft
of the needle with a needle holder at a point generally near the
center of the needle or toward its butt to engage the tip in the
tissue near the edge of the incision or wound. Then the suture is
passed through the tissue and turned to pass through the tissue
on the opposite side of the incision or would by a semi-rotational
movement of the surgeon's fingers, wrist and forearm. The curvature
of the needle helps establish for the surgeon the desired "bite
" while the arcs of rotation of the surgeon's wrist and forearm
or, more precisely, the arc of rotation of the needle holder held
by the surgeon, establish the angulation (non-radiality) or non-angulation
(radiality) of the suture across the incision or wound.
It is extremely important in certain microscopic surgery involving
fragile tissue, such as in eye surgery or in anastomosis or other
connection of fragile vessels or tubes, that the geometry of the
path of the needle placing an appositional suture be uniform so
as not to exert unequal or contrary forces parallel or tangential
to the edge of the incision or would when the suture loop is formed
and tied. This is important not only with individual (non-continuous)
suturing but also when suturing using multiple continuous bites.
For example, in a corneal transplant a continuous suture is made
to define a series of isosceles triangles, so as not to induce undesirable
rotative force between graft and recipient cornea.
Curved surgical needles, according to prior art construction, are
curved in a single plane. As a surgeon observes them, particularly
when through a vertically directed surgical microscope, and seeks
to establish and maintain a precise arc of rotation for needle placement,
he or she must be able to observe the location of the needle and
when possible its point at all times during passage. To do this
requires either that the head or visual axis be moved somewhat to
one the side, impossible under a powerful microscope, or, alternatively,
to tilt the plane of curvature of the needle, thereby altering the
direction of penetration of the needle in the tissue.
PRIOR ART
The prior art shows various curved needles of the type to which
the subject invention can be applied, such as U.S. Pat. No. 3394704
Dery showing a needle curved in a single plane, and to the same
effect to Kurtz U.S. Pat. Nos. 2869550 and 3094123 as well
as the application of myself and Walter McGregor, Ser. No. 437419
now U.S. Pat. No. 4524771 incorporated herein by reference and
the art cited therein.
A helical needle whose helix passes through more than 360 degrees
is shown in the 1972 edition of Zentralblatt fur Chirurgie in Vol.
15 starting at page 480. The purpose here is to enable rapid closure
of a large wound. The helical needle is never disengaged from the
tissue being sutured and hence a surgeon there does not have to
continuously grasp a suturing needle. The helical needle of said
Zentralblatt curves through more than 360 degrees of helix.
SUMMARY OF THE PRESENT INVENTION
The needle in accordance with the present invention is formed so
that while its curvature has one or more radii, the curve is not
in one plane but, to the contrary, is at an angle to any plane positioned
at right angles to an axis of curvature or, alternatively, the pointed
tip is offset so that the tip is visible to a surgeon viewing the
needle from above as through a surgical microscope. Additionally,
any flat portion of the needle on the inside of the curve, which
aids the surgeon to grasp the needle more firmly than a rounded
surface, is rotated or torqued as the needle curves so that its
surface always faces and is parallel to the axis of curvature. This
improvement may be applied to needles of constant curvature as well
as to the compound curved needle shown and claimed in my patent
with Walter McGregor, supra. The angle between a body portion of
the needle and a plane normal to an axis of rotation may be useful
from 5 degrees to 60 degrees. In a preferred embodiment, particularly
useful in opthalmic surgery, I have found angles of 15 degrees to
30 degrees most useful.
In use, a surgeon grasps the needle with the needle holder at the
appropriate shaft position for that needle curvature and inserts
the point into the tissue to begin the 37 bite" into the tissue
on, for example, the distal side of the incision. He or she begins
penetration driving the needle tip downward through the tissue while
in microsurgery looking down through the microscope. The view of
the needle tip and transparent corneal tissue is not blocked by
the shaft of the needle or by the needle holder enabling the surgeon
to precisely guide the point visually through the entire bite. As
the needle is rotated to engage the opposite side of the incision,
the axis of rotation of the needle holder remains parallel to the
axis of curvature of the needle. The linear offset of the tip of
the needle from the body of the needle permits a continuous view
of the needle tip without the necessity of lateral displacement
of the surgeon's head (impossible in microsurgery).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is a preferred embodiment showing a compound curved needle
formed as part of a helix illustrating the offset tip in accordance
with the invention;
FIG. 1b is a side view of FIG. 1a.
FIG. 2 is a cross-sectional view taken on line 2--2 of FIG. 1b;
FIG. 3 is a cross-sectional view taken on line 3--3 of FIG. 1b;
FIG. 4 is a cross-sectional view taken on line 4--4 of FIG. 1b;
FIG. 5 is an embodiment showing a constant curved needle in one
plane with the alternative offset tip end;
FIG. 5b is a side view of FIG. 5a;
FIG. 6a shows a perpendicular or radially placed stitch closing
a linear incision. This is to be avoided in light or fragile tissue
since such a stitch induces displacement of opposing wound edges.
FIG. 6b shows the preferred "isosceles" stitch (limited
movement of force) which avoids linear displacement of opposing
wound margins;
FIG. 7a illustrates an undesirable continuous stitch in a circular
corneal transplant comparable to the stitch in FIG. 6a and
FIG. 7b illustrates the preferred continuous "isosceles"
in a circular corneal transplant comparable to the stitch in FIG.
6b.
FIG. 8 is a front elevation of a needle formed as part of a helix
showing an offset tip.
DETAILED DESCRIPTION
Referring to the drawings, FIGS. 1a and 1b show a preferred compound
curved surgical needle 20 in accordance with my invention to which
is secured the suture 22. The needle has a straight pointed end
section 24 adjacent a curved body portion 26 with subsequent body
portions 28 of reducing curvature (increasing radius of curvature).
The cross-sectional shape at sections 24 26 and 28 are shown in
FIGS. 2 3 and 4 respectively. As can be seen from FIG. 1a, the
point 24 is offset from the body portion 28 and to a progressively
lesser extent from body portion 26. The helical angle between the
axis of the helix (axis of curvature of the helix); and a body portion
is preferably 15 degrees to 30 degrees but may in some instances
be as little as 5 degrees and as great as 60 degrees. In a needle
in which the pointed end section 24 triangular in cross-section
(FIG. 3) is 0.05" the offset would be nominally 0.025"
with a range of 0.010" to 0.040" . The needle may be provided
with a flattened surface or face 36 which in any portion faces the
axis of concavity of the curvature.
As illustrated, the needle 20 has an offset tip 24 and a body portion
of successively increasing radii of curvature proceeding from tip
24 through portions 26 and 28 as more fully described in the above-mentioned
Troutman et al patent incorporated herein by reference. As illustrated
in FIG. 1b, the axis of curvature of each helical body portion 2628
is co-axial although the radius of curvature is different. It should
be noted that in the subject invention the offset may begin at any
point along the body portions.
FIG. 5a illustrates an embodiment of my invention which incorporates
the features in a needle of constant curvature. A needle of the
same length but of compound curvature requires less offset than
a needle of constant curvature because the chord 25a is longer than
chord 25b and the grasping point of the compound curved needle is
more distal from the needle point. The grasping point is normally
located from the tip two-thirds the distance from tip to butt as
opposed to the center as in a needle of constant curvature. Needle
21 has a tip section 40 offset from the longitudinal axis of the
needle. The sections 42 44 and 46 as illustrated are of constant
radii. These sections, however, may optionally be offset in the
manner illustrated for the tip 40 so that the offset is obtained
by a more gradual but irregular helix.
These needles may be manufactured by any of the methods well known
in the art of needle manufacture. In general, the form of the needle
may be best understood by bending the wire from which the needle
is formed around a mandrel whose surface contains the desired curves.
For example, to make the needle 21 illustrated in FIGS. 5 and 5b
a mandrel of constant diameter would be employed and the needle
would be offset by being placed in a spiral curve which is cut in
the mandrel and has a cross-sectional area and shape corresponding
to that of the needle. The spiral would form with a plane normal
to the axis of the mandrel an angle corresponding to the desired
angle. In the case of the needle of FIGS. 1a, 1b, a tapered mandrel
would be employed with a spiral curved as described above.
The taper would supply the decreasing radii for the several sections
of needle 20. It is important that the gentler curve be placed in
the wire first and then more tightly curved in the continuous operation.
As clearly shown in the drawings, needles in accordance with my
invention do not exceed 360 degrees and preferably are less than
180 degrees arc curvature.
FIGS. 6a and 7a illustrate radially placed continuous suturing
stitches, generally not desirable for lighter or fragile tissue.
The length of the external suture limb EL has a greater angle with
respect to the incision 5060 than does the internal (in the tissue)
suture limb HL. This causes a larger force vector 52 of the externalized
limb of stitch EL parallel to the incision 5060 than does the force
vector 54 of the perpendicular internal stitch HL. Consequently,
the tissues to each side of the incision 5060 are drawn in contrary
and unequal sliding motions as illustrated by the two unequal force
vectors 52 and 54 exerted by the external limb EL and the internal
limb HL, respectively. This not only delays healing but also can
cause a displacement at the locations 56 and 58. In the case of
eye surgery this induces optical distortions of the cornea.
A stitch illustrated in FIGS. 6b and 7b in which the internal stitch
HL and the external stitch EL are of equal length, form the same
angle with the incision 50a, 60a and cancel out the sliding motion
caused by vectors of unequal magnitude. It will be noticed that
the lines of the continuous stitch form a series of isosceles triangles
and that is what is meant in this patent application when the term
isosceles stitch is employed. Individual radially placed or perpendicularly
placed interrupted sutures such as illustrated on Plate 6-13 at
p. 188 of Microsurgery of the Anterior Segment of the Eye, Vol.
1 pp. 188 through 195 can be used alternatively and their placement
is similarly advantaged.
It should be obvious to one skilled in the art that in all instances
direct visualization of the offset needle point during needle passage
facilitates the accurate placement of both individual and continuous
sutures essential to anatomical (and, in the case of eye surgery,
optical) precise would apposition.
I have illustrated in FIGS. 1a and 1b a compound curved surgical
needle formed as a helix in accordance with this invention. The
needle of constant curvature shown in FIGS. 5a and 5b could, of
course, be made helical as in the needle illustrated in FIGS. 1a
and 1b. In fact, the compound curvatured needle formed as a helix
to obtain the offset is my preferred embodiment. However, I have
shown the needle 21 in a non-helical form to illustrate that the
offset may be obtained by offsetting the point. It should be understood
that an irregular helix is also within the purview of my invention.
Thus, FIGS. 5a and 5b illustrate other embodiments of my invention
with my preferred embodiment illustrated in FIGS. 1a, 1b.
If desired, the tip of FIG. 5a could be used with the helix of
FIG. 1a as shown in FIG. 8. Also both the compound curve and constant
curve can selectively be formed on a helix or in one plane to an
offset tip. My preferred embodiment for the more rigid tissue encountered
in corneal surgery is the compound curve needle formed on a helix
to provide the offset tip.
|