Spinal needle abstract
A double-hole pencil-point (DHPP) spinal needle is composed of
a closed end blunt ogival or pencil point tip and two circular coaxial
holes in close proximity to the tip. Anesthetic solution may be
injected through the coaxial holes in a direction parallel to the
long axis of the spinal fluid column which allows an even anesthetic
distribution with a low dosage required. The spinal needle of the
present invention allows anesthetic solution to be injected even
when one of the holes is obstructed by a tissue fragment and rapid
reflux of cerebral spinal fluid at twice the rate of single hole
pencil point spinal needles.
Spinal needle claims
What is claimed is:
1. A needle for penetrating a spinal fluid column and dispensing
anesthesia consisting of:
a substantially conical or ogival pencil point tip including a
perforating end;
a hollow substantially cylindrical shaft, and a pair of coaxially
positioned apertures disposed at a junction of said shaft and tip,
and said tip and shaft being coupled through said apertures, said
needle further comprising a length sufficient to linearly penetrate
dura matter and enter a subarachnoid space, so that said tip and
said two coaxially disposed apertures are concurrently positionable
within the subarachnoid space.
2. A needle for penetrating a spinal fluid column and dispensing
anesthesia consisting of
substantially conical or ogival tip including a perforating end;
and
a hollow substantially cylindrical shaft, said shaft including
a pair of coaxially positioned apertures, disposed at a junction
of said shaft and tip and said tip and shaft being coupled through
said apertures.
3. The needle according to claim 2 said needle comprising a length
sufficient to linearly penetrate dura matter and enter a subarachnoid
space, so that said tip and said two coaxially disposed apertures
are concurrently positionable within the subarachnoid space.
4. The needle according to claim 3 wherein a diameter of said
apertures is between approximately 0.008 and 0.0135 inches.
5. The needle according to claim 3 wherein said apertures are
positioned such that a distance between said perforating end and
a leading edge of said apertures is between approximately 0.025
and 0.055 inches.
6. The needle according to claim 2 wherein an outside diameter
of said needle is between approximately 0.0180 and 0.0185 inches.
7. The needle according to claim 5 wherein an inside diameter
of said needle is between approximately 0.0115 and 0.0130 inches.
8. The needle according to claim 2 wherein said apertures are
substantially the same diameter.
9. The needle according to claim 2 said needle further comprising
an obturator for covering and blocking said apertures during insertion
of said needle into tissue.
10. The needle according to claim 2 further comprising an anesthetic
solution for injecting through said needle to flow outwardly through
said apertures.
11. The needle according to claim 3 further comprising an anesthetic
solution for injecting into the subarachnoid space.
12. The needle according to claim 11 said anesthetic solution
injected through said apertures.
13. The needle according to claim 12 wherein said apertures are
substantially equal in diameter.
14. The needle according to claim 3 wherein said apertures are
substantially equal in diameter.
15. A needle for penetrating a spinal fluid column and dispensing
anesthesia consisting of:
a substantially conical or ogival pencil point tip including a
perforating end;
a hollow substantially cylindrical shaft, and a pair of coaxially
positioned apertures disposed at a junction of said shaft and tip,
and said tip and shaft being coupled through said apertures.
16. The needle according to claim 15 wherein a diameter of said
apertures is between approximately 0.008 and 0.0135 inches.
17. The needle according to claim 15 wherein said apertures are
positioned such that a distance between said perforating end and
a leading edge of said apertures is between approximately 0.025
and 0.055 inches.
18. The needle according to claim 15 wherein an outside diameter
of said needle is between approximately 0.0180 and 0.0185 inches.
19. The needle according to claim 15 wherein an inside diameter
of said needle is between approximately 0.0115 and 0.0130 inches.
20. A needle for penetrating a spinal fluid column and dispensing
anesthesia consisting of:
a substantially conical or ogival pencil point tip including a
perforating point generally expanding out to a distal end;
a hollow substantially cylindrical shaft portion; and
a pair of coaxially positioned apertures disposed at a junction
of said shaft and tip, extending through said shaft portion directly
adjacent to said distal end of said pencil point tip.
21. The needle according to claim 20 wherein said pencil point
tip is conical.
22. The needle according to claim 20 wherein said pencil point
tip is ogival.
Spinal needle description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for spinal anesthesia.
In particular, the present invention relates to a double-hole pencil-point
(DHPP) spinal needle.
2. Discussion of the Background Information
In 1926 a needle with a round, tapering, and sharp point was described
by Greene in, "Lumbar Puncture and the Prevention of Post-Puncture
Headache", JAMA, vol. 86 pp. 391-92 (1926). This article was
the result of experiments made during 1923 and of experience and
observation following those experiments. The article concluded that
"postpuncture headache is caused by trauma to the spinal dura
sufficient to result in excessive leakage of cerebrospinal fluid
to the point at which the brain is left without a water cushion".
These experiments demonstrated that a greater trauma was produced
by the use of a needle with a blunt cutting point than by a needle
of the same caliber with a rounded, tapered and sharpened point.
It was also found possible to pass a small sharp, round, tapering
pointed instrument between the fibers of a spinal dural sac, suspended
and filled with water, without cutting any of them. He performed
215 consecutive punctures with this needle, with a headache incidence
of only two in the series.
In 1931 Kirschner, in "Versuche Zur Herstellung Einer Gurtelformigen
Spinal Anaesthesia", Arch. Klin. Chir., vol. 167 pp. 755-60
(1931) described a needle for spinal anesthesia. The needle described
by Kirschner was formed with an opening in the shaft proximal to
the beveled closed end. This needle was recommended to give more
accurate control to the duration and extent of anesthesia because
the needle could be manipulated to permit injection of solution
in a direction parallel to the long axis of the spinal fluid column
rather than against the side of the canal opposite puncture.
Hart and Whitacre (4) described a pencil-point spinal needle in
"Pencil-Point Needle in Prevention of Postspinal Headache",
JAMA, vol. 147 pp. 657-658 (1951). The pencil point spinal needle,
known as the Whitacre needle, is shown in FIG. 2.
The Whitacre needle was modified by Sprotte et al., "Eine
Atraumatishe Universalkanule fur Einzeitige Regionalanaesthesien",
Reg. Anaesthe., vol. 10 pp. 104-8 (1987). The needle has since
been known as the Sprotte needle, shown in FIG. 1. In the years
since the Sprotte needle was described, there has been a resurgence
of spinal anesthesia in many operating rooms around the world. This
resurgence has been fueled by a breakthrough in regional anesthesia
called combined spinal-epidural anesthesia. The pencil-point spinal
needle is an exceptional device for delivering the anesthesia. Consequently,
the FDA only approves of using pencil-point spinal needle in the
needle-through-needle or Eldor needle techniques for combined spinal-epidural
anesthesia.
However, the long orifice 101 of a 24 gauge Sprotte spinal needle
may result in failed spinal anesthetics because the length of the
orifice 101 exceeds the 1 mm thickness of human lumbar dura. Accordingly,
Sprotte modified his spinal needle by reducing the length of the
orifice. However, Sosis et al., in "An In-Vitro Evaluation
of the New Shorter Orifice Sprotte Spinal Needle", Anesth.
Analg., vol. 78 pg. S410 (1994) compared in-vitro the 1.8 mm long
lateral orifice of the original version of the Sprotte spinal needle
with the 1.0 mm long orifice of the modified Sprotte needle. Sosis
et al. found that the flow of water through the needle was not reduced
even after the orifice length was reduced by 44%.
Lipov et al. examined whether the window design of Sprotte pencil-point
needles leads to deformation under lateral or axial loading conditions.
"Does the Design of the Sprotte Spinal Needle Reduce the Force
Needed to Deform the Tip?", J. Clin. Anesth., vol. 6 pp.411-13
(1994) examined the 22- and 24-gauge Sprotte needles, 22- and 25-gauge
Whitacre needles, and 22- and 25-gauge Quincke needles. The lateral
or axial force required to bend a Sprotte needle was less than necessary
for either of the Whitacre or Quincke needles of similar size. It
was also noted that the tips of the Sprotte needles were most likely
to bend at the needle window, while the Quincke and Whitacre needles
deformed at the clamping point. Lipov et al. concluded that Sprotte
needles have an inherent design weakness to lateral and axial pressure,
which may result in a greater number of needle tip deformations
upon insertion. As a result of this deformation, difficulty in needle
withdrawal and possibility of needle tip fracture may occur.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a spinal needle
that avoids the risk of needle deformation due to bending at the
window, as with Sprotte needles. It is another object of the present
invention to provide a spinal needle which doubles rapid cerebral
spinal fluid (CSF) reflux.
According to one aspect of the present invention, a new pencil-point
spinal needle is described that avoids the drawbacks of conventional
Sprotte and Whitacre needles.
Accordingly, a double-hole pencil-point (DHPP) spinal needle is
composed of a closed end blunt ogival, or pencil-point, tip and
two circular holes opposing each other in close proximity to the
tip. The area of each of the two holes is approximately one-half
the area of a single Sprotte hole.
According to another aspect of the present invention, the anesthetic
solution injected through the coaxial holes allows more even anesthetic
distribution and less anesthetic solution dosage.
According to yet another aspect of the present invention, the DHPP
spinal needle allows anesthetic solution to be injected even when
one of the holes is obstructed by a tissue fragment.
Accordingly, the present invention provides a device for spinal
anesthesia that includes a pencil point needle. The needle includes
two coaxially disposed round holes proximal to a tip.
According to another aspect of the present invention, the two coaxially
disposed round holes have the same diameter.
According to a further aspect of the present invention, an obturator,
insertable within the needle, is provided for closing the coaxially
disposed holes from the inside of the needle.
According to yet another aspect of the invention, the needle includes
a length sufficient to linearly penetrate dura matter and enter
a subarachnoid space, so that the tip and the two coaxially disposed
round holes are concurrently positionable within the subarachnoid
space.
According to another aspect of the present invention, the device
include cerebral spinal fluid refluxing through the two coaxial
holes.
According to another aspect of the invention, an anesthetic solution
is included for injecting through the needle to flow outwardly through
the two coaxially disposed round holes into a subarachnoid space.
Accordingly, the present invention also provides a needle for penetrating
a spinal fluid column and dispensing anesthesia that includes an
ogival tip with a perforating end and a hollow shaft. The shaft
includes a pair of coaxially positioned apertures and the tip and
shaft are coupled through the apertures.
According to another aspect of the present invention, a diameter
of the apertures is between approximately 0.008 and 0.0135 inches.
According to yet another aspect of the present invention, the apertures
are positioned such that a distance between the perforating end
and a leading edge of the apertures is between approximately 0.025
and 0.055 inches.
According to a further aspect of the invention, an outside diameter
of the needle is between approximately 0.0180 and 0.0185 inches.
According to another aspect of the invention, an inside diameter
of the needle is between approximately 0.0115 and 0.0130 inches.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is further described in the detailed description
which follows, by reference to the noted plurality of drawings by
way of non-limiting examples of preferred embodiments of the present
invention, in which like reference numerals represent similar parts
throughout the several views of the drawings, and wherein:
FIG. 1 shows a prior art Sprotte needle device;
FIG. 2 shows a prior art Whitacre needle;
FIG. 3 shows a top view of the device according to the invention;
FIG. 4 shows a lateral view of the device according to the present
invention; and
FIG. 5 shows a sectional view of the device according to the present
invention and an obturator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The particulars shown are by way of example and for purposes of
illustrative discussion of the preferred embodiments of the present
invention only and are presented in the cause of providing what
is believed to be the most useful and readily understood description
of the principles and conceptual aspects of the invention. In this
regard, no attempt is made to show structural details of the invention
in more detail than is necessary for a fundamental understanding
of the invention, the description taken with the drawings making
apparent to those skilled in the art how the several forms of the
invention may be embodied in practice.
FIGS. 3 and 4 show an insertion end of a double-hole pencil-point
(DHPP) needle 10 of the present invention. The pencil point needle
includes a blunt tip 20 for performing, e.g., a lumbar puncture.
The needle 10 also includes two coaxially disposed holes 11a, 11b
preferably of even diameter and positioned in proximity to the tip
20. Holes 11a, 11b are positioned such that anesthetic solution
flowing through needle 10 is forced through the holes 11a, 11b and
in opposite directions.
According to the present invention, the diameter of coaxial holes
11a, 11b within the spinal needle 10 may be between, for example,
approximately 0.008 and 0.0135 in. The distance from tip 20 to hole
11a (or 11b) is intended to remain small so that the tip and coaxial
holes may be positionable within the subarachnoid space together.
Thus, the preferred distance between the tip 20 and a leading edge
of hole 11a (or 11b) is between, for example, approximately 0.025
and 0.055 in. The outside diameter of the spinal needle 10 may be
between, e.g., 0.0180 and 0.0185 in. while the inside diameter may
be between, e.g., 0.0115 and 0.0130 in. While the overall length
of the spinal needle may vary according to the user's needs, the
length must be sufficient to enable the tip and holes to penetrate
the dura matter and enter the subarachnoid space.
In use, the needle is generally positioned such that the holes
11a, 11b are to be coaxially aligned with the long axis of the spinal
fluid column and designed for linear penetration of the dura matter
and for entering the subarachnoid space. As shown in FIG. 5 an
obturator 30 or mandrel, which may be made of conventional design
and materials as known to those ordinarily skilled in the art, may
be inserted within the spinal needle to cover and block holes 11a,
11b from the inside during insertion, as shown in the phantom lines.
The obturator 30 positioned as shown in the phantom lines, enables
the spinal needle to penetrate tissue without any tissue fragments
entering the internal portion of the needle. Once the needle is
properly inserted, the obturator 30 is completely removed from the
needle in a left direction along arrow 31 to enable the injection
of anesthesia.
The preferred embodiment of the present invention allows anesthetic
to flow into the spinal fluid column through, e.g., hole 11b, even
when one of the holes, e.g., 11a, is blocked or obstructed by, e.g.,
a tissue fragment. Further, the dual directed, i.e., unobstructed,
injection of anesthetic solution into the spinal fluid column enhances
the diffuse distribution while reducing the required dosage amount.
The pencil-point needle, according to the present invention, may
be made of metal or similar composition, as known by those ordinarily
skilled in the art. Further, the pencil-point needle may also be
used in the same manner as the conventional pencil point needles
described above, without suffering the noted drawbacks. The reduced
hole size of the present invention avoids the risk of deformation
so common in Sprotte needles. Whereas, the double hole design enables
the rapid CSF reflux on the order of twice that of the single hole
Whitacre needle.
It is noted that the foregoing examples have been provided merely
for the purpose of explanation and are in no way to be construed
as limiting of the present invention. While the invention has been
described with reference to a preferred embodiment, it is understood
that the words which have been used herein are words of description
and illustration, rather than words of limitation. Changes may be
made, within the purview of the appended claims, as presently stated
and as amended, without departing from the scope and spirit of the
invention in its aspects. Although the invention has been described
herein with reference to particular means, materials and embodiments,
the invention is not intended to be limited to the particulars disclosed
herein; rather, the invention extends to all functionally equivalent
structures, methods and uses, such as are within the scope of the
appended claims. |