U.S. patent application number 10/201112 was filed with the patent office on 2003-02-13 for hollow curved superelastic medical needle and method.
Invention is credited to McGuckin, James F. JR..
Application Number | 20030032929 10/201112 |
Document ID | / |
Family ID | 26809076 |
Filed Date | 2003-02-13 |
United States Patent
Application |
20030032929 |
Kind Code |
A1 |
McGuckin, James F. JR. |
February 13, 2003 |
Hollow curved superelastic medical needle and method
Abstract
A needle assembly 10 compromising an infusion needle 11 that
includes a needle cannula 13 made of a superelastic material such
as Nitinol. The needle cannula is cold-worked or heat annealed to
produce a preformed bend 16 that can be straightened within
passageway 21 of a coaxial outer cannula 12 for introduction into
the body of a patient. Upon deployment from the outer cannula, the
needle cannula substantially returns to the preformed configuration
for the introduction or extraction of materials at areas lateral to
the entry path of the needle assembly. The needle assembly can
compromise a plurality of needle cannulae than can be variably
arranged or configured for attaining a desired infusion
pattern.
Inventors: |
McGuckin, James F. JR.;
(Radnor, PA) |
Correspondence
Address: |
Rex Medical, L.P.
585 County Line Road
Radnor
PA
19087
US
|
Family ID: |
26809076 |
Appl. No.: |
10/201112 |
Filed: |
July 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10201112 |
Jul 22, 2002 |
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09668067 |
Sep 22, 2000 |
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6425887 |
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09668067 |
Sep 22, 2000 |
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09457844 |
Dec 9, 1999 |
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60111624 |
Dec 9, 1998 |
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60130597 |
Apr 22, 1999 |
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Current U.S.
Class: |
604/272 |
Current CPC
Class: |
A61B 17/3478 20130101;
A61M 25/06 20130101; A61B 17/1671 20130101; A61B 17/3468 20130101;
A61M 25/0043 20130101; A61B 17/3417 20130101; A61M 2025/0007
20130101; A61B 2017/00867 20130101; A61M 2205/0266 20130101; A61M
25/0606 20130101; A61M 25/0041 20130101; A61B 2017/00261
20130101 |
Class at
Publication: |
604/272 |
International
Class: |
A61M 005/32 |
Claims
What is claimed is:
1. A needle assembly comprising an infusion needle having a
passsageway and at least one needle cannula having a distal tip, at
least one of said cannula, while in an unconstrained configuration
having at least one preformed bend and being constrainable to a
second configuration whereby upon release of external constraint,
said cannula substantially returns to the unconstrained
configuration.
2. The needle assembly of claim 1, wherein the constrained
configuration is substantially straight.
3. The needle assembly of claim 1, further comprising a coaxial
outer cannula for constraining the cannula with preformed bends
into the second configuration.
4. The needle assembly of claim 1 wherein the preformed bend
cannula comprises a superelastic material.
5. The needle assembly of claim 4 wherein the superelastic material
includes a Ni--Ti alloy.
6. The needle assembly of claim 4 whereby the preformed bend is
induced by mechanical deformation such that the superelastic
material includes a martensitic crystalline structure, while
non-mechanically deformed portions of the needle cannula comprise a
substantially austenitic crystalline structure.
7. The needle assembly of claim 1 further comprising an inner
needle introducer stylet having a stylet shaft which is insertable
into the passageway of the infusion needle.
8. The needle assembly of claim 1 wherein the stylet shaft
comprises a flexible polymeric material.
9. The needle assembly of claim 1 wherein the infusion needle
includes a needle cannulae.
10. The needle assembly of claim 9 wherein the plurality of needle
cannulae radiate outward from a proximal cannula forming a multiple
needle assembly.
11. The needle assembly of claim 9 wherein the multiple needle
assembly includes both at least one proximally-located needle and
at least one distally-located needle.
12. The needle assembly of claim 11 further including a coaxial
outer cannula for constraining the preformed and bent one needle
cannula into the second configuration, the outer cannula having at
least one side hole for deployment of at least one of the
proximally located needles therethrough.
13. The needle assembly of claim 11 further comprising an
introducer cannula for selectively exposing side holes for
deployment of a proximally located needle.
14. The needle assembly of claim 1 wherein the infusion needle
further comprises a plane indicator for indicating the direction of
a preformed bend of the needle cannula.
15. A needle assembly comprising: (a) an infusion needle comprising
at least one needle cannula made of a superelastic material, having
at least one preformed bend while in its unconstrained
configuration; and (b) a coaxial outer cannula having a distal end
and passageway therethrough, the infusion needle being adapted to
be disposed inside the passageway of the coaxial outer cannula to
constrain the infusion needle into the second configuration; (c)
the infusion needle being slidably deployable from the distal end
of coaxial outer cannula whereby at release of constraining forces,
the at least one needle cannula substantially returns to the
unconstrained configuration.
16. The needle assembly of claim 15 wherein the distal end of the
coaxial outer cannula includes a sharpened tip adapted for the
penetration of tissue.
17. The needle assembly of claim 15 wherein the coaxial outer
cannula further includes an outer cannula introducer stylet
insertable into the passageway of the coaxial outer needle such
that the coaxial outer needle and an outer cannula introducer
stylet comprise an outer needle assembly adapted for insertion into
the body of a patient.
18. The needle assembly of claim 15 wherein the superelastic
material includes a Ni--Ti alloy.
19. The needle assembly of claim 4 whereby the preformed bend is
induced by mechanical deformation of the needle cannula such that
the superelastic material of the at least one preformed bend
includes a martensitic crystalline structure, while
non-mechanically deformed portions of the needle cannula comprise a
substantially austenitic crystalline structure.
20. The needle assembly of claim 14 wherein the infusion needle and
coaxial outer cannula are interconnected by a coaxial handle.
21. A needle assembly comprising: an infusion needle having a
plurality of needle cannulae each having a distal tip, the
plurality of needle cannulae while in their unconstrained
configuration having a preformed bend with an angle within a range
from 40 to 90.degree., the preformed bends being
mechanically-induced martensite with straight portions of said
inner hollow cannula comprised of austenitic state Ni--Ti alloy,
the plurality of needle cannulae constrainable to a second
configuration that is substantially straight, whereby upon release
of external constraining forces, the plurality of needle cannulae
substantially return to their unconstrained configuration, the
infusion needle comprising a Ni--Ti alloy, the preformed bends of
the plurality of needle cannulae induced by mechanically deforming
the needle cannula, each preformed bend includes a martensitic
crystalline structure, while non-mechanically deformed portions of
the needle cannulae comprise a substantially austenitic crystalline
structure; a coaxial outer cannula having a distal end and
passageway therethrough, the infusion needle adapted to be disposed
thereinside the passageway of the coaxial outer cannula to
constrain the infusion needle into the second configuration; the
infusion needle being slidably deployable from the distal end of
coaxial outer cannula whereby at release of constraining forces the
plurality of needle cannulae substantially return to their
unconstrained configuration; an inner needle introducer stylet
having a stylet shaft, the stylet shaft being insertable into the
passageway of the infusion needle; and an outer cannula introducer
stylet that is insertable into the passageway of the coaxial outer
needle such that the coaxial outer needle and outer cannula
introducer stylet comprise an outer needle assembly adapted for
insertion into the body of a patient.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is filed under 35 U.S.C. 120 as a division
of a patent application filed Dec. 9, 1999 in the name of Dr. James
F. McGuckin, Jr. in whose name this application is submitted, and
in the names of Avery J. Evans, Beth A. Kirts, Edward J. Morris and
Robert L. Parter, which patent application has been accorded serial
number and claims the benefit under 35 U.S.C. 119 of U.S.
provisional patent application No. 60/111,624 filed Dec. 9, 1998
and No. 60/130,597 filed Apr. 22, 1999.
TECHNICAL FIELD
[0002] This invention relates generally to medical devices and more
particularly to needles that are curved for indirect infusion
access within the body.
BACKGROUND
[0003] Medical procedures involving the vertebrae are typically
complicated because of the preciseness required to avoid both
neural damage and injury to major blood vessels, as well as the
indirect path that is usually required to access the treatment
site.
[0004] This is certainly the case when performing a vertebroplasty,
a procedure whereby bone cement, most commonly methyl methacrylate,
is injected into a vertebral body to provide stabilization and/or
pain relief in selected patients having a spinal condition such as
osteolytic metastasis and myeioma, painful or aggressive hemangiome
(benign lesions of the spine), or painful osteoporotic vertebral
collapse.
[0005] Standard treatment practice depends on the region of the
spine being treated. For the cervical vertebrae, anterolateral
access is used with a 15 gauge needle. The large vessels adjacent
to the vertebra are laterally manipulated by the radiologist to
provide an access site between the vessels and the pharyngolarynx.
An upward access route is required because the needle must be
introduced below the mandible.
[0006] When accessing the thoracic or lumbar vertebrae, typically a
large 10 gauge needle is used following a transpedicular or
posterolateral approach. The transpedicular route is preferred to
avoid spinal nerve injury and to decrease the probability of the
cement leaking into tissues adjacent to the vertebral body.
[0007] To obtain complete fill of a damaged vertebral body, it is
often required that a second transpedicular access be made from the
opposite side. A single infusion usually cannot fill the entire
target area because the needle tip cannot be redirected from the
original plane of entry. Continued infusion of cement from the
first access site will usually not result in an adequate infusion
due to the tendency of the material to set before it fills all of
the affected area, thereby becoming a baffle to itself.
Furthermore, the thick density of the marrow and structures, such
as veins, usually acts to impede free flow of the cement within the
vertebral body.
[0008] Another concern during the procedure is accidental puncture
of the these veins. Because vertebral veins lead directly to the
lungs, there is a significant risk of pulmonary embolism if cement
is accidentally introduced therein.
[0009] The inability to adequately maneuver the needle cannula tip
within a body or around structures is a major limitation of the
straight needle. Additional needle sticks to complete a medical
procedure result in discomfort to the patient and additional risk
of leakage and other complications.
[0010] To sufficiently access a vertebral body for complete
infusion of cement, the needle tip must be capable of being
deflected at significantly large angles from the original axis.
This would require that the needle have a distal bend so that the
needle could be rotated to selectively direct the material.
[0011] Rigid curved needles are well known for suturing
applications; however, adding anything more than a slight bend to
an infusion needle limits its access path and ability to deeply
penetrate tissue, especially bone. For example, a rigid curved
needle is unsuitable for use in a vertebroplasty procedure where
the needle cannula must be driven through the bone and deep into
the vertebral body using a relatively straight approach and
maintained in place to avoid additional damage to the entry site.
While the initial needle access must be done with a straight needle
of sufficient strength to penetrate bone, the ideal approach would
be to direct a lateral infusion of cement following needle
penetration, and then to withdraw the needle along its original
path.
[0012] Accomplishing this is problematic. The tissue density and
resistance of the tissue to penetration at the treatment site can
require that the inner infusion member be nearly as stiff as the
outer piercing cannula. A certain degree of needle rigidity is
required in order to be able to maneuver the needle and accurately
direct flow of material.
[0013] While stainless steel needles having a slight distal bend
are known, the amount of needle curvature necessary to provide
adequate lateral infusion is not possible--the needle plasticly
deforms once inside the outer restraining cannula and hence is
unable to return resiliently to its preformed shape. Thus, a second
needle access would still be required to provide adequate
filling.
[0014] Other medical procedures present similar problems when a
single straight needle is used. One example is tumor ablation where
percutaneous ethanol injection is used to treat carcinoma of the
liver and kidney. Originally introduced as a palliative treatment
for inoperable hepatocellular carcinoma of the liver, ethanol
injection has now been shown to have curative potential comparable
to resection in many patients, especially for smaller tumors.
[0015] Practice has been to inject ethanol directly into masses
using a straight needle and to allow the ethanol to infuse from one
or more side holes into the tissue. The problem is that the
infusion may not penetrate any deeper than the needle tract; thus
portions of the tumor are not effectively treated. It is desirable
to provide a device for more effective infusion of ethanol into the
tumor mass.
SUMMARY OF THE INVENTION
[0016] The foregoing problems are solved and a technical advance is
achieved in an infusion needle made of rigid superelastic material
and having at least one performed bend along the distal portion of
its length. The needle is used as an inner cannula coaxially with a
second hollow cannula for restraining the inner needle cannula in a
substantially straight orientation during percutaneous introduction
to the target site, whereby the inner needle cannula is deployed to
resiliently return to its preformed configuration.
[0017] The ability of the preformed inner needle cannula to deflect
laterally upon exiting the outer cannula allows the inner needle
cannula to infuse or aspirate material at multiple points within
different planes in the body as the inner infusion needle rotates
about its longitudinal axis. This helps to reduce or eliminate the
need for additional "sticks" with the outer cannula; it also allows
the operator to make an entry from one direction, then to deploy
the curved inner cannula to reach a site that cannot be accessed
directly, such as where another structure lies along the access
path, thereby blocking the target site.
[0018] The preferred material for the inner cannula is a
superelastic, shape memory alloy such as sold under the trademark
Nitinol (Ni--Ti); however, there are other non Ni Ti alloys that
may be used. A Nitinol alloy is desirably selected that has
properties whereby the temperature at which the martensitic to
austenitic phase change occurs is lower than the working
temperature of the device (i.e. room temperature).
[0019] As described in U.S. Pat. No. 5,597,378, incorporated herein
by reference, a permanent bend may be heat set in a superelastic
Nitinol cannula by maintaining the cannula in the desired final
shape while subjecting it to a prescribed high temperature for a
specific time period. The resulting cannula can be elastically
manipulated far beyond the point at which stainless steel or other
metals would experience plastic deformation. Nitinol and other
superelastic materials when sufficiently deformed undergo a local
phase change at the point of stress to what is called
"stress-induced martensite" (SIM). When the stress is released, the
material resiliently returns to the austenitic state.
[0020] A second method of imparting a permanent bend to the needle
material is by a process commonly known as "cold working." Cold
working involves mechanically overstressing or overbending the
superelastic cannula. The material within the bending region
undergoes a localized phase shift from austenite to martensite and
does not fully return to its original shape. In the case of the
cold-worked cannula, the result is a permanent curve about the
bending zone which has been locked in to at least a partial
martensitic crystalline state.
[0021] In contrast, when heat treating is used, the entire
heat-annealed cannula is in a austenitic condition, even in the
curved region, and is only temporarily transformed to martensite
under sufficient bending stresses. Therefore, the flexural
properties of the annealed cannula vary little across its
length.
[0022] Conversely, the bend of a cold-worked cannula, which
contains martensite, has increased resistance to deformation and
therefore holds its shape better than the more flexible bend of the
pure austenitic cannula This increased rigidity can be an advantage
for certain clinical applications.
[0023] In one aspect of the invention, an introducer trocar or
stylet is used with either the outer or inner needle cannula,
depending on the luminate size of the needle, to facilitate access
to tissue and/or prevent coring tissue into the distal tip of the
needle device. The infusion needle or inner cannula is introduced
through the outer cannula after access has been established and the
trocar or stylet is removed.
[0024] Depending on the size of the cannulas, the degree of the
preformed bend, or the method used to form the bend, the inner
cannula or needle may slightly deform the outer cannula as the
preformed bend present in the inner needle or cannula is
constrained within the outer cannula. As a result, the outer
cannula may be deflected a few degrees from its normal longitudinal
axis at a point corresponding to the bend of the inner cannula. As
the inner cannula is deployed from the outer cannula, the inner
cannula deflects laterally until the entire region of the bend is
unsheathed. The distal opening of the inner cannula is oriented at
a large angle (preferably within the range of 60-90.degree.) from
the original longitudinal axis when the inner needle is fully
deployed.
[0025] The ability of the inner cannula to deflect at a significant
angle from the original longitudinal axis has great utility in a
number of applications where straight access is required followed
by redirection of the distal opening. This deflection permits
access to a different site without the necessity of withdrawing and
reintroducing the needle.
[0026] A primary example of such a procedure is vertebroplasty in
which infusion of the stabilizing cement with a straight needle
often requires a second stick to provide complete filling to
stabilize the vertebral body while avoiding damage to delicate
structures such as veins. As with the standard single-needle
procedure involving the thoracic or lumbar regions of the spine, a
transpedicular approach is normally used whereby the larger outer
needle cannula, such as a coaxial Jamshldi-type needle, is
introduced into the damaged or diseased vertebral body. The outer
needle includes an inner introducer trocar which is then replaced
with a inner curved needle for infusion of the cement.
[0027] The ability of the curved needle to deflect laterally and
rotate to reach multiple planes gives it a significant advantages
over straight needles which have a limited range of movement.
Because of this additional range of movement, the curved needle can
usually complete the vertebroplasty procedure with a single access
of the vertebral body. This avoids additional discomfort and risks
to the patient, which include complications from leakage of cement
or inadvertent infusion into non-target areas.
[0028] In addition to using the coaxial needle for infusion of
cement as above, the device can also be adapted for aspirating
material or serving as a conduit for the introduction of other
devices. The apparatus may be used for a percutaneous corpectomy, a
procedure which involves fusion and decompression of two or more
vertebrae by first aspirating tissue from the damaged vertebral
bodies, then introducing a prosthesis having a carbon fiber
composite cage packed with bone graft material to serve as
scaffolding for the affected vertebrae. Once the cage is properly
positioned, methyl methacrylate or another suitable material is
infused into the vertebral bodies to secure the prosthesis. The
percutaneous corpectamy offers less trauma, and with the
reinforcement cage, provides superior rigidity over a conventional
corpectomy utilizing bone graft material alone.
[0029] In another aspect of the invention, the coaxial needle can
be adapted for paraspinal use to inject medicaments within the
neural canal or epidural space as part of management and/or
diagnosis of pain. Preferably, the outer cannula has a tip adapted
for piercing soft tissue. This outer needle cannula, preferably
about twenty-one (21) gauge, is introduced percutaneously parallel
to the spinal column along with an internal stylet with matched
bevel to prevent coring tissue into the distal opening. The stylet
is removed and the curved needle, about twenty-five (25) gauge, is
inserted into the outer cannula. The needle assembly is then
maneuvered to contact a nerve root during a diagnostic procedure to
help recreate pain symptoms of the patient. The inner infusion
needle also includes a stylet which is situated within the
passageway of the needle as it is directed to the target site. The
stylet is then removed from the infusion needle and medicaments,
commonly steroids such as celestone (injected with lidocaine),
kenalog, or methylprednisone are introduced to the treatment site.
The inner needle is then withdrawn into the outer sheathing cannula
and both are withdrawn from the patient.
[0030] Another use of the smaller gauge paraspinal needle is for
diskography which consists of injecting a contrast agent
(preferably nonionic contrast media) directly into the patient's
disk to delineate the extent of any malformation or injury to the
vertebral body.
[0031] Yet another aspect of the invention solves the problem of
infusion of ethanol into a tumor mass by utilizing a plurality of
curved needle cannulae deployed within an cannula introduced into
the tumor where the curved needle cannulae radiate outward into an
umbrella-shaped configuration. Infusion can take place at multiple
points within the tumor to provide wider dispersion of the ethanol.
Following treatment, the curved needle cannulae are withdrawn into
the cannula and the device is removed from the patient.
[0032] In a related aspect, one or more needle cannulae are located
proximal to the distal end of the infusion needle. These
proximally-located cannulae allow infusion of medicaments at
different points along the length of the device. By having multiple
sets of needles arranged in the umbrella configuration, the volume
of tissue treated is increased. The coaxial outer cannula includes
a plurality of side apertures that allow the proximally-located
needle cannulae to deploy after the infusion needle is placed at
the desired location in the body and the outer cannula is
withdrawn. An outer sheath over the coaxial outer cannula
selectively exposes the side apertures to permit the appropriate
alignment of needle cannulae and apertures when there are multiple
rows of each.
[0033] The invention has applicability in any clinical situation
where a straight approach is dictated and there is a need to avoid
an obstructing structure (a large vessel, bowel loop, etc.) in the
entry path, or the need to redirect the approach to a more lateral
pathway to infuse medicaments or aspirate, such as to drain an
abscess.
[0034] In addition to infusion or aspiration, the invention can
provide a conduit for introducing and/or directing the path of
other medical devices within the body such as radio-frequency
ablation catheters or wire guides. This would allow a straight
approach to a critical juncture whereafter the curved infusion
needle can be deployed to precisely proceed to the desired
anatomical site, especially in situations such as a luminal
bifurcation or when access to an ostium is required.
[0035] Another use of the invention is to place the infusion needle
in a bronchoscope or colonoscope which can serve as the outer
constraining device. Under visualization, the inner needle then can
be directed to perform a biopsy or other type of procedure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is an isometric view of an illustrative embodiment of
the curved needle inner cannula;
[0037] FIG. 2 is a top view of an outer needle cannula with an
introducer trocar and the inner curved needle cannula;
[0038] FIG. 3 is a top view of the assembly of the inner curved
needle cannula inside the outer needle cannula;
[0039] FIG. 4 is an exploded isometric view of a second embodiment
of the inner and outer cannula;
[0040] FIG. 5 depicts a pictorial view of the inner cannula of FIG.
4 with an introducer stylet;
[0041] FIG. 6 is a side view of the inner cannula of FIG. 4 being
initially deployed from the outer cannula;
[0042] FIG. 7 is a side view of the inner cannula of FIG. 4 being
further deployed from the outer cannula;
[0043] FIG. 8 is a side view of the inner cannula of FIG. 4 being
still further deployed from the outer cannula;
[0044] FIG. 9 is a partially sectional view depicting the apparatus
of FIG. 2 being introduced into a vertebral body;
[0045] FIG. 10 is a partially sectional view similar to FIG. 9,
depicting of the apparatus of FIG. 2 infusing cement into a
vertebral body.
[0046] FIG. 11 is a broken, partially sectioned view similar to
FIGS. 9 and 10, depicting of the apparatus of FIG. 2 infusing
additional cement into a vertebral body.
[0047] FIG. 12 is an isometric view of a third embodiment of the
apparatus;
[0048] FIG. 13 is a side view of the multi-directional infusion
needle illustrated in of FIG. 12;
[0049] FIG. 14 is a broken, side view of the needle of FIG. 13
partially showing the needle deployed;
[0050] FIG. 15 is a side view of a trocar introducer used with the
embodiment of FIG. 12;
[0051] FIG. 16 is a side view of the proximal assembly portion of
the apparatus illustrated in FIG. 12;
[0052] FIG. 17 is a side view of a fourth embodiment of the
apparatus;
[0053] FIG. 18 is a broken, partially-sectioned side view of the
apparatus illustrated in FIG. 17 prior to deployment;
[0054] FIG. 19 is a transverse cross-sectional view of coaxial
outer cannula depicted in FIG. 17;
[0055] FIG. 20 depicts cross-sectional views of two embodiments of
coaxial outer cannula depicted in FIG. 17;
[0056] FIG. 21 is an isometric view of a fifth embodiment of the
present apparatus; and
[0057] FIG. 22 is an isometric view similar to that of FIG. 21
showing the apparatus fully deployed.
DETAILED DESCRIPTION
[0058] FIG. 1 depicts a needle assembly 10 comprising an infusion
needle 11 with a preformed bend 16 for lateral infusion or
aspiration of medicaments and other materials. As defined herein,
the "needle assembly 10" can comprise infusion needle 11 alone or
infusion needle 11 in combination with other components. The
"infusion needle 11" as defined herein comprises one or more needle
cannulae having a preformed bend 16.
[0059] The infusion needle 11 of FIG. 1 is comprised of a
superelastic alloy needle cannula 13, preferably the alloy sold
under the trademark Nitinol, that is soldered or otherwise affixed
to a well-known needle hub 14 using one of a selected number of
well-known techniques, including that of Hall described in U.S.
Pat. No. 5,354,623 whose disclosure is expressly incorporated
herein by reference, and a flange 23 which has a first tapered or
pointed end 24 whose shape is readily distinguishable from the
second, squared end 42.
[0060] First end 24 corresponds to the direction of preformed bend
16 in needle cannula 13 of infusion needle 11. Bend 16 is formed in
the Nitinol needle cannula 13 by either the well-known process of
deforming the cannula under extreme heat for a prescribed period of
time, which produces a cannula entirely in the austenitic state, or
by cold working the cannula, which involves applying a large amount
of mechanical stress to deflect the 15 cannula well beyond the
desired amount of permanent bend. Cold working permanently locks a
crystalline structure in the bending zone into at least a partial
martensitic condition while the unstressed portions of the cannula
remain in the austenitic state.
[0061] Cold worked Ni--Ti alloys are discussed in "Linear
Superelasticity In Cold-Worked Ni--Ti", (Zadno and Duerig) pp. 414
to 419, in Engineering Aspects of Shape Memory Alloys,
Butterworth-Heineman, Boston, Mass. (Duerig et al, editors) which
is incorporated herein by reference. In addition to Nitinol,
superelastic or pseudoelastic copper alloys, such as Cu--Al--Ni,
Cu--Al--Zi, and Cu--Zi, are available as alternative needle cannula
materials. Flexible polymeric materials with sufficient rigidity
for both deployment and shape memory to assume a desired curve may
also be used in certain applications, either alone or in
combination with reinforcing metal components such as a metal braid
or tip.
[0062] Preformed bend 16 of infusion needle 11 forms a distal
portion of needle cannula 13, preferably close to about 25% of the
length of needle cannula 13 in the embodiment shown in FIG. 1. The
large size of the infusion needle, preferably 10 to 18 gauge, makes
this particular embodiment suitable for penetrating a vertebral
body to perform a vertebroplasty or percutaneous corpectomy
procedure. A more preferred range is 12 to 17 gauge, with the most
preferred cannula size being 13 to 15 gauge.
[0063] With regard to a vertebroplasty and corpectomy procedures,
the larger gauge cannula has both the strength to penetrate dense
bone material as well as a sufficient lumen diameter to aspirate
material from the vertebral body and to infuse highly viscous bone
cement, such as methyl methacrylate. The preferred preformed bend
16 of the infusion needle 11 has a constant radius. For the
embodiment of FIG. 1, the preferred radius of distal bend 16 is
approximately 3.0 cm for a 13 gauge needle, and approximately 2.5
cm for a 14 gauge needle. Although the illustrative embodiment has
a constant bend radius, an increasing or decreasing radius bend
could be employed for certain clinical applications. Furthermore,
it is possible to introduce more than one bend into the
superelastic cannula for applications requiring a special needle
configuration.
[0064] The primary purpose of using a Nitinol or other superelastic
alloy cannula is that the cannula can be constrained into one shape
during passage to the treatment site, then deployed into the
preformed configuration without experiencing any plastic
deformation.
[0065] FIG. 2 depicts a pair of needles to be used coaxially in
that manner, including the infusion needle 11 of FIG. 1 and a
coaxial outer cannula 12 for maintaining inner infusion needle 11
in a substantially straight configuration while being introduced to
the treatment site. The embodiment depicted in FIG. 2 is
Jamshidi-type needle (Manan Inc., Northbrook, Ill.) which is a
two-part needle assembly 43, and is most commonly used for
accessing dense, hard tissue such as bone, fibrous material, etc.
Thus, it is well suited for penetrating the wall of a vertebral
body wherein the infusion needle 11 can be deployed.
[0066] The two-part needle assembly 43 includes a coaxial outer
cannula 12 having a stainless steel cannula 19 with an inner
passageway 21 that is sufficiently large to accommodate inner
infusion needle 11. For example, the standard 11 gauge
Jamshidi-type needle suitable for accessing a vertebral body would
be used with thirteen (13) gauge inner curved needle. Stainless
steel cannula 19 is affixed proximally to a handle 26 and a
connector hub 31 (shown in FIG. 3). The connector hub 31 receives
the second part of the two-part needle assembly 43, the coaxial
outer cannula introducer 52 which preferably comprises a trocar 25.
The trocar hub 27 locks into handle 26 of coaxial outer cannula 12.
The beveled tip 30 of trocar 25 extends approximately 5 mm beyond
the distal tip 22 of coaxial outer cannula 12 and assists in
penetration. Trocar 25 also serves to prevent the coaxial outer
cannula 12 from coring a sample of bone or other material during
access.
[0067] After outer needle assembly 43 has been directed to the
target site, trocar 25 is removed from coaxial outer cannula 12 and
infusion needle 11 is inserted into passageway 21 of the coaxial
outer cannula 12, as shown in FIG. 3. To maintain openness of the
infusion needle passageway 15 and to prevent tissue coring during
deployment, an inner needle introducer stylet 46 can be introduced
coaxially inside the infusion needle. Inner needle introducer
stylet 45 includes a handle 83 and a shaft 46 which is made of a
flexible, high-tensile. polymeric material such as
polyetherethylketone (PEEK) to allow stylet 45 to assume the
contour of preformed bend 16 after deployment.
[0068] Inner infusion needle 11 straightens as it is loaded into
coaxial outer cannula 12. As the portion including preformed bend
16 of infusion needle 11 extends out from tip 22 of coaxial outer
cannula 12 as depicted in FIG. 3, infusion needle 11 assumes the
preformed shape due to the superelastic properties of needle
cannula 13. For infusion, inner needle introducer stylet 52, which
helps prevent coring of tissue into passageway 21 of coaxial outer
cannula 12, is removed. The tapered or "arrow" end 24 of flange 23
of proximal hub 14 corresponds with the deflection plane 29 of
infusion needle 11.
[0069] By maneuvering flange 28, the inner curved needle 13 can be
rotated in either direction 28 to reorient the plane of deflection
29 and place the tip opening 17 at multiple locations within the
area being treated.
[0070] In FIG. 3, tip 17 is deflected at an angle 44 of
approximately 60.degree. to 70.degree. from the device longitudinal
axis 18. This gives, for example, with a thirteen (13) gauge
infusion needle 11, a lateral reach, measured from tip 17 to
longitudinal axis 18, of nearly thirty (30) millimeters in any
direction.
[0071] While the degree of deflection required is determined by the
application and desired lateral reach of the device, it is also
limited by the size of the cannula if the permanent bend is cold
worked into the material. Cold working provides a stiffer bend
which can be advantageous in certain applications such as
vertebroplasty and biopsy of dense tissue; it is more difficult to
permanently deform a larger gauge Nitinol cannula without
application of extreme heat. For the embodiments contemplated, the
angle of deflection 44 can encompass a range of 30.degree. to
110.degree., with a preferred range of 40 to 90.degree. for most
applications.
[0072] FIG. 4 depicts a second version of the inner curved needle
and sheathing outer needle adapted for use in the injection of
medicaments, contrast media, or other non-viscous agents. The
infusion needle 11 is comprised of a smaller gauge needle cannula
13, preferably around twenty-five (25) gauge, mounted to a proximal
hub 14. The preformed bend 16 of individual needle cannula 13 has a
slightly tighter radius than that illustrated in FIGS. 1 through
3.
[0073] Still referring to FIG. 4, the coaxial outer cannula 12
includes a correspondingly sized needle cannula 19, preferably
around twenty-one (21) gauge, attached to a standard needle hub
that is adapted to receive proximal hub 14 of infusion needle 11.
The embodiment of FIG. 4 is used with a plurality of stylets that
are inserted within both the inner and outer needles during their
respective introduction into the body. The first is an outer
cannula introducer stylet 52 that is inserted into the passageway
21 of coaxial outer cannula 12. The coaxial outer cannula 12 and
outer cannula introducer stylet 52 are inserted together into the
patient. The stylet, which is preferably a stainless steel stylet
wire 46 with an attached standard plastic needle hub 47, prevents
the coaxial outer cannula 12 from coring tissue into passageway 21
at distal tip 22.
[0074] Once coaxial outer cannula 12 is in position, outer cannula
introducer stylet 52 is withdrawn from coaxial outer cannula 12 and
infusion needle 11 and second introducer stylet 45 are inserted
together into outer needle passageway 21. The inner needle
introducer stylet 45, which is longer than outer cannula introducer
stylet 52 in order to fit the longer infusion needle 11, serves a
similar function to the outer cannula introducer stylet 52 by
preventing coring of tissue when infusion needle 11 is deployed
from coaxial outer cannula 12.
[0075] As illustrated in FIGS. 4 and 5, proximal hub 14 of infusion
needle 11 is adapted such that hub 53 of inner needle introducer
stylet 45 locks together with proximal hub 14 to keep the two in
alignment. This locking mechanism includes a molded protuberance 49
on hub 53 that fits within a recess 50 on proximal hub 14. The
purpose of maintaining alignment of hub 53 and proximal hub 14 is
to match the beveled surface 51 at the tip of the inner needle
introducer stylet 45, shown in FIG. 5, with the beveled edge at the
tip 17 of infusion needle 11.
[0076] FIGS. 6 through 8 depict the deployment of infusion needle
11 from within outer needle cannula 12. FIG. 6 shows infusion
needle 11 during initial deployment from coaxial outer cannula 12.
The preformed bend 16 of the infusion needle 11 is constrained by
the cannula 19; however, as illustrated in FIG. 6, preformed bend
16 may be of sufficient stiffness to slightly deform outer cannula
19 while infusion needle 11 is inside coaxial outer cannula 12.
Despite this slight deformation, coaxial outer cannula 12 is still
substantially straight.
[0077] As depicted in FIG. 7, stress preformed bend 16 places on
outer cannula 19 relaxes as infusion needle 11 is further deployed
and the angle of deflection 44 (measured from longitudinal axis 18
of coaxial outer cannula 12 to the opening at tip 17 of infusion
needle 11) is increased. As infusion needle 11 is further deployed
as depicted in FIG. 8, fully exposing preformed bend 16 to produce
the largest angle of deflection 44, the unstressed outer cannula
returns to a straight configuration.
[0078] The phenomenon depicted in FIGS. 6 through 8 is most
noticeable when using smaller gauge cannulae, such as shown in
FIGS. 4 and 5. The larger gauge outer cannula of FIGS. 1 to 3 is
more resistant to deformation than that of FIGS. 4 and 5.
Naturally, the tendency of the stressed outer cannula to deform is
also very much dependent on the stiffness and radius of the
preformed bend 16 as well as the thickness of the cannula wall and
material used. To eliminate this deformation during introduction of
the device into the body, stylet 45, as depicted in FIG. 5, can be
used as a stiffener until removed immediately before the portion
having preformed bend 16 is deployed.
[0079] FIGS. 9 through 11 depict the use of the device illustrated
in FIG. 3 to perform a vertebroplasty procedure on a pathological
vertebral body 33 using a transpedicular approach. As depicted in
FIG. 9, coaxial outer cannula 12 with introducer trocar 25 is
introduced through the wall 38 and into the marrow 37 of the
vertebral body 33. The transpedicular route of access places the
needle between the mammillary process 34 and accessory process 35
of the vertebral arch 55. The vertebral arch 55 is attached
posteriorly to the vertebral body 33 and together they comprise the
vertebra 54 and form the walls of the vertebral foremen 36.
[0080] Once coaxial outer cannula 12 and inner introducer trocar 25
are within the internal region or marrow 37 of the vertebral body,
trocar 25 is withdrawn from the coaxial outer cannula 12 and
infusion needle 11 is inserted in its place. FIG. 10 depicts
infusion needle 11 infusing bone cement 41, commonly methyl
methacrylate, into vertebral body 33 to provide it with improved
structural integrity. As depicted in FIG. 11, infusion needle 11
can be partially withdrawn or rotated to obtain more complete
filling or to avoid the network of vertebral veins. Even though the
vertebral body may not need to be completely filled, the density of
marrow 37 would still necessitate a second transpedicular stick in
the absence of the instant apparatus infusing cement within
multiple planes within vertebral body 33. Upon completion of the
procedure, infusion needle 11 is withdrawn back into coaxial outer
cannula 12 and both are removed from vertebral body 33.
[0081] The utility of the hollow, curved superelastic needles is
certainly not limited to procedures involving the spine. Such
needles are useful at many sites within the body that might require
straight access by a needle, followed by indirect or lateral
infusion, aspiration, or sampling. For example, the inner needle
could be adapted to take biopsy samples from dense tissue, such as
a breast lesion, especially where indirect access is might be
desirable.
[0082] FIG. 12 is an isometric view of hollow, curved superelastic
needles in which needle assembly 10 comprises a multiple needle
assembly 70 useful in infusion of ethanol or other medicaments into
a tumor. In FIG. 12, needle assembly 10 comprises an infusion
needle 11, which includes a multiple needle assembly 70 comprising
a plurality of needle cannulae 13, each having a preformed bend 16,
a proximal assembly 58 for constraining the multiple needle
assembly 70, and a coaxial outer cannula 12 for introducing the
multiple needle assembly 70 to its anatomical target.
[0083] The multiple needle assembly 70 in FIG. 13 includes a base
cannula 56 affixed to a proximal hub 14 such as a standard female
luer fitting. A plurality of needle cannulae 13 are manifolded into
base cannula 56, preferably evenly spaced in an umbrella
configuration 75, and affixed in place with a solder joint 57. In
the structure illustrated in FIG. 12, five needle cannulae 13 are
used; from two to as many as appropriate for the given cannula size
can be used. As with the other versions, needle cannulae 13 are
preferably made of Nitinol that is either annealed or cold-worked
to produce the preformed bend 16. In the structure illustrated in
FIG. 12, the coaxial outer cannula 12 has an outer diameter of
approximately 0.072 inches and an inner diameter of around 0.06
inches, while the individual curved needle cannulae 13 have an
outer diameter of 0.02 inches and an inner diameter of about 0.12
inches. As shown in FIG. 14, the tips 17 of the needle cannulae 13
may be beveled to better penetrate tissue.
[0084] Deployment of curved needle cannulae 13 of multiple needle
assembly 70 is depicted in FIG. 14. Needle cannulae 13 are
restrained by coaxial outer cannula 12 until multiple needle
assembly 70 is advanced, exposing the distal end portions of needle
cannulae 13 at distal end 22 of coaxial outer cannula 12, whereby
they radiate outward to assume, when fully advanced, the umbrella
configuration 75 shown in FIG. 13.
[0085] FIG. 15 depicts a side view of an outer needle assembly
comprising a coaxial outer cannula 12 and outer cannula introducer
stylet 52 used in placement of the multiple needle assembly 70 of
FIGS. 12 through 14. The outer cannula introducer stylet 52 is
inserted into passageway 21 of coaxial outer cannula 12 with the
male proximal hub 47 of the outer cannula introducer stylet 52
fitting into the female proximal hub 20 of coaxial outer cannula 12
when the outer cannula introducer stylet 52 is fully advanced.
Outer cannula introducer stylet 52 includes a sharp tip 63, such as
the diamond-shape tip depicted, for penetrating tissue.
[0086] The outer cannula introducer stylet 52 and coaxial outer
cannula 12 may be introduced percutaneously into the liver or
kidney and placed at the desired treatment location. The outer
cannula introducer stylet 52 is then removed. The proximal assembly
58 with the preloaded multiple needle assembly is then advanced
into the coaxial outer cannula 12 which remains in the patient. In
the version illustrated in FIGS. 12 through 15, the coaxial outer
cannula preferably has an outer diameter of about 0.095 inches and
an inner diameter of about 0.076 inches, while the outer diameter
of the inner stylet is preferably about 0.068 inches.
[0087] FIG. 16 a side view of the proximal assembly 58 shown of
FIG. 12. The Proximal assembly 58 includes a distal male adaptor 60
connected to an intermediate cannula 59 that is sufficiently large
to accommodate multiple needle assembly 70. At the proximal end of
the intermediate cannula 59 is proximal assembly female adaptor 61
which is connected proximally to a proximal assembly hub 62, such
as a Tuohy-Borst adaptor. Proximal assembly hub 62 is utilized by
the physician during manipulation of the device.
[0088] The multiple needle assembly 70 of FIG. 13 is loaded into
lumen 64 at the proximal end 65 of the proximal assembly hub 62,
with the needle cannulae 13 remaining within intermediate cannula
59. Distal end 66 of proximal assembly 58 with preloaded multiple
needle assembly 70 is then inserted into proximal hub 20 of the
coaxial outer cannula as depicted in FIG. 12. The multiple needle
assembly 70 is then advanced from the proximal assembly 58 into the
coaxial outer cannula 12 where it is deployed as depicted in FIGS.
12 to 14. Ethanol is infused into multiple needle assembly 70 via
the proximal hub 14 of the infusion needle 11. Following treatment,
the multiple needle assembly 70 is withdrawn into coaxial outer
cannula 12 and the entire needle assembly 10 is removed from the
patient.
[0089] FIGS. 21 and 22 depict a variation of needle assembly 10 of
FIG. 12 in which infusion needle 11 and coaxial outer cannula 12
are connected to a coaxial handle 76 used to advance and deploy
multiple needle assembly 70 releasably from constraint of coaxial
outer cannula 12. As shown, coaxial handle 76 comprises a
stationary outer component 77 that fits over base cannula 56 of
multiple needle assembly 70 and attaches to proximal hub 20. A
slidable inner component 78 further comprises a thumb piece 79 used
by the physician to advance or retract the coaxial outer cannula 12
as the slidable inner component 78 retracts into stationary outer
component 77.
[0090] In FIG. 21, the needle assembly is depicted in the
introducer postion with the thumb piece 79 advanced fully forward
within a slot 80 in outer slidable component 77.
[0091] FIG. 22 depicts the deployment state of needle assembly 10
in which thumb piece 79 has been moved to the most proximal
position within slot 80. In this position, coaxial outer cannula 12
is retracted to fully expose the plurality of needle cannulae 13
which can assume their unconstrained configuration with the
preformed bends 16.
[0092] This type of handle can be used with both the multiple and
single infusion needle where a introducer trocar or stylet is not
required. Other well-known types of coaxial handles 76 include, but
are not limited to, screw-type, rachet-type, or trigger-activated
handles which allow coaxial outer cannula 12 to be longitudinally
displaced relative to infusion needle 11. To reduce the need for a
trocar or stylet for facilitating tissue penetration, distal tip 22
of coaxial outer cannula 12 can be shaped into a needle point such
as depicted, or into a non-coring point to help maintain an open
outer cannula passageway 21.
[0093] A syringe or other reservoir container can be attached to
proximal hub 14 as an infusate source or for collection of
aspirated material. In addition, a reservoir, such as a syringe,
can be incorporated internally within coaxial handle 76 of needle
assembly 10 or integrally attached thereto.
[0094] Another version of multiple needle assembly 70 is depicted
in FIGS. 17-20 whereby there are one or more groupings of
proximally-located needles 73 in addition to the distally-located
needles 74 that are similar to those illustrated in of FIG. 12. By
locating the additional needle cannulae 13 proximal to those at the
distal end, wider dispersal and coverage is attained for infusion
of medicaments.
[0095] In the version illustrated in FIG. 17, there is an
arrangement of four needle cannulae comprising the distally-located
needles 74, while at least one other group comprising
proximally-located needles 73 located along the length of infusion
needle 11 provides for simultaneous infusion in a more proximal
location. The needle cannulae 13 of the proximally-located and
distally-located needles 73, 74 can vary in configuration, length,
number, and how they are attached to a base cannula 56 such as that
shown in FIG. 13. For example, individual needle cannulae 13 within
an umbrella configuration 75 or between proximally-located and
distally-located needles 73, 74 can be longer, or have a different
radius than others, to vary the distribution pattern of the
infusate.
[0096] As depicted in FIGS. 17 and 18, each pair of
oppositely-disposed needle cannulae 13 within a grouping of four
proximally-located needles 73 are longitudinally offset with
respect to the adjacent pair located ninety degrees (90.degree.)
therefrom, as are the side apertures 67 from which they emerge.
With regard to attachment, possibilities include, but are not
limited to, having all needle cannulae 13 attaching to a single
base cannula 56; dividing base cannula 56 such that a separate
portion extends distally from the proximally-located needles 73 to
join the distally-located needles 74, or eliminating the base
cannula 56 such that needle cannulae 13 of multiple needle assembly
70 are separate and run the length of infusion needle 11.
[0097] To constrain needle cannulae 13 for introduction along a
single pathway into the body, a coaxial outer cannula 12 is used
that has side apertures 67 in the cannula to permit the
proximally-located needles 73 to deploy outward therethrough for
lateral infusion. FIG. 18 shows a sectioned view of the needle
assembly of FIG. 17 in which the needle cannulae 13 are constrained
in the introduction position. An introducer cannula 68 is used to
selectively expose side apertures 67 in versions where the
arrangement of needles is such that individual needle cannulae 13
may prematurely exit a non-designated hole or row, preventing or
delaying proper deployment of the multiple needle assembly 70. By
maintaining the introducer sheath over side apertures 67 until
distally-located needles 73 are deployed, proper deployment of all
needle cannulae 13 is easier.
[0098] FIGS. 19 and 20 illustrate intraluminal guides 69 to help
facilitate proper alignment of needle cannulae 13 with a designated
side aperture 67. In FIG. 19, a series of ridges 71 within
passageway 21 of coaxial outer cannula 12 guide the needle cannulae
13 to align with a designated side aperture 67. FIG. 20 depicts an
alternative intraluminal guide 69 in which the needle cannulae 13
travel longitudinally within grooves 72 formed in the inner wall of
passageway 21.
* * * * *