Surgery – Instruments – Means for concretion removal
Reexamination Certificate
1997-08-18
2002-09-10
Smith, Jeffrey A. (Department: 3732)
Surgery
Instruments
Means for concretion removal
Reexamination Certificate
active
06447523
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a device or apparatus for manipulating matter within a confined or inaccessible space, especially during surgery in a living body.
2. Description of the Prior Art
Matter may be manipulated in such circumstances in various ways, for example by application of a ligature, by suturing, by cutting with a knife or scissor action, or by capture and retrieval in devices such as screens, baskets, barriers, pouches, or retractors. Such manipulation may be difficult when operating in the confined space of a very deep wound or through a small arthroscopic or other endoscopic incision or body aperture.
Many forms of apparatus for performing surgical operations have been proposed previously using flexible steel wires which spring apart when extended from the distal end of a tube and which can be brought together again on withdrawal back into the tube. Examples of such known devices may be seen in U.S. Pat. Nos. 2,114,695, 2,137,710, 2,670,519, 3,404,677, 4,174,715, 4,190,042, 4,222,380, 4,249,533, 4,347,846, 4,655,219, 4,691,705, 4,741,335, 4,768,505 and 4,909,789. However, these devices may not be completely satisfactory for various reasons, especially after repeated use or long storage which may fatigue the materials used.
Attempts have been made to use shape memory metals in surgical apparatus, but these suffer from inconvenience and from the risk of damage to living tissues resulting from the need either to cool the memory metal while positioning it in the body so that body heat thereafter actuates the shape memory effect, or to heat the metal above body temperature to actuate it after positioning. Examples of such attempts are described in U.S. Pat. Nos. 4,509,517, 3,868,956 and 4,425,908.
SUMMARY OF THE INVENTION
The present invention uses pseudoelastic materials, preferably pseudoelastic shape memory alloys, which bend pseudoelastically to perform manipulations which may be difficult or impossible to achieve reliably with previously known devices. Pseudoelastic alloys have previously been described for non-manipulative devices such as lesion marker probes, bone anchors, heart valves, intrauterine devices, dental arch wire, coil stents and filters, as described in U.S. Pat. No. 4,665,906 (Jervis), U.S. Pat. No. 4,616,656 (Nicholson), U.S. Pat. No. 4,898,156 (Gatturna), U.S. Pat. No. 4,899,743 (Nicholson), and U.S. Pat. No. 4,946,468 (Li). In one case, U.S. Pat. No. 4,926,860 (Stice) describes a straight suturing needle made of such alloy which ensures the needle emerges straight after being inserted through a curved cannula. None of these known uses in any way suggests the present ingenious use of the power of pseudoelastic bending on extending a pseudoelastic manipulator means from a cannula to perform manipulations in difficult locations.
The present invention accordingly provides a device or apparatus for manipulating matter in a confined or inaccessible space, comprising
(i) manipulator means at least partly constructed of one or more bent or twisted elongate shape memory alloy members having pseudoelasticity at the intended manipulation temperature, and
(ii) a hollow housing (preferably of elongate tubular form) or cannula capable of holding at least the shape memory alloy member(s) in a relatively straightened state, and
(iii) actuating means for extending the shape memory alloy member(s) from the housing to manipulate matter within the said space and for withdrawing the shape memory alloy member(s) into the housing, the arrangement being such that the shape-memory alloy member(s) bend(s) or twist(s) pseudoelastically in a lateral or helical sense to manipulate the matter on extending from the housing at the said manipulation temperature, and become(s) relatively straightened on withdrawal into the housing at the said temperature.
Preferably the invention provides such a device or apparatus which is of elongate form for surgical manipulation of matter within a living body, and which has the manipulator means at Its distal end with the shape memory alloy member(s) having pseudoelasticity at the temperature to be encountered within that body, and wherein the actuating means is operable from the proximal end of the device.
Various forms of device or apparatus will now be described independently, it being understood that all may be inventive in themselves, although all are preferably within the scope of at least the first (more preferably both) of the two immediately preceding paragraphs. Non-surgical uses may be appropriate for some forms.
Any elastic material may be used in some of the embodiments of this invention, but it is generally preferred to use a pseudoelastic material. Many different materials exhibit pseudoelasticity and can be used in any embodiment of this invention. It is preferred to use a pseudoelastic shape memory alloy.
The term “elastic material” is used herein to mean a material that has spring-like properties, that is, it is capable of being deformed by an applied stress and then springing back, or recovering, to or toward Its original unstressed shape or configuration when the stress is removed. The elastic material is preferably highly elastic. The material can be polymeric or metallic, or a combination of both. The use of metals, such as shape memory alloys, is preferred. Shape memory alloys that exhibit pseudoelasticity, in particular superelasticity, are especially preferred. The elastic materials herein exhibit greater than 1% elastic deformation, more generally greater than 2% elastic deformation. Preferably, the elastic materials herein exhibit greater than 4% elastic deformation, more preferably greater than 6% elastic deformation.
Preferably, the elastic member is at least partially formed from a pseudoelastic material, such as a shape memory alloy that exhibits pseudoelasticity. Shape memory alloys which exhibit superelasticity (also referred to in the literature as non-linear pseudoelasticity), are especially preferred.
U.S. Pat. No. 4,935,068 to Duerig, which is commonly assigned with the present application and incorporated herein by reference, teaches the fundamental principles of shape memory alloys. Some alloys which are capable of transforming between martensitic and austenitic phases are able to exhibit a shape memory effect. The transformation between phases may be caused by a change in temperature. For example, a shape memory alloy in the martensitic phase will begin to transform to the austenitic phase when its temperature rises above As and the transformation will be complete when the temperature rises above A
f
. The forward transformation will begin when the temperature drops below M
s
and will be complete when the temperature drops below M
f
. The temperatures M
s
, M
f
, A
s
, and A
f
define the thermal transformation hysteresis loop of the shape memory alloy.
Under certain conditions, shape memory alloys exhibit pseudoelasticity, which does not rely on temperature change in order to accomplish shape change. A pseudoelastic alloy is capable of being elastically deformed far beyond the elastic limits of conventional metals.
The property of pseudoelasticity of certain shape memory alloys, which preferably is used in the devices of this invention, is the subject of a paper entitled “An Engineer's Perspective of Pseudoelasticity”, by T. W. Duerig and R. Zadno, published in Engineering Aspects of Shape Memory Alloys, page 380, T. W. Duerig, K. Melton, D. Stoeckel, and M. Wayman, editors, Butterworth Publishers, 1990 (proceedings of a conference entitled “Engineering Aspects of Shape Memory Alloys”, held in Lansing, Mich. in August 1988). As discussed in the paper, the disclosure of which is incorporated herein by reference, certain alloys are capable of exhibiting pseudoelasticity of two types.
“Superelasticity” arises in appropriately treated alloys while they are in their austenitic phase at a temperature which is greater than A
s
and less than M
d
(A
s
is the temperature at which, when a shape memory alloy in its martensitic phase is heated, the t
Buhler Michael
Jervis James E.
Middleman Lee M.
Poncet Philippe
Pyka Walter R.
Medtronic Inc.
Smith Jeffrey A.
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