Surgery – Instruments – Surgical mesh – connector – clip – clamp or band
Reexamination Certificate
1999-01-07
2001-01-30
Thaler, Michael H. (Department: 3731)
Surgery
Instruments
Surgical mesh, connector, clip, clamp or band
Reexamination Certificate
active
06179850
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
This invention relates generally to the field of medical devices, and more particularly to an apparatus and method for modulating flow in biological conduits automatically and remotely.
2. Description of the Background
Invasive medical procedures subject blood vessels to the risk of perforation leading to hemorrhage. Such hemorrhage often obscures the actual site of vessel damage and thereby impedes expeditious repair of the damage. In surgery, when a blood vessel bleeds profusely, the usual method of controlling the bleeding is to evacuate blood from the surgical field so that the operator may visualize the site of hemorrhage and directly repair the damage. Methods of repair range from sacrifice of the blood vessel using ligatures or cautery to repair of the vessel wall using microsurgical techniques.
If bleeding is profuse, the process of hemorrhage leads to a vicious cycle in which as hemorrhage continues, the actual site of blood extravassation is more difficult to visualize due to blood obscuring the field. Fortunately, in many open surgical procedures, suction and irrigation devices are sufficient to help the surgeon stop the bleeding.
However, in certain procedures, such as repair of intracranial aneurysms and endoscopic surgery, suction and irrigation may not be adequate to prevent hemorrhage from causing irreversible harm. Such harm may be avoided if more expeditious hemostasis is achieved.
In aneurysm surgery, preventive measures may be taken to reduce the risk of serious hemorrhage. For example, a surgeon may employ temporary surgical clips which are applied to vessels which feed the aneurysm. The clips occlude blood flow to the aneurysm while the aneurysm repair is being performed and thereby reduce the risk of severe hemorrhage during the high-risk repair procedure. The clips are removed when the repair is completed.
Endoscopic procedures rely on a transparent view of the surgical field. When bleeding occurs, it obscures the surgeon's view and may make it impossible to continue the procedure, especially if the previously transparent fluid environment within which the tip of the endoscope is navigated is clouded by blood products.
The present invention is an improved method and device for modulating flow in biological conduits. The specific application which will be described is vascular occlusion for intracranial aneurysm surgery. Briefly, the prior art entails placing a pinch-valve-type clip around a vessel to reversibly occlude flow within it. The clip is often applied using a separate instrument, called a clip applier, which reversibly and controllably grasps the clip so that the surgeon may place the clip on a vessel, actuate (i.e., “close”) the clip, and then release the clip from the applier. The surgeon may use the same clip applier to engage an already-applied clip, de-actuate (i.e., “open”) the clip, and then remove it from the surgical field.
Existing vascular clips are designed to be safe, effective, and to provide a relatively unobstructed view of the operative field. They are usually made of a biocompatible, non-ferromagnetic material, such as one of the stainless steels (i.e., a chromium-containing alloy), titanium, or plastic. This disclosure pertains to any clip which has the following elements:
(1) a resilient element responsible for self-closing of the clip, such as a coil spring or a leaf spring; and
(2) two opposing jaw members (also known as “blades”) which provide the active surfaces between which a vessel may be pinched to limit or occlude flow.
Some additional embodiments also rely on the presence of two opposing arm elements located proximally on the clip which permit one to open the clip by approximating these elements using, for example, a clip applier.
Further embodiments of the invention are possible by modifying a certain category of clips, known as alpha clips, which, in addition to the aforementioned elements also contain a “crossover region” where crossing elements, referred to as the “crossovers,” change their relative positions depending on the degree to which the clip is open.
Besides alpha clips, the most commonly-used clips are pivot clips and mobile-fulcrum clips [illustrated on page 460 of the article by Dujovny et al., entitled “
Temporary microvascular clips
,” and found in the journal Neurosurgery, Volume 5 (1979)]. Briefly, these three categories of clips are distinguished as follows:
(1) alpha clips resemble the Greek letter “alpha” and contain a proximal helical spiral or leaf spring on each end of which emerges an arm; the arms have extensions, known as “crossovers”, which cross over one another en route to their corresponding jaws; the fulcrum of this clip lies proximally and is fixed in location; such a clip is shown in
FIGS. 0A
,
0
B, and
0
C;
(2) pivot clips, in contrast to the alpha clips, have a fulcrum point in between the arms and the jaws; an example of such a configuration is seen in an ordinary clothespin;
(3) mobile-fulcrum clips have a moveable fulcrum point the position of which depends on the magnitude of the gap between the jaws.
While the present disclosure is described using alpha clips as an example, the first and sixth embodiments set forth below may be applied to pivot clips and mobile-fulcrum clips (the sixth embodiment requires the presence of “arms” as defined above).
The descriptions provided herein allow one reasonably skilled in the materials and mechanical arts to modify an existing vascular clip to create an embodiment of the invention. Of course, one may de novo construct a clip by combining the designs of a present clip with the modifications of the present invention specified herein. The generic elements, named “main spring,” “arm,” and “jaw” refer to the corresponding elements in any alpha clip, pivot clip, or mobile-fulcrum clip. In addition, the element “crossover” refers to the element between an arm and its corresponding jaw in any alpha clip.
Construction of the invention from an existing clip involves:
(1) removal of parts of existing components of the clip, e.g., by drilling or machining;
(2) creating new components of the clip which, unless otherwise specified, can be made of the same material used for the clip;
(3) attaching new components to the clip or its modification, such as simple insertion in the case of inserting a hinge into its sockets, or such as welding as in the case of affixing a leaf spring to an arm.
There is an abundance of types, sizes, and shapes of vascular clips, and it should be noted that the present invention may be applied to any of these. It should also be noted that for the present state of art, a surgeon may have a general idea of the clip to be used in a particular situation, but often will not know a priori which particular clip to use; the surgeon may rely to some degree on trial-and-error to find the perfect match for a particular patient's anatomy and physiology at a given point in time during the surgical procedure.
The following published articles are of value in understanding the present state of art:
(1) J L D Atkinson, R E Anderson, and D G Piepgras (1990). A comparative study in opening and closing pressures of cerebral aneurysm clips. Neurosurgery 26: 80-85.
(2) M Dujovny, N Kossovsky, R Kossowsky, A Perlin, R Segal, F G Diaz, and J I Ausman (1984). Intracranial clips: An examination of the devices used for aneurysm surgery. Neurosurgery 14: 257-267.
(3) R Kossowsky, M Dujovny, and N Kossovsky (1981). Mettalurgical evaluation of the compatibility of surgical clips with their appliers. Acta Neurochirurgica 59: 95-109.
(4) M Dujovny, N Kossovsky, R K Laha, L Leff, N Wackenhut, and A Perlin (1979). Temporary microvascular clips. Neurosurgery 5: 456-463.
(5) L H Fink, R E Flandry, R A Pratt, and C B Early (1979). A comparative study of performance characteristics of cerebral aneurysm clips. Surgical Neurology 11: 179-186.
Several earlier patents have addressed the need to controllably occlude blood vessels. For example, a device for remote occlusion of a blood vess
Law offices of Royal W. Craig
Thaler Michael H.
Trinh (Vikki) Hoa B.
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