A deformable aerodynamic profiled member has a front profile area and a rear profile area in the outflow area. It is bounded by shells on the pressure side and/or on the suction side, converging in a rear profile edge (6). D33 piezo actuators are provided in at least some locations for deformation of the profiled member. The piezo actuators are aligned such that their length changes essentially in the direction of the planes of the shells when acted upon by electricity.

This application claims the priority of German patent document 103 04 530.9, filed Feb. 4, 2003 (PCT International Application No. PCT/DE2004/000162, filed Feb. 3, 2004) the disclosure of which is expressly incorporated by reference herein.
The present invention relates a deformable aerodynamic profile member.
Various arrangements and methods are known for adjusting and optimizing the buoyancy and flow resistance of a body with flow around it (e.g., in the form of an aerodynamic profile), to adapt to various ambient conditions. Such aerodynamic profiles may include, for example, helicopter rotor blades, aircraft wings or turbine blades, to name but a few examples.
In the field of aeronautical engineering, deformation of a profile curvature of such aerodynamic profiled members has been achieved mechanically by using different adjustment devices. However, gaps and hollow spaces then usually occur in the shell of the profile, which is a disadvantage for many applications.
To counteract this problem, German patent document DE 196 43 222 C2 discloses an arrangement in which the properties of flow around a body are modified by continuous deformation of an aerodynamic profile having an elastically deformable shell, using an adjustment device integrated into the profile.
German patent document DE 197 09 917 C1, on the other hand, describes a device for controlled deformation of a shell structure, having a number of bulging ribs, which are joined together by actuators to achieve a change in the curvature of an elastic component connected to the bulging ribs.
In addition, composite structures for producing and detecting deformation are known which have a plurality of piezoelectric fibers running in parallel (for example, U.S. Pat. Nos. 5,869,189 and 6,048,622). However, such fibers are very expensive, and are relatively inefficient due to their great weight. Furthermore, suitable contacting of the piezoelectric fibers is necessary. Another factor to be taken into account is achieving the most homogeneous possible field distribution, which is necessary for producing the piezoelectric effect. The electrodes required for this purpose may be provided, for example, by separate layers (i.e., electrode layers), which can be integrated into the composite structure only with a corresponding extra technical expense.
When using this known composite structure to induce deformation, it is also a disadvantage that as a rule a high voltage is necessary to trigger the piezoelectric fibers. This means that a high energy demand is generated, which makes the arrangement inefficient, and that a complex electronic control system is necessary. In addition, suitable safety provisions must be taken.
It is thus an object of the present invention to create a deformable aerodynamic profile whose profile curvature can be varied in a technically simple and effective manner.
This and other objects and advantages are achieved by the aerodynamic profiled member according to the invention, which has a front profile area, and a rear profile area situated in the downflow. The profiled member is bounded by shells on a pressure side and on a suction side, which converge at a rear edge of the profile. According to the invention, the profiled member is equipped with d33 piezo actuators in at least some locations for its deformation, such that their change in length occurs essentially in the direction of the planes of the shells when acted upon by electricity.
Because the so-called longitudinal (d33) effect (in which the change in length of the piezoelectric material takes place in the direction of the electric field) is known to be greater than the usual (d31) piezo effect (in which the change in length is perpendicular to the electric field), a more effective introduction of forces into the aerodynamic profile is possible by an appropriate alignment of piezoelectric actuators.
It is especially expedient to arrange the d33 piezo actuators on the pressure side and/or suction side of the shell. The shells are usually made of conventional construction materials and the d33 piezo actuators are attached, for example, by adhesive bonding. However, mechanical fastening means such as clamping devices or screwing devices may also be used for this purpose. In addition, the shell provided with the piezo actuators may also be provided with a protective layer to protect the piezo actuators from impact, pressure, pulling or other external influences (including environmental factors).
According to another embodiment, the d33 piezo actuators are integrated into the shell on the pressure side and/or suction side. This configuration is preferred in so-called composite structures, which may be metallic, but may also be so-called MMCs (metal matrix composites). Likewise, the d33 piezo actuators may be integrated into composite fiber structures. One advantage of this arrangement is that the piezo actuators are automatically protected.
Similarly, the invention may also be applied to other floating bodies, which are attached with an articulated joint to the aerodynamic profile, such as control flaps. In this case the control flap is provided with d33 piezo actuators which are aligned so that their change in length takes place essentially in the plane of the flap when exposed to an electric current in a similar manner. A design in which the flap with d33 piezo actuators is connected to the rear profile edge of the aerodynamic profile with an articulated connection is particularly advantageous.
It is especially advantageous for the d33 piezo actuators to be used in the form of stacks of piezoelectric elements (so-called piezo stacks or "laminar" piezo actuators) which have a laminar structure with alternating electrode layers and layers of piezoelectric material. This arrangement has the advantage that the electrodes are integrated into the piezo actuator, which greatly facilitates contacting of the piezo actuator and at the same time ensures a homogeneous field distribution within the piezo actuator. It is especially expedient that the electric field for inducing the d33 effect is supplied via the electrodes integrated into the laminar piezo actuator. The invention can therefore be implemented especially effectively and in a technically simple manner.
Furthermore, it is expedient for the laminar d33 piezo actuators to have a low thickness (approx. 0.5 to 2.5 mm) so that they have hardly any influence at all on the flow conditions. It is advantageous that such thin-layered d33 piezo actuators can be introduced or integrated easily into the shells of aerodynamic profiles, and have a low weight.
Furthermore it is expedient that the side dimensions of the d33 piezo actuators are between 5 and 60 mm. This permits easy adaptation to given geometries (e.g., corners, edges, rounded shapes, etc.).
The invention can be used, for example, in helicopter rotor blades, aircraft wings, turbine blades or the like.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.


A method and apparatus for correcting for the temperature sensitivity of pressure sensitive paint using two layers of paint: one that is sensitive to both pressure and temperature and one that is sensitive to only temperature changes. A temperature sensitive paint layer or film is placed on a model to be tested in a wind tunnel for pressure changes over the surface of the model. The first film is responsive to temperature changes and has a magnitude of luminosity depending upon the temperature of the ambient air. Placed over the temperature film is a pressure sensitive paint or film that is sensitive primarily to pressure changes, but also to temperature changes, and produces a magnitude of luminosity depending upon the change in both temperature and pressure. The pressure paint layer is transparent to the luminescence of the temperature layer and a measurement of the luminosity of the temperature layer and the pressure layer is taken. The pressure layer luminosity is corrected for the temperature layer luminosity, thereby enabling a true pressure reading to be determined by comparing the magnitude of luminescence of both the temperature layer and the pressure layer.

The present invention relates to pressure sensitive paints, and more particularly to a method and apparatus of correcting for the temperature sensitivity of pressure sensitive paints.
Many vehicles, such as automobiles and aircraft, have to operate in an atmosphere of dense gas. Therefore, it is highly desirable to optimize the aerodynamics of these vehicles. Furthermore, with certain vehicles such as aircraft, certain aerodynamic interactions must be known to assure that the aircraft will perform properly and be capable of being flown in a controlled manner. To this end, several methods have been used to measure pressure on the surface of models of different vehicles to assure that they will be able to operate efficiently and properly during travel. Wind tunnels are often used to simulate a vehicle traveling at a particular speed through the atmosphere. Once the model is placed in the wind tunnel, air is moved at a particular speed over the model to test how the model reacts to the wind speed. One particular measurement is the pressure produced over the various surfaces of the model during the tests in the wind tunnel. To measure these different pressure points, many techniques have been developed.
Generally, wind tunnels use several mechanical devices to measure the pressure changes along the surfaces of the models placed in the wind tunnel. Each of these numerous mechanical devices are affixed to different electrical leads, which electrical leads are coupled to a computer to produce a representation of the pressure changes produced on the model by the wind in the wind tunnel. These systems are often cumbersome, time consuming, and hard to set up and take down for each model being tested.
Other methods of detecting pressure changes include pressure sensitive paints (PSP). These PSPs are able to luminesce at a particular wavelength when pressure is applied thereto. Generally, PSPs luminesce when a particular type of light energy is applied to them at a particular wavelength. Also, the PSPs are oxygen permeable. In the wind tunnel, the PSP, being oxygen permeable, receives a particular amount of oxygen depending upon the pressure being applied to an area. When a particular wavelength of light is applied to the PSP, it luminesces. If oxygen is in the matrix of the PSP, the oxygen absorbs a certain amount of the luminescent energy that would otherwise be emitted, thereby changing the luminescence of the PSP depending upon the amount of oxygen that is absorbed into the PSP layer. Therefore, a pressure of oxygen is determined and interpreted therefrom. A general pressure of the air around the particular area of the model being measured is determined from the known concentration of oxygen. Often the PSPs are sensitive not only to pressure, but also temperature. Therefore, temperature can effect the degree of luminescence from the PSP. Due to this temperature sensitivity, pressure cannot be accurately determined from the luminescence of the PSP alone.
Several methods have been attempted to correct for the temperature sensitivity of PSPs with only marginal success. One method is to simply shorten the amount of time between when measurements are taken. That is, the time between a zero or initial reference, that being when no wind or pressure is being applied to the model, and when the maximum amount of wind pressure is being applied to the model. However, this does not actually correct for temperature, but rather simply reduces the amount of temperature change that occurs and reduces the error of the PSP to one that is acceptable for the tests.
Other methods have attempted to mix several different sensors into a single film wherein each is affected by temperature, pressure, or other factors. The mixing of all of the phosphorescence species into a singular film, however, has reduced the temperature error of the PSP only marginally. Furthermore, it is difficult to provide each of the particular phosphorescent species in a singular film since it increases the effort and cost necessary to produce such a film.
Additionally, attempting to correct for the temperature change through data conversion after the test data has been taken during a test has been tried. Again, this method is long and arduous and only corrects for a certain amount of the temperature related error. Additionally, this method is only marginally helpful in correcting for the temperature change in the PSPs.
The present invention relates to a system that can adjust or take account of the temperature sensitivity of a pressure sensitive paint to produce a measurement that is nearly error free due to temperature sensitivity of the pressure sensitive paint.
A first preferred embodiment of the present invention includes a system for detecting at least two physical characteristics near a surface being tested. A first luminescent film, capable of emitting light having a wavelength in a first discrete range, is placed on the surface. A second luminescent film, capable of emitting light having a second wavelength in a second discrete range, is placed over the first film. A radiation source which emits radiation able to excite the first luminescent film and the second luminescent film is focused on the films. An analysis system detects the brightness of the light emitted by the first luminescent film and the brightness of the light emitted by the second luminescent film. The first luminescent film and the second luminescent film are placed on the surface substantially coplanar and the first luminescent film is substantially transparent to the light emitted from the second luminescent film.
A second preferred embodiment of the present invention comprises a method of more accurately determining a pressure on a surface being tested. The method comprises measuring the brightness of light emitted by a first film sensitive to temperature, which covers the surface being tested. Additionally, the brightness of light emitted by a second film, which is sensitive to both pressure change and temperature, and which covers the first film, is measured. At least a first measurement of the brightness of light emitted by each of the films is taken. Then the surface is made to experience a pressure and temperature change. At least a second measurement of the brightness of light emitted by each of the films is taken. Finally, an accurate determination of the pressure experienced by the surface is obtained by comparing the first measurements and the second measurements.
A third preferred embodiment of the present invention includes a system to determine the pressure over an area of a surface. A member under test has a first film applied so as to surround the member, wherein the first film comprises a sensor that is adapted to emit light at a first wavelength. A second film is placed over the first film to surround the first film. The second film comprises a second sensor adapted to emit light at a second wavelength. The first film is transparent to the second wavelength. A test is performed and each sensor in each film emits light at a particular brightness which is measured.

Method and apparatus to correct for the temperature sensitivity of pressure sensitive paint


The invention relates to the manufacture of metal foil electrodes useful in the manufacture of printed circuit boards having passive circuit components such as capacitors, resistors or inductors configured in a planar orientation. A copper foil is coated on each opposite side with a thin layer of nickel, which increases the range of functionality of the foil.

1. Field of the Invention
The invention relates to the production of passive circuit devices such as resistors, capacitors and inductors that can be embedded in printed circuit boards (PCB""s). Such may be formed using an electrically conductive substrate comprising a copper foil having a thin layer of nickel on both sides of the copper foil as the primary electrode.
2. Description of the Related Art
Printed circuit boards are well known in the field of electronics, and are used for a wide variety of commercial and consumer electronic applications. They are useful for large scale applications, such as in missiles and industrial control equipment, as well as in small scale devices. For example, they can be found inside radio and television sets, telephone systems, automobile dashboards and computers. They also play an important role in the operation of airborne avionics and guidance systems. The surface area on printed circuit boards for the mounting of components is becoming a limiting form factor as the need for function and speed increases. Currently, 40+% of the surface area of conventional PCB""s is occupied by passive devices, such as resistors, capacitors and inductors. Through the redesign of these devices into a planar configuration, they can be embedded in the body of the printed circuit board thereby increasing available surface area for active devices.
It is known in the art to produce printed circuit boards having integrated resistors, capacitors and magnetic components such as inductors and transducers. There are various available technologies that partially address the technological requirements for the fabrication of passive devices, but each has a its drawbacks. This invention enables the fabrication of planar passive devices that may be embedded in the body of a printed circuit board. Further, the nickel layer allows for the fabrication of devices with wider performance spectra thereby increasing scope of application. Additionally, nickel whether as a pure metal or in alloy form is known to increase foil adhesion to resins commonly used in the construction of printed circuit boards, has an affinity for ceramics and metal oxides and has added benefits of increasing thermal stability and resistance to chemical corrosion. The invention provides foil planes that can be separated by a dielectric medium and can be configured to act as a capacitor. The foil can also be coated with resistive or inductive material in order to perform these functions. Improved adhesion to these materials and enhanced thermal stability are important features of the invention. Processes for imaging and generating clearance holes and other circuit features using photoresists and chemical etching techniques are well known. The passive elements may then be embedded into the printed circuit board of an integrated circuit package by standard lamination techniques.
The invention provides an electrically conductive substrate comprising a copper foil having opposite surfaces, wherein one or both of the opposite surfaces have optionally been subjected to a electrochemical polishing treatment, a mechanical polishing treatment or a roughening treatment; and a layer of nickel each of the opposite surfaces.
The invention also provides a process for producing an electrically conductive substrate comprising forming a copper foil having opposite surfaces; optionally subjecting one or both of the opposite surfaces to a electrochemical polishing treatment, a mechanical polishing treatment or a roughening treatment; and depositing a layer of nickel onto each of the opposite surfaces.
An electrically conductive substrate is provided comprising a copper foil having opposite surfaces, wherein one or both of the opposite surfaces have optionally been subjected to a electrochemical polishing treatment, a mechanical polishing treatment, or a roughening treatment; and a layer of nickel each of the opposite surfaces.
The first step in the process of the invention is to produce a metal foil, preferably copper, by either electroplating onto a rotating drum or by rolling a copper ingot with subsequent annealing. According to the invention, the term xe2x80x9ccopper foilxe2x80x9d includes copper or copper alloys, and may include copper foils containing zinc, brass, chrome, nickel, aluminum, stainless steel, iron, gold, silver, titanium and combinations and alloys thereof. The thickness of the copper foil may vary according to each particular application. In a preferred embodiment, the copper foil has a thickness of from about 5 xcexcm to about 50 xcexcm. It is well know to produce copper foils by electrodeposition processes. One preferred process includes electrodepositing copper from a solution of a copper salt onto a rotating metal drum. The side of the foil next to the drum is typically the smooth or shiny side, while the other side has a relatively rough surface, also known as the matte side. This drum is usually made of stainless steel or titanium which acts as a cathode and receives the copper as it is deposited from solution. An anode is generally constructed from a lead alloy. A cell voltage of about 5 to 10 volts is typically applied between the anode and the cathode to cause the copper to be deposited, while oxygen is evolved at the anode. This copper foil is then removed from the drum. Electroplated foil is available from Oak-Mitsui of Hoosick Falls, N.Y. Rolled copper is available from Olin Brass of East Alton, Ill.
The surfaces of the foil can be modified to enhance the performance of the embedded passive device. If a rougher surface is required to assist in adhesion of the embedded passive material to the foil or the subsequent adhesion of the printed circuit substrate to the foil, the foil may be pre-treated with a bond enhancing treatment known in the art, which may serve as an adhesion promoter for the foil. In this regard, a treatment of either nickel or copper nodules can be applied to either or both sides of the foil. One roughening technique such as by electrolytically depositing micro-nodules of a metal or alloy such as copper or nickel and increase adhesion to the foil. Such may be conducted according to U.S. Pat. Nos. 6,117,300; 5,679,230 or 3,857,681 which are incorporated herein by reference. The nodules may range in size from about 40 microinches to about 200 microinches, or more preferably from about 40 microinches to about 150 microinches.
The surface microstructure of the foil is measured by a profilometer, such as a Perthometer model M4P or S5P which is commercially available from Mahr Feinpruef Corporation of Cincinnati, Ohio. Topography measurements of the surface grain structure of peaks and valleys are made according to industry standard IPC-TM-650 Section 2.2.17 of the Institute for Interconnecting and Packaging Circuits of 2115 Sanders Road, Northbrook, Ill. 60062. In the measurement procedure, a measurement length Im over the sample surface is selected. Rz defined as the average maximum peak to valley height of five consecutive sampling lengths within the measurement length Im (where Io is Im/5). Rt is the maximum roughness depth and is the greatest perpendicular distance between the highest peak and the lowest valley within the measurement length Im. Rp is the maximum leveling depth and is the height of the highest peak within the measuring length Im. Ra, or average roughness, is defined as the arithmetic average value of all absolute distances of the roughness profile from the center line within the measuring length Im. The parameters of importance for this invention are Rz and Ra. The surface treatments carried out produce a surface structure having peaks and valleys, which produce roughness parameters wherein Ra ranges from about 1 to about 10 xcexcm and Rz ranges from about 2 to about 10 xcexcm.
In another embodiment of the invention, a smooth copper surface may be required. For example, capacitors require the dielectric spacing to be minimized. In order to prevent shorting of the electrodes, it is desired that the surface be as smooth and free of defects as possible. Techniques to accomplish this are electrochemical or mechanical polishing. A smooth surface may also be required for resistors to help insure uniformity. Mechanical polishing may be conducted according to the techniques described in U.S. Pat. Nos. 5,688,159 or 6,291,081 which are incorporated herein by reference. Electrochemical polishing may be conducted by submersing the foil in a copper pyrophosphate bath. A current is applied in such as way as to make the foil anodic. A suitable current ranges from about 0.2 amps/cm2 to about 2 amps/cm2 for from about 10 seconds to about 1 minute. The copper will effectively de-plate on the peaked areas of the foil and become more smooth.
A layer of nickel is applied onto both side of the copper foil to thereby form an electrically conductive structure. The nickel layer preferably includes nickel or a nickel alloy, comprising other metals such as zinc, brass, chrome, aluminum, stainless steel, iron, gold, silver, titanium, and combinations and alloys thereof. The nickel layer may be applied to the copper foil by any conventional method such as by electrodeposition, electroplating, sputtering or electroless plating. In a preferred embodiment, the nickel layer is deposited by electrodeposition. The thickness of the nickel layer may vary according to each particular application. In a preferred embodiment, the nickel layer has a thickness of from about 0.1 xcexcm to about 5 xcexcm, preferably from about 0.2 xcexcm to about 2 xcexcm, and most preferably from about 0.4xcexc to about 0.6xcexc. This can be accomplished using Watt""s nickel, an aqueous solution of nickel sulfamate, nickel chloride and boric acid or other commonly known plating solutions in conjunction with a soluble nickel anode. Plating times and current density will vary with chemistry and desired deposition thickness.
The inventive electrically conductive substrate comprising a copper foil applied on each side by a nickel layer is useful for the fabrication of electrodes and passive electronic devices. Such planar passive devices are to be embedded in printed circuit boards or integrated chip packaging. These devices are produced by applying a suitable additional layer onto the nickel. The nature of the additional layer depends on whether a capacitor, resistor or inductor device is to be produced.
In order to form one of the aforementioned passive devices, after the thin nickel layer of appropriate thickness has been deposited on the copper foil surface, an additional layer may be applied to one or both nickel layers. The composition of this layer will determine the function, i.e. capacitor, resistor or inductor. Suitable additional layers may be composed of a metal, a polymer, a ceramic or combinations thereof on one or both of the nickel layers. One preferred material suitable for forming inductors is NiFe. Materials suitable for forming capacitors non-exclusively include thermoplastic polymers and thermosetting polymers such as epoxies, polyimides, Teflon, and polyesters. A pair of polymer coated sheets are attached together forming a sandwich of two sheets of nickel coated copper and the dielectric polymer material therebetween. Resistive elements can be produced by forming a layer of nickel phosphorous alloys as described in U.S. Pat. No. 3,808,576. Electrically resistive layers may be formed by forming a uniformly dispersed layer of an electrically resistive composite material comprising a conductive material and a non-conductive material. Such may be formed by well known electrodeposition processes using an electroplating solution including solid non-conductive particles and a conductive metal ion that forms a conductive metal upon electroplating. The conductive metal used in the resistive material and/or in the conductive metal layer of the layer foil material of this invention may be any metal, metalloid, alloy, or combination thereof that is able to conduct an electrical current. Examples of conductive metals that are useful as the conductive metal or alloy in the resistive co-deposit material include one or more of the following: antimony (Sb), arsenic (As), bismuth (Bi), cobalt (Ce), tungsten (W), manganese (Mn), lead (Pb), chromium (Cr), zinc (Zn), palladium (Pd), phosphorus (P), sulfur (S), carbon (C), tantalum (Ta), aluminum (Al), iron (Fe) titanium (Ti), chromium, platinum (Pt), tin (Sn), nickel (Ni), silver (Au), and copper (Cu). The conductive metals and alloys may also be chosen from alloys of one or more of the above-identified conductive materials or a plurality of layers of one or more of the above-identified conductive metals or alloys. Non-conductive materials in the resistive composite materials may be any non-conductive material that can be combined with a conductive metal to give a useful co-deposited electroplated resistive foil layer. It is preferred that the non-conductive material is a particulate material that can be evenly dispersed throughout the resistive foil material. Such particulate materials include but are not limited to metal oxides, metal nitrides, ceramics, and other particulate non-conductive materials. It is more preferred that the particulate non-conductive materials are selected from boron nitride, silicon carbide, alumina, silica, platinum oxide, tantalum nitride, talc, polyethylene tetra-fluoroethylene (PTFE), epoxy powders, and mixtures thereof. The additional layer may be applied by using any suitable technique non-exclusively including sputtering, chemical vapor deposition, combustion chemical vapor deposition, electrodeposition such as electrochemical deposition (plating), electroless plating, sol-gel process, coating such as roll coating, screen printing, dispensing, lamination and spraying. Preferably the additional layer has a thickness of from about 0.01 to about 25 microns.
The fabrication of electrodes would involve the steps of:
a) producing a copper foil by electrodepositing copper from a solution of a copper salt onto a rotating metal drum, or by rolling a copper ingot with subsequent annealing;
b) optionally treating one or both sides of the foil with a mechanical polishing treatment or a roughening treatment such as a bond enhancing layer of nodules;
c) optionally modifying one or both sides of the foil by electrochemical or mechanical polishing to improve its surface smoothness;
d) coating a layer of nickel on one or both sides of the copper foil;
e) applying an embedded passive material suitable for forming a resistor, capacitor or inductor, onto either side of the nickel coated copper foil;
f) drying, curing or annealing the embedded passive material as needed;
g) applying an electrode to the device if required.
The following non-limiting examples serve to illustrate the invention. It will be appreciated that variations in proportions and alternatives in elements of the components of the invention will be apparent to those skilled in the art and are within the scope of the present invention.

Nickel coated copper as electrodes for embedded passive devices


An intravascular catheter system for the treatment of occluded blood vessels that includes tissue displacement or hinged expansion members that are movable from a closed to an open position. An actuating assembly may be provided for moving the tissue expansion members between an open and closed position to exert a substantially lateral distal end force upon the region surrounding an occluded blood vessel. The tissue expansion members may stretch apart, tear or otherwise disrupt a vascular occlusion sufficiently to create a pathway that may support the passage or placement of a guidewire or an interventional vascular device across the occlusion or obstruction. Methods of crossing or displacing a vascular occlusion are further provided that include the positioning of a vascular catheter having at least one hinged spreading member positioned at the distal region of the catheter that is responsive to directed force along the longitudinal axis of the catheter. A directed force is applied to the actuator in order to deploy the spreading member and displace a vascular occlusion creating a path to permit the passage of a guidewire or device therethrough.

The invention is generally directed to medical devices and catheters designed for the treatment vascular occlusions. More particularly, the invention is directed to cardiovascular catheters having the ability to sufficiently fracture, disrupt or displace a vascular occlusion in order to allow a guidewire to pass through the occlusion within the lumen of a blood vessel. The invention is further directed to a vascular catheter for crossing a substantially occluded blood vessel by disrupting the occlusion to provide a pathway that permits the passage of a guidewire or interventional cardiovascular device such as a stent or other catheter apparatus.
Medical science has long sought effective treatments for disease states that cause stenosis (narrowing or obstruction) of the lumen (interior passage of the artery) of an artery. This condition, known generally as a vascular occlusion, is found in patients suffering from the disease of atherosclerosis (an accumulation of fibrous, fatty or calcified tissue in the arteries). Symptoms of arterial occlusion include hypertension (high blood pressure), ischemia (deficiency of circulation), angina (chest pain), myocardial infarction (heart attack), stroke, or death. An occlusion may be partial or total, may be soft and pliable or hard and calcified, and may be found at a great variety of sites in the arterial system including the aorta, coronary and peripheral arteries.
Of particular interest to cardiac medicine are the often disabling or fatal occlusions occurring in the coronary arteries (arteries supplying the heart). Traditionally, coronary artery occlusions have been treated by performing coronary bypass surgery. This is a procedure in which a segment of the patient""s saphenous vein may be taken from the patient""s leg and is grafted onto the affected artery at points proximal (upstream) and distal (downstream) to the occluded segment. While the procedure can improve the patients quality of life through reduced ischemia and angina, it is major surgical procedures with significant morbidity and mortality risks and a long convalesce period. Consequently, it is contraindicated for a significant portion of the patient population due to age and other factors. Moreover, in a significant percentage of patients, the saphenous vein graft may become occluded over the passage of time due to same disease processes which caused the original occlusion. If the patient has another saphenous vein, a second bypass procedure may be performed, once again incurring the risk, cost and prolonged hospitalization of this procedure. In fact up to 25% of bypass patients may require repeat surgery.
Newer, minimally invasive procedures are now preferred in the treatment of arterial occlusions. These procedures often include the use of long, thin, and highly flexible devices known in the art as catheters. During the procedure, the catheter is introduced into a major artery through a small arterial puncture made in the groin, upper arm, or neck, and is advanced and steered into the site of the stenosis. At the distal end of the catheter, various devices have been developed for operating upon the stenosed artery. For example, the more popular minimally invasive procedures include percutaneous transluminal coronary angioplasty (PTCA), directional coronary atherectomy (DCA), and stenting. PTCA employs a balloon to mechanically dilate the stenosis. In PTCA, a steerable guidewire is introduced and advanced under fluoroscopic observation into the narrowed artery and past the area of stenosis (e.g. blockage). Next, a balloon-tipped catheter is advanced over the guidewire until it is positioned across the stenosed segment. The balloon is then inflated, separating, fracturing or otherwise deforming the atheroma so as to enlarge the narrowed lumen of the artery sufficiently to increase blood flow to a previously ischemic or near ischemic section of the myocardium. Directional coronary atherectomy is another minimally invasive procedure that has been developed, a catheter containing a cutter housed in its distal end is advanced over the guidewire into the stenosed segment. The housing is urged against the atheroma by the inflation of a balloon, so that part of the atheroma intrudes through a window in the side of the housing. Under fluoroscopic observation, the cutter is used to shave away the atheroma. The shavings are collected in the nosecone of the housing and withdrawn along with the catheter. Similarly, stenting is another current procedure in which a wire framework, known as a stent, is compressed and delivered a balloon catheter. The stent is positioned across the stenosed segment of the artery. The balloon is inflated, dilating the stent and forcing the stent against the artery wall. The hoped-for outcome is that the stent will hold the arterial lumen open for a prolonged period. Frequently, a stent is placed in an artery immediately following PTCA or DCA. The catheters selected for many of the aforementioned procedures are known as xe2x80x9cover-the-wire catheters.xe2x80x9d These catheters depend upon the positioning of a guidewire, which typically has a flexible portion at its distal end for steering. Over-the-wire catheters cannot be positioned adjacent the stenosis to carry out current procedures until the guidewire traverses or has been advanced across the stenosed arterial segment. Thus, where the occlusion is too severe to be crossed by a guidewire or where there is not enough room for the balloon, cutter, or stent delivery catheter, neither PTCA nor DCA nor stenting can be effectively performed.
Unfortunately, vascular occlusions often contain extremely hard, calcified tissue that forms an impenetrable barrier against the simple advancement of a guidewire across the occlusion. Even a less than total occlusion may contain complex structures which may trap or divert the steering end of the guidewire. Thus, the guidewire may not completely cross the occlusion, and may become diverted into the subintimal space between the atheroma and the arterial wall, or even become buried in the atheroma. In either case, the guidewire cannot be properly positioned across the stenosis to guide a balloon or cutting element. In such cases, bypass surgery may be necessary with the associated cost, risks, and recovery period. Thus, in patients suffering from severe or total arterial occlusion, it is preferable to do what has been difficult or impossible in the past, to open the severely or totally occluded artery itself, rather than by performing a bypass. If a guidewire and working catheter can be passed through or around the atheroma, the occlusion can be treated by a number of interventional procedures include PTCA, DCA, stenting, site-specific drug and radiation delivery or a combination of these different therapies.
Accordingly, it would be medically advantageous to circumvent a vascular occlusion. Appropriate devices and procedures for crossing the occlusion should be selected without perforating the blood vessel or artery being treated, an extremely serious and even life-threatening consequence. A physician will generally not use a system which would be unsafe, nor would patients want a physician to use such a system. Therefore, solutions to the problem of crossing a vascular occlusion such as an atheroma should be safe, and in many instances, include a system of guidance for the device to bypass such an occlusion. There has been a long felt need in the practice of interventional cardiology and radiology for a reliable guidance system for these types of vascular devices. As understood by those in the art, the device often travels through a complex, tortuous vascular anatomy before it even gets to the occlusion. Then the occlusion itself often has a irregularly shaped (e.g. eccentric) morphology. Attempting to cross such an occlusion without reliable imaging of the adjacent vasculature is dangerous. For example, it is easy to dissect the tissues of the arterial wall instead of the occlusion, thereby creating a false lumen and possibly perforating the artery. If enough blood from a perforated artery accumulates in the pericardial space surrounding the heart, it will result in a condition known as cardiac tamponade in which the heart is compressed and emergency surgical intervention is required to avert heart failure and death. Physicians have attempted to avoid such adverse events through the use of imaging systems/procedures such as biplane fluoroscopy. This is an imaging system that has been used in conjunction with coronary catheterization wherein the physician observes two flat real-time x-ray images acquired from different angles. However, biplane fluoroscopy may be unreliable, costly, and relatively slow. Delay is unacceptable in many instances, for it contributes to trauma and stress and creates opportunities for complications and failures of technique. While advanced medical imaging systems may be of diagnostic interest, they are not a substitute for effective interventional treatment for severe occlusive arterial disease. There persists a long felt need in the art for a vascular device which is capable of successfully crossing an arterial occlusion with a relatively low risk of perforating the artery. What is especially needed is a therapeutic working device which assists the physician in safely restoring normal blood flow rates within diseased blood vessels. What is further needed is a vascular catheter system that may allow effective treatment of a severely occluded artery and, in particular, a totally occluded artery.
The present invention provides methods and apparatus for the treatment of vascular occlusions. It is an object of the invention to disrupt vascular occlusions or other blockages formed within blood vessels in order to provide pathways for the placement of guidewires, interventional devices and catheters as part of an overall effort to restore normal circulatory function. It is advantageous to cross a vascular occlusion by finding and/or creating a path with the least or relatively low mechanical resistance through or around the occlusion. The invention further provides apparatus and methods to tear or to mechanically fracture a vascular occlusion, or to separate a vascular occlusion from a blood vessel wall, with minimal risk of perforating the adventitia of an arterial wall.
One aspect of the invention provides apparatus for treating a vascular occlusion. A catheter may be selected comprising an elongated shaft that is formed with at least one lumen extending from the proximal section to the distal section of the shaft. A hinged spreading member may be positioned at the relatively distal section of the shaft The spreading member may include a distal most end that moves in a substantially lateral direction away from the central axis of the shaft to disrupt a vascular occlusion. An actuating assembly may be also positioned along at least a portion of the elongated shaft to move or to direct the distal most end of the spreading member in response to an applied actuation force. The actuating assembly may further include a cam follower or other guiding region that is formed on a relatively interior portion of the hinged spreading member.
Another embodiment of the invention includes an intravascular catheter for expanding or stretching vascular tissue. The intravascular tissue expanding catheter may include a catheter shaft defined by a distal end having at least one conduit extending along the longitudinal axis of the catheter shaft. A housing may be formed at the distal end of the catheter shaft wherein the housing includes at least one hinged deflecting member defined by a distal most tip that moves in a substantially lateral direction away from the central axis of the shaft to expand tissue surrounding a vascular occlusion. An actuation assembly may be also positioned along the catheter shaft to move the distal most tip of the hinged deflecting member away from the central axis of the shaft. The catheter shaft may be also formed of braided material and a flexible inner coil shaft component that supports a column load.
It is a further object of the invention to provide a vascular catheter that is formed with a tissue expansion assembly for tearing or fracturing an occlusion within a blood vessel. The vascular catheter may comprise a catheter body formed with a distal section and at least one longitudinal conduit. At least one tissue expanding member may be connected to the distal section of the catheter body. The expanding member may include a relatively proximal portion and a relatively distal portion wherein the distal portion is configured to spread apart relative to the proximal portion of the expanding member. An actuation assembly may be positioned within the catheter body, and may be in communication with the proximal portion of the tissue expanding member to spread apart the distal portion of the expanding member. The distal section of the catheter may further include a relatively fixed extension. The relatively proximal portion of the tissue expanding member may be connected to the fixed extension with a hinge pin to permit the relatively distal portion of the tissue spreading member to move away from the fixed extension.
It is an additional object of this invention to provide flexible catheter shafts that support variable column loads. The shaft may comprise an outer catheter shaft defined by a longitudinal shaft lumen. An inner coiled body that is defined by a longitudinal coiled lumen may be positioned within the longitudinal shaft lumen for column load reinforcement of the outer shaft. A movable pulling element may be slidably positioned within the longitudinal coiled lumen for relative movement of the pulling element with respect to the inner coiled body. Another variation of the invention is to provide a catheter shaft with a reinforced outer catheter shaft. An outer shaft may be formed with a lumen that includes an inner shaft positioned within the outer shaft lumen. The inner shaft may further include an actuation lumen and at least one inner shaft lumen, and may be formed by extrusion. A column load reinforcement sleeve may be formed with a sleeve lumen that is positioned within the actuation lumen. In addition, an actuation wire may be slidably positioned within the sleeve lumen to provide relative movement of the wire within the sleeve. At least one inner shaft lumen may be also configured for placement of a guidewire. In yet another variation, a reinforced catheter body may be selected having a braid reinforced catheter shaft formed with a longitudinal catheter shaft lumen. An actuation conduit and a guidewire conduit may be separately formed within the longitudinal lumen of the catheter shaft. Additionally, a compression or wound coil that provides compression support may include a coil lumen and may be positioned within the actuation conduit for column load reinforcement of the actuation conduit. A pulling element may be positioned within the coil lumen for relatively slidable movement within the coil.
Another object of the invention is to provide an intravascular catheter for expanding tissue that includes a catheter body formed with an outer reinforced shaft coaxially formed about an inner coiled body for column load reinforcement of the catheter body. The inner coiled body may further include an actuation conduit leading to a relatively distal section of the catheter body. A tissue expanding member may be connected to the distal section of the catheter body. The interior surface of the tissue expanding member may include a cam follower. Additionally, the expanding member may be defined by a relatively proximal portion and a relatively distal portion so that the distal portion is configured to expand relative to the proximal portion of the expanding member. An actuation element may be selected and positioned within the actuation conduit formed in the inner coiled body. The actuation element may be formed as a wire or tube that supports actuation forces, and may further include a cam for communication with the interior cam follower of the tissue expanding member to expand the distal portion of the expanding member when actuated. The surface of the cam includes a variety of curved or non-linear configurations, and is preferably complementary to the shape of the corresponding cam follower.
Another aspect of the invention includes methods for disrupting and crossing a vascular occlusion. The vascular occlusion may be separated, fractured or displaced to provide a pathway across the obstruction in order to accommodate the placement of a guidewire or interventional device as part of an overall effort to restore normal circulatory function within the blood vessel.
It is an object of the invention to provide methods of displacing a vascular occlusion by initially selecting a vascular catheter that is formed with a spreading member positioned at the distal region of the catheter. The spreading member may be configured to spread or stretch apart an occlusion and/or vascular tissue, and may be activated or actuated in response to a directed force along the longitudinal axis of the catheter. An actuator assembly may be positioned along at least a portion of the catheter to transmit the directed force which may be applied linearly or rotationally, or by transmitting pressure relatively distally to an actuation balloon, from a remote or proximal portion of the catheter to the spreading member. The vascular catheter may be positioned adjacent to a substantial or total vascular occlusion within a selected blood vessel before applying a directed force to the actuator in order to deploy or to spread apart the spreading member. The occlusion may be displaced or disrupted based upon the different elastic properties between stretchable blood vessel walls and materials which form vascular occlusions. The vascular occlusion itself may be also fractured or otherwise disrupted to provide a passageway across the occlusion in order to accommodate the placement of a guidewire or interventional device such as a stent after removing the vascular catheter from the selected blood vessel. The spreading member may be spread apart to disrupt a vascular occlusion to create a path substantially through or around at least a portion of the occlusion. Additionally, the spreading member may stretch out the blood vessel wall creating a path substantially between the occlusion and the blood vessel wall. When the vascular occlusion is adhered to the wall of a selected blood vessel, the spreading member may be also expanded or spread apart to separate the layers of the blood vessel wall. The vascular catheter may be distally advanced through the vascular occlusion to pass through at least a portion of or entirely through the occlusion. Another variation of the invention includes the method of selecting a guidewire and passing the guidewire through a conduit formed in the vascular catheter. The guidewire may extend along to the length of the catheter and reach the site of an occlusion. Upon activation of at least one spreading member, the guidewire may be advanced through or around at least a portion of the occlusion.
Other various methods of crossing a substantially occluded blood vessel are provided herein in accordance with the concepts of the invention. An intravascular catheter may be selected that includes a distally mounted tissue expanding member defined by a relatively proximal portion and a relatively distal portion so that the distal portion is configured to expand relative to the proximal portion of the expanding member. In addition, an actuation assembly may be positioned within the intravascular catheter to transmit a spreading force in order to expand the distal portion of the expanding member. The tissue expanding member may be placed or positioned within a blood vessel in proximity to an occlusion, and subsequently activated to stretch the blood vessel wall and disrupt the occlusion to permit the passage therethrough. The tissue expanding member may be deactivated thereafter, and the intravascular catheter removed from the target blood vessel. A guidewire may be positioned within the passageway formed within or alongside the disrupted or displaced occlusion in order to facilitate the placement of a stent or other interventional device. The guidewire may also pass through at least a portion of the occlusion before the tissue expanding member is deactivated. The catheter may be similarly advanced through or across at least a portion of the occlusion upon disruption of the vascular obstruction.
In yet another variation of the invention, a method is provided for crossing a coronary vascular occlusion. This procedure may begin by selecting and advancing a guidewire within a blood vessel to a vascular occlusion. An intra-coronary guiding catheter may be advanced over the guidewire so that the distal end of the catheter is in proximity to the vascular occlusion. The guidewire may be thereafter removed from the blood vessel. An intravascular catheter may be selected for placement within the guiding catheter that includes a spreading member positioned that is responsive to directed force along its longitudinal axis. Additionally, an actuator assembly may be positioned along the intravascular catheter to transmit a directed force applied from the proximal portion of the catheter to the spreading member. The intravascular catheter may be advanced through the intra-coronary guiding catheter to position the spreading member of the intravascular catheter substantially adjacent to the vascular occlusion within the blood vessel. A directed force may be applied to the actuator assembly to spread apart the spreading member in order to displace the vascular occlusion. Another variation of this method may include the advancement of the intra-coronary guiding catheter past or across the occlusion before removing the intravascular catheter from the blood vessel. In addition, a guidewire may be advanced past or across the displaced vascular occlusion after removing the intravascular catheter and before removing the intra-coronary guiding catheter.
Other variations of the invention described herein include a vascular catheter formed with a blunt end assembly for tearing or fracturing an occlusion within a blood vessel. It is an additional object of this invention to provide such an assembly wherein the assembly includes a catheter having a distal end and a proximal end and wherein a working end member fits in an interchangeable manner to the distal end of the catheter and wherein the working end comprises a blunt end member in accordance with the invention. It is an additional object of this invention to provide such an assembly wherein the blunt end member has a first closed position and a second open position and may be repeatedly opened and closed for tearing/fracturing the occlusion within the lumen of the blood vessel. It is a further advantage of the invention to provide a tearing or fracturing force that is stably applicable to a severe or total arterial occlusion. A mechanical working element may be stably operable upon a severe or total arterial occlusion in a manner unlikely to perforate the adventitia or other layers of the arterial wall. In addition, the blunt end member assembly may comprise: a blunt end member connectable to the distal end of the catheter, the blunt end member sized and shaped for fitting within the blood vessel and for tearing and/or fracturing the occlusion, the blunt end member having a first position for allowing the blunt end member to be located at the occlusion and a second position for fracturing the occlusion; and an actuation member for moving the blunt end member between the first and second positions, whereby the blunt end member is connectable to the distal end of the catheter and the blunt end member is deliverable to the occlusion in the first position and is actuable to a second position for fracturing the occlusion.
In one embodiment of the invention, an over-the-wire vascular catheter is provided comprising a blunt end member disposed at the distal end thereof and a securing balloon disposed about the distal end zone of the catheter proximal to the blunt end member. The catheter and blunt end member may be sized and shaped so as to allow the blunt end member to be advanced into contact with an occlusion in an artery. The balloon may be disposed on the outer surface of the distal end zone of the catheter and is inflatable to secure the distal end of the catheter within the artery, and thus to maintain engagement or longitudinal registration of the blunt end member with the occlusion. A balloon inflation lumen may be provided in the catheter. The blunt end member may comprise four jaw sections flexibly attached to the distal end of the catheter, and may be arranged symmetrically about the longitudinal axis thereof. The catheter may comprise a retractable actuation shaft having a ball-shaped ferrule fixed to the distal end thereof between the jaw sections. To accommodate a guidewire, the actuation shaft may include a lumen and the ferrule includes a center opening. The jaw sections may have a first, closed position in which the catheter may be advanced to engage the jaws with the occlusion. When the actuation shaft is retracted, the ferrule or cam impinges upon the inner surfaces or cam followers of the jaw sections, urging them apart toward a second, open position to fracture the occlusion. The ferrule may be formed with a frusto-conical profile.
In another embodiment of the invention, each jaw section may include a rectangular distal end or a spade-shaped configuration. In the first, closed position, the jaw sections form a channel substantially confining the guidewire to the longitudinal axis of the blunt end member. It is an advantage of this embodiment that when the jaw sections are in the first, closed position, a guidewire may be advanced into a portion of the occlusion bounded by the points of contact with the distal ends of the jaw sections. In another embodiment of the invention, the jaw sections may be fabricated from an alloy comprising nickel and titanium. It is an advantage of this exemplary embodiment of the invention that the superelastic properties of the alloy facilitate closing of the jaw sections when the ferrule is deactivated or de-actuated by an actuation member.
In another exemplary embodiment of the invention, the actuation member includes an actuation cable disposed in the catheter. The proximal end of the cable is manipulable from the proximal end of the catheter and the distal end of the cable is attached to the ferrule. It is an advantage of this exemplary embodiment of the invention that the cable increases the tension capacity of the actuation member during retraction of the ferrule. A part of the lumen of the actuating member may include a friction reducing coating. It is an advantage of this embodiment of the invention that the catheter slide easily over the guidewire. In another embodiment of the invention, the mating surface defined by the impingement of the actuation member upon the blunt end member includes a friction reducing coating. It is an advantage of this exemplary embodiment of the invention that the actuation member encounters minimal frictional resistance while urging the jaw sections apart.
In another embodiment of the invention, the entire blunt end member may be fabricated from a single piece of material. It is an advantage of this exemplary embodiment of the invention that fabrication of the blunt end member does not require attachment or assembly of multiple parts.
Another embodiment of the invention provides a blunt end member that includes a rigid tubular reinforcing member slidably disposed about the actuation shaft inside the distal end zone of the catheter. A tubular support member is disposed on the outer surface of the distal end of the catheter. The distal end of the support member includes a spring member deformably supporting a plurality of jaw sections. The support member may be crimped onto the distal end zone of the catheter, securing the catheter onto the reinforcing member. It is an advantage of this embodiment of the invention that a simple yet secure attachment is formed between the catheter and the blunt end member.
These and other objects and advantages of the invention will become more apparent upon further consideration of the specification and drawings. For further-understanding of the objects and advantages of the invention, reference may be made to the following description in conjunction with some of the accompanying drawings in which similar components are identified with similar reference numerals.

Methods and apparatus for treating vascular occlusions


A tripot joint (10) includes a tripot housing (12) having three guide channels (24) receiving three corresponding trunnions (20) of a tripot spider (16). A ball assembly (28) is mounted on each of the trunnions (20) and received in the guide channels (24). The ball assembly includes an inner ball (30), and outer ball (40), and a complement of roller elements (52). The inner balls (30) are slidable axially on the roller elements (52) relative to the outer balls (40). Each ball assembly (28) includes at least one yieldable retainer (58) mounted on the outer ball (40) and projecting into the axial sliding path of the inner ball (30) in at least partial overlapping relation to the inner ball (30). The yieldable retainers secure the inner and outer balls (30, 40) against axial separation prior to joining the ball assemblies (28) with the trunnions (20) and guide channels (24). During operation of the joint (10), the yieldable retainers (58) are displaced out of the axial sliding path through normal axial forces exerted by the inner ball against the retainers (58), allowing for full functional axial sliding movement of the inner balls (30) relative to the outer balls (40) during transmission of torque through an angle of the joint (10).

This invention relates generally to tripot joints.
Typical tripot joints include a tripot housing that is fixed at one end to a shaft and open at its opposite end to receive a tripot spider into the housing which is fixed to another shaft. The spider has three trunnions which project radially outwardly into three respective longitudinal guide channels of the housing. Each trunnion carries a ball assembly which rollably guides the trunnions along the channels. This type of joint enables torque to be transmitted between the shafts at an angle and further enables a certain amount of axial plunging movement of the spider within the housing during operation of the joint to accommodate adjustment in the effective length of the shafts. A typical application for such joints is in front wheel drive applications for automotive vehicles, where the joint forms part of a shaft assembly operative to transmit torque from the transmission to the front drive wheels, while allowing for effective changes in the axial length of the shaft assembly through plunging of the tripot joint to accommodate up and down movements of the drive wheels.
The complex motion of such tripot joints make them susceptible to noise, shudder, and/or chattering. The shaft angle and rotation of the joint during the transmission of torque, coupled with axial plunging of the spider within the housing, presents a challenge to design such joints so that the ball assemblies to run true in the guide channels of the housing, attributing at least in part to the noise, chatter and/or shudder problems.
One particular type of tripot joint shown to perform exceptionally well is manufactured by the assignee of the present invention. It employs a multi-part ball assembly on each trunnion that includes an inner ball formed with a part-spherical inner concave surface that mates with a part-spherical convex surface of the respective trunnions and supports an outer roller or ball on a complement of needle rollers which support the outer ball for rotation relative to the inner ball, and enable the inner ball, and thus the trunnions, to shift or slide axially of the outer ball when transmitting torque through the joint at an angle in order to maintain the outer balls riding in their respective guide channels of the housing.
Typically, the outer ball has bearing retainers adjacent its axial ends which serve to capture the bearings in the axial direction. The retainers stop short of extending into the path of the inner ball in order that the inner ball is able to slide axially beyond the ends of the rollers. Thus, there is nothing retaining the inner ball against axial separation from the outer ball before the ball assemblies are mounted on the trunnions and disposed within the guide channels of the housing. As such, the ball assemblies are subject to inadvertent disassembly and must be carefully handled during the manufacture and service of the tripot joint or else the ball assembly can fall apart under its own weight. Once the inner ball is separated from the outer ball, the complement of needle rollers are prone to falling inwardly and becoming separated from the outer ball, further adding to the handling difficulties.
It is an object of the present invention to eliminate or greatly minimize the foregoing limitations of prior tripot joints while maintaining their high performance.
A tripot joint assembly constructed according to the present invention includes a tripot housing coupled to a first shaft and having three axially extending ball channels, and a tripot spider coupled to a second shaft and having three radially outwardly extending trunions which are disposed in the guide channels and each presenting a convexly curved outer surface. A ball assembly is disposed on each trunion and includes an inner ball having an inner concavely curved surface mating with the convexly curved surface of each trunion to establish a rotatable and angular support of each inner ball on its respective trunion. The ball assemblies each include an outer ball having a convexly curved outer surface rollably engaging the guide channels of the housing and an inner surface spaced radially from an outer surface of the inner ball. Each ball assembly further includes a complement of roller elements disposed between the inner and outer balls and providing rolling support of the outer balls on the inner balls, and axial sliding support of the inner balls on the outer balls. According to the invention, at least one yieldable retainer is mounted on each outer ball and projects radially inwardly into the axial sliding paths of the inner balls in at least partial overlapping relation to the inner balls. The retainers present yieldable impediments along the axial sliding paths that are operative to yield out of the axial sliding paths during operation of the joint in response to application of an axial sliding force on the retainers exceeding a pre-determined yield force of the retainers to permit axial movement of the inner balls along the outer balls beyond the retainers. The retainers are further operative to restrain the outer balls against axial separation from the inner balls prior to disposing the ball assemblies within the guide channels.
The invention has the advantage of simplifying the manufacture and assembly of tripot joint assemblies, particularly with respect to the ball assemblies.
The ball assemblies, fitted with the yieldable retainers, enable the ball assemblies to be pre-manufactured and assembled as self-contained ball modules that remain assembled prior to being united with the trunions and ball guides.
The invention has the further advantage of providing a yieldable retainer that, when the ball assemblies are mounted on the trunions and disposed in the ball guides, yield out of the way during normal joint operation to permit the inner ball to slide axially relative to the outer ball beyond the retainers. As such, the invention provides the advantageous assembly benefits without impairing the operation of the joint.
The invention has the further advantage of providing the subject yieldable retention of the inner ball without having to increase the radial size of the joint, which would be necessary if rigid, non-yieldable retainers were employed in overlapping relation to the inner ball, but with sufficient clearance to accommodate full axial sliding travel of the inner ball relative to the outer ball during normal operation of the joint. The yieldable retainer, extended into the axial path, is effective to capture the inner ball prior to assembly, yet yields out of the way during normal operation to accommodate full axial travel of the inner ball relative to the outer ball in a relatively smaller package size.
The invention has the further advantage of being readily adaptable to existing and new tripot product applications.
According to a further aspect of the invention, the yieldable retainer is one that is elastically deformable such that the retainer returns to the axial sliding path once the inner ball slides axially inwardly of a retainer. Such restoration of the yieldable retainer facilitates servicing of the tripot joint by maintaining axial retention of the inner ball relative to the outer ball as a self-supporting ball module upon removal of the ball assemblies from the ball channels and trunnions.


A prosthesis for the replacement of a diseased or traumatized facet of a mammalian vertebra includes a surface that articulates with another prosthetic facet or a natural facet, a portion that replaces at least a bony portion of the diseased or traumatized spine facet which is to be replaced, and an element to attach the prosthesis to the vertebra in a manner that does not require attachment to or abutment against the posterior arch. A method of installing the prosthesis includes the steps of resecting at least a portion of a facet and attaching the prosthesis in a manner that does not require attachment or abutment against the posterior arch.

1. Field of the Invention
The present invention relates to surgical devices and methods to replace a damaged, diseased, or otherwise painful spinal facet joint.
2. Description of Related Art
Traumatic, inflammatory, metabolic, synovial, neoplastic, and degenerative disorders of the spine can produce debilitating pain that can have severe socioeconomic and psychological effects. One of the most common surgical interventions today is arthrodesis, or spine fusion, of one or more motion segments, with approximately 300,000 procedures performed annually in the United States. Clinical success varies considerably, depending upon technique and indications, and consideration must be given to the concomitant risks and complications. For example, it has been shown that spine fusion decreases function by limiting the range of motion for patients in flexion, extension, rotation, and lateral bending. Furthermore, it is believed that spine fusion creates increased stresses and, therefore, accelerated degeneration of adjacent non-fused motion segments. Additionally, pseudoarthrosis, as a result of an incomplete or ineffective fusion, may reduce or even eliminate pain relief for the patient. Finally, the fusion device, whether artificial or biological, may migrate out of the fusion site.
Recently, several attempts have been made to recreate the natural biomechanics of the spine by use of an artificial disc. Artificial discs provide for articulation between vertebral bodies to recreate the full range of motion allowed by the elastic properties of the natural intervertebral disc which directly connects two opposed vertebral bodies.
However, the artificial discs proposed to date do not fully address the mechanics of motion of the spinal column. In addition to the intervertebral disc, posterior elements called the facet joints help to support axial, torsional and shear loads that act on the spinal column. Furthermore, the facet joints are diarthroidal joints that provide both sliding articulation and load transmission features. The effects of their absence as a result of facetectomy is believed to produce significant decreases in the stiffness of the spinal column in all planes of motion: flexion and extension, lateral bending, and rotation. Furthermore, contraindications for artificial discs include arthritic facet joints, absent facet joints, severe facet joint tropism or otherwise deformed facet joints.
U.S. Pat. No. Re. 36,758 to Fitz discloses an artificial facet joint where the inferior facet, the mating superior facet, or both, are covered with a cap. The cap requires no preparation of the bone or articular surfaces; it covers and, therefore, preserves the bony and articular structure.
The capping of the facet has several potential disadvantages. If the facet joint is osteoarthritic, a cap will not remove the source of the pain. Additionally, at least in the case of surface replacements for osteoarthritis femoral heads, the capping of articular bone ends has proven to lead to clinical failure by means of mechanical loosening. The clinical failure is hypothesized to be a sequela of disrupting the periosteum and ligamentum teres femoris, both serving a nutrition delivery role to the femoral head, thereby leading to avascular necrosis of the bony support structure for the surface replacement. Another potential disadvantage is that in order to accommodate the wide variability in anatomical morphology of the facets, not only between individuals but also between levels within the spinal column, a very wide variety of sizes and shapes would be required.
U.S. Pat. No. 6,132,464 to Martin discloses a spinal facet joint prosthesis that is supported on the lamina, or the posterior arch of the vertebra. Extending from this support structure are inferior and/or superior blades that replace the cartilage at the facet joint. Like the Fitz design, the Martin prosthesis generally preserves existing bony structures and therefore does not address pathologies which affect the bone of the facets in addition to affecting the associated cartilage. Furthermore, the Martin invention requires a mating condition between the prosthesis and the lamina, or the posterior arch, that is a thin base of curved bone that carries all four facets and the spinous process. Since the posterior arch is a very complex and highly variable anatomic surface, it would be very difficult to design a prosthesis that provides reproducible positioning to correctly locate the cartilage-replacing blades for the facet joints.
Another approach to surgical intervention for spinal facets is provided in WO9848717A1 to Villaret. While Villaret teaches the replacement of spine facets, the replacement is interlocked in a manner to immobilize the joint.
Facet joint replacement in conjunction with artificial disc replacements represent a unique solution to recreating a fully functional motion segment that is compromised due to disease or trauma. Together, facet joint and disc replacement can eliminate all sources of pain, return full function and range of motion, and completely restore the natural biomechanics of the spinal column. Additionally, degenerative or traumatized facet joints may be replaced in the absence of disc replacement when the natural intervertebral disc is unaffected by the disease or trauma.
It would therefore be an improvement in the art to provide a vertebral facet replacement device and method that replaces a bony portion of the facets so as to remove the source of arthritic, traumatic, or other disease mediated pain.
It is an object of the invention to provide an artificial vertebral facet that replaces the cartilage and a portion of the bone of a facet.
It is a further object of the invention to provide a method for preparing a facet for the installation of an artificial vertebral facet.
It is another object to provide a method for replacing a spinal facet.
It is yet another object of the invention to provide a total vertebral facet joint replacement.
In the preferred embodiment, an inferior facet of a superior vertebra is resected at the base of the facet where it connects to the posterior arch. The fin of a prosthetic inferior facet is pressed into the interior bone space of the posterior arch. Alternatively, a tool, such as a broach or punch, may be used to first prepare a space for the fin within the posterior arch.
Alternatively, or in addition, a superior facet of an inferior vertebra that articulates with the inferior facet is resected at the base of the facet where it connects to the pedicle. The post of a prosthetic superior facet is pressed into the interior bone space of the pedicle. Alternatively, a tool, such as a broach or punch, may be used to first prepare a space for the post within the pedicle.
The post and the fin may be porous coated to promote bone ingrowth in order to achieve long term fixation. Acute fixation is provided by a press fit between the post or fin and the internal surface of the bone. The porous coating may carry osteoconductive agents, such as hydroxylapatite, calcium sulfate, or demineralized bone matrix. Alternatively, the porous coating may carry osteoinductive agents, such as bone morphogenic proteins, including rhBMP-2 and rhBMP-7.
Another embodiment of the present invention provides a flange extending from the prosthetic facet. The flange is oriented relative to the body of the prosthesis such that when the flange is placed against the pedicle and in a manner such that the planar surface of the flange is perpendicular to the axis of the pedicle interior bone canal, the articulating surface of the prosthesis will be properly positioned to match the articulating surface of the natural facet. The flange includes a hole for the passage of a fastener to securely attach the prosthesis to the pedicle. The fastener can be a screw, spike, tack, staple, or the like.
Because the present invention allows for the individual replacements of facets, only compromised facets need be replaced. For example, if only one facet is affected by disease or trauma, it can be resected and replaced with a facet prosthesis that articulates with an opposing natural facet.
The present invention has numerous advantages over the prior art. One advantage is that the quality of attachment of the prosthesis is improved. The present invention provides a precise and tight press fit into bones, as opposed to relying on prosthetic surfaces mating with highly complex and variable external surfaces of the vertebra, such as the posterior arch or facet. Another advantage is that the optional porous coating is placed into interior bone spaces where porous coatings have proven to achieve bone ingrowth for excellent long term fixation strength. This ability to achieve bone ingrowth is uncertain for the prior art devices that engage the external bone surfaces of the vertebra. Yet another advantage lies in the removal of the facet bone structure; where the facet bone is involved in the disease pathology or the trauma that compromised the articular or cartilaginous surface of the facet, resection provides a means for ensuring that all pain associated with the disease or trauma is removed and the true joint line is restored. With prior art devices, the bony structure of the facets was generally left intact.
The above, and other objects, features and advantages of the present invention, will become apparent from the following description which is to be read in conjunction with the accompanying drawings.


A resin infusion repair device and method for repairing a wooden boat deck having a repair area that includes voids between the planking of the boat deck and the as built surface under the boat deck planking. A vacuum cover provides an airtight cover of the repair area. A vacuum suction line is inserted into the vacuum cover. A vacuum pump is connected to the vacuum suction line and provides vacuum suction at the repair area. A resin supply line is inserted through the vacuum cover. A resin supply source is connected to the resin supply line. The vacuum pump provides a vacuum suction that draws resin from resin supply source through the resin supply line and into the repair area so that the voids are all filled with the resin. In a preferred embodiment, the wooden boat deck is a teak boat deck.

The quality of wooden decks for expensive yachts is very important. Typically, the top surface of these decks is natural teak wood separated with flexible joints (caulk seams) which allow the individual planks of teak (battens & trims) to expand and contract as the wood's moisture content changes with the surrounding environment. These elements (battens, trims and caulking) are always attached to a prepared surface which is normally the same material as the ship's hull. These materials include wood, alloy, steel, fiberglass, or others. This surface is called the "as-built surface" and it must be properly prepared before a teak deck is attached to it. This prepared as built surface is not part of the teak deck. However, the critical joint between these two surfaces, the teak deck and the prepared as built surface is part of the teak deck. In some cases, the teak elements are attached with mechanical fasteners to the surface below and more recently with adhesive only. However, sometimes both fasteners and adhesive is applied to secure the teak deck elements to the prepared as built surface below. Regardless of the method used the desired goal of the current art form of attaching a teak deck to the prepared as built hull surface of a boat, yacht or ship is to provide a permanent, void free, watertight bond between the two surfaces. However, it is a well-known fact that many teak decks are replaced well before the teak wears out. This is often due simply to the fact that a permanent, void free, watertight seal was not achieved between the teak elements and the prepared as built surface during the original installation process. This is distressing since these types of failures normally cause the early removal and replacement of the teak. When replacing an existing teak deck the new teak must be sourced from a limited supply of a rare natural resource.
Teak deck parts are limited in scope and the types of failures well known. The caulking can release allowing water between the caulking and the wood elements. The wood can fail or crack allowing water into the wood to the bottom of the crack. Water can get under the teak deck, between the teak elements and the prepared as built surface if a permanent, void free water bond was not achieved during the construction process. And adhesives and mechanical fasteners can fail for a number of reasons from simply not cleaning the surfaces to improper mixing. There is a clear difference between the normal effects of simple caulk seam failure or a random cracked batten vice the effects of water being trapped under the teak deck. In truth the caulk seams between the individual pieces of teak will fail sooner or later allowing water to seep to the bottom of the seam. It is also normal for a few battens of wood to develop cracks during their life time. There are simply too many seams and too many individual pieces of teak in a teak deck for these elements to remain perfect. When the caulking starts to fail or a random batten cracks on a properly installed teak deck, which has a permanent, void free, water tight bond between the teak elements and the prepared surface below it is not a significant issue. Water slowly working its way down a defective caulk seam or through a crack has no place to go once it reaches a permanent water tight adhesive joint. It is at this permanent, void free, watertight bond holding the teak pieces or teak panels in place that the deck remains structurally sound even if water is in the seams or in cracks in the wood. These water filled seams or water filled cracks of wood do create a problem but one which can easily be remedied by re-seaming the teak deck or replacing a few pieces of defective teakwood. These actions restore the teak deck's water integrity and extend its service life. In other cases, the result of water migrating down through the caulk seams or cracked battens is likely to allow water to penetrate into one of many voids between the teak elements and the prepared hull surface, filling them with water. These voids normally result from a defective installation process, or are created by one of a multitude of possible adhesive failures, or for other reasons.
Any leakage of water from the top surface of a teak deck downward allowing fluid to become trapped in the underlying structure is often catastrophic and can lead to the early structural failure of the entire teak deck necessitating its replacement. This situation can worsen as corrosion of the yacht's structural surfaces can begin. This is due to the fact that "trapped fluid" normally cannot escape, and because fluid is not readily compressible, it is the cause of many teak deck failures. Water trapped in a space under the teak deck acts as a hydraulic fluid when pressure is applied to the top surface (someone stepping on the deck above the area with water filled voids). The water is forced outward creating a larger space in the underlying deck, opening more caulk seams, filling more voids, and causing the teak to further separate from the prepared hull surface. This larger space can now accept more water entering from ever expanding failures. The process often accelerates as water is the world's most common universal corrosive agent: corrosion begins, adhesives fail, fasteners fail, caulking fails, and the teak deck releases. New teak from the rain forest is then required to replace it.
To fully understand the background, a more detailed description of a teak deck's construction is required. The traditional method used for decades by shipwrights around the world is a well-known art and involves planking the deck by independently shaping and attaching each individual strip or batten of wood with mechanical fasteners, some type of adhesive, or both. A newer method was described in U.S. Pat. No. 4,351,256 filed in February of 1980. It involves constructing a teak deck off the boat, using a backing material, and then taking the teak deck in large panels to the yacht for installation. This method is again secured with mechanical fasteners, adhesives or both. In either case the procedure begins with the existing structure or skin of the ship which can be described as the "as-built deck". An alternate technique for installing teak decks is described in U.S. Pat. No. 7,506,598 issue to Applicant.
As-built decks are normally made of the same material as the ship; i.e., steel, aluminum, fiberglass, epoxy, or wood. Regardless of the material, the as-built deck is almost always uneven and unprotected. Prior to covering it with teak wood, the as-built deck must first be cleaned and protected with some kind of coating or primer to protect it from corrosion and other damage. Following the primer coat (or coats), these uneven decks must be filled with a fairing compound to make them smooth and to make them conform to a desired camber, sheer, and or slope. This will ensure water drains from the finished deck to the desired drain locations. Proper fairing of the as-built deck is critical to ensure the final covering of wood is smooth and that there are no voids underneath it. In fact, improper fairing alone can account for many deck failures as the wood elements could not be properly pressed into the valleys and over the highs of a rolling improperly faired as built surface. One of the reasons to add fairing to an as built surface prior to installing the teak deck is to provide a perfectly smooth surface. For some projects after the fairing is completed, the entire area is covered with plywood to provide cleat stock, insulation, expansion and a more suitable surface to attach a wooden deck. It is easier to glue and screw into plywood than steel, fiberglass or aluminum. This procedure is normally referred to as "sub-decking". The top of the sub-deck now becomes the prepared as built surface to which the teak deck will be attached. Once the as-built deck has been faired, and or sub-decked to the desired lines (camber and sheer) and smoothness, the final teakwood covering is attached.
The attachment of the teak deck to the prepared hull surface is the most important structural joint affecting the overall life of a teak deck. The attachment techniques used at this critical joint include mechanical fastenings (screws, bolts, or studs), some type of adhesive (polysulfide, polyurethane, silicon, epoxy, etc.), or both mechanical fasteners and adhesives. It is noted that the current trend is away from mechanical fasteners and toward fasten-less teak decks set only in a selected adhesive. Attaching a teak deck without fasteners eliminates the teak plugs and provides for a clean and neat appearance. However, these installation techniques are problematic and it is difficult, but not impossible, to obtain the necessary permanent, void free, and water tight bond critical to give the teak deck a long life. When a teak deck is installed without fasteners, there is no backup to keep the deck in place if the adhesive fails. Therefore, cleaning must be done, adequate adhesive must be applied, adequate evenly applied pressure (with the use of weights, pressure bars, pressure sticks, vacuum, or other means as specified by the adhesive manufacturer), drying times observed; and in all cases careful attention must be paid to the manufacturer's mixing and application instructions. It is critical to properly mix the adhesive, properly apply the adhesive, and use adequate amounts of adhesive. Failure to properly accomplish even one of these steps, or failing to get the adhesive in to the teak deck during its "open" time or applying inadequate or uneven pressure on the teak to press it down into the adhesive are all reasons why many teak decks are completed without permanent, void free, and watertight joints between the bottom of the teak and the prepared as built hull surface. Often this fact goes without notice or it is initially considered acceptable. A new teak deck with new caulking is unlikely to allow water into any voids during the normal 12 to 24 month warranty period. If it is 70 percent attached, it is well-fixed to the hull; and with the assistance of gravity it may remain structurally sound during this period. The fact that it has voids between the teak and subdeck surface is not immediately critical. However in time, sometimes sooner than later, the caulk seams will start to fail or a single batten will crack allowing water into these voids. This is when problems will present themselves. At this point, the teak deck begins to immediately show signs of structural failure and the process of structural damage to the hull begins. The current art of repair is to replace the caulking or replace the defective wood in an attempt to re-establish the watertight integrity of the overall teak deck. Often the most defective area is ripped out and replaced. Little attention has been given to a method or system to correct the real structural issue. These are the voids between the teak and the prepared hull which allows a place for water to trap and destroy the deck through hydraulic action.
What is needed is a better method for repairing teak decks having water trapped in voids between the teak deck and the as-built surface.

Vacuum infused repair device and method for teak decks on boats, yachts and ships