Abstract:
Methods and devices are disclosed that provide treatment for neurological strokes and other conditions related to obstructed, hemorrhagic or compromised vascular circulation.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional application having Ser. No. 60/259837, filed Jan. 5, 2001, entitled “METHODS and DEVICES FOR TREATMENT OF NEUROLOGIC STROKE”, which application is incorporated herein by reference in its entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    The present invention relates generally to the treatment of neurologic strokes. Methods and devices are disclosed in the context of treating neurologic stroke using vibrational energies to control blood flow to and from the brain tissue. 
       BACKGROUND OF INVENTION 
       [0003]    A number of therapies are available for treating neurological stroke. Drugs and devices are used commonly to attempt to open arteries and veins that are occluded. In some instances, vibrational energy is used to ablate the occlusion causing the stroke. This invention uses vibrational energy to initiate the physiologic phenomenon of vasodilation and/or vasoconstriction in order to re-supply the brain tissue distal of the vessel segment with the occlusion. 
       SUMMARY 
       [0004]    It is known that various frequencies of vibrational energy can cause arteries, veins and capillary beds to dilate or constrict. The terms for such phenomena are vasodilations and vasoconstriction. These phenomena can thus be use to treat victims of neurological strokes. Typically, low frequencies cause dilation while high frequencies cause constriction. Low frequencies generally have a higher average power than high frequencies. Low frequencies tend to travel longer distance with less attenuation than high frequencies. 
         [0005]    In the case of hemorrhagic strokes, a ruptured artery results in the lack of distal blood flow to brain tissues. 
         [0006]    In the case of an ischemic stroke, a blood clot or other debris such as loose atheroma typically occludes an artery. Sometimes the vessels become occluded due to vasospasm. When the artery is occluded, the blood flow to certain brain tissues is prevented. The lack of blood to the tissue ultimately will result in permanent damage to the tissue and result in neurological function compromise or death. 
         [0007]    The current treatment of patients suffering from ischemic strokes include thrombolytic drugs to dissolve clots, mechanical intervention with devices to break up or remove the obstruction, or if the patient arrives to a treatment facility (e.g. hospital) too late for intervention to be of benefit (brain tissue damage is irreversible), than minimum treatment is administered other than rehab for the effects of the stroke. There have been efforts at utilizing ultrasonic and sonic energies to break up the clot or expedite the efficacy of thrombolytics. These technologies have been integrated into intravascular catheter systems or external transducers and have met with safety or effectiveness deficits. The primary intention of this particular invention is to cause controlled and therapeutic vasodilation through the use of vibrational energies to establish blood flow to the regions of the previously fed by the occluded artery. 
         [0008]    By utilizing certain frequencies and amplitudes of vibrational energies, arteries, smaller collateral arteries, dormant arteries, or capillary beds can be prompted to expand or open in order to increase, complement or restore blood flow to brain tissues that were fed by the occluded or ruptured artery. Not only can arterial blood flow increase, but brain venous flow can also increase. This can result in a lower capillary bed pressure and allows important oxygenated blood to reach the important brain tissues faster. The flow of cerebrospinal fluids can also be controlled utilizing the same vibrational technologies. This can be useful in the treatment of ailments such as hydrocephalus and papilledema. 
         [0009]    Alternatively, certain vibrational frequencies and amplitudes of vibrational energies can cause arteries and/or veins to constrict. These phenomena can be used to reduce or limit the amount of blood flow to certain tissues in order to increase the available blood supply to affected tissues. In this case, the blood supply to the outside of the head, scalp or face can be reduced or limited thus forcing more blood to the brain and the affected tissues. This extra supply may result in an increase of blood pressure within the brain. The increase in pressure may supplement the vibrational energy or alone cause the vessels to expand or be forced open. 
         [0010]    A multi-frequency or multi-harmonic source may be utilized to simultaneously obtain vasodilation and vasoconstriction. Typically, low frequencies cause dilation while high frequencies cause constriction. Low frequencies generally have a higher average power than high frequencies. Low frequencies tend to travel longer distance with less attenuation than high frequencies. 
         [0011]    Since it is known that lower frequencies have more average power and thus travel farther and deeper than higher frequencies, the lower frequencies could be targeted directly to the brain to expand the deeper vessels and increase flow; higher frequencies can be targeted at the outer portion of the brain, head, and or/face in order to cause constriction of the resident vessels. This scenario thus creates a bi-modal therapy. However, this scenario may be reversed and/or complemented based on clinical need. Selection of frequency and power can also cause the vessels near the brain periphery to expand in order to increase flow to these regions. 
         [0012]    Impedance matching the source to the anatomy can also provide beneficial effects and efficiencies. 
         [0013]    The vibrational energies can be delivered by various sources. Such sources may be sonic transducers (i.e., sonic, ultrasonic, subsonic, etc), mechanical transducers, electromechanical vibrator, mechanical vibrators, piezoelectric sources, etc), pneumatic, hydraulic, magnetostrictive, or other types that result in the transmission of vibrational energy to the desired target. Hydraulic and pneumatic designs would lend themselves to being used in magnetic resonance imaging (MRI) systems because they could be made without metallic or conductive material that would affect the MRI. This would allow MRI imaging and visualization of the affect of the vibrational energies. In these designs, a pillow like device could be driven hydraulically or pneumatically. The patient&#39;s head would rest on the pillow and absorb the vibrational energy during the procedure. The pumps and compressor systems can be located outside of the MRI suite with tubings and conduits running from the systems to the patient site and connected, in one scenario, the pillow. All components can be made of materials that are not attracted to the magnetic energy and that do no affect the MR image. Likewise, the treatment device can be used in conjunction with CAT scan, x-rays, or other imaging and diagnostic equipment. Again, the frequency and amplitude of the desired sources may be designed to gain the desired affect. The frequency range of subsonic to ultrasonic can be used. Likewise, the vibration may be transmitted in a pulsed form or periodically as required. Complex waveforms or combinations of pulses and continuous waveforms may be utilized. These sources can be directly in contact with the external surface if the patients head, face or upper extremities. Likewise, the sources may be utilized in a non-contact fashion such as in the case of sonic transducers. In the addition, the sources may be inserted in the patient near the desired treatment area via the vasculature, conduits, and anatomic openings or surgically with endoscopic techniques as examples. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Throughout the several views of the drawings several illustrative embodiments of the invention are disclosed. It should be understood that various modifications of the embodiments might be made without departing from the scope of the invention. Throughout the views identical reference numerals depict equivalent structure wherein: 
           [0015]      FIG. 1 . is a diagram of a patients head residing on a vibrational source 
           [0016]      FIG. 2 . is a schematic diagram of the head with a discrete vibrational source attached 
           [0017]      FIG. 3 . is a schematic diagram of a head with a remote transducer directing energy towards it. 
           [0018]      FIG. 4 . is a schematic diagram of a head within a vibrational therapeutic helmet 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Implementation of the source into various design embodiments is possible. For example,  FIG. 1  shows pillow-like device  14  that may be fashioned with a vibration source for convenience, patient comfort, effectiveness and affectivity. A conformable structure would ensure a broader and efficient application of the vibration energy to the head. The pillow could be filled with a fluid or other material in order to get efficient transmission of energy through the patients skull to her brain. Likewise,  FIG. 2  shows a design that can be formed into an element  22  that makes contact in an area of the head so as to focus the energy towards specific locations within the head. The vibration source  26  can be built into the element  22  or be, as in this case, a separate component with connections  24  to the element  22 . Impedance matching the vibration source to the human anatomy  20  would also be of great benefit for efficiency and/or affectivity. Other means of creating conformable sources are envisioned. The surfaces making contact with the anatomy may consist of materials with varying densities and physical properties in order to optimize and direct energy transmission to desired targets of the anatomy. For example, portions may be fabricated of higher density and low density materials. 
         [0020]    Since higher density materials generally transmit vibrational energy better than lower density portions, the higher density portions can be arranged in order to make contact at the desired anatomical locations where vibrational energy transmission is desire. Alternatively, low density portions may be arranged to contact the anatomy where vibrational energy is not desired. This can provide for optimized treatment results as well as patient comfort. Viscoelastic materials can also provide design and treatment options. Another design alternative can use physical gaps or protrusions to direct the energy. Other design alternatives could use more discrete sources for targeted or localized effects. Theses sources could be attached to specific portions or locations of the anatomy in order to achieve the desired affect. The sources could be secured to the patient with straps, glues, tapes, stitched, adhesives, Velcro, magnets, etc. 
         [0021]    In the remote application of energy, sonic horns or transducers could be aimed at the entire head or certain portions of the head.  FIG. 3  shows a potential system that directs vibrational energy  34  to the head  30  via an ultrasonic tranducer  32 . The vibrational energy is imparted to the brain  36 . 
         [0022]    The effectiveness of complementary therapeutic drugs, biologics, or other agents may benefits from the application of vibration energy from one of the aforementioned devices. The vibrational energy may help localize the effects, increase the rate and amount of absorption into tissues, or may increase the speed of the effectiveness of thrombolytics or other drugs that can be used to facilitate the treatment of strokes. The application of vibrational energy to the head may also reduce pain and swelling and edema that is associated with strokes. Likewise, the aforementioned devices and methods can also be used to enhance diagnostic imaging procedures such as fluoroscopy, CT, MRI, PET scans. With the application of vibrational energy to various parts of the anatomy, the imaging agents administered to the patient in conjunction with these diagnostic imaging procedures can be distributed more broadly to the desired regions. For example, distal vascular circulatory systems and collateral systems can be identified when the arteries or veins open up and except the imaging agents. Breast exams can be made more effective when imaging agents are more efficiently distributed through the tissue and potential cancerous tumors. During surgical procedures, the vascular anatomy can be identified so as to control bleeding or to spare important vessels from cutting or ligation. The same methods and devices can be modified to assist in the treatment of people suffering from hypothermia or the salvage of frozen limbs by rapidly increasing the circulation of the tissues with oxygenated, warm blood. Likewise, perfusion with blood and oxygen of the anatomy can be made more effective with these same approaches. This can assist in the recovery for victims of poisoning or asphyxiation from toxic gases and substances. 
         [0023]    In all cases, the use of these sources may be utilized in emergency settings inside or outside the hospital or in a more controlled environment such as in the ICU, hospital room, catheterization lab, surgical suites, convalescent homes or outpatients facilities. It is envisioned that a version of the source is designed to be battery operated or can be plugged into an ambulance&#39;s power source. The battery can be rechargeable. The portability of the source is a benefit for use in emergency situations or for use in ambulance (ground or air). Likewise, portable sources can be placed in public areas such as is the case of placing portable defibrillators in public facilities. The entire source, or portions thereof, can be made to be a single-use, disposable item. A permanent reusable system may also be implemented. Other features may be implemented into the source such as heating, cooling, or electrical stimulation in order to enhance or complement the treatment. The entire therapeutic unit may be contained in a helmet, hat, head band, cuff, wrap, clothing article, bed, gurney, chair, or other structure.  FIG. 4  shows a patient  40  wearing a helmet  42  containing a therapeutic unit. The unit can also be incorporated into the patient table of diagnostic imaging such as is used for MRI or CT. In this case, enhanced diagnostic imaging and/or real-time imaging can be performed during therapeutic events. For full-body therapeutic effects, the patient can also be immersed in a fluid bath that transmits vibrational energy. In this case, temperature of the baths can be altered in order to gain various complementary therapeutic effects. Additives to the bath that affect the fluid physical properties such as the density, viscosity, electrical conduction, may provide additional benefits. Low-level electrical stimulation through the bath may also provide analgesic and circulatory benefit. 
         [0024]    The source may also contain one or more of EEG, ECG, and Blood Pressure monitoring systems to diagnose and treat the patient. Temperature probes may be installed for internal or external surface measurements in order to correlate to blood flow. IR sensors can also be used to monitor temperatures. Higher body surface temperatures should correlate to increase blood flow, while lower temps would correlate to decreased flow in a certain area of the anatomy. A closed-loop, feedback system can be incorporated in order to optimally adjust vibration frequencies, vibration amplitudes, heat and cooling temperatures, based on output parameters and monitored physiologic parameters. 
         [0025]    Although this invention is disclosed in the context of treating strokes, the basic principles of the methods and devices may also be used to treat other indications such as peripheral vascular disease or other vasculature, lymphatic systems, tumors, reproductive systems, nervous systems, organs or eyes. It can also be used for cosmetic purposes such as for increasing blood flow through bags under eyes or for bulbous nose syndrome, It can be used for any drug application in order to increase the drug absorption within the tissues or organs by reducing the surface tension of the tissues and cellular matter and matrix by using properly directed vibration energy.