SYSTEM AND METHOD FOR TREATMENT OF HEADACHES

Abstract

A method and apparatus for treatment of cervicogenic headaches by transvascular application of stimulation energy to nerves in the neck and head. A catheter equipped with electrodes is inserted into a vertebral or occipital vein in proximity to peripheral nerves that conduct pain signals. An external to the body or implanted generator is used to apply stimulation energy to the targeted nerves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment and best mode of the invention is illustrated in the attached drawings that are described as follows:

FIG. 1 illustrates an exemplary treatment of occipital nerves with a transvascular pulsed RF catheter inserted into an occipital vein.

FIGS. 2 and 3 illustrate a schematic showings of exemplary designs of catheters for transvascular application of energy to adjacent nerves.

FIG. 4 illustrates exemplary advantageous positions of proximity between occipital nerves and occipital arteries suitable for application of therapy.

FIG. 5 illustrates long term implantable embodiment of an IPG and a lead with electrodes in the vertebral vein.

FIG. 6 illustrates long term implantable embodiment of an IPG and a lead with electrodes in the occipital vein

DETAILED DESCRIPTION OF THE INVENTION

This disclosure shows a proposed clinical use in which a RF catheter and controller/generator are applied to treat headaches by transvascular application of pulsed RF energy to occipital nerves. It further shows implantable embodiments of the invention where an implantable pulse generator is connected to at least one transvenous lead placed in a vein in the neck or back of the head of a patient. Specific positions in the venous system advantageous from anatomic stand point (easy to access) and suitable for treatment of cervicogenic pain are disclosed.

FIG. 1 illustrates a patient 101 treated with one embodiment of an RF pulsed catheter system 100 for transvascular denervation of occipital nerves. The catheter 108 is inserted by percutaneous puncture into the external jugular vein 109. The proximal end of the catheter 112 may be connected to an RF energy generator and controller 114. The generator/controller may include electronics to: generate a controlled pulsed signal to be transmitted by distal end 110 of the catheter as an RF pulsed signal; provide user input controls, e.g., display screen and keypad, to enter therapy conditions such as duration of pulse period and select pulse regime (the pulse regimes may be stored electronically in the controller and set by a manufacturer or source of software for the controller); emit alarms indicating an excessive temperature of blood heated by the catheter (which condition may also cause an automatic cessation of the RF pulse regime), and monitor sensors, such as a thermocouple in the catheter or impedance signal from electrodes. An electric connection (wired and/or wireless) between the generator and controller 114 and distal end of the catheter can include signal wires to conduct RF energy and/or temperature signals.

To position the catheter in the patient and after the catheter tip has been inserted into the jugular vein, the distal end 110 of the catheter 108 is advanced into the occipital vein 105 that branches from the jugular vein 109. The movement of the catheter may be accomplished using well known catheter advancement techniques. For example, well known interventional radiology techniques, e.g. including X-ray fluoroscopy, are available to advance a catheter through the jugular vein and into the occipital vein and then through the occipital vein to a region proximate to an occipital nerve.

The distal end 110 of the catheter includes electrodes, such as surface electrodes which may be metallic ring collars made of gold or platinum or other metal alloy commonly used to manufacture catheter electrodes typically used for ablation of tissue embedded in the surface of catheter and coupled by individual wires to the controller/generator 114. Alternatively, electrodes may, for example, be fabricated in a form of spirally wound coils of metal wire. Wound coils allow the catheter to be more flexible in navigating blood vessels. An RF energy field 106 is released from the distal tip electrodes 103 (there can be 2, 4, 8 or more electrodes—FIG. 2). The RF energy field is formed by the electrical signals driving the electrodes, wherein the signals are from the generator/controller. The RF field 106 affects the greater occipital nerve 102 and its branches 107.

The greater occipital nerve 102 is a spinal nerve arising between the first and second cervical vertebrae of the spine 104, along with the lesser occipital nerve. It innervates the scalp at the top of the head on the outside of the skull 113. Disorder of this nerve is one of the causes of cervicogenic headaches, referred to as occipital neuralgias. The greater occipital nerve (GON), lesser occipital nerve (LON) and their branches may be referred to as Occipital Nerves (ON). It is understood that an occipital vein 105 can have several branches (not shown) and that the therapeutic RF catheter can be guided into these branches to deliver the therapeutic field to the nerves.

It is understood that the application of Pulsed RF Energy is given as an example of application of energy to nerve tissue. Ablative RF Energy, heat, cold and pulsed stimulation energy can be also used to disrupt, disable or otherwise modulate conduction of pain signals by nerves.

FIG. 2 is a schematic drawing of a portion of an exemplary catheter 108. The distal end of the catheter 103 is equipped with a soft tip 201 and ring electrodes 202. The soft tip can be instrumental in preventing perforation of a blood vessel. Wires connecting the electrodes to the generator can be molded into the catheter shaft (which may be hollow). The shaft may be a plastic, insulting plastic that is biocompatible with a human body. The catheter shaft is preferably flexible to allow navigation through a tortuous blood vessel.

The catheter 108 may incorporate a thermocouple or a thermistor device 207 to sense a temperature of blood adjacent the thermocouple and there by sense the heating effect of the catheter device. During the procedure, the RF current applied by the generator/controller to the electrodes 202 can be controlled to not exceed the desired temperature. Technology to measure blood temperature with a catheter mounted sensor is well known and commercially available. For example, INNERCOOL (Sun Diego, Calif.) manufactures the Accutrol™ Catheter, which measures a patient's core body temperature during therapeutic hypothermia.

FIG. 3 is a schematic diagram of a cross-section along a longitudinal axis of the catheter 108. The hollow lumen 208 may slidably receive a guidewire 204. The guidewire may be used to direct the distal end 110 of the catheter through the jugular vein and occipital veins. Guidewires are frequently used by interventional radiologists to navigate catheters through blood vessels. The pair of electrodes 202a and 202b can be used to apply pulsed RF energy. Electrodes 202a and 202b can be separated by an expandable inflatable balloon 209a. The purpose of the balloon is to direct energy through the nerve tissue and away from blood inside the vessel. Additional electrodes 203, e.g., an annular array of individual electrode pads, can be mounted on the surface of an expandable balloon 209b. For the occipital application it can be expected that suitable balloons can have, for example, expanded diameter of 4-6 mm and length of 5-8 mm. Electrodes, such as electrodes 202a and 202b can have length of 5 mm and spacing between the electrodes can be, for example, 5 to 10 mm. The expansion of the balloon presses the electrodes against the inside wall surfaces of the occipital vein to improve electric contact between the blood vessel walls and the electrodes. Good electrical contact between the electrodes and blood vessel walls is believed to reduce dissipation of RF energy that is intended to be directed to the occipital nerve (ON). Pulsed RF can be applied between any pair of electrodes chosen by the physician. Multiple electrodes and balloons allow for larger area of denervation and can help reduce the time of the procedure, since the exact position of the occipital nerve in relation to the electrodes may not be known. Published United States Patent Application 2005-0288730 to Mark Deem, entitled “Methods and apparatus for renal neuromodulation” discloses several suitable designs of a transvascular catheter adopted for delivery of RF energy. See also, US Published Application, 2006/0142801 entitled “Methods and Apparatus for Intravascularly-Induced Neuromodulation.” The hollow lumen 210 in the catheter may be coupled to a fluid source that forces fluid into the balloon 209a and 209b through apertures 205a and 205b in the distal end of the catheter. Multiple balloons and electrodes may be used to improve the denervation procedure. Electrodes, such as balloon electrodes 203, can be used to perform measurements, such as tissue impedance to enable better control of the procedure and enable the physician to estimate the effect that the application of pulsed RF had on tissue properties.

FIG. 4 is an illustration of the back of a skull in which the relative positions of occipital nerves and occipital vessels are illustrated. Left and right occipital arteries 401 and 402 can be seen crossing greater occipital nerves 403 and 404 and minor occipital nerves 405 and 406. These intersection points provide suitable sited for RF energy application, such as for example, location 407 treated with the catheter 108. In the illustrated embodiment the physician advances the distal end 110 of the catheter 108 to a position in the occipital vein that he/she determines is proximate to the occipital nerve. Left greater occipital nerve 403 is shown being treated by the distal end 110 of the catheter 108. Multiple electrodes on the distal end 110 allow broader area coverage at the location 407 where the catheter is expected to cross the path of the greater occipital nerve 405. Since nerves cannot be seen on x-ray, the electrodes (visible on X-ray) are positioned using bony landmarks that indicate where the nerves are usually located. Fluoroscopy (x-ray) or CT (Computer Tomography) is used to identify those bony landmarks. Using radiocontrast injection blood vessels can be illuminated to provide additional landmarks for placement of electrodes.

The electrodes on the distal end 110 of the catheter 108 applies RF energy at location 407, for example. The catheter may include a balloon that presses electrodes against the vessel walls of the occipital veins at a location 407 proximate to the occipital nerves. The proximity needed between the catheter electrodes in the distal end 110 and the occipital nerves is determined by the physician positioning the catheter in the veins and should be sufficiently near such that heating (application of Pulsed RF energy) of tissue near the electrodes results in energy being applied to the occipital nerves. Preferably, the occipital nerves are heated to a temperature. It is believed that loss of nerve function occurs at 60 to 65 degrees Centigrade. Accordingly, a target temperature for the occipital nerve may be 60 to 65 degrees. Higher temperatures, e.g., higher than 65 degrees Centigrade, may be applied by RF to block transmission of nerve signals entirely. However, the pulse RF typically may raises tissue temperatures to only about 42 degrees Centigrade, which does not result in substantial tissue injury, and may sufficiently dull nerve function to provide therapeutic relief from headaches, and especially migraine headaches. It can be expected that the described Pulsed RF procedure will need to be repeated every several months to sustain benefit for headache patients.

The physician actuates the controller/generator 114 to apply a regime of pulsed RF energy to the body tissue proximate to the distal end 110 of the catheter. The application of RF energy heats the tissue. The RF regime can vary depending on parameters that include but are not limited to RF field strength, RF pulse width, the shape of the RF pulse, the catheter tip temperature, the number of pulses and/or the interval between pulses (e.g., duty cycle). Suitable field strengths include, for example, strengths of up to about 10,000 V/cm. Suitable pulse widths include, for example, widths of up to about 1 second. Suitable numbers of pulses include, for example, at least one pulse. Further, pulse may be a pulse burst of, for example two to ten pulses within a short duration, such as one second. The pulses within each burst may have varying amplitudes. Suitable intervals between individual pulses or pulse bursts include, for example, intervals less than about 10 seconds and greater than three seconds. The controller may have one or more pulse RF regimes that are selectively stored in the controller. The regimes may be selected by a physician or preprogrammed into the controller and automatically applied when the physician determines that RF energy is to be applied.

The controller may include limiting controls that, for example, limit the temperature increase in the blood adjacent the catheter and as measured by a thermocouple 207. A suitable catheter target temperature can be for example 40 to 42 degrees Centigrade. An exemplary maximum temperature of the blood adjacent the catheter (as sensed by the thermocouple) may be 45 to 55 degrees Centigrade and an exemplary maximum temperature rise of blood adjacent the catheter may be 0.1 to 0.5 degree Centigrade per second for temperatures above 33 degrees Centigrade (which is approximately body temperature).

FIG. 5 illustrates a patient 101 treated with one embodiment of an Implanted Pulse Generator (IPG) 501 with an implanted transvascular nerve stimulation lead 502 with electrodes 503 inserted into the vertebral vein 505 to stimulate nerves associated with cervicogenic headaches. Such position of electrodes can be instrumental in stimulating, for example, the dorsal rami of C2 and C3 vertebrae 504 that are known to conduct cervicogenic pain.

Simulators or pulse generators used in this preferred embodiment utilize traditional flexible leads with electrodes. Design and manufacturing of such stimulators is very well understood. A suitable example of an implantable nerve stimulator is the Vagus Nerve Stimulation (VNS™) with the Cyberonics NeuroCybernetic Prosthesis (NCP®) System used for treatment of epilepsy. Other commercially available stimulators are the Genesis Implantable Pulse Generator manufactured by the Advanced Neuromodulation Systems, Inc. (Plano, Tex.) that is used to control pain, and the Medtronic, Inc. (Minneapolis, Minn.) Synergy® Neurostimulation System. These, and many others, state-of-the-art stimulators are fully implantable, externally programmable and operate with a variety of implantable leads and electrodes adapted for long time implantation in the body. With some modifications, stimulators available from Medtronic, Cyberonics and Advanced Neuromodulation Systems can be adapted for this invention. Alternatively, a manufacturing company with right expertise can develop a dedicated stimulator for the invention if the parameters of stimulation are defined.

It is understood that advanced electronic technology and miniaturization allows construction of much smaller “microstimulators”, such as a Bion manufactured by Advanced Bionics of Sylmar, Calif. The Bion's small size allows the entire device to be deployed directly next to the target of stimulation (such as for example a median nerve). Traditional neurostimulation devices consist of an implantable pulse generator (IPG) and electrode lead. Due to the large size of conventional IPGs, this component must be placed away from the site of stimulation in areas such as the chest, abdomen, or buttocks. The electrode lead and often a lengthy extension must then be tunneled under the skin to reach the stimulation site. Implantation of traditional devices involves extensive surgery, sizable scarring, and the possibility of a prominent bulge under the patient's skin. The Bion implantation is a sutureless procedure that uses a set of custom needlelike insertion tools 4 mm in diameter, leaving no visible scar or bulge.

Transvenous Stimulation Experience from Biventricular Pacing (A.K.A. cardiac resynchronization therapy) provides a person skilled in the art with knowledge and expertise in making transvascular stimulation leads. In cardiac resynchronization therapy, an additional lead is placed over the free wall of the left ventricle so that the left and right ventricles are activated simultaneously. Percutaneous placement is now available. The left ventricular lead is placed in one of the branches of the coronary sinus, using one of the commercially available sheath systems. There is no reason to believe that effects and complications of transvenous nerve stimulation using small caliber veins described in this invention will differ significantly from coronary vein (CV) experience.

The use of venous leads for nerve stimulation provides certain advantages over surgical placement of leads that is currently the state of the art. The transvenous access is by far less traumatizing for the patients. Postoperative adhesions and scarring are nearly irrelevant for this mode of stimulation. Increases in electric impedance threshold occur by far less in vein leads than in surgical ones. It is important for preventing postoperative increases in electrical thresholds that leads are securely embedded in their target vein since repetitive chronic vein wall injuries by mobile leads result in progressive fibrotic reorganization of the adjacent vein wall.

FIG. 6 illustrates a patient 101 treated with another embodiment of an Implanted Pulse Generator (IPG) 501 with an implanted transvascular nerve stimulation lead 502. To position the catheter in the patient and after the catheter tip has been inserted into the jugular vein 109, the electrodes 505 of the lead 501 is advanced into the occipital vein 105 that branches from the jugular vein 109.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A method for treating a cervicogenic headache in a human patient having a head and neck, comprising: inserting a catheter into a vein in the neck or a back of the head of the patient, the catheter having a proximal region, a distal region, and at least one electrode mounted on the distal region;advancing the catheter into the vein until the distal region is proximal to a peripheral nerve in the neck or head, anddelivering electric energy to distal region of the catheter to applied the energy to the peripheral nerve.

2. The method as in claim 1 where the vein is an occipital vein.

3. The method as in claim 1 where the vein is a vertebral vein.

4. The method as in claim 1 where energy is at least one of pulsed electric field, ablation electric field and thermal energy.

5. The method as in claim 1, where the peripheral nerve is at least one of a dorsal rami of C2 and C3; a superficial medial branch of C3; a C2-C3 zygapophyseal joint; and afferents from cervical nerves C1-C3.

6. The method as in claim 1 wherein the peripheral nerve is heated to at least 60 degrees Centigrade by the delivery of the electrical energy.

7. The method as in claim 6 further comprising minimizing heating of tissue proximate the peripheral nerve by delivering the pulse energy to the peripheral nerve from a catheter tip positioned proximate to the nerve.

8. The method as in claim 6 further comprising monitoring a blood temperature proximate to the peripheral nerve and, if the monitored blood temperature exceeds a predetermined temperature threshold, reducing the amount of delivered electrical energy or ceasing the delivery of electrical energy.

9. The method as in claim 6 further comprising the patient adjusting at least one parameter of the delivery of electrical energy, wherein the patient makes the adjustment based on headaches felt by the patient.

10. A method for treating a cervicogenic headache in a human patient having a neck and head, the method comprising: implanting a stimulation lead with at least one electrode into a vein in the neck or head of the patient;where the at least one electrode is positioned in the vein of the patient proximal to a peripheral nerve, andimplanting a pulse generator device in the patient;electrically coupling the pulse generator to the at least one electrode, anddelivering electric energy from the pulse generator to the electrodes adjacent to the peripheral nerve.

11. The method as in claim 10 where the peripheral nerve is at least one of nerve roots, spinal ganglia, nerve plexus outside a vertebral column or more distal peripheral portion of the targeted nerve, and a nerve in a C1-C3 vertebrae.

12. The method as in claim 11 where the at least one electrode is a plurality of stimulation electrodes within a vertebral vein of the patient.

13. The method as in claim 10 wherein the peripheral nerve is heated to at least 60 degrees Centigrade by the delivery of the electrical energy.

14. The method as in claim 13 further comprising minimizing heating of tissue proximate the peripheral nerve by delivering the pulse energy to the peripheral nerve from a catheter tip positioned proximate to the nerve.

15. The method as in claim 13 further comprising monitoring a blood temperature proximate to the peripheral nerve and, if the monitored blood temperature exceeds a predetermined temperature threshold, reducing the amount of delivered electrical energy or ceasing the delivery of electrical energy.

16. The method as in claim 15 wherein the blood temperature is monitory by a temperature sensor on a catheter positioned in a blood vessel proximate to the peripheral nerve.

17. The method as in claim 13 further comprising the patient adjusting at least one parameter of the delivery of electrical energy, wherein the patient makes the adjustment based on headaches felt by the patient.

18. A method to treat a headache in a human patient having a head and neck, comprising: positioning a distal section of a catheter in vein in the neck or the head of the patient, wherein the distal section includes at least one electrode;advancing the catheter into the vein until the at least one electrode is proximal to a peripheral nerve, anddelivering electric energy to the electrode while proximate to the nerve.

19. The method in claim 18 further comprising heating the peripheral nerve using the energy delivered to the at least one electrode.

20. The method in claim 18 wherein the vein is an occipital or vertebral vein.