System and method utilizing magnetic steering for placement of stimulation electrodes within brain tissue

Abstract

Systems and methods herein involve placement of an elongated body structure (e.g., catheter) including at least one electrode within brain tissue of a subject to enable delivery of electrical stimulation for therapeutic effect. The body structure is steered along non-linear trajectories within the brain tissue, including magnetic steering (e.g., pulling) via a magnetic field source external to the subject and including linear actuation (e.g., pushing) via an actuator outside the subject. At least one electrode is externally accessible along the elongated body structure to permit electrically conductive contact with brain tissue. A fiber optic shape sensor is arranged within the body structure. If multiple electrode are provided, then each electrode may have an associated conductor extending within the elongated body to enable the electrodes to be individually controlled.

Description

SYSTEM AND METHOD UTILIZING MAGNETIC STEERING FOR PLACEMENT OF STIMULATION ELECTRODES WITHIN BRAIN TISSUECross-Reference to Related Application^)

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 707,504 filed on October 15, 2024, wherein the entire contents of the foregoing application are hereby incorporated by reference herein.Technical Field

[0002] This disclosure relates to a system and method utilizing magnetic steering for placement at least electrode within brain tissue of a subject to permit delivery of electrical stimulation to the brain tissue for therapeutic treatment.Background

[0003] Various neurological disorders involve mesial temporal lobe structures of the brain, such as the hippocampus, amygdala, entorhinal cortex, and other areas, and may not be adequately treated with pharmaceuticals. One such condition is post-traumatic stress disorder, which affects various groups of people, including approximately 7 percent of military veterans. State-of-the-art treatment paradigms, which consist of SSRI pharmacotherapy and cognitive behavioral therapy, often yield limited success, failing in up to 80% of patients. Chronic electrical stimulation of the bilateral amygdala is an experimental therapy that is currently being investigated for treatment-resistant PTSD in veterans, in which electrical stimulation is provided with implanted devices, specifically targeting bilateral amygdala. Scientific efforts in the context of an ongoing study are focused on electrophysiologic biomarkers of PTSD symptoms that may serve as temporal biomarkers for closed-loop stimulation, whereby electrical stimulation is adapted in real time based on recordings obtained from the target structure (as is the case of implantable cardioverter defibrillators). There is considerable heterogeneity in the expression of PTSD across individual patients. For its diagnosis and classification into sub-types, over 20 symptoms are grouped into four clusters: intrusion, avoidance, negative alterations in cognitions and mood, and alterations in arousal and reactivity. One of the reasons for this heterogeneity may be rooted in the complexity of amygdalar microcircuits, which are subdivided into three primary sub-nuclei (basolateral (BLA), centromedial (CMA) and superficial (SFA)), as well as their differential connectivity with other brain regions involved in emotional regulation.

[0004] Surgical implantation of Responsive Neurostimulation (RNS) electrodes in the hippocampus for treatment of drug-resistant epilepsy (DRE) is also being investigated. The surgical goal of the traditional approach is to place all stimulating contacts within the hippocampus. Recent data suggest that coverage of the anteromedial aspect of the hippocampus is predictive of enhanced seizure outcomes.

[0005] Current methods for positioning electrodes in brain tissue for electrical stimulation rely on linear trajectories and manual navigation by which electrodes are pushed in from the cortical surface to a pathologic target. This limits the ability to reach certain regions of brain tissue accurately and safely. Given the anatomical intricacies of target structures particularly the hippocampal head and amygdala, which deviate medially from the hippocampal body's long axis, electrode deployment often requires multiple separate trajectories. Each trajectory brings the risk of hemorrhage due to vascular damage, especially to vessels near the targeted structures within the superficial cortical areas. The risk of hemorrhage from damaging intracranial vessels is directly proportional to the number of passes through brain parenchyma, with each trajectory increasing the risk of intracranial hemorrhage by approximately 1 percent. Additionally, linear insertion of electrodes also limits the ability of electrodes to stimulate large areas of brain tissues not aligned with the linear path of insertion. Achieving desired safety and efficacy of clinical outcomes may not be possible within the constraints imposed by the number of electrodes a single electrical stimulation device can accommodate and by using only linear trajectories.

[0006] An ability to provide flexible steering of intracranial leads would provide a significant benefit to overcome current limitations of linear implant configuration to improve both high- fidelity recordings of electrical activity from individual brain areas (e.g., amygdalar and hippocampal sub-nuclei) as well as their selective neuromodulation with chronic electrical stimulation, with the ultimate goal of personalized neuromodulation to treat various medical indications, such as PTSD and DRE.Summary

[0007] Aspects of the present disclosure relate to a system and a method for precise placement of at least one electrode within brain tissue of a subject to enable delivery of electrical stimulation to the brain tissue for therapeutic effect. Such placement may involve transit of a steerable assembly having an elongated body structure over non-linear trajectories within the brain tissue, including magnetic steering via a magnetic field source located outsidethe subject interacting with a premagnetized material of the steerable assembly, and including a linear actuator (also located outside the subject) coupled with the elongated body structure and configured to advance at least a portion of the elongated body structure within the brain tissue. At least one electrode is externally accessible along the elongated body structure to permit electrically conductive contact with brain tissue. The at least one electrode is configured to be coupled to a voltage source (or other appropriate electrical driver, also located outside the subject) to permit electrical stimulation to be delivered through the electrode(s) to one or more areas of the brain tissue. If multiple electrode are provided, then in certain embodiments each electrode may have an associated conductor extending within the elongated body to permit each such electrode to be individually controlled.

[0008] In one aspect, the disclosure relates to a system for placement of at least one electrode within brain tissue to enable delivery of electrical stimulation, the system comprising: at least one magnetic field source; a steerable assembly that comprises: an elongated body structure having a proximal end and a distal end, the at least one electrode arranged along an exterior of the elongated body structure, a premagnetized material arranged closer to a distal end than to a proximal end of the elongated body structure, and fiber optic shape sensor within the elongated body structure; and a steerable assembly that comprises: an elongated body structure having a proximal end and a distal end, the at least one electrode arranged along an exterior of the elongated body structure, a premagnetized material arranged closer to a distal end than to a proximal end of the elongated body structure, and fiber optic shape sensor within the elongated body structure; wherein the at least one magnetic field source is configured to interact with the premagnetized material to effectuate steering of the distal end of the elongated body structure when the distal end is arranged within the brain tissue; and wherein the at least one electrode is configured to be coupled to a voltage source to permit electrical signals to be delivered through the at least one electrode to one or more areas of the brain tissue.

[0009] In certain embodiments, the at least one electrode comprises a plurality of electrodes arranged at different positions between the proximal end and the distal end of the elongated body structure.

[0010] In certain embodiments, each electrode of the plurality of electrodes is generally tubular in shape and locally extends around substantially an entirety of an outer perimeter of the elongated body structure.

[0011] In certain embodiments, the system further comprises at least one robotic arm configured to move the at least one magnetic field source.

[0012] In certain embodiments, the premagnetized material comprises at least one of a permanent magnet, a ferromagnetic material, and an electromagnet.

[0013] In certain embodiments, the premagnetized material is arranged within an interior of the elongated body structure.

[0014] In certain embodiments, the premagnetized material is configured to be removed from the interior of the elongated body structure while the at least a portion of the elongated body structure is arranged within the brain tissue.

[0015] In certain embodiments, the fiber optic shape sensor comprises one or more optical frequency domain reflectometry (OFDR) sensors.

[0016] In certain embodiments, the fiber optic shape sensor comprises one or more fiber Bragg grating (FBG) sensors.

[0017] In certain embodiments, the system further comprises the voltage source, wherein the at least one processor is further configured to control the voltage source to deliver electrical signals through the at least one electrode to one or more areas of the brain tissue.

[0018] In certain embodiments, the system further comprises one or more magnetic field sensors, wherein the at least one processor is configured to control movement and / or activation of the at least one magnetic field source responsive to outputs of the one or more magnetic field sensors.

[0019] In certain embodiments, the at least one processor is configured to control the at least one magnetic field source and the linear actuator without user intervention.

[0020] In another aspect, the disclosure relates to a method for delivering electrical stimulation to brain tissue using a system as described herein, the method comprising: moving the at least one magnetic field source to effectuate steering of the distal end of the elongated body structure and advancing the elongated body structure within the brain tissue using the linear actuator to position the one or more electrodes at one or more desired locations within the brain tissue; and operating the voltage source to deliver electrical signals through the one or more electrodes to interact with portions of the brain tissue.

[0021] In certain embodiments, the operating of the voltage source to deliver electrical signals through the one or more electrodes to interact with portions of the brain tissue is configured to treat post-traumatic stress disorders.

[0022] In certain embodiments, the operating of the voltage source to deliver electrical signals through the one or more electrodes to interact with portions of the brain tissue is configured to treat drug-resistant epilepsy.

[0023] In certain embodiments, the one or more electrodes comprises multiple electrodes, and the operating of the voltage source to deliver electrical signals through the one or more electrodes comprises delivering independent electrical signals to individual electrodes of the multiple electrodes.

[0024] In certain embodiments, the moving of the at least one magnetic field source comprises moving the at least one magnetic field source using at least one robotic arm.

[0025] In certain embodiments, one or more magnetic field sensors are provided, and wherein the method further comprises controlling movement and / or activation of the at least one magnetic field source responsive to outputs of the one or more magnetic field sensors.

[0026] In certain embodiments, the method further comprises utilizing three-dimensional trajectory information and a three-dimensional model of the brain tissue to control movement the at least one magnetic field source and control advancement of the elongated body structure within the brain tissue.

[0027] In another aspect, any two or more features of aspects and / or embodiments disclosed herein may be combined for additional advantage.Brief Description of Drawings

[0028] FIG. 1 is a schematic diagram showing interconnections between components of a system for utilizing magnetic steering for placement of a steerable assembly including an elongated body structure with one or more electrodes within brain tissue of a subject, to permit delivery of electrical stimulation to the brain tissue according to one embodiment.

[0029] FIG. 2 is a perspective view of a robotic arm incorporating magnets to serve as an end effector to effectuate steering of an elongated body of a steerable assembly incorporating at least one electrode to permit delivery of electrical stimulation to the brain tissue according to one embodiment.

[0030] FIG. 3 is a schematic side view illustration of a portion of a fiber Bragg grating sensor that may be utilized for determining position of a steerable assembly incorporating at least one electrode to permit delivery of electrical stimulation to the brain tissue according to one embodiment.

[0031] FIG. 4 is a perspective view of robot arm carrying permanent magnets and an elongated body including a fiber optic shape sensor as part of a steerable assembly incorporating electrodes to permit delivery of electrical stimulation to the brain tissueaccording to one embodiment, with inset images of a display showing side and top views of brain tissue with a steerable assembly therein.

[0032] FIG. 5 shows an image of brain tissue at left, with a magnified portion at right showing a portion of the brain tissue with a steerable assembly therein having a curved trajectory therein according to one embodiment, the steerable assembly including four generally cylindrical electrodes that are spaced apart from one another and configured to deliver electrical stimulation to the brain tissue.

[0033] FIG. 6 is a plot of force versus displacement showing forces needed for puncturing and moving through brain tissue for lumens (e.g., catheters) having diameters ranging from 7. 5 to 100 microns.

[0034] FIG. 7 is a plot of magnetic pulling force (in Nm) applied to two 15 kg cubic external magnetic on cylindrical internal magnets of diameters 0.5 to 1.5 mm at different distances ranging from 100 to 200 mm.

[0035] FIG. 8 is a hybrid point to point and path diagram for controlling a steerable assembly having an internal premagnetized material using magnetic steering and avoiding back-tracking according to one embodiment.

[0036] FIG. 9 is a block diagram for a closed-loop control system for steering of an intracranial magnetically steerable assembly according to one embodiment.

[0037] FIG. 10 is a plot of path (Y mm vs. X mm) for manipulation of an elongated body structure having a FOSS sensor and internal magnets through three different curvatures in a stiff phantom gel, tracked using a fiber Bragg grating system.

[0038] FIG. 11 is a plot of path (Y mm vs. X mm) for manipulation of an elongated body having a FOSS sensor and internal magnets through three different curvatures in a soft phantom gel, tracked using a fiber Bragg grating system.

[0039] FIG. 12 provides plots of force (g) versus time (sec) depicting penetration transients and cumulative drag forces on a 3-mm diameter catheter moved through 0.6 agarose gel by a motor-drive force gauge inserted at a rate of 0.33 mm per second, with a mean data plot presented along with upper and lower values of standard deviations of the data.

[0040] FIG. 13 provides plots of force (g) versus time (sec) depicting penetration transients and cumulative drag forces on a 3-mm diameter catheter moved through porcine brain tissue by a motor-drive force gauge inserted at a rate of 0.33 mm per second, with a mean data plot presented along with upper and lower values of standard deviations of the data.

[0041] FIG. 14 illustrates an experimental apparatus for steering an elongated body structure, with a dashed line rectangular inset portion showing an end portion of the elongated body structure.

[0042] FIG. 15A is a top plan view of the path of a magnetically steerable assembly superimposed on a preoperative MRI / CT image of a human brain.

[0043] FIG. 15B is a perspective view of the path of a magnetically steerable assembly superimposed on a three-dimensional image of a cadaver head.

[0044] FIG. 15C-15D provide rear elevational and left side elevational views, respectively, of the items of FIG. 15 A.

[0045] FIG. 16A is a top plan view of the path of a magnetically steerable assembly including FOSS sensors superimposed on a preoperative MRI / CT image of a cadaver brain

[0046] FIG. 16B is a perspective view of the path of a magnetically steerable assembly including FOSS sensors superimposed on a three-dimensional image of a cadaver head.

[0047] FIG. 16C-16D provide rear elevational and left side elevational views, respectively, of the items of FIG. 16 A.

[0048] FIG. 17 is a plot of measured insertion force versus displacement within a cadaver brain of the magnetically steerable assembly of FIG. 16 A.

[0049] FIG. 18 is a plot of steerable assembly deflection in two dimensions according to PyElastica-based simulations measurements of steerable assembly deflection under gravity alone and under combined gravity plus magnetic field conditions.

[0050] FIG. 19 is a schematic diagram of a generalized representation of a computer system that can be included as one or more components of a system or method utilizing magnetic steering and linear actuation for placement of at least one electrode to permit delivery of electrical stimulation to the brain tissue according to one or more embodiments.Detailed Description

[0051] In one or more aspects, the present disclosure relates to a system and method for precise placement of at least one electrode within brain tissue of a subject to enable delivery of electrical stimulation to the brain tissue for therapeutic effect. Such placement may involve transit of a steerable assembly having an elongated body structure over non-linear trajectories within the brain tissue, including magnetic steering via a magnetic field source located outside the subject interacting with a premagnetized material of the steerable assembly, and including a linear actuator (also located outside the subject) coupled with the elongated body structureand configured to advance at least a portion of the elongated body structure within the brain tissue. At least one electrode is externally accessible along the elongated body structure to permit electrically conductive contact with brain tissue. The at least one electrode is configured to be coupled to a voltage source (or other appropriate electrical driver, also located outside the subject) to permit electrical stimulation to be delivered through the electrode(s) to one or more areas of the brain tissue. If multiple electrode are provided, then in certain embodiments each electrode may have an associated conductor extending within the elongated body to permit each such electrode to be individually controlled.

[0052] In certain embodiments, systems and methods disclosed herein enable precise three- dimensional placement of one or more electrodes in brain tissue to electrically stimulate desired areas of the brain (e.g., amygdalar structures) for treatment of PTSD. This system uses magnetic steering to accurately guide a flexible elongated body structure (e.g., a catheter) bearing the electrode(s) through complex brain structures, minimizing damage to surrounding tissues and enhancing the safety and efficacy of the electrical stimulation procedure. Magnetic steering may be aided by linear actuation (e.g., pushing) of the elongated body structure . This technology enables flexible, non-linear trajectories that surpass the limitations of existing manual or linear placement methods, which reduces the risk of injury to critical brain structures, enhancing patient safety during the outcome.

[0053] In certain embodiments, the premagnetized material comprises at least one of a permanent magnet, a ferromagnetic material, and an electromagnet. In certain embodiments, the premagnetized material comprises multiple strategically placed premagnetized material regions within an elongated body structure.

[0054] In certain embodiments, the premagnetized material is arranged within an interior of the elongated body structure. In certain embodiments, the premagnetized material is configured to be removed from the interior of the elongated body structure while the at least a portion of the elongated body structure is arranged within the brain tissue. For example, a premagnetized material may be selectively withdrawn through a passage defined in the elongated body structure.

[0055] The fiber optic shape sensor serves as a tracking apparatus for the elongated body structure to achieve accurate and flexible navigation within brain tissue of a subject, and provides feedback on position and orientation of the elongated body structure relative to anatomical structures of the brain tissue. In certain embodiments, the fiber optic shape sensor comprises one or more fiber Bragg grating (FBG) sensors. In certain embodiments, the fiberoptic shape sensor comprises one or more optical frequency domain reflectometry (OFDR) sensors. OFDR can measure strain and temperature variations along a fiber's length in a distributed manner, thus enabling the reconstruction of complex shapes with higher accuracy. In certain embodiments, real-time tracking data provided by fiber optic shape sensing may be integrated with pre-operative MRI images to minimize the need for invasive live imaging (such as X-ray, MRI, and ultrasound imaging) with its attendant limitations (e.g., radiation exposure, insufficient temporal resolution, and / or incompatibility with magnetic objects).

[0056] In certain embodiments, the system comprises at least one robotic arm configured to move the at least one magnetic field source. In certain embodiments, the at least one robotic arm comprises a six-degree-of-freedom (6-DOF) robotic arm that supports a plurality of magnets to enable application of precise magnetic fields and gradients to steer the elongated body along non-linear trajectories.

[0057] As noted above, a linear actuator is provided (i.e., to perform mechanical pushing of an elongated body structure) in addition to a magnetic steering system, wherein the resulting dual-control approach (mechanical pushing and magnetic steering) allows an elongated body structure to be navigated through complex, curved pathways within brain tissue to reach specific target regions (e.g., amygdalar structures). The mechanical pushing beneficially allows an elongated body structure to be advanced through brain tissue that would be difficult to penetrate with magnetic pulling alone. As the elongated body structure is pushed forward, the external magnetic field generator may be dynamically repositioned in three-dimensional space to generated controlled magnetic fields, thereby exerting torques on premagnetized material(s) of the elongated body structure, to continuously align them with the desired trajectory and enable directional control in three dimensions. The push-pull-hybrid approach allows the elongated body structure to bend and steer through curved anatomical pathways while avoiding critical structures. The integration of magnetic manipulation and real-time tracking enhances the precision of therapeutic delivery of electrical stimulation to ensure that one or more electrodes are accurately guided to target tissues (e.g., amygdalar sub-nuclei) while reducing or minimizing the risk of collateral damage to surrounding healthy tissues.

[0058] In another aspect, the disclosure relates to a method for delivering electrical stimulation to brain tissue utilizing a system as disclosed herein. The method comprises moving at least one magnetic field source to effectuate steering of the distal end of the elongated body structure and advancing the elongated body structure within the brain tissue using the linear actuator to position one or more electrodes at desired locations within the braintissue. The method further comprises operating a voltage source or other electrical driver (located outside a subject) coupled with the electrode(s) to deliver electrical stimulation through the electrode(s) to interact with portions of the brain tissue, such as to ameliorate symptoms of drug-resistant PTSD.

[0059] FIG. 1 schematically illustrates components of a system 100 for placement of one or more electrodes 172A-172C within brain tissue 110 to enable delivery of electrical stimulation according to one embodiment. At lower left, a surgical instrument including an elongated body structure 150 extends through an opening or incision 111 and is positioned within tissue (e.g., brain tissue) 110 of a human body or other animal body. The elongated body structure 150 terminates at a distal end 180 including a tip portion 181 within the brain tissue 110, with the elongated body structure 150 comprising externally accessible electrodes 172A-172C proximate to the distal end 180 of the elongated body structure 150. The elongated body structure further comprises at least one premagnetized material 156 proximate to the distal end 180 (e.g., closer to the distal 180 end than to a proximal end 182 of the elongated body structure 150). The system 100 further includes a fiber optic shape sensor (FOSS) 161 received by the elongated body structure 150. In certain embodiments, the fiber optic shape sensor 161 may include one or more optical frequency domain reflectometry (OFDR) sensors, or one or more fiber Bragg grating (FBG) sensors, associated with an optical fiber of the FOSS 161.

[0060] One or more magnetic field sources that may comprise one or more robotic actuators 114 (e.g., robotic arms, such as 6-degree-of-freedom (6DOF) robotic arms) are arranged external to the body comprising the brain tissue 110 to apply at least one magnetic field to interact with the premagnetized material 156 of the elongated body structure 150 to effectuate steering of the elongated body structure 150. In certain embodiments, a UR16e robotic arm may be used. In certain embodiments, multiple robotic actuators 114 may be provided. Each robotic actuator 114 may be controlled by a motor driver 116 and a processor 130 (e.g., integrated with a microcomputer in certain embodiments), wherein one or more intermediately arranged motor signal converters 117 may also be provided. Desired poses of each robotic actuator 114 may be calculated by the processor 130 and supplied to the motor driver 116 to control movement of the robotic actuator 114. Movement of one or more magnetic end effectors 112A, 112B (which may be embodied in permanent magnet materials, ferromagnetic materials, or electromagnets) may effectuate steering of the elongated body structure 150 when present within tissue (e.g., brain tissue) 110 of an animal (e.g., human) body. In certainembodiments, magnetic end effectors 112A, 112B may be mounted on separate support arms 115A, 115B and spaced apart from one another.

[0061] In certain embodiments, a user input device 119 controllable by user manipulation may be arranged to permit control of the magnetic field source(s) 114 as well as a linear actuator 152 to achieve a desired trajectory of the elongated body structure 150 for positioning one or more electrodes 172A-172C at desired location(s) within the brain tissue 110. One or more feedback actuators 118 are configured to supply haptic feedback to a user (e.g., surgeon or other medical professional) through the user input device 119, wherein such haptic feedback may be proportional to one or more of magnetic field strength, magnetic field direction, etc.). One example of a user input device 119 is a joystick, which may be provided in single or dual forms, optionally augmented with various items such as triggers, buttons, dials, and the like. In certain embodiments, movement and / or activation of at least one magnetic field source 114 may be controlled responsive to one or more of detected magnetic field strength and detected magnetic field direction, which may be detected by one or more magnetic field sensors 121.

[0062] In certain embodiments, a plurality of electrodes 172A-172C are arranged at different positions (i.e., spaced apart from one another) along the elongated body structure 150 near the proximal end 180 thereof. In certain embodiments, each electrode 172A-172C is generally tubular in shape and locally extends around substantially an entirety of an outer perimeter of the elongated body structure 150.

[0063] In certain embodiments, the magnetic field source(s) 114 and linear actuator 152 may be robotically controlled without user intervention to achieve a desired trajectory of the elongated body structure 150 for positioning one or more electrodes 172A-172C at desired location(s) within brain tissue 110.

[0064] A linear actuator 152 is provided to control advancement of the elongated body structure 150 into and within tissue 110 (e.g., brain tissue) of the human or other animal body. A data acquisition device 136 sends control inputs to a linear actuator driver 151 that supplies power to the linear actuator 152 which is coupled with the elongated body structure 150. Operation of the linear actuator 152 is controlled together with the at least one magnetic field source 114 to cause the elongated body structure 150 to move along a desired non-linear trajectory within the tissue 110. In certain embodiments, signals provided to and / or obtained from the linear actuator 152 may be indicative of advancement of the elongated body structure 150 into the tissue 110, and may be used (together with signals from a fiber optic shape sensor161 and associated FOSS driver / detector 160 as described herein) to determine position of the elongated body structure 152 within the tissue 110.

[0065] With continued reference to FIG. 1, in certain embodiments, position of the elongated body structure 150 of the surgical instrument within tissue 110 (e.g., brain tissue) may be estimated without continuous imaging techniques. In certain embodiments, one or more fiber optic shape sensors 161 may be provided in or on the elongated body structure 150 and inserted into brain tissue 110. Light signals may be supplied to a sensing optical fiber by a FOSS driver / detector 160 arranged external to the tissue of the human or other animal body 110. Reflected light signals received by the FOSS driver / detector 160 may be used to determine one or more of force, strain, or shape of the fiber optic shape sensor(s) 161 associated with the elongated body structure 150, and thereby used (e.g., in conjunction with signals provided to and / or received from the linear actuator 152) to determine orientation and position of the elongated body structure 150. In certain embodiments, FOSS sensors (e.g., one or more optical fibers with multiple sensing regions 164) may be secured to the elongated body structure 150 with a biodegradable polymer such as PEO or another adhesive or wax. In certain embodiments, fragile optical fibers of FOSS sensors 161 may be safeguarded by encasement in stress-dissipating Teflon or Nitinol tubes. In certain embodiments, temperature-induced reading variances may be mitigated through insulation and signal-processing compensation techniques. Implementing these strategies may significantly enhance robustness and accuracy of FOSS sensors 161, such as FBG or OFDR sensors.

[0066] In certain embodiments, a three-dimensional (3D) model of brain tissue (and / or other tissue) of a human or other animal body is generated before a steerable assembly as described herein (e.g., including an elongated body structure 150) is supplied to tissue 110 of the human or other animal body. Such a 3D model may be generated by any suitable imaging device 123, such as a MRI, CT, ultrasound, fluoroscopy, or other imaging device. The 3D model, optionally received via a network interface 144 and / or generated from 3D model input data 142 as part of a 3D model interaction subsystem 141, may be stored to memory 146 accessible to at least one processor 130, in preparation for receiving 3D trajectory information of a steerable assembly (including the elongated body structure 150) for superimposition onto the 3D model. The 3D model may be viewable via a display 148. The 3D trajectory information may be determined by directly by imaging, or inferentially from a detected length of insertion of the elongated body structure 150 into the tissue 110, in combination with a recorded directionality of a magnetic field applied (by magnetic effectors 112A, 112B) to a premagnetized material156 (e.g., proximate to tip portion 181) associated with the elongated body structure 150 that may be part of a surgical instrument.

[0067] In certain embodiments, recording of directionality of one or more magnetic fields supplied by one or more magnetic field sources 112A, 112B comprises recording control signals supplied motor drivers 116 coupled with the robotic manipulator 114 configured to adjust position of magnetic end effectors 112A, 112B configured to apply one or more magnetic fields to a premagnetized material 156 of the elongated body structure 150. Restated, the recording of directionality of the magnetic field may comprise recording control signals supplied to robot arm 114. In certain embodiments, recording of directionality of the magnetic field may comprise, or be supplemented by, collected signals received from one or more magnetic field sensors 121. In certain embodiments, one or more magnetic field sensors 121 may be positioned proximate to the tissue 110 into which the elongated body structure 150 is inserted.

[0068] In certain embodiments, the system 100 may be configured to receive signals for linear translation / insertion of an elongated body structure 150 (for determining insertion depth of the elongated body structure 150), receive signals for movement of a robotic actuator (for determining magnetic field direction), and process the signals for forwarding to a computer processor (e.g., 130) for superimposition of a 3D trajectory of the elongated body structure 150 on a previously generated 3D model of tissue 110 (e.g., brain tissue) into which the elongated body structure 150 is inserted. By superimposing FOSS sensor data onto pre-operative MRI, CT, and / or CAT scans of the brain, dynamic visualization (e.g., using display 148) of placement of an elongated body within brain tissue 110 is enabled.

[0069] In certain embodiments, a condition indicative of heart rate, respiration rate, and / or respiration amplitude of a human and / or animal body may be sensed (e.g., with chest sensors, respiration sensors, radar-based sensors, or the like) and responsive to the sensing, a 3D model of the body containing the tissue 110 (storable in memory 146) may be updated, and / or position of the magnetic end effector(s) 114 may be adjusted. In certain embodiments, the foregoing scheme may be used to update end effector position (e.g., maintain constant distance between the tissue 110 and the magnetic end effector(s) 114) so that a desired (e.g., constant) magnetic force is applied on the premagnetized material 156 associated with the elongated body structure 150.

[0070] In certain embodiments, a voltage source and / or electrical driver 170 (which may include one channel or multiple channels, each configured to drive a corresponding electrode)is coupled with one or more electrical conductors 170 extending in the elongated body structure 150 to transmit electrical signals to one or more electrodes 172A-172C that are externally accessible along an exterior of the elongated body structure 150 and arranged proximate to the distal end 180 thereof. When the elongated body structure is placed at a desired position within brain tissue 110, electrical signals may be emitted through the electrode(s) 172A-172C to interact with desired portions of brain tissue 110 (including, but not limited to, amygdalar subnuclei) to provide therapeutic effect. In certain embodiments, the electrical stimulation supplied by the electrode(s) 172A-172C to brain tissue 110 is provided to treat drug-resistant PTSD and / or other conditions.

[0071] As noted previously, a premagnetized material 156 (which may be arranged as a single premagnetized body, or arranged as multiple premagnetized bodies that are spaced apart or contacting one another) is associated with the elongated body structure at one or more locations proximate to a distal end 180 thereof. In certain embodiments, the premagnetized material 156 is arranged within the elongated body structure to permit the elongated body structure 150 to be steered to a desired location within brain tissue 110, but the premagnetized material 156 is configured to be removed from the elongated body structure 150 while the elongated body structure 150 remains within the brain tissue 111, such as to permit imaging (e.g., via MRI) of the brain tissue 111 with the elongated body structure 150 received therein. In certain embodiments, the premagnetized material 156 may be weakly adhered to an interior of the elongated body (e.g., with a biodegradable polymer such as polyethylene oxide (PEO), or another adhesive and / or wax material), and one or more tethers (e.g., wires and / or filaments) may be coupled with the premagnetized material 156 to permit the premagnetized material 156 to be extracted or otherwise removed from the elongated body structure 150 by pulling the premagnetized material 156 through a passage of the elongated body structure 150. In certain embodiments, premagnetized material 156 may be secured to an elongated body structure 150 using heat shrink tubing and biodegradable polymers. In certain embodiments, a premagnetized material 156 and a FOSS sensor 161 may be positioned sequentially within a single heat shrink tube that is inserted into a hollow tube or sheath that forms the elongated body structure 150.

[0072] As shown in FIG. 1, one or more additional sensors 134 (e.g., for sensing temperature, sensing pressure, capturing images, etc.) may be associated with the elongated body structure 150 to provide additional information useful for ascertaining position and / or controlling delivery of electrical stimulation.

[0073] In certain embodiments, the elongated body structure 150 may utilize a NeuroPace RNS tubular electrode device (1.27 mm OD, 0.4 mm ID, and typically utilizing a stylet for linear insertion) modified to receive both a FOSS sensor (fiber) 161 and one or more internal magnets (premagnetized material 156), with the FOSS sensor fiber and internal magnets being assembled using heat shrink tubing and secured within the lumen of the tubular electrode device using biodegradable polyethylene oxide (PEO). Preliminary phantom and cadaver studies have demonstrated that the resulting elongated body structure 150 retains sufficient stiffness for mechanical insertion while remaining flexible enough to enable magnetic steering. After the elongated body structure is accurately placed in tissue, the FOSS-magnet assembly may be removed by pulling on the heat shrink tubing once the PEO dissolves, leaving the implanted tubular electrode device in place for post-operative MRI and long-term therapy.

[0074] FIG. 2 is a perspective view of a robotic arm 214 incorporating magnets 213-1, 213- 2 (e.g., permanent magnets or electromagnets) to serve as an end effector 212 to effectuate movement of a steerable assembly including an elongated body structure incorporating a premagnetized material within tissue of a human or other animal body according to certain embodiments. In certain embodiments, the magnets 213-1, 213-2 may be, or may be controlled to be, of the same polarity or opposing polarities. The robotic arm 214 is mountable to a support surface 220 and includes multiple joints 225-229 to provide numerous degrees of freedom for movement of the robotic arm 214 relative to tissue (e.g., brain tissue) of a human or other animal body (not shown) in order to effectuate movement of an elongated body structure of a steerable assembly as described herein within the tissue.

[0075] FIG. 3 is a schematic side view illustration of a portion of a fiber Bragg grating (FBG) sensor 262 (representing one example of a fiber optic shape sensor) that may be utilized with components for determining position of a steerable assembly as described herein within tissue (e.g., brain tissue) of an animal body according to certain embodiments. The FBG sensor 262 is embodied in a sensing optical fiber 261 having a core 263 surrounded by cladding 265. A portion of the core 263 constitutes an index modulation region 264 in which an index of refraction of glass material of the core 263 periodically varies. When an input signal 266A (having a propagating core mode) is transmitted through the core 263 and reaches the index modulation region 264, one spectral portion of the input signal is reflected to produce a reflected signal 266C, while another spectral portion is transmitted through the index modulation region 264 to provide a transmitted signal 266B. The reflected signal 266C may be detected by a light detector associated with a FBG driver / detector unit (not shown), andanalyzed to determine one or more of force, strain, or shape experienced by the FBG sensor 262. In certain embodiments, one or more FBG sensors may be arranged in or on an elongated body structure of a steerable assembly, wherein an index modulation region may be provided proximate to a distal end of the elongated body structure.

[0076] As an alternative to using FBG sensors, OFDR sensors may be used in certain embodiments. Performance issues with OFDR often arise from complications within a tunable laser source (TLS) and the interferometer, including nonlinear tuning of the TLS and the polarization-induced fading in the interferometer. To enhance performance of OFDR, solutions like improving TLS tuning linearity, compensating for nonlinear phase noise, and employing polarization diversity detection have been explored. In certain embodiments, a frequencysampling method will be utilized, where sampling occurs at consistent frequency intervals, offering a robust solution for counteracting nonlinear tuning within the sensing range. This method, paired with random optical gratings by ultraviolet laser exposure, is anticipated to markedly boost the signal -to-noise ratio, thereby enhancing sensing accuracy.

[0077] FIG. 4 is a perspective view of robot arm 214 mounted on a rolling cart 220, with the robot arm 214 including first and second arms 215 A, 215B (forming a fork-like projection) that support opposing first and second permanent magnets 212A, 212B arranged to be positioned on either side of brain tissue 110 of a patient supported by a horizontal platform 109. FIG. 4 further shows a steerable assembly 262 extending through an incision 211 to be inserted into the brain tissue 110, with the steerable assembly 262 including an elongated body structure (e.g., a catheter) bearing at least one fiber optic shape sensor and at least one electrode to permit delivery of electrical stimulation to the brain tissue 110 according to one embodiment. At least one driving apparatus 260 may supply electrical signals to the electrode(s) and may also send / receive signals for operation of the at least one fiber optic shape sensor. FIG. 4 further includes two inset images of a display 248 showing side and top views of brain tissue with the elongated body structure 150 of a steerable assembly therein.

[0078] FIG. 5 shows an image of brain tissue at left, with a magnified portion at right showing a portion of the brain tissue 110 with a steerable assembly 150 having a curved (e.g., curved zig-zag) trajectory therein according to one embodiment. As shown, the steerable assembly 150 includes a generally conical tip 181 and four generally cylindrical electrodes 172A-172D that are spaced apart from one another and configured to deliver electrical stimulation to the brain tissue 110. A premagnetized material (e.g., 156 in FIG. 1) and a FOSS sensor fiber (e.g., 161 in FIG. 1) may be arranged within the steerable assembly 150. Thecurved zig-zag trajectory of the steerable assembly 150 shown in FIG. 5 is not attainable with an electrode device in the prior art utilizing conventional linear insertion methods.

[0079] Using COMSOL multiphysics simulations, the inventors have established the feasibility of deploying Neodymium Iron Boride (NeFeB) magnets, coated with biocompatible parylene C, for puncturing and navigating through brain tissues. The simulations confirm that magnets of sizes suitable to performance of the methods described herein can generate sufficient force for performing intricate intracranial operations. In certain embodiments, an elongated body (i.e., a lumen) of a steerable assembly includes a premagnetized material arranged therein (e.g., premagnetized material 156 within elongated body 150 in FIG. 1), optionally secured to the elongated body with a biodegradable polymer such as polyethylene oxide (PEO). In certain embodiments, external magnets (arranged outside a body of a subject to be treated, such as magnets 112A, 112B in FIG. 1 or 212A, 212B in FIG. 2) may be controlled with a UR30 robotic arm configured to carry a payload of 30 kg with a repeatability of 100 microns.

[0080] FIG. 6 is a plot of force versus displacement showing forces needed for puncturing and moving through brain tissue for lumens having diameters ranging from 7.5 to 100 microns. As shown, a large magnitude force is required to effectuate puncture (at displacement values roughly between 0.2 and 0.5 mm), then force is reduced for initial displacements after puncture, but force steadily increases as displacement is increased thereafter.

[0081] FIG. 7 is a plot of magnetic pulling force (in Nm) applied to two 15 kg cubic external magnetic on cylindrical internal magnets of diameters 0.5 to 1.5 mm at different distances ranging from 100 to 200 mm. As shown, pulling force increases with increasing internal magnet size, but decreases with increasing distance between internal and external magnets.

[0082] FIG. 8 is a hybrid point-to-point and path diagram for controlling a steerable assembly having an internal magnet using magnetic steering and avoiding back-tracking according to one embodiment. A reference path 201 is shown in dashed lines, with multiple points Pi, Pi-i, Pi, Pi+i, Pi+2, and Pnarranged thereon, wherein point Pi+2 coincides with a target point Ptarget. An actual path 202 traversed by a tip portion 181 of an elongated body structure (not shown) is depicted as a solid line. The tip portion 181 is subjected to magnetic steering using a system as described herein to extend through the target point Ptarget. In certain embodiments, the reference path 201 is predefined according to a surgical plan, and advancement of the tip portion 181 of an elongated body structure through brain tissue is motivated by combinedoperation of a linear actuator (e.g., 152 in FIG. 1) and a movable magnetic field source (e.g., robotic arm 114 and associated premagnetized materials 112A, 112B in FIG. 1).

[0083] FIG. 9 is a block diagram for a closed-loop control system for steering of an intracranial magnetically steerable assembly according to one embodiment. The closed-loop control system, which draws on nonholonomic system models, integrates feed-forward and feedback elements. Real-time FOSS sensor feedback may be used to guide adjustments that improve accuracy and safety of the steering system. According to the block diagram of FIG. 9, pre-planned trajectory is input in Cartesian coordinates, from which the control system calculates the desired state and control inputs. Real-time FOSS sensor data captures the pose of the elongated body structure within the brain tissue, feeding back into the control loop for continuous trajectory correction. FIG. 9 includes multiple functional blocks. At left, one block 302 includes trajectory transformation, from which a feedforward component block 304 is derived, wherein an output of the trajectory information block 302 (as well as output of a state transformation block 308) is supplied to a feedback component block 306. Outputs of the feedforward component block 304 and the feedback component block 306 utilized by inverse of input transformation block 301 that supplies an output signal to magnetic system block 312 according to which a magnetic steering system 314 (e.g., including magnetic field generating block 314 that cooperates with internal magnet-brain tissue interaction block 316), wherein optical frequency domain reflectometry (OFDR) localization block 318 (incorporating a fiber optic shape sensor) cooperates with various other blocks (e.g., the magnetic system block 314, the inverse of input transformation block 310, and the state transformation block 308).

[0084] A two-phase experimental verification of the 3D magnetic steering system is now described. The above-described closed-loop control system is evaluated within brain phantom tissues (i.e., materials simulating brain tissue) to define paths. Preliminary results for manipulating an elongated body (e.g., catheter) having a FOSS sensor and internal magnets through various curvature in two distinct phantom gels are shown in FIGS. 10 and 11, with movement of the elongated body being guided by robotic arm -manipulated external magnets, with FOSS feedback driving the control algorithm. FIG. 10 is a plot of path (Y mm vs. X mm) for manipulation of a catheter (exemplifying an elongated body structure) equipped with a premagnetized material (along an exterior of the catheter) through three different curvatures (10.2 mm, 20.3 mm, and 30.5 mm) in a stiff phantom gel, tracked using a fiber Bragg grating system. FIG. 11 is a plot of path (Y mm vs. X mm) for manipulation of the magnet-equipped catheter of FIG. 10 through three different curvatures in a soft phantom gel, tracked using afiber Bragg grating system. FIG. 11 also includes an inset view of an 8mm length distal tip portion of the magnet-equipped catheter, showing a premagnetized material embodied in three contacting tube-shaped bodies each having an outer diameter of 1 mm.

[0085] Further validation of the magnetic steering system may be obtained with experimentation. Trajectories may be planned based on pre-surgery MRI that visualizes both the brain’s vasculature as well as the target structures Amygdalar sub-nuclei are beyond the resolution of structural MRIs obtained at clinical-grade magnet strengths. Accordingly these sub-nuclei may be segmented based on non-linear registrations of atlases with individual cadaver structural MR sequences. Trajectories may be planned with two primary considerations: (i) implant configuration non-linearly contoured to the target structures; and (ii) avoidance of vascular contact both en-route to the target structures as well as within the target structures.

[0086] After forming a burr hole in the skull of a subject (e.g., a non-human (porcine) head or cadaver head for testing purposes), a steerable assembly including an elongated body structure equipped with a FOSS sensors and a magnet, may be carefully inserted and magnetically navigated to the target region within the brain using a combination of motorized pushing via a linear actuator and magnetic steering. For the implantation of amygdalar electrodes, the process will entail guiding from the cortical surface to the postero-lateral entry point of the amygdala; advancing in the sagittal plane towards the anterior amygdaloid area at the front of the amygdala; and finally, directing in the coronal plane to reach the central-medial amygdala (CMA) and the cortico-amygdaloid transition zone at the supero-medial aspect of the amygdala.

[0087] Interaction forces between the implanted elongated body structure and brain tissue may be recorded using a high-resolution load cell integrated into the elongated body structure insertion mechanism. The outcome of the steering process may be measured with respect to two benchmarks, namely: (1) post-surgery MRI to assess for vascular injury (as evidenced by contrast leakage outside the vasculature), and (2) post-surgery CT scans to verify position of the elongated body. Monitoring of the FOSS system may be performed at a 50-Hz frequency. One-tailed sample t-tests may be applied to the data to ensure that the mean tip placement error does not exceed 500 microns. A tip placement resolution of at least 500 microns at speeds of up to 5 mm per second may be attained.

[0088] FIG. 12 provides plots of force (g) versus time (sec) depicting penetration transients and cumulative drag forces on a 3-mm diameter catheter moved through 0.6 agarose gel(representing a phantom material for simulating brain tissue) by a motor-drive force gauge inserted at a rate of 0.33 mm per second, with a mean data plot presented along with upper and lower values of standard deviations of the data.

[0089] FIG. 13 provides plots of force (g) versus time (sec) depicting penetration transients and cumulative drag forces on a 3-mm diameter catheter moved through porcine brain tissue by a motor-drive force gauge inserted at a rate of 0.33 mm per second, with a mean data plot presented along with upper and lower values of standard deviations of the data.

[0090] FIG. 14 illustrates an experimental apparatus for steering an elongated body structure 150 with flexible magnets 156 attached thereto and including an electrode 172, the system including an external magnet 112 carried by a robotic arm 114 and a linear actuator 170 for advancement of the elongated body structure 150 within a phantom gel 109 arranged on a support surface 98. A FOSS (e.g., fiber Bragg grating) driver 160 is further provided to interact with a sensing fiber borne by the elongated body structure 150. An inset dashed-line rectangle at left shows a distal end portion of the elongated body structure 150.

[0091] FIG. 15A is a top plan view of the path of a magnetically steerable assembly 401 superimposed on a preoperative MRI / CT image of a cadaver brain 110, with FIGS. 15C and 15D providing rear elevational and left side elevational views, respectively, of the same items. FIG. 15B is a perspective view of the path of a magnetically steerable assembly 401 superimposed on a three-dimensional image of a cadaver head 110’. FIG. 16A is a top plan view of the path of another magnetically steerable assembly including FOSS sensors 401 superimposed on a preoperative MRI / CT image of a cadaver brain 110, with FIGS. 16C and 16D providing rear elevational and left side elevational views, respectively, of the same items. FIG. 16B is a perspective view of the path of a magnetically steerable assembly 401 superimposed on a three-dimensional image of a cadaver head 110’. In each of the foregoing figures, a liner actuator was used to push a steerable assembly while external magnets mounted to a robotic arm were used to pull and adjust directionality of the steerable assembly within brain tissue. An associated control system calculated required external magnet positions for each segment of the panned trajectory, and the robotic arm moved the external magnets accordingly to effectuate steering of the magnetically steerable assembly 401. Tracked shape and position of the magnetically steerable assemblies of FIGS. 15A to 16D demonstrate the capability of three-dimensional steering within brain tissue.

[0092] A physics-based model of the flexible elongated body structure (steerable assembly) was developed using the PyElastica simulation framework. Model parameters were calibratedusing experimental data from two configurations involving a clamped tubular elongated body structure under (i) gravity alone and (ii) combined gravity and magnetic field conditions. FIG. 18 is a plot of steerable assembly deflection in two dimensions according to PyElastica-based simulations measurements of steerable assembly deflection under gravity alone and under combined gravity plus magnetic field conditions. This model enables predictive simulation of elongate body structure deformation during insertion, informing control strategies and helping optimize magnet positioning for accurate steering.

[0093] FIG. 19 is a schematic diagram of a generalized representation of a computer system 500 that can be included as one or more components of a system or method utilizing magnetic steering and linear actuation for placement one or more electrodes within brain tissue of a subject to permit delivery of electrical stimulation to the brain tissue according to one or more embodiments. The computer system 500 may be adapted to execute instructions from a computer-readable medium to perform these and / or any of the functions or processing described herein.

[0094] The computer system 500 may include a set of instructions that may be executed to program and configure programmable digital signal processing circuits for supporting scaling of supported communications services. The computer system 500 may be connected (e.g., networked) to other machines in a local area network (LAN), an intranet, an extranet, or the Internet. While only a single device is illustrated, the term "device" shall also be taken to include any collection of devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. The computer system 500 may be a circuit or circuits included in an electronic board or card, such as a printed circuit board (PCB), a server, a personal computer, a desktop computer, a laptop computer, a personal digital assistant (PDA), a computing pad, a mobile device, or any other device, and may represent, for example, a server or a user's computer.

[0095] The computer system 500 in this embodiment includes a processing device or processor 502, a main memory 504 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM), such as synchronous DRAM (SDRAM), etc.), and a static memory 506 (e.g., flash memory, static random access memory (SRAM), etc.), which may communicate with each other via a data bus 508. Alternatively, the processing device 502 may be connected to the main memory 504 and / or static memory 506 directly or via some other connectivity means. The processing device 502 may be a controller, and the main memory 504 or static memory 506 may be any type of memory.

[0096] The processing device 502 represents one or more general -purpose processing devices, such as a microprocessor, central processing unit (CPU), or the like. In certain embodiments, the processing device 502 may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor implementing other instruction sets, or other processors implementing a combination of instruction sets. The processing device 502 is configured to execute processing logic in instructions for performing the operations and steps discussed herein.

[0097] The computer system 500 may further include a network interface device 510. The computer system 500 may additionally include at least one input 512, configured to receive input and selections to be communicated to the computer system 500 when executing instructions. The computer system 500 also may include an output 514, including but not limited to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), an alphanumeric input device (e.g., a keyboard), and / or a cursor control device (e.g., a mouse).

[0098] The computer system 500 may or may not include a data storage device that includes instructions 516 stored in a computer readable medium 518. The instructions 516 may also reside, completely or at least partially, within the main memory 504 and / or within the processing device 502 during execution thereof by the computer system 500, the main memory 504 and the processing device 502 also constituting computer readable medium. The instructions 516 may further be transmitted or received over a network 520 via the network interface device 510.

[0099] While the computer readable medium 518 is shown in an embodiment to be a single medium, the term "computer-readable medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) that store the one or more sets of instructions. The term "computer readable medium" shall also be taken to include any medium that is capable of storing, encoding, or carrying a set of instructions for execution by the processing device and that cause the processing device to perform any one or more of the methodologies of the embodiments disclosed herein. The term "computer readable medium" shall accordingly be taken to include, but not be limited to, solid- state memories, an optical medium, and / or a magnetic medium.

[0100] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an,"and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0101] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0102] It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0103] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0104] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

[0105] Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.

Claims

ClaimsWhat is claimed is:

1. A system for placement of at least one electrode within brain tissue to enable delivery of electrical stimulation, the system comprising: at least one magnetic field source; a steerable assembly that comprises: an elongated body structure having a proximal end and a distal end, the at least one electrode arranged along an exterior of the elongated body structure, a premagnetized material arranged closer to a distal end than to a proximal end of the elongated body structure, and fiber optic shape sensor within the elongated body structure; and a linear actuator coupled to the elongated body structure at a position closer to the proximal end than to the distal end of the elongated body structure, the linear actuator being configured to advance at least a portion of the elongated body structure within the brain tissue; wherein the at least one magnetic field source is configured to interact with the premagnetized material to effectuate steering of the distal end of the elongated body structure when the distal end is arranged within the brain tissue; and wherein the at least one electrode is configured to be coupled to a voltage source to permit electrical signals to be delivered through the at least one electrode to one or more areas of the brain tissue.

2. The system of claim 1, wherein the at least one electrode comprises a plurality of electrodes arranged at different positions between the proximal end and the distal end of the elongated body structure.

3. The system of claim 2, wherein each electrode of the plurality of electrodes is generally tubular in shape and locally extends around substantially an entirety of an outer perimeter of the elongated body structure.

4. The system of claim 1, further comprising at least one robotic arm configured to move the at least one magnetic field source.

5. The system of claim 1, wherein the premagnetized material comprises at least one of a permanent magnet, a ferromagnetic material, and an electromagnet.

6. The system of claim 1, wherein the premagnetized material is arranged within an interior of the elongated body structure.

7. The system of any one of claims 1 to 6, wherein the premagnetized material is configured to be removed from the interior of the elongated body structure while the at least a portion of the elongated body structure is arranged within the brain tissue.

8. The system of any one of claims 1 to 6, wherein the fiber optic shape sensor comprises one or more optical frequency domain reflectometry (OFDR) sensors.

9. The system of any one of claims 1 to 6, wherein the fiber optic shape sensor comprises one or more fiber Bragg grating (FBG) sensors.

10. The system of any one of claims 1 to 6, further comprising at least one processor configured to control operation of at least one magnetic field source, the steerable assembly, and the linear actuator.

11. The system of claim 10, further comprising the voltage source, wherein the at least one processor is further configured to control the voltage source to deliver electrical signals through the at least one electrode to one or more areas of the brain tissue.

12. The system of claim 10, further comprising one or more magnetic field sensors, wherein the at least one processor is configured to control movement and / or activation of the at least one magnetic field source responsive to outputs of the one or more magnetic field sensors.

13. The system of claim 10, wherein the at least one processor is configured to control the at least one magnetic field source and the linear actuator without user intervention.

14. The system of any one of claims 1 to 6, further comprising a user input device controllable by user manipulation, wherein the magnetic field source and the linear actuator are configured to be operated responsive to outputs of the user input device.

15. A method for delivering electrical stimulation to brain tissue using the system of claim 1, the method comprising: moving the at least one magnetic field source to effectuate steering of the distal end of the elongated body structure and advancing the elongated body structure within the brain tissue using the linear actuator to position the one or more electrodes at one or more desired locations within the brain tissue; and operating the voltage source to deliver electrical signals through the one or more electrodes to interact with portions of the brain tissue.

16. The method of claim 15, wherein the operating of the voltage source to deliver electrical signals through the one or more electrodes to interact with portions of the brain tissue is configured to treat post-traumatic stress disorders.

17. The method of claim 15, wherein the operating of the voltage source to deliver electrical signals through the one or more electrodes to interact with portions of the brain tissue is configured to treat drug-resistant epilepsy.

18. The method of claim 15, wherein the one or more electrodes comprises multiple electrodes, and the operating of the voltage source to deliver electrical signals through the one or more electrodes comprises delivering independent electrical signals to individual electrodes of the multiple electrodes.

19. The method of claim 15, wherein the moving of the at least one magnetic field source comprises moving the at least one magnetic field source using at least one robotic arm.

20. The method of claim 15, wherein one or more magnetic field sensors are provided, and wherein the method further comprises controlling movement and / or activation of the at least one magnetic field source responsive to outputs of the one or more magnetic field sensors.

21. The method of claim 20, further comprising utilizing three-dimensional trajectory information and a three-dimensional model of the brain tissue to control movement the at least one magnetic field source and control advancement of the elongated body structure within the brain tissue.

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