Cranially mounted implantable neurostimulator housing and cradle thereof

Abstract

Provided herein are housings and cradles for cranially-mounted implantable neurostimulators (INS). The INS housing can include an external surface having a curved profile that corresponds to the curvature of a human skull. The INS housing may include a lead connection port and one or more attachment portions configured to enclose a control circuit for neurostimulation. The INS may be contained within a cradle configured to be implanted in the skull. Due to the low profile of the INS housing, whether implanted in the skull within the cradle or itself implanted to the skull, may not protrude from the surface of the skull and thus may not introduce additional pressure at the skull.

Description

CRANIALLY MOUNTED IMPLANTABLE NEUROSTIMULATOR HOUSING ANDCRADLE THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 588,666, filed October 6, 2023, the entire contents of which are incorporated by reference herein in their entirety.FIELD

[0002] This disclosure relates generally to implantable neurostimulators, and more specifically to housings of and cradles for cranially mounted implantable neurostimulators for brain neurostimulation.BACKGROUND

[0003] Deep brain stimulation (DBS) is a neurostimulation therapy that can be used to treat neurodegenerative disorders such as epilepsy and Parkinson’s disease (PD). In DBS, an artificial electrical current is provided to specific parts of the brain to stimulate neurons, which in turn eases the symptoms experienced in different brain conditions. For example, in patients with PD, high-frequency stimulation is provided to regions of the basal ganglia (e.g., the subthalamic nucleus (STN) or internal globus pallidus (GPi)) to correct imbalances in excitation-inhibition in the basal ganglia circuit. DBS can ease motor symptoms experienced in PD and decrease the need for pharmacological treatment.

[0004] Deep brain stimulation systems, otherwise referred to herein as brain neurostimulation systems commonly include one or more stimulation leads (e.g., comprising electrodes) implanted in the brain and a pulse generator (e.g., stimulator battery) implanted in the upper chest of the patient. One or more small incisions are made in the scalp of a patient, followed by one or more small openings in the skull that allow for lead implantation in the brain. In addition, a small incision is made in the upper chest to create a soft tissue pocket for the pulse generator. The stimulation leads are connected to the pulse generator, for example, using extension wires tunneled underneath the skin between the stimulation leads extending from the skull and the pulse generator in the upper chest. However, these extension leads can shift, causing pain and discomfort for the patient. Additionally, the extension leads may loosen, detach from the pulse generator, or break, each of which require subsequent surgical procedures to fix, reattach, or replace the leads. Additional surgical procedures can increasethe risk of intraoperative and / or postoperative surgical complications, such as infection, bleeding, swelling, and in more severe cases, coma, sepsis, and stroke. Moreover, implanting the stimulation leads and the pulse generator requires preparation of at least two surgical sites (e.g., the upper chest and one or more sites on the skull), and each of the procedures are typically executed individually in separate visits, which is a source of inefficiency in the surgical suite that is also accommodated by increased risk of surgical complications (i.e., due to the number of procedures).SUMMARY

[0005] Described herein are brain neurostimulation systems configured to be implanted in the skull of a patient and methods of use thereof. The neurostimulation systems can include a cranially mounted implantable neurostimulator (INS), otherwise referred to herein as a deep brain stimulator (DBS) or implantable pulse generator (IPG), comprising a housing (e.g., an INS housing). The INS (e.g., the INS housing) may comprise an external surface having a sleek, curved profile that mimics the curvature of a human skull. Thus, when implanted, the external surface of the INS may be substantially flush with the surface of the skull, thereby introducing minimal, if any, visual indication of the implanted neurostimulation system underneath the scalp, and also limiting any pressure on the scalp at the implant site. The INS (e.g., the INS housing) may itself be implanted into the skull, or in some instances, a cradle configured to receive the INS may be implanted into the skull. By implanting a cradle that receives the INS, future replacement of the INS can be simple and necessitate minimal surgical intervention. The INS housing and cradle may have substantially the same thickness profile as the skull, thereby introducing minimal pressure to the scalp and brain once implanted. Moreover, the INS described herein may be rechargeable yet maintain the low profile described herein by introducing an external coil for charging and communication, the dimensions of which can fit seamlessly between the skull and scalp and again introduce minimal pressure to the scalp.

[0006] In some embodiments, an implantable neurostimulator (INS) housing is provided, comprising: a lead connection port configured to receive one or more leads of an implantable neurostimulator; and a first enclosure portion and a second enclosure portion configured to attach to the first enclosure portion to enclose a control circuit for controlling brain neurostimulation, wherein at least one of the first enclosure portion and the second enclosure portion comprises an external surface having a curved profile corresponding to a curvature of a human skull.

[0007] In some embodiments, a method for implanting an implantable neurostimulator (INS) in a human skull is provided, comprising: removing a portion of the human skull to create an opening in the human skull sized to receive an INS housing; and inserting the INS housing into the opening in the human skull such that an external surface of the INS housing is flush with a surface of the human skull.

[0008] In some embodiments, an implantable neurostimulation system is provided, comprising: an implantable neurostimulator (INS) comprising an INS housing configured to enclose a control circuit for controlling brain neurostimulation; and a cradle configured to be implanted in an opening in a human skull and to receive the INS housing.

[0009] In some embodiments, a method for implanting an implantable neurostimulator (INS) in a human skull is provided, comprising: removing a portion of the human skull to create an opening in the human skull sized to receive a cradle for retaining an INS; and implanting the cradle in the opening in the human skull such that an external surface of the INS is flush with a surface of the human skull.

[0010] In some embodiments, a method for replacing an implantable neurostimulator (INS) implanted in the human skull is provided, comprising: removing the INS from a cradle implanted in the human skull; disconnecting one or more leads implanted in brain tissue from the INS; electrically connecting the one or more leads to a replacement INS; and inserting the replacement INS into the cradle implanted in the human skull.

[0011] In some embodiments, a method for performing an imaging procedure on a human having an implantable neurostimulator (INS) implanted in the skull of the human is provided, comprising: removing the INS from a cradle implanted in the human skull; disconnecting one or more leads implanted in brain tissue from the INS; performing the imaging procedure on the human; reconnecting the one or more leads implanted in the brain tissue to the INS; and reinserting the INS into the cradle implanted in the human skull.BRIEF DESCRIPTION OF THE FIGURES

[0012] Various aspects of the disclosed systems and methods are set forth with particularity in the appended claims. A better understanding of the features and advantages of the disclosed systems and methods will be obtained by reference to the detailed description of illustrative embodiments and the accompanying drawings.

[0013] FIG. 1A illustrates a partially transparent prospective view of an implantable neurostimulation system comprising an implantable neurostimulator (INS) disposed in a cradle, in accordance with some embodiments.

[0014] FIG. IB illustrates a prospective view of the implantable neurostimulation system, in accordance with some embodiments.

[0015] FIG. 1C illustrates a partially transparent, partial top view of the implantable neurostimulation system, in accordance with some embodiments.

[0016] FIG. ID illustrates a cross-sectional side view of the implantable neurostimulation system, in accordance with some embodiments.

[0017] FIG. IE illustrates a partially transparent prospective view of the implantable neurostimulation system with the INS detached from the cradle, in accordance with some embodiments.

[0018] FIG. IF illustrates a prospective view of the implantable neurostimulation system with the INS detached the cradle, in accordance with some embodiments.

[0019] FIG. 1G illustrates a cross-sectional view of the implantable neurostimulation system with a hollow INS housing, in accordance with some embodiments.

[0020] FIG. 1H illustrates a close-up, partial cross-sectional view of the hollow INS housing, in accordance with some embodiments.

[0021] FIG. II illustrates an exploded view of the implantable neurostimulation system, in accordance with some embodiments.

[0022] FIG. 2A illustrates a bottom view of an implantable neurostimulation system comprising an INS and a cradle with openings on a bottom surface of the cradle, in accordance with some embodiments.

[0023] FIG. 2B illustrates a perspective view of the implantable neurostimulation system comprising the INS and cradle with openings on the bottom surface, in accordance with some embodiments.

[0024] FIG. 3 illustrates a perspective view of an implantable neurostimulation system that does not comprise a cradle, in accordance with some embodiments.

[0025] FIG. 4 illustrates an example neurostimulation system implanted in the skull of a patient, in accordance with some embodiments.DETAILED DESCRIPTION

[0026] Described herein are cranially mounted neurostimulation systems for stimulation of the brain. Methods of use, including methods of assembling the neurostimulation systems, methods of implanting the neurostimulation systems in the skull, methods of stimulating using the neurostimulation systems, methods of replacing implanted neurostimulation systems, and methods of performing imaging procedures (such as magnetic resonanceimaging) on a human having an implanted neurostimulator are also described herein. The neurostimulation systems provided herein comprise a cranially mounted implantable neurostimulator (INS) (otherwise referred to as a deep brain stimulator (DBS) or implantable pulse generator (IPG)) comprising an INS housing that encloses internal control circuitry for stimulation. The INS (e.g., the INS housing) can comprise an external surface having a curved profile that corresponds with the curvature of the skull, therefore limiting protrusion of the INS from the skull when implanted and minimizing pressure at the implant site. The INS may comprise an external coil for charging and communication that also comprises the curved profile mimicking that of the skull. The neurostimulation system may in some instances comprise a cradle configured to receive the INS. The cradle may be implanted into the skull such that later replacement of the INS necessitates minimal surgical intervention without any additional bone removal. Furthermore, the thickness profile of the INS housing (and cradle) may not exceed that of the skull thickness, thereby limiting pressure on the brain and the scalp.

[0027] The following disclosure describes features of cranially mounted brain neurostimulation systems with respect to a first exemplary system comprising an INS and a cradle, a second exemplary system comprising a different cradle, and a third exemplary system that does not comprise a cradle. The description focuses first on features of the INS housing, followed by features of the cradle and the relationship between the cradle and the INS housing, before describing various features that can be included in the implantable neurostimulator itself. Within the descriptions of the various exemplary systems, methods of assembling, implanting, stimulating brain tissue, and / or replacing the neurostimulation systems are also described.

[0028] FIGS. 1A-1I illustrate an implantable neurostimulation system 100 comprising an implantable neurostimulator (INS) housing 102 and a cradle 104. The INS housing 102 may be configured to enclose a control circuit for controlling brain neurostimulation, such as control circuit 140 illustrated in FIG. II. The cradle 104 may be configured to be implanted in an opening in a human skull and may receive the INS housing 102, as illustrated in the Figures.

[0029] Although not explicitly stated, it is to be understood that various features of the exemplary neurostimulation systems, although described in some instances with respect to a particular system (e.g., neurostimulation system 100 illustrated in FIGS. 1A-1I), may apply to and be reasonably incorporated in other neurostimulation systems described herein unless explicitly stated otherwise. For example, absent an alternative indication, features of INShousing 102 and cradle 104 are understood to be encompassed by INS housing 202 and cradle 204 of neurostimulation system 200. Moreover, combinations of features described with respect to particular embodiments of a neurostimulation system may be reasonably combined unless explicitly stated otherwise.Implantable Neurostimulator (INS) Housing

[0030] INS housing 102 may comprise an external surface having a curved profde corresponding to a curvature of the human skull. For example, the curved profde of the external surface may comprise a constant spherical radius, a plurality of curvatures, or one or more non-uniform curvatures. Each curvature of the external surface may comprise one or more radii. For example, with respect to the coordinate systems illustrated in FIGS. 1A-1B, the curved profde may comprise a first curvature in the X-Z plane, and a second curvature in the Z-Y plane. The first curvature and the second curvature may comprise radii that are substantially the same, or the radii may be different. In some embodiments, the curved profde of the external surface may comprise a plurality of curvatures with varying radii in a first plane (e.g., the X-Z plane and / or the Z-Y plane), and a curvature in a second plane (e.g., the remaining X-Z plane and / or Z-Y plane). The radius of the curvature in the second plane may be substantially the same as the radius of a curvature in the first plane, or the radius may be different from that of the radii of curvatures in the first plane.

[0031] In some embodiments, a radius of the curved profde of the external surface (e.g., a radius of one or more curvatures of the curved profde) may be between about 80 mm and 140 mm. For example, the curved profde of the external surface may comprise a radius between 80-120 mm, 80-100 mm, 100-140 mm, 100-120 mm, or 120-140 mm. In some embodiments, a radius of the curved profde of the external surface may be greater than or equal to about 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, or 130 mm. In some embodiments, a radius of the curved profde of the external surface may be less than or equal to about 140 mm, 130 mm, 120 mm, 110 mm, 100 mm, or 90 mm.

[0032] In some embodiments, the curved profde of the external surface of the INS housing 102 may be based on anatomical measurements. For example, the curved profde of the external surface of the INS housing 102 may be determined based on various dimensions (e.g., radii and / or curvature) of the skull. More specifically, measurements of a region of the skull that is intended for INS implantation may be used to inform the curved profde of the INS housing 102. The intended implantation region may, for example, be the right parietal region or the left parietal region. The anatomical measurements may be aggregated from aproprietary dataset comprising skull measurements of a representative population for brain neurostimulators. For example, the representative population may comprise primarily adult males and females with skulls ranging in size from the 5thto the 95thpercentile.

[0033] In any instance, when implanted in the skull, the INS housing 102 may be substantially flush with the skull. In other words, the INS housing 102 may not protrude from the surface of the skull. In this manner, pressure on the scalp, skull, and brain at or around the implant site may be minimized. Also, following the implantation procedure, any indication of the implanted neurostimulation system in the skull may not be noticeable.

[0034] The INS housing 102 may comprise a first enclosure portion and a second enclosure portion configured to attach to the first enclosure portion to enclose a control circuit that controls brain neurostimulation. At least one of the first enclosure portion and the second enclosure portion may comprise the external surface having a curved profile that corresponds to curvature of the human skull, as described above. For example, FIG. II illustrates an exploded view of an implantable neurostimulation system that comprises a first enclosure portion 102a and a second enclosure portion 102b. When attached, the first enclosure portion 102a and the second enclosure portion 102b may enclose a control circuit 140 and a power source 142. The first enclosure portion 102a may be hermetically sealed with second enclosure portion 102b to enclose the internal components, such as the control circuit 140. For example, the first enclosure portion and the second enclosure portion may be welded (e.g., laser beam welded, friction stir welded, etc.) to irreversibly seal the enclosure portions together and contain the internal components within the INS housing 102. In this manner, it can be ensured that any internal electrical components within INS housing 102 do not unintentionally come into contact with fluids, tissue, etc. at any time during or after implantation of the neurostimulation system 100.

[0035] The first enclosure portion and second enclosure portion may attach in various configurations. For example, the first enclosure portion 102a may be a top (or cover), and the second enclosure portion 102b may be a bottom (or base), such that the internal circuitry components are placed on top of (or within a receptacle of) the second enclosure portion 102b and covered by the first enclosure portion 102a. In this example, a bottom surface of the first enclosure portion 102a may be configured to attach (e.g., be welded to) atop surface of the second enclosure portion 102b. Moreover, a top surface of the first enclosure portion may comprise the external surface having the curved profile corresponding to the curvature of the human skull.

[0036] In another example, the first enclosure portion may be a first side portion (e.g., a left or front side portion), and the second enclosure portion may be a second side portion (e.g., a corresponding right or back side portion), such that the internal circuitry components are placed within a receptacle of each of the first and the second enclosure portions. In this example, a side surface of the first enclosure portion may be configured to attach to (e.g., be welded to) a side surface of the second enclosure portion. Moreover, each of the first enclosure portion and the second enclosure portion may comprise at least a portion of the external surface having the curved profile corresponding to the curvature of the human skull. The first enclosure portion and the second enclosure portion may be symmetric and uniformly sized, or in some embodiments, may comprise differently shaped bodies that together are configured to enclose the control circuit 140. In some embodiments, the INS housing 102 may comprise more than two enclosure portions that are configured to enclose at least the control circuit 140, such as 3, 4, 5 or more enclosure portions.

[0037] In some embodiments, the implantable neurostimulation system 100 may comprise one or more internal securing members configured to secure the control circuit 140 and / or power source 142 within the INS housing 102. For example, FIG. 1G-1I illustrate one or more posts 138 extending from an inner surface of the INS housing 102 that can be used to position and / or secure the control circuit and / or power source 142 within the INS housing 102. The posts 138 may extend from an inner top surface, bottom surface, side surface, etc. of INS housing 102. The system 100 may comprise one or more fasteners 136 configured to receive or be received by the one or more posts 138. For example, as demonstrated by the exploded view of system 100 in FIG. II, the one or more fasteners 136 may be disposed beneath the control circuit 140 and power source 142, such that, when enclosed, one or more posts 138 extending from the inner top surface of INS housing 102 (e.g., a first enclosure portion 102a) may be fastened to the fasteners 136 to secure the internal components. The opposite scenario is also envisioned, in which the posts 138 extend from a bottom surface of the INS housing 102 (e.g., a second enclosure portion 102b), and once the control circuit 140 and power source 142 are appropriately positioned over the INS housing 102, the one or more fasteners 136 can be fastened to the one or more posts 138 to secure the internal components. The aforementioned mechanisms by which the control circuit 140 and / or power source 142 of the implantable neurostimulation system 100 can be secured are not intended to be limiting, and alternative means of doing so will be understood by one of ordinary skill in the art.

[0038] The INS housing 102 may comprise a lead connection port 106 configured to receive one or more leads of the INS system 100. In some embodiments, the lead connectionport 106 is contained within a header portion 110 (otherwise referred to herein as a header). As illustrated at least in FIG. 1A, the header 110 may contain a lead connector 108 that is configured to facilitate electrical contact between one or more leads inserted into the lead connector 108 and the internal components of the INS (e.g., the circuit board 140). The lead connection port 106 may be oriented within INS housing 102 such that the leads when connected to the lead connection port 106 do not introduce any additional protrusions from the implant site. For example, as shown at least in FIGS. 1E-1F, the lead connection port 106 may be oriented at an edge of the INS housing 102. In some embodiments, the lead connection port 106 may be oriented on a side of the INS housing 102 adjacent to the top external surface of the INS housing 102. In either instance, leads connected to the lead connection port 106 can exit the INS housing 102 and be tunneled alongside the INS housing 102 between the skull and the scalp to the location (e.g., a burr hole) at which the leads can be implanted through the skull and into the brain. Alternative arrangements of the connection between the leads and lead connector 108 will be described in greater detail below with respect to FIGS. 2A-2B.

[0039] The lead connector 108 may be disposed at an angle within the header 110, the angle dependent at least on the location of lead connection port 106 on the surface of the housing 102. As shown in FIG. ID, in the instance the lead connection port 106 is at an upper edge of the header 110, the lead connector 108 may be disposed within the header 110 at an angle between the lead connection port 106 and a coupling portion within header 110 that couples the electrical contacts of lead connector 108 to the internal components of the INS (e.g., the control circuit 140). The lead connector may comprise seals that prevent crosstalk between electrical contacts and isolate the electrical contacts from contact with bodily fluids. Alternative arrangements of the lead connection port 106 on the surface of INS housing 102 may necessitate an alternative arrangement of lead connector 108 within header 110, as will be understood by one of ordinary skill in the art.

[0040] The header 110 may comprise an external surface having a curved profile that comprises one or more features described herein with respect to the curved profile of the external surface of INS housing 102. For example, the curved profile of the external surface of the header 106 may be substantially the same as that which is described herein with respect to the curved profile of INS housing 102. Thus, the curved profile of the external surface of header 106 may otherwise be viewed as an extension of the curved profile of the external surface of INS housing 102.

[0041] In some embodiments, INS housing 102 may comprise a set screw block 112 that protrudes from INS housing 102 and can be inserted into a corresponding receptacle 124 in header 110. The set screw block 112 may capture a proximal end of the lead. In an alternative embodiments, header 110 may comprise a set screw block configured to be received by a corresponding receptacle in INS housing 102. Attachment between the set screw block 112 of INS housing 102 and the receptacle 124 of header 110 may be via a press-fit, slip-fit, threaded connection, and / or using additional connecting components, such as pins, screws, etc. For example, FIG. ID illustrates a cross-sectional view of the receptacle 124 of header 110 in which a screw 126 is used to secure the set screw block 112 within the receptacle 124. The screw 126 may additionally or alternatively secure the lead in place.

[0042] The INS housing 102 may comprise one or more biocompatible materials. In some embodiments, the one or more materials of the INS housing 102 may be conductive or non-conductive. For example, the INS housing 102 may comprise titanium or an alloy thereof. In some embodiments, the INS housing 102 additionally or alternatively comprises medical-grade stainless steel and / or one or more biocompatible materials (e.g., polypropylene, polyethylene, polyether ether ketone (PEEK), polycarbonate (PC), polyphenylsulfone (PPSU), Polyethylene terephthalate (PET), etc.).

[0043] As shown in FIGS. 1A-1F, the shape of INS housing 102 may comprise an obround profile that can be defined by a pair of semicircular regions connected by a pair of straight regions. In some embodiments, the shape of INS housing 102 may alternatively comprise an oblong, round, ovular, or other profile defined by one or more circular, semicircular, or otherwise curved regions. In this manner, preparation of the implantation site can be simplified, in that one or more round burr holes can be drilled into the skull, and in the instance two or more burr holes are drilled into the skull, the central portion connecting the burr holes can be removed by cutting in a linear fashion between edges of the burr holes. In some embodiments, the shape of INS housing 102 may comprise a square, triangular, rectangular, or other polygonal profile. In any instance, substantially all of the bone at the implant site can be removed with a saw tool that can cut the bone according to the curved profile of the INS housing 102.

[0044] In some embodiments, a first dimension (e.g., a length) of the INS housing 102 may be between about 30 mm and 50 mm. The length of the INS housing 102 may be defined as the horizontal distance (e.g., along the X-axis in FIGS. 1A-1B) between a first side of the INS housing 102 and an opposite second side of the INS housing 102. In some embodiments, the length of INS housing 102 may be greater than or equal to 30 mm, 32 mm, 34 mm, 36mm, 38 mm, 40 mm, 42 mm, 44 mm, 46 mm, or 48 mm. In some embodiments, the length of INS housing 102 may be less than or equal to 50 mm, 48 mm, 46 mm, 44 mm, 42 mm, 40 mm, 38 mm, 36 mm, 34 mm, or 32 mm.

[0045] In some embodiments, a second dimension (e.g., a width) of the INS housing 102 may be between about 20 mm and 40 mm. The width of the INS housing 102 may be defined as the vertical distance (e.g., along the Y-axis in FIGS. 1A-1B) between a first side of the INS housing 102 and an opposite second side of the INS housing 102. In some embodiments, the width of INS housing 102 may be greater than or equal to 20 mm, 22 mm, 24 mm, 26 mm, 28 mm, 30 mm, 32 mm, 34 mm, 36 mm, or 38 mm. In some embodiments, the width of INS housing 102 may be less than or equal to 40 mm, 38 mm, 36 mm, 34 mm, 32 mm, 30 mm, 28 mm, 26 mm, 24 mm, or 22 mm.

[0046] The INS housing 102 may comprise a thickness that is about the same as or less than the thickness of a human skull. The thickness of the INS housing 102 may be defined as a dimension in the Z-direction of the coordinate system illustrated in FIGS. 1A-1B. In the instance the external surface of the INS housing 102 comprises a curved profile, the thickness may be defined as the distance between the apex of the curved external surface and the opposite surface of the INS housing 102. In some embodiments, the thickness of INS housing 102 may be uniform or non-uniform throughout the body of the housing. In some embodiments, the thickness of the INS housing 102 may be between about 6 mm and 14 mm. For example, the thickness of the INS housing 102 may be greater than or equal to about 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, or 13.5 mm. In some embodiments, the thickness of the INS housing 102 may be less than or equal to about 14 mm, 13.5 mm, 13 mm, 12.5 mm, 12 mm, 11.5 mm, 11 mm, 10.5 mm, 10 mm, 9.5 mm, 9 mm, 8.5 mm, 8 mm, 7.5 mm, 7 mm, or 6.5 mm. In a similar manner as the curved profile of the external surface of the INS housing 102, the thickness dimension of the INS housing 102 may be based on anatomical measurements of human skulls (e.g., thickness dimensions of human skulls).

[0047] In some embodiments, when inserted to the skull at the implant site, the INS housing 102 may not protrude from the skull into the scalp. In some embodiments, the INS housing 102 may protrude less than or equal to a threshold distance from the surface of the scalp. For example, the INS housing 102 may extend no more than 5 mm, 4 mm, 3 mm, 2.5 mm, 2 mm 1.5 mm, 1 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.25 mm, 0.2 mm, 0.15 mm, 0.1 mm, or less from the external surface of the skull. In some embodiments, the anatomical measurement data may inform the upper threshold or limit for the thickness of the INShousing. Thus, the INS systems described herein may achieve full functionality of a brain stimulation system within a compact space limited not only by this threshold for thickness but also by the aforementioned shape and size requirements of the INS.

[0048] The neurostimulation system 100 may comprise a coil housing 120 containing one or more inductive coils 122. At least a portion of coil housing 120 may be connected to and extend from INS housing 102. The coil housing 120 may be mechanically and electrically coupled to the INS housing 102. For example, the coil housing 120 may be adhered to an external surface of the INS housing 102 using a silicone adhesive. Additionally, the coil housing 120 may be electrically coupled to the INS housing 102 and / or the header 110 via one or more electrical contacts (e.g., pins). The coil housing 120 may comprise an external surface having a curved profde that comprises one or more features described herein with respect to the curved profde of the external surface of INS housing 102. For example, the curved profde of the external surface of the coil housing 120 may be based on anatomical measurements and / or may comprise one or more uniform or non-uniform curvatures. In some embodiments, the curved profde of the external surface of coil housing 120 may be substantially the same as that which is described herein with respect to the curved profde of INS housing 102. Thus, the curved profde of the external surface of coil housing 120 may otherwise be viewed as an extension of the curved profde of the external surface of INS housing 102. In this manner, the coil housing 120 may not introduce any additional pressure at the implant site and may fit seamlessly between the scalp and the skull without introducing any visual indication of the implant underneath the scalp.

[0049] Although implantable neurostimulation system 100 as illustrated comprises a cradle 104, which will be described in greater detail below, the cradle 104 may be optional. In other words, the implantable neurostimulation system described herein may be “cradleless.” FIG. 3 illustrates a cradle-less implantable neurostimulation system 300. Aside from cradle 104, system 300 may comprise any one or more features described herein with respect to neurostimulation system 100. For example, INS housing 302 may comprise a first enclosure portion and a second enclosure portion. Neurostimulation system 300 may comprise a coil housing 320 containing a radio frequency coil.

[0050] Because the neurostimulation system 300 does not comprise a cradle configured to be attached to the skull and receive the INS housing, the INS housing 302 may differ from INS housing 102 in that the INS housing 302 itself may comprise one or more external attachment portions 314 configured to attach the INS housing 302 to the surface of the skull. The one or more external attachment portions 314 may comprise any one or more features ofthe external attachment portions 114 extending from cradle 104, as described in greater detail below. For example, the one or more external attachment portions 314 may extend from the first enclosure portion and / or the second enclosure portion to attach the INS housing 302 to the human skull. INS housing 302 may comprise 2, 3, 4 or more external attachment portions 314. For example, FIG. 3 illustrates four external attachment portions 314, each extending from a quadrant of the INS housing 302. In some embodiments, the one or more external attachment portions extending from INS housing 302 may be disposed on a top surface of INS housing 302 such that, when the INS housing 302 is inserted to an opening in the skull, the depth to which the INS housing 302 is inserted can be limited by the one or more external attachment portions 314 contacting the surface of the skull. The one or more external attachment portions 314 may comprise one or more through-holes 316 or other attachment mechanisms configured to secure the INS housing 302 to the skull. The one or more through- holes may be configured to receive a corresponding pin, thread, etc. In some embodiments, each of the one or more external attachment portions 314 may comprise 1, 2, 3, 4 or more through-holes 316. The one or more through-holes 316 may be disposed at a distal end of the external attachment portion 314 (e.g., in a triangular fashion), along the length of the external attachment portion 314 (e.g., in a linear fashion), etc. Variations of the arrangement of the through-holes on the external attachment portions are illustrated at least in FIG. 1C, 2A, and 3.

[0051] In some embodiments, a method of assembling an implantable neurostimulator (INS) contained in an INS housing is provided herein. The method may comprise positioning a control circuit 140 on an inner surface of the INS housing 302. The inner surface of the INS housing 302 on which the control circuit 340 can be positioned may be of a first enclosure portion, a second enclosure portion, or each of first and second enclosure portion, dependent on the design and configuration of the enclosure portions (described in greater detail above). The method may include electrically connecting a power source (e.g., power source 142) to the control circuit 140. The method may include attaching the first enclosure portion and the second enclosure portion to enclose the control circuit 140 within the INS housing 302. Attaching the first enclosure portion and the second enclosure portion may also enclose the power source (e.g., power source 142) within the INS housing 302. In some embodiments, the method of assembling the INS may comprise attaching a header portion of the INS housing 302 that comprises the lead connection port to a side of the first enclosure portion and / or second enclosure portion. For example, as described herein, INS housing 302 (e.g., first enclosure portion) may comprise a set screw block configured to be inserted to areceptacle of the INS housing 302 and may capture a proximal end of the lead. The set screw block may protrude from a side of the first enclosure portion. In some embodiments, the method of assembling the INS may comprise coupling the lead connector to the lead connection port. Coupling the lead connector to the lead connection port may comprise inserting the lead connector to the header and / or electrically connecting the lead connector and the lead connection port.

[0052] In some embodiments, a method of implanting an implantable neurostimulation system comprising a cranially mounted INS without a cradle in a human skull is provided herein. The method may comprise removing a portion of the human skull to create an opening in the human skull, the opening sized to receive an INS housing 302. In some embodiments, creating the opening in the skull may comprise using a cutting tool and a cutting template to create an opening in the skull that is sized appropriately for the INS housing 302. For example, a cutting template comprising a profile corresponding with the shape of the INS housing 302 may be traced onto the skull, and one or more cutting tools (e.g., a drill, saw, etc.) may be used to create an opening sized for the INS housing 302. In some embodiments, the method may include implanting one or more leads into the brain tissue through the opening prior to implanting the INS housing 302 in the opening.

[0053] In some embodiments, the method may include generating one or more burr holes in the human skull proximate to the opening for the INS housing 302. This burr hole generation may occur before or after implanting the INS housing 302 into the corresponding opening. The one or more burr holes may be generated for implanting one or more leads through the skull and into the brain tissue. Thus, the method may comprise, subsequent to generating the one or more burr holes, implanting one or more leads through the burr hole into the brain tissue. Implanting the one or more leads may employ well-understood techniques such as MRI guided approaches and / or stereotactic frames for targeting the appropriate lead implant site in the brain tissue. The lead brain target may be clinically determined according to the symptom(s) to be addressed.

[0054] Following creation of the opening for the INS housing 302, the INS implanting method may include inserting the INS housing 302 into the opening in the human skull such that an external surface of the INS housing 302 is flush with a surface of the human skull. As described herein, the external surface of the INS housing 302 may comprise a curved profile that corresponds to a curvature of the surface of the human skull. The method may comprise attaching the INS housing 302 to the human skull at one or more external attachment portionsmay comprise one or more through-holes 316 configured to receive one or more corresponding pins, screws, etc. that attach the INS housing 302 to the skull surface.

[0055] In some embodiments, the method may include electrically connecting the one or more leads to a lead connector (e.g., lead connector 108) within the INS housing. For example, the lead connector may be housed in a header portion (e.g., header 110) of the INS housing. As explained herein, the lead connector may be electrically connected to a control circuit enclosed within the INS housing 302 such that connecting the one or more leads to the lead connector electrically connects the one or more leads to the control circuit. Connecting the one or more leads to the lead connector may occur before or after the INS housing 302 is implanted into the opening in the skull.Implantable Neurostimulator Cradle

[0056] Returning to the implantable neurostimulation system 100 illustrated in FIGS. 1A- II, as mentioned above, the INS housing 102 may be implanted in the human skull by implanting a cradle 104 into the skull, the cradle 104 configured to receive the INS housing 102. The cradle 104 may be implanted in an opening in the skull such that an external surface of the INS housing 102 is flush with a surface of the human skull when the INS housing 102 is disposed in the cradle 104. For example, cradle 104 may comprise a thickness substantially equivalent to that of the INS housing 102 described herein (and therefore substantially equivalent to or less than the thickness of the human skull), such that when the cradle 104 is implanted to the skull, the cradle 104 and the INS housing 102 disposed in the cradle 104 may not protrude from the surface of the skull. In some embodiments, the thickness of cradle 104 as measured between a first (e.g., open) side of cradle 104 and a second (e.g., bottom) side of cradle 104 may be between about 6 mm and 14 mm. The thickness of the cradle 104 may be limited by anatomical measurement data of human skull thicknesses, such that the cradle 104 does not protrude substantially into the skull toward the brain tissue or out of the skull toward the scalp.

[0057] As shown in FIGS. IE- IF, the cradle 104 may comprise a receptacle configured to receive the INS housing 102. In some embodiments, the size and / or shape of the receptacle may be substantially the same as that of the INS housing 102. For example, the cradle 104 may be sized such that the INS housing 102 can be inserted and removed from cradle 104 without large gaps between the walls of cradle 104 and the INS housing 102. The shape of cradle 104 may comprise an obround profile corresponding to the obround profile of INS housing 102. In some embodiments, the shape of cradle 104 may comprise an oblong, round,ovular, or other profile similar to that of INS housing 102. The dimensions (e.g., length, width, etc.) of the cradle 104 may be about 0.1-3 mm greater than the dimensions of the INS housing 102 to ensure a slip fit between the components. In some embodiments, a length of cradle 104 (e.g., a horizontal distance along the X-axis in FIGS. 1A-1B between a first side of the cradle 104 an opposite second side of the cradle 104) may be about 0. 1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, or 3 mm greater than a length of INS housing 102. In a similar manner, a width of cradle 104 (e.g., a vertical distance along the Y-axis in FIGS. 1A-1B between a first side of cradle 104 and an opposite second side of cradle 104) may be about 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, or 3 mm greater than a width of INS housing 102. The aforementioned dimensions of cradle 104 can be understood to be the dimensions of the receptacle of cradle 104 (e.g., not including the outer wall of cradle 104, which is described separately below).

[0058] A wall thickness of cradle 104 may be uniform or non-uniform throughout the cradle 104. For example, the wall thickness may be between 0.1-3 mm. In some embodiments, the wall thickness of cradle 104 may be greater than or equal to about 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, or 2.8 mm. In some embodiments, the wall thickness of cradle 104 may be less than or equal to 3 mm, 2.8 mm, 2.5 mm, 2.2 mm, 2 mm, 1.8 mm, 1.5 mm, 1.2 mm, 1 mm, 0.8 mm, 0.5 mm, or 0.2 mm.

[0059] As illustrated in FIGS. 1A-1G, cradle 104 may comprise one or more external attachment portions 114 configured to attach the cradle 104 to the human skull. In some embodiments, the external attachment portions 114 may extend from an upper edge of the cradle 104. The external attachment portions 114 may comprise any one or more features of external attachment portions 314, except rather than extending from the INS housing 302 (or INS housing 102, for that matter), the one or more external attachment portions 114 may extend from the cradle 104. The one or more external attachment portions 114 may comprise one or more through-holes 116 for securing the cradle 104 to the skull. An external attachment portion 114 may comprise 1, 2, 3, 4, or more through-holes 116. As described herein with respect to external attachment portions 314 and through-holes 316, the arrangement of the through-holes 116 on the external attachment portion 114 may be in a linear fashion along the length of the external attachment portion 114, at a distal end of the external attachment portion 114, etc. As illustrated in the Figures, the cradle 104 may in some embodiments comprise four external attachment portions 114, each attachment portiondisposed approximately in a quadrant of the cradle 104. In some embodiments, cradle 104 may alternatively comprise 1, 2, 3, or more than four external attachment portions 114. The external attachment portions 114 may be configured such that the cradle 104 can be inserted into the corresponding opening in the skull until the one or more external attachment portions 114 engage with the surface of the skull.

[0060] In some embodiments, the cradle 104 may comprise one or more openings operably connected to the lead connection port 106 and configured to receive one or more leads. For example, FIGS. 2A-2B illustrate an implantable neurostimulation system 200 comprising a cradle 204 with one or more openings 246a, 246b. The implantable neurostimulation system 200 may comprise any one or more features of implantable neurostimulation system 100. For example, neurostimulation system 200 may comprise an INS housing 202 comprising a header portion (e.g., header) 210. However, rather than comprising a lead connection port extending from the header 210 of the INS housing at a top surface of the INS housing 202, the lead connection port may be disposed at a bottom surface of the INS housing 202. The header 210 may house a lead connector comprising electrical contacts that facilitate electrical connection between one or more leads inserted to the lead connector via the lead connection port and the internal components of the INS within the INS housing 202.

[0061] The cradle 204 may comprise an opening 246a positioned such that, when INS housing 202 is disposed in cradle 204, the lead connection port of the INS housing 202 can be accessed through the opening 246a to connect to one or more leads 244 implanted (or to be implanted) into brain tissue. By implanting the leads 244 into brain tissue through the opening(s) in cradle 204 (or alternatively, by implanting the leads 244 into the brain tissue, followed by implanting the cradle 204 in the skull such that the leads 244 are fed through the one or more openings 246a, 246b), the need for additional burr hole(s) for lead implantation proximate to the implant site for the INS / cradle can be negated. In some embodiments, the opening 246a may be sized such that it can receive one or more leads 244 with limited additional space (e.g., the diameter or size of the opening 246a may be substantially the same as that of a single lead or a bundle of leads). In some embodiments, the openings (e.g., opening 246a and / or 246b) may cover 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of a bottom surface of cradle 204. The shape of opening 246a and / or 246b may be oblong, obround, circular, ovular, triangular, rectangular, square, or another polygonal shape.

[0062] In some embodiments, cradle 204 may comprise a first opening 246a that facilitates a connection between the lead connection port and the brain tissue for the one ormore leads 244, and a second opening 246b for containing any excess lead length of the one or more leads 244. In some embodiments, a single opening (e.g., opening 246a) may facilitate lead connection to the lead connection port and may be used to tunnel remaining lead 244. In some embodiments, the second opening 246b may instead comprise a recession (i.e., not a through-hole) in the bottom surface of the cradle 204 for tunneling any excess lead. This recession may be disposed within an inner or an outer surface of the bottom surface of the cradle 204. The first opening 246a and second opening 246b can be connected by a lead pathway to guide excess lead to the second opening 246b and maintain the position of the lead between the openings. In any instance, the need to tunnel excess lead length between the scalp and the skull, which could cause scalp erosion over time, can be negated by tunneling the excess lead(s) 244 within openings in the cradle (e.g., opening 246a and / or 246b).

[0063] In some examples, a cradle described herein may include one or more ports configured to receive one or more leads implantable into the brain tissue. The cradle may facilitate connection between the one or more leads and the INS configured to be inserted into the cradle by including a corresponding connector that mates to a connector on the INS for transmitting signals between the one or more leads and the INS. This arrangement may be particularly beneficial for subsequent imaging (e.g., magnetic resonance imaging, MRI) and / or INS replacement procedures that may take place following the initial INS implantation. For example, these procedures may only require the INS to be removed, rather than having to connect / disconnect leads from the INS or remove the leads from implantation within the brain tissue. This can be beneficial to reduce risk associated with damaging the leads and shorten surgical times by minimizing the number of steps in the surgical procedure.

[0064] Each of INS housing 102 and cradle 104 may comprise one or more attachment portions (e.g., internal attachment portions) configured to removably secure the INS housing 102 to the cradle 104. For example, FIGS. 1E-1F illustrate a protrusion 128 extending from INS housing 102 and configured to be inserted to a corresponding opening 130 of cradle 104. In an alternative embodiment, the cradle 104 may comprise a protrusion and the INS housing 102 may comprise a recession or opening for the protrusion. In some embodiments, the INS housing 102 or cradle 104 may comprise one or more spring-loaded arms, tabs, etc. configured to removably secure the INS housing 102 and the cradle 104. Although illustrated at one side of the system in the Figures, it is to be understood that the aforementioned securing mechanism may be disposed elsewhere on the INS housing 102 and cradle 104, for example, on an alternative side of the INS housing 102 and the cradle 104. In some embodiments, the system may comprise more than one of the aforementioned securingmechanisms to secure the INS housing 102 to the cradle 104 at multiple locations in the system (e.g., at each end of the system).

[0065] In some embodiments, in addition to or instead of the aforementioned securing mechanism(s), the INS housing 102 and cradle 104 may comprise one or more threaded mechanisms that can secure the INS housing 102 to the cradle 104. FIGS. 1G-1H illustrate a cross-sectional view of an example threaded mechanism comprising a screw 118, a receiving portion 132 of the INS housing 102, and a receiving portion 134 of the cradle 104. The receiving portion 132 of the INS housing 102 may extend from the top (external) surface of INS housing 102 into the receptacle of INS housing 102. The receiving portion 134 of cradle 104 may extend from an internal bottom surface of the cradle 104 into the receptacle of INS housing 102. When the INS housing 102 is appropriately positioned above the cradle 104, the screw 118 can be inserted to the receiving portion 132 of INS housing 102 and threaded until a portion (e.g., the head) of the screw 118 meets a corresponding surface within housing 102. The body of the screw 118 may comprise threads that correspond to internal threads of the receiving portion 134 of cradle 104. In some embodiments, INS housing 102 may be provided with screw 118 loosely secured in receiving portion 132 of INS housing 102, such that, upon proper positioning of INS housing 102 above cradle 104, the screw 118 can be threaded into receiving portion 134 of cradle 104 until the screw 118 is tightened to secure the INS housing 102 to the cradle 104.

[0066] In an alternative embodiment, the screw 118 may be provided as loosely secured to and extending from the cradle 104, such that the threaded portion of screw 118 is exposed outside of receiving portion 134. In this instance, upon proper positioning of the INS housing 102 above the cradle 104, a rotatable, threaded receiving portion of INS housing 102 (or a separate component configured to disposed in the receiving portion 132 of INS housing 102) may be threaded to the screw 118 to secure the INS housing 102 to the cradle 104. In any instance, this threaded mechanism may be disposed at a first location of the system (e.g., proximate to an end, as illustrated). In some embodiments, the system 100 may comprise more than one threaded mechanism to secure the INS housing 102 to the cradle 104 (e.g., a threaded mechanism proximate to each end of the system). In some embodiments, as illustrated by FIGS. 1A-1I, the system 100 may comprise a combination of mechanisms that removably secure the INS housing 102 to the cradle 104. For example, the system may comprise the securing mechanism including the protrusion 128 and opening 130 on a side of the cradle 104 and the INS housing 102, and the threaded securing mechanism comprising receiving portions 132, 134 and screw 118 at an opposite side of the cradle 104 and the INShousing 102. In this manner, as suggested by FIGS. 1E-1F, the INS housing 102 can be inserted to the cradle 104 by first inserting the protrusion 128 to the opening 130 (whether the protrusion 128 is of the INS housing 102 and the opening 130 is of the cradle 104, or vice versa). Once the INS housing 102 is inserted to the cradle 104, the screw 118 can be fastened to fully (removably) secure the INS housing to the cradle 104.

[0067] In some embodiments, INS housing 102 and / or cradle 104 may comprise one or more holes 129 that can be leveraged during removal of the INS housing 102 from the cradle 104, as will be described in greater detail herein with reference to the method of replacing the INS. The hole(s) 129 may be configured to receive a surgical instrument to maneuver the INS housing 102 out of cradle 104 (e.g., the protrusion 128 of the INS housing 102 out of the opening 130 in cradle 104). The one or more holes 129 may be positioned on a side of the INS housing 102 and / or cradle 104, on a top surface of INS housing 102, or combinations thereof.

[0068] In some embodiments, a method for assembling an implantable neurostimulation system comprising an INS housing 102 and a cradle 104 is provided herein. The method may include inserting a control circuit 140 into the INS housing 102 and enclosing the control circuit 140 within the INS housing 102. In some embodiments, prior to enclosing the control circuit within the INS housing 102, the method may include electrically connecting a power source (e.g., power source 142) to the control circuit 140. In this manner, enclosing the control circuit 140 within the INS housing 102 may include enclosing the power source within the INS housing 102. In some embodiments, the INS housing 102 may comprise a first enclosure portion (e.g., first enclosure portion 102a) and a second enclosure portion (e.g., second enclosure portion 102b), such that enclosing the control circuit 140 within the INS housing comprises attaching the first enclosure portion and the second enclosure portion. The first and second enclosure portion may be hermetically sealed, e.g., via a weld. In some embodiments, the method may include attaching a header portion 110 of the INS housing to a side of the first enclosure portion and / or the second enclosure portion. The header portion (e.g., header) may comprise a lead connection port 106 for connecting one or more leads to a lead connector 108 electrically connected to the internal circuitry components of the INS. In some embodiments, the method may comprise coupling the lead connector 108 to the lead connection port 106. The method may comprise placing the INS housing 102 in the cradle 104 and attaching the INS housing 102 to the cradle 104, the cradle 104 configured to be implanted in the opening in the human skull. The INS housing 102 may be attached to the cradle 104 prior to or after implantation of the cradle 104 in the skull. In some embodiments,attaching the INS housing 102 to the cradle 104 may comprise connecting one or more attachment portions of INS housing 102 to one or more corresponding attachment portions of cradle 104. For example, the attachment portion 132 of INS housing 102 and attachment portion 134 of cradle 104 may be attached, e.g., using a screw 118. The protrusion 128 of INS housing 102 may be inserted to the opening 130 of cradle 104.

[0069] In some embodiments, a method for implanting an implantable neurostimulator (INS) in a human skull may be provided herein. The INS may comprise an INS housing 102 configured to be received by a cradle 104. In other words, the cradle 104 may retain the INS. The method may comprise removing a portion of the human skull to create an opening in the human skull sized to receive the cradle 104. For example, a portion of the human skull in the left parietal region or the right parietal region of the skull, as illustrated generally in FIG. 4, may be removed. In some embodiments, creating an opening in the human skull comprises tracing an outline of a cutting template on the human skull, a profile of the cutting template corresponding with a curved profile of the cradle. In some embodiments, the method may comprise generating a burr hole in the human skull proximate to the opening for the cradle 104 and implanting one or more leads into brain tissue through the burr hole. In some embodiments, rather than generating additional hole(s) in the skull, the method may include implanting the one or more leads into brain tissue through the opening for the cradle 104. In this instance, the cradle may comprise one or more openings on a bottom surface of the cradle (e.g., openings 246a, 246b as described herein with respect to cradle 204) configured to facilitate the connection between the INS and leads implanted to the brain tissue.

[0070] In some embodiments, the method may include electrically connecting one or more leads to the lead connector 108 of the INS. The lead connector 108 may be electrically connected to a control circuit 140 enclosed within the INS, such that connecting the one or more leads to the lead connector 108 electrically connects the one or more leads to the control circuit 140. The lead connector 108 may be housed in the header 110 of the INS.

[0071] Prior to or after implanting the cradle 104 in the skull, the method may comprise placing the INS in the cradle 104 and removably attaching the INS to the cradle 104. The INS may be attached to the cradle 104 at one or more attachment portions of the INS that correspond to one or more internal attachment portions of the cradle 104. For example, the attachment portion 132 of INS housing 102 and attachment portion 134 of cradle 104 may be attached, e.g., using a screw 118. The protrusion 128 of INS housing 102 may be inserted to the opening 130 of cradle 104. The method for implanting the INS into the human skull may comprise implanting the cradle 104 in the opening in the human skull such that an externalsurface of the INS is flush with a surface of the human skull. As described herein, the external surface of the INS (e.g., of the INS housing 102) may have a curved profde corresponding to a curvature of the surface of the human skull. The cradle 104 may be attached to the human skull at one or more external attachment portions 114 of the cradle 104.

[0072] In some embodiments, a method for replacing an implantable neurostimulator (INS) previously implanted in the skull is provided herein. Due at least to the longevity (e.g., battery life) of internal components within the INS, it is expected that over time, the INS may need to be removed and replaced with a new INS. The implantable neurostimulation systems described herein may reduce risk associated with subsequent procedures for INS replacement by including a cradle that can be implanted within the skull to receive the INS, rather than implanting the INS itself into the skull. During replacement, the cradle does not need to be removed from the skull. Rather, the INS can be removed from the cradle and replaced with a replacement INS. In this manner, no additional cutting of the skull may be necessary.

[0073] The method for replacing the INS may include cutting and retracting a portion of the scalp corresponding to the implanted location of the INS. The method may subsequently comprise removing the existing INS from the cradle 104 implanted in the skull. Removing the INS from the cradle 104 may comprise detaching the INS housing 102 of the INS from the cradle 104 at one or more attachment portions of the INS housing 102 attached to one or more corresponding attachment portions of the cradle 104. The method may include disconnecting one or more leads implanted in the brain tissue from the INS. In some embodiments, the leads may be implanted in the brain tissue through one or more openings in the cradle (e.g., as shown and described with respect to cradle 204 in FIGS. 2A-2B), or alternatively, the one or more leads may be implanted in the brain tissue via one or more proximate burr holes. In some embodiments, the method may comprise replacing one or more of the leads. Replacing one or more of the leads may comprise removing the lead(s) from the brain tissue and implanting one or more replacement leads into the brain tissue.

[0074] The method for replacing the INS may include electrically connecting the one or more leads (e.g., existing leads and / or replacement leads) to a replacement INS. The replacement INS may be inserted into the cradle 104 implanted in the human skull. The replacement INS can be attached to the cradle 104 in a similar manner as described herein (e.g., via one or more attachment portions on the cradle 104 and the INS housing 102). Following insertion and securing of the INS, the method may comprise replacing the portion of the scalp previously retracted. In this manner, the replacement method may not compriseresecting any additional portion of the human skull. Moreover, the method may not comprise replacing the cradle 104.

[0075] In some embodiments, methods for performing an imaging procedure on a human having an implantable neurostimulator (INS) implanted in the skull of the human are provided herein. It is possible that patients having implantable neurostimulators will need to undergo imaging, in particular, imaging in the cranial region, while having an INS implanted in the skull of the patient. However, imaging techniques may be incompatible with the hardware of the INS and thus may risk damaging the device and / or harming the patient should the device remain implanted during the imaging procedure. Exemplary imaging procedures may include imaging procedures of at least a portion of the brain of the patient, such as magnetic resonance imaging (MRI) of the brain of the subject.

[0076] In some examples, the INS may be removed for any MRI imaging procedure (e.g., 1.5T, 3T, or greater). In some examples, the INS may only need to be removed for MRI strengths greater than a threshold, e.g., greater than 1.5T (such as 3T or greater). In some examples, the INS may be retained in the cradle during imaging procedures such as MRI. For example, the INS may be retained in the cradle so long as it is not stimulating during the imaging procedure. In some examples, the INS may be retained in the cradle during the imaging procedure and may be used to stimulate the patient during the imaging procedure.

[0077] The method for performing the imaging procedure can include cutting and retracting a portion of the scalp corresponding to the location of the implanted INS. Once retracted, the INS can be removed from a cradle implanted in the skull. The cradle itself can remain implanted in the skull. One or more leads implanted into the brain tissue may also remain implanted. Thus, the method can include disconnecting the leads implanted in the brain tissue from the INS. Alternatively, in some examples, the method can include removing one or more leads connected to the INS from implantation within the brain tissue. For example, the bottom surface of the cradle includes an opening such that removing the leads from the brain tissue includes removing the leads through the opening in the cradle. In this example, the one or more leads may not be disconnected from the INS.

[0078] In some examples, the method includes inserting a nonconductive, sterile body into the cradle following removal of the INS from the cradle and prior to performing the imaging procedure on the human. The nonconductive body may be made of a polymer material, such as polypropylene, polyethylene, polyether ether ketone (PEEK), polycarbonate (PC), polyphenylsulfone (PPSU), Polyethylene terephthalate (PET), or a mixture thereof. In some examples, the nonconductive body may additionally or alternatively be made of aceramic material. The profile of the nonconductive body may mimic the profile of the cradle and thus the INS housing. For example, the nonconductive body may have a similar size and shape as the INS housing so that it fits into the cradle in the same fashion as the INS housing. The nonconductive body may be used when the one or more leads are left implanted in the brain tissue during the imaging procedure to block any electrical path that may form between the cradle and the one or more leads while the INS is removed from the cradle, in particular, during imaging. The non-implanted ends of the one or more leads may be inserted to the nonconductive body while the body is inserted into the cradle to isolate the leads. Once the nonconductive body is inserted into the cradle, the portion of the scalp that was retracted for removing the INS may be replaced for the imaging procedure. This portion of the scalp may be held in place using, for example, staples (e.g., staples of a non-ferromagnetic material, such as a polymer), surgical tape, and / or bandages.

[0079] The method can include performing the imaging procedure on the human. As noted above, the imaging procedure can be an MRI or other type of medical imaging procedure of at least a portion of the brain. Following the imaging procedure, the method can include retracting the portion of the scalp to create access to the INS implantation location again. This can include removing one or more staples, bandages, and / or surgical tape from the implantation location. If it was used, the method may further include removing the nonconductive block from the cradle and removing the lead ends from the nonconductive block. The method may include reimplanting the one or more leads connected to the INS into the brain tissue (if they were previously removed from the brain tissue). The method may additionally or alternatively include reconnecting the one or more leads implanted in the brain tissue to the INS. With the leads again implanted to the brain tissue, the INS can be reinserted into the cradle in the skull. The leads may be reconnected to the INS before or after the INS is reinserted to the cradle. The portion of the scalp previously retracted for removing the INS can be replaced. The portion of the scalp may be held in place following the imaging procedure using surgical staples, tape, and / or bandages.

[0080] In another embodiment, the cradle can include a one or more ports for connecting to the one or more leads implanted into the brain tissue. The one or more leads may connect to the implantable neurostimulator via the cradle because the INS and cradle may include corresponding connectors for transmitting signals to / from the one or more leads and the INS. In this example, the method for performing an imaging procedure may include, after retracting a portion of the skull, simply removing the INS from the cradle, performing the imaging procedure, reinserting the INS into the cradle implanted in the skull following theprocedure, and replacing the scalp. Corresponding mating connectors on the cradle and INS for transmitting signals between the INS and lead(s) implanted into the brain tissue can further shorten the length of the surgical procedure, reduce the risk of damage to the lead(s), and / or simplify the imaging procedure.

[0081] The methods for performing an imaging procedure described herein may be particularly advantageous in reducing any risk associated with performing imaging procedures on patients having implanted neurostimulators due to the cradle implanted to the skull. Rather than having to completely remove the implantable neurostimulation system from the skull for imaging, the cradle can remain in place in the skull during the imaging procedure, thus no cutting or other surgical manipulation of the skull is necessary to prepare and recover from the imaging procedure.Implantable Neurostimulator (INS)

[0082] In some embodiments, an implantable neurostimulator (INS) may comprise an INS housing (e.g., INS housing 102) and a control circuit 140 disposed within the INS housing, the control circuit configured to generate electrical stimulation for brain tissue.

[0083] The control circuit 140 may include an application-specific integrated circuit (ASIC) and / or a low-power microcontroller configured to control the ASIC and other electronic components of the INS. In some embodiments, the INS may comprise a power management unit configured to store and distribute energy to components of the INS (understood to encompass the power source 142), a modulation circuit configured to encode information in an electric current, a transmitter configured to wirelessly receive, convert, and transfer energy from an external device (e.g., the interrogator), and / or a memory configured to store data received from one or more sensors (e.g., electrodes).

[0084] The control circuit 140 may be configured to provide current stimulation to one or more leads. Each lead may comprise one or more electrical contacts (e.g., electrodes, described in greater detail below), such as 2, 3, 4, 5, 6, 7, 8 or more electrical contacts. The lead(s) may be similar in size, material, construction methods, contact geometry, etc. to leads commonly used in the field. For example, leads for use in the INS system herein may be 1-2 mm in diameter (e.g., 1.3 mm), comprise ethylene tetrafluoroethylene copolymer (ETFE) conductive wire insulation material, and / or 55D urethane lead body material. The segmented lead(s) may enable current steering. The pulse width, frequency, and amplitude of the current may be programmable.

[0085] The implantable neurostimulator may comprise one or more electrodes electrically coupled to the control circuit and configured to provide the generated electrical stimulation to the brain tissue. In some embodiments, one or more electrodes of the one or more leads may be configured to measure an evoked action potential and / or a local field potential in the brain. The one or more electrodes may comprise platinum-iridium conductive wire. The electrodes may comprise a 1-3-3-1 or other similar electrode geometry, 1-2 mm (e.g., 1.5 mm) electrode length, and 0.1-1 mm (e.g., 0.5 mm) electrode spacing.

[0086] The INS may comprise a power source 142 electrically coupled to the control circuit 140 and configured to be disposed within the INS housing 102. The power source 142 may be a battery. The battery may be rechargeable, for example wirelessly via an inductive coil 122. The battery may be a 50 mAH lithium-ion rechargeable battery. The power source 142 may be configured to power the INS for at least 3 days within 1 charge of the battery.

[0087] The implantable neurostimulator may comprise an inductive coil 122 electrically coupled to the control circuit 140 for power transfer and / or communication. The inductive coil 122 may comprise one or more biocompatible and inductive materials, such as gold. As explained above, the inductive coil 122 may be disposed external to the INS housing 102, positioned between the scalp and the surface of the scalp once properly implanted. The inductive coil 122 may fulfill the power requirements of the INS while being within the specific absorption rate (SAR) and thermal standards for implantable neurostimulation systems. The coil may enable 1C charging (1C = 45 minutes for 80% charge) of the power source 142.

[0088] The control circuit 140 may alternatively or additionally comprise functionalities including but not limited to impedance measurement, compliance detection, and / or subsystem test interfaces. Impedance measurement may be an optional feature to check whether one or more electrodes of a given lead are adequately contacting tissue based on known tissue resistance. Compliance detection may be an optional feature to determine whether the current flowing in and out of electrode(s) matches the intended current flow values. For example, compliance detection circuitry may monitor the voltage drop across a current source / sink (which are connected to an electrode) and compare the voltage drop with a known value. The test interface may comprise a wired, serial peripheral interface (SPI) that enables calibration and ASIC control through a microcontroller.

[0089] In some embodiments, an implantable neurostimulation system may comprise the above-described INS and one or more external devices configured to communicate with the INS, such as an interrogator. As used herein, “external” may refer to any region outside of theimplantable neurostimulator (INS). The external device may be external to the patient in which the INS is implanted. In some embodiments, the external device may be implanted in the patient along with the INS, but may be separate from (e.g., external to) the INS. The external device may be communicatively coupled to the INS. The external device may be configured to wirelessly transmit signals to and receive signals from one or more components of the INS.

[0090] Powering of and / or communication with the INS may occur via an external device (e.g., the interrogator). The control circuit 140 of the INS may be configured to receive a command from the external device (e.g., interrogator), the command configured to cause the control circuit 140 to generate and provide electrical stimulation to the brain tissue via one or more electrodes. For example, the INS may comprise a radio frequency (RF) antenna coupled to the control circuit such that the control circuit can receive the command from RF waves emitted by the external device (e.g., interrogator). In some embodiments, the RF antenna or coil of the control circuit may receive energy from RF waves emitted by the external device and convert the RF waves into electrical current. The control circuit 140 and external device may communicate using radio wave backscatter. Alternatively, the control circuit 140 and the external device may communicate using active radio wave transmission. Radio wave transmission may be modulated using Amplitude modulation (AM), Frequency modulation (FM), Phase modulation (PM), Pulse-code modulation (PCM), Polarization modulation, Quadrature amplitude modulation (QAM), or any other appropriate modulation scheme. In some embodiments, as explained above with reference to inductive coil 122, the RF antenna may be implanted beneath the scalp but external to the INS housing 102.

[0091] Alternatively, in some embodiments, the INS may comprise one or more ultrasonic transducers coupled to the control circuit 140 such that the control circuit can receive the command from ultrasonic waves emitted by the external device (e.g., interrogator). In some embodiments, the one or more ultrasonic transducers of the INS may be configured to receive energy from the ultrasonic waves emitted by the external device and convert the ultrasonic waves into electrical current. The control circuit and the external device may communicate using ultrasonic backscatter. Alternatively, the control circuit 140 and the external device may communicate using active ultrasonic wave transmission. Ultrasonic wave transmission may be modulated using Amplitude modulation (AM), Frequency modulation (FM), Phase modulation (PM), Pulse-code modulation (PCM), Polarization modulation, Quadrature amplitude modulation (QAM), or any other appropriate modulation scheme. The one or more ultrasonic transducers may be disposed within the INShousing 102. The one or more ultrasonic transducers may comprise a bulk piezoelectric transducer, a piezoelectric micro-machined ultrasonic transducer (PMUT), or a capacitive micro-machined ultrasonic transducer (CMUT).

[0092] In the instance the INS comprises one or more ultrasonic transducers, the ultrasonic transducer(s) may include a piezoelectric crystal configured to receive commands from ultrasonic energy transmitted from the external interrogator. The INS may decode pulse interval encoded commands transmitted from the external interrogator and may passively transmit data to the external device via amplitude-modulated, backscatter communication. In some embodiments, the INS receives ultrasonic waves from the external device through one or more ultrasonic transducers on the INS, and the received waves can encode instructions for operating the INS. For example, vibrations of the ultrasonic transducer(s) on the device generate a voltage across the electric terminals of the transducer, and current flows through the device, including the integrated circuit. The current (which may be generated, for example, using one or more ultrasonic transducers) can be used to charge an energy storage circuit.

[0093] The interrogator may comprise a communication circuit, a transmitter, and / or a power management circuit. The transmitter may be configured to wirelessly transmit energy to the INS. Energy that is transmitted to the INS by the transmitter may include any form of energy that originates from outside of the INS. For example, as mentioned above, the transmitter of the interrogator may comprise one or more transducers configured to transmit energy to the INS in the form of ultrasonic waves. In some embodiments, the transmitter of the interrogator may comprise one or more antennas or coils configured to transmit energy to the INS in the form of electromagnetic waves, such as radio frequency (RF) waves. The transmitter of the interrogator (e.g., the transducer) may be configured to transmit instructions to the INS, such as instructions to reset itself, enter a specific mode, set device parameters, and / or begin a transmission sequence. The interrogator may be configured to communicate with and / or provide power to the INS when appropriately placed over the patient’s scalp proximate to the INS. The interrogator may be a wearable device above the scalp of the patient.

[0094] The communication between the INS and the external device may be a one-way communication (for example, the external device transmitting information to the INS, or the INS transmitting information to the external device), or a two-way communication (for example, the interrogator transmitting information to the INS, and the INS transmitting information to the interrogator). Information transmitted from the INS to the external devicemay rely on, for example, a backscater communication protocol. For example, the external device may transmit ultrasonic waves to the INS, which may emit backscater waves that encode the information. The external device can receive the backscater waves and decipher the information encoded in the received backscater waves.

[0095] In some embodiments, a method for stimulating brain tissue may comprise providing energy to the implantable neurostimulator (INS) and stimulating the brain tissue using electrical stimulation generated by the control circuit 140 and provided to the brain tissue via one or more electrodes electrically coupled to the control circuit 140. For example, the energy may be provided via electromagnetic waves (e.g., RF waves) or ultrasonic waves transmited by an external device (e.g., interrogator). The control circuit 140 may be configured to convert the energy to electrical current that can be passed through one or more leads implanted in the brain tissue to stimulate the tissue.

[0096] The implantable neurostimulator (INS) system described herein may in some embodiments comprise one or more additional external devices, such as a patient remote controller (e.g., “controller”) and / or a clinician programmer tablet (e.g., “programmer”).

[0097] The clinician’s programmer may be a mobile device (e.g., a smartphone, tablet, etc.) or other separate computer system. The programmer may be used for initial INS setup, programming therapy parameters, data collection, and / or follow-on patient care. The programmer may be configured to communicate with the INS via the interrogator. The programmer may wirelessly communicate with the interrogator, for example, through a network connection, a radio frequency (RF) connection, Bluetooth connection, etc. The computer system may, for example, turn on or off the interrogator or analyze information encoded in backscater waves (e.g., ultrasonic backscater waves or radio frequency backscater waves) received by the interrogator.

[0098] The patient remote controller may be a mobile device (e.g., a smartphone, tablet, etc.) or other separate computer system. The controller may allow the patient to control particular stimulation parameters, as advised by the clinician, and enter special modes (e.g., an MRI mode), as necessary. The controller may be configured to run validated application software. The controller may be configured to allow the patient to interact with the INS via the interrogator. The controller may wirelessly communicate with the interrogator, for example, through a network connection, a radio frequency (RF) connection, Bluetooth connection, etc. The computer system may, for example, turn on or off the interrogator or analyze information encoded in backscater waves (e.g., ultrasonic backscater waves or radio frequency backscater waves) received by the interrogator. Once a connection is established,the controller may allow the patient to receive real-time or near real-time information, such as information on battery life of components of the system (e.g., the interrogator, the INS, etc.).Definitions

[0099] As used herein, the singular forms “a”, “an”, and “the” include the plural reference unless the context clearly dictates otherwise.

[0100] Reference to “about” a value or parameter herein includes (and describes) variations that are directed to that value or parameter per se. For example, description referring to “about X” includes description of “X”.

[0101] It is understood that aspects and variations of the invention described herein include “consisting” and / or “consisting essentially of’ aspects and variations.

[0102] When a range of values or values is provided, it is to be understood that each intervening value between the upper and lower limit of that range, and any other stated or intervening value in that stated range, is encompassed within the scope of the present disclosure. Where the stated range includes upper or lower limits, ranges excluding either of those included limits are also included in the present disclosure.

[0103] The section headings used herein are for organization purposes only and are not to be construed as limiting the subject matter described. The description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the described embodiments will be readily apparent to those persons skilled in the art and the generic principles herein may be applied to other embodiments. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein.

[0104] The figures illustrate processes according to various embodiments. In the exemplary processes, some blocks are, optionally, combined, the order of some blocks is, optionally, changed, and some blocks are, optionally, omitted. In some examples, additional steps may be performed in combination with the exemplary processes. Accordingly, the operations as illustrated (and described in greater detail below) are exemplary by nature and, as such, should not be viewed as limiting.

[0105] Finally, it is to be understood that features and preferences described in relation to “embodiments” are distinct preferences and are not limited only to that particular embodiment; they may be freely combined with features from other embodiments, where technically feasible, and may form preferred combinations of features. The description ispresented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the described embodiments will be readily apparent to those persons skilled in the art and the generic principles herein may be applied to other embodiments. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein. Further, sectional headings are provided for organizational purposes and are not to be considered limiting.

[0106] The entire disclosure of the patents and publications referred in this application are hereby incorporated herein by reference for all purposes. To the extent that any reference incorporated by reference conflicts with the instant disclosure, the instant disclosure shall control.EMBODIMENTS

[0107] The following embodiments are exemplary and are not intended to limit the scope of any invention described herein.

[0108] Embodiment 1. An implantable neurostimulator (INS) housing, comprising: a lead connection port configured to receive one or more leads of an implantable neurostimulator; and a first enclosure portion and a second enclosure portion configured to attach to the first enclosure portion to enclose a control circuit for controlling brain neurostimulation, wherein at least one of the first enclosure portion and the second enclosure portion comprises an external surface having a curved profile corresponding to a curvature of a human skull.

[0109] Embodiment 2. The INS housing of embodiment 1, wherein the curved profile of the external surface comprises a constant spherical radius, a plurality of curvatures, or one or more non-uniform curvatures.

[0110] Embodiment 3. The INS housing of embodiment 1 or 2, wherein the curved profile of the external surface comprises a radius between 80 mm and 140 mm.[oni] Embodiment 4. The INS housing of any one of embodiments 1-3, wherein a shape of the INS housing comprises an obround profile.

[0112] Embodiment 5. The INS housing of any one of embodiments 1-4, wherein the first enclosure portion and the second enclosure portion are configured to hermetically seal to enclose the control circuit.

[0113] Embodiment 6. The INS housing of any one of embodiments 1-5, comprising a header portion that comprises the lead connection port and an external surface having the curved profde corresponding to a curvature of a human skull.

[0114] Embodiment 7. The INS housing of any one of embodiments 1-6, comprising one or more external attachment portions extending from the first enclosure portion and / or the second enclosure portion and configured to attach the INS housing to the human skull.

[0115] Embodiment 8. The INS housing of any one of embodiments 1-7, wherein a bottom surface of the first enclosure portion is configured to attach to a top surface of the second enclosure portion, such that a top surface of the first enclosure portion comprises the external surface having the curved profile corresponding to a curvature of a human skull.

[0116] Embodiment 9. The INS housing of any one of embodiments 1-7, wherein a side surface of the first enclosure portion is configured to attach to a side surface of the second enclosure portion, such that each of the first enclosure portion and the second enclosure portion comprises at least a portion of the external surface having the curved profile corresponding to a curvature of a human skull.

[0117] Embodiment 10. An implantable neurostimulation system, comprising: the INS housing of any one of embodiments 1-9; and a cradle configured to be implanted within the human skull and receive the INS housing.

[0118] Embodiment 11. The implantable neurostimulation system of embodiment 10, wherein the INS housing comprises one or more attachment portions that removably secure the INS housing to the cradle.

[0119] Embodiment 12. The implantable neurostimulation system of embodiment 10 or 11, wherein the cradle comprises one or more external attachment portions configured to attach the INS housing to the human skull.

[0120] Embodiment 13. The implantable neurostimulation system of any one of embodiments 10-12, wherein a bottom surface of the cradle comprises one or more openings operably connected to the lead connection port and configured to receive the one or more leads.

[0121] Embodiment 14. An implantable neurostimulator, comprising: the INS housing of any one of embodiments 1-13; and the control circuit disposed within the INS housing, the control circuit configured to generate electrical stimulation for brain tissue.

[0122] Embodiment 15. The implantable neurostimulator of embodiment 14, comprising one or more electrodes electrically coupled to the control circuit and configured to provide the generated electrical stimulation to the brain tissue.

[0123] Embodiment 16. The implantable neurostimulator of embodiment 15, comprising the one or more leads electrically connected to the control circuit, wherein the one or more electrodes are disposed on the one or more leads.

[0124] Embodiment 17. The implantable neurostimulator of embodiment 15 or 16, wherein the control circuit is configured to receive a command from an external device, the command configured to cause the control circuit to generate and provide the electrical stimulation to the brain tissue via the one or more electrodes.

[0125] Embodiment 18. The implantable neurostimulator of embodiment 17, comprising a radio frequency (RF) antenna coupled to the control circuit such that the control circuit receives the command from RF waves emitted by the external device.

[0126] Embodiment 19. The implantable neurostimulator of embodiment 17 or 18, wherein the control circuit is configured to communicate with the external device using radio wave backscatter.

[0127] Embodiment 20. The implantable neurostimulator of any one of embodiments17-19, comprising a radio frequency (RF) antenna coupled to the control circuit such that the control circuit receives energy from RF waves emitted by the external device.

[0128] Embodiment 21. The implantable neurostimulator of any one of embodiments18-20, wherein the RF antenna is configured to be implanted beneath the scalp external to the INS housing.

[0129] Embodiment 22. The implantable neurostimulator of embodiment 17, comprising one or more ultrasonic transducers coupled to the control circuit such that the control circuit receives the command from ultrasonic waves emitted by the external device.

[0130] Embodiment 23. The implantable neurostimulator of embodiment 17 or 22, wherein the control circuit is configured to communicate with the external device using ultrasonic backscatter.

[0131] Embodiment 24. The implantable neurostimulator of any one of embodiments 17, 22, or 23, comprising one or more ultrasonic transducers coupled to the control circuit such that the control circuit receives energy from ultrasonic waves emitted by the external device.

[0132] Embodiment 25. The implantable neurostimulator of any one of embodiments 22-24, wherein the one or more ultrasonic transducers are configured to be disposed within the INS housing.

[0133] Embodiment 26. The implantable neurostimulator of any one of embodiments 14-25, comprising a power source electrically coupled to the control circuit and configured to be disposed within the INS housing.

[0134] Embodiment 27. The implantable neurostimulator of embodiment 26, wherein the power source is a rechargeable battery.

[0135] Embodiment 28. An implantable neurostimulation system, comprising: the implantable neurostimulator of any one of embodiments 14-27; and an external device configured to communicate with the implantable neurostimulator.

[0136] Embodiment 29. A method for stimulating brain tissue, comprising: providing energy to the implantable neurostimulator of any one of embodiments 14-28; and stimulating the brain tissue using electrical stimulation generated by the control circuit and provided to the brain tissue via one or more electrodes electrically coupled to the control circuit.

[0137] Embodiment 30. A method for assembling an implantable neurostimulator (INS) contained in the INS housing of any one of embodiments 1-29, comprising: positioning a control circuit on an inner surface of the INS housing; and attaching a first enclosure portion of the INS housing and a second enclosure portion of the INS housing to enclose the control circuit within the INS housing.

[0138] Embodiment 31. The method of embodiment 30, comprising, prior to attaching the first enclosure portion and the second enclosure portion, electrically connecting a power source to the control circuit.

[0139] Embodiment 32. The method of embodiment 31, wherein attaching the first enclosure portion and the second enclosure portion encloses the power source within the INS housing.

[0140] Embodiment 33. The method of any one of embodiments 30-32, comprising attaching a header portion of the INS housing comprising the lead connection port to a side of the first enclosure portion and / or the second enclosure portion.

[0141] Embodiment 34. The method of embodiment 33, comprising coupling a lead connector to the lead connection port.

[0142] Embodiment 35. The method of any one of embodiments 30-34, comprising placing the INS housing in a cradle configured to be implanted in the human skull.

[0143] Embodiment 36. The method of embodiment 35, wherein placing the INS housing in the cradle occurs after the cradle is implanted in the human skull.

[0144] Embodiment 37. The method of embodiment 35 or 36, wherein placing the INS housing in the cradle comprises connecting one or more attachment portions of the INS housing with one or more corresponding attachment portions of the cradle.

[0145] Embodiment 38. A method for implanting an implantable neurostimulator (INS) in a human skull, comprising: removing a portion of the human skull to create an opening in the human skull sized to receive an INS housing; and inserting the INS housing into the opening in the human skull such that an external surface of the INS housing is flush with a surface of the human skull.

[0146] Embodiment 39. The method of embodiment 38, wherein the external surface of the INS housing comprises a curved profde corresponding to a curvature of the surface of the human skull.

[0147] Embodiment 40. The method of embodiment 38 or 39, wherein the method comprises generating a burr hole in the human skull proximate to the opening for the INS housing.

[0148] Embodiment 41. The method of embodiment 40, comprising implanting one or more leads into brain tissue through the burr hole.

[0149] Embodiment 42. The method of embodiment 38 or 39, wherein, prior to inserting the INS housing into the opening in the human skull, the method comprises implanting one or more leads into brain tissue through the opening.

[0150] Embodiment 43. The method of embodiment 41 or 42, comprising electrically connecting the one or more leads to a lead connector within the INS housing.

[0151] Embodiment 44. The method of embodiment 43, wherein the lead connector is electrically connected to a control circuit enclosed within the INS housing such that connecting the one or more leads to the lead connector electrically connects the one or more leads to the control circuit.

[0152] Embodiment 45. The method of embodiment 43 or 44, wherein the lead connector is housed in a header portion of the INS housing.

[0153] Embodiment 46. The method of any one of embodiments 38-45, wherein creating the opening in the human skull comprises tracing an outline of a cutting template on the human skull, wherein a profile of the cutting template corresponds with the shape of the INS housing.

[0154] Embodiment 47. The method of any one of embodiments 38-46, comprising attaching the INS housing to the human skull at one or more external attachment portions of the INS housing.

[0155] Embodiment 48. The method of any one of embodiments 38-46, comprising implanting a cradle configured to receive the INS housing into the opening in the human skull and attaching the cradle to the human skull at one or more external attachment portions of the cradle.

[0156] Embodiment 49. The method of embodiment 48, comprising removably attaching the INS housing to the cradle at one or more attachment portions of the INS housing that correspond to one or more internal attachment portions of the cradle.

[0157] Embodiment 50. An implantable neurostimulation system, comprising: an implantable neurostimulator (INS) comprising an INS housing configured to enclose a control circuit for controlling brain neurostimulation; and a cradle configured to be implanted in an opening in a human skull and to receive the INS housing.

[0158] Embodiment 51. The implantable neurostimulation system of embodiment 50, wherein the cradle is configured to be implanted in the opening of the human skull such that an external surface of the INS housing is flush with a surface of the human skull when the INS housing is disposed in the cradle.

[0159] Embodiment 52. The implantable neurostimulation system of embodiment 51, wherein the external surface of the INS housing has a curved profile corresponding to a curvature of the human skull.

[0160] Embodiment 53. The implantable neurostimulation system of any one of embodiments 50-52, wherein the cradle comprises one or more internal attachment portions configured to removably secure the INS housing to the cradle.

[0161] Embodiment 54. The implantable neurostimulation system of any one of embodiments 50-53, wherein the cradle comprises one or more external attachment portions configured to attach the cradle to the human skull.

[0162] Embodiment 55. The implantable neurostimulation system of embodiment 54, wherein the one or more external attachment portions extend from an upper edge of the cradle.

[0163] Embodiment 56. The implantable neurostimulation system of any one of embodiments 50-55, wherein a shape of the INS housing comprises an obround profile.

[0164] Embodiment 57. The implantable neurostimulation system of embodiment 56, wherein a shape of the cradle comprises an obround profile corresponding to the profile of the INS housing.

[0165] Embodiment 58. The implantable neurostimulation system of any one of embodiments 50-57, wherein the INS housing comprises a lead connection port configured toreceive one or more leads of the INS, a first enclosure portion, and a second enclosure portion configured to attach to the first enclosure portion to enclose the control circuit.

[0166] Embodiment 59. The implantable neurostimulation system of embodiment 58, wherein the first enclosure portion and / or the second enclosure portion comprises the external surface having a curved profile corresponding to a curvature of a human skull.

[0167] Embodiment 60. The implantable neurostimulation system of embodiment 58 or 59, wherein the first enclosure portion and the second enclosure portion attach are configured to hermetically seal to enclose the control circuit.

[0168] Embodiment 61. The implantable neurostimulation system of any one of embodiments 58-60, comprising a header portion that comprises the lead connection port and an external surface having the curved profile corresponding to a curvature of a human skull.

[0169] Embodiment 62. The implantable neurostimulation system of any one of embodiments 50-61, comprising the control circuit disposed within the INS housing and configured to generate electrical stimulation for brain tissue.

[0170] Embodiment 63. The implantable neurostimulation system of embodiment 62, comprising one or more electrodes electrically coupled to the control circuit and configured to provide the generated electrical stimulation to the brain tissue.

[0171] Embodiment 64. The implantable neurostimulation system of embodiment 63, comprising the one or more leads electrically connected to the control circuit, wherein the one or more electrodes are disposed on the one or more leads.

[0172] Embodiment 65. The implantable neurostimulation system of embodiment 63 or64, wherein the control circuit is configured to receive a command from an external device, the command configured to cause the control circuit to generate and provide the electrical stimulation to the brain tissue via the one or more electrodes.

[0173] Embodiment 66. The implantable neurostimulation system of embodiment 65, comprising a radio frequency (RF) antenna coupled to the control circuit such that the control circuit receives the command from RF waves emitted by the external device.

[0174] Embodiment 67. The implantable neurostimulation system of embodiment 65 or 66, wherein the control circuit is configured to communicate with the external device using radio wave backscatter.

[0175] Embodiment 68. The implantable neurostimulation system of any one of embodiments 65-67, comprising a radio frequency (RF) antenna coupled to the control circuit such that the control circuit receives energy from RF waves emitted by the external device.

[0176] Embodiment 69. The implantable neurostimulation system of any one of embodiments 66-68, wherein the RF antenna is configured to be implanted beneath the scalp external to the INS housing.

[0177] Embodiment 70. The implantable neurostimulation system of embodiment 65, comprising one or more ultrasonic transducers coupled to the control circuit such that the control circuit receives the command from ultrasonic waves emitted by the external device.

[0178] Embodiment 71. The implantable neurostimulation system of embodiment 65 or 70, wherein the control circuit is configured to communicate with the external device using ultrasonic backscatter.

[0179] Embodiment 72. The implantable neurostimulation system of any one of embodiments 65, 70, or 71, comprising one or more ultrasonic transducers coupled to the control circuit such that the control circuit receives energy from ultrasonic waves emitted by the external device.

[0180] Embodiment 73. The implantable neurostimulation system of any one of embodiments 70-72, wherein the one or more ultrasonic transducers are configured to be disposed within the INS housing.

[0181] Embodiment 74. The implantable neurostimulation system of any one of embodiments 62-73, comprising a power source electrically coupled to the control circuit and configured to be disposed within the INS housing.

[0182] Embodiment 75. The implantable neurostimulation system of embodiment 74, wherein the power source is a rechargeable battery.

[0183] Embodiment 76. An implantable neurostimulation system, comprising: the implantable neurostimulation system of any one of embodiments 62-75; and an external device configured to communicate with the implantable neurostimulator.

[0184] Embodiment 77. A method for stimulating brain tissue, comprising: providing energy to the implantable neurostimulator of any one of embodiments 62-76; and stimulating the brain tissue using electrical stimulation generated by the control circuit and provided to the brain tissue via one or more electrodes electrically coupled to the control circuit.

[0185] Embodiment 78. A method for assembling the implantable neurostimulation system of any one of embodiments 50-77, comprising: inserting a control circuit into the INS housing; enclosing the control circuit within the INS housing; and attaching the INS housing to the cradle configured to be implanted in the opening in the human skull.

[0186] Embodiment 79. The method of embodiment 78, wherein the INS housing comprises a first enclosure portion and a second enclosure portion, and enclosing the controlcircuit within the INS housing comprises attaching the first enclosure portion and the second enclosure portion.

[0187] Embodiment 80. The method of embodiment 78 or 79, comprising, prior to enclosing the control circuit within the INS housing, electrically connecting a power source to the control circuit.

[0188] Embodiment 81. The method of embodiment 80, wherein enclosing the control circuit within the INS housing encloses the power source in the INS housing.

[0189] Embodiment 82. The method of any one of embodiments 78-81, comprising attaching a header portion of the INS housing comprising a lead connection port to a side of the first enclosure portion and / or the second enclosure portion.

[0190] Embodiment 83. The method of embodiment 82, comprising coupling a lead connector to the lead connection port.

[0191] Embodiment 84. The method of any one of embodiments 78-83, comprising placing the INS housing in the cradle after the cradle is implanted in the opening of the human skull.

[0192] Embodiment 85. The method of any one of embodiments 78-84, wherein attaching the INS housing to the cradle comprises connecting one or more attachment portions of the INS housing with one or more corresponding attachment portions of the cradle.

[0193] Embodiment 86. A method for implanting an implantable neurostimulator (INS) in a human skull, comprising: removing a portion of the human skull to create an opening in the human skull sized to receive a cradle for retaining an INS; and implanting the cradle in the opening in the human skull such that an external surface of the INS is flush with a surface of the human skull.

[0194] Embodiment 87. The method of embodiment 86, wherein the external surface of the INS has a curved profile corresponding to a curvature of the surface of the human skull.

[0195] Embodiment 88. The method of embodiment 86 or 87, wherein the method comprises generating a burr hole in the human skull proximate to the opening for the cradle.

[0196] Embodiment 89. The method of embodiment 88, comprising implanting one or more leads into brain tissue through the burr hole.

[0197] Embodiment 90. The method of embodiment 86 or 87, wherein, prior to inserting the cradle into the opening in the human skull, the method comprises implanting one or more leads into brain tissue through the opening.

[0198] Embodiment 91. The method of embodiment 89 or 90, comprising electrically connecting the one or more leads to a lead connector of the INS.

[0199] Embodiment 92. The method of embodiment 91, wherein the lead connector is electrically connected to a control circuit enclosed within the INS such that connecting the one or more leads to the lead connector electrically connects the one or more leads to the control circuit.

[0200] Embodiment 93. The method of embodiment 92, wherein the lead connector is housed in a header portion of the INS.

[0201] Embodiment 94. The method of any one of embodiments 86-93, wherein creating the opening in the human skull comprises tracing an outline of a cutting template on the human skull, wherein a profile of the cutting template corresponds with the curved profile of the cradle.

[0202] Embodiment 95. The method of any one of embodiments 86-94, comprising attaching the cradle to the human skull at one or more external attachment portions of the cradle.

[0203] Embodiment 96. The method of any one of embodiments 86-95, comprising removably attaching the INS to the cradle at one or more attachment portions of the INS that correspond to one or more internal attachment portions of the cradle.

[0204] Embodiment 97. A method for replacing an implantable neurostimulator (INS) implanted in the human skull, comprising: removing the INS from a cradle implanted in the human skull; disconnecting one or more leads implanted in brain tissue from the INS; electrically connecting the one or more leads to a replacement INS; and inserting the replacement INS into the cradle implanted in the human skull.

[0205] Embodiment 98. The method of embodiment 97, wherein the method does not comprise removing the cradle from the human skull.

[0206] Embodiment 99. The method of embodiment 97 or 98, wherein removing the INS from the cradle implanted in the human skull comprises detaching an INS housing of the INS from the cradle at one or more attachment portions of the INS housing attached to one or more corresponding attachment portions of the cradle.

[0207] Embodiment 100. The method of any one of embodiments 97-99, comprising replacing the one or more leads.

[0208] Embodiment 101. The method of embodiment 100, wherein replacing the one or more leads comprises removing the one or more leads from the brain tissue and implanting one or more replacement leads into the brain tissue.

[0209] Embodiment 102. The method of embodiment 101, wherein the one or more leads are implanted into the brain tissue through a burr hole in the human skull proximate to the INS implanted in the human skull, such that removing the one or more leads and implanting the one or more replacement leads occurs through the burr hole.

[0210] Embodiment 103. The method of embodiment 101, wherein the one or more leads are implanted into the brain tissue through an opening in a bottom surface of the cradle, such that removing the one or more leads and implanting the one or more replacement leads occurs through the opening in the bottom surface of the cradle.

[0211] Embodiment 104. The method of any one of embodiments 100-103, wherein electrically connecting the one or more leads to the replacement INS comprises electrically connecting the one or more replacement leads to the replacement INS.

[0212] Embodiment 105. The method of any one of embodiments 97-104, comprising cutting and retracting a portion of the scalp corresponding to a location of the implanted INS.

[0213] Embodiment 106. The method of embodiment 105, comprising replacing the portion of the scalp after inserting the replacement INS into the cradle.

[0214] Embodiment 107. The method of any one of embodiments 97-106, wherein the method does not comprise resecting the human skull.

[0215] Embodiment 108. A method for performing an imaging procedure on a human having an implantable neurostimulator (INS) implanted in the skull of the human, comprising: removing the INS from a cradle implanted in the human skull; disconnecting one or more leads implanted in brain tissue from the INS; performing the imaging procedure on the human; reconnecting the one or more leads implanted in the brain tissue to the INS; and reinserting the INS into the cradle implanted in the human skull.

[0216] Embodiment 109. The method of embodiment 108, wherein the method does not comprise removing the cradle from the human skull.

[0217] Embodiment 110. The method of embodiment 108 or 109, wherein the imaging procedure images at least a portion of the brain of the subject.

[0218] Embodiment 111. The method of any one of embodiments 108-110, wherein the imaging procedure is a magnetic resonance imaging (MRI) procedure on the brain.

[0219] Embodiment 112. The method of any one of embodiments 108-111, comprising inserting a nonconductive body into the cradle prior to performing the imaging procedure.

[0220] Embodiment 113. The method of embodiment 112, wherein a profile of the nonconductive body mimics a profile of the cradle.

[0221] Embodiment 114. The method of any one of embodiments 108-113, comprising cutting and retracting a portion of the scalp corresponding to a location of the implanted INS.

[0222] Embodiment 115. The method of embodiment 114, comprising replacing the portion of the scalp prior to performing the imaging procedure.

[0223] Embodiment 116. The method of embodiment 114 or 115, comprising replacing the portion of the scalp after inserting the reinserting the INS into the cradle.

[0224] Embodiment 117. The method of any one of embodiments 108-116, wherein the method does not comprise resecting the human skull.

[0225] Embodiment 118. The method of embodiment 17 or 18, wherein the control circuit is configured to communicate with the external device using active radio wave transmission.

[0226] Embodiment 119. The method of embodiment 17 or 22, wherein the control circuit is configured to communicate with the external device using active ultrasonic wave transmission.

[0227] Embodiment 120. The implantable neurostimulation system of embodiment 65 or 66, wherein the control circuit is configured to communicate with the external device using active radio wave transmission.

[0228] Embodiment 121. The implantable neurostimulation system of embodiment 65 or 70, wherein the control circuit is configured to communicate with the external device using active ultrasonic wave transmission.Conclusion

[0229] The foregoing description, for the purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the techniques and their practical applications. Others skilled in the art are thereby enabled to best utilize the techniques and various embodiments with various modifications as are suited to the particular use contemplated.

[0230] Although the disclosure and examples have been fully described with reference to the accompanying figures, it is to be noted that various changes and modifications willbecome apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosure and examples as defined by the claims.

Claims

CLAIMSWhat is claimed is:

1. An implantable neurostimulator (INS) housing, comprising: a lead connection port configured to receive one or more leads of an implantable neurostimulator; and a first enclosure portion and a second enclosure portion configured to attach to the first enclosure portion to enclose a control circuit for controlling brain neurostimulation, wherein at least one of the first enclosure portion and the second enclosure portion comprises an external surface having a curved profile corresponding to a curvature of a human skull.

2. The INS housing of claim 1, wherein the curved profile of the external surface comprises a constant spherical radius, a plurality of curvatures, or one or more non-uniform curvatures.

3. The INS housing of claim 1 or 2, wherein the curved profile of the external surface comprises a radius between 80 mm and 140 mm.

4. The INS housing of any one of claims 1-3, wherein a shape of the INS housing comprises an obround profile.

5. The INS housing of any one of claims 1-4, wherein the first enclosure portion and the second enclosure portion are configured to hermetically seal to enclose the control circuit.

6. The INS housing of any one of claims 1-5, comprising a header portion that comprises the lead connection port and an external surface having the curved profile corresponding to a curvature of a human skull.

7. The INS housing of any one of claims 1-6, comprising one or more external attachment portions extending from the first enclosure portion and / or the second enclosure portion and configured to attach the INS housing to the human skull.

8. The INS housing of any one of claims 1-7, wherein a bottom surface of the first enclosure portion is configured to attach to a top surface of the second enclosure portion,such that a top surface of the first enclosure portion comprises the external surface having the curved profile corresponding to a curvature of a human skull.

9. The INS housing of any one of claims 1-7, wherein a side surface of the first enclosure portion is configured to attach to a side surface of the second enclosure portion, such that each of the first enclosure portion and the second enclosure portion comprises at least a portion of the external surface having the curved profile corresponding to a curvature of a human skull.

10. An implantable neurostimulation system, comprising: the INS housing of any one of claims 1-9; and a cradle configured to be implanted within the human skull and receive the INS housing.

11. The implantable neurostimulation system of claim 10, wherein the INS housing comprises one or more attachment portions that removably secure the INS housing to the cradle.

12. The implantable neurostimulation system of claim 10 or 11, wherein the cradle comprises one or more external attachment portions configured to attach the INS housing to the human skull.

13. The implantable neurostimulation system of any one of claims 10-12, wherein a bottom surface of the cradle comprises one or more openings operably connected to the lead connection port and configured to receive the one or more leads.

14. An implantable neurostimulator, comprising: the INS housing of any one of claims 1-13; and the control circuit disposed within the INS housing, the control circuit configured to generate electrical stimulation for brain tissue.

15. The implantable neurostimulator of claim 14, comprising one or more electrodes electrically coupled to the control circuit and configured to provide the generated electrical stimulation to the brain tissue.

16. The implantable neurostimulator of claim 15, comprising the one or more leads electrically connected to the control circuit, wherein the one or more electrodes are disposed on the one or more leads.

17. The implantable neurostimulator of claim 15 or 16, wherein the control circuit is configured to receive a command from an external device, the command configured to cause the control circuit to generate and provide the electrical stimulation to the brain tissue via the one or more electrodes.

18. The implantable neurostimulator of claim 17, comprising a radio frequency (RF) antenna coupled to the control circuit such that the control circuit receives the command from RF waves emitted by the external device.

19. The implantable neurostimulator of claim 17 or 18, wherein the control circuit is configured to communicate with the external device using radio wave backscatter.

20. The implantable neurostimulator of any one of claims 17-19, comprising a radio frequency (RF) antenna coupled to the control circuit such that the control circuit receives energy from RF waves emitted by the external device.

21. The implantable neurostimulator of any one of claims 18-20, wherein the RF antenna is configured to be implanted beneath the scalp external to the INS housing.

22. The implantable neurostimulator of claim 17, comprising one or more ultrasonic transducers coupled to the control circuit such that the control circuit receives the command from ultrasonic waves emitted by the external device.

23. The implantable neurostimulator of claim 17 or 22, wherein the control circuit is configured to communicate with the external device using ultrasonic backscatter.

24. The implantable neurostimulator of any one of claims 17, 22, or 23, comprising one or more ultrasonic transducers coupled to the control circuit such that the control circuit receives energy from ultrasonic waves emitted by the external device.

25. The implantable neurostimulator of any one of claims 22-24, wherein the one or more ultrasonic transducers are configured to be disposed within the INS housing.

26. The implantable neurostimulator of any one of claims 14-25, comprising a power source electrically coupled to the control circuit and configured to be disposed within the INS housing.

27. The implantable neurostimulator of claim 26, wherein the power source is a rechargeable battery.

28. An implantable neurostimulation system, comprising: the implantable neurostimulator of any one of claims 14-27; and an external device configured to communicate with the implantable neurostimulator.

29. A method for stimulating brain tissue, comprising: providing energy to the implantable neurostimulator of any one of claims 14-28; and stimulating the brain tissue using electrical stimulation generated by the control circuit and provided to the brain tissue via one or more electrodes electrically coupled to the control circuit.

30. A method for assembling an implantable neurostimulator (INS) contained in the INS housing of any one of claims 1-29, comprising: positioning a control circuit on an inner surface of the INS housing; and attaching a first enclosure portion of the INS housing and a second enclosure portion of the INS housing to enclose the control circuit within the INS housing.

31. The method of claim 30, comprising, prior to attaching the first enclosure portion and the second enclosure portion, electrically connecting a power source to the control circuit.

32. The method of claim 31, wherein attaching the first enclosure portion and the second enclosure portion encloses the power source within the INS housing.

33. The method of any one of claims 30-32, comprising attaching a header portion of the INS housing comprising the lead connection port to a side of the first enclosure portion and / or the second enclosure portion.

34. The method of claim 33, comprising coupling a lead connector to the lead connection port.

35. The method of any one of claims 30-34, comprising placing the INS housing in a cradle configured to be implanted in the human skull.

36. The method of claim 35, wherein placing the INS housing in the cradle occurs after the cradle is implanted in the human skull.

37. The method of claim 35 or 36, wherein placing the INS housing in the cradle comprises connecting one or more attachment portions of the INS housing with one or more corresponding attachment portions of the cradle.

38. A method for implanting an implantable neurostimulator (INS) in a human skull, comprising: removing a portion of the human skull to create an opening in the human skull sized to receive an INS housing; and inserting the INS housing into the opening in the human skull such that an external surface of the INS housing is flush with a surface of the human skull.

39. The method of claim 38, wherein the external surface of the INS housing comprises a curved profile corresponding to a curvature of the surface of the human skull.

40. The method of claim 38 or 39, wherein the method comprises generating a burr hole in the human skull proximate to the opening for the INS housing.

41. The method of claim 40, comprising implanting one or more leads into brain tissue through the burr hole.

42. The method of claim 38 or 39, wherein, prior to inserting the INS housing into the opening in the human skull, the method comprises implanting one or more leads into brain tissue through the opening.

43. The method of claim 41 or 42, comprising electrically connecting the one or more leads to a lead connector within the INS housing.

44. The method of claim 43, wherein the lead connector is electrically connected to a control circuit enclosed within the INS housing such that connecting the one or more leads to the lead connector electrically connects the one or more leads to the control circuit.

45. The method of claim 43 or 44, wherein the lead connector is housed in a header portion of the INS housing.

46. The method of any one of claims 38-45, wherein creating the opening in the human skull comprises tracing an outline of a cutting template on the human skull, wherein a profde of the cutting template corresponds with the shape of the INS housing.

47. The method of any one of claims 38-46, comprising attaching the INS housing to the human skull at one or more external attachment portions of the INS housing.

48. The method of any one of claims 38-46, comprising implanting a cradle configured to receive the INS housing into the opening in the human skull and attaching the cradle to the human skull at one or more external attachment portions of the cradle.

49. The method of claim 48, comprising removably attaching the INS housing to the cradle at one or more attachment portions of the INS housing that correspond to one or more internal attachment portions of the cradle.

50. An implantable neurostimulation system, comprising: an implantable neurostimulator (INS) comprising an INS housing configured to enclose a control circuit for controlling brain neurostimulation; and a cradle configured to be implanted in an opening in a human skull and to receive the INS housing.

51. The implantable neurostimulation system of claim 50, wherein the cradle is configured to be implanted in the opening of the human skull such that an external surface of the INS housing is flush with a surface of the human skull when the INS housing is disposed in the cradle.

52. The implantable neurostimulation system of claim 51, wherein the external surface of the INS housing has a curved profile corresponding to a curvature of the human skull.

53. The implantable neurostimulation system of any one of claims 50-52, wherein the cradle comprises one or more internal attachment portions configured to removably secure the INS housing to the cradle.

54. The implantable neurostimulation system of any one of claims 50-53, wherein the cradle comprises one or more external attachment portions configured to attach the cradle to the human skull.

55. The implantable neurostimulation system of claim 54, wherein the one or more external attachment portions extend from an upper edge of the cradle.

56. The implantable neurostimulation system of any one of claims 50-55, wherein a shape of the INS housing comprises an obround profile.

57. The implantable neurostimulation system of claim 56, wherein a shape of the cradle comprises an obround profile corresponding to the profile of the INS housing.

58. The implantable neurostimulation system of any one of claims 50-57, wherein the INS housing comprises a lead connection port configured to receive one or more leads of the INS, a first enclosure portion, and a second enclosure portion configured to attach to the first enclosure portion to enclose the control circuit.

59. The implantable neurostimulation system of claim 58, wherein the first enclosure portion and / or the second enclosure portion comprises the external surface having a curved profile corresponding to a curvature of a human skull.

60. The implantable neurostimulation system of claim 58 or 59, wherein the first enclosure portion and the second enclosure portion attach are configured to hermetically seal to enclose the control circuit.

61. The implantable neurostimulation system of any one of claims 58-60, comprising a header portion that comprises the lead connection port and an external surface having the curved profile corresponding to a curvature of a human skull.

62. The implantable neurostimulation system of any one of claims 50-61, comprising the control circuit disposed within the INS housing and configured to generate electrical stimulation for brain tissue.

63. The implantable neurostimulation system of claim 62, comprising one or more electrodes electrically coupled to the control circuit and configured to provide the generated electrical stimulation to the brain tissue.

64. The implantable neurostimulation system of claim 63, comprising the one or more leads electrically connected to the control circuit, wherein the one or more electrodes are disposed on the one or more leads.

65. The implantable neurostimulation system of claim 63 or 64, wherein the control circuit is configured to receive a command from an external device, the command configured to cause the control circuit to generate and provide the electrical stimulation to the brain tissue via the one or more electrodes.

66. The implantable neurostimulation system of claim 65, comprising a radio frequency (RF) antenna coupled to the control circuit such that the control circuit receives the command from RF waves emitted by the external device.

67. The implantable neurostimulation system of claim 65 or 66, wherein the control circuit is configured to communicate with the external device using radio wave backscatter.

68. The implantable neurostimulation system of any one of claims 65-67, comprising a radio frequency (RF) antenna coupled to the control circuit such that the control circuit receives energy from RF waves emitted by the external device.

69. The implantable neurostimulation system of any one of claims 66-68, wherein the RF antenna is configured to be implanted beneath the scalp external to the INS housing.

70. The implantable neurostimulation system of claim 65, comprising one or more ultrasonic transducers coupled to the control circuit such that the control circuit receives the command from ultrasonic waves emitted by the external device.

71. The implantable neurostimulation system of claim 65 or 70, wherein the control circuit is configured to communicate with the external device using ultrasonic backscatter.

72. The implantable neurostimulation system of any one of claims 65, 70, or 71, comprising one or more ultrasonic transducers coupled to the control circuit such that the control circuit receives energy from ultrasonic waves emitted by the external device.

73. The implantable neurostimulation system of any one of claims 70-72, wherein the one or more ultrasonic transducers are configured to be disposed within the INS housing.

74. The implantable neurostimulation system of any one of claims 62-73, comprising a power source electrically coupled to the control circuit and configured to be disposed within the INS housing.

75. The implantable neurostimulation system of claim 74, wherein the power source is a rechargeable battery.

76. An implantable neurostimulation system, comprising: the implantable neurostimulation system of any one of claims 62-75; and an external device configured to communicate with the implantable neurostimulator.

77. A method for stimulating brain tissue, comprising: providing energy to the implantable neurostimulator of any one of claims 62-76; andstimulating the brain tissue using electrical stimulation generated by the control circuit and provided to the brain tissue via one or more electrodes electrically coupled to the control circuit.

78. A method for assembling the implantable neurostimulation system of any one of claims 50-77, comprising: inserting a control circuit into the INS housing; enclosing the control circuit within the INS housing; and attaching the INS housing to the cradle configured to be implanted in the opening in the human skull.

79. The method of claim 78, wherein the INS housing comprises a first enclosure portion and a second enclosure portion, and enclosing the control circuit within the INS housing comprises attaching the first enclosure portion and the second enclosure portion.

80. The method of claim 78 or 79, comprising, prior to enclosing the control circuit within the INS housing, electrically connecting a power source to the control circuit.

81. The method of claim 80, wherein enclosing the control circuit within the INS housing encloses the power source in the INS housing.

82. The method of any one of claims 78-81, comprising attaching a header portion of the INS housing comprising a lead connection port to a side of the first enclosure portion and / or the second enclosure portion.

83. The method of claim 82, comprising coupling a lead connector to the lead connection port.

84. The method of any one of claims 78-83, comprising placing the INS housing in the cradle after the cradle is implanted in the opening of the human skull.

85. The method of any one of claims 78-84, wherein attaching the INS housing to the cradle comprises connecting one or more attachment portions of the INS housing with one or more corresponding attachment portions of the cradle.

86. A method for implanting an implantable neurostimulator (INS) in a human skull, comprising: removing a portion of the human skull to create an opening in the human skull sized to receive a cradle for retaining an INS; and implanting the cradle in the opening in the human skull such that an external surface of the INS is flush with a surface of the human skull.

87. The method of claim 86, wherein the external surface of the INS has a curved profde corresponding to a curvature of the surface of the human skull.

88. The method of claim 86 or 87, wherein the method comprises generating a burr hole in the human skull proximate to the opening for the cradle.

89. The method of claim 88, comprising implanting one or more leads into brain tissue through the burr hole.

90. The method of claim 86 or 87, wherein, prior to inserting the cradle into the opening in the human skull, the method comprises implanting one or more leads into brain tissue through the opening.

91. The method of claim 89 or 90, comprising electrically connecting the one or more leads to a lead connector of the INS.

92. The method of claim 91, wherein the lead connector is electrically connected to a control circuit enclosed within the INS such that connecting the one or more leads to the lead connector electrically connects the one or more leads to the control circuit.

93. The method of claim 92, wherein the lead connector is housed in a header portion of the INS.

94. The method of any one of claims 86-93, wherein creating the opening in the human skull comprises tracing an outline of a cutting template on the human skull, wherein a profde of the cutting template corresponds with the curved profde of the cradle.

95. The method of any one of claims 86-94, comprising attaching the cradle to the human skull at one or more external attachment portions of the cradle.

96. The method of any one of claims 86-95, comprising removably attaching the INS to the cradle at one or more attachment portions of the INS that correspond to one or more internal attachment portions of the cradle.

97. A method for replacing an implantable neurostimulator (INS) implanted in the human skull, comprising: removing the INS from a cradle implanted in the human skull; disconnecting one or more leads implanted in brain tissue from the INS; electrically connecting the one or more leads to a replacement INS; and inserting the replacement INS into the cradle implanted in the human skull.

98. The method of claim 97, wherein the method does not comprise removing the cradle from the human skull.

99. The method of claim 97 or 98, wherein removing the INS from the cradle implanted in the human skull comprises detaching an INS housing of the INS from the cradle at one or more attachment portions of the INS housing attached to one or more corresponding attachment portions of the cradle.

100. The method of any one of claims 97-99, comprising replacing the one or more leads.

101. The method of claim 100, wherein replacing the one or more leads comprises removing the one or more leads from the brain tissue and implanting one or more replacement leads into the brain tissue.

102. The method of claim 101, wherein the one or more leads are implanted into the brain tissue through a burr hole in the human skull proximate to the INS implanted in the human skull, such that removing the one or more leads and implanting the one or more replacement leads occurs through the burr hole.

103. The method of claim 101, wherein the one or more leads are implanted into the brain tissue through an opening in a bottom surface of the cradle, such that removing the one or more leads and implanting the one or more replacement leads occurs through the opening in the bottom surface of the cradle.

104. The method of any one of claims 100-103, wherein electrically connecting the one or more leads to the replacement INS comprises electrically connecting the one or more replacement leads to the replacement INS.

105. The method of any one of claims 97-104, comprising cutting and retracting a portion of the scalp corresponding to a location of the implanted INS.

106. The method of claim 105, comprising replacing the portion of the scalp after inserting the replacement INS into the cradle.

107. The method of any one of claims 97-106, wherein the method does not comprise resecting the human skull.

108. A method for performing an imaging procedure on a human having an implantable neurostimulator (INS) implanted in the skull of the human, comprising: removing the INS from a cradle implanted in the human skull; disconnecting one or more leads implanted in brain tissue from the INS; performing the imaging procedure on the human; reconnecting the one or more leads implanted in the brain tissue to the INS; and reinserting the INS into the cradle implanted in the human skull.

109. The method of claim 108, wherein the method does not comprise removing the cradle from the human skull.

110. The method of claim 108 or 109, wherein the imaging procedure images at least a portion of the brain of the subject.

111. The method of any one of claims 108-110, wherein the imaging procedure is a magnetic resonance imaging (MRI) procedure on the brain.

112. The method of any one of claims 108-111, comprising inserting a nonconductive body into the cradle prior to performing the imaging procedure.

113. The method of claim 112, wherein a profde of the nonconductive body mimics a profde of the cradle.

114. The method of any one of claims 108-113, comprising cutting and retracting a portion of the scalp corresponding to a location of the implanted INS.

115. The method of claim 114, comprising replacing the portion of the scalp prior to performing the imaging procedure.

116. The method of claim 114 or 115, comprising replacing the portion of the scalp after reinserting the INS into the cradle.

117. The method of any one of claims 108-116, wherein the method does not comprise resecting the human skull.

118. The method of claim 17 or 18, wherein the control circuit is configured to communicate with the external device using active radio wave transmission.

119. The method of claim 17 or 22, wherein the control circuit is configured to communicate with the external device using active ultrasonic wave transmission.

120. The implantable neurostimulation system of claim 65 or 66, wherein the control circuit is configured to communicate with the external device using active radio wave transmission.

121. The implantable neurostimulation system of claim 65 or 70, wherein the control circuit is configured to communicate with the external device using active ultrasonic wave transmission.

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