Cranial Access Devices

Abstract

The present disclosure provides a cranial access device that reduces or eliminates artifacts during imaging. The cranial access device includes a skull bolt and a drive adapter. The skull bolt includes a distal threaded portion, a proximal drive portion with a plurality of protrusions forming an external drive geometry, and a central passage configured to receive a neurosurgical tool. The drive adapter includes a distal end configured to receive and interact with the external drive geometry of the proximal drive portion, and a proximal end configured to receive a driver tool.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to devices and methods for gaining access to the interior of the human and animal brain. In particular, the present disclosure relates to skull bolts or screws for fastening medical devices to the skull and for providing access to the interior of the skull, and methods of their operation. [Background technology]

[0002] (Background to the disclosure) Cranial access devices, such as skull bolts, are used to secure medical devices to the head and to control the depth and / or trajectory of such medical devices inserted into the skull and into the brain. Medical devices can include, for example, catheters, neurosurgical tools, probe drivers or probes. The medical devices are introduced into lumens or holes in the access device and into corresponding holes in the skull.

[0003] A medical device is secured to the skull by screwing a cranial access device into the skull and then attaching or coupling the medical device to the cranial access device. For example, an interventional procedure on a subject's brain may involve drilling a burr hole into the subject's skull, fitting a cranial access device onto the subject's skull, and guiding an instrument (e.g., a catheter, needle, cannula, electrode or other device) through the cranial access device to a desired target within the subject, for example, in an image-guided procedure, by using preoperative or live images from imaging (e.g., MR, CT, PET, ultrasound, etc.). Precise guidance may be desirable, and millimeter or sub-millimeter accuracy of instrument location may be desirable, especially for interventional procedures on the brain. However, current access devices are made from conductive metals, including metals (e.g., titanium) that can induce artifacts during imaging (e.g., magnetic resonance imaging (MRI), thermography, etc.), especially when used during treatment of shallow targets, such as less than 20 mm from the skull surface. This impacts the surgeon's ability to visualize the medical device and / or image-guided therapy during treatment.

[0004] The present disclosure describes devices and methods directed to solving some of the problems noted above. Summary of the Invention [Means for solving the problem]

[0005] Disclosed scenarios provide a cranial access device that reduces or eliminates artifacts during imaging. The cranial access device includes a cranial bolt or drive adapter. The cranial bolt may include a distal threaded portion with an external drive geometry configured to receive a neurosurgical tool and a plurality of protrusions forming a central passage, a proximal drive. The drive adapter may include a distal end configured to receive and interact with the external drive geometry of the proximal drive, and a proximal end configured to receive a driver tool. In some scenarios, a kit for use in neurosurgery is disclosed that includes a cranial access device and a driver tool, the driver tool being inserted into the cranial access device, the cranial access device providing a continuous lumen for insertion into a stereotactic device during a surgical procedure.

[0006] Optionally, the skull bolt is manufactured using a non-conductive, rigid material that substantially reduces the formation of artifacts during magnetic resonance imaging, such as, but not limited to, ceramic.

[0007] In one or more embodiments, the drive adapter can be manufactured using a semi-rigid material, such as, but not limited to, plastic.

[0008] In various scenarios, the distal threaded portion may be configured for self-tapping of the skull bolt into the skull hole, in such scenarios, the distal threaded portion may include a distal end that does not include threads.

[0009] In various embodiments, the cranial access device may also include at least one reduced diameter tube for modifying the diameter of the central passageway.

[0010] Optionally, the central passage may be further configured to receive at least a portion of a drive pin of a drive tool.

[0011] Additionally and / or alternatively, a first outer diameter of a portion of the skull bolt between the proximal drive portion and the distal threaded portion can be substantially equal to an outer diameter of the drive adapter. In such embodiments, a second outer diameter of a second portion of the skull bolt between the proximal drive portion and the distal threaded portion can be smaller than the first outer diameter.

[0012] Optionally, the torque tolerance of the drive adapter may be less than the torque tolerance of the skull bolt. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an elevational view of a cranial access device of the present invention mounted to a patient's skull.

[0014] [Diagram 2] Figure 2A illustrates an exemplary skull bolt of the cranial access device of Figure 1. Figure 2B is a cross-sectional view of a threaded portion of the skull bolt of Figure 2A.

[0015] [Diagram 3] FIG. 3 is an enlarged view of the threaded portion of the skull bolt of FIG. 2A.

[0016] [Figure 4-1] FIG. 4A illustrates a compressive force for an externally driven geometry, and FIG. 4B illustrates an attractive force for an internally driven geometry.

[0017] [Figure 4-2] FIG. 4C illustrates an example external drive geometry.

[0018] [Figure 5A] 5A illustrates an exemplary drive adapter of the cranial access device of FIG. 1.

[0019] [Figure 5B] 5B illustrates a cross-sectional view of the distal end of the drive adapter of FIG. 5A, and FIG. 5C illustrates a cross-sectional view of the proximal end of the drive adapter of FIG. 5A.

[0020] [Figure 6] FIG. 6 illustrates an exemplary driver tool before and after being coupled to a cranial access device including a ceramic bolt and drive adapter. [Figure 6-1] 6 illustrates an exemplary driver tool before and after coupling to a cranial access device including a ceramic bolt and drive adapter.

[0021] [Figure 7A] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7A-1] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7A-2] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7A-3] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7A-4] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7B]FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7B-1] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7B-2] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7B-3] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. [Figure 7B-4] FIG. 7A illustrates artifacts induced in an image with a metallic skull bolt, and FIG. 7B illustrates an image with a skull bolt of the present disclosure with substantially reduced or no artifacts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] BRIEF DESCRIPTION OF THE DISCLOSED EMBODIMENTS The devices and methods of the present disclosure may be more readily understood by reference to the following detailed description of the embodiments taken in conjunction with the accompanying drawings, which form a part of this disclosure. It should be understood that the present application is not limited to the specific devices, methods, conditions or parameters described and / or illustrated herein, and that the terminology used herein is for the purpose of describing specific embodiments by way of example only, and is not intended to be limiting. In some embodiments, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include the plural, and reference to a particular numerical value includes at least that particular value, unless the context expressly dictates otherwise. Ranges may be expressed as "about" or "approximately" from one particular value and / or to "about" or "approximately" the other particular. When such ranges are expressed, other embodiments include from one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, it will be understood that the particular value forms another embodiment by use of the antecedent "about." It will also be understood that all spatial references, such as, for example, proximal, distal, horizontal, vertical, top, upper, lower, down, left and right, are for illustrative purposes only and can be varied within the scope of this disclosure. For example, references to "upper" and "lower" are used only in the context of others and not necessarily "superior" and "inferior." It should be noted that the terms "proximal" and "distal" as used herein are intended to refer to directions toward (proximal) and away from (distal) the surgeon or other user of the device.

[0023] Although the examples provided in this disclosure relate generally to bolts or screws for cranial access, the disclosed systems and methods of the present disclosure may be used for any other bone where it is desirable to pass a catheter or other similar device (including but not limited to the spinal cord, hip joint, etc.) For example, the disclosed embodiments may be used for access to the vertebral bodies of the spinal cord without departing from the principles disclosed herein.

[0024] Skull bolts are commonly utilized in holes (e.g., burr holes, twist holes, etc.) in a patient's skull for subsequent placement of medical devices (e.g., catheters, electrodes, neurosurgical tools, probe drivers, probes, etc.). The skull bolts of the present disclosure provide artifact-free and / or substantially artifact-free visualization of (1) the medical device(s), (2) the medical device trajectory (e.g., using fiducial markers without penetrating tissue), (3) image-guided therapy in the vicinity of the medical device, and / or tissue in the vicinity of the medical device during neurosurgical procedures as well as other imaging procedures. The embodiments may be used with newly designed dedicated medical devices or systems or with existing systems. For example, the embodiments may be used with medical devices or systems similar to those shown in U.S. Patent Application Nos. 9,510,909 and 10,327,830, the disclosures of which are incorporated herein by reference in their entireties.

[0025] The devices and methods disclosed herein aim to improve at least one of the problems mentioned above. However, it should be understood that the disclosure herein is not limited to merely solving these particular problems. In addition, although the devices and techniques disclosed herein are described in relation to human bodies or patients, the devices and techniques may be applied to non-human patients (i.e., in veterinary medicine) in suitable circumstances.

[0026] In various implementations, the present disclosure describes a cranial access device including a skull bolt and a drive adapter assembly. The skull bolt is manufactured using a non-conductive (e.g., non-conductive) material that does not introduce artifacts (and / or introduces minimal artifacts) during imaging, such as, but not limited to, ceramic, fiberglass, plastic, glass-filled polymer, and the like. Additionally, the material may be chosen such that it is harder than bone, allowing for self-tapping of the skull bolt. The skull bolt is configured to be inserted into a hole formed in the subject's skull, allowing a medical device to access the cranial cavity through the skull bolt. Typically, the hole is drilled into the patient's skull using a twist drill, and the threaded portion of the skull bolt is screwed directly into the hole. Other prior art bolts may require an additional step of tapping or threading the hole to provide threads in the skull so that the prior art bolt can engage the skull. The skull bolt of the present application, however, does not require an additional step of tapping the hole, since it is self-tapping. Ceramic skull bolts may present an increased risk of fracture when driven by a tool during insertion into the skull hole due to low compliance between the two materials increasing point load stress concentrations. The drive adapter of the present disclosure is configured to provide an interface between a drive tool and the skull bolt during insertion of the skull bolt in the skull hole by engaging the proximal end of the skull bolt, for example, by distributing the load between the drive adapter and the skull interface, improving the fracture resistance of the skull bolt. Optionally, the drive adapter may also be configured to act as a torque limiter such that the drive adapter breaks (e.g., fractures) before the torque tolerance of the skull bolt is achieved during insertion.

[0027] A medical device can be guided through the continuous lumen (having a uniform diameter, graduated diameter, etc.) of the skull bolt and the drive adapter to access into the subject's skull. For example, the end of the bolt is sized to receive an instrument for neurosurgical intervention, and the instrument for neurosurgical intervention can access the target tissue through the distal end of the bolt (with or without the drive adapter attached thereto). Optionally, the proximal end of the bolt is sized so that multiple bolts can be positioned in close proximity to each other. The distal end of the bolt is designed such that the internal opening (i.e., internal diameter) at the distal end of the bolt receives various instruments. In addition, the outer diameter of the distal end of the bolt can be configured to prevent damage to the skull and minimize the diameter of the drill hole in the subject's skull.

[0028] Referring now to the drawings, and in particular to FIGS. 1-6, an exemplary cranial access device 10 is shown and described. Cranial access device 10 can be used to facilitate access of a medical device to a subject's cranial cavity. Specifically, cranial access device 10 is a rigid skull fixation device designed to provide a suitable platform for inserting, mounting, or otherwise coupling a medical device or instrument within a subject. Referring to FIG. 1, cranial access device 10, including skull bolt 100 and drive adapter 101, is shown secured to a patient's skull 200 in accordance with the present disclosure.

[0029] As shown in FIG. 2A, the skull bolt 100 includes a distal threaded portion 102 and a proximal non-threaded portion 104. A central passage 110 extends through the length of the skull bolt 100 (i.e., between the distal end and the opposite proximal end) and is illustrated as having a circular cross-section, but can be any shape, e.g., triangular, square, hexagonal, pentagonal (not shown). Additionally, as shown in FIG. 2B, the central passage 110 has a uniform diameter or width throughout its length. Although not shown in FIG. 2B, the diameter of the central passage may be graduated and / or increase uniformly from the distal end to the proximal end. Although the skull bolt is illustrated as a one-piece construction, it may optionally include two or more pieces joined together.

[0030] 3, the threaded portion 102 has an outer surface 121 with a plurality of threads 122 for engaging a hole 201 formed in the skull 200 for fixedly engaging (by self-tapping) the threaded portion 102 to the skull 200. Typically, the hole is drilled into the patient's skull using a twist drill. In one optional embodiment, the hole 201 is tapped or threaded to provide threads for the threaded portion 102 to engage the skull. In various other embodiments, the threaded portion 102 and threads 122 are self-tapping and do not require the additional step of tapping the hole 201. For example, the self-tapping threaded portion 102 includes a tapered thread configured to initiate threading and then draw the bolt into the hole 201. Optionally, the self-tapping capability can be created by cutting gaps in the thread sequence to create grooves and cutting edges. The self-tapping screw portion 102 reduces the number of steps required and reduces the amount of time required for a given procedure.

[0031] Optionally, the distal tip of threaded portion 102 may be tapered or blunt to a diameter smaller than the lead thread diameter of threads 122 to aid in initial screw engagement with the skull and maintain the desired orbital alignment. This may be particularly useful for holes angled away from the vertical axis of the skull.

[0032] Additionally and / or alternatively, the distal end of the threaded portion 102 may not include any threads to provide the ability to insert the bolt into the subject's skull in a seamless manner (e.g., when the wall thickness of the threaded portion is too thin to use a fully threaded distal end). For example, the distal end of the threaded portion 102 (e.g., about 1 mm to about 5 mm, about 2 mm to about 4 mm, about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, etc., in length from the distal tip) may be unthreaded. The diameter of this unthreaded portion may be approximately equal to the root diameter of the threads 122. This allows the bolt to enter the drill hole slightly before the threads begin to engage. Restricting the tip portion of the bolt within the hole keeps the bolt aligned and improves the ability of the first thread to "catch". This helps maintain the desired trajectory and generally improves the ability to thread the bolt into the hole. Furthermore, when the trajectory of insertion of the bolt into the subject's skull is tilted relative to the skull surface, the bolt must be inserted into an angled hole where the threads are forced to "catch" (i.e., engage) the skull surface, thereby preparing the bolt to be screwed seamlessly into the skull. The distal tip of the unthreaded portion prepares for insertion of the bolt tip into such a hole, thereby guiding the bolt before the threaded portion engages the skull surface.

[0033] The bolt 100 is fabricated using a material that is harder than bone, is not electrically conductive, and / or does not introduce (or substantially reduces) artifacts during imaging (e.g., is non-ferrous and has low electrical conductivity), such as, but not limited to, ceramic, fiberglass, plastic, glass-filled polymer, etc. Exemplary ceramic compositions can include, but are not limited to, zirconia (yttria partially stabilized zirconia, hip-yttria partially stabilized zirconia, etc.), zirconia toughened alumina, alumina (AD-96%, ADO-96%, etc.), porcelain, steatite, cordierite, etc.

[0034] As shown in FIG. 2A, the unthreaded portion 104 may include a first cylindrical portion 141, a second cylindrical portion 142, and a driver portion 143. The first and second cylindrical portions 141 and 142 have relatively smooth outer surfaces, with the diameter of the outer surface of the second cylindrical portion 142 being larger than that of the first cylindrical portion 141. The change in diameter allows for the formation of a "shoulder" between the first cylindrical portion 141 and the second cylindrical portion 142 that promotes an edge for securely fastening a medical device (e.g., a probe or probe driver) to the bolt. The driver cross section 143 includes protrusions 145 that form an external driver geometry, for example, in the form of a sinusoidal pattern as shown in FIG. 4A. Ceramics and other similar materials tend to be weaker under tension than they are under compression. The external drive geometry allows the proximal end of the bolt 100 to be under compressive forces as shown in FIG. 4A (rather than tensile forces as shown in FIG. 4B) during installation and / or removal of the bolt 100 from the skull hole, thereby reducing the risk of breakage or failure of the bolt 100. In addition, the sinusoidal pattern may be selected to minimize sharp edges that can cause stress concentrations that lead to breakage or failure of the bolt 100. However, other patterns of the protrusions 145, such as a wave pattern with rounded lobes or protrusions around the edges of the central passage (the number of lobes can be 3, 4, 5, etc.), are within the scope of this disclosure. An example of such a pattern is shown as 420 in FIG. 4C.

[0035] Depending on the embodiment, the total length of the skull bolt 100 between the proximal and distal ends is about 35 mm to about 45 mm, about 37 mm to about 43 mm, about 38 mm to about 42 mm, about 40 mm, about 41 mm, about 42, etc. The length of the threaded portion 102 is about one-quarter to about one-half the length of the skull bolt, about one-quarter the length of the skull bolt, about one-third the length of the skull bolt, about one-half the length of the skull bolt, etc. The diameter of the central passage is about 1.5 to 4.5 mm, about 2 to 4 mm, about 3 mm, about 1.5 mm, about 2 mm, about 2.2 mm, about 2.5 mm, about 3 mm, about 3.3 mm, about 3.5 mm, about 4 mm, about 4.5 mm, etc. The outer diameter of the threaded portion 102 is about 5.5 mm to about 7 mm, about 5.7 mm to about 6.7 mm, about 6 mm to about 6.5 mm, about 5.5 mm, about 6 mm, about 6.3 mm, about 6.5 mm, about 6.8 mm, about 7 mm, etc. and the inner diameter of the threads 102 is about 3.5 mm to about 5.5 mm, about 4 mm to about 5 mm, about 4.2 mm to about 4.8 mm, about 3.5 mm, about 4 mm, about 4.2 mm, about 4.5 mm, about 4.8 mm, about 5 mm, about 5.5 mm, etc., and the pitch of the threads 102 is about 0.75 mm to about 1.5 mm, about 1 mm to about 1.25 mm, about 0.75 mm, about 1 mm, about 1.25 mm, about 1.5 mm, etc. (i) the outer surface diameter of the first cylindrical portion 141 is about 5 mm to about 6.5 mm, about 5.2 mm to about 6.3 mm, about 5.4 mm to about 6.1 mm, about 5.6 mm to about 5.9 mm, about 5 mm, about 6.5 mm, about 5.2 mm, about 6.3 mm, about 5.4 mm, about 6.1 mm, about 5.6 mm, about 5.7 mm, about 5.8 mm, about 5.9 mm, etc.; and (ii) the outer surface diameter of the second cylindrical portion 142 is about 7 mm to about 9.5 mm. , about 7.5 mm to about 9 mm, about 8 mm to about 8.5 mm, about 7 mm, about 7.5 mm, about 8 mm, about 8.5 mm, about 9 mm, etc., and (iii) the outer surface diameter of the drive portion 143 is about 5 mm to about 6.5 mm, about 5.2 mm to about 6.3 mm, about 5.4 mm to about 6.1 mm, about 5 mm, about 6.5 mm, about 5.2 mm, about 6.3 mm, about 5.4 mm, about 6.1 mm, about 5.8 mm, about 5.9 mm, about 6 mm, etc. It should be understood that each of the exemplary diameter dimensions set forth above may be varied so long as the resulting bolt is not inconsistent with the description herein.

[0036] Although not shown herein, the first cylindrical portion 141 and / or the second cylindrical portion 142 may include marked gradations. For example, the markings may indicate a scale in millimeters, whereby markings are provided for every millimeter. However, markings for other units of measurement, such as centimeters, inches, etc., are within the scope of this disclosure.

[0037] A medical device (e.g., a neurosurgical device such as a probe) can be inserted into the central passage 110 for access to a target tissue and held in place by friction, compression fit, or the like. For example, the central passage 110 of the bolt 100 is sized to receive an instrument or medical device for a neurosurgical intervention at a proximal end, and the instrument or medical device can access the target tissue through the distal end of the bolt 100. Optionally, for medical devices (e.g., biopsy needles, SEEG electrodes, catheters, etc.) that have a smaller diameter than that of the central passage 110 so that they cannot be held in place by friction or compression fit, the cranial access device 10 can include a reduced diameter tube configured to reduce the diameter of the central passage for receiving the medical device by insertion into the central passage 110. The internal diameter of the reduced diameter tube can be configured to receive the medical device. Optionally, a sealing gasket may be associated with the exterior (e.g., proximal end) of the reduced diameter tube to minimize leakage of fluids (e.g., cerebrospinal fluid) and / or to maintain a desired position of the inserted medical device. The reduced diameter tube may also be made from a non-conductive material that exhibits minimal artifacts during imaging, such as, but not limited to, ceramic, fiberglass, plastic, etc.

[0038] The proximal end of the bolt is sized so that multiple bolts can be positioned adjacent to one another. The distal end of the bolt is designed with an internal opening (i.e., diameter of the central passage at the distal end) so that the distal end can receive an instrument having a diameter dimension of about 4-5 mm or less. However, the disclosure is not so limited and larger central passage diameters are within the range (e.g., up to about 14 mm). According to an embodiment, the threaded portion 204 of the bolt 200 can be sized to self-tap into a hole having a diameter of about 3 mm to about 8 mm, about 4 mm to about 7 mm, about 5 mm to about 6 mm, about 3 mm, about 3.5 mm, about 4.5 mm, about 5.5 mm, about 6 mm, about 6.5 mm, about 7 mm, about 8 mm, etc.

[0039] 5A, the drive adapter 101 engages the drive section 143 at the proximal end of the skull bolt 100 and provides an interface between the driver tool 600 and the cap bolt 100 during insertion of the skull bolt 100 into the skull hole. As discussed above, skull bolts made from ceramic or other hard materials may present an increased risk of failure when driven by the driver tool during insertion into and / or removal from the skull hole, as the two hard materials of the skull bolt and the driver tool tend to concentrate loads on a single point, leading to premature failure due to stress concentrations. An intermediate driver adapter 101 between the skull bolt and the driver tool manufactured using a less hard material such as plastic, fiberglass, etc., can help absorb some of the stress concentrations (e.g., by frictional interference) and improve the failure resistance of the skull device. Additionally and / or alternatively, the driver adapter may be configured to act as a torque limiter by "stripping out" at a lower torque limit compared to the ultimate failure torque of the skull bolt.

[0040] As shown in Figures 5A, 5B and 5C, the distal end 501 of the drive adapter 101 includes an inner surface contour 511 that is a shape complementary to the outer drive geometry of the drive portion 143 of the skull bolt 100 (e.g., complementary to the sinusoidal pattern described above and / or pattern 420 shown in Figure 4C illustrated as 410). Further, the diameter of the inner surface contour 511 is configured such that the drive portion 143 can be inserted into the distal end 501 of the drive adapter 101 and maintained therein by compression fitting or friction. The proximal end 502 of the drive adapter 101 includes an inner surface contour 512 that is a shape complementary to a driver tool. Further, the diameter of the inner surface contour 512 is configured such that the driver tool can be inserted into the proximal end 502 of the drive adapter 101 and maintained therein by compression fitting or friction. In various embodiments, the length of the drive adapter can be about 8 mm to about 12 mm, about 9 mm to about 11 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, etc. The outer diameter of the drive adapter can be about 6 mm to about 10 mm, about 7 mm to about 9 mm, about 8 mm, about 6 mm, about 7 mm, about 9 mm, about 10 mm, etc.

[0041] For example, FIG. 6 illustrates an exemplary driver tool 600 that can be used to attach the cranial access device 10 described above to the skull of a subject. With reference to FIG. 6, the driver tool 600 includes a driver head 610 (e.g., ridged) and a shaft 620. The driver head 610 mounts into a driver handle (not shown here) that allows the driver to be rotated to attach a bolt to the skull. Optionally, the shaft may include markings or gradations. As shown, the driver tool 600 includes a ridged portion 630 disposed at a distal end of the shaft 620. The distal end of the shaft is the end away from the head 610. The ridged portion 630 is configured to be inserted into the proximal end 502 of the drive adapter 101. The distal end of the driver tool also includes a drive pin 640 attached to the ridged portion 630. In various embodiments, the drive pin 640 is configured to have a length that is longer than the length of the drive adapter 101 such that the drive pin 640 is at least partially received within the central passage 110 of the bolt 100. The drive pin 640 may engage with the central passage 110 of the bolt 100 to assist in alignment along a desired trajectory.

[0042] The ridged portion 630 of the shaft allows for the installation and removal of the bolt 100 from the subject's skull via the drive adapter 101. Specifically, the driver 600 can be inserted into the drive adapter 101, which has an opening similar in shape to the opening in the driver's ridged portion 630. In doing so, the driver 600 can engage the bolt 100 via the drive adapter 101 and provide torque to drive the bolt into the subject's skull.

[0043] An exemplary process of using the cranial access device 10 in a surgical procedure includes inserting the ridged portion 630 of the shaft of the driver tool 600 into the proximal end 502 of the drive adapter 101 while the distal end 501 of the drive adapter 101 is coupled with the upper drive portion 143 of the bolt 100. The threads 102 of the bolt 100 are aligned with a pre-drilled hole in the skull. Because the threads 102 are self-tapping, the handle of the driver 600 can be used to turn the bolt 100 in a first direction (e.g., clockwise) through the mid-drive adapter 101 to screw the bolt 100 into the pre-drilled hole. Once the bolt 100 has been screwed a sufficient distance into the skull, the driver tool 600 can be removed.

[0044] A medical device (e.g., a probe) may be attached to the bolt directly and / or via a driver, for example, by insertion into the central passage of the bolt (and optionally the shaft of the driver) to further drive the medical device through the bolt and into the skull. Additionally, after the surgical procedure is completed, the bolt may be removed from the skull by reinserting the driver tool and turning the handle of the driver tool, thereby turning the bolt in a second direction opposite the first direction (e.g., counterclockwise).

[0045] In various embodiments, the outer diameter of the second cylindrical portion 142 of the cranial bolt 100, the outer diameter of the drive adapter 101, and the outer diameter of the shaft 620 of the driver tool 600 are approximately the same, whereby the cranial access device 10 with the driver tool 600 forms an assembly with a continuous diameter, thereby allowing the assembly to pass through a stereotactic instrument used to align the trajectory of the bolt. It should be understood that the cranial access devices described above (with or without the driver tool) have configurations that provide seamless integration of surgical instruments that can be used for general surgical purposes or for specific purposes and, optionally, packaged or assembled together (e.g., via backloading) for insertion into a stereotactic device. Such a configuration allows for ease of use by reducing the number of steps that the surgeon must take to assemble the medical access device and the driver tool prior to insertion into the stereotactic instrument for use in a seamless manner in a surgical procedure. The sequential diameters of the bolt and the drive adapter allow the bolt to be inserted into the stereotactic instrument aligned on a trajectory to the target, and therefore allow the stereotactic instrument to be positioned at any suitable distance from the skull. For example, if the bolt is of a larger diameter than the drive adapter, the bolt would need to be held between the skull and the stereotactic instrument to allow the drive adapter to first pass through the stereotactic instrument and then engage with the bolt. This would then require the user to ensure that the distal portion of the stereotactic instrument is positioned far enough away from the skull to accommodate the length of the bolt, thereby complicating the setup. Thus, the present disclosure provides an instrument and corresponding method that provides a suitable platform for the introduction of surgical, therapeutic, or diagnostic interventions into the central nervous system (CNS), and particularly into the brain of a mammalian subject. The instrument provides stereotactic guidance for the placement and fixation of instruments for use in neurosurgical procedures, and particularly in neurosurgical procedures performed in conjunction with pre- or peri-operative monitoring, such as magnetic resonance imaging (MRI) or computed tomography (CT).Additionally, the devices of the present disclosure are made from materials that are compatible with MRI or CT imaging systems.

[0046] In addition to being compatible with a variety of imaging systems, the skull bolt material is selected to reduce or eliminate artifacts during imaging. For example, Figure 7A illustrates artifacts in an image when a metal skull bolt is used compared to an image using a cranial access device of the present disclosure (Figure 7B), which does not include and / or substantially reduces or eliminates such artifacts.

[0047] According to an embodiment, the cranial access device 10 (including the bolt 100 and the drive adapter 101) has a slim profile, thereby allowing multiple bolts to be inserted into the skull in multiple trajectories within close proximity of each other. The skull-mounted bolts are robust and precise, providing a seamless method for providing stereotactic guidance, placement and fixation for instrument or device manipulation. Additionally, the bolts are MRI compatible, do not produce substantial artifacts during imaging, and have a slim fit that allows for multiple trajectories.

[0048] According to one embodiment, the dimensions of the cranial access device 10 allow the device to be located in close proximity to one or more similar devices. This characteristic provides an advantageous ability to use multiple instruments in contiguous / discontiguous areas in a single treatment session. Thus, the ability of the healthcare provider to apply therapeutic intervention to a larger area of ​​the CNS (e.g., the brain) in a single session is maximized. For example, a single treatment session may include 2-10 skull-mounted bolts (preferably 2-5 bolts) positioned within close proximity of each other. To the extent multiple bolts are used, inter-bolt separation is required, for example, to accommodate a probe driver or probe adapter that may be positioned over the connector portion of the bolt. Furthermore, providing sufficient space between the bolts provides the surgeon with easy access to the individual bolts as well as the area of ​​the skull around the bolts.

[0049] According to an embodiment, the skull-mounted bolts (and cranial access devices) described above are MRI compatible. Two or more bolts can be used in a single treatment session performed within an imaging instrument. Thus, a further aspect of the present disclosure provides a method of treating a biological subject, such as a human or other mammalian subject, using a magnetic field in a magnetic resonance volume.

[0050] According to one embodiment, the magnet can be positioned relative to the subject such that the magnetic resonance volume at least partially encompasses a region of the subject to be treated. A movable applicator adapted to apply energy within an energy application zone is positioned relative to the subject such that the energy application zone intersects the magnetic resonance volume within an area of ​​treatment required by the subject. While the static magnetic field magnet is applying the static magnetic field magnet in the magnetic resonance volume, a radio frequency signal is applied to elicit magnetic resonance signals from tissue of the subject in the magnetic resonance volume. The method also includes receiving these magnetic resonance signals and deriving magnetic resonance information about the tissue of the subject in the magnetic resonance volume from the magnetic resonance signals.

[0051] According to one embodiment, the skull mount bolt or cranial access device described above can be used in conjunction with a robotic probe driver. The robotic probe driver can align and position the tip of the probe through the cranial access device at a certain distance from the target area (e.g., target tissue in the brain) to be treated. The probe can be used to treat various brain diseases by using thermal ablation. The diseases can range from tumors to epilepsy. According to an embodiment, the probe is aligned with the target tissue and inserted into the brain until the tip reaches the target tissue. Laser energy is then transmitted through the probe and emitted from the tip inside the target area. The energy heats the tissue and causes cell death. It should be understood that the temperature of the probe tip can be controlled using cooling gas and thermal monitoring.

[0052] According to an embodiment, the skull mount bolt or cranial access device described above can be used in conjunction with a brain biopsy tool that can be positioned and deployed in the target brain region via the cranial access device.

[0053] According to an embodiment, the skull mount bolt or cranial access device described above can be used in conjunction with a tool for placement of electrodes in the brain (e.g., stereoelectroencephalography (SEEG)). Electrodes can be introduced and placed in a target area (e.g., target tissue within the brain) via the cranial access device.

[0054] According to one embodiment, various drugs can be introduced into the CNS of a subject, and in particular into the brain of a subject, using the apparatus and methods of the present disclosure. A variety of drugs and compositions comprising such drugs can be delivered using the device, including, but not limited to, chemotherapeutic agents, drugs for the treatment of neurodegenerative diseases (e.g., neurotrophic factors or neuroprotective agents), anti-epileptic drugs, anti-depressants, anti-psychotic drugs, anti-inflammatory agents, anti-fibrotic agents, anti-anxiety drugs, and the like.

[0055] According to one embodiment, the agents delivered using the disclosed methods and devices include gene therapy by delivery of transgenes encoding specific factors into the brain, which are highly promising for treating neurodegenerative conditions such as Alzheimer's, Parkinson's, and Huntington's diseases. Similarly, cell-based therapies usually require proper placement of cell populations into targeted regions of the CNS. Delivery of these agents requires that a dose of healing composition is consistently provided at the appropriate location in the brain to ensure that a predictable amount of the intended cells or encoded factors is delivered only to the targeted regions of the brain. Such proper delivery requires that a delivery vector and cells encoding the transgene are implanted at a predetermined site in the targeted brain region. The disclosed instruments and delivery systems allow for proper and localized introduction of such agents into targeted regions of the brain while minimizing surgical intervention. Therefore, improved healing effects can be obtained by enhancing proper placement of transgene-containing donor cell grafts and viral vectors into the brain using the instruments and methods described herein.

[0056] Additionally, drug delivery can be provided as a single dosage form, a bolus or encapsulated dosage form that releases drug over time, and / or the implantation of a delivery device (e.g., an osmotic pump or catheter). Such devices for delivery of healing agents can be used in conjunction with the skull-mounted bolts described herein.

[0057] As previously mentioned, the skull mount bolts are robust and precise, providing a seamless method of providing stereotactic guidance, placement and fixation for the manipulation of an instrument or device. In addition, the skull mount bolts described herein have a slim profile, which allows multiple bolts to be inserted into the skull within close proximity of each other.

[0058] It will be understood that terms such as "same", "equal", "planar" or "coplanar" as used herein when referring to an orientation, layout, position, shape, size, quantity or other measurement do not necessarily mean the exact same orientation, layout, position, shape, size, quantity or other measurement, but are intended to encompass nearly the same orientation, layout, position, shape, size, quantity or other measurement. The term "substantially" may be used to emphasize this meaning unless the context or other description clearly indicates otherwise. For example, terms described as "substantially identical", "substantially equal", or "substantially planar" may be exactly the same, equal or planar, or may be the same, equal or planar within acceptable variations that may occur, for example, due to manufacturing processes and / or tolerances. The term "substantially" may be used to encompass this meaning, particularly when such variations do not substantially alter functionality.

[0059] It will be understood that various modifications may be made to the embodiments disclosed herein. Similarly, the methods disclosed above may be performed according to alternative sequences. Therefore, the above description should not be construed as limiting, but merely as illustrative of various embodiments. Those skilled in the art will recognize that other modifications within the scope and spirit of the claims appended hereto will be possible.

Claims

1. 1. A cranial access device, comprising: A skull bolt, the skull bolt comprising: a distal screw portion; a proximal drive portion including a plurality of protrusions defining an external drive geometry; a central passageway configured to receive a plurality of neurosurgical tools; a skull bolt; Drive adapter and Equipped with The drive adapter includes: a distal end configured to receive and interact with the external drive geometry of the proximal drive portion; a proximal end configured to receive a driver tool; Equipped with Cranial access devices.

2. 10. The cranial access device of claim 1, wherein the skull bolt is manufactured using a non-conductive, rigid material that substantially reduces the formation of artifacts during a magnetic resonance imaging examination.

3. The cranial access device of claim 2 , wherein the non-conductive, rigid material is a ceramic.

4. The cranial access device of claim 1 , wherein the drive adapter is manufactured using a semi-rigid material.

5. The cranial access device of claim 1 , wherein the distal threaded portion is configured for self-tapping of the skull bolt into a skull hole.

6. The cranial access device of claim 5 , wherein the distal threaded portion includes a distal end that does not include threads.

7. The cranial access device of claim 1 , further comprising at least one reducing tube for modifying a diameter of the central passageway.

8. The cranial access device of claim 1 , wherein the central passage is further configured to receive at least a portion of a drive pin of the driver tool.

9. The cranial access device of claim 1 , wherein a first outer diameter of a portion of the skull bolt between the proximal portion and the distal threaded portion is substantially equal to an outer diameter of the drive adapter.

10. The cranial access device of claim 9 , wherein a second outer diameter of a second portion of the skull bolt between the proximal portion and the distal threaded portion is smaller than the first outer diameter.

11. The cranial access device of claim 1 , wherein the torque tolerance of the drive adapter is less than the torque tolerance of the skull bolt.

12. A kit for use in neurosurgery, said kit comprising: Driver tools and Cranial access devices and Equipped with The cranial access device comprises: A skull bolt, the skull bolt comprising: a distal screw portion; a proximal drive portion including a plurality of protrusions defining an external drive geometry; a central passage configured to receive a neurosurgical tool; a skull bolt; Drive adapter and Equipped with The drive adapter includes: a distal end configured to receive and interact with the external drive geometry of the proximal drive portion; a proximal end configured to receive the driver tool; Equipped with The driver tool is inserted into the cranial access device, the cranial access device providing a continuous lumen for insertion into a stereotactic device during a surgical procedure. kit.

13. 13. The kit of claim 12, wherein the skull bolt is manufactured using a non-conductive, rigid material that substantially reduces the formation of artifacts during a magnetic resonance imaging examination.

14. The kit of claim 13 , wherein the non-conductive, rigid material is a ceramic.

15. The kit of claim 12 , wherein the drive adapter is manufactured using a semi-rigid material.

16. The kit of claim 12 , wherein the distal threaded portion is configured for self-tapping of the skull bolt into a skull hole.

17. The kit of claim 16 , wherein the distal threaded portion includes a non-threaded distal end.

18. 13. The kit of claim 12, further comprising at least one reducing tube for modifying a diameter of the central passageway.

19. The kit of claim 12 , wherein the central passage is further configured to receive at least a portion of a drive pin of the driver tool.

20. The kit of claim 12 , wherein a first outer diameter of a portion of the skull bolt between the proximal portion and the distal threaded portion is substantially equal to an outer diameter of the drive adapter.

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