Guide for a stimulation electrode

Abstract

A robotic guide system for a medical device. The robotic guide system includes a first steering assembly including a first segment of bidirectional asymmetric notches, a first tendon structured to actuate the first steering assembly in a first direction within a first plane, and a second tendon structured to actuate the first steering assembly in a second direction within the first plane; a second steering assembly including a second segment of bidirectional asymmetric notches, a third tendon structured to actuate the second steering assembly in a third direction within a second plane, and a fourth tendon structured to actuate the second steering assembly in a fourth direction within the second plane; and a latching device structured to selectively engage and release the medical device.

Description

Attorney Docket No.11258-014WO1 P.C.T. PATENT APPLICATION for GUIDE FOR A STIMULATION ELECTRODE Inventors: YASH CHITALIA AJMAL ZEMMAR BEHNAM MORADKHANI HARSHITH JELLAAttorney Docket No.11258-014WO1 GUIDE FOR A STIMULATION ELECTRODE CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No.63 / 596,056, filed on November 3, 2023, the entire contents of which are incorporated herein by reference. BACKGROUND

[0002] This disclosure relates to steering devices for medical leads, guidewires, and / or lumens. More specifically, the disclosure relates to robotic steering devices for medical catheters.

[0003] Manual navigation of spinal cord stimulation (SCS) electrodes is very complicated, especially when the intended target is in a dorsal root ganglion. Medically refractory pain is a major problem in the United States. SCS is a well-established surgical alternative for refractory pain that also reduces opioid usage in patients, with over 60% reporting a reduction in opioid use. Yet, SCS is associated with high rates of complications. Particularly in the suppression of complex regional pain, stimulation of the dorsal root ganglia (DRGS) has demonstrated a higher rate of success over SCS, but also comes with increased operative risks. For SCS and DRGS to be successful, an electrode lead must be manually placed at a very specific location along the spinal cord. However, manual placement of SCS / DRGS electrodes is extremely challenging, particularly in the presence of scar tissue. The challenges of electrode placement lead to a higher likelihood of electrode migration and procedural complications like dural puncture, trauma to the cord, hematoma, etc. which are the leading contributor to the risks associated with SCS / DRGS. SUMMARY

[0004] One implementation relates to a robotic guide system for a medical device. The robotic guide system includes a first steering assembly including a first segment of bidirectional asymmetric notches, a first tendon structured to actuate the first steering assembly in a first direction within a first plane, and a second tendon structured to actuate the first steering assembly in a second direction within the first plane; a second steering assembly including a second segment of bidirectional asymmetric notches, a third tendon structured to actuate the second steering assembly in a third direction within a second plane, and a fourth tendon structured to actuate the second steering assembly in a fourth direction within the second plane; and a latching device structured to selectively engage and release the medical device.Attorney Docket No.11258-014WO1

[0005] Another implementation relates to a robotic guide system for a medical device. The robotic guide system includes a first steering assembly including a first segment of bidirectional asymmetric notches, a first tendon structured to actuate the first steering assembly in a first direction within a first plane, and a second tendon structured to actuate the first steering assembly in a second direction within the first plane; a second steering assembly including a second segment of bidirectional asymmetric notches, a third tendon structured to actuate the second steering assembly in a third direction within a second plane, and a fourth tendon structured to actuate the second steering assembly in a fourth direction within the second plane; a locking system including a plurality of magnets positioned along an axial length of the robotic guide system; and a locking actuator configured to interact with the magnets of the locking system.

[0006] This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements. BRIEF DESCRIPTION OF DRAWINGS

[0007] The device is explained in even greater detail in the following drawings. The drawings are merely exemplary and certain features may be used singularly or in combination with other features. The drawings are not necessarily drawn to scale.

[0008] FIG.1 is a schematic view of a guide system, according to some implementations.

[0009] FIG.2 is a front view of a bidirectional asymmetric notch (BAN) segment, according to some implementations.

[0010] FIG. 3 is a finite element analysis of the BAN segment of FIG. 2 in a flexed position, according to some implementations.

[0011] FIG. 4 is a perspective view of a latching mechanism of the guide system of FIG. 1, according to some implementations.

[0012] FIG. 5 is a photograph of the guide system of FIG. 1 navigating a phantom spine, according to some implementations.Attorney Docket No.11258-014WO1

[0013] FIG. 6 is a photograph of a magnetic lock of the guide system of FIG. 1, according to some implementations.

[0014] FIG.7 is another photograph of a magnetic lock of the guide system of FIG.1, according to some implementations.

[0015] FIG.8 is a photograph of a tendon actuator of the guide system of FIG.1, according to some implementations.

[0016] FIG.9 is a photograph of the guide system of FIG.1, according to some implementations.

[0017] FIG.10 is a compound view of another guide system, according to some implementations.

[0018] FIG. 11 is a perspective view of the guide system of FIG. 10, according to some implementations.

[0019] FIG.12 is a front view of an alternative compound tube for the guide system of FIG.10, according to some implementations.

[0020] FIG. 13 is a perspective view of a link of the alternative compound tube of FIG. 12, according to some implementations.

[0021] FIG.14 is a front view of an alternative compound tube for the guide system of FIG.10, according to some implementations.

[0022] FIG.15 is a schematic representation of the guide system of FIG.10 bending in a dorsal direction, according to some implementations.

[0023] FIG.16 is a schematic representation of the guide system of FIG.10 bending in a lateral direction, according to some implementations.

[0024] FIG.17 is a compound view of a backend of the guide system of FIG.10 including: FIG. 17A showing an isolated latching mechanism setup, representation of jaw guide angles, and initial compression; FIG. 17B and FIG. 17F showing graphical representations of latching mechanism data; and FIGS.17C-E showing force plots of each jaw guide (3.3◦, 5.5◦, and 7.7◦, respectively) when latching mechanism is engaged versus disengaged, according to some implementations.Attorney Docket No.11258-014WO1

[0025] FIG.18 is a compound view of an experimental setup and results of the guide system of FIG. 10 including: FIG. 18A showing an experimental setup used for conducting free space experimental trials; FIGS. 18B and C comparing experimental data with kinematic model predictions for dorsal bending (FIG.18B) when magnetic locking is absent and (FIG.18C) when it is present; FIGS.18D and E comparing experimental data with kinematic model predictions for (FIG. 18D) dorsal bending when magnetic locking is absent and (FIG. 18E) when it is present; and FIG. 18F comparing robot active oscillation in absence and presence of magnetic locking, according to some implementations.

[0026] FIG.19 is a perspective view of a trial setup of the guide system of FIG.10 including a phantom spine, according to some implementations.

[0027] FIGS.20 and 21 a perspective views of the guide system of FIG.10 in the phantom spine of FIG.19, according to some implementations.

[0028] FIG.22 is a compound view of another guide system, according to some implementations.

[0029] FIG.23A is a schematic diagram of the guide system of FIG.22 showing the guide system actuated by pulling the actuation tendon bends in a helical shape and determines an imaginary cylinder with specific dimensions, according to some implementations.

[0030] FIG.23B is a schematic representation of the guide system shown in FIG.23A including coordinate frames defined at the tip of the outer tube and on bottom circle of the imaginary cylinder, according to some implementations. DETAILED DESCRIPTION

[0031] Following below are more detailed descriptions of concepts related to, and implementations of, methods, apparatuses, and systems for guiding medical leads, guidewires. Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0032] Referring to the figures generally, the various embodiments disclosed herein relate to systems, apparatuses, and methods for a robotic guide system that attaches to a passive electrodeAttorney Docket No.11258-014WO1 lead (e.g., a lead used in spinal cord stimulation) thereby making the leads remotely steerable. The robotic guide system attaches to the lead by covering or enveloping the lead, or by sitting next to the lead and latching on to it. The robotic guide system can steer electrodes or other leads within a epidural cavity of a patient for the treatment of refractory pain or for SCI rehabilitation. In some implementations, the robotic guide system includes a continuum robotic catheter, with an outer diameter of 0.94 mm and a length of approximately 200 mm, with an active distal end and a semi- active proximal body. The size of the device is deliberately micro-scale, such that both the steering robot and the electrode lead will fit within the epidural cavity. The body has latches along its length, where electrode leads from a variety of manufacturers can be attached, making the device manufacturer agnostic. Even paddle leads can be attached to the current manifestation of the device. A single tendon-actuated mechanism controls all the latches, allowing the device to be remotely detached from the electrode once placement is completed. The distal tip of the device includes two non-magnetic tendon-actuated joints micro-machined within its structure, allowing a clinician to control the tip. The two joints offer a three-dimensional workspace to the clinicians, allowing them to steer the tip in any direction. The proximal body of the device includes a set of neodymium magnets along its length, allowing the proximal body to be locked in position while the distal tip is steered safely. To lock the proximal body of the device, a larger locking neodymium magnet (e.g., a N504-inch diameter magnet) will be located outside patient’s body, controlled by a serial manipulator (e.g., a robotic arm). The magnetic locking feature inhibits movement of the proximal body while the head is steered safely around the spinal cord to the ventral side or to a specific dorsal root ganglion, for example. The tendon-driven and magnetic steering technique provides advantageous manipulation of flexible and long robotic catheters. Locking is achieved magnetically in some implementations, but can be made non-magnetic. Importantly, distal tip steerability of SCS electrodes allows the electrode to be readjusted if it migrates post-operatively.

[0033] Spinal cord stimulation (SCS) is a surgical treatment that can reduce opioid usage in patients, with 17% of users completely stopping opioids within a year of stimulation (and over 60% reporting a reduction in opioid use). Stimulation is performed with wire or paddle electrodes placed on the dorsal column of the spinal cord, which is associated with sensory and ascending pathways. The current standard-of-care involves manual placement of SCS electrodes, which is technically challenging, particularly in the presence of tortuous anatomical constraints arising from scar tissue or spine disease. For more selective delivery of pain therapy, a significant target is the dorsal root ganglion (DRG) located at the end of afferent sensory axons in the anterolateralAttorney Docket No.11258-014WO1 epidural space. The DRG plays a key role in relaying sensory information from the peripheral nerves to the central nervous system. Therefore, stimulation of the DRG (DRGS) results in more selective treatment of pain. While specific DRG stimulators have been developed for surgical treatment of pain (e.g., targeting the dorsal pain fibers of the DRG), currently, surgeons can only steer the device to its target by hand, which is extremely challenging and has a steep learning curve. Therefore, DRG stimulation is widely accepted as being even more technically difficult compared to SCS stimulation, associated with higher intra-operative pain. Electrode migration is the leading cause of SCS complications followed by procedural complications such as accidental dural puncture, blunt trauma to the spinal cord, epidural hematoma. In case of electrode migration, the electrode may need to be removed and replaced through a laminectomy, leading to additional risk to the patient. This could be avoided by repositioning of electrode leads achieved via the robotic guide system described herein. Similarly, procedural complications like dural puncture or trauma to the cord can be inhibited via navigation of the distal tip of the electrode to avoid the dura. For pain specific to the back, legs, and other extremities, DRGS has emerged as a potential target for neurostimulation and has been regularly used for the treatment of complex regional pain syndrome of the foot, knees, upper limbs, among other cases where pain was limited to a certain part of the body. However, most studies note the significantly higher technical challenges associated with manual electrode placement at DRGs in comparison to standard SCS wire / paddle electrodes, with higher intraoperative pain and risks of complications. Nearly half (47%) of DRGS associated complications are associated with the device placement (e.g., migration and lead damage), while a quarter of the complications arise from procedural difficulties (e.g., accidentally puncturing the dura, hematoma, among others). The predominant hypothesis is that these complications arise from the difficulty to reach the DRG due to the sharp curvature and the challenges of selectively reaching the dorsal portion of the DRG (i.e., pain fibers). The robotic guide system disclosed herein allows steering capabilities to position SCS leads to selective target nerve roots and DRG locations.

[0034] The robotic guide system improves SCS / DRGS electrode placement outcomes by allowing clinicians to precisely steer the tips of SCS electrodes. For medically refractory chronic pain, SCS and DRGS are currently used as a last recourse, due to challenges associated with manual electrode navigation and placement. The robotic guide system provides the foundation of a technology that can precisely steer electrodes to a deep-seated target location, thereby reducing challenges. Furthermore, remote steering can reduce radiation exposure for the surgeons.Attorney Docket No.11258-014WO1 Therefore, the robotic guide system provides a step towards efficient surgical management of medically refractory pain and reducing the overdependence and misuse of prescription drugs for pain management.

[0035] In some implementations, robotic guide system discussed below possess five primary properties: 1) a micro-scale diameter to fit within the epidural space, 2) two degrees-of-freedom to navigate in any direction (i.e., a 3D-workspace), 3) a length that allows the distal-tip to reach DRGs (e.g., 200 mm), 4) a capability to lock a proximal shape to inhibit accidentally puncturing the dura, and 5) a capability to deploy a lead to a target location.

[0036] As shown in FIG. 1, a robotic guide system 20 includes a catheter 24 sized to house a steering device 28 and a medical device 32 (e.g., a spinal cord stimulation (SCS) lead, a guidewire, etc.). In some implementations, the catheter 24 defines an outer diameter of 0.94 mm and a length of 200 mm. In some implementations, the outer diameter is sized to be deliberately micro-scale and fit within the epidural cavity of a patient’s spine. Additionally, the length of the catheter 24 may be adjusted for specific operations or uses.

[0037] The steering device 28 includes a steering tip 36 shaped to inhibit punctures of a dural lining, a first steering assembly 40 that articulates in a first plane (e.g., up and down in FIG.1), a second steering assembly 44 that articulates in a second plane (e.g., into and out of the page in FIG. 1), a latching device 48 that selectively engages and releases the medical device 32, and a locking system 52 that cooperates with a locking actuator 56 to selectively lock portions of the steering device 28 in position during use. In some implementations, the steering device 28 also includes a housing or steering lumen 60 that houses the latching device 48 and the locking system 52. In some implementations, the housing or steering lumen 60 encapsulates the steering tip 36, the first steering assembly 40, and the second steering assembly 44 as well. In some implementations, the housing or steering lumen 60 is constructed using silicone tubing.

[0038] The first steering assembly 40 includes a micromachined segment of bidirectional asymmetric notch (BAN) joints 64 that provide articulation of the first steering assembly 40 in a single plane (i.e., a single degree of freedom). The first steering assembly 40 shown in FIG. 1 includes six BAN joints 64. In some implementations, more than six or less than six BAN joints 64 are included in the first steering assembly 40.Attorney Docket No.11258-014WO1

[0039] The first steering assembly 40 also includes a first tendon actuation system 68 including a first tendon 72 fastened (e.g., adhered, threaded to, welded to, etc.) to or fastened adjacent to a distal BAN joint 76 and extending out of the catheter 24. The first tendon 72 can be manipulated to actuate the first steering assembly 40 in a first direction. A second tendon 80 is fastened (e.g., adhered, threaded to, welded to, etc.) to or fastened adjacent to the distal BAN joint 76 and extends out of the catheter 24. The second tendon 80 can be manipulated to actuate the first steering assembly 40 in a second direction that is opposite of the first direction. In some implementations, the first tendon 72 and the second tendon 80 are structured to actuate the first steering assembly 40 under tension. That is to say, pulling on the first tendon 72 results in movement of the first steering assembly 40 in the first direction, and pulling on the second tendon 80 results in movement of the first steering assembly 40 in the second direction.

[0040] A first tendon actuation housing 84 supports a first motor 88 that operates to move a first load cell 92 along a first linear guide 96. The first tendon 72 is connected to the first load cell 92 such that operation of the first motor 88 controls a tension of the first tendon 72 and therefore the actuation of the first steering assembly 40 in the first direction. A first pulley 100 can be included to guide the first tendon 72 between the catheter 24 and the first load cell 92. In some implementations, the first motor 88 and the first linear guide 96 are a ball screw actuator, a linear actuator, a servo motor and linear guide, a gear drive, or another actuation system. The first load cell 92 transmits first loading information indicative of the tension applied to the first tendon 72.

[0041] The first tendon actuation housing 84 also supports a second motor 104 that operates to move a second load cell 108 along a second linear guide 112. The second tendon 80 is connected to the second load cell 108 such that operation of the second motor 104 controls a tension of the second tendon 80 and therefore the actuation of the first steering assembly 40 in the second direction. A second pulley 116 can be included to guide the second tendon 80 between the catheter 24 and the second load cell 108. In some implementations, the second motor 104 and the second linear guide 112 are a ball screw actuator, a linear actuator, a servo motor and linear guide, a gear drive, or another actuation system. The second load cell 108 transmits second loading information indicative of the tension applied to the second tendon 80.

[0042] The second steering assembly 44 includes a micromachined segment of bidirectional asymmetric notch (BAN) joints 120 that provide articulation of the second steering assembly 44 in a single plane (i.e., a single degree of freedom). The second steering assembly 44 shown inAttorney Docket No.11258-014WO1 FIG.1 includes thirty-eight BAN joints 120. In some implementations, more than thirty-eight or less than thirty-eight BAN joints 120 are included in the second steering assembly 44. In some implementations the plane of actuation of the second steering assembly 44 is normal to the plane of actuation of the first steering assembly 40.

[0043] The second steering assembly 44 also includes a second tendon actuation system 124 including a third tendon 128 fastened (e.g., adhered, threaded to, welded to, etc.) to or fastened adjacent to a distal BAN joint 132 and extending out of the catheter 24. The third tendon 128 can be manipulated to actuate the second steering assembly 44 in a third direction different from the first direction and the second direction. A fourth tendon 136 is fastened (e.g., adhered, threaded to, welded to, etc.) to or fastened adjacent to the distal BAN joint 132 and extends out of the catheter 24. The fourth tendon 136 can be manipulated to actuate the second steering assembly 44 in a fourth direction that is opposite of the third direction. In some implementations, the third tendon 128 and the fourth tendon 136 are structured to actuate the second steering assembly 44 under tension. In other words, pulling on the third tendon 128 results in movement of the second steering assembly 44 in the third direction, and pulling on the fourth tendon 136 results in movement of the second steering assembly 44 in the fourth direction.

[0044] A second tendon actuation housing 140 supports a third motor 144 that operates to move a third load cell 148 along a third linear guide 152. The third tendon 128 is connected to the third load cell 148 such that operation of the second steering assembly 44 controls a tension of the third tendon 128 and therefore the actuation of the second steering assembly 44 in the third direction. A third pulley 156 can be included to guide the third tendon 128 between the catheter 24 and the third load cell 148. In some implementations, the third motor 144 and the third linear guide 152 are a ball screw actuator, a linear actuator, a servo motor and linear guide, a gear drive, or another actuation system. The third load cell 148 transmits third loading information indicative of the tension applied to the third tendon 128.

[0045] The second tendon actuation housing 140 also supports a fourth motor 160 that operates to move a fourth load cell 164 along a fourth linear guide 168. The fourth tendon 136 is connected to the fourth load cell 164 such that operation of the fourth motor 160 controls a tension of the fourth tendon 136 and therefore the actuation of the second steering assembly 44 in the fourth direction. A fourth pulley 172 can be included to guide the fourth tendon 136 between the catheter 24 and the fourth load cell 164. In some implementations, the fourth motor 160 and the fourthAttorney Docket No.11258-014WO1 linear guide 168 are a ball screw actuator, a linear actuator, a servo motor and linear guide, a gear drive, or another actuation system. The fourth load cell 164 transmits fourth loading information indicative of the tension applied to the fourth tendon 136.

[0046] The latching device 48 (see also FIG.4) includes fingers 176 that are movable between a closed position engaging the medical device 32 and an open position disengaging or releasing the medical device 32. The fingers 176 are biased toward the open position by torsional springs 180 positioned within a latch housing 184. In some implementations, the fingers 176 are manufactured with a 10 μm resolution microArch 3D-printer (Boston Micro Fabrication) of a bio-compatible resin. A latch actuation system 188 includes a latching tendon 192 that is connected to the torsional springs 180 so that actuation or movement of the latching tendon 192 in tension overcomes the bias of the torsional springs 180 and moves the fingers 176 to the closed position to engage the medical device 32. In some implementations, the torsional springs 180 and the latching tendon 192 tendon are micro-machined from a sheet of nitinol of thickness 0.4 mm (WS-Flex laser by Optec Laser Systems Inc.). In some implementations, the torsional springs 180 bias the fingers toward the closed position and tension of the latching tendon 192 moves the fingers 176 toward the open position. The latch actuation system 188 includes a latch controller housing 196 that supports a latch motor 200 that operates to move a latch load cell 204 along a latch linear guide 208. The latching tendon 192 is connected to the latch load cell 204 such that operation of the latch motor 200 controls a tension of the latching tendon 192 and therefore the actuation of the latching device 48 between the open position and the closed position. A latch pulley 212 can be included to guide the latching tendon 192 between the catheter 24 and the latch load cell 204. In some implementations, the latch motor 200 and the latch linear guide 208 are a ball screw actuator, a linear actuator, a servo motor and linear guide, a gear drive, or another actuation system. The latch load cell 204 transmits latch loading information indicative of the tension applied to the latching tendon 192.

[0047] The locking system 52 includes a series of magnets 216 positioned within the housing or steering lumen 60. In some implementations, the magnets 216 are radial magnets positioned around the first tendon actuation system 68, the second tendon actuation system 124, and the latch actuation system 188. The magnets 216 are fixed in position axially along the housing or steering lumen 60. The locking actuator 56 includes an external magnet system that can be manipulated and positioned in a desired position and activated or actuated to lock the series of magnets 216 inAttorney Docket No.11258-014WO1 place during use. In some implementations, the locking actuator 56 includes a very powerful rare earth magnet (e.g., a neodymium magnet) mounted on a robotic arm that can be positioned during surgery. The locking actuator 56 can be actuated to lock the locking system 52 in place during surgery to that the first steering assembly 40 and second steering assembly 44 can be manipulated to guide the steering tip 36 to a target location without movement of the proximal portions of the catheter 24. In some implementations, the magnets 216 include two radially polarized N52- neodymium magnetic rings located approximately 10 mm from each other. The polarity of these magnet rings along the housing or steering lumen 60 allows for the magnets 216 along the housing or steering lumen 60 to be locked using the locking actuator 56.

[0048] A controller 220 includes a processing circuit having a processor and a memory device, a control system having a first steering circuit, a second steering circuit, and a latching circuit, and a user interface. Generally, the controller 220 is structured to receive the first loading information from the first load cell 92, the second loading information from the second load cell 108, the third loading information from the third load cell 148, the fourth loading information from the fourth load cell 164, and the latching loading information from the latch load cell 204 and to control operation of the first motor 88, the second motor 104, the third motor 144, the fourth motor 160, and the latching motor 200 based on the received information and user commands received via the user interface.

[0049] In one configuration, the circuits of the control system are embodied as machine or computer-readable media that is executable by the processor. As described herein and amongst other uses, the machine-readable media facilitates performance of certain operations to enable reception and transmission of data. For example, the machine-readable media may provide an instruction (e.g., command, etc.) to, e.g., acquire data. In this regard, the machine-readable media may include programmable logic that defines the frequency of acquisition of the data (or, transmission of the data). The computer readable media may include code, which may be written in any programming language including, but not limited to, Java or the like and any conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program code may be executed on one processor or multiple remote processors. In the latter scenario, the remote processors may be connected to each other through any type of network (e.g., CAN bus, etc.).Attorney Docket No.11258-014WO1

[0050] In another configuration, the circuits of the control system are embodied as hardware units, such as electronic control units. As such, the circuits of the control system may be embodied as one or more circuitry components including, but not limited to, processing circuitry, network interfaces, peripheral devices, input devices, output devices, sensors, etc. In some embodiments, the circuits of the control system may take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (IC), discrete circuits, system on a chip (SOCs) circuits, microcontrollers, etc.), telecommunication circuits, hybrid circuits, and any other type of “circuit.” In this regard, the circuits of the control system may include any type of component for accomplishing or facilitating achievement of the operations described herein. For example, a circuit as described herein may include one or more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, and so on). The circuits of the control system may also include programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like. The circuits of the control system may include one or more memory devices for storing instructions that are executable by the processor(s) of the circuits of the control system. The one or more memory devices and processor(s) may have the same definition as provided below with respect to the memory device and the processor. In some hardware unit configurations, the circuits of the control system may be geographically dispersed throughout separate locations in the power system. Alternatively and as shown, the circuits of the control system may be embodied in or within a single unit / housing, which is shown as the controller 220.

[0051] In the example shown, the controller 220 includes the processing circuit having the processor and the memory device. The processing circuit may be structured or configured to execute or implement the instructions, commands, and / or control processes described herein with respect to the circuits of the control system. The depicted configuration represents the circuits of the control system as machine or computer-readable media. However, as mentioned above, this illustration is not meant to be limiting as the present disclosure contemplates other embodiments where the circuits of the control system, or at least one circuit of the circuits of the control system, is configured as a hardware unit. All such combinations and variations are intended to fall within the scope of the present disclosure.Attorney Docket No.11258-014WO1

[0052] The hardware and data processing components used to implement the various processes, operations, illustrative logics, logical blocks, modules and circuits described in connection with the embodiments disclosed herein (e.g., the processor) may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, the one or more processors may be shared by multiple circuits (e.g., the circuits of the control system may comprise or otherwise share the same processor which, in some example embodiments, may execute instructions stored, or otherwise accessed, via different areas of memory). Alternatively or additionally, the one or more processors may be structured to perform or otherwise execute certain operations independent of one or more co-processors. In other example embodiments, two or more processors may be coupled via a bus to enable independent, parallel, pipelined, or multi- threaded instruction execution. All such variations are intended to fall within the scope of the present disclosure.

[0053] The memory device (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and / or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. The memory device may be communicably connected to the processor to provide computer code or instructions to the processor for executing at least some of the processes described herein. Moreover, the memory device may be or include tangible, non-transient volatile memory or non-volatile memory. Accordingly, the memory device may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein.

[0054] The first steering circuit is structured to receive loading information from the first load cell 92 and the second load cell 108, and user input (e.g., from a joystick) and to actuate the firstAttorney Docket No.11258-014WO1 motor 88 and the second motor 104 of the first tendon actuation system 68 to provide movement of the first steering assembly 40 in the first direction or the second direction, as desired by the user.

[0055] The second steering circuit is structured to receive loading information from the third load cell 148 and the fourth load cell 164, and user input (e.g., from the joystick) and to actuate the third motor 144 and the fourth motor 160 of the second tendon actuation system 124 to provide movement of the second steering assembly 44 in the third direction and the fourth direction, as desired by the user.

[0056] The latching circuit is structured to receive loading information from the latch load cell 204 and user input (e.g., a latch button) and to actuate the latching motor 200 of the latch actuation system 188 to provide movement of the latching tendon 192 and move the fingers 176 of the latching device 48 between the open position and the closed position.

[0057] While various circuits with particular functionality are described, it should be understood that the controller 220 may include any number of circuits for completing the functions described herein. For example, the activities and functionalities of the circuits of the control system may be combined in multiple circuits or as a single circuit. Additional circuits with additional functionality may also be included. Further, the controller 220 may further control other activity beyond the scope of the present disclosure. In some embodiments, the circuits described herein may include one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to perform the operations performed herein and described with reference to circuits.

[0058] As mentioned above and in one configuration, the “circuits” may be implemented in machine-readable medium for execution by various types of processors. An identified circuit of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions, which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified circuit need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the circuit and achieve the stated purpose for the circuit. Indeed, a circuit of computer readable program code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across severalAttorney Docket No.11258-014WO1 memory devices. Similarly, operational data may be identified and illustrated herein within circuits, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.

[0059] While the term “processor” is briefly defined above, the term “processor” and “processing circuit” are meant to be broadly interpreted. In this regard and as mentioned above, the “processor” may be implemented as one or more general-purpose processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), or other suitable electronic data processing components structured to execute instructions provided by memory. The one or more processors may take the form of a single core processor, multi-core processor (e.g., a dual core processor, triple core processor, quad core processor, etc.), microprocessor, etc. In some embodiments, the one or more processors may be external to the apparatus, for example the one or more processors may be a remote processor (e.g., a cloud based processor). Alternatively or additionally, the one or more processors may be internal and / or local to the apparatus. In this regard, a given circuit or components thereof may be disposed locally (e.g., as part of a local server, a local computing system, etc.) or remotely (e.g., as part of a remote server such as a cloud based server). To that end, a “circuit” as described herein may include components that are distributed across one or more locations.

[0060] Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general-purpose computer, specialAttorney Docket No.11258-014WO1 purpose computer, or special purpose processing machines to perform a certain function or group of functions.

[0061] As shown in FIG. 2, the BAN joints 64 and the BAN joints 120 are designed by micromachining a rectangular pattern in a tube (i.e., hollow lumen) of nickel-titanium (e.g., nitinol) with a femtosecond laser system (e.g., WS-Flex laser by Optec Laser Systems Inc.). The BAN pattern makes the first steering assembly 40 and the second steering assembly 44 compliant in the direction of the notches, providing a one degree-of-freedom joint (1-DoF joint). By micromachining two such BAN joints orthogonal to each other (e.g., the first steering assembly 40 and the second steering assembly 44 in cooperation), a 2-DoF tendon-driven tip with four tendons allows the robotic guide system 20 to cover a 3D-workspace (i.e., front-back and up-down motion). In some implementations, the robotic guide system 20 defines an outer diameter of 0.94 mm and the following BAN joint parameters: a notch depth d of 0.893 mm, a width F1of 0.3 mm, and a separation height h of 0.2 mm between consecutive notches. In some implementations, the BAN joints 64 of the first steering assembly 40 define more flexible joints than the thirty-eight BAN joints 120 making the turning arc of the first steering assembly 40 smaller than the turning arc of the second steering assembly 44. In some implementations the first steering assembly 40 defines an axial length of 2.8 mm. In some implementations, the second steering assembly 44 defines an axial length of 19 mm.

[0062] As discussed above, the medical device 32 can include SCS leads. During testing of the robotic guide system 20 discussed above, the inventors conducted testing with two SCS leads produced by leading electrode manufacturers, Abbott Laboratories and Boston Scientific, using a material characterization tensile testing machine (Instron 5569 Mechanical Tester). The robotic guide system 20 is stiff enough to steer the SCS leads. In other words, the robotic guide system 20 guides the medical device 32 because the stiffness of the robotic guide system 20 is greater than the stiffness of the medical device 32. In typical systems, the medical device 32 is stiffer than a guidewire or other guiding system. The stiffness of the robotic guide system 20 allows the user to dictate and co0ntrol the position and direction of the catheter 24 and the medical device 32 during positioning. The stiffness of the BAN joints 64, 120 can be tuned very precisely by changing two variables: the BAN notch depth (d), and the space between notches (h). Finite element analysis (FEA) can be used to adjust the values for these two parameters (ANSYS Mechanical modeling) to achieve the desired stiffness at each bending joint. Therefore, the bending stiffness of the BANAttorney Docket No.11258-014WO1 joints 64, 120 can be precisely varied over a very high range (from very compliant to extremely stiff), simply by changing the depth and the spacing between notches. This is contrary to other modalities of actuation where changing bending properties typically involves changing the diameter of the robot. By keeping the diameter of the robotic guide system 20 consistent, a wide range of joint stiffnesses is achieved by tuning the machining properties of the BAN joints 64, 120. Since the diameter of the robotic guide system 20 remains unchanged, the tuning will not affect the capability to fit robotic guide system 20 within the epidural space.

[0063] Additionally, the number of notches 64, 120 included in the first steering assembly 40 and the second steering assembly 44 can be determined for the minimum curvature required for the SCS lead steering task. A geometric analysis from a set of anonymized spinal cord CT scan datasets can be used to determine the minimum curvatures that are advantageous for the robotic guide system 20 to take sharp curves laterally to reach DRGs or other target locations.

[0064] In some implementations, the robotic guide system 20 can be human-teleoperated via a remote clinician. For example, a clinician can be located remote from the robotic guide system 20 (e.g., at a different hospital) and control the robotic guide system 20 remotely via the controller 220. The controller 220 houses a mechanical model that accurately predict the behavior of the robot and collaborative control between the tendon actuated and magnetically actuated components that steer the robotic guide system 20.

[0065] As shown in FIGS.5-8, the robotic guide system 20 has been tested navigating through a phantom spine. Guidance systems used in cardiovascular applications can take support from vascular walls while steering. However, steering through epidural cavity poses a risk of dura puncture if the robotic guide system 20 were to lean against the dura surface while steering. Testing of the robotic guide system 20 has demonstrated a magnetic-locking system on a benchtop which allows the medical device 32 to be steered, without the housing or steering lumen 60 or the catheter 24 running into critical anatomy. FIG.8 shows the first tendon actuation housing 84 that can actuate the first tendon 72 and the second tendon 80 while measuring the force to pull either tendon via the load-cells 92, 108. The motors 88, 104 can control tendon-stroke down to a resolution of 10 microns and the load-cells 92, 108 can measure forces of up to 5 lbs., allowing for precise control of the device tip in the epidural space.Attorney Docket No.11258-014WO1

[0066] The mechanical model used by the controller 220 relates the amount of tendon-tension to the bending curvature of the joint. While Cosserat beam bending theory will provide for gold- standard estimates, each newly machined prototype will deviate from theory due to machining imperfections, variable friction losses, etc. and a calibration will be performed for each fabricated prototype to ensure repeatable control.

[0067] As shown in FIG.9, a locking actuator 56 in the form of a 4-inch wide and 1-inch thick N50 neodymium magnet (Radial Magnets Inc.) can be mounted to the end-effector of a Stäubli TX2-606-axis robotic arm. The magnetic field generated for locking the robotic guide system 20 in a specific configuration relates to the position and orientation of the permanent magnet and therefore the end-effector of the arm. These will be modeled, identified, and related to the joint space of the robot. A higher-level controller will ensure that the arm follows the tip keeping the body of the robotic guide system 20 locked when the steering tip 36 is to be steered. When not steering, the arm will move out of the way. EXAMPLE 2

[0068] Below, the inventors provide another exemplary robotic guide system referred to as the ExoNav 300. Extensive testing and design considerations are discussed below relative to the ExoNav and shown in FIGS.10-21. FIG.10 shows the complete design of the robot ExoNav 300. ExoNav 300 comprises two primary components, a frontend 304 and a backend 308. The frontend 304 encompasses the continuum robot section of the design, while the backend 308 houses the actuation stage.

[0069] A. Frontend Design

[0070] The frontend 304 design of the ExoNav 300 is primarily comprised of two components: a 3-D-printed compound tube 312 with links 316 including embedded ring magnets for magnetic locking, and a distal 2-DoF machined nitinol tip 320, which allows for distal steering.

[0071] The 3-D-Printed Compound Tube 312 includes a simple interlocking design with alternating hinges in order to achieve 2-DoFs. The tube has a diameter of 7 mm and each link 316 contributes 14.88 mm to the length of the assembly. In the final assembly, twelve alternating links 316 are used along with two modified links to interface with the backend (including the mechatronics to drive the robot) and the distal tip segment (made of 2-DoF nitinol joints). TheAttorney Docket No.11258-014WO1 structure of a standard link 316 includes pins 324 and sockets 328 to interface with each other. The link 316 interfacing with the backend contains only pins 324 to begin the chain of links 316, while the link 316 interfacing with the nitinol tube 320 only has sockets 328 and also reduces the circumference of the tendon routing to guide tendons into the nitinol tube 320. Each link 316 was printed on a ProJet MJP 2500 and is comprised of two hinge pins 324, two perpendicular sockets 328, nine tendon routing channels around the circumference, and a central 2-mm hole through which the electrode travels.

[0072] The clearance of the tendon routing holes and the electrode hole are 0.25 and 0.17 mm, respectively, primarily to reduce friction with the postprocessed 3-D-printed parts. Four of the nine tendons are used for assembly. They are spaced 90◦ apart and run through the hinges to constrain their movement to one axis. The remaining tendons are used to control the movement of the robot or to operate a latching mechanism, which grasps the SCS lead within its lumen. The links 316 near the nitinol segment are deliberately made hollow to house a small axially magnetized ring magnet 332. All the ring magnets 332 within the body face the same direction (see Fig. 11) and will be used for locking the shape of the compound tube 312.

[0073] As shown in FIGS.12-14, an alternative compound tube 312’ includes ball-joints 336.

[0074] Referring back to FIG. 11, the nitinol tube 320 defines a length of 82 mm, an outer diameter (OD) of 4 mm, and an inner diameter of 3.4 mm, was machined using a Wire Electrical Discharge Machining unit (Additive Manufacturing Institute of Science and Technology, University of Louisville). A pattern of 1-mm rectangular notches, spaced 0.5 mm apart, were machined on either side of the nitinol tube in an alternating pattern to form bidirectional asymmetric joints that achieve 1-DoF bending. The nitinol tube 320 has two such 1-DoF bending joints, segment 340 (56.5 mm) and segment 344 (9.5 mm). Segment 340 primarily bends within the dorsal-ventral plane (of the patient’s body upon insertion), while segment 344 is restricted to the lateral plane by the rotated slit patterns by 90◦ around the nitinol tube 320. Three tendons (drive tendons) of 0.2 mm diameter were anchored to the nitinol body using knots around 0.7-mm notches at the distal end of each segment. Actuation of the tendons results in bending; 2 mm thick tendon routing brackets were 3-D-printed and attached to the nitinol body (using UV-glue) at every 12mm interval in segment 340 and in the middle of segment 344. Each tendon routing bracket houses six holes: one in the center to facilitate the electrode, and the rest for tendon routing (spread around the circumference of the bracket). The drive tendons were placed parallel to their anchor points,Attorney Docket No.11258-014WO1 while the tendons controlling the latching mechanism were offset from the lateral drive tendons by 27◦. The clearance in these brackets were much smaller than the compound tube at 0.1 mm. An alternate pattern of notches with 0.1-mm slits spaced 0.7 mm apart was evaluated.

[0075] A distal end of the nitinol tube 320 houses a spring-loaded latching mechanism 348 including four parts: an actuating set of jaws 352, a jaw guide 356, a spring 360 (spring constant = 1.8 N / mm), and a mounting bracket 364 for the spring 360. The actuating jaws 352 are a canister with a base on one side, to which tendons are attached, and four prongs with beveled edges on the opposing side. Each prong has a 0.202-mm notch extruded at the distal end contributing to increased compression and latching of the electrode. The jaw guide 356 sits outside the nitinol tube 320 and protrudes past the body by 0.9 mm in diameter. The upper chamber has a decreasing diameter based on an experimentally determined angle. The jaw guide 356 was printed using a Formlabs Form 3 using clear resin for its increased strength and resistance to deformation.

[0076] The actuating set of jaws 352 are pushed by the spring 360 into the walls of the guide 356 and are forced to clamp onto the electrode as the diameter of the guide 356 decreases. The latching mechanism 348 remains engaged as its ground state and the two tendons attached to the base of the jaws 352 are pulled to disengage the mechanism 348. In doing so, the spring 360 is compressed and the jaws 352 are moved to a location within the guide 356 with a higher diameter, thus freeing the electrode. Desirable function of the latching mechanism 348 depends on minimal axial compression of the ExoNav 300 body (since it interferes with the compression of the latching mechanism spring 360) as the latching mechanism tendons are pulled. Using this latching mechanism 348, the electrode is gripped tightly within the ExoNav 300 while it is navigated to a target location. Upon reaching the target, the tendons actuating the latching mechanism 348 are engaged, deploying the electrode at the target, while the ExoNav 300 can be retrieved to deploy more electrodes.

[0077] B. Backend Design

[0078] In the backend 308, the mechanism for operating the robot 300 involves the use of four dc motors 368 (φ8 mm, Maxon Metal Brushes, 0.5 W), which are affixed to a bracket at the rear of the backend 308 and powered by a 12 V dc power supply. Nominal speed and torque are 3490 rpm and 0.623 mNm, respectively. The motors 368 used for actuating drive tendons use a 1:64 planetary gearbox, while the motor 368 operating the latching mechanism 348 is paired with aAttorney Docket No.11258-014WO1 1:16 planetary gearbox. Each motor 368 is connected to a lead screw 372; by rotating this screw 372, a nut undergoes linear motion, facilitating the actuation of a 3-D printed part, to which a 0.2- mm nitinol tendon is attached. Along each lead screw 372, two 3-mm rods 376 and linear ball bearings 380 allow for precise linear motion. The device’s OD, set at 48 mm, facilitates ease of handheld operation. KINEMATIC MODEL

[0079] In this section, a geometric kinematic model is proposed to predict the shape of the robot 300. This kinematic model is built upon multiple assumptions based on the constant curvature assumption that has been proven to work well for modeling bidirectional asymmetric notched tubes, and the utilized design and manufacturing process of the robot 300. The bending curvatures for each part of the robot 300 (namely proximal and distal tubes) are constant, the axial compression of the tubes is insignificant, bending forces and moments generated by the corresponding tendons for lateral bending is independent of the ones for dorsal bending, and the proximal compound tube bends in the same direction as the distal nitinol tube 320.

[0080] The robot 300 is considered to have three different bending segments: the proximal compound tube 312, the distal nitinol tube 320 segment responsible for dorsal bending (in the sagittal plane of the patient’s body), and the distal nitinol tube 320 segment responsible for lateral bending (in the coronal plane of the patient’s body), and these different segments are denoted by subscripts 1, 2, and 3, respectively. Having these considerations in mind, the model is developed for two cases in the following.

[0081] A. Case 1: Dorsal Bending

[0082] In this case, segment 340 bends in its specific direction, and based on the fourth assumption previously mentioned, the proximal compound tube (segment 1) bends in the same direction as segment 340. On the other hand, the tendons to bend the robot to lateral directions are not actuated and consequently segment 344 remains straight throughout this case’s scenario. Each bending segment has its specific radius of curvature (ρ1 and ρ2) and degree of curvature (γ1 and γ2), as shown in FIG. 15. Geometrically, these bending curvature parameters are constrained as ρ1γ1= l1and ρ2γ2= l2, where l1and l2are the fixed segment lengths for the proximal segment and the lateral bending segment, respectively. Furthermore, a proportional relation between the two radii of curvature can be defined asAttorney Docket No.11258-014WO1 ρ2= μρ1(1) where 0 ≤ μ ≤ 1 is defined as the magnetic locking factor for dorsal bending. This factor equals 1 in the absence of magnetic locking effect. To relate the length of tendon stroke (ΔL) to the curvature parameters introduced previously, one can write the following geometrical equation: rt−1γ1+ rt−2γ2= ΔL (2) where rt−1 and rt−2 are the radii of the tendon routing channels, or in other words, the distance of tendons from the center-line of the robot in the subscripted segments, respectively (these dimensional parameters are measured as rt−1= 2.75mm and rt−2= 1.263 mm). By replacing the degrees of curvature in (2) by their alternative expressions, the following relation between ρ1 and ΔL (i.e., robot-independent kinematic model) is obtained:

[0083] Note that all the terms in (3) are known and fixed values, except for ρ1 and ΔL. ρ2 is also obtained simply by substituting the resulted ρ1into (1). Now that the robot-independent relations are obtained, the trajectory of an arbitrary point along the robot can be predicted in terms of the tendon stroke ΔL. However, to account for additional effects, a robot-dependent model is required. To develop this, geometry rules and relations will be used, and curvature parameters play an intermediate part between the tendon stroke ΔL and the position vectors p0i (superscript 0 determining that pi is expressed in the global fixed coordinate system F0). Based on the segment on which the arbitrary point piis defined, the equations used to obtain this position vector might change (due to different bending behaviors of different segments). Therefore, the arc-length of where the arbitrary point pi is defined depends on which segment pi is under consideration, and this will determine which equation has to be used. To do so, the subscript i will be 1, 2, and 3, while defined on the segments 1, 2, and 3, respectively. To obtain unified mathematical equations that deal with both rotation and translation of the coordinate frames simultaneously, all the position vectors and transformation matrices that come in the following are presented in the special Euclidean group (SE(3)).

[0084] First, we explicitly define a transformation matrix in SE(3)Attorney Docket No.11258-014WO1

[0085] where the matrix∈ ^^ ^^(3) is a rotation matrix that transforms the vectors defined in coordinate frame Fj suitably so that the resulted new vectors are expressed in coordinate frame Fk. Furthermore, ^^^^∈ ℝଷis the position vector (represented according to frame k axis directions) beginning from the origin of Fk and ending at the origin of Fj.

[0086] Now, let us consider the case when piis defined on the proximal compound tube (s ∈ [0,l1] where s is the arc length from the base of the robot, where the origin of the global coordinate frame F0is located, to the location where arbitrary point is positioned). In this case, the position vector p1 is defined based on geometric relations for arcs with constant curvature ^^^= ^ ^^ ൫1 − ^^ ൯ ^்^^ ఏభ^^^^ఏభ0 |1൧ (5)

[0087] Henceforth, the shorthand C and S will be used to indicate the cosine and sine functions, respectively. In (5), the degree of curvature between the origin of F0and the point p1is denoted by θ1. Without loss of generality, θiis defined as the degree of curvature between the origin of Fi−1and the point pi (i =1, 2, 3).

[0088] If the arbitrary point is defined on segment 340 (s ∈ [l1, l1 + l2]), the arbitrary point p2 can be expressed in the local coordinate system F1 as

[0089] thus to express p12 in the global coordinate frame F0, the following equation is used:^^ଶ^= ^^^^(− ^^^)^^ଶ^(7)

[0090] Ultimately, the case when the point is located on segment 344 (s ∈ [l1+ l2, l1+ l2+ l3]) is analyzed. Since the segment 344 does not bend in the case of dorsal bending, the expression for the position vector in the local coordinate system F2 is different from the one for p12 in (6)^^ଷଶ=^0 ^^ −(^^^ + ^^ଶ)0 |1^்(8)

[0091] which is expressed in coordinate system F0, using the following equation:Attorney Docket No.11258-014WO1^^ଷ^= ^^^^(− ^^^)^^^ଶ(− ^^ଶ)^^ଷଶ(9)

[0092] B. Case 2: Lateral Bending

[0093] In this case, the same approach as Case 1 is taken. Similar to the above-mentioned case, segment 1 bends in the direction of the total bending. Although, the difference appears in the other segments, where segment 340 stays straight while segment 344 bends to one of the lateral directions, as illustrated in FIG.16. Therefore, the proportional relation of the radii of curvatures for segments 1 and 3 is defines as ^^ଷᇱ= ^^ᇱ^^^ᇱ(10)

[0094] Similar to the magnetic locking factor introduced in (1), μ’ can take values between 0 and 1, with 1 used when the magnetic locking is not activated.

[0095] The global coordinate system F0is rotated about the y0axis and all the other coordinate frames are rotated suitably, so that the ziaxis (i = 1, 2) is orthogonal to the bending plane. The rotated coordinate systems are denoted as F’i i (i=0, 1, 2). The following translation matrix is utilized to rotate all the obtained position vectors back to the original coordinates orientation introduced above:

[0096] where β can be either 90◦ (if steering to the right direction while dorsal bending considered as steering upward) or −90◦ (if steering to the left, following the same assumption mentioned earlier).

[0097] Furthermore, for segment 344 lateral bending, position vectors pointing to the arbitrary point along the robot will be denoted by qji, with i and j used for the same purpose as discussed above. Note that the prime postscripts are used to determine whether the coordinate frame is a rotated one, or the curvature parameter is defined for lateral bending scenarios and the physical interpretation of these items are the same as their corresponding items discussed above.

[0098] Starting with position vector corresponding to an arbitrary location on segment 1 (s ∈ [0, l1]), a similar equation to (5) with suitable changes can be utilizedAttorney Docket No.11258-014WO1

[0099] Second, while the arbitrary point is located on segment 340 (s ∈ [l1, l1 + l2]), which will not bend in this case of the kinematic modeling, then the local position vector according to F’1 will be^^ଶ^=^0 ^^ − ^^^ 0 |1^்(13)

[0100] and to express this in the rotated global fixed coordinate system F’0, the following equation is used: ^^ଶ^= ^^^^(− ^^^ᇱ) ^^ଶ^(14)

[0101] Finally, to have the trajectory of the point located on segment 344 (s ∈ [l1 + l2, l1 + l2 + l3]), the local position of the arbitrary point is written as: ^ ^^ଷᇱ^^ଷᇱ^^ఏయ0 |1൧்ᇲ (15)

[0102] where θ’3 is the local degree of curvature that determines the location of the point q3 on segment 344. Similar to the approach taken for obtaining (9), one can get to the q3expressed in F’0usingEXPERIMENTS AND RESULTS

[0103] A. Latching Mechanism Experiments (Isolated)

[0104] To test the efficacy of the latching mechanism, multiple experiments were conducted independent of the nitinol body while changing two variables: the angle of the jaw guide, and initial spring compression, as seen in FIG. 17A. Three different angles (δ = 3.3◦, 5.5◦, and 7.7◦) and two levels of initial compression (0 and 1 mm compression) were examined throughout these experiments. The jaw guide angle of δ = 7.7◦ was the absolute maximum angle that could be accommodated before obstructing the electrode, while δ = 3.3◦ was the smallest angle to maintain tolerances between the latching mechanism and the guide while achieving latching. A total of 1 mm of compression was chosen to keep space for the latching mechanism to operate, travel, andAttorney Docket No.11258-014WO1 unlatch within the jaw guide. A series of four different tests were conducted to examine how the angle of the jaw guide and initial compression of the spring affected the latching mechanism’s functionality.

[0105] Test 1 examined the overall strength of the latching mechanism and used the following experimental setup: a load cell (MDB-55 lb capacity, Transducer Techniques) was attached to a linear actuating platform, while the latching mechanism was clamped onto a stationary platform, as illustrated in FIG.17A. The electrode was pulled by the load cell equipped actuating platform while the latching mechanism was engaged to observe the maximum force exerted before failure. In this test, the jaw guide with δ = 3.3◦, exerted the least amount of force (0.52 N). This jaw guide was outperformed by δ = 5.5◦ and δ = 7.7◦, which exerted 4.12 and 6.28 N, respectively, as seen in Table II and FIG. 17F. Jaw guides with these angles also experienced a self-tightening (ST) effect—as the electrode was pulled, the jaws were dragged further into the jaw guide leading to increased clamping. When the initial compression of the spring was decreased from 1 to 0 mm, all the guides experienced a significant reduction in clamping ability. The δ = 3.3◦ jaw guide showed little to no signs of clamping (0.04 N), while the δ = 5.5◦ jaw guide applied 0.36 N, and the δ = 7.7◦ jaw guide applied 0.80 N, as seen in Table I and FIG.17B (engaged). Along with the decrease in force, no signs of ST within the jaw guides were observed. Table 1 - force values of jaw guides using 0 mm initial compressionTable 2 - force values of jaw guides using 1 mm initial compressionAttorney Docket No.11258-014WO1

[0106] Test 2 quantified the unlatching force and validated the presence of ST. The experimental setup used was the same as test 1, rather, the load cell equipped platform pulled the latching mechanism tendons instead of the electrode. First, a baseline was established by recording the unlatching force without pulling the electrode. Next, the electrode was pulled until the latching mechanism failed and then the unlatching force was rerecorded. The unlatching force of δ = 3.3◦ jaw guide with ST was 2.20 N, however, in the absence of ST, latching was compromised and an unlatching value could not be derived. The unlatching force without ST for jaw guides with δ = 5.5◦ and δ = 7.7◦ was reduced by 2.27 and 1.5 N, respectively, as illustrated in Table II and FIG. 17F (unlatching force). The jaw guides with reduced initial compression experienced reduced unlatching forces and did not show any signs of ST. The δ = 3.3◦ jaw guide did not show any evidence of latching and did not have a specific force at which it unlatched. However, the δ = 5.5◦ jaw guide required 0.57 N to unlatch, and the δ = 7.7◦ jaw guide required 0.84 N to unlatch, as seen in Table I and FIG.17B (unlatching force).

[0107] In test 3, the strength of the latching mechanism without ST was examined. This test employed the same setup and procedure as test 1, however, the tendons attached to the internal jaws were anchored to the platform to prevent their further movement into the jaw guide and thus eliminating ST. Without ST, the δ = 5.5◦ and δ = 7.7◦ jaw guides exerted a peak force of 4.54 and 4.10 N, and stabilized at 2.66 and 1.86 N, as seen in Table II and FIG.17F (engaged w / o ST). The lower compression jaw guides and the high compression δ = 3.3◦ jaw guide were not tested since there was no evidence of ST. Finally, the design of the ExoNav requires minimal friction for easy passage of the electrode throughout the body. The last test examined the amount of friction applied on the electrode while the latching mechanism was disengaged. The setup used was the same as the first test, however, the tendons controlling the actuating jaws were pulled and anchored in order to disengage the latching mechanism. Among the 1 mm initial compression jaw guides, the δ = 3.3◦ jaw guide had the least amount of friction, at 0.19 N, while the δ = 5.5◦ and δ = 7.7◦ jaw guides exerted 0.26 and 0.22 N, respectively, as seen in Table II and FIG.17F (disengaged). The decreased compression jaw guides had consistently lower values of friction with all three jaw guides below 0.072 N, as seen in Table I and FIG.17B (disengaged).

[0108] B. Latching Mechanism (on Robot)Attorney Docket No.11258-014WO1

[0109] The latching mechanism was installed on the robot with the δ = 7.7◦ jaw guide and put through two tests to characterize interactions between the latching mechanism and the nitinol segment. First, the robot was clamped down to the test bench where the nitinol tube and the compound tube connect and the electrode was pulled to failure. Then, the robot was clamped at the tip behind the latching mechanism. The first scenario underperformed in comparison to the isolated tests, achieving a maximum force of 8.32 N, while the second scenario achieved a force of 9.74 N. Finally, the friction between the electrode and the overall body was tested by disengaging the latching mechanism and measuring the force while pulling the electrode. There was approximately 0.218N of force between the electrode and the robot.

[0110] C. Free Space Trial

[0111] The kinematic model proposed in above was validated in this section by conducting multiple experimental trials in free space under different circumstances. The experimental setup is illustrated in FIG.18A. Several optical markers were strategically placed along the ExoNav robot body and were tracked by four Vero v2.2 motion tracking cameras. In addition, three sets of markers were positioned at the in a fixed location to establish a global frame for the entire robot. The robot was installed on a stand in a vertical orientation to mitigate the influence of gravity on the initial shape of the robot.

[0112] These experiments were divided into four different parts, which include bending the robot in the dorsal direction with and without magnetic locking effect, and correspondingly, bending the robot laterally either to the left or to the right position with and without magnetic locking effect. The data gathered from these experiments were processed and compared with the kinematic model predictions in FIGS.18B-E. Using the gathered data, the magnetic locking factor was tuned and put equal to 0.6 (the same value was found for both factors μ and μ’). In addition, in a data-driven manner, tendon extension and dead-zone effects were characterized and added to the kinematic model. The kinematic model worked precisely in predicting the trajectory of the robot’s end- effector when the magnetic locking effect was not present, as depicted in FIGS. 18B and 18D. Although, while magnetic locking was effective, the kinematic model failed to predict the trajectory of the tip of the robot accurately, as seen in FIGS. 18C and 18E, which was probably due to nonlinear behavior of the magnets and uncertainty in selection of the magnetic locking factor value.Attorney Docket No.11258-014WO1

[0113] D. Active Oscillation and Magnetic Locking Effect

[0114] To illustrate the magnetic locking effect in compensating the movements of the proximal part of the ExoNav robot, a set of active oscillation trials were carried out. In these experimental trials the robot was forced to swing laterally by actuating the tendons in absence and presence of the magnetic locking effect. The position of the far-end part of the compound tube was tracked and compared throughout these trials. As seen in FIG. 18F, the magnetic locking mechanism successfully reduced the movements in X and Y directions. In addition, when the magnetic locking was effective, the undesirable movements along the z-axis almost decreased to zero. These undesirable movements in the z-axis were most probably due to slight imperfections in alignment of drive tendons routing channels. Note that the ideal locking mechanism keeps the far-end of the proximal compound tube in place, but due to the noncontact approach of the utilized locking mechanism and limitations in the applicable magnetic field, some motions are still visible (especially in the X direction). However, if these motions are small enough to guarantee a collision-free procedure, this magnetic locking effect can be acquired.

[0115] E. Experiment in the Spinal Cord Phantom

[0116] A neurosurgeon, who is also a co-author of this article, conducted timed trials to navigate the ExoNav and the standard SCS electrode around obstacles to a target in a phantom spinal cord (experimental setting with the ExoNav is shown in FIGS. 19-21). In trials with two obstacles, manual and robot trials took similar time (average time of 63.99 and 61.75 s, respectively), but manual trials had higher inconsistency with a standard deviation of 22.72 s (compared to 0.47 s) as the slightest differences in positioning caused greater difficulty for navigation. With three obstacles, manual trials were faster (average time of 24.18 s compared to 45.15 s) but as the surgeon became accustomed with navigating the obstacles, the time required for both methods of navigation improved (average manual time of 5.36 s and an average time of 16.23 s with the ExoNav). Finally, after training on this trajectory, a new trajectory was presented to the surgeon. In these trials the average time gap between manual (Average time of 17.7 s) and ExoNav (Average time of 24.72 s) was lower, although the manual approach was still faster.

[0117] This extended duration of trials with the ExoNav can be attributed to the high gearing of the drive motors (1:64) which limited the reachable linear velocity of the tendon pulling assembly (about 0.5 mm / s). In addition, the smaller diameter of the electrode (1.6 mm compared to 4.2 mm)Attorney Docket No.11258-014WO1 facilitated easier navigation through the obstacles. However, this trial was conducted simply as a proof-of-concept of the efficacy of our device in steering SCS electrodes. A rigorous expert surgeon trial with surgeon participants will be the subject of our future work. EXAMPLE 3

[0118] Below, the inventors provide another exemplary robotic guide system 400 referred to as the ExoNav 400. Extensive testing and design considerations are discussed below relative to the ExoNav 400 and shown in FIGS.22-23B.

[0119] A. Robotic Tool with Helical Cut Pattern

[0120] Two tubes form the ExoNav robot 400: A nickel-titanium (nitinol) inner tube 404, and a 3D-printed outer tube 408. The inner tube 404 is a machined nitinol tube with a specific quasi- helical micromachining pattern that allows the robotic tool to deform to a helical shape, allowing for FTL motion around the spinal cord. The quasi-helical micromachined pattern is generally spiral shaped so that the electrode can be moved from the back of the spinal cord to the front (and vice versa). The notch pattern machined along the tube 404 is a rectangular shape (0.4 mm by 2.8727 mm). Each rectangle is offset from the next one by 0.0287 mm along the circumference of the tube. These notches are made along the distal length of a nitinol tube 404 using a femtosecond laser (Optec WSFlex, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta) and the overall pattern resembles a helix drawn along the outer surface of the tube 404. A tendon is routed through the inner lumen of this tube and is fixed at the distal end to a 3D-printed cap placed at this end of the tube. Actuating this tendon will generated forces and moments at the tip of the robot thereby deforming it in a helical configuration.

[0121] The patterned nitinol tube 404 with its tendon installed is then placed inside a 3D-printed outer tube 408. This outer tube 408 inhibits deformation of that proximal section of the tube 404 that is within it. Therefore, the length of the tube 404 that is exposed out of the outer tube 408 can deform freely and the length that is within the outer tube 408 will remain undeformed. The length of the deformed portion of the ExoNav robot 400 can thus be changed by translating it through the outer tube 408.

[0122] B. Back-end Actuation and Control UnitAttorney Docket No.11258-014WO1

[0123] A back-end actuation unit 412 is made of two components responsible for generating the required FTL motion within the ExoNav robot 400. The first actuation component is a linear actuator 416 with a lead-screw 420 coupled to a DC motor 424 (RE 8 Ø8 mm, Precious Metal Brushes, 0.5 Watt, with terminals, Maxon international ltd., Switzerland) that can linearly move a bracket 428 along the installed steel rods. The second component is a 3D-printed 2-DoF roller gear 432 (ProJet MJP 2500, 3D Systems Inc.) with circumferential and longitudinal involute gear profiles 3D-printed that allow for simultaneous rotation and translation. The robot 400 is attached to the tip of a roller gear 436 as it is placed in its housing, which has two DC motors to control translation and rotation of the roller gear 436. The tendon controlling the inner tube 404 of the ExoNav robot 400 is routed at the middle if the roller gear 436 mechanism back to the linear actuator 416 and anchored to the moving bracket 428 which is equipped with a tendon tension sensor (MDB-5 force sensor, Transducer Techniques). A Texas Instrument LAUNCHXLF28379D LaunchPad is utilized to control the motors and gather force data in MATLAB / Simulink environment. KINEMATICS

[0124] In this section a forward kinematics model based on the geometric shape of a helix is presented. This model defines the relationship between actuation tendon stroke, the helical shape of the robot’s inner tube 404, and the position vectors to arbitrary points along the tube’s length. FIG.22 denotes geometric parameters critical to our kinematics model. Due to the quasi-helical pattern micromachined with rectangular notches within the inner tube, the portion of the tube that is left intact also forms a helical shape. We call this the ‘backbone’ of our helical joint. The total arc-length of this helical backbone is defined as lbb. The length lbb is assumed to be constant since the uncut intact side of the inner tube does not experience any compression or elongation while the tendon is actuated. The axial length of the machined portion of this inner tube is denoted by l and the radius of the tube is denoted as r. The fixed parameter lbbcan be expressed as a function of l and r and is given as follows:

[0125] Note, in developing this model, we assume for simplicity, that the inner tube makes one entire helical rotation around the spinal cord. However, in general, the number of turns the robotAttorney Docket No.11258-014WO1 can make around any arbitrary cylinder (proxy for the spinal cord) will be equal to the number of helical turns micro-machined within the nitinol tube.

[0126] A. Inner Tube Shape and Imaginary Cylinder

[0127] The shape of the inner tube 404 (and therefore the ExoNav robotic tool 400) is a function on the stroke of the actuating tendon. To obtain this function, we assume that the tendon is routed through the central axis of the inner tube and stays there while the ExoNav 400 is actuated and the tube deforms into a helix. Additionally, an imaginary cylinder which defines the overall shape of the robot is introduced. In other words, the dimensions of the imaginary cylinder (R and H, as shown in FIG.23A are obtained as a function of the tendon length lt.

[0128] Note that the central axis of the actuated robot is placed on the surface of the cylinder and the uncut side of the robotic tool is always facing away from the imaginary cylinder, therefore lbb relates to R and H as:

[0129] Since lbb is fixed, this equation shows there are specific combinations of R and H parameters that can be achieved with a specific robot design. Using Eqs.19 and 18, Radius of the imaginary cylinder is obtained.

[0130] By substituting the obtained parameter R into Eq.18, the height of the imaginary cylinder H is also obtained. Note that the length of the tendon ltcan be related to the tendon stroke value Δl as Δl = l − lt, and since all the other parameters involved are fixed values, the dimensions of the imaginary cylinder is derived purely from the tendon stroke input values.

[0131] B. Actuation and Deflection Angles

[0132] As it has been observed and demonstrated in FIG.23A, the robotic tool shows some sort of deflection from its straight configuration along its tail part and the outer tube. The angle of thisAttorney Docket No.11258-014WO1 deflection is denoted as ϕ (See FIG.23B). This angle is produced by the fact that the robotic tool must stay tangent to its tail part right where the robot is exposed out of the outer tube. Imagine if the imaginary cylinder was unwrapped to a 2D square, then the trajectory of the robotic tool is the same as the diagonal of that square. Noting the changes made in the square edge sizes as the imaginary cylinder changes, the deflection angle is understood to be equal to the angle between the robot trajectory (a.k.a., the square diagonal) and the edge that is equal to H. arctan

[0133] Additionally, there is another angle involved in determining the 3D shape of the robotic tool which is named the actuation angle and depicted as θ. As it is comprehended from its name, this angle θ is directly controlled by the roller gear’s rotational DoF, and it simply determines how much the robot has been rotated with respect to a fixed reference and which direction the robotic tool’s cuts that appear right out of the outer tube are facing. The actuation angle θ, along with the deflection angle ϕ are used to define the coordinate systems that help to obtain the shape and location of the robotic tool.

[0134] C. Position and Orientation in 3D space

[0135] As a fixed global coordinate system, O0 is defined at the tip of the outer tube and on the robotic tool’s back bone with axis X0pointed out and along the outer tube and with other axes directions being fixed. The local coordinate system O1is defined at the same location as O0and utilized to determine the actuation angle θ, therefore the axis Y1 is pointed from the point on the backbone towards the direction where the center of the cuts on the robotic tool appear right out of the outer tube, making an angle equal to θ with Y0(See Fig. 2(b)). With Y1facing the same direction as the cuts on the robotic tool, the center of the bottom circle of the imaginary cylinder is at the distance R+r from O1 along the direction of Y1. This location is where the coordinate system Ocis defined (See FIG.23B). In this coordinate system, Ycis pointed in the same direction as Y1, and Xc is defined along the imaginary cylinder central axis, hence making an angle equal to ϕ with X1 (See FIGS.23A and 23B). To determine any arbitrary point on the robotic tool backbone, an arc length parameter s is introduced which can take any values between 0 and lbb. Noting the directions of Ocaxes, the position vector in the aforementioned coordinates (cp(s)) is obtained as a function of arc length s.Attorney Docket No.11258-014WO1

[0136] To define this position vector in the fixed global coordinate system O0, one must apply a translation of R + r towards −Yc, a rotation of ϕ around Yc(giving the axis vectors of O1), and another rotation of θ around X1 (bringing us to O0). Completing these steps in the specified order gives^^ ^⃗^ ( ^^) the position vector of an arbitrary point on the robotic tool’s backbone defined in O0.

[0138] where C and S operators are cos and sin functions respectively, and ^^^ =

[0010] T.

[0139] D. Follow-the-Leader Motion

[0140] The roller gear’s translational DoF provides the capability to move the robotic tool in and out of the outer tube, therefore changing the constrained portion of the robotic tool at the back that cannot bend. We call this motion of the robotic tool “progressive motion”. There is a certain subset of possible progressive motions that matches the follow-the-leader motion characteristics. By using the proposed robot to perform follow the leader motion, actuation angle θ changes as the robotic tool is extended out of the outer tube in a way that the actuation angle θ stays constant, and simultaneously, tendon stroke Δl changes in a way to keep the deflection angle ϕ constant. By locking the values of these two angles, the location of the imaginary cylinder remains unchanged during the progressive motion, and based on the natural behavior of the helical curves, the body of the robotic tool keeps following its tip, hence performing a follow-the-leader motion.

[0141] To include the progressive motion in the kinematic model, a progression factor η is introduced, which determines the exposed portion of the robotic tool back bone out of the outer tube plbb with respect of its whole length lbb.plbb= ηlbb(25)Attorney Docket No.11258-014WO1

[0142] Note thatplbb, and consequently η, are directly controlled by the roller gear’s translational actuator. As the robot is moving out of the outer tube, the roller gear input angle θin= 2πη must change linearly with η to prevent θ from changing, basically keeping the immediate notches at the tip of the outer tube always facing the same side.

[0143] To maintain the constant deflection angle ϕ, the progressive tendon lengthplt= ηlt(the length of the tendon routed through the exposed portion of the robotic tool out of the outer tube) also needs to change linearly with the progression factor η. This way, total tendon stroke experienced by the robotic tool is:

[0145] For purposes of this description, certain advantages and novel features of the aspects and configurations of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed aspects, alone and in various combinations and sub-combinations with one another. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved.

[0146] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

[0147] Features disclosed in this specification (including any accompanying claims, abstract, and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The claimed features extend to any novel one, or any novel combination, of the featuresAttorney Docket No.11258-014WO1 disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0148] As used in the specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about”, it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. The terms “about” and “approximately” are defined as being “close to” as understood by one of ordinary skill in the art. In one non-limiting aspect the terms are defined to be within 10%. In another non-limiting aspect, the terms are defined to be within 5%. In still another non-limiting aspect, the terms are defined to be within 1%.

[0149] The terms “coupled”, “connected”, and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic. For example, circuit A communicably “coupled” to circuit B may signify that the circuit A communicates directly with circuit B (i.e., no intermediary) or communicates indirectly with circuit B (e.g., through one or more intermediaries).

[0150] Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “lower”, and “upper” designate direction in the drawings to which reference is made. The words “inner” and “outer” refer to directions toward and away from, respectively, the geometric center of the described feature or device. The words “distal” andAttorney Docket No.11258-014WO1 “proximal” refer to directions taken in context of the item described and, with regard to the instruments herein described, are typically based on the perspective of the practitioner using such instrument, with “proximal” indicating a position closer to the practitioner and “distal” indicating a position further from the practitioner. The terminology includes the above-listed words, derivatives thereof, and words of similar import.

[0151] Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises”, means “including but not limited to”, and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0152] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure.

Claims

Attorney Docket No.11258-014WO1 What is claimed is:

1. A robotic guide system for a medical device, the robotic guide system comprising: a first steering assembly including a first segment, a first tendon structured to actuate the first steering assembly in a first direction within a first plane, and a second tendon structured to actuate the first steering assembly in a second direction within the first plane; a second steering assembly including a second segment including bidirectional asymmetric notches, a third tendon structured to actuate the second steering assembly in a third direction within a second plane, and a fourth tendon structured to actuate the second steering assembly in a fourth direction within the second plane; and a latching device structured to selectively engage and release the medical device.

2. The robotic guide system of claim 1, wherein the first segment includes bidirectional asymmetric notches.

3. The robotic guide system of claim 1, wherein the first segment includes a quasi-helical micromachining pattern.

4. The robotic guide system of claim 1, wherein the first plane is normal to the second plane.

5. The robotic guide system of claim 1, wherein the first steering assembly is axially offset from the second steering assembly.

6. The robotic guide system of claim 1, further comprising: a first motor structured to actuate the first tendon; a second motor structured to actuate the second tendon; a third motor structured to actuate the third tendon; and a fourth motor structured to actuate the fourth tendon.

7. The robotic guide system of claim 6, further comprising: a first load cell associated with the first tendon and transmitting first loading information;Attorney Docket No.11258-014WO1 a second load cell associated with the second tendon and transmitting second loading information; a third load cell associated with the third tendon and transmitting third loading information; and a fourth load cell associated with the fourth tendon and transmitting fourth loading information.

8. The robotic guide system of claim 7, further comprising one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: receive the first loading information, the second loading information, the third loading information, the fourth loading information, and a user input; and control the first motor, the second motor, the third motor, and the fourth motor in response to the received information and the user input.

9. The robotic guide system of claim 1, wherein the latching device includes fingers movable between an open position configured to release the medical device and a closed position configured to engage the medical device.

10. The robotic guide system of claim 1, wherein the latching device includes torsional springs that bias the latching device toward an open position.

11. The robotic guide system of claim 1, wherein the latching device includes a latching tendon configured to be pulled to move the latching device toward a closed position configured to engage the medical device.

12. The robotic guide system of claim 1, further comprising: a locking system including a plurality of magnets positioned along an axial length of the robotic guide system; and a locking actuator configured to interact with the magnets of the locking system.Attorney Docket No.11258-014WO1 13. The robotic guide system of claim 12, wherein the locking actuator includes a pair of spaced magnets positioned to inhibit movement of the plurality of magnets of the locking system.

14. A robotic guide system for a medical device, the robotic guide system comprising: a first steering assembly including a first segment of bidirectional asymmetric notches, a first tendon structured to actuate the first steering assembly in a first direction within a first plane, and a second tendon structured to actuate the first steering assembly in a second direction within the first plane; a second steering assembly including a second segment of bidirectional asymmetric notches, a third tendon structured to actuate the second steering assembly in a third direction within a second plane, and a fourth tendon structured to actuate the second steering assembly in a fourth direction within the second plane; a locking system including a plurality of magnets positioned along an axial length of the robotic guide system; and a locking actuator configured to interact with the magnets of the locking system.

15. The robotic guide system of claim 14, wherein the locking actuator includes a pair of spaced magnets positioned to inhibit movement of the plurality of magnets of the locking system.

16. The robotic guide system of claim 14, wherein the first plane is normal to the second plane.

17. The robotic guide system of claim 14, wherein the first steering assembly is axially offset from the second steering assembly.

18. The robotic guide system of claim 14, further comprising: a first motor structured to actuate the first tendon; a second motor structured to actuate the second tendon; a third motor structured to actuate the third tendon; and a fourth motor structured to actuate the fourth tendon.Attorney Docket No.11258-014WO1 19. The robotic guide system of claim 18, further comprising: a first load cell associated with the first tendon and transmitting first loading information; a second load cell associated with the second tendon and transmitting second loading information; a third load cell associated with the third tendon and transmitting third loading information; and a fourth load cell associated with the fourth tendon and transmitting fourth loading information.

20. The robotic guide system of claim 19, further comprising one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: receive the first loading information, the second loading information, the third loading information, the fourth loading information, and a user input; and control the first motor, the second motor, the third motor, and the fourth motor in response to the received information and the user input.

21. The robotic guide system of claim 14, further comprising: a latching device including fingers movable between an open position configured to release the medical device and a closed position configured to engage the medical device.

22. The robotic guide system of claim 21, wherein the latching device includes torsional springs that bias the latching device toward the open position.

23. The robotic guide system of claim 21, wherein the latching device includes a latching tendon configured to be pulled to move the latching device toward the closed position configured to engage the medical device.

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