WO2024196833A2 - System and method for performing microvascular anastomosis - Google Patents

Abstract

A device configured to be used during a surgical procedure includes a vessel holder having a plurality of tines that are circumferentially-offset from one another. The tines of the vessel holder are configured to actuate between a radially-collapsed state and a radially- expanded state. The tines include nitinol.

Description

SYSTEM AND METHOD FOR PERFORMING MICRO VASCULAR

ANASTOMOSIS

Government Support

[0001] This invention was made with government support under grants EY032127, EB020610 awarded by NIH. The government has certain rights in the invention.

Cross-Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63/491,319, filed on March 21, 2023 and U.S. Provisional Patent Application No. 63/504,509, filed on May 26, 2023, which are incorporated by reference.

Field of the Disclosure

[0003] The present disclosure relates generally to systems and methods for performing a surgical technique that involves the joining of two luminal structures. More particularly, the present disclosure relates to systems and methods for performing microvascular anastomosis.

Background of the Disclosure

[0004] Anastomosis is a surgical reconstructive technique that involves the joining of two luminal structures. Vascular anastomosis (i.e., joining two blood vessels) can be particularly challenging, as small vessel diameters must be joined to form a leak-free connection that can withstand intraluminal blood pressures. In 1902, Alexis Carrel pioneered the field of vascular surgery by developing the first surgical technique to join two vessels. In his technique, Carrel triangulated the two vessels by equally placing three staging sutures around the vessel wall which were used to reapproximate and align the vessels so a continuous running stitch could be applied. This technique was later refined to include placing sutures using a patch technique whereby the lumen was opened so sutures could be easily placed along the tissue edge.

[0005] Despite recent advancements in surgical imaging, tools, and techniques that enable reconstructive microsurgery in vessels, microvascular anastomosis remains a challenge. More particularly, despite microvascular surgery being performed in the open setting under a microscope, inadequate visualization can lead to suturing of both walls of the vessel, while non-absorbable sutures and anastomotic leaks are responsible for complications such as early dehiscence (e.g., rupture) or late stricture which occur in up to 25-30% of visceral transplantation anastomoses. For even the most skilled surgeons, anastomotic thrombosis occurs in 0.5-10% of cases. These complications undermine the clinical outcomes, and diminish the quality of life for affected patients, and can make repeat surgery extremely difficult. Additionally, a single microvascular anastomosis may take more than 40 minutes to complete, which puts stress on time sensitive surgeries such as limb or organ transplantation.

Summary

[0006] A device configured to be used during a surgical procedure is disclosed. The device includes a vessel holder having a plurality of tines that are circumferentially-offset from one another. The tines of the vessel holder are configured to actuate between a radially-collapsed state and a radially-expanded state. The device also includes a sheath configured to actuate between a first position and a second position. The sheath in the first position is positioned around the tines of the vessel holder, which holds the tines of the vessel holder in the radially- collapsed state. The vessel holder and the sheath are configured to be inserted into a luminal structure. The sheath in the second position is withdrawn from the tines of the vessel holder, which allows the tines of the vessel holder actuate into the radially-expanded state to hold the luminal structure open.

[0007] A microvascular anastomosis positioning system (MAPS) is also disclosed. The MAPS includes a first clamp carrier configured to rotate around a first axis. The MAPS also includes a first clamp coupled to the first clamp carrier. The first clamp is configured to actuate between an open position and a closed position. A first luminal structure is configured to be inserted into the first clamp in the open position. The first clamp is configured to hold the first luminal structure in the closed position. The MAPS also includes a first vessel holder having a plurality of tines that are circumferentially-offset from one another. The tines of the first vessel holder are configured to actuate between a radially-collapsed state and a radially- expanded state. The first vessel holder is configured to rotate around a second axis. The MAPS also includes a first sheath configured to actuate between a first position and a second position. The first sheath in the first position is positioned around the tines of the first vessel holder, which holds the tines of the first vessel holder in the radially-collapsed state. The first vessel holder and the first sheath are configured to be inserted into a second luminal structure. The first sheath in the second position is withdrawn from the tines of the first vessel holder, which allows the tines of the first vessel holder actuate into the radially-expanded state to hold the second luminal structure open.

[0008] A system for performing a surgical anastomosis procedure is also disclosed. The system includes a macrovascular anastomosis positioning system (MAPS). The MAPS includes a clamp carrier configured to rotate around a first axis. The MAPS also includes a clamp coupled to and configured to rotate with the clamp carrier. The clamp is configured to actuate between an open position and a closed position. A first vessel is configured to be inserted into the clamp in the open position. The clamp is configured to hold the first vessel and to prevent blood flow through the first vessel in the closed position. The MAPS also includes a vessel holder having a plurality of tines that are circumferentially-offset from one another. The tines of the vessel holder are configured to actuate between a radially-collapsed state and a radially-expanded state. The vessel holder is configured to rotate around a second axis that is parallel to and laterally-offset from the first axis. The MAPS also includes a sheath configured to actuate between a first position and a second position. The sheath in the first position is positioned around the tines of the vessel holder, which holds the tines of the vessel holder in the radially-collapsed state. The vessel holder and the sheath are configured to be inserted into a second vessel. The sheath in the second position is withdrawn from the tines of the vessel holder, which allows the tines of the vessel holder actuate into the radially-expanded state to hold the second vessel open. The system also includes an imaging system configured to measure a parameter related to a position of a needle with respect to the vessel holder, the second vessel, or both.

Brief Description of the Figures

[0009] Figure 1A illustrates a perspective view of a surgical robot positioned over a microvascular positioning system (MAPS), according to an embodiment.

[0010] Figure IB illustrates a perspective view of the MAPS with an enlarged view of a vessel holder of the MAPS, according to an embodiment.

[0011] Figure 1C illustrates a perspective view of the surgical robot in a suturing position over the MAPS, according to an embodiment.

[0012] Figure 2A illustrates a perspective view of vessels being loaded into clamps of the MAPS, according to an embodiment.

[0013] Figure 2B illustrates a perspective view of the vessels being positioned over/around sheaths of the MAPS, according to an embodiment.

[0014] Figure 2C illustrates a perspective view of the sheaths being pulled back and allowing the vessel holders to expand inside the vessels, according to an embodiment.

[0015] Figure 2D illustrates a perspective view of the MAPS actuating to move the vessels between suturing positions, according to an embodiment. [0016] Figure 3A illustrates a top view of the MAPS showing motion during sheath actuation, according to an embodiment.

[0017] Figure 3B illustrates a front view of the MAPS showing motion during stage actuation, according to an embodiment.

[0018] Figure 4 illustrates a perspective finite element analysis (FEA) image of the vessel holder, according to an embodiment.

[0019] Figure 5 illustrates a schematic view of a workflow for semi-automatic placement of a suture during a (e.g., microvascular anastomosis) surgical procedure, according to an embodiment.

[0020] Figure 6 illustrates optical coherence tomography (OCT) imaging data being displayed during the surgical procedure, according to an embodiment.

[0021] Figure 7A illustrates sutured vessel spacing and bite depth measurements, according to an embodiment.

[0022] Figure 7B illustrates the sutured vessel after the sutures have been tied off, according to an embodiment.

[0023] Figure 8 illustrates graphs showing a coefficient of variance (COV) comparison between the surgical robot alone and the surgical robot combined with the MAPS, according to an embodiment.

[0024] Figure 9A illustrates a perspective view of a system (e.g., including the MAPS and surgical robot) that is configured to perform supervised autonomous microvascular anastomosis, according to an embodiment.

[0025] Figure 9B illustrates an enlarged portion of a portion of Figure 9A showing a suturing tool of the surgical robot, according to an embodiment.

[0026] Figure 9C illustrates an enlarged portion of a portion of Figure 9A showing the MAPS, according to an embodiment.

[0027] Figure 10 illustrates a perspective finite element analysis (FEA) image of a microvessel holder of the MAPS, according to an embodiment.

[0028] Figure 11 illustrates a perspective view of a microneedle tool of the surgical robot, according to an embodiment.

[0029] Figure 12 illustrates a microvascular suturing workflow for a single 1 mm vessel, according to an embodiment.

[0030] Figure 13 illustrates a schematic view of a network architecture of a feature-based multi-layer perception plus three-channel CNN for tissue type and edge detection, according to an embodiment. [0031] Figure 14 illustrates an OCT image-based tissue classification result using a featurebased network, according to an embodiment.

[0032] Figure 15A illustrates a perspective view of a cantilevered adjustable nitinol holder in a first state, and Figure 15B illustrates the cantilevered adjustable nitinol holder in a second state, according to an embodiment.

[0033] Figure 16 illustrates a perspective view of a notched wheel for holding suture ends, according to an embodiment.

[0034] Figure 17 illustrates a perspective view of the notched wheel in the MAPS, according to an embodiment.

[0035] Figure 18 illustrates another perspective view of the notched wheel in the MAPS, according to an embodiment.

Detailed Description

[0036] Robotic Vessel Positioning System for Semi-Automatic Microvascular Anastomosis

[0037] The present disclosure provides a system and method for positioning tissue with an integrated suturing robot and performing semi-automatic anastomoses of (e.g., real or synthetic) blood vessels. A finite element analysis-based design consideration was used for achieving adequate grasping of the blood vessels and to demonstrate robust performance under expected clinical forces. Standardized positioning tests were then performed to measure the repeatability. The tests incorporated a high-resolution optical coherence tomography (OCT) fiber imaging sensor within the tip of the suturing tool to provide position feedback of the robot during a suturing task. Using the microvascular positioner and OCT sensor, the system performed semi-automatic suturing of synthetic 5 mm diameter blood vessels (N=4), and the suture quality was evaluated for consistency in spacing, bite depth, percent lumen reduction, and maximum suture strength. The system completed the task in an average time of 31.75 minutes. The samples had zero missed stitches, average spacing of 1.64 mm, an average bite depth of 2.14 mm, an average lumen reduction of 57.98%, and an average suture strength of 3.13 N.

[0038] More particularly, the system and method introduce a microvascular anastomosis positioning system (MAPS) that can be integrated with a surgical robot, such as Smart Tissue Autonomous Robot (STAR), to enable semi-automatic anastomoses of vessels less than or equal to 5 mm in diameter, 3 mm in diameter, or 1 mm in diameter. The MAPS is a robotic tool for manipulating blood vessels which enables vessel suturing with the surgical robot. [0039] The present disclosure describes the design and development of the MAPS, which is capable of grasping and positioning (e.g., real or synthetic) blood vessels, as shown in Figures 1A-1C. More particularly, Figure 1A illustrates a perspective view of a surgical robot 160 positioned over the MAPS 100, Figure IB illustrates a perspective view of a portion of the MAPS 100 with an enlarged view of a vessel holder 150B of the MAPS 100, and Figure 1C illustrates a perspective view of the surgical robot 160 in a suturing position with an imaging fiber 170, according to an embodiment. Performance of the MAPS 100 is reported including finite element analysis (FEA) and repeatability of positioning.

[0040] As described in greater detail below, the MAPS 100 may include a first stage 115A. The first stage 115A may include a first clamp carriage 120A that is configured to move. For example, the first clamp carriage 120A may rotate around a first central longitudinal axis 122A extending therethrough. The first stage 115A (e.g., the first clamp carriage 120A) may include a first clamp 130A that is configured to actuate between an open position and a closed position. A first luminal structure (e.g., vessel) 110A is configured to be inserted into the first clamp 130A in the open position, and the first clamp 130A is configured to hold the first luminal structure 110A and to prevent blood flow through the first luminal structure 110A in the closed position. The luminal structures described herein may be blood vessels, nerves, bowels, urethras, ureters, or other tubular structures.

[0041] The first stage 115A may also include a first vessel holder 150A that includes a plurality of tines that are circumferentially-offset from one another around a second central longitudinal axis 122B. The first and second axes 122A, 122B may be parallel to and/or laterally-offset from one another. The tines of the first vessel holder 150A are configured to actuate between a radially-collapsed state and a radially-expanded state. The tines may be straight, angled, or curved.

[0042] The first stage 115A may also include a first sheath 140A that is configured to actuate between a first position and a second position. The first sheath 140A in the first position is positioned around the tines of the first vessel holder 150A, which holds the tines of the first vessel holder 150A in the radially-collapsed state. The first sheath 140A in the second position is (e.g., axially) withdrawn from the tines of the first vessel holder 150A, which allows the tines of the first vessel holder 150A to actuate into the radially-expanded state.

[0043] The MAPS 100 may also include a second stage 115B. The second stage 115B may include a second clamp carriage 120B that is configured to move. For example, the second clamp carriage 120B may rotate around the second central longitudinal axis 122B. The second stage 115B (e.g., the second clamp carriage 120B) may include a second clamp 130B that is configured to actuate between an open position and a closed position. A second vessel HOB is configured to be inserted into the second clamp 130B in the open position, and the second clamp 130B is configured to hold the second vessel HOB and to prevent blood flow through the first vessel 110B in the closed position. In one embodiment, the first and second vessels 110A, 110B may be different portions of the same vessel (e.g., that has been cut or severed). In another embodiment, the first and second vessels 110A, 110B may be different vessels that are to be joined (e.g., as part of a transplant procedure).

[0044] The second stage 115B may also include a second vessel holder 150B that includes a plurality of tines that are circumferentially-offset from one another around the first central longitudinal axis 122A. The tines of the second vessel holder 150B are configured to actuate between a radially-collapsed state and a radially-expanded state.

[0045] The second stage 115B may also include a second sheath 140B that is configured to actuate between a first position and a second position. The second sheath 140B in the first position is positioned around the tines of the second vessel holder 150B, which holds the tines of the second vessel holder 150BA in the radially-collapsed state. The second sheath 140B in the second position is (e.g., axially) withdrawn from the tines of the second vessel holder 150B, which allows the tines of the second vessel holder 150B to actuate into the radially-expanded state.

[0046] As described in greater detail below, the first vessel 110A is configured to be positioned around the second sheath 140B and the second vessel holder 150B when the second sheath 140B is in the first position. The second sheath 140B in the second position is withdrawn from the tines of the second vessel holder 150B, which allows the tines of the second vessel holder 150B actuate into the radially-expanded state to hold the first vessel 110A open. The second vessel holder 150B and the first clamp carriage 120A are configured to move (e.g., rotate simultaneously) to rotate the first vessel 110A between different suturing positions. The first vessel 110A, the first clamp carriage 120A, the first clamp BOA, the second sheath 140B, the second vessel holder 150B, or a combination thereof may be substantially aligned (e.g., around the axis 122A) as the first vessel 110A is rotated.

[0047] Similarly, the second vessel 110B is configured to be positioned around the first sheath 140A and the first vessel holder 150A when the first sheath 140A is in the first position. The first sheath 140A in the second position is withdrawn from the tines of the first vessel holder 150A, which allows the tines of the first vessel holder 150 A actuate into the radially- expanded state to hold the second vessel 110B open. The first vessel holder 150A and the second clamp carriage 120B are configured to move (e.g., rotate simultaneously) to rotate the second vessel HOB between different suturing positions. The second vessel HOB, the second clamp carriage 120B, the second clamp 130B, the first sheath 140A, the first vessel holder 150A, or a combination thereof may be substantially aligned (e.g., around the axis 122B) as the second vessel 110B is rotated. The first vessel 110A, the first clamp carriage 120A, the first clamp 130A, the second vessel sheath 140B, the second vessel holder 150B, or a combination thereof may be misaligned with the second vessel 110B, the second clamp carriage 120B, the second clamp 130B, the first sheath 140A, the first vessel holder 150A, or a combination thereof as the first and second vessels 110A, 110B are rotated.

[0048] The MAPS 100 was designed using Fusion 360 (Figure IB). Smaller plastic components such as a clamp carriage and pulleys may be 3D printed using an Anycubic Photon SLA printer and photopolymer resin. Larger components such as the housing may be printed with PL A on a Creality CR-10 V2 FDM printer.

[0049] The system and method also integrate the MAPS 100 with the surgical robot 160 to create a microvascular suturing system. The optical coherence tomography (OCT) fiber image sensor 170 may be used for positioning feedback between the MAPS 100 and the surgical robot 160 so that the needle trajectory is aligned correctly with the blood vessel 110. Finally, the overall system was evaluated by performing semi-automatic vessel anastomosis in synthetic vascular grafts (N=4). The quality of the suture line was evaluated for consistency in suture spacing, suture bite depth, percent luminal reduction, and mean tensile strength which was shown to be within clinical requirements.

[0050] Materials and Methods

[0051] MAPS Design

[0052] During microvascular anastomosis procedures, as performed in many transplant procedures, the surgeon may use a double approximator clamp to hold the vessels while suturing in an open surgical setting under an operating microscope. The clamps on either side of the approximator may be used to prevent blood from flowing into the vessel while suturing is performed in between them. Once the sutures on the front half of the vessel are complete, the approximator clamp may be flipped over 180 degrees, rotating the vessels, and allowing the surgeon to suture on the back half. The robot design described herein rotates the vessels 120 to access suture positions. Because the procedure is performed in an open setting, the MAPS’ form factor may be larger, with physician interviews confirming it was appropriate for the surgical scene.

[0053] Figures 2A-2D illustrate a workflow of the MAPS 100. The first vessel 110A may be inserted into the first clamp I 30A, and the second vessel 110B may be inserted into the second clamp 130B, as shown in Figure 2A. In one embodiment, the clamp carriages 120A, 120B and clamps 130A, 130B may be positioned such that the vessels 110A, HOB are axially- aligned when inserted into the clamps 130 A, 13 OB.

[0054] Next, the clamp carriages 120A, 120B may move (e.g., rotate) such that the vessels 110A, HOB are no longer axially-aligned, as shown in Figure 2B. Rather, the first vessel 110A may now be axially-aligned with the second sheath 140B, and the second vessel 110B may now be axially-aligned with the first sheath 140 A. The first vessel 110A may then be positioned around the second sheath 140B, and the second vessel 110B may be positioned around the first sheath 140 A.

[0055] Next, the second sheath 140B may be axially-retracted from the first vessel 110A, and the first sheath 140A may be axially-retracted from the second vessel 110B, as shown in Figure 2C. Axially-retracting the sheaths 140A, 140B may expose the vessel holders 150A, 150B that were positioned within the sheaths 140 A, MOB. Thus, the second vessel holder 150B may be positioned within and may expand and grip the interior of the first vessel 110A. Similarly, the first vessel holder 150A may be positioned within and may expand and grip the interior of the second vessel 110B. In one embodiment, the clamps 130A, 130B may then be opened to release the vessels 110A, 110B. A first suture may be placed in the vessels 110A, HOB.

[0056] Next, the clamp carriages 120A, 120B and the vessel holders 150A, 150B may rotate (e.g., simultaneously) to rotate the vessels 110A, 110B to a different (e.g., second) suturing position, as shown in Figure 2D. A second suture may then be placed in the vessels 110A, 110B at a different circumferential location in the vessels 110A, 110B. This process may be repeated to place additional sutures.

[0057] Figures 3 A and 3B illustrate a top view and a side view of the MAPS 100, according to an embodiment. Each stage 115A, 115B of the MAPS 100 may be driven using one or more motors (e.g., two stepper motors). The first motor (i.e., the sheathing motor) rotates a pulley 310 attached to its shaft, as shown in Figure 3 A. Rotating the pulley 310 actuates either the left or right cable. Each cable may be attached to the sheath and wrapped around a pulley on either end of the travel. Then, when the stepper motor actuates, the vessel holder 150A may be either sheathed or unsheathed. A limit switch on either end of the sheath’ s travel may inform the system 100 when to stop.

[0058] The second stepper motor may drive the rotation of the clamp carriage 120 A and the vessel holder 150A together. The second motor rotates a pulley 320 which may be attached to two pull wires, as shown in Figure 3B. These pull wires may be coupled to a corresponding pulley in the device. When the second motor is actuated, the pulley in the device may be rotated. The pulley may be attached to a shaft along with a (e.g., 25-tooth) gear. This gear may drive a larger (e.g., 56-tooth) gear, also called the large gear, which may be fixed to the vessel holder 150A. An encoder may be mounted to the vessel holder 150 A on the outside of the housing, which allows the system to track the orientation of the vessels 110A, HOB and/or the vessel holders 150A, 150B.

[0059] To ensure that the clamp 130A rotates in unison with the vessel holder 150A, the clamp 130A may be attached to the clamp carriage 120 A, which has a circular slot which allows it to rotate in the device housing. On the outside of the clamp carriage 120A, a geared edge with 56 teeth may engage and match the large gear. To ensure the top of the clamp I 30A is accessible, the teeth may not cover the full circumference. Because of this, the clamp carriage 120A may have fewer (e.g., only 37) teeth but maintain the same spacing and pitch diameter as the large gear. The large gear may rotate a smaller (e.g., 25-tooth) gear, which drives the clamp carriage 120A. To ensure that the clamp carriage 120A continues to be driven when the 25-tooth gear is not engaged with the teeth of the clamp carriage 120A, another gear on the opposite side of the clamp carriage 120A may also drive the clamp carriage 120A. This gear may be rotated by a belt and a small series of gears under the clamp carriage 120 A, which synchronize the left 25-tooth gear with the right 25 tooth gear.

[0060] Each stage 115A, 115B may be controlled by a controller (e.g., Arduino Mega 2560), which controls two (e.g., TMC 2130) stepper motor drivers. The limit switch and encoder may be connected to the controller, and the MAPS 100 may be controlled by breadboard buttons. There may be 5 buttons for controlling each half of the system. In an example, these buttons may include: sheath toggle, rotate clockwise 45°, rotate counterclockwise 45°, rotate clockwise 1°, and rotate counterclockwise 1°. One 45° rotation may move the system from one suture position to the next, while the 1° rotation may be used to fine-tune the position.

[0061] Vessel Holder

[0062] Figure 4 illustrates a perspective view of a finite element analysis (FEA) of the vessel holder 150A, according to an embodiment. As discussed above, the vessel holder 150A may hold the vessel HOB open from the inside, providing counterforce for the needle to pass through the tissue without puncturing the opposite wall of the vessel 110B. In one embodiment, the vessel holder 150A may be made from nickel titanium (i.e., nitinol). For example, the vessel holder 150A may be made from a laser-cut nitinol tube which has been heat-set to an expanded position. Gaps 154 between each circumferentially-adjacent pair of the tines 152 provides space for the needle and helps to ensure the consistency of suture spacing. The vessel holder 150A may have from about 4 gaps to about 16 gaps (e.g., 8 gaps for 8 sutures to be placed). Because of the super-elastic properties of the nitinol, the vessel holder 150A may be positioned into a much smaller-diameter sheath 140 A, allowing for easy vessel loading over the vessel holder 150A. Once unsheathed, the vessel holder 150A may expand inside the vessel HOB, holding it from the inside.

[0063] To ensure the vessel holder 150A meets the clinical needs of the suturing procedure, radial force and puncture force measurements were taken from the synthetic blood vessels that were also used for feasibility testing. 3-Dmed synthetic tissues offer similar suturing and elasticity properties to real tissue. These results were used to define finite element analysis (FEA) loads in simulation, which enabled the design of the vessel holder 150A to be optimized to have the smallest possible outer diameter (OD) while still adequately supporting the vessel HOB during suturing. Other design constraints may include availability of stock nitinol components, laser cut width, manufacturability, and the force required to sheath the nitinol. The resulting collapsed vessel holder 150A may have about 50% of the diameter of the vessel 110B which enables easy insertion into the vessel 110B.

[0064] The puncture force was tested with the vessel 110B stretched to a range of diameters, but no relationship was found between expansion and force. The analysis used the maximum recorded force value of 0.31 N and added a 20% safety buffer. Hence, the force used for analysis was 0.37 N.

[0065] The vessel 110B was pressurized with saline, and the correlated OD was measured throughout. The pressure results were used to calculate a linear regression, which enabled estimation of radial pressure on the vessel holder 150A when the tissue was expanded to a given diameter. The resulting linear equation (1) had an R² value of 0.93. The vessel OD was measured in mm, and pressure was in kPa.

Vessel OD = 0.0715 * Pressure + 4.9275 (1)

[0066] During optimization in FEA, an expanded OD of 5.5 mm was selected to minimize OD and deflection. By plugging 5.5 mm into the linear regression, and adding a 20% buffer, this produced an anticipated radial pressure of 9.61 kPa.

[0067] Using the calculated radial pressure and maximum puncture force, the loads in the model were defined for FEA. The radial pressure was applied to the OD of the vessel holder tines 152 where the vessel 110B would be loaded, and the puncture force was applied to the approximate suture site (8.5 mm along the length of the tines). The results are shown in Figure 4. The maximum deflection was 0.38 mm, and the deflection at the puncture force location was 0.20 mm. This deflection is anticipated to be acceptable for performing the suture. [0068] Surgical Robot Integration

[0069] Suturing may be performed using the surgical robot (e.g., the STAR system) 160. The surgical robot 160 may include a circular needle drive that is compatible with a 2-0 and/or 3-0 polyester suture. The control workflow used a high-level task planner so that an operator may control the surgical robot 160 in a semi-automatic mode. The workflow combined a sequence of robot motions that traverse pre-planned points as well as stitch placement routine. A total of 8 points may be taught prior to the procedure and preloaded to the task planner. The operator may then specify the point sequence of execution in the high-level task planner and define the automatic sections of the robot motion. When executing the routine, the system may pause the task planner prior to suturing so that alignment of the suturing tool and target tissue (e.g., vessel 110A, HOB) may be verified with the integrated OCT imaging. Once the operator confirms the position of the suturing tool, the system may apply a suture, and the task planner resumes automatic motion along the pre-planned points. For low-level motion planning of the surgical robot, point-to-point and/or linear motion may be interpolated with smooth trajectories. The Cartesian trajectory may be transformed to waypoints in joint space via inverse kinematics.

[0070] OCT Imaging

[0071] The system may use common-path optical coherence tomography (OCT) to provide real-time positioning feedback of the suturing tool with respect to the vessel 110A, HOB and the tines 154 of the vessel holders 150A, 150B. The signal may be acquired using a singlemode fiber 170 (see Figure 1C) that is connected to a swept-source OEM engine, a broadband mini optical attenuator, a broadband circulator, a Camera-Link frame grabber, and a laptop. The interference signal may come from the sample and the interface between the fiber 170 and the outside medium. The original spectrum data may be sampled by a frame grabber and processed in parallel with a discrete graphics card on the laptop to achieve the sensing speed (e.g., 100 kHz). By combining the sample and reference beam with the same single-mode fiber 170, the system may be resistant or immune to dispersion and polarization noise. The OCT fiber imaging sensor 170 was integrated into the suturing tool by gluing the single mode fiber 170 within a stainless-steel hypo-tube that may be embedded within a distal sleeve, as shown in Figure 1C. The sleeve may be oriented such that the fiber 170 is co-planar with the path of the suturing needle and aligned the OCT signal with the target tissue. The center wavelength may be about 1060 nm with an output power of about 2 mW, which provides an axial resolution of 4.5 pm with a scanning depth of 3.7 mm in air.

[0072] Semi-Automatic Suture Placement Workflow [0073] Figure 5 illustrates a schematic view of a workflow for semi-automatic placement of a suture, according to an embodiment. The workflow includes manual tasks (e.g., load vessels 110A, HOB, tie sutures, adjust the MAPS 100) and tasks performed semi-automatically (e.g., rotate, move, image, suture). The workflow described is for a single suture throw and is repeated (e.g., a total of sixteen times) for the complete anastomosis. The procedure begins with the surgical robot 160 at a home position while the operator manually loads two vessels 110A, HOB onto the MAPS 100. Next, the surgical robot 160 automatically moves the suturing tool to the first suture location on the left vessel 110B. When at the suturing position, the operator observes the OCT imager and determines whether the MAPS 100 should be used to perform positioning adjustments to the orientation of the blood vessel 110B. The MAPS 100 may be used to apply fine rotational adjustments (e.g., 1°) to correct any errors in positioning. After confirming the needle location, the robot 160 applies the first throw, then automatically moves to the right vessel 110A, and waits for (e.g., manual) confirmation to apply the second throw. After both suture throws have been completed, the surgical robot 160 automatically moves back to the home position while the operator uses the MAPS 100 to rotate the vessels 110A, 110B (e.g., 45°). The suture routine may then be repeated, and knots may be tied manually after all sutures have been thrown.

[0074] Experiments and Results

[0075] Repeatability of Stage Rotation

[0076] To test the repeatability of the system, the MAPS rotation stage may be rotated in 45° increments through the full motion of the robot. This may include starting at the zero position, rotating 180° in one direction, 360° in the opposite direction, and then back 180° to the starting point. This resulted in 16 steps for the full motion. The angle between each increment may be recorded. For the left stage, the average was 44.51°, and there was a standard deviation of 2.08°. For the right stage, the average was 49.31°, and there was a standard deviation of 9.68°. [0077] OCT Imaging Feedback

[0078] During the anastomosis procedure, the operator may be able to determine if the OCT, which is aligned with the plane of the needle, is above just air, tissue, vessel holder, or both tissue and nitinol. An example of the OCT output is show in Figure 6 with the vessel holder signal identified by arrows.

[0079] Suture Testing with Surgical Robot System

[0080] To setup the entire system, the MAPS 100 may be fixed onto a table in the field of the surgical robot (e.g., STAR) system 160, as shown in Figure 1A. A test vessel may be loaded into the system and may be used for reference to teach the surgical robot 160 all the points in the workflow. The OCT display may be setup in view of the operator to allow the operator to use the feedback from the OCT to adjust the spacing of the sutures before passing the needle. Every 4 sutures, as the suture is depleted, the needle and suture may be replaced.

[0081] For evaluating the setup, four anastomoses were performed on synthetic vessel samples, placing 8 sutures in each vessel. Any adjustments to the spacing based on OCT feedback were recorded. For the right stage of the MAPS 100, the average angulation adjustment per stitch was 0.97°. For the left stage, the average angulation adjustment per stitch was 0.16°.

[0082] Beginning and end times of the trials were recorded. The procedure duration ranged from 27 to 35 minutes with an average of 32 minutes. The anastomosis duration was faster compared to clinical anastomoses ranging from 40 to 75 minutes. The system successfully placed 64 consecutive sutures without missing the vessel tissue, crossing, or tangling suture threads. No sutures missed the vessel or punctured both walls. Additionally, no stretching, tearing, or other trauma was observed from the MAPS handling the tissue.

[0083] Suture Spacing and Bite Depth

[0084] Pictures of sutured vessels 110A, HOB were taken, and measurements of suture spacing and bite depth were recorded. Examples of the sutured vessel 110A, HOB are shown in Figure 7 where suture spacing is defined as the distance between two consecutive sutures 710A, 710B, and bite depth is the shortest distance from the point of a suture 170 A, 170B on the vessel wall to the cut edge. For spacing and bite depth, the averages were 1.64 mm and 2.14 mm, respectively. The standard deviations were 0.34 mm and 0.76 mm, respectively. An ideal suture spacing for the tissue was 1.77 mm.

[0085] To compare the vascular suturing performance to past anastomoses with the surgical robot, the data may be normalized by dividing the average suture spacing and average bite depth by their respective standard deviations to obtain the coefficient of variance for each metric (COV). The COV for microvasculature suturing was calculated to be 20.9% for spacing and 35.6% for bite depth. Prior studies using the surgical robot 160 without using the MAPS 100 had achieved a COV of 26.36% for spacing and 29.99% for bite depth. Using Forkman’s method and a statistical significance level of 0.05, it was found that the surgical robot 160 had more consistent suture spacing with the MAPS 100 (p = 0.045), while no significant difference in bite depth was observed (p = 0.113) (see Figure 8).

[0086] Lumen Reduction

[0087] After spacing and bite depth measurements were taken, the sutures 710A, 710B were manually tied off using a surgeon’s knot. Pictures were taken of the cross-section of each anastomosis and one non-sutured vessel sample. The percentage in reduction in area was then calculated (TABLE I).

TABLE I. LUMEN REDUCTION MEASUREMENTS

[0088] Pull Force

[0089] Each of the anastomosis samples were tensioned in a tensile tester at a strain rate of 1 mm/second along with one intact synthetic vessel sample and one hand-sutured sample. The peak forces are recorded in TABLE II.

TABLE II. PULL FORCE TESTING SUMMARY

[0090] Other studies have measured the tensile strength of a hand-sutured anastomosis to be 3.64 N with a standard deviation of 2.2 N when using porcine coronary arteries. All the pull force results were well within one standard deviation of porcine artery data. Therefore, anastomoses from the MAPS 100 produce sufficient tensile strength.

[0091] The MAPS 100 successfully performed 4 anastomoses when paired with the surgical (e.g., STAR) robot 160 and OCT fiber imaging sensor 170. When compared to previous surgical robot studies (e.g., without the MAPS 100), the MAPS 100 reduced variance in suture spacing, but not in bite depth. This was due to bite depth placement being driven by preprogrammed points and not adapting to the tissue placement. OCT was shown to differentiate between air, tissue, vessel holder, and tissue over vessel holder. Integrating OCT into the control loop allowed the MAPS 100 and the surgical robot 160 to automatically position the suture 710A, 710B relative to the tissue (e.g., vessel 110A, HOB). Changes to encoder mounting may improve repeatability and modify the outer surface of the vessel holder 150A, 150B with etching or coatings that are used in other cardiovascular devices would improve vessel grip.

[0092] Leak testing may be performed to demonstrate the efficacy of this system. However, in place of this test, the pull force test was performed and sufficient tensile strength was shown. Additionally, the percent lumen reduction was considered as a marker for clinical success. Using the MAPS 100, the average lumen reduction of the resulting anastomoses was 57.98% with the maximum being 61.43%. However, research indicates that arteries can be reduced up to 70% while maintaining laminar flow. Additional data found a 5 mm canine artery can be reduced by up to 90% before blood flow is reduced by 50%. While studies seem to indicate lumen reduction of 57.98% may be acceptable, efforts should be applied to reduce this in future iterations. Tighter control of bite depth using OCT may help minimize lumen reduction.

[0093] In summary, the MAPS 100 successfully performed vascular anastomosis with minimal human intervention in 5 mm vessels. This size is applicable to femoral and brachial artery surgery. While 5 mm vessels were used in this study due to limitations with the size of surgical robot’s needle driver, the system and method may also be used to perform anastomosis of smaller vasculature, such as 1 mm vessels encountered in maxillofacial and head and neck reconstruction (e.g., using a 9-0 suture). Notably, high resolution OCT imaging shows promise to make the system fully automatic and more accurate. A feedback control loop where OCT data is used to inform correct suture placement may enable a fully autonomous system in future studies with the MAPS 100.

[0094] Robotic System for Microvascular Anastomosis

[0095] Figure 9A illustrates a perspective view of a system configured to perform supervised autonomous microvascular anastomosis, Figure 9B illustrates an enlarged portion of a portion of Figure 9 A showing the suturing tool 162 of the surgical robot 160, and Figure 9C illustrates an enlarged portion of a portion of Figure 9A showing the MAPS 100, according to an embodiment. The system shown in Figure 9A may improve microvascular anastomosis outcomes by addressing the technical and clinical limitations that contribute to anastomotic complications such as leaks. The system operates by using micron resolution optical coherence tomography (OCT) imaging to guide the orientation of a microneedle suturing tool 162 attached to a robotic arm of the surgical robot 160, as shown in Figure 9B. Vessel apposition under the suturing tool 162 may be accomplished by a micro tissue positioning stage, as shown in Figure 9C, and the anastomosis may be performed under the supervision of a surgeon through a surgical microscope. The system is first evaluated in synthetic and ex vivo vessels, followed by first in animal preclinical studies to demonstrate the safety and feasibility of end- to-end microvascular anastomosis prior to human trials.

[0096] Autonomous robotic microvascular anastomosis has yet to be demonstrated due to a lack of (a) precise and atraumatic tissue manipulation, (b) miniaturized robotic tools that simplify suture motion, and (c) high resolution image guidance with intraoperative tissue assessment. However, the present disclosure describes a new system and method that improve microvascular anastomosis outcomes by developing a precision vessel holder that safely clamps and manipulates microvasculature (Aim 1), a robotic micro-needle driver to robustly apply miniature interrupted sutures (Aim 2), and high-resolution optical coherence tomography (OCT) guidance using artificial intelligence (Al) interpretation (Aim 3). The system may be evaluated in synthetic and ex vivo vessels, followed by preclinical studies to demonstrate and compare the safety and efficacy of supervised autonomous microvascular anastomosis.

[0097] The MAPS 100 shown in Figure 9C provides precise tissue orientation and reapproximation. The MAPS 100 may include the clamps 130A, 130B to temporarily restrict blood flow, and super-elastic (e.g., nitinol) vessel holders 150A, 150B that insert into the vessel’s lumen. The vessel holders 150A, 150B may automatically deploy to open the vessel 110A, HOB and provide counter tension during suturing. By precise robotic rotation of the clamp carriages 120A, 120B and vessel holders 150A, 150B, and utilizing a cable driven mechanism to achieve a small physical footprint, the rotating vessel 110A, HOB may be oriented to align with the microscope view and enable easy access for suturing for each consecutive stitch. By changing the size of the vessel holder 150A, 150B, the system can accommodate varying sizes of vessel 110A, 110B.

[0098] The smart micro-suture needle driver 162 shown in Figure 9B can accurately and robustly deploy miniature sutures (e.g., size 9-0) utilizing a roller design for needle advancement and retraction, integrated OCT imaging to track needle position, and force sensing for suture tensioning and collision detection. The micro needle driver 162 may be placed on a lightweight robot arm to execute accurate and robust suturing with a single tool.

[0099] High-resolution surgical guidance may be provided using OCT and artificial intelligence (Al) interpretation. Current standard imaging and sensing techniques are not capable of tracking vessels with the micron level precision needed for leak-free anastomosis and lack the capability to penetrate tissue to differentiate obstructions on the inside of a vessel. The system and method described herein may utilize one or more A-scan OCT fiber probes 170A, 170B placed on the robot 160 to acquire swept two-dimensional cross-sectional views of the vessels to precisely visualize and register the vessels vessel 110A, 110B to the robot 160. Machine learning (ML)-based image analysis may allow for high-fidelity interpretation of the images to accurately image and track the vessel 110A, 110B, differentiate from air, and detect obstructions from a needle driver 162 or vessel holder 150A, 150B.

[0100] The developments on microvascular manipulation, micro needle driver, and OCT guidance may be integrated into a robotic system for supervised autonomous microvascular anastomosis and performing a definitive preclinical in vivo trial in rat carotid arteries with a comparison to handsewn technique. More particularly, the design of the vascular positioning system may be miniaturized using a (e.g., nitinol) vessel holder 150A, 150B to accurately position arterial microvasculature for anastomosis. This system may be usable for both robotic and manual anastomosis procedures. The vessel holder 150A, 150B may be designed using measured radial pressure (i.e., the pressure a vessel exerts when radially expanded), and needle puncture forces (i.e., force the needle exerts on the vessel during suturing) taken from ex vivo rat carotid artery samples.

[0101] Design and Fabrication of Microvascular Holder

[0102] Figure 10 illustrates a perspective finite element analysis (FEA) image of the microvessel holder 150A, according to an embodiment. The vessel holder 150A in Figure 10 may be smaller the vessel holder 150A shown in Figure 4. For example, a diameter of the vessel holder 150A in Figure 4 may be from about 1.0 mm to about 3.0 mm or from about 3.0 mm to about 5.0 mm in the radially-collapsed state, and from about 3.0 mm to about 5.0 mm or from about 5.0 mm to about 10.0 mm in the radially-expanded state. A diameter of the vessel holder 150A in Figure 10 may be from about 0.5 mm to about 1.0 mm in the radially-collapsed state, and from about 1.0 mm to about 3.0 in the radially-expanded state.

[0103] As shown in Figure 10, the vessel holder 150A may be simulated and analyzed using finite element analysis (FEA). Once validated, the vessel holder 150 A may be fabricated using a laser cut nitinol tube heat set into an expanded position. Sheathing this holder 150A with a stainless-steel tube 140 A may collapse the tines 152 of the nitinol, allowing the vessel 110B to be loaded on the vessel holder 150A. The vessel holder 150A expands when unsheathed to grip the vessel HOB from the inside. The clamp carriage may be clamped using a small steel spring, and plastic components may be fabricated using a 3D printer capable of 25-micrometer resolution. The system may be actuated using pull wires with small-scale high-resolution encoders. The vessel holder 150A can be used for a range of vessel sizes, but larger vessel holders can be fabricated for additional vessel sizes.

[0104] Semi -Automated Tissue Orientation Controller

[0105] The MAPS 100 may improve the performance of manual anastomosis for microvasculature. The system may be configured for pre-clinical use via a passive locking arm and foot pedals. Three pedals may be incorporated into the positioning system to enable rotation clockwise, counterclockwise, and to unsheathe the vessel holders 150A. Three pedals are sufficient because rotation and sheathing of the nitinol in both holders are coupled together. The pedals may be positioned under the table to enable hands-free surgical control. The MAPS 100 may be attached to the end of a passive locking arm. This may allow the surgeon to easily position the system where it is needed in the surgical scene and twist one knob to lock it in place. Once positioned, the surgeon can load the vessels 110A, HOB into the clamps 130A, 130B and over the vessel holders 150A, 150B. Pressing the pedal may unsheathe the vessel holders 150A, 150B allowing them to expand inside the vessels 110A. HOB. While suturing, the physician can rotate the vessels 110A, 110B between suturing locations by simply pressing the corresponding pedal. When finished placing sutures, the physician may sheath the vessel holders 150A, 150B and remove the vessels 110A, 110B from over the vessel holders 150A, 150B. This allows the vessels 110A, 110B to be aligned and for the sutures to be tied off. Finally, the physician can remove the anastomosed vessel from the clamps 130 A, 13 OB.

[0106] The forces of the needle insertion and vessel on the vessel holder 150A may cause deflection. In that event, the vessel holder 150A, 150B may be changed to support the tines 152 from both ends instead of being cantilevered. This may allow the vessel holder 150A, 150B to provide substantially more radial force. If the grip force of the vessel holder 150A, 150B on the inside of the vessel 110A, 110B is insufficient to avoid slippage of the vessel 110A, 110B, surface treatments on the vessel holder 150A, 150B can be utilized to increase the friction such as sandblasting, laser etching, or dip coating.

[0107] Smart Micro-suture Needle Driver

[0108] Microvascular anastomosis for vessels 110A, 110B with outer diameter smaller than 1.0 mm (about 0.04 in) is extremely challenging, and thus suturing devices for effective and autonomous suturing is significant for safe and reliable procedures. Manual anastomosis tools and teleoperated robotic anastomosis have been tested for microvascular anastomosis with limited performances. Taking advantage of proven accuracy and repeatability for needle positioning and suture path planning, autonomous robotic anastomosis may advance the state of art. The system and method described herein may include 1) a smart microneedle tool capable to drive straight needles safely and precisely; and 2) a needle drive positioner with integrated force-sensing capabilities for suture tensioning to improve the success rate for teleoperated microvascular anastomosis.

[0109] Design and Fabrication of Microneedle Tool

[0110] Figure 11 illustrates a perspective view of the microneedle tool 162, according to an embodiment. A clipping tool with a circular needle can position a needle 1106 with good repeatability with an average holding force of 2.9 N. A compact and straight microneedle tool 162 with 9-0 suture may enable smaller vasculature (such as 1 mm) anastomosis. The tool, attached to a force sensor, may achieve positioning accuracy of +/- 0.25 mm while the suture is tensioned to 0.5 N. The microneedle tool 162 may include a needle advance head and an actuation system, as shown in Figure 11.

[OHl] The tool head may include two pairs of metal rollers 1114 embedded in a plastic case to support, guide, and advance the straight needle 1106. The needle advance force may be provided by rollers-to-needle contact friction force controlled with adjustable leaf springs. The rollers’ diameters and radial and contact forces may be estimated by finite element analysis (FEA) simulations and optimized to have the smallest possible outer diameter while still adequately supporting the needle 1106 without slipping (e.g., in presence of blood or other body fluids). The guiding rollers 1114 may be individually supported and/or rotated by vertical stainless-steel shafts 1116 actuated by DC Brushless Motors and controlled through (e.g., EPOS2) controllers. An interface with individual spring-loaded push-pins may couple the rotary motion from the motors to the tool shafts 1116. The microneedle tool may allow the suture to be tensioned to 0.5 N as measured by a 6-axis micro force-torque sensor.

[0112] Development of Needle Drive Positioner

[0113] As described above, the small vessel positioning system can perform anastomosis in 5 mm vessels with minimal human intervention. The smart needle drive positioner system may improve the success rate for teleoperated microvascular anastomosis. The needle drive positioner may integrate the microneedle tool 162 within a teleoperated robotic arm and the microvascular holder (Aim 1). The system may be used to perform anastomoses in 1 mm (or smaller) diameter vessels 110A, HOB.

[0114] Figure 12 illustrates a microvascular suturing workflow for a single 1 mm vessel 110A, according to an embodiment. The motorized microneedle tool 162 may be connected to a lightweight robot (LWR) 160 through a 6-axis micro force-torque sensor. A versatile haptic device may be used to facilitate teleoperation. The haptic device translation and rotation axes may be used to control the LWR 160, while the grasping axis may be used for controlling the microneedle tool 162. The microvascular holder (Aim 1) may be supported with a passive locking arm and controlled with a foot pedal. Real-time toolkit (RTT) components may be used for real-time control on the hardware of the needle driver positioner, including robot system and/or the microneedle tool 162. A surgical microscope may be used for visualization of the surgical field. For anastomoses experiments, the vessel 110A may be placed into the MAPS 100 and manually positioned into the microscope focal plane. The clinician may use the haptic console to control the microneedle tool position and orientation (via LWR) and to advance and stop the needle 1106. The suture tension may be measured by the force sensor and displayed in real-time. Auditory force feedback substitution or haptic feedback (e.g., from the haptic device) may be employed to limit the suturing force.

[0115] The roller’s diameter may be modified (e.g., increased) to provide a better contact force with the needle 1106. Alternatively, metal coatings may be used to increase the friction coefficient. The OCT fiber 170 may be integrated orthogonal to the needle path (Aim 3) may also provide an accurate measurement of when the needle starts and ends crossing the path of the fiber 170, enabling online adjustments of slipping.

[0116] Surgical Guidance Using OCT and Machine Learning

[0117] Currently, no intraoperative imaging devices exist that can accurately delineate vessel wall and luminal anatomy during microvascular anastomosis to accurately guide suturing procedures and assess the vessel in real time intra- and post-operatively to anticipate potential complications. OCT imaging has been studied extensively for vascular imaging, and, for larger vessels, the focus was mostly on intravascular imaging. The approach described herein lies in extravascular imaging using small OCT probes. A commonly used OCT imaging approach uses an extravascular OCT technology integrated into surgical microscopes. This technology, however, is limited to direct orthogonal scanning angles using the surgical microscope. Imaging may be limited in deep fields and is not possible around comers or in situations where direct visualization of the parent vessel is obscured. The artificial intelligence intraoperative vascular OCT imaging system (ALIVOCT) described herein offers a robot-integrated and scanned, high-resolution, real-time vessel -suturing tool tracking with vessel lumen Alevaluation that may improve vascular surgical accuracy and outcomes. The development of the ALIVOCT may improve intraoperative detection and assessment of vascular patency and offers potential further applications in a variety of surgical subspecialties.

[0118] Tissue Type and Tissue Edge Detection

[0119] The system and method described herein may implement a data-driven Al method, based on a “deep-learning” network to identify different tissue types, and detect vessel edges that may help visualize the whole layer structures of the vessel and determine the optimum suturing tool position relative to the target.

[0120] Figure 13 illustrates a schematic view of a network architecture of a feature-based multi-layer perception plus three-channel CNN for tissue type and edge detection, according to an embodiment. The tissue type and tissue edge detection may be based on an in-house custom network. A 3 channel CNN may be implanted that incorporates A-line images, attenuation coefficients, and backscattering ratios along with a feature-based multilayer perception to accurately detect tissue type and tissue edge. One or more IVOCT images (>8000) of both of in vivo and ex vivo tissues may be acquired, and an expert may help guide engineers to label different parts of the vessel. The training data size may be based upon previous work with CNN-based retinal tissue segmentation and needle tracking with a robust result. Those images obtained from the test and validation studies may be used for training the network using a highspeed GPU. The pre-trained network may be then used to segment the vessel anatomical structure from the background and identify the vessel edges.

[0121] Autonomous Tool Positioning with OCT Image Guidance

[0122] The OCT with the fiber sensor 170 can accurately detect surgical tools (e.g., needle 1106) to different layers of target tissue. The fiber optic OCT imaging/ sensing probes 170 may be integrated directly into the suturing tools controlled by robots to accurately determine the position and track the tool-tissue movements during the procedure. More particularly, two fiber optic probes 170A, 170B, one forward and another one side-viewing, may be integrated into the suturing tool tip with a known offset, as shown in Figure 9B. The fibers 170A, 170B may provide cross-sectional OCT images of the vessel 110A, HOB and the vessel holder 150A, 150B, axially and/or horizontally. An OCT positioning routine may be used, whereby the suturing tool 162 may move in a sweeping motion along the x and/or y-axes to generate high- resolution topologies of the vessel 110A, HOB. A-scan, depth-resolved OCT images may be obtained at the rate of ~10 kHz continuously so images are generated in real time. Using these images, the position of the suture tool 162 relative to the vessel 110A, 110B and the vessel holder 150A, 150B may be determined. The suture tool position can then be guided to the correct location relative to the positioning system for suture placement. This process may be repeated prior to each suture to confirm correct placement of the suturing tool 162. Figure 14 illustrates an OCT image-based tissue classification result using a feature-based network, according to an embodiment.

[0123] In an embodiment, different robot manipulation configurations may be used for/by the suture tool 162. More particularly, the suture tool 162 may be attached to a variety of robot platforms such as the UR robot arms, Kuka robot arms, the Galen robot, the Da Vinci, along with any similar platform. Additionally, between the surgical robot 160 and the suture tool 162, an additional manipulation stage may be used such as a Cartesian Stage (e.g., actuates the tool directly in x, y and z like a Cartesian 3D printer), or a Delta Parallel Stage (e.g., actuates the tool indirectly in x, y, and z like a Delta Stage 3D Printer), or a Stewart Platform.

[0124] Vessel Patency Analysis with OCT

[0125] Current intraoperative imaging of vasculature is limited to fluorescent or indocyanine green video-angiography (ICG-VA), conventional endovascular digital-subtraction angiography (DSA), and continuous-wave Doppler instruments. ICG-VA only provides information on blood flow and vessel patency in direct visualization of the surgical microscope. Intraoperative DSA, the gold standard of intraoperative imaging, is time-consuming and requires extensive preparation. In addition, although an intraoperative angiogram may show significant vessel stenosis or occlusion, the imaging lacks a cross-sectional microvascular image to display the exact location and etiology of the vessel occlusion. The system and method described herein incorporate a 3-D Doppler capability to AI-IVOCT for precise automated patency assessment. 3-D Doppler IVOCT imaging provides 3-D visualization of blood flow and can identify any turbulent flow and blockages that may require re-suturing.

[0126] The AI-IVOCT system may include three modules: (1) a swept-source OCT for robotically scanned 3-D imaging, (2) a workstation for Doppler OCT signal processing, and (3) Al-based OCT image segmentation and analysis of the vessel patency, and a 2D/3D imaging rendering/display. If difficulty is reached in assessing vessel lumen patency using the models discussed above, the vessel may be imaged at multiple angles such as 0°, 60°, and 120° to make a virtual 360° vessel reconstruction by rotating the suturing tool accordingly.

[0127] Semi -Autonomous Microvascular Anastomosis and In vivo Studies

[0128] Autonomous robots show may be used to improve clinical outcomes but have not translated to microsurgeries, where suture precision and repeatability is critical to anastomotic outcome. Combining a microvascular positioning stage (Aim 1), smart suturing tool (Aim 2), and integrating high resolution OCT image guidance (Aim 3), may achieve supervised- autonomous anastomosis of microvasculature. Using the existing surgical robot, the three independent systems developed in Aims 1-3 may be integrated into a single robotic platform as illustrated in Figures 9A-9C.

[0129] Surgical Robot Integration and Surgical Workflow for Murine Cadaver Study

[0130] The MAPS 100 (Aim 1), smart suturing tool 162 (Aim 2), and OCT image guidance 170 (Aim 3) may be integrated within the surgical robot 160 (e.g., STAR) architecture to enable supervised-autonomous microvascular anastomosis. A supervised-autonomous suturing strategy for microvascular anastomosis may be used that is based on the surgical robot system and robotic architecture. The MAPS 100 with passive arm (Aim 1), and KUKA LBR MED robot with suturing tool 162 (Aim 2), may be mounted to the patient bed and under a surgical microscope, as shown in Figures 9A-9C.

[0131] The surgeon may manually load the microvasculature on the MAPS 100, and the suturing tool 162 may be jogged into the surgical field. Using optical fiducials, a real-sense camera 180 may be used to calibrate the suturing tool 162 to the MAPS 100. This calibration step may be performed a single time. The MAPS 100 may orient the microvasculature (Aim 1), and the suture tool 162 may move to a hover position (Aim 2). The robot 160 may generate a topological image of the tissue by sweeping the OCT fiber (Aim 3) and then align the suturing tool to the MAPS 100. The surgeon can make fine adjustments to the suturing tool 162 through a user interface and verify suture placement. The robot 160 may move to the next stitch using the autonomous workflow only after the previous suture placement is verified by the surgeon using the microscope at the patient's bedside.

[0132] Figure 15A illustrates a perspective view of a cantilevered adjustable nitinol holder 150A (or 150B) in a first state, and Figure 15B illustrates the cantilevered adjustable nitinol holder 150A in a second state, according to an embodiment. The nitinol may be supported at both ends to improve radial strength. A wire may be pulled through the middle (in the direction 1500) to apply compressive force to the nitinol tines, causing them to expand radially, as shown in Figure 15B. This makes the expanded diameter adjustable, which allows for suturing a range of vessel diameters.

[0133] Figure 16 illustrates a perspective view of a notched wheel 1600 for holding ends of a suture 1620, and Figures 17 and 18 illustrate perspective views of the wheel 1600 in the MAPS 100, according to an embodiment. The wheel 1600 rotates along with the nitinol holder 150A (or 150B) and/or the rotating clamp 130A (or 130B). Like the clamp 130A, the wheel 1600 can open and close allowing the vessel 110A (or HOB) to easily be loaded through. During suturing, each suture end can be placed in the corresponding notch. After all sutures have been placed, corresponding suture ends can easily be identified for knot tying.

[0134] As used herein, the terms “inner” and “outer”; “up” and “down”; “upper” and “lower”; “upward” and “downward”; “upstream” and “downstream”; “above” and “below”; “inward” and “outward”; and other like terms as used herein refer to relative positions to one another and are not intended to denote a particular direction or spatial orientation. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.”

[0135] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the disclosure. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the systems and methods described herein. The foregoing descriptions of specific examples are presented for purposes of illustration and description. They are not intended to be exhaustive of or to limit this disclosure to the precise forms described. Many modifications and variations are possible in view of the above teachings. The examples are shown and described in order to best explain the principles of this disclosure and practical applications, to thereby enable others skilled in the art to best utilize this disclosure and various examples with various modifications as are suited to the particular use contemplated. It is intended that the scope of this disclosure be defined by the claims and their equivalents below.

Claims

Claims

1. A device configured to be used during a surgical procedure, the device comprising: a vessel holder comprising a plurality of tines that are circumferentially-offset from one another, wherein the tines of the vessel holder are configured to actuate between a radially- collapsed state and a radially-expanded state, and wherein the tines comprise nitinol.

2. The device of claim 1, further comprising a sheath configured to actuate between a first position and a second position, wherein the sheath in the first position is positioned around the tines of the vessel holder, which holds the tines of the vessel holder in the radially-collapsed state, wherein the vessel holder and the sheath are configured to be inserted into a luminal structure, and wherein the sheath in the second position is withdrawn from the tines of the vessel holder, which allows the tines of the vessel holder actuate into the radially-expanded state to hold the luminal structure open.

3. The device of claim 2, wherein the luminal structure comprises a blood vessel, a nerve, a bowel, a urethra, a ureter, or a combination thereof.

4. The device of claim 2, wherein the vessel holder is configured to rotate while in the radially-expanded state, which rotates the luminal structure.

5. The device of claim 2, wherein the tines in the radially-expanded state provide a counterforce to a force that is exerted by a needle when the needle is being inserted through the luminal structure to suture the luminal structure, wherein the needle is configured to pass through gaps between the tines, and wherein the gaps between the tines provide a consistency of spacing between sutures.

6. A microvascular anastomosis positioning system (MAPS), comprising: a first clamp carrier configured to rotate around a first axis; a first clamp coupled to the first clamp carrier, wherein the first clamp is configured to actuate between an open position and a closed position, wherein a first luminal structure is configured to be inserted into the first clamp in the open position, and wherein the first clamp is configured to hold the first luminal structure in the closed position; a first vessel holder comprising a plurality of tines that are circumferentially-offset from one another, wherein the tines of the first vessel holder are configured to actuate between a radially-collapsed state and a radially-expanded state, and wherein the first vessel holder is configured to rotate around a second axis; and a first sheath configured to actuate between a first position and a second position, wherein the first sheath in the first position is positioned around the tines of the first vessel holder, which holds the tines of the first vessel holder in the radially-collapsed state, wherein the first vessel holder and the first sheath are configured to be inserted into a second luminal structure, and wherein the first sheath in the second position is withdrawn from the tines of the first vessel holder, which allows the tines of the first vessel holder actuate into the radially- expanded state to hold the second luminal structure open.

7. The MAPS of claim 6, wherein a diameter of the first vessel holder is from about 0.5 mm to about 1.0 mm in the radially-collapsed state, and from about 1.0 mm to about 3.0 in the radially-expanded state.

8. The MAPS of claim 6, wherein a diameter of the first vessel holder is from about 1.0 mm to about 5.0 mm in the radially-collapsed state, and from about 5.0 mm to about 10.0 mm in the radially-expanded state.

9. The MAPS of claim 6, further comprising: a second clamp carrier configured to rotate around the second axis; and a second clamp coupled to the second clamp carrier, wherein the second clamp is configured to actuate between the open position and the closed position, wherein the second luminal structure is configured to be inserted into the second clamp in the open position, and wherein the second clamp is configured to hold the second luminal structure in the closed position.

10. The MAPS of claim 9, wherein the first and second clamp carriers are aligned when the first and second luminal structures are inserted into the first and second clamps, respectively, and wherein the first and second clamp carriers are misaligned when the first vessel holder and the first sheath are inserted into the second luminal structure.

11. The MAPS of claim 9, further comprising a second vessel holder comprising a plurality of tines that are circumferentially-offset from one another, wherein the tines of the second vessel holder are configured to actuate between the radially-collapsed state and the radially- expanded state, and wherein the second vessel holder is configured to rotate around the first axis.

12. The MAPS of claim 11, further comprising a second sheath configured to actuate between the first position and the second position, wherein the second sheath in the first position is positioned around the tines of the second vessel holder, which holds the tines of the second vessel holder in the radially-collapsed state, wherein the second vessel holder and the second sheath are configured to be inserted into the first luminal structure, and wherein the second sheath in the second position is withdrawn from the tines of the second vessel holder, which allows the tines of the second vessel holder actuate into the radially-expanded state to hold the first luminal structure open.

13. The MAPS of claim 11 , wherein the first clamp carrier and the second vessel holder are configured to rotate simultaneously around the first axis to rotate the first luminal structure between different suturing positions.

14. The MAPS of claim 13, wherein the second clamp carrier and the first vessel holder are configured to rotate simultaneously around the second axis to rotate the second luminal structure between the different suturing positions.

15. The MAPS of claim 14, wherein the first and second axes are parallel to one another and laterally-offset from one another.

16. A system for performing a surgical anastomosis procedure, the system comprising: a macrovascular anastomosis positioning system (MAPS), wherein the MAPS comprises: a clamp carrier configured to rotate around a first axis; a clamp coupled to and configured to rotate with the clamp carrier, wherein the clamp is configured to actuate between an open position and a closed position, wherein a first vessel is configured to be inserted into the clamp in the open position, and wherein the clamp is configured to hold the first vessel and to prevent blood flow through the first vessel in the closed position; a vessel holder comprising a plurality of tines that are circumferentially-offset from one another, wherein the tines of the vessel holder are configured to actuate between a radially-collapsed state and a radially-expanded state, and wherein the vessel holder is configured to rotate around a second axis that is parallel to and laterally-offset from the first axis; and a sheath configured to actuate between a first position and a second position, wherein the sheath in the first position is positioned around the tines of the vessel holder, which holds the tines of the vessel holder in the radially-collapsed state, wherein the vessel holder and the sheath are configured to be inserted into a second vessel, and wherein the sheath in the second position is withdrawn from the tines of the vessel holder, which allows the tines of the vessel holder actuate into the radially-expanded state to hold the second vessel open; and an imaging system configured to measure a parameter related to a position of a needle with respect to the vessel holder, the second vessel, or both.

17. The system of claim 16, further comprising a surgical robot comprising the needle that is configured to suture the first and second vessels together.

18. The system of claim 16, wherein the imaging system comprises an optical coherence tomography (OCT) system including a fiber that is aligned with the needle, and wherein the fiber is configured to measure the parameter in front of the needle and the fiber.

19. The system of claim 18, wherein the OCT system is configured to determine a presence of a plurality of different elements in front of the needle and the fiber based upon the measured parameter, and wherein the elements comprise the second vessel, the vessel holder, the second vessel over the vessel holder, and air.

20. The system of claim 19, wherein the OCT system is configured to cause the MAPS, the surgical robot, or both to move in response to the presence of the vessel holder, the second vessel over the vessel holder, or air to cause the needle to be aligned with the second vessel and positioned over a gap between the tines of the vessel holder before the surgical robot sutures the first and second vessels together.