Vein collection device

Abstract

The present invention provides a device for use in non-contact vein harvesting, including a tissue separating side branch cutting head having a tubular body having an inner and outer surface and extending between a forward end and a rear end, the forward end being adapted to separate or cut tissue surrounding a blood vessel to be harvested, a lumen defined within the inner surface and opening at the forward and rear ends and adapted to receive a portion of the blood vessel, a plurality of slots formed through the body and extending longitudinally between the open and closed ends, each adapted to receive a side branch and guide the side branch toward the closed end, a plurality of cutting devices having a pair of cutting tools associated with each slot and each adapted to cut the side branch, and a processing module. The processing module automates the device, enabling detection of the side branch between the pair of cutting tools and initiating the act of energizing the pair of cutting tools to cut the side branch without the need for visual detection, typically requiring an endoscope.

Description

[Technical Field]

[0001] The present invention relates to a blood vessel harvesting device.

[0002] Background technology Endoscopic vein harvesting (EVH) is a procedure to harvest the great saphenous vein (GSV), the most common graft used in coronary artery bypass surgery. This procedure has widely replaced more invasive open vein harvesting techniques.

[0003] In this procedure, a small incision is made and an endoscopic camera is used as a blunt dissection instrument to create a subcutaneous tunnel in the tissue below the skin. The side branches of the GSV are usually cauterized and divided by RF ablation using a separate device, typically bipolar forceps.

[0004] The problem with this technique, and the use of the associated devices, is that while it is less traumatic, it is not without trauma. Due to the punctures required for this technique, the vein is often damaged, reducing patency rates.

[0005] Furthermore, this technique requires a high level of training to enable skilled operation of an ablation device guided by endoscopic camera images, an additional piece of equipment required to use this technique.

[0006] First, given that vein grafts offer lower patency rates than arterial grafts, with evidence that patency rates improve when the vein is harvested and covered by surrounding tissue, it is important that the extraction procedure be such that it reduces damage to the vein and includes a predetermined amount of surrounding tissue.

[0007] Furthermore, with current EVH devices, the vein is separated from the surrounding tissue and side branches and then removed, at which point the vein may be subjected to shear stress due to friction between the vein surface and the surrounding tissue.

[0008] Another problem with current EVH is thermal injury, which occurs when the electrode used to cut the side branch is too close to the surface of the main vein being harvested, potentially thermally damaging the vein.

[0009] JP 2016042987 A addresses some of the aforementioned problems to some extent. This document outlines a vessel harvesting device featuring a main tissue separation head and a side branch cutting head. The cutting head includes a groove through which surrounding vessels pass during operation of the device to undergo ablation dissection.

[0010] However, a drawback of this device is that it cannot detect when a peripheral vessel has entered the groove, preventing activation of the cutting mechanism in that particular slot to cut the peripheral vessel.

[0011] In the absence of a detection mechanism, the only viable options are direct observation (which requires an endoscope, resulting in a non-minimally invasive procedure) and initiating ablation current at any perceived mechanical resistance (risking rupture of side branches) or constantly energizing all slots, potentially causing thermal damage to the surrounding tissue or the main branch of the vein. Another drawback of JP2016042987 is its reliance on straightening the vein to be harvested. This involves inserting a reinforcing section into the vein to prevent inadvertent incision by the device. Unfortunately, this pre-treatment is potentially traumatic and poses the risk of puncturing the vein.

[0012] The present invention at least partially solves these problems.

[0013] Summary of the Invention In a first aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: A tissue separating side branch cutting head, comprising: a tubular body having an inner surface and an outer surface and extending between a front end and a rear end, the front end adapted to separate or cut tissue surrounding a blood vessel to be harvested; a lumen defined within the interior surface, the lumen opening at a leading end and a trailing end, the lumen adapted to receive a portion of a blood vessel; a plurality of slots formed through the body and extending longitudinally between the open end and the closed end, each adapted to receive a side branch and direct the side branch toward the closed end; a plurality of cutting devices each having a pair of dissection tools associated with a respective slot and each adapted to cut a side branch; a processing module; A blood vessel harvesting device including a tissue separating side branch cutting head is provided, characterized in that a processing module is adapted to detect a change in an electrical characteristic between the pair of cutting instruments, and, when the change exceeds a limit indicating the presence of a side branch between the pair of cutting instruments, initiate an operation of energizing the pair of cutting instruments to cut the side branch.

[0014] The processing module may include a detector electronically connected to each pair of cutting instruments in a respective detection circuit and adapted to measure an electrical characteristic between the pair of cutting instruments when the respective detection circuit is closed by the circuit-specific switch and the first master switch.

[0015] The processing module may include a control unit adapted to sequentially close the detection circuits of each pair of cutting instruments at the circuit-specific switches to facilitate measuring the electrical characteristics, and to open the detection circuits at the circuit-specific switches if the measurements received from the detectors do not indicate the presence of a side branch.

[0016] The processing module may include an ablation generator electronically connected to each pair of cutting instruments in a respective cutting circuit and adapted to energize the pair of cutting instruments when the respective cutting circuit is closed by the circuit-specific switch and the second master switch.

[0017] The control unit may be adapted to open all detection circuits with the first master switch and close respective cutting circuits with the second master switch to energize the pair of cutting instruments when measurements received from the detectors indicate the presence of a side branch between the pair of cutting instruments.

[0018] The processing module may include an alarm activated by the control unit to issue an alarm signal when measurements received from the detector indicate the presence of a side branch between the pair of dissection instruments.

[0019] The processing module may include an actuator adapted, when activated in response to the alarm signal, to open all detection circuits with a first master switch and close respective cutting circuits with a second master switch to energize the pair of cutting instruments.

[0020] Each circuit-specific switch may comprise two switches configured to interrupt both the supply and return lines of the circuit.

[0021] Each pair of dissection instruments may be either a movable pair of dissection instruments adapted to move towards and away from each other, or a stationary pair of dissection instruments.

[0022] The movable pair of cutting instruments may include an actuator electrically interposed in a respective cutting circuit between the ablation generator and the pair of cutting instruments, which actuates and moves the pair of movable cutting instruments when the cutting circuit is energized.

[0023] The tubular body may include a semi-tubular portion defined between leading and trailing ends and first and second longitudinal edges.

[0024] Each half may be separate and adapted to engage the other along first and second longitudinal edges to form the tubular body.

[0025] The two halves may be connected along their respective first longitudinal edges such that the halves can move between an open position in which their respective second longitudinal edges are spaced apart and a closed position in which their respective second longitudinal edges come together to form the tubular body.

[0026] Each slot may be tapered or partially tapered to guide the side branch into the closed end.

[0027] The slots may be equally radially spaced around the body.

[0028] The front end can be fitted with a plurality of cutting edges, each between a pair of adjacent slots.

[0029] Each cutting device is radially spaced from the circumference of the lumen.

[0030] In a second aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: a vessel containment chain extending between a front end and a rear end and including a plurality of segments pivotally connected to one another, each adapted to contain a portion of a vessel to be harvested; A blood vessel harvesting device is provided that includes a tubular cutting head connected to the front end of the chain, the cutting head having a front end adapted to separate or cut tissue surrounding a blood vessel and a lumen adapted to receive passage of the blood vessel.

[0031] Each segment may include two semi-tubular portions that engage with one another along respective first and second longitudinal edges to form a tubular body.

[0032] The two semi-tubular portions may be pivotally connected to one another along their respective first longitudinal edges to move between an open position in which their respective second longitudinal edges separate, and a closed position in which their respective second longitudinal edges engage to form the tubular body.

[0033] Each segment may include a semicircular base element that defines a channel, and a closure that engages the semicircular element and moves between a closed position and an open position to close at least a portion of an opening to the channel.

[0034] The closure may be a pair of resiliently deformable flaps positioned on either side of the opening to resiliently open and close the opening.

[0035] Alternatively, the closure may be a pair of toggle elements located on either side of the opening that rotate from an open position to a closed position.

[0036] Alternatively, the closure may be an arcuate shutter that slidably engages the base element to move between open and closed positions.

[0037] The base element may include an arcuate slot through which the arcuate shutter moves when moved to the open position.

[0038] The shutter may have a biasing element in the slot that biases the shutter to a closed position.

[0039] The biasing element may be a concertina element or a spring loaded element.

[0040] In a third aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: extending between a forward end and a rearward end; a plurality of segments, each adapted to include a portion of a blood vessel to be harvested; a plurality of flexible connectors, each of which is interposed between adjacent pairs of segments for flexibly connecting the segments in the chain; A blood vessel harvesting device is provided that includes a blood vessel receiving chain with a front end adapted to separate or cut tissue surrounding the blood vessel and a tubular cutting head connected to the front end of the chain, the cutting head having a lumen adapted to receive passage of the blood vessel.

[0041] Each flexible connector may have a composite including a first flexible material and a second structural material.

[0042] The first material may be a flexible material and the second material may be less flexible than the first material and is included to prevent excessive bending of the connector.

[0043] The composite may include alternating layers of a first material and a second material.

[0044] Alternatively, the composite may comprise a helical interengagement of a first material with a second material, preferably the second material being a helically arranged seam embedded within the first material.

[0045] The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0046] [Figure 1] 1 is a perspective view of a tissue separation side branch cutting head (hereinafter referred to as cutting head) for a blood vessel harvesting device according to a first embodiment of a first aspect of the present invention. FIG. [Figure 2] FIG. 2 is a longitudinal cross-sectional view of the cutting head of FIG. 1. [Figure 3] 1 is a longitudinal cross-sectional view of a blood vessel harvesting device according to a second embodiment of the first aspect of the present invention; FIG. [Figure 4] FIG. 2 is a plan view of the cutting head of FIG. 1. [Figure 5] 10A and 10B show diagrammatically slots in a cutting head; [Figure 6A] 5 shows a schematic view of a portion of the slot of FIG. 4 showing a cutting device; [Figure 6B] 5 shows a schematic view of a portion of the slot of FIG. 4 showing a cutting device; [Figure 7] FIG. 10 is a perspective view of a blood vessel harvesting device according to a third embodiment of the first aspect of the present invention. [Figure 8] FIG. 10 is an exploded perspective view of a blood vessel harvesting device according to a fourth embodiment of the first aspect of the present invention. [Figure 9]FIG. 3 is a circuit diagram illustrating a method for supplying power and controlling each cutting device. [Figure 10A] A process flow diagram is provided detailing how the cutting device is powered and controlled to perform the cutting function of the cutting device. [Figure 10B] A process flow diagram is provided detailing how the cutting device is powered and controlled to perform the cutting function of the cutting device. [Figure 11] 1 shows diagrammatically a vessel harvesting device according to a second embodiment of the present invention, comprising a vessel harvesting device and a chain comprising a plurality of interconnected vessel-containing segments; [Figure 12A] 12 is a diagrammatic representation of the vessel harvesting device of FIG. 11 deployed during vessel harvesting; [Figure 12B] 12 is a diagrammatic representation of the vessel harvesting device of FIG. 11 deployed during vessel harvesting; [Figure 13A] 11 is an isometric view of a vessel receiving segment (hereinafter referred to as segment) of the vessel harvesting device of FIG. 10 in a closed configuration. [Figure 13B] 11 is an isometric view of a vessel receiving segment (hereinafter referred to as segment) of the vessel harvesting device of FIG. 10 in an open configuration. [Figure 14] 10 shows isometric views of segments according to a second embodiment of the second aspect of the present invention; [Figure 15] 10 shows isometric views of segments according to a third embodiment of the second aspect of the present invention; [Figure 16] 10 shows isometric views of segments according to a fourth embodiment of the second aspect of the present invention; [Figure 17] 10 shows isometric views of segments according to a fifth embodiment of the second aspect of the present invention; [Figure 18A] 10 shows an isometric view of an open configuration of a segment according to a sixth embodiment of the second aspect of the present invention; [Figure 18B] 10 shows an isometric view of a closed configuration of a segment according to a sixth embodiment of the second aspect of the present invention; [Figure 19]1 shows an isometric view of a vessel harvesting device according to a third embodiment of the present invention, including a vessel harvesting device and a chain including a plurality of vessel-containing segments interconnected by moveable joints. [Figure 20] 1 shows an isometric view of a vessel harvesting device according to a second embodiment of a third aspect of the present invention, including a vessel harvesting device and a chain including a plurality of vessel-receiving segments interconnected with a plurality of flexible joints. [Figure 21] 1 shows an isometric view of a vessel harvesting device according to a second embodiment of a third aspect of the present invention, including a vessel harvesting device and a chain including a plurality of vessel-receiving segments interconnected with a plurality of flexible joints. [Figure 22] 1 shows an isometric view of a first embodiment of a flexible joint of a vessel harvesting device. [Figure 23] 12 is an isometric view of a second embodiment of a flexible joint of a vessel harvesting device.

[0047] MODE FOR CARRYING OUT THE INVENTION Figure 11 shows a blood vessel harvesting device 10.1 according to one embodiment of the present invention. Device 10.1 is adapted to harvest a blood vessel, preferably a vein, such as the greater saphenous vein, for use in coronary artery bypass surgery.

[0048] The device (either embodiment 10.1, 10.2...10.3) comprises a leading tissue-separating side branch cutting head 12 and a flexible trailing articulating array 14. The array consists of a plurality of vessel receiving elements designated 16.1, 16.2, 16.3...16.N. Further details regarding the device are provided below, with an initial emphasis on the first aspect of the invention, the cutting head.

[0049] 1 and 2 show a first embodiment of a cutting head 12.1. The cutting head includes a tubular body 18 extending between a front end 22 and a rear end 24, the tubular body having a conical portion 18.1 and a tubular portion 18.2, and a tubular wall 20 defined between an inner surface 20.1 and an outer surface 20.2.

[0050] A lumen 26 extends through the cutting head's tubular body 18 defined within the inner surface 20.1 and opens at both the forward and rearward ends (22, 24).

[0051] The cutting head 12.1 includes a plurality of slots (respectively designated 28.1, 28.2, 28.3...28.N) formed through the wall 20. Each slot extends longitudinally between a forward open end 32 and a closed (or base) end 34. Each slot has a respective cutting device at or toward the closed end 30 (see FIG. 5).

[0052] The slots (28.1, 28.2, ... 28.N) create between them a number of teeth (respectively designated 36.1, 36.2, 36.3 ... 36.N), the outermost edges of which define the leading edge 22.

[0053] The leading end is a cutting edge or separating edge 38, which is adapted to separate or cut the fatty tissue surrounding the blood vessel 40 to be harvested. The cutting edge can be adapted to cut the fatty tissue but retain a core of this tissue around the blood vessel by orienting the adjacent inner surface 20.1 at an angle relative to the adjacent outer surface 20.2, as shown in Figures 1, 2, and 4. Alternatively, the cutting edge can be adapted to separate the fatty tissue surrounding the blood vessel by orienting the adjacent outer surface 20.2 at an angle relative to the adjacent inner surface 20.1, Figure 3 illustrates this embodiment. Another alternative is to bevel both sides and position the cutting edge circumferentially in the center of the wall.

[0054] In a third embodiment, shown in Figure 7, the cutting head 12.3 differs from the previous embodiments in that the body 18 is not flared but remains cylindrically tubular with a cylindrically tubular lumen. In this non-limiting example, the cutting head 12.3 has four slots (18.1, 18.2, 18.3, 18.4) and four teeth (36.1, 36.2, 36.3, 36.4). The cutting device 30 includes a pair of bipolar dissectors or forceps (64.1, 64.2).

[0055] Embodiment 12.4 (see FIG. 8) differs from the previous embodiments of the cutting head in that the teeth 36.1, 36.2, ..., 36.N are of a more pointed shape with narrower, sharper and less flat separating edges 38.

[0056] The body 18 of the cutting head 12.4 includes semi-tubular sections 42.1 and 42.2 (see FIG. 8). Each half has a first longitudinal edge 44 and a second longitudinal edge 46. The halves are joined along their respective first edges around a hinge 48. This configuration allows the semi-tubular sections to pivot between an open position in which the respective second longitudinal edges 46 are spaced apart and a closed position in which the second edges 46 are engaged to assume a tubular configuration. Opposing second longitudinal edges 46 have complementary locking formations (49.1, 49.2) that interengage in a snap lock when the semi-tubular sections are moved to the closed position.

[0057] Each of the multiple vessel receiving elements (16.1, 16.2, 16.3...) of the articulating array, in one embodiment (designated 16A and shown in Figures 13A and 13B), includes arcuate halves 42.1 and 42.2 that, like head 12, are hinged to one another in the same manner as described with respect to cutting head 12 for movement between open and closed positions. Figures 13A and 13B illustrate this movement necessary to allow for enclosure of the vessel being harvested.

[0058] The vessel receiving element may appear in many embodiments, and in describing these embodiments, like features will have like names and, for ease of description, only differences from other embodiments will be described.

[0059] 14 depicts a second embodiment of vessel receiving element 16B. Arcuate halves 42.1 and 42.2 are hingedly connected along edge 44. These edges 46 feature corresponding female and male locking formations (49.1, 49.2) that resiliently interlock and securely snap together when the halves are brought into the closed position.

[0060] A third embodiment of element 16 is shown in FIG. 15. This embodiment differs from the previous embodiments in that it includes a semicircular rigid base portion 42.1 and a closure 42.2, rather than two halves. The base portion features a channel 26 and an opening 50 between its ends 51. The closure 42.2 is connected to the base portion and spans the opening. In this variation, the closure includes a pair of elastically deformable flaps (53.1, 53.2) connected to each end of the base portion and extending into the opening, effectively sealing it. However, these flaps are flexible enough to deform inward, allowing the vein to pass through the channel.

[0061] A fourth embodiment 16D, shown in Figure 16, has a pair of toggle elements (53.1, 53.2) instead of a pair of flaps that can be rotated between an open position (not shown) in which the elements do not extend substantially across the opening 50, and a closed position (shown) in which the elements extend across the opening in a partially closed state necessary to hold the received vein.

[0062] Figure 17 shows a sixth element embodiment 16E. The closure is an arcuate shutter 42.2 with a base portion 42.1 formed with a complementary arcuate slot 55 through which the shutter can slide between open and closed positions. The closed position is shown.

[0063] Spring-loaded variations of the sixth embodiment are shown in Figures 16F and 16G, which represent the seventh and eighth embodiments. In these versions, the arcuate shutter 42.2 incorporates biasing elements positioned along the inner edge of the shutter, specifically, spring-loaded curved element 57.1 and concertina element 57.2. These elements engage the ends of the slots and provide a bias to maintain the shutter in the closed position. This design ensures that the opening is consistently closed and effectively contains the vein.

[0064] For articulation of the vessel harvesting device 10 along the winding path of the harvested vein, it is essential that the elements be pivotally or flexibly interconnected. In one embodiment shown in FIG. 19 and designated 10.2, the connections between the elements and between the cutting head and the elements are facilitated by ball-and-socket joints (designated 52.1 and 52.2, respectively). This joint allows the elements to move multiaxially relative to one another, accommodating the necessary variability in the orientation of the device's longitudinal axis.

[0065] In another embodiment depicted at 10.3 in Figures 20 and 21, the vessel harvesting device includes a plurality of connectors (designated 59.1, 59.2, .....59.N), each of which is inserted between adjacent pairs of vessel receiving elements (16.1, 16.2, 16.3) to provide a continuous, interconnected, articulated row that provides the necessary flexibility.

[0066] Each connector (59.1, 59.2, .... 59.N) exhibits a semicircular body 61 that mirrors the configuration of the base portion 42.1 of the adjacent vessel receiving element and seamlessly extends and aligns with the channel 26. In one embodiment of connector 59A, the body is made of a layered composite material comprising layers of flexible material 63 alternating with layers of non-flexible material 65. This feature is best seen in FIG. 22.

[0067] In an alternative embodiment, represented as 59B in FIG. 23, the semicircular body is made from a composite material exhibiting a helical configuration. In this example, a less flexible structural material 65 forms a helical seam integrated within the flexible material 63. The seam runs continuously from end to end, connecting the bases of adjacent vessel receiving elements (16.1, 16.2). This helical seam acts like a spring, ensuring the connector remains straight and preventing excessive bending.

[0068] In use of the vessel harvesting device (10.1, 10.2, or 10.3), the surgeon first incises the leg tissue, for example if a GSV is to be harvested, to access the vein 40 and expose a segment of the vein several centimeters in length. At the entrance end 54 of the incision (see FIG. 12A), in the open configuration, the cutting head is then placed under a portion of the exposed vein, after which the two halves (42.1, 42.2) are closed around and enclose a portion of the vein 40, as shown in FIGS. 13A and 13B.

[0069] The diameter (D) of the cutting head (and of each of the vessel receiving elements 16) can be significantly larger than the diameter (d) of the vein to provide for the passage of a retained cylindrical sheath of fat / connective tissue surrounding the vein after the tissue has been cut by the cutting edge 38 of the cutting head 12.

[0070] The surgeon may then advance the cutting head beneath the skin, as shown in Figures 12A and 12B. During this process, the cutting head's leading cutting edge 38 incises or separates the tissue. In this particular scenario, as previously described, a portion of the vein is preserved within the cylindrical mass of tissue. By enclosing the vein within the cutting head, the vein acts as a guide element.

[0071] The flexible trailing articulated chain 14 feature allows the device 10 to follow the tortuous path of the vein. Unlike alternative solutions, such as those in JP 2016042987, which address this issue by straightening the vein using a straight rod placed inside the vein itself, the articulated chain approach has proven advantageous. These alternative methods are potentially more traumatic to the vein and require access to the lumen of the vein, increasing the risk of potential blood loss, a non-dry surgical field, and potential infection.

[0072] Encapsulating the vein 40 within the device significantly reduces or eliminates friction between the dissected vein and adjacent tissue. This reduced friction helps minimize potentially harmful shear stresses encountered during vein removal. Enclosing the vein 40 within a cylindrical tissue sheath improves vein graft patency rates. By protecting the surrounding tissue layers, known as "no-touch harvesting," and thereby maintaining the structural and functional integrity of the harvested vein, better outcomes and higher patency rates in coronary artery bypass surgery have been scientifically observed compared to traditional harvesting methods.

[0073] Furthermore, in order to be completely enclosed within the cylindrical lumen of the device (10.1, 10.2, 10.3), the vein would otherwise need to be severed at one end prior to insertion, which would require distension of the vein and the attendant risk of trauma due to over-distension, the risk of accidental dissection of the vein due to under-distension and the resulting sliding of the vein into the side branch incision slot 22, and the risk of blood loss and infection.

[0074] As the cutting head 12 is pushed forward to disappear under the skin, the first vessel receiving element 16.1 (of any of the previous embodiments) in the row closes around its respective portion of the vein in the manner described above. The surgeon continues to push it forward, and this sequence is repeated for each subsequent element (16.2, 16.3...16.N) until the complete portion of the vein intended to be harvested is received within the device 10.1 (see FIG. 12B).

[0075] It is contemplated within the scope of the present invention that additional vessel receiving elements may be connected to the ends of the existing articulating train 14 as needed, depending on the required length of the vein 40. The ball and socket embodiment shown in Figure 19 assists in this process, with the ball 52.1 of each additional element being pressed into the socket 52.2 of the last element in the chain.

[0076] Finally, from the opposite exit end 56, the surgeon makes an incision to expose the cutting head 12. The vein is now ready to be severed and ligated at each end (57.1, 57.2), and the device 10 is pulled from the body to remove the device and the encapsulated vein graft segment.

[0077] The vein 40 has numerous side branches 58 extending laterally from the main vein. In order for the cutting head to proceed with cutting the tissue surrounding the vein 40, these side branches must be severed to stop the blood flow.

[0078] The cutting head 12 accomplishes this by deflecting any side branches 58 it encounters away from the cutting edge 38 as the head moves forward into the adjacent slot 28. Within the slot, the peripheral vein is directed by a tapered edge 62 into the lower cutting region 60 of the slot. This region 60 terminates in a closed end 34 and houses the respective cutting device 30.

[0079] 6A and 6B, the cutting device 30 includes a pair of electrodes or dissectors (these terms are used interchangeably) designated 64.1 and 64.2. The vein is directed and positioned between these electrodes, which in this example are movable and form a pair of bipolar forceps. The bipolar forceps function as the mechanical element within the cutting device 30 and incorporate a magnetic or electromagnetic actuator 92 for electrode movement.

[0080] As described below, the cutting tools 64 can be activated automatically or by the device operator to close together, pinch the vein, and energize it (as shown in FIG. 6B). When the electrodes are energized, electrical energy passes between them, generating heat that severs side branches and stops blood flow.

[0081] Alternatively, a pair of electrodes (64.1, 64.2) may be stationary and set on either side of the slot, as shown in Figure 7. In this alternative, actuation serves only to energize the electrodes.

[0082] The energy source 82 supplies alternating current (AC) electrical energy oscillating at high frequency (RF energy). This electrical energy is converted to thermal energy as it travels through the blood vessel via the electrodes 64. The generated heat serves the purpose of cutting and sealing the blood vessel. Continuous application of RF energy should be avoided to prevent potential thermal damage to the main vein or surrounding tissue due to heat conduction. Therefore, it becomes essential to identify both when and where RF energy is needed. In the context of the present invention, it is only necessary if a side branch is detected within one of the incision slots.

[0083] To prevent thermal damage to the vein 40, the cutting device 30 is positioned a distance X from the periphery of the lumen containing the vein, as shown in Figure 4. This distance is achieved by the specific configuration of the tubular body 18 in this embodiment. Specifically, the cutting device is located in the conical portion 18.1, which is located radially outward from the cylindrical portion 18.2, as shown in the earlier embodiment of the cutting head 12.1 (Figures 1-3). Alternatively, in the embodiment shown in Figure 7, having a cylindrical body, the cutting device faces outward, radially spaced from the inner surface within the cylindrical lumen.

[0084] The use of movable electrodes offers distinct advantages, as they allow for a more focused delivery of electrical energy by bringing the electrodes together and constricting side branches. This targeted localization results in a reduction in the overall energy required, thereby minimizing the risk of thermal damage to the vein and surrounding tissue. Furthermore, the ablation process to stop blood flow within the vessel becomes more efficient, reducing the likelihood of hematomas. This is particularly important considering the routine administration of anticoagulants during bypass surgery.

[0085] To prevent the need for continuous application of RF energy and to energize the electrodes only when a side branch is present in the slot, the vessel harvesting device 10 includes a processing module 72 (FIG. 9) that is adapted to electronically communicate with each cutting device 30 to detect changes in the electrical characteristics between a pair of electrodes (64.1, 64.2) and to initiate actions leading to the severing of the side branch if the changes exceed a limit indicative of the presence of a side branch between the electrode pair.

[0086] The preferred electrical property is impedance, but may alternatively be resistance, capacitance, voltage, current, or conductivity. The selection of this property is based on the inherent impedance characteristics exhibited by various tissues. Blood vessels, especially when filled with blood, exhibit significantly different impedance levels compared to connective tissue.

[0087] In this example, processing module 72 includes a control unit 74, a detector 76, a radio frequency (RF) generator 78, and a power distribution module 80 electrically connected to a power source 82. Power distribution module 80 may be any electrical circuit or component that adapts or adjusts parameters from a power outlet to supply further components within the processing module, and may be a voltage regulator, a transformer, or a power adapter.

[0088] An alarm 83, either visual or audible, and a hand or foot operated lancing activation button 84 complete the processing module. All of these components are electronically connected to the control unit 74.

[0089] Figure 20 shows the blood collection device 10.3 with processing module 72 and the accessory nature of alarm 83 and button 84 connected to flexible trailing articulating column 14. Conductive wiring passes through the column (not shown) and terminates at the cutting device electrode pairs (64A, 64B, 64C...) in cutting head 12.3.

[0090] The RF generator 78 can be any electrical circuit that converts an electrical input signal into a high frequency and high voltage output signal. The RF generator can include a signal generator, an amplifier, a frequency tuning circuit, or a voltage conversion circuit.

[0091] The detector 76 can be any electrical circuit or component that detects side branches by measuring the impedance, voltage change, and / or current of the tissue within the electrode pair. The detector can include an impedance analyzer, an LCR circuit, an LCR meter, a Wheatstone bridge, a voltage measurement circuit, or a current measurement circuit.

[0092] The control unit 74 may include a control unit (MCU), a microprocessor, or a system on a chip (SoC). The control unit is electronically connected to the detector 76, the RF generator 78, the power distribution (80), and each electrode pair (64A, 64B, 64C) and controls the activation and deactivation of each of these components.

[0093] Each pair of electrodes (designated 64A, 64B, 64C) is connected to detector 76 in a respective detection circuit. Each detection circuit is closed by a respective circuit-specific switch 86 (shown as 86 on the detection circuit including electrode pair 64C for ease of illustration only) and a first master switch 88.

[0094] Each electrode pair is also connected in a respective lancing circuit to an RF generator 78. Each lancing circuit is closed by a circuit-specific switch 86 and a second master switch 90.

[0095] Each circuit-specific switch 86 preferably comprises a pair of switches (86.1, 86.2), each associated with a pair of electrodes, which interrupts both the "supply" and "return" lines. This configuration is advantageous because if only the supply lines are interrupted without affecting the return lines, there is a risk of current flow through all return lines of an electrode pair (and vice versa for the supply lines). In simpler terms, if the electrodes share the same medium, there is a possibility of current exchange between pairs.

[0096] The switch can be either a transistor (e.g., a MOSFET), a relay (e.g., a solid-state relay), a digital logic gate, a TRIAC, a thyristor, a solid-state switch, a programmable logic component, or an electromagnetic switch.

[0097] Following the sequence shown in FIG. 10A, the detector and control unit systematically check each electrode pair for the presence or absence of a side branch. Starting with electrode pair 64A, for example, the control unit closes circuit-specific switch 86 to activate the corresponding detection circuit. The detector measures the impedance between the electrodes, and if there is no discernible change indicating the presence of a side branch, the control unit opens the detection circuit. Subsequently, with the circuit-specific switch controlled by the control unit, the detection circuit including electrode pair 64B is engaged. This process is repeated until a side branch is identified. Throughout this successive detection cycle, the first master switch 88 remains closed.

[0098] Upon detecting a side branch, such as between electrode pair 64B, the control unit disables all detection circuits by opening first master switch 88 and activates the cutting circuit by closing second master switch 90. Since only this circuit-specific switch remains in the closed position from the previous detection cycle, the only energized cutting circuit is the one containing electrode pair 64B. All other circuit-specific switches are in the open position.

[0099] The electrodes are energized and heat generated, cutting off the side branches and stopping the bleeding.

[0100] As an alternative sequence shown in FIG. 10B, instead of automatically deactivating the detection circuit by opening the first master switch 88 and activating the dissection circuit by closing the second master switch 90, operator-controlled intervention is provided.

[0101] Upon detecting a side branch, the control unit triggers an alarm and generates an audible or visual signal. This signal serves as feedback to alert the operator to the presence of the side branch, prompting the operator to press a button. This action opens the first master switch 88, disabling the detection circuit, and closes the second master switch, activating the cutting circuit. The result mirrors the initial sequence, with the electrodes energized, generating heat and resulting in the severing of the side branch located between electrode pair 64B, according to the example.

[0102] So configured, the devices of the present invention (10.1, 10.2, 10.3) have a distinct advantage over existing minimally invasive vein harvesting devices on the market: unlike their counterparts, the devices of the present invention eliminate the need for an endoscope, as the design inherently allows the operator to determine the presence of side branches within the dedicated RF dissection element without additional visual aid.

Claims

1. A tissue separating side branch cutting head (12), a tubular body (18) having an inner surface (20.1) and an outer surface (20.2) and extending between a front end (22) and a rear end (24), said front end adapted to separate or cut tissue surrounding a blood vessel (40) to be harvested; a lumen (26) defined within said interior surface, open at said leading end and said trailing end, and adapted to receive a portion of said blood vessel; a plurality of slots (28) formed through the body and extending longitudinally between the open end (32) and the closed end (34), each adapted to receive a side branch (58) and direct the side branch toward the closed end; a plurality of cutting devices (30) each having a pair of dissection tools associated with a respective slot and each adapted to cut said side branches; a processing module (72); The processing module is adapted to detect a change in an electrical characteristic between the pair of cutting tools and, when the change exceeds a limit indicative of the presence of a side branch between the pair of cutting tools, initiate an operation to energize the pair of cutting tools to sever the side branch.

2. 2. The blood vessel harvesting device of claim 1, wherein the processing module includes a detector (76) electronically connected to each pair of lancing tools in a respective detection circuit and adapted to measure the electrical characteristic between the pair of lancing tools when the respective detection circuit is closed by a circuit-specific switch and a first master switch.

3. 3. The blood vessel harvesting device of claim 2, wherein the processing module includes a control unit (74) adapted to sequentially close the detection circuits of each pair of lancing instruments at the circuit-specific switches to facilitate the measurement of the electrical characteristic, and to open the detection circuits at the circuit-specific switches if the measurements received from the detectors do not indicate the presence of a side branch.

4. 4. The blood vessel harvesting device of claim 2 or 3, wherein the processing module includes an ablation generator (78) electronically connected to each pair of cutting instruments in a respective cutting circuit and adapted to energize the pair of cutting instruments when the respective cutting circuit is closed by the circuit-specific switch and a second master switch.

5. 5. The blood vessel harvesting device of claim 4, wherein the control unit is adapted to open all detection circuits with the first master switch and close the respective cutting circuits with the second master switch to energize the pair of cutting instruments when the measurements received from the detectors indicate the presence of a side branch between the pair of cutting instruments.

6. 5. The vessel harvesting device of claim 4, wherein the processing module includes an alarm (82) activated by the control unit to issue an alarm signal when the measurements received from the detector indicate the presence of a side branch between a pair of dissection instruments.

7. 7. The blood vessel harvesting device of claim 6, wherein the processing module includes an actuator (84) adapted, when activated in response to an alarm signal, to open all detection circuits with the first master switch and close the respective lancing circuits with the second master switch to energize the pair of lancing instruments.

8. A blood vessel harvesting device according to any one of claims 2 to 8, wherein each circuit specific switch comprises two switches configured to interrupt both the supply line and the return line of the circuit.

9. 9. The blood vessel harvesting device of claim 1, wherein each pair of dissection instruments is either a movable pair of dissection instruments adapted to move towards and away from each other, or a stationary pair of dissection instruments.

10. 10. The blood vessel harvesting device of claim 9, wherein the movable pair of cutting instruments includes an actuator (86) electrically interposed in the respective cutting circuits between the ablation generator and the pair of cutting instruments, the actuator (86) actuating and moving the pair of movable cutting instruments when the cutting circuits are energized.

11. 11. The blood vessel harvesting device of claim 1, wherein the tubular body (18) includes a semi-tubular portion (42.1, 42.2) defined between the front and rear ends and first and second longitudinal edges (44, 46).

12. 12. The blood vessel harvesting device of claim 11, wherein each half (42.1, 42.2) is separate and adapted to engage the other along the first and second longitudinal edges to form the tubular body (18).

13. 11. The blood vessel harvesting device of claim 10, wherein the two halves (42.1, 42.2) are connected along their respective first longitudinal edges (44) such that the halves can move between an open position in which the respective second longitudinal edges (46) are spaced apart and a closed position in which the respective second longitudinal edges (46) come together to form the tubular body (18).

14. A vessel harvesting device according to any one of claims 1 to 13, wherein each slot (28) is tapered or partially tapered to guide the side branch into the closed end.

15. A vessel harvesting device according to any preceding claim, wherein the slots (28) are equally radially spaced around the body.

16. A vessel harvesting device according to any one of claims 1 to 15, wherein the front end is fitted with a plurality of cutting edges (38), each cutting edge being between a pair of adjacent slots.

17. The blood vessel harvesting device of any preceding claim, wherein each cutting device is radially spaced from the circumference of the lumen.

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