Cutting assembly with irrigation and aspiration capabilities

Abstract

A cutting assembly includes an inner tube rotatably disposed within an outer tube and defining an aspiration pathway. The inner tube can include segments, which can define a flexible region associated with a curved portion of the outer tube. The outer tube can define an irrigation channel and further define an irrigation opening disposed near the cutting window or distal to the flexible region. The irrigation channel fluidly separates the aspiration lumen from the irrigation pathway to prevent irrigation fluid from flowing into the aspiration lumen through slots defined by the segments. An inner jacket can be coaxially disposed within the inner tube and configured to provide a seal between the aspiration pathway and the irrigation pathway. A distal end of the inner jacket can be disposed within the enlarged diameter portion, and a proximal end of the inner jacket can be adjacent to the inner tube.

Description

[Technical Field]

[0001] Priority claims This application claims priority to and the full benefit of U.S. Provisional Application No. 63 / 124,207, filed December 11, 2020, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Angled cutting instruments for surgical procedures facilitate treatment of anatomy that is inaccessible with straight instrumentation. Angled cutting instruments typically include an inner tube rotatably disposed within a drive shaft, or outer tube, and require torque transmission along or around curves. Angled shavers can often provide suction through an aspiration lumen defined by the inner tube. However, the geometry often required to facilitate torque transmission around curves makes the aspiration lumen susceptible to unwanted fluid inflow or outflow through the geometry. One such cutting instrument is the angled shaver described in U.S. Pat. No. 8,623,266 to Adams, in which a heat-shrink sleeve is disposed over a continuous spiral cut in the inner tube. This heat-shrink sleeve is susceptible to wear when rotated at high speeds in a journal bearing configuration along with the outer tube. Another known angled shaver is described in U.S. Pat. No. 5,922,003 to Anctil et al., in which a portion of the inner tube is replaced with a fixed-length flexible joint. Unfortunately, this construction requires complex manufacturing procedures to effectively overmold the flexible joints at the lap joints of adjacent components. Furthermore, the capacity of flexible joints to effectively transmit the torque required for certain cutting operations is questionable. Furthermore, certain flexible joints sometimes have a tendency to kink when bent, or, while well-studied, these flexible joints are typically too large for most desirable surgical applications. Therefore, there is a need in the art for an improved cutting assembly that provides irrigation and aspiration as well as torque transmission around bends. Summary of the Invention

[0003] The cutting assembly may include an aspiration pathway for aspirating excised tissue and other surgical debris, and an irrigation pathway for irrigating the surgical site. A movable or rotatable inner tube may define at least a portion of the aspiration pathway, and the irrigation pathway may be external to the inner tube. The cutting assembly includes a means for preventing fluid from within the irrigation pathway from entering the aspiration pathway, thereby maximizing irrigation and suction capabilities. The cutting assembly may include a straight or angled tube assembly. The means for preventing fluid entry may be particularly appropriate for angled cutting assemblies. The cutting assembly may be a shaver, burr, or other tissue manipulation device incorporating suction and irrigation. Alternatively, the means for preventing fluid entry may be equally applicable to instruments with irrigation but not suction, or instruments with suction but not irrigation.

[0004] The cutting assembly includes a housing hub, and a tube assembly is coupled to the housing hub. The tube assembly includes at least an outer tube, and an inner tube is movably or rotatably disposed within the outer tube. A drive hub is rigidly coupled to the inner tube and includes a key and other features configured to releasably engage a motor and a complementary component of the main instrument. The drive hub and inner tube can define an aspiration lumen in fluid communication with a cutting tip disposed at the distal end of the tube assembly. The aspiration lumen can define an aspiration path. Resected tissue and other debris, as well as fluids, are withdrawn through the cutting tip. In certain implementations, material aspirated through the inner tube passes through a curved portion of the tube assembly and passes through the housing hub for collection via the main instrument. The housing hub defines an irrigation cavity or lumen. A seal can be coupled to the housing hub and defines an opening in fluid communication with the irrigation cavity. The seal is configured to be disposed in sealing relation with a complementary feature of the main instrument to prevent fluid from escaping during irrigation delivered through the surgical instrument. The tube assembly extends distally from the housing hub. The outer tube can be rigidly coupled to the housing hub. The inner tube can rotate within the outer tube and, therefore, relative to the housing hub. When the drive hub of the cutting assembly is coupled to the main instrument, relative axial movement between the inner and outer tubes is prevented.

[0005] In certain implementations, the cutting tip defines a cutting window such that the cutting assembly is a shaver. The cutting assembly can include an outer tip portion and an inner tip portion. The outer tip portion is rigidly coupled to the outer tube. The outer tip portion includes a collar configured to be welded to the outer tube. Distal to the outer diameter of the collar, the outer tip portion can include a thinned region. The thinned region has an outer diameter smaller than the outer diameter of the collar. The thinned region can be formed by plunge grinding or other suitable manufacturing techniques. The thinned region can be tapered, for example, in a direction toward the outer window defined by the outer tip portion.

[0006] The cutting teeth can be positioned adjacent to the outer window. The inner tip portion is rigidly coupled to the inner tube. The inner tip portion defines an inner window, and the cutting teeth can be positioned adjacent to the inner window. An element can be positioned within the inner tip portion to minimize clogging of the cutting assembly. A gap can be defined between the outer tip portion and the inner tip portion. The gap provides clearance for rotation of the inner tip portion within the outer tip portion as well as clearance for drainage of irrigation from the cutting assembly at the surgical site. Fluid can be directed through the gap and can drain around the outer window.

[0007] The curved portion of the tube assembly can include a curved portion of the outer tube and a flexible region of the inner tube. The outer tube can be rigid or malleable. Another tube can be coaxially positioned outside the outer tube to provide a structure that provides rotation of the cutting window regardless of the curve of the tube assembly. The flexible region can define a slot. In one example, the flexible region includes segments interlocked to define the slot. These segments can be castellated as shown, although other interlocking geometries are contemplated. The segments can be present throughout the inner tube or can be present on at least a portion of the inner tube that includes the flexible region. Alternatively, the inner tube can include a helix, T-slot, winding, braid, or the like to transmit torque around the curve.

[0008] In certain implementations, the outer tube defines an irrigation channel extending longitudinally along its length. This irrigation channel is in fluid communication with the irrigation cavity of the housing hub. The irrigation channel can be defined by the outer tube itself. The outer tube can be a unitary structure encapsulating the irrigation channel. Alternatively, the outer tube can define a longitudinal slot or recess, or a hypotube or intermediate tube can be secured within the outer tube to define the irrigation channel. This structure provides an irrigation channel that defines an irrigation path that is fluidly isolated from the aspiration lumen. Irrigation fluid passes through the bend toward the gap without risk of unwanted entrainment into the aspiration lumen through the slot between the segments. Any number of irrigation channels is contemplated, and the irrigation channels can be arranged in any suitable radial configuration.

[0009] The outer tube further defines irrigation openings that provide fluid communication between the irrigation channel and the gap defined between the inner and outer tip portions. The irrigation openings may be slots defined by the inner surface of the outer tube. The irrigation openings may be formed by the inner thickness of the outer tube, where the irrigation channel terminates to effectively open into the gap. Any number of irrigation openings are contemplated, and the irrigation openings may be arranged in any suitable radial configuration. The irrigation openings may be located distal to the bend. The irrigation openings may be located distal to the most distal of the plurality of segments. The irrigation channels may be located near or adjacent to the inner and outer tip portions. The irrigation openings redirect fluid from the irrigation channel to the gap distal to the bend, while remaining near the cutting tip. Irrigation fluid is discharged from the cutting assembly through the cutting tip.

[0010] Fluid communication is established between the irrigation channel and the irrigation cavity of the housing hub. The housing hub can define an irrigation opening through which the inner tube extends. The housing hub can further define a recess extending from the irrigation opening in rotational alignment with the irrigation channel. This structure provides irrigation fluid flowing into the irrigation cavity of the housing hub, which is further directed through the irrigation channel. In alternative implementations, the recesses and / or irrigation channels can provide fluid communication in any rotational alignment. There may be five or more recesses, and / or the recesses and irrigation channels can subtend a larger arc such that at least a portion of one of the multiple irrigation channels is in fluid communication with at least a portion of one of the multiple recesses in any rotational orientation between the tubing assembly and / or housing hub.

[0011] In certain implementations, the tubing assembly includes an inner jacket coaxially disposed within the inner tube. The inner jacket can have an outer diameter approximately the same as the inner diameter of the inner tube. The inner jacket can be considered a sleeve or liner. The inner jacket has mechanical properties configured to allow the inner tube to remain flexible along curves and further provide a seal within the aspiration lumen to prevent aspiration of irrigation fluid through the slots in the segments. The inner jacket may or may not facilitate torque transmission. The inner jacket may be a multilayered, reinforced tube. For example, the inner jacket includes a braided wire disposed between or sandwiched between polymer layers. The inner and / or outer layers of the inner jacket can be formed from polyether block amide, and the braided wire can be stainless steel. Alternatively, the inner jacket can be formed from polytetrafluoroethylene (PTFE). The braid can be an extremely thin, ribbon-like structure. The innermost layer can optionally be chemically etched within the inner layer and can be formed from PTFE. The inner or innermost layer can itself define a liner lumen that defines at least a portion of the aspiration lumen. The innermost layer, being PTFE, is lubricious, thus reducing potential clogging as debris is pulled through the liner lumen.

[0012] The inner jacket includes a distal end disposed adjacent the inner tip portion and a proximal end coupled to the inner tube or drive hub. This configuration results in the inner jacket lining substantially the entire aspiration lumen between the cutting tip and the proximal end of the drive hub. The inner tip portion can include an enlarged diameter portion sized approximately to the thickness of the inner jacket. The distal end of the inner jacket is disposed within the enlarged diameter portion. The proximal end of the inner jacket can be disposed near the proximal end of the inner tube. A portion of the inner jacket near the inner tube can be bonded to the drive hub using an adhesive or other suitable bonding means. The proximal and distal ends of the inner jacket are disposed on opposite sides of a flexible region of the inner tube. The inner jacket provides a seal along a curve to prevent aspiration of irrigation fluid through the slots in the segments.

[0013] In certain implementations, the cutting assembly may be a burr. The cutting tip may be a burr head secured to the inner tube. The outer tube may terminate in a tubular distal end, and the inner tube may extend through the tubular distal end. The neck of the cutting tip may extend from and adjacent the burr head, defining an opening disposed near the burr head, the opening being in fluid communication with the aspiration lumen. The inner tube is coupled to the cutting tip. The distal end of the inner tube may be secured to a proximal end of the neck of the cutting tip. The inner jacket is coaxially disposed within the inner tube. The proximal and distal ends of the inner jacket are configured to be positioned at least on opposite sides of the flexible region of the inner tube where the slot is present, such that the inner jacket has a complementary curvature or curve. The distal end of the inner jacket may be positioned adjacent the proximal end of the neck. The proximal end of the inner jacket may be positioned near the proximal end of the inner tube. A portion of the inner jacket near the inner tube may be coupled to the drive hub. The distal end of the inner jacket may or may not be attached to the cutting tip. Implementations that include an inner jacket can be combined with implementations that include irrigation channels and openings.

[0014] The cutting assembly can further include an irrigation spacer disposed within the housing hub distal to the drive hub. The irrigation spacer can be disposed within a distal cavity extending distally from the irrigation cavity. In one implementation, the irrigation spacer can have a hub defining a hole through which the inner tube and inner jacket extend, and fins extending radially away from the hub. At least one washer can be disposed between the irrigation spacer and the drive hub. The irrigation spacer provides axial spacing of the drive hub from the irrigation opening while also providing an irrigation passageway that allows robust fluid flow through the irrigation pathway.

[0015] Accordingly, a first aspect of the present disclosure is directed to a cutting assembly configured to be coupled to an irrigation source and a suction source. The cutting assembly includes a housing, an outer tube, an inner tube, and a cutting tip. The proximal end of the outer tube is coupled to the housing. The inner tube is coupled to a drive hub and rotatably coaxially disposed within the outer tube. An irrigation pathway is defined between the inner tube and the outer tube. The cutting tip is affixed to the inner tube. An inner jacket is coupled to the drive hub and coaxially disposed within the inner tube. An suction pathway is defined within the inner jacket. The inner jacket is configured to provide a fluid seal between the suction pathway and the irrigation pathway.

[0016] In certain implementations, the inner tube can define a slot. A fluid seal provided by the inner jacket is configured to prevent inflow of irrigation fluid through the slot. The outer tube can include a curved portion, and the slot in the inner tube can be axially disposed along the curved portion. The inner jacket can be coupled to the drive hub at a location near where the proximal end of the inner tube is coupled to the drive hub. The inner jacket can be asynchronous with the cutting tip. The inner jacket can be a multi-layer reinforcing tube, such as a braided braid disposed between inner and outer layers of polymeric material. The braided braid can be stainless steel, and the polymeric material can be a polyether block amide.

[0017] In certain implementations, the outer tube includes an outer tip portion defining an outer window, and the inner tip portion includes an inner window such that the cutting assembly is a shaver. Alternatively, the cutting tip may be a burr head. The burr head may include a cutting element and may define an aspiration port adjacent the cutting element. An irrigation spacer may be disposed within a cavity defined by the housing. The irrigation spacer may include a hub defining a hole through which the inner tube is rotatably disposed, and fins extending radially from the hub and secured within the cavity.

[0018] According to a second aspect of the present disclosure, a cutting assembly includes a housing, an outer tube, and an inner tube. The proximal end of the outer tube is coupled to the housing and includes an outer tip portion defining an outer window. The inner tube is rotatably and coaxially disposed within the outer tube and defines a suction lumen configured to be in fluid communication with a suction source. The inner tube includes an inner tip portion defining an inner window, and a gap is defined between the inner and outer tip portions. The outer tube defines an irrigation channel extending longitudinally from near the proximal end and configured to be in fluid communication with an irrigation source. The outer tube further defines irrigation openings at locations near the outer window and the inner window, configured to provide fluid communication between the irrigation channel and the gap. The irrigation openings can be disposed near the outer window. The outer tube can include a curved portion, and the inner tube can include a flexible region. The irrigation openings can be disposed distal to the flexible region.

[0019] According to a third aspect of the present disclosure, a cutting assembly includes a housing, an outer tube, and an inner tube. The outer tube includes a distal end and a curved portion for angling the distal end relative to a longitudinal axis. The inner tube is rotatably and coaxially disposed within the outer tube and includes a flexible region passing through the curved portion of the outer tube. The cutting tip is secured to the inner tube and angled relative to the longitudinal axis. The outer tube defines an irrigation channel configured to be in fluid communication with an irrigation source. The irrigation channel is fluidly isolated from the flexible region of the inner tube. The outer tube further defines an irrigation opening disposed distal to the flexible region and configured to provide fluid communication between the irrigation channel and a gap between the cutting tip and the outer tube.

[0020] In certain implementations, the outer tube can include an outer tip portion defining an outer window, and the cutting tip can define an inner window such that the cutting assembly is a shaver. Alternatively, the cutting tip can be a burr head. The outer tube can include a curved portion, and the irrigation channel can pass through the curved portion. The inner tube can include a segment defining a flexible region. The irrigation channel is fluidly isolated from the segment. The outer tube can be unitary, and the irrigation channel is encapsulated within the outer tube. Alternatively, a hypotube can be disposed within and coupled to the outer tube, and the irrigation channel is defined between the outer tube and the hypotube. The irrigation opening can be a recess defined at the distal end of the irrigation channel. The irrigation channels can be four irrigation channels equally spaced radially about the longitudinal axis, and the irrigation openings can be four irrigation openings equally spaced radially about the longitudinal axis. The housing can define an irrigation cavity, an opening through which the inner tube extends, and recesses in fluid communication with the openings and the irrigation channel. The recesses in the housing can be in a cross-shaped configuration or other suitable configuration.

[0021] Advantages of the present disclosure will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view of a cutting assembly of a surgical instrument; [Figure 2] FIG. 2 is a cross-sectional view of the cutting assembly of FIG. 1 taken along section line 2-2. [Figure 2A] FIG. 2B is a detailed view of a portion of the cutting assembly within circle 2A. [Figure 3] FIG. 3 is an axial cross-sectional view of the cutting assembly of FIG. 1 taken along section line 3-3. [Figure 4] FIG. 4 is an axial cross-sectional view of the cutting assembly of FIG. 1 taken along section line 4-4. [Figure 5] 1 is an exploded view of the distal portion of the cutting assembly, showing the inner and outer tip portions exploded from the inner and outer tubes, respectively, so that the irrigation openings are visible. [Figure 6] 6 is an axial cross-sectional view of the housing of the cutting assembly of FIG. 1 taken along section line 6-6. [Figure 7] FIG. 10 is a rear perspective view of the hub of the cutting assembly. [Figure 8] FIG. 10 is an exploded view of a cutting assembly according to another implementation, in which the inner jacket is configured to be coaxially disposed within the inner tube. [Figure 9] 9 is a cross-sectional view of the inner and outer tip portions of FIG. 8 with an inner jacket bonded to the inner tip portion. [Figure 10] FIG. 10 is a cross-sectional view of a housing with an inner jacket coupled to a drive hub of a cutting assembly. [Figure 11] FIG. 1 is a perspective view of a cutting assembly of a surgical instrument; [Figure 12] FIG. 12 is a cross-sectional view of the cutting assembly of FIG. 11 taken along section line 12-12. [Figure 12A] FIG. 12B is a detailed cross-sectional view of a portion of the cutting assembly within circle 12A. [Figure 13] FIG. 10 is a detailed cross-sectional view of another portion of the cutting assembly within rectangle 13. [Figure 14] FIG. 10 is a detailed cross-sectional view of another portion of the cutting assembly within rectangle 13. DETAILED DESCRIPTION OF THE INVENTION

[0023] FIG. 1 illustrates a cutting assembly 10 configured to resect tissue. The cutting assembly 10 of FIG. 1 can be considered an angled shaver. The cutting assembly 10 is configured to be removably coupled to a main instrument (not shown), which can include one or more of a motor, an irrigation source, and a suction source. While the main instrument can be reused for multiple procedures, the cutting assembly 10 can be a disposable component. One exemplary main instrument suitable for the present application is sold under the trade name ESSx Microdebrider, manufactured by Stryker Corporation (Kalamazoo, Michigan), and / or disclosed in commonly owned U.S. Patent No. 6,152,941, issued November 28, 2000, and International Publication No. WO 2021 / 224862, issued November 11, 2021, the contents of which are incorporated herein by reference in their entireties.

[0024] The cutting assembly 10 includes a housing hub 12 and a tube assembly 14 coupled to the housing hub 12. The tube assembly 14 includes at least an outer tube 16 and an inner tube 18 rotatably disposed within the outer tube 16. The inner tube 18 is configured to be coupled to an electric motor of the main equipment and is further configured to be rotated within the outer tube 16 by the electric motor. A drive hub 20 is rigidly coupled to the inner tube 18 and includes a key 22 and other features configured to releasably engage a complementary component of the main equipment.

[0025] The drive hub 20 and inner tube 18 can define an aspiration lumen 24 in fluid communication with a cutting tip 26 disposed at the distal end of the tube assembly 14. The aspiration lumen 24 can define an aspiration pathway. The aspiration pathway is configured to be placed in fluid communication with a suction source when the cutting assembly 10 is removably coupled to a primary instrument. Relative rotation of the inner and outer tubes 16, 18 allows excised tissue to be drawn through the cutting tip 26, and other debris and fluids can likewise be aspirated from the surgical site. Material aspirated through the inner tube 18 passes through a curved portion 28 of the tube assembly 14 and through the housing hub 12 for collection via the primary instrument. Further explaining, aspiration of fluids through the curved portion of the rotatable tube (which further provides irrigation through the tube assembly) is associated with a technical challenge overcome using the cutting assembly 10 of the present disclosure.

[0026] The housing hub 12 defines an irrigation cavity 30 or lumen. A seal 32 is coupleable to the housing hub 12 and defines an opening 34 in fluid communication with the irrigation cavity 30. One suitable seal for the present application is disclosed in the above-referenced International Publication WO 2021 / 224862. The seal 32 is configured to be disposed in sealing relation with a complementary feature of a primary instrument to prevent fluid escape during irrigation delivered via a surgical instrument.

[0027] The tube assembly 14 extends distally from the housing hub 12. The outer tube 16 may be rigidly coupled to the housing hub 12. The inner tube 18 may rotate within the outer tube 16 and, therefore, relative to the housing hub 12. When the drive hub 20 of the cutting assembly 10 is coupled to the main instrument, relative axial movement between the inner tube 18 and the outer tube 16 is prevented. When the cutting assembly 10 is removed from the main instrument, slight relative axial movement between the inner tube 18 and the outer tube 16 may be permitted.

[0028] The cutting tip 26 can define a cutting window such that the cutting assembly 10 is a shaver. With further reference to FIG. 5 , the cutting assembly 10 includes an outer tip portion 36 and an inner tip portion 38. The outer tip portion 36 is rigidly coupled to the outer tube 16. In one implementation, the outer tip portion 36 includes a collar 40 configured to be welded to the outer tube 16 (at the interface shown in FIG. 5 ). Distal to the collar 40, the outer tip portion 36 can include a thinned region 41. The thinned region 41 has an outer diameter smaller than the outer diameter of the collar 40. The thinned region 41 of the outer tip portion 36 provides cutting teeth 44 positioned adjacent to a more clearly defined outer window 42, improving visibility of the cutting tip 26 by the surgeon. The thinned region 41 can be formed by plunge grinding or other suitable manufacturing techniques. The thinned region 41 can be tapered, for example, in a direction toward the outer window 42 defined by the outer tip portion 36.

[0029] The inner tip portion 38 is rigidly coupled to the inner tube 18. The inner tip portion 38 defines an inner window 46, and the cutting teeth 48 may be disposed adjacent the inner window 46. The inner and outer windows 42, 46 may collectively be considered to form the cutting window of the cutting assembly 10. When the inner tip portion 38 is rotatably disposed within the outer tip portion 36, the cutting teeth 44, 48 intersect with each other in a shearing action to resect tissue. An element 50 for minimizing jamming of the cutting assembly 10 may be disposed within the inner tip portion 38, as disclosed in the aforementioned International Publication WO 2018 / 013906, published January 18, 2018, the contents of which are incorporated herein by reference in their entirety.

[0030] 2 and 2A, the curved portion 28 of the tube assembly 14 can include a curved portion 52 of the outer tube 16 and a flexible region 54 of the inner tube 18. The outer tube 16 can be rigid or malleable, and thus the curved portion 52 of the outer tube 16 generally defines the angled shape of the tube assembly 14. The curved portion 28 can be formed at any suitable angle, which is often dictated by the type of procedure. For example, the angle can be 30°, 60°, or 90°, or can be further limited only by the torque transmission capabilities of the flexible region 54 of the inner tube 18. It is further understood that the curved portion 28 of the tube assembly 14 can be positioned at any axial location between the housing hub 12 and the cutting tip 26, and the curved portion 28 can be oriented in any radial direction relative to the housing hub 12 (e.g., upward, downward, or sideways). These parameters are similarly dependent on the type of procedure. For example, the proximal curve may be indicated for spine surgery, the medical curve may be indicated for general thoracic surgery, and the distal curve may be indicated for ear, nose, and throat surgery. Figure 2 shows a distal curve with an angle of approximately 30° between opposing portions of the tube assembly 14 opposite the curved portion 28. It is further contemplated that another tube may be coaxially positioned outside of the outer tube 16 to provide a structure that provides for rotation of the cutting window independent of the curved portion 28 of the tube assembly 14.

[0031] FIG. 2A best illustrates an exemplary implementation of the flexible region 54 of the inner tube 18. The flexible region 54 can define a slot. In one example, the flexible region includes segments 56 interlocked with one another to define the slot. These segments 56 can be castellated as shown, although other interlocking geometries are contemplated. The interlocking of the segments 56 provides for the transmission of torque as the inner tube 18 is rotated by the main equipment motor. Additionally or alternatively, the inner tube 18 can include a helical, wound, or braided feature configured to transmit torque around the curved portion 28. For less complex geometries, the segments 56 define smaller slots that can result in less irrigation fluid suction loss and / or less irrigation fluid inflow. Despite the relatively smaller slots, the improved suction performance of the cutting assembly 10 remains a significant improvement. This importance is particularly evident in implementations in which the cutting assembly 10 also provides irrigation via the tube assembly 14, often simultaneously with suction. It is contemplated that the segment 56 may be present throughout the entire inner tube 18, or, as shown in FIG. 8 , only in the portion of the inner tube 18 that includes the flexible region 54. The extent to which the flexible region 54 forms the length of the inner tube 18 may depend on the deflection requirements of the tube assembly 14. For example, a larger angle of curvature and / or a smaller radius of curvature may require a relatively longer inner tube 18 formed from the flexible region 54. In exemplary implementations, the flexible region 54 forms less than 20% of the length of the tube assembly 14, and more specifically, less than 20% of the length of the inner tube 18. Minimizing the distance over which the flexible region 54 forms the length of the inner tube 18 can reduce whipping or chatter of the inner tube 18 when rotated at relatively high speeds. Additionally, by making the length of the flexible region 54 relatively short, fewer segments 56 are required, which better preserves torque transmission from the drive hub 20 to the inner window 46 .Even though the tolerances between segments 56 are very close, cumulative buildup can result in some lag between drive hub 20 and inner window 46. By reducing the number of segments 56, any lag can be reduced.

[0032] A gap 58 may be defined between the outer tip portion 36 and the inner tip portion 38 (best shown in FIG. 9B ). This gap 58 not only provides clearance for rotation of the inner tip portion 38 within the outer tip portion 36, but also provides clearance for irrigation evacuation from the cutting assembly 10 at the surgical site. Specifically, fluid may be channeled through the gap 58 and may evacuate around the outer window 42. The gap 58 is configured to be placed in fluid communication with an irrigation source. With further reference to FIG. 3 , the outer tube 16 defines an irrigation channel 60 extending longitudinally along the length of the outer tube 16. This irrigation channel 60 is in fluid communication with the irrigation cavity 30 of the housing hub 12 and, therefore, is in fluid communication with the irrigation source when the cutting assembly 10 is coupled to a primary instrument. In the exemplary implementation shown in FIG. 3 , the irrigation channel 60 is defined by the structure of the outer tube 16 itself. In other words, the outer tube 16 may be integral in structure and encapsulate the irrigation channel 60. The outer tube 16 can be formed with the irrigation channels 60 by an extrusion process. Alternatively, the outer tube 16 can define longitudinal slots or recesses, and a hypotube (not shown) or intermediate tube can be secured within the outer tube 16 to define the slotted irrigation channels 60. As best shown in FIG. 3 , this configuration provides irrigation channels 60 defining an irrigation path that is fluidly isolated from the aspiration lumen 24, particularly along the bend 28. Irrigation fluid therefore passes through the bend 28 toward the gap 58 without risk of unwanted entrainment into the aspiration lumen 24 through the slots between the segments 56. FIG. 3 illustrates four irrigation channels 60 spaced equiangularly radially about the axis of the tubing assembly 14. More or fewer irrigation channels 60 are envisioned, and the irrigation channels 60 can be arranged in any suitable configuration.

[0033] The outer tube 16 further defines irrigation openings 62 that provide fluid communication between the irrigation channels 60 and the gap 58 defined between the inner tip portion 38 and the outer tip portion 36. With reference to FIGS. 4 and 5, the irrigation openings 62 may be slots defined by the inner surface of the outer tube 16. In the illustrated implementation, the irrigation openings 62 may be effectively formed by the inner thickness 64 of the outer tube 16, where the irrigation channels 60 terminate to effectively open into the gap 58 as shown in FIG. 5 (see FIG. 3). However, it is contemplated that the irrigation openings 62 may take on or be formed in any suitable geometry to provide fluid communication between the irrigation channels 60 and the gap 58. Furthermore, the irrigation openings 62 may be equiangularly spaced radially or in any suitable configuration about the axis of the tube assembly 14. Additionally, more or fewer irrigation channels 60 are contemplated.

[0034] The irrigation channel 60 passes through the bend 28, and because the irrigation channel 60 is fluidly isolated from the inner tube 18 around the bend 28, the irrigation opening 62 is located distal to the bend 28. The irrigation opening 62 may be located distal to the most distal segment 56 of the plurality of segments 56 to eliminate the possibility of irrigation fluid being aspirated through the slot. In certain implementations, the irrigation channel 60 is located near or adjacent to the inner and outer tip portions 36, 38. The irrigation opening 62 is thus near the cutting tip 26 but redirects fluid from the irrigation channel 60 to the gap 58 distal to the bend 28. Irrigation fluid exits the cutting assembly 10 through the cutting tip 26.

[0035] 6 and 7 illustrate the fluid communication established between the irrigation channel 60 and the irrigation cavity 30 of the housing hub 12. As previously described, the inner tube 18 is rotatable relative to the housing hub 12, which therefore defines an irrigation opening 66 through which the inner tube 18 extends (see also FIG. 2). The housing hub 12 may further define a recess 68 extending from the irrigation opening 66 in alignment with the irrigation channel 60, as best shown in FIG. 6. More particularly, assembly of the cutting assembly 10 may require rigidly coupling the outer tube 16 to the housing hub 12 in a single rotational orientation to rotationally align the recess 68 and the irrigation channel 60. The cruciform configuration provides for irrigation fluid to flow into the irrigation cavity 30 of the housing hub 12, further directed through the recess 68 and the irrigation channel 60. An irrigation path that is completely fluidly separated from the aspiration path optimizes irrigation and aspiration performance, particularly on instrumentation involving curves. It is contemplated that in alternative implementations, the tube assembly 14 may be straight and the remaining aspects of the cutting assembly 10 may be as described herein. Such straight implementations may not include the segment 56, and the inner tube 18 may be of rigid construction.

[0036] In alternative implementations, certain modifications can be made to either the tube assembly 14 and / or the housing hub 12 to improve fluid flow between the irrigation cavity 30 and the irrigation channels 60. For example, unlike the recesses 68 and irrigation channels 60, which are rotationally aligned in a single rotational orientation, the recesses 68 and / or irrigation channels 60 can provide fluid communication in any rotational orientation. There may be more than four recesses 68, and / or the recesses 68 can subtend a larger arc than in the implementation shown in FIG. 6 . Additionally or alternatively, the irrigation channels 60, or at least the proximal openings into the irrigation channels 60, can also subtend a relatively larger arc, such that at least a portion of one of the plurality of irrigation channels 60 is in fluid communication with at least a portion of one of the plurality of recesses 68 in any rotational orientation between the tube assembly 14 and / or the housing hub 12. In another example, the proximal end of the outer tube 16 can include an inlet opening (not shown) in communication with the irrigation channels 60. This inlet opening may be similar to the irrigation opening 62 previously described, which extends radially inward from the outer diameter of the outer tube 16. While the irrigation channel 60 shown in FIG. 6 is defined within the proximal edge or end of the outer tube 16 and is perhaps limited in size, the irrigation opening may be a larger sized irrigation opening to allow a greater flow rate of fluid from the irrigation cavity 30 to the irrigation channel 60. In yet another example, a seal (not shown) may be disposed between the inner tube 18 and the outer tube 16 near or adjacent the proximal end of the tubing assembly 14. This seal may be a dynamic seal configured to engage with the rotating inner tube 18. The seal may prevent fluid from entering the annular space between the inner tube 18 and the outer tube 16, thereby reducing the effectiveness of the irrigation fluid entering the irrigation channel 60. In other words, only a small portion of the irrigation fluid would otherwise enter the annular space, resulting in less fluid entering the irrigation channel 60.A seal placed near the opening (or inlet opening) prevents irrigation fluid from entering the annular space, thus directing all irrigation fluid into the irrigation channel 60 and improving the performance of the cutting assembly 10.

[0037] 8-10 are directed to an alternative embodiment of the cutting assembly 10 in which the irrigation fluid is isolated from potential fluid communication with the suction. Like numerals refer to like components, and the tubing assembly 14 includes an outer tube 16 having a curved portion 52, an inner tube 18 having a flexible region 54. The tubing assembly 14 includes an inner jacket 70 coaxially disposed within the inner tube 18. More specifically, the inner jacket 70 can have an outer diameter approximately the same as the inner diameter of the inner tube 18. The inner jacket 70 can be considered a sleeve or liner.

[0038] The inner jacket 70 has mechanical properties configured to enable the inner tube 18 to maintain flexibility along the curve 28 and further provide a seal within the aspiration lumen 24 to prevent aspiration of irrigation fluid through the slots in the segments 56. The inner jacket 70 may or may not facilitate torque transmission. Known thin-walled monopolymers sometimes tend to kink when extended in a curved configuration or are too large for typical surgical instrumentation. The inner jacket 70 overcomes these drawbacks by being a multilayered, reinforced tube that advantageously achieves a thinner wall thickness without the above-mentioned kink. In one implementation, the inner jacket 70 includes a braided wire disposed or sandwiched between polymer layers. The braided wire 72 is shown in FIG. 8. More specifically, the inner and / or outer layers of the inner jacket 70 may be formed from polyether block amide, sold under the trade name PEBAX by Arkema SA (Colombes, France), and the braided wire 72 may be stainless steel. Alternatively, the inner jacket 70 may be formed from polytetrafluoroethylene (PTFE). The braid may be an extremely thin, ribbon-like structure. The innermost layer may optionally be chemically etched into the inner layer and may be formed from PTFE. The inner or innermost layer may itself define a liner lumen 80, which defines at least a portion of the aspiration lumen 24. The PTFE innermost layer is lubricious, thus reducing potential clogging as debris is pulled through the liner lumen 80.

[0039] 9 and 10 , the inner jacket 70 includes a distal end 74 disposed adjacent the inner tip portion 38 and a proximal end 76 coupled to the inner tube 18 or drive hub 20. This construction results in the inner jacket 70 lining substantially the entire aspiration lumen 24 between the cutting tip 26 and the proximal end of the drive hub 20. The thickness of the inner jacket 70 allows the inner tip portion 38 to include an enlarged diameter portion 78 sized approximately to the thickness of the inner jacket 70. As shown in FIG. 9 , the distal end 74 of the inner jacket 70 is disposed within the enlarged diameter portion 78. Because the distal end 74 is disposed within the enlarged diameter portion 78, there is a smooth transition from the inner surface of the inner tip portion 38 to the inner jacket 70. In other words, this construction prevents the exposure of a lip or edge from the distal end 74 of the inner jacket 70 onto which aspirated material may otherwise snag. The proximal end 76 of the inner jacket 70 can be positioned near the proximal end 82 of the inner tube 18, as shown in FIG. 10 . The portion of the inner jacket 70 near the inner tube 18 can be attached to the drive hub 20 using an adhesive or other suitable attachment means. In certain implementations, the inner jacket 70 may not be attached to the inner tip portion 38 and / or the drive hub 20, but rather is free-floating in the appropriate axial position. The axial position can be maintained by engagement between the curvature of the inner jacket 70, which is complementary to each of the flexible regions 54 of the inner tube 18, and the curved portion 52 of the outer tube 16. The proximal and distal ends 76 and 74 of the inner jacket 70 are positioned on opposite sides of the flexible regions of the inner tube 18, such that the inner jacket 70 assumes a complementary curve. The inner jacket 70 provides a seal along the curve to prevent aspiration of irrigation fluid through the slots in the segments 56.

[0040] 11-14, the cutting assembly 10 may be a burr, with like numerals indicating like components relative to the shaver of FIGS. 1-10. The cutting tip 26 may be a burr head 84 coupled to an inner tube 18. The outer tube 16 may not include the outer window 42, but rather terminates in a tubular distal end 86. The inner tube 18 may extend through the tubular distal end 86, with the burr head 84 located distally of the tubular distal end 86. A neck 88 of the cutting tip 26 may extend from the burr head 84 and define an opening 90 adjacent to and located near the burr head 84, the opening 90 being in fluid communication with the aspiration lumen 24. In alternative implementations, such as endoscopic applications, a partially shielded burr head may rotate within the window.

[0041] Similar to the shaver implementation described with reference to Figures 8-10, the cutting assembly 10 can include an outer tube 16, an inner tube 18, and an inner jacket 70. As best shown in Figure 13, the inner tube 18 is coupled to the cutting tip 26, and more particularly, a distal end 92 of the inner tube 18 is fixedly attached to a proximal end 94 of a neck 88 of the cutting tip 26. The distal end 92 of the inner tube 18 and the proximal end 94 of the neck 88 can be fixed together by welding, brazing, or any other suitable joining means. The inner jacket 70 is coaxially disposed within the inner tube 18. The proximal and distal ends 76, 74 of the inner jacket 70 are configured to be positioned at least on opposite sides of the flexible region 54 of the inner tube 18 where the slot defined by the segment 56 resides, thereby providing the inner jacket 70 with a complementary curvature. In certain implementations, the distal end 74 of the inner jacket 70 can be positioned adjacent to the proximal end 94 of the neck 88. The proximal end 76 of the inner jacket 70 can be positioned near the proximal end 82 of the inner tube 18, as shown in FIG. 14. This configuration results in the inner jacket 70 effectively lining substantially the entire aspiration lumen 24 between the cutting tip 26 and the proximal end of the drive hub 20. The portion of the inner jacket 70 near the inner tube 18 can be bonded to the drive hub 20 using an adhesive or other suitable bonding means. The inner jacket 70 provides a curved or curvilinear seal to prevent aspiration of irrigation fluid through the slots in the segments 56. The distal end 74 of the inner jacket 70 may or may not be bonded to the cutting tip 26.

[0042] The cutting assembly 10 may further include an irrigation spacer 96 disposed within the housing hub 12 distal to the drive hub 20. In implementations in which the cutting assembly 10 is a shaver, interference between the closed distal ends of the outer tip portion 36 and the inner tip portion 38 prevents relative movement between the outer tube 16 and the inner tube 18. No such constraint may exist for the burr, and distal movement of the drive hub 20 within the irrigation cavity 30 may restrict or block fluid flow through the irrigation opening 66. The irrigation spacer 96 in this implementation advantageously provides axial spacing of the drive hub 20 from the irrigation opening 66 while also providing an irrigation passageway that permits robust fluid flow through the irrigation pathway. The irrigation spacer 96 may be disposed within a distal cavity 98 extending distally from the irrigation cavity 30, as shown in FIG. 14 . In one implementation, the irrigated spacer 96 can have a hub defining a hole through which the inner tube 18 and inner jacket 70 extend, and fins extending radially away from the hub. At least one washer 100 can be disposed between the irrigated spacer 96 and the drive hub 20. Further disclosure of the irrigated spacer 96 and related components is disclosed in the above-referenced International Publication WO 2021 / 224862.

[0043] The foregoing description is not intended to be exhaustive or to limit the invention to any particular form. The terminology used is intended to be words of description rather than of limitation. Many modifications and variations are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described.

Claims

1. a cutting assembly configured to be coupled to an irrigation source and a suction source, Housing and an outer tube having a proximal end coupled to the housing; A drive hub; an inner tube coupled to the drive hub and rotatably coaxially disposed within the outer tube, an irrigation pathway defined between the inner tube and the outer tube; a cutting tip having an inner tip secured to the inner tube; an inner jacket coupled to the drive hub and coaxially disposed within the inner tube, an aspiration path defined within the inner jacket, the inner jacket configured to provide a fluid seal between the aspiration path and the irrigation path; the inner tip defines an enlarged diameter portion approximately equal to a thickness of the inner jacket, the inner jacket being disposed within the enlarged diameter portion and including a distal end adjacent the inner tip.

2. The cutting assembly of claim 1 , wherein the inner tube defines a slot, and the fluid seal provided by the inner jacket is configured to prevent inflow of irrigation fluid through the slot.

3. The cutting assembly of claim 2 , wherein the outer tube includes a curved portion, and the slot in the inner tube is axially disposed along the curved portion.

4. The cutting assembly of claim 1 , wherein the inner jacket is coupled to the drive hub at a location adjacent where a proximal end of the inner tube is coupled to the drive hub.

5. The cutting assembly of claim 1 , wherein the inner jacket is not secured to the cutting tip.

6. The cutting assembly of claim 1 , wherein the inner jacket comprises a multi-layer stiffening tube.

7. The cutting assembly of claim 6 , wherein the multi-layer reinforcing tube comprises a braid disposed between inner and outer layers of polymeric material.

8. 8. The cutting assembly of claim 7, wherein the braided cord is made of stainless steel and the polymeric material is a polyether block amide.

9. 10. The cutting assembly of claim 1, wherein the outer tube includes an outer tip portion defining an outer window, and the inner tip portion includes an inner window such that the cutting assembly is a shaver.

10. The cutting assembly of claim 1 , wherein the cutting tip is a burr head.

11. The cutting assembly of claim 10 , wherein the burr head includes a cutting element and defines a suction port adjacent the cutting element.

12. 11. The cutting assembly of claim 10, further comprising an irrigation spacer disposed within a cavity defined by the housing, the irrigation spacer comprising a hub defining a hole through which the inner tube is rotatably disposed, and fins extending radially from the hub and secured within the cavity.

13. A cutting assembly as described in claim 1, wherein the distal end of the inner jacket is positioned distal to the proximal end of the cutting tip.

Images