US20130066149A1 - Endoscopic hook blade and use thereof - Google Patents

Abstract

An endoscopic surgical blade is disclosed. The blade is of a hook design, having an upper cutting surface located on the trailing edge of an arm and a lower cutting surface on the upper edge of the main body of the blade. The blade is part of an endoscopic knife assembly which also contains a knife tube and alignment ring. The endoscopic knife assembly is for use in endoscopic surgery by insertion of the assembly through a slotted cannula. The knife tube is hollow and allows the insertion of an endoscope for viewing of the surgical procedure. A method for a performing an operative procedure on a target tissue in a subject using an endoscopic knife assembly having a hook blade is also described.

Description

FIELD
• The present application relates to medical devices and, in particular, to a surgical blade for endoscopic operations.
BACKGROUND
• Endoscopic surgery is a minimally invasive surgical procedure that is performed through small incisions or natural body openings. An endoscopic procedure typically involves use of specialized devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or similar device. Comparing to open surgery, endoscopic surgery may result in shorter hospital stays, or allow outpatient treatment.
• Among more recent developments and advances in endoscopic surgical procedures, arthroscopic surgery employing the use of endoscopic devices has found widespread application. For example, endoscopic procedures have been used in effectuating carpal tunnel release with endoscopic instruments. However, there always exists a need to further improve the utility of the instrument, reduce the cost and improve the performance of endoscopic surgical procedures.
SUMMARY
• One aspect of the present application relates to a hook blade for an endoscopic knife assembly. The hook blade comprises an arm having a forward edge, a trailing edge and an upper cutting surface located on the trailing edge; a main body having an upper edge, a lower edge, a distal section, a proximate section, and a lower cutting surface located on the upper edge of the distal section; wherein the distal section of the main body angles downward from the proximate section of the main body, forming a downward angle with the proximate section of the main body, wherein the arm protrudes from the distal section of the main body and extends back towards the main body in a hook-like manner, forming a hook angle with the proximate section of the main body, and wherein the upper cutting surface and the lower cutting surface meets at a crotch forming a cutting angle between the two cutting surfaces.
• Another aspect of the present application relates to an endoscopic knife assembly. The endoscopic knife assembly comprises a knife tube having a distal end and a proximate end, a hook blade attached to the distal end, and an alignment ring attached near the proximate end.
• Yet another aspect of the present application relates to an instrument kit for implementing an endoscopic surgical procedure. The instrument kit comprises a slotted cannula for endoscopic surgical procedures and an endoscopic knife assembly comprising a hook blade, a knife tube and an alignment ring. The endoscopic knife assembly is insertable into the slotted cannula.
• Still another aspect of the present application relates to a method for a performing an operative procedure on a target tissue in a subject, comprising: making an incision to establish an entry portal, inserting a cannula having open proximal and distal ends, inserting an endoscope into the cannula, said endoscope comprising an endoscopic knife assembly having a hook blade, advancing said endoscope so that the hook blade moves distal to and is in contact with the target tissue, operatively engaging the target tissue with the hook blade, and withdrawing the hook blade back towards the cannula to perform the operative procedure on the target tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present application can be better understood by reference to the following drawings. The drawings are merely exemplary to illustrate certain features that may be used singularly or in combination with other features and the present application should not be limited to the embodiments shown.
• FIGS. 1A-F illustrate a hook blade component of an endoscopic knife assembly.FIG. 1A is a perspective view showing the hook blade component.FIG. 1B depicts a side view of the hook blade component, showing the cutting surfaces, the transition where the blade is joined to the knife tube and the taper at the end of the blade.FIG. 1C is a perspective view showing a top view of the hook blade.FIG. 1D depicts a side view of the hook blade component.FIG. 1E is a cross section view of the hook blade at thebisecting line3 inFIG. 1D depicting an exemplary angle of a cutting surface of the blade component.FIG. 1F is a perspective view of the hook blade from the back depicting the width of the blade, the transition and the extension of the lower cutting surface below the transition.
• FIGS. 2A-D illustrate an endoscopic knife assembly.FIG. 2A is a perspective view of the endoscopic knife assembly from the side.FIG. 2B is a perspective view of the endoscopic knife assembly from the top.FIG. 2C is a perspective view of the endoscopic knife assembly from the bottom.FIG. 2D is a perspective view of the endoscopic knife assembly from the front.
• FIGS. 3A-E illustrate the knife tube component of the endoscopic knife assembly.FIG. 3A is a magnified view from the side of the proximate end of a knife tube, showing the slots and the flared end.FIG. 3B is a perspective view of the proximate end of a knife tube, showing the slots and the flared end.FIG. 3C is a perspective view from the bottom of a knife tube, shown at an angle.FIG. 3D is a perspective view from the side of a knife tube.FIG. 3E is a perspective view from the top or bottom of a knife tube.
• FIGS. 4A-D illustrate the alignment ring component of the endoscopic knife assembly.FIG. 4A is a perspective view at an angle as seen from the bottom, showing the flattened bottom face of the alignment ring.FIG. 4B is a perspective view at an angle as seen from the front or back face of the alignment ring.FIG. 4C is a perspective view seen from the side of the alignment ring.FIG. 4D is a perspective view seen from the top of the alignment ring.
DETAILED DESCRIPTION
• This description is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this application. The drawing figures are not necessarily to scale and certain features of the application may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “front,” “back,” “up,” “down,” “top,” “bottom,” “upper,” “lower,” “distal,” and “proximate” as well as derivatives thereof, should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and noi malty are not intended to require a particular orientation. Terms concerning attachments, coupling and the like, such as “connected,” “mounted,” and “attached,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.
• In endoscopic surgery, it is sometimes undesirable or impractical to perform a cut of a tissue using a blade that is pushed forward outward from the end of a cannula to make the cut in a forward direction. This may be due to a variety of factors including, but not limited to, the proximity of the tissue to be cut (target tissue) to another tissue or an organ distal to the target tissue from that cannula, a lack of tension in the target tissue that would allow the blade to push the target tissue away from the cannula or the flexibility of the target tissue, for example.
• Accordingly, the present application fills a need in the art by providing a “hook blade.” The blade described herein is a low-profile blade that lacks forward facing cutting surfaces. The cutting surfaces of the blade are instead located on the trailing edge of an arm that protrudes upward from the main body of the blade (upper cutting surface) and on the forward portion of the upper surface of the main body of the blade (lower cutting surface). The arm of the blade is additionally angled back towards the main body of the blade, forming a hook. Additionally, that forward portion of the main body of the blade comprising the lower cutting surface is angled downward in front of the knife tube upon which it is mounted.
• This downward angle allows the hook blade described herein to maintain a low profile such that it can be used with a slotted cannula and does not require a mechanical means for extending the blade out the side of the knife tube, as required by some other rearward-facing endoscopic cutting devices. The presently described low-profile hook blade therefore provides several advantages over other devices including, but not limited to, the lack of moving parts required to raise the blade out of the side of the knife tube reducing the risk of malfunction or failure of the cutting instrument. An additional advantage of the present low-profile hook blade design is that the lack of said moving parts and the obligatory linkages and apparatus required to operate the extension of the blade allows the knife tube to be hollow. This allows the practitioner to extend an endoscopic camera through the hollow knife tube to allow direct visualization of the tissue and blade before, during and after the cutting of the target tissue.
• The design of the present low-profile hook blade is such that it is usable in endoscopic surgery in a manner that allows the practitioner to extend the blade through the cannula and past the target tissue without damage to surrounding tissue and/or organs. The blade is then positioned distal to the target tissue such that the target tissue can be drawn into the hook formed by the upper and lower cutting surfaces. The hook blade apparatus is then drawn back towards and into the cannula to effect a cut of the target tissue. The downward angle of the lower cutting surface portion of the main body of the blade and the backward angle of the arm assist in drawing the target tissue into the hook structure of the blade.
• One aspect of the present application relates to a hook blade for an endoscopic knife assembly, comprising: an arm having a forward edge, a trailing edge and an upper cutting surface located on the trailing edge; a main body having an upper edge, a lower edge, a distal section, a proximate section, and a lower cutting surface located on the upper edge of the distal section; wherein the distal section of the main body angles downward from the proximate section of the main body, forming a downward angle with the proximate section of the main body, wherein the arm protrudes from the distal section of the main body and extends back towards the main body in a hook-like manner, forming a hook angle with the proximate section of the main body, and wherein the upper cutting surface and the lower cutting surface meets at a crotch forming a cutting angle between the two cutting surfaces.
• In one particular embodiment, the hook angle is between about 55 degrees and about 75 degrees. In a further embodiment, the hook angle is about 65 degrees.
• In another particular embodiment, the cutting angle is between about 40 degrees and about 60 degrees. In a further embodiment, the cutting angle is about 50 degrees.
• In another particular embodiment, the downward angle is between about 150 degrees and about 175 degrees. In a further embodiment, the downward angle is between about 165 degrees.
• In one particular embodiment, the proximate section of the main body has a tapered end.
• In another particular embodiment, the main body comprises a notch on the lower edge to engage with a knife tube.
• In another particular embodiment, the arm comprises an upper radius on the upper end of the forward edge to prevent the forward edge from damaging tissue as the hook blade is advanced from a cannula. In a further embodiment, the arm further comprises a lower radius on the lower end of the forward edge to prevent the forward edge from damaging tissue as the hook blade is advanced from a cannula.
• In another particular embodiment, the hook blade has a total vertical height in the range of about 4 mm to about 5 mm.
• Another aspect of the present application relates to an endoscopic knife assembly, comprising: a knife tube having a distal end and a proximate end; a hook blade attached to the distal end; and an alignment ring attached near the proximate end, wherein the hook blade comprises an arm having a forward edge, a trailing edge and an upper cutting surface located on the trailing edge; a main body having an upper edge, a lower edge, a distal section, a proximate section, and a lower cutting surface located on the upper edge of the distal section; wherein the distal section of the main body angles downward from the proximate section of the main body, forming a downward angle with the proximate section of the main body, wherein the arm protrudes from the distal section of the main body and extends back towards the main body in a hook-like manner, forming a hook angle with the proximate section of the main body, and wherein the upper cutting surface and the lower cutting surface meets at a crotch forming a cutting angle between the two cutting surfaces.
• In another particular embodiment, the knife tube comprises one or more slots at the proximate end for the attachment of a locking assembly to the knife tube and alignment ring.
• In another particular embodiment, the slots are located on a plane that is perpendicular to the hook blade attached to the distal end of the knife tube.
• In another particular embodiment, the knife tube is marked on the top or side surface with gradations.
• In another particular embodiment, the alignment ring comprises a flattened surface that is positioned perpendicular to the hook blade attached to the distal end of the knife tube.
• In another particular embodiment, the hook blade is welded to the knife tube.
• Another aspect of the present application relates to an instrument kit for implementing an endoscopic surgical procedure comprising: an endoscopic knife assembly comprising a hook blade, a knife tube and an alignment ring, wherein the blade comprises an upper cutting surface located on a trailing edge of an arm and a lower cutting surface located on an upper edge of a main body of the blade, the cutting surfaces meeting at an angle at a crotch; and a slotted cannula for endoscopic surgical procedures, wherein the endoscopic knife assembly is insertable into the slotted cannula.
• In one particular embodiment, the main body of the blade comprises a notch on a lower edge of the main body to engage with the knife tube.
• Another aspect of the present application relates to a method for a performing an operative procedure on a target tissue in a subject, comprising: making an incision to establish an entry portal, inserting a cannula having open proximal and distal ends, inserting an endoscope into the cannula, said endoscope comprising an endoscopic knife assembly having a hook blade, advancing said endoscope so that the hook blade moves distal to and is in contact with the target tissue, operatively engaging the target tissue with the hook blade, and withdrawing the hook blade back towards the cannula to perform the operative procedure on the target tissue.
• In one particular embodiment, the operative procedure is an endoscopic surgical procedure selected from the group consisting of carpal tunnel release, cubital tunnel release, plantar fascia release, lateral release for patella realignment, release of the extensor tendons, release of the posterior and other compartments of the leg, and forearm fascial release.
• In another particular embodiment, the cannula is a clear cannula.
• In another particular embodiment, the cannula comprises an open slot extending along the length of the cannula.
• In another particular embodiment, the inserting of said endoscope comprising an endoscopic knife assembly having a hook blade is preceded by the insertion of another endoscope comprising a means for visualization of the target tissue. In a further embodiment, the cannula is a clear cannula. In a further embodiment, the method further comprises visualization of anatomic structures surrounding the cannula.
• In another particular embodiment, the establishing an entry portal comprises making an incision.
• One aspect of the present application is a scope-mounting blade or endoscopic knife assembly for endoscopic surgery. The knife assembly comprises a hook blade, a knife tube and an alignment ring. The assembly is assembled by affixing the alignment ring and the blade onto the knife tube.
• The hook blade is made from materials commonly used for surgical blades or scalpels, such materials include, but are not limited to, hardened and tempered steel, stainless steel, high carbon steel, titanium, alloys and ceramic. In one embodiment, the blade is made from SAE 440A stainless steel. In a preferred embodiment, the blade is made from Hitachi GIN-5 SST-MODIFIED 440-A stainless steel. The blade is optionally flash electropolished. The cutting edges are machine finished and must be sharp. In a particular embodiment, the steel of the blade is heat-treated to Rockwell C hardness of about 50-72. In a more particular embodiment, the steel of the blade is heat-treated to Rockwell C hardness of 58-64.
• An embodiment of the hook blade is shown inFIGS. 1A-1F. As shown inFIG. 1A, thehook blade100 comprises anarm50 having aforward edge52 and a trailingedge54, and amain body60 having anupper edge62 and alower edge64. The upper cutting surface1 and thelower cutting surface2 are formed on the trailingedge54 of thearm50 and theupper edge62 of the main body. Thearm50 is oriented in a hook configuration trailing anarm50 of theblade100. The upper cutting surface1 and thelower cutting surface2 meet at acentral crotch5 and form acutting angle4 between the two surfaces. The cutting surfaces1 and2 are sharp cutting surfaces, while no other surfaces of thehook blade100 are intended to be cutting surfaces.
• In one embodiment, the cuttingangle4 is between about 40 and about 60 degrees. In another embodiment, the cuttingangle4 is between about 45 and about 55 degrees. In another embodiment, the cuttingangle4 is about 50 degrees.
• Referring now toFIG. 1B, thedistal section80 of themain body60 extends downward and forms a downward angle8 with theproximal section70 of themain body60. In certain embodiments, the interior angle8 is between about 150 and about 175 degrees. In other embodiments, the interior angle8 is between about 160 and about 170 degrees. In yet another embodiment, the interior angle8 is about 165 degrees.
• Thearm50 protrudes upward from thedistal section80 and angles back towards the main body in a hook-like manner, forming ahook angle56 with theproximate section70 of themain body60. In one embodiment, thehook angle56 is between about 55 and about 75 degrees. In another embodiment, thehook angle56 is between about 60 and about 70 degrees. In another embodiment, thehook angle56 is about 65 degrees.
• In one embodiment, thewidth6 of thearm50 is between about 1.5 and about 2.0 mm. In another embodiment, thewidth6 is between about 1.65 and 1.85 mm. In another embodiment, thewidth6 is about 1.778 mm.
• Referring again toFIG. 1B, in certain embodiments, the upper end of theforward edge52 of thearm50 has anupper radius10 in order to prevent it from damaging tissue as thehook blade100 is advanced from a cannula. In one embodiment, theupper radius10 has a radius measurement of between about 1.0 mm and 2.5 mm. In another embodiment, theupper radius10 has a radius measurement of about 2.032 mm.
• In other embodiments, the lower end of theforward edge52 of thearm50 has alower radius11 in order to prevent it from damaging tissue as the hook blade apparatus is advanced from the cannula. In one embodiment, thelower radius11 has a radius measurement between about 4 mm and 10 mm. In another embodiment, thelower radius11 has a radius measurement of about 0.635 mm.
• In certain embodiments, thedistance12 between theupper radius10 and thelower radius11 on theforward edge52 of thearm50 is between about 2.5 mm and 2.8 mm. In one embodiment, thedistance12 is about 2.62 mm.
• Referring again toFIG. 1B, in certain embodiments, thearm50 is angled back such that the horizontal distance13 in a plane with themain body60 of theblade100 from the most forward point on thelower radius11 to the top and farthest back point on cutting surface1 is between about 3.4 and 3.8 mm. In one embodiment, the horizontal distance13 is between about 3.5 and 3.7 mm. In another embodiment, the horizontal distance13 is about 3.63 mm.
• In certain embodiments, theheight15 of theproximate section70 of themain body60 is between about 1 mm and about 1.8 mm. In one embodiment, theheight15 is between about 1.2 mm and about 1.6 mm. In another embodiment, theheight15 is between about 1.3 mm and about 1.4 mm. In another embodiment, theheight15 is about 1.42 mm.
• In certain embodiments, thevertical distance16 between the top and farthest back point on cutting surface1 and thebottom edge64 of theproximate section70 is between about 2.4 mm and about 3.0 mm. In one embodiment, thevertical distance16 is between about 2.6 mm and about 2.8 mm. In another embodiment, thevertical distance16 is about 2.69 mm. In order to insure that, during manufacture, thehook blade100 is consistently joined to theknife tube200 in the same location, thelower edge64 of themain body60 comprises anotch66. During assembly of the endoscopic knife assembly, thenotch66 is butted against the front of the knife tube. Following the positioning of the blade on the knife tube, theblade100 is laser welded all around to the knife tube. In one embodiment, the strength of the weld is tested by applying torque to the unit, for example about 10 in-lbs of torque. In certain embodiments, thedepth21 of thenotch66 is between about 0.025 mm and about 0.18 mm. In one embodiment, thedepth21 of thenotch66 is between about 0.051 mm and about 0.1524 mm. In another embodiment, thedepth21 of thenotch66 is about 0.102 mm.
• Additionally, in certain embodiments, thehorizontal distance22 between thenotch66 and the focus of angle8 is between about 1.6 mm and about 2.1 mm, preferably about 1.85 mm. In another embodiment, the horizontal distance23 between thenotch66 and the top and farthest back point on cutting surface1 is between about 3.0 mm and about 7.0 mm, preferably between about 4.0 mm and about 5.5 mm, and more preferably about 4.78 mm or 4.826 mm. In yet another embodiment, thehorizontal distance24 between thenotch66 and the top and farthest back point on cuttingsurface2 is between about 2.8 mm and about 3.3 mm, preferably about 3.05 mm.
• In order to prevent the hook blade from catching on the interior surface of the cannula when theblade100 is drawn backwards through the cannula tube, theblade100 has a tapered trailingedge27. In one embodiment, the horizontal length of the tapered trailingedge27 is between about 2.5 mm to about 10 mm, more particularly about 3.0 mm to about 5.0 mm. In another embodiment, the horizontal length of the tapered trailingedge27 is about 3.81 mm. In some embodiments, the tapered trailingedge27 has a blunt end, with adepth28 of between about 0.1 mm to about 0.4 mm, more particularly about 0.254 mm.
• Referring now toFIG. 1C, in certain embodiments, thetotal length14 of theblade100 from the leading point of thelower radius11 to the trailing end of theproximate section70 is between about 15 mm and about 40 mm. In one embodiment, thetotal length14 of theblade100 is between about 20 mm and about 330 mm. In another embodiment, thetotal length14 of theblade100 is about 26.4 mm.
• Referring now toFIG. 1D, in certain embodiments, thevertical distance19 between the center of thelower radius11 and thebottom edge64 of the main body60 (where it is affixed to the knife tube) is between about 0.9 mm and about 1.2 mm. In one embodiment, thevertical distance19 is between about 1.0 mm and about 1.1 mm. In another embodiment, thevertical distance19 is about 1.04 mm.
• In some embodiments, the upper cutting surface1 andlower cutting surface2 form a sharp angle at thecrotch5. In other embodiments, the upper cutting surface1 andlower cutting surface2 meet at thecrotch5 with a ground curved corner. In one embodiment, the grinding of the upper cutting surface1 andlower cutting surface2 cutting surfaces where they meet at thecrotch5 has a maximum radius of about 0.65 mm. In a particular embodiment, the grinding at thecrotch5 has a maximum radius of about 0.5 mm. In a more particular embodiment, the grinding at thecrotch5 has a maximum radius of 0.381 mm.
• Referring again toFIG. 1D, in one embodiment, thehorizontal distance25 between thenotch66 and the focus ofradius11 is between about 7.5 mm and about 8.0 mm, preferably about 7.77 mm.
• In order to maintain uniform measurement of the gradations on theknife tube200 and the cutting surfaces of thehook blade100, thehorizontal distance26 between thenotch66 and thecrotch5 is preferably 5.41 mm. Alternatively, ahorizontal distance26 can be chosen for a particular model or lot of thehook blade100 within a range of about 2.5 mm to about 10 mm.
• Referring again toFIG. 1D, in a particular embodiment, thevertical distance20 between thecrotch5 and thebottom edge64 of the main body60 (where it is affixed to the knife tube) is between about 0.6 mm and about 0.9 mm. In another embodiment, thevertical distance20 is between about 0.7 mm and about 0.8 mm. In a more particular embodiment, thevertical distance20 is about 0.762 mm.
• FIG. 1E shows a cross-sectional view of thedistal section80 of themain body60 from line3-3 inFIG. 1D. In one embodiment, thecross-sectional depth82 of thedistal section80 is between about 1.5 mm and 2.0 mm. In another embodiment, thecross-sectional depth82 of thedistal section80 is between about 1.6 mm and 1.9 mm. In another embodiment, thecross-sectional depth82 of thedistal section80 is about 1.778 mm.
• Similarly, in one embodiment, the cross-sectional depth of the arm50 (i.e., the cross-section fromline3′-3′ inFIG. 1D) is between about 1.5 mm and 2.0 mm. In another embodiment, thecross-sectional depth82 of thearm50 is between about 1.6 mm and 1.9 mm. In another embodiment, thecross-sectional depth82 of thearm50 is about 1.778 mm.
• Referring again toFIG. 1E, in certain embodiments, the cutting surfaces1 and2 each contains a subsurface a and a subsurface b that forms asurface angle29 with the subsurface a. In certain embodiments, the cuttingangle29 of the cutting surfaces1,2 is between about 35 degrees and about 45 degrees, more particularly about 40 degrees. In certain embodiments, the subsurfaces a and b each have a width30 that is between about 0.8 mm and about 1.0 mm, more particularly about 0.91 mm.
• Referring now toFIG. 1F, in certain embodiments, the totalvertical height17 of thehook blade100 from the bottom ofradius11 to the top and farthest back point on cutting edge1 is between about 4.0 mm and about 5.0 mm. In one embodiment, the totalvertical height17 is between about 4.35 mm and about 4.65 mm. In another embodiment, the totalvertical height17 is about 4.445 mm.
• In certain embodiments, thethickness18 of thehook blade100 is between about 0.50 mm and about 0.75 mm. In one embodiment, thethickness18 of thehook blade100 is between about 0.60 mm and about 0.67 mm. In another embodiment, thethickness18 of the hook blade is about 0.635+/−0.013 mm.
• Referring again toFIG. 1F, in certain embodiments, thedistal section80 of themain body60 extends below thebottom edge64 of the main body60 (where it affixes to the knife tube) adistance9 of between about 1.5 and 1.9 mm. In another embodiment, thedistance9 is between about 1.6 and about 1.8 mm. In another embodiment, thedistance9 is about 1.68 mm.
• FIGS. 2A-2D show a hook-blade assembly300 with ahook blade100 mounted on aknife tube200. As shown inFIG. 2A, thehook blade100 is attached to theknife tube200, such that thenotch66 of theblade100 is butted up against thedistal end202 of theknife tube200. In one embodiment, thehook blade100 is welded to theknife tube200.
• In one embodiment, the top and farthest back point of upper cutting surface1 extends adistance31 of about 3.0 mm to about 7.0 mm, more particularly about 4.0 mm to about 5.5 mm forward of the knife tube. In a most particular embodiment, thedistance31 is about 4.826 mm or 4.78 mm.
• In a particular embodiment, thelength32 of theknife tube200 is from about 100 mm to about 140 mm, preferably from about 114.3 mm to about 119.4 mm. In a more preferred embodiment, thelength32 of theknife tube200 is about 116.84 mm.
• Theknife tube200 can optionally be marked on the top or side surface with gradations as exemplified inFIG. 2B to show the distance to thecrotch5 of the cutting surfaces. For example,major gradations 34 can be made to show each centimeter in distance from thecrotch5, withminor gradations 36 between them to show each 1, 2, 2.5 or 5 millimeters. While the gradations can be applied to the knife tube by any means known in the art, it is preferable to lasermark the gradations on theknife tube200 for accuracy and permanence. Additionally, theknife tube200 can also be marked in a similar manner with additional information, for example on the bottom or a side surface of theknife tube200. Exemplary markings may include, but are not limited to, a maker's mark, part number, lot number and an indication that the endoscopic knife assembly is intended for only a single use (see, e.g.,FIG. 2C).
• Referring again toFIG. 2A, analignment ring250 is affixed near the proximate end of theknife tube200. In one embodiment, thealignment ring250 is affixed in position on theknife tube200 using USP Class VI gamma irradiation and steam resistant epoxy adhesive during assembly. Preferably, a two part epoxy such as MASTERBOND EP42 HT™ or ARMSTRONG C-7™, or a suitable equivalent thereof is used. In one embodiment, the distance33 between thealignment ring250 and the proximate end of theknife tube200 is between about 15 mm and about 25 mm. In another embodiment, the distance33 is between about 18.67 mm and about 19.43 mm. In another embodiment, the distance33 is about 19.05+/−0.38 mm.
• The knife tube further comprisesslots37 in the proximate end that are positioned on the sides of theknife tube200, perpendicular to the blade mounted on the top of the knife tube. Theslots37 preferably extend forward to where thealignment ring250 is affixed to theknife tube100.
• The slots and alignment ring provide an attachment point for a locking device, in order to mount an endoscope to the scope-mounting blade or endoscopic knife assembly.
• FIGS. 3A-E show perspective views of aknife tube200 without an affixed blade or alignment ring and without gradations. Referring now toFIG. 3A, in one embodiment, theouter diameter38 of theknife tube200 is between about 2.8 mm and about 3.6 mm, preferably between about 3.073 mm and about 3.175 mm. In a more preferred embodiment, theouter diameter38 is about 3.124 mm.
• Referring again toFIG. 3A, in another embodiment, theknife tube200 has a flaredproximate end40. In one embodiment, about 0.2 to about 0.5 most proximate millimeters of theknife tube200 are flared. In another embodiment, about the 0.381 most proximate millimeters of theknife tube200 are flared. In another embodiment, the flaredproximate end40 has a flare angle41 of about 20 to 40 degrees, more preferably about 30 degrees. In still another embodiment, theouter diameter42 of the flaredproximate end40 of the knife tube is about 0.25 mm to about 0.45 mm, more particularly about 0.356 mm.
• Referring now toFIG. 3B, theinner diameter39 of theknife tube200 is such that an endoscope camera can be inserted into the knife tube in order to show the blade and the target tissue during a procedure. In one embodiment, theinner diameter39 is between about 2 mm and about 3.5 mm. In a particular embodiment, theinner diameter39 is between about 2.769 mm and about 2.87 mm. In a more particular embodiment, theinner diameter39 is about 2.819 mm.
• In one embodiment, theslots37 have awidth43 of between about 0.4 mm and about 1.1 mm wide, more particularly between about 0.533 mm and about 0.914 mm wide. Even more particularly, thewidth43 of the slots is about 0.6604 mm.
• FIGS. 4A-D show an embodiment of thealignment ring250 of the endoscopic knife assembly of the application. Referring now toFIG. 4A, in one embodiment, thealignment ring250 has a flattenedsurface252 that, when thealignment ring250 is affixed to theknife tube200, is oriented on the bottom of theknife tube200, i.e., opposite of the mounting of theblade100. When the endoscopic knife assembly is fully assembled, the flattenedsurface252 of the alignment ring forms a right angle with the vertical orientation of the affixedblade100, as depicted inFIG. 4B.
• In one embodiment, theinner diameter44 of the alignment ring, which must fit on the outside of theknife tube200, is between about 2.8 mm and about 3.7 mm, particularly between about 3.15 mm and about 3.175 mm. In a more particular embodiment, theinner diameter44 is about 3.15 mm.
• In a particular embodiment, theouter diameter45 of the alignment ring is between about 6 mm and about 10 mm, preferably between about 7.569 mm and about 7.671 mm. In a more preferred embodiment, theouter diameter45 is about 7.62 mm.
• As shown inFIG. 4B, in one embodiment, thedistance46 between the inner opening of the alignment ring and the flattenedsurface252, on a line perpendicular to the flattenedsurface252, is between about 0.25 mm and about 0.5 mm, preferably between about 0.330 mm and about 0.432 mm. In more preferred embodiment, thedistance46 is about 0.381 mm.
• Referring toFIG. 4C, showing a side view of the alignment ring, andFIG. 4D, showing a view from the top of the alignment ring, in one embodiment, thealignment ring250 has athickness47 of between about 1.0 mm and about 4.0 mm. In a particular embodiment, thethickness47 is between about 2.0 mm and about 3.0 mm. In a more particular embodiment, thethickness47 is about 2.54 mm.
• Thehook blade100 and theendoscopic knife assembly300 described above may be readily applied to surgical procedures such as, but not limited to, carpal tunnel release; cubital tunnel release, plantar fascia release, lateral release for patella realignment, release of radial tunnel, release of pronatar teres, release of trigger finger, release of lacertous fibrosis, release of the extensor tendons for lateral epicondylitis (tennis elbow), release of medial epicondylitis (golfer's elbow), and release of fascial compartments in the upper and lower extremity.
• Another aspect of the present application relates to an instrument kit for implementing an endoscopic surgical procedure. The instrument kit contains an endoscopic knife assembly having a hook blade and a cannula guide member including a longitudinal bore having open proximal and distal ends and an open slot extending along the length thereof communicating with the open ends, and an elongate insertion member that is slidably receivable within the cannula guide member and is configured so that at least portions thereof conform with the open distal end and the open slot of the guide member to form a smooth exterior surface in combination therewith.
• In one embodiment, the instrument kit further includes an endoscope sized for insertion into the cannula guide member for direct visualization of an operative site.
• In another embodiment, the endoscope is capable to carry a cutting instrument at a leading end.
• In another embodiment, the instrument kit further includes a second cutting instrument mountable to the leading end of the endoscope.
• In another embodiment, the instrument kit further includes a second endoscope with a second cutting instrument mounted at a leading end of the second endoscope. The second endoscope is insertable into the cannula guide member such that the cutting instrument protrudes through the open slot in the cannula guide member. The second cutting instrument may be an endoscopic knife assembly having a hook blade or an endoscopic knife assembly having another type of blade including, but not limited to, a blade comprising an upper and a lower cutting surface on the forward edge of the blade, said cutting surfaces meeting at an angle at a crotch.
• In another embodiment, the instrument kit further includes a depth gauge mountable to a leading end of the endoscope.
• In another embodiment, the instrument kit further includes a rasp member sized for insertion into the cannula guide member.
• In another embodiment, the instrument kit further includes a locking device capable of locking the endoscope and the cannula guide member into mutually fixed positions.
• In another embodiment, the instrument kit further includes a stop device mountable on the cannula guide member to prevent excessive penetration at a surgical site by the cutting instrument.
• In another embodiment, the instrument kit further includes a curved dissector.
• Another aspect of the present application relates to a method for implementing a uniportal endoscopic surgical procedure using an endoscopic knife assembly having a hook blade of the present application. In one embodiment, the method includes the steps of making an incision on a patient in need of such endoscopic surgical procedure at a location proximate an operation site to establish an entry portal, inserting an elongate insertion member into a longitudinal bore of an elongate transparent cannula having open proximal and distal ends and an open slot extending along the length of the cannula, the elongate insertion member being configured to form a smooth exterior surface at the open distal end of the cannula when fully inserted into the cannula; introducing the distal end of the cannula/insertion member combination into the entry portal and advancing the combination a predetermined distance relative to the operation site; withdrawing the insertion member while permitting the cannula to remain in place at the operation site; inserting a first endoscope into the cannula for direct visualization of anatomic structures surrounding the cannula and positioning of the cannula at the operative site; withdrawing the first endoscope from the cannula; mounting an endoscopic knife assembly having a hook blade on a leading end of a second endoscope; inserting the endoscope with the endoscopic knife assembly having a hook blade into the cannula such that the hook blade protrudes into the open slot in the cannula, and advancing the second endoscope so that the endoscopic knife assembly having a hook blade moves distal to and is in contact with a target tissue at the operation site; operatively engaging the target tissue with the endoscopic knife assembly having a hook blade while withdrawing the latter back towards the cannula under direct visualization through the second endoscope so as to perform an operative procedure on the target tissue; withdrawing the second endoscope and the endoscopic knife assembly having a hook blade from the cannula; withdrawing the cannula through the entry portal; and suturing the incision.
• In one embodiment, the first endoscope and the second endoscope are the same endoscope. In another embodiment, the first endoscope and the second endoscope are different endoscopes.
• The cannula can be inserted into the tissue through a small opening and advanced to a surgical site, thus forming a passageway towards the surgical site. The passageway allows the insertion of the endoscope and endoscopic knife assembly having a hook blade to the surgical site without further damages to the surrounding tissues. The endoscopic knife assembly having a hook blade and a slotted cannula can be used in endoscopic surgical procedures such as carpal tunnel release, cubital tunnel release, plantar fascia release, lateral release for patella realignment, release of the extensor tendons for lateral epicondylitis (tennis elbow), release of the posterior and other compartments of the leg, and the forearm fascial release for fascial compartment syndrome.
• The contents of all references, patents and published patent applications cited throughout this application, as well as the Figures and Tables are incorporated herein by reference.
• The above description is for the purpose of teaching the person of ordinary skill in the art how to practice the present invention, and it is not intended to detail all those obvious modifications and variations of it which will become apparent to the skilled worker upon reading the description. It is intended, however, that all such obvious modifications and variations be included within the scope of the present invention, which is defined by the following claims. The claims are intended to cover the claimed components and steps in any sequence which is effective to meet the objectives there intended, unless the context specifically indicates the contrary.

Claims (28)

1. A hook blade for an endoscopic knife assembly, comprising:

an arm having a forward edge, a trailing edge and an upper cutting surface located on the trailing edge;

a main body having an upper edge, a lower edge, a distal section, a proximate section, and a lower cutting surface located on the upper edge of the distal section;

wherein the distal section of the main body angles downward from the proximate section of the main body, forming a downward angle with the proximate section of the main body,

wherein the arm protrudes from the distal section of the main body and extends back towards the main body in a hook-like manner, forming a hook angle with the proximate section of the main body, and

wherein the upper cutting surface and the lower cutting surface meets at a crotch forming a cutting angle between the two cutting surfaces.

2. The hook blade ofclaim 1, wherein the hook angle is between about 55 degrees and about 75 degrees.

3. The hook blade ofclaim 2, wherein the hook angle is about 65 degrees.

4. The hook blade ofclaim 1, wherein the cutting angle is between about 40 degrees and about 60 degrees.

5. The hook blade ofclaim 4, wherein the cutting angle is about 50 degrees.

6. The hook blade ofclaim 1, wherein the downward angle is between about 150 degrees and about 175 degrees.

7. The hook blade ofclaim 6, wherein the downward angle is between about 165 degrees.

8. The hook blade ofclaim 1, wherein the proximate section of the main body has a tapered end.

9. The hook blade ofclaim 1, wherein the main body comprises a notch on the lower edge to engage with a knife tube.

10. The hook blade ofclaim 1, wherein the arm comprises an upper radius on the upper end of the forward edge to prevent the forward edge from damaging tissue as the hook blade is advanced from a cannula.

11. The hook blade ofclaim 10, wherein the arm further comprises a lower radius on the lower end of the forward edge to prevent the forward edge from damaging tissue as the hook blade is advanced from a cannula.

12. The hook blade ofclaim 1, wherein the hook blade has a total vertical height in the range of about 4 mm to about 5 mm.

13. An endoscopic knife assembly, comprising:

a knife tube having a distal end and a proximate end;

a hook blade attached to the distal end; and

an alignment ring attached near the proximate end,

wherein the hook blade comprises an arm having a forward edge, a trailing edge and an upper cutting surface located on the trailing edge; a main body having an upper edge, a lower edge, a distal section, a proximate section, and a lower cutting surface located on the upper edge of the distal section; wherein the distal section of the main body angles downward from the proximate section of the main body, forming a downward angle with the proximate section of the main body, wherein the arm protrudes from the distal section of the main body and extends back towards the main body in a hook-like manner, forming a hook angle with the proximate section of the main body, and wherein the upper cutting surface and the lower cutting surface meets at a crotch forming a cutting angle between the two cutting surfaces.

14. The endoscopic knife assembly ofclaim 13, wherein the knife tube comprises one or more slots at the proximate end for the attachment of a locking assembly to the knife tube and alignment ring.

15. The endoscopic knife assembly ofclaim 13, wherein the slots are located on a plane that is perpendicular to the hook blade attached to the distal end of the knife tube.

16. The endoscopic knife assembly ofclaim 13, wherein the knife tube is marked on the top or side surface with gradations.

17. The endoscopic knife assembly ofclaim 13, wherein the alignment ring comprises a flattened surface that is positioned perpendicular to the hook blade attached to the distal end of the knife tube.

18. The endoscopic knife assembly ofclaim 13, wherein the hook blade is welded to the knife tube.

19. An instrument kit for implementing an endoscopic surgical procedure comprising:

an endoscopic knife assembly comprising a hook blade, a knife tube and an alignment ring, wherein the blade comprises an upper cutting surface located on a trailing edge of an arm and a lower cutting surface located on an upper edge of a main body of the blade, the cutting surfaces meeting at an angle at a crotch; and

a slotted cannula for endoscopic surgical procedures,

wherein the endoscopic knife assembly is insertable into the slotted cannula.

20. The instrument kit ofclaim 19, wherein the main body of the blade comprises a notch on a lower edge of the main body to engage with the knife tube.

21. A method for a performing a operative procedure on a target tissue in a subject, comprising:

establishing an entry portal,

inserting a cannula having open proximal and distal ends,

inserting an endoscope into the cannula, said endoscope comprising an endoscopic knife assembly having a hook blade,

advancing said endoscope so that the hook blade moves distal to and is in contact with the target tissue, and

operatively engaging the target tissue with the hook blade.

22. The method ofclaim 21, wherein said operative procedure is an endoscopic surgical procedure selected from the group consisting of carpal tunnel release, cubital tunnel release, plantar fascia release, lateral release for patella realignment, release of the extensor tendons, release of the posterior and other compartments of the leg, and forearm fascial release.

23. The method ofclaim 21, wherein said method further comprises a step of withdrawing the hook blade back towards the cannula to perform the operative procedure on the target tissue.

24. The method ofclaim 21, wherein said cannula comprises an open slot extending along the length of the cannula.

25. The method ofclaim 21, wherein said inserting of said endoscope comprising an endoscopic knife assembly having a hook blade is preceded by the insertion of another endoscope comprising a means for visualization of the target tissue.

26. The method ofclaim 25, wherein said cannula is a clear cannula.

27. The method ofclaim 26, further comprising visualization of anatomic structures surrounding the cannula.

28. The method ofclaim 21, wherein said establishing an entry portal comprises making an incision.

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