Abstract: A humerus cutting assembly includes a guide frame having an attachment member adapted to be secured to a humerus adjacent to a humeral head. A cutting guide is releasably connected to the guide frame, the cutting guide configured to guide a tool in altering the humeral head. One or more inertial sensor units is on the cutting guide, the inertial sensor unit tracking an orientation of the cutting guide relative to the humerus based on the releasable connection between the cutting guide and the guide frame.

Abstract: A surgical instrument. The surgical instrument comprises a plurality of sensors, and a status module releasably connected to the surgical instrument. The status module comprises a plurality of contacts, a circuit, and a plurality of indicators. Each individual contact is in electrical communication with a different sensor. The circuit is in electrical communication with at least one of the contacts. At least one of the indicators is in electrical communication with the circuit.

Abstract: A surgical instrument includes a handle assembly, an elongated shaft, an end effector, and an evacuation port. The elongated shaft extends distally from the handle assembly and includes an outer wall. The end effector is coupled to a distal portion of the elongated shaft. The evacuation port is configured for fluid communication with a suction device. A portion of the evacuation port is disposed within the outer wall of the elongated shaft.

Abstract: Described herein are cannulated reamer designs and methods. In one embodiment, a reamer comprises a cannulated central body portion, a plurality of cutting legs and outer frame. The cannulated central body portion has an inner wall surface and an opposing outer wall surface defining a thickness and a bone contacting surface and an opposing distal end surface defining a length, the inner wall surface defining a bore about a central longitudinal axis of the cannulated central body portion. The plurality of cutting legs extends outwardly from the cannulated central body portion. The other defines a periphery of the reamer, the outer frame coupled to a lateral end of each of the plurality of cutting legs. The cannulated central body portion has a recess extending entirely through the thickness and only partially though the length.

Abstract: A medical device for delivering an action to an area of a hip joint or its surroundings, inside a human body of a patient, the hip joint comprising a collum femur and a ball shaped caput femur, being the proximal parts of the femoral bone, and an acetabulum, being a bowl shaped part of the pelvic bone, said medical device comprising an elongated member, having a length axis along its elongated distribution, and a first portion having an end being adapted to enter the body of the patient, said first portion of said elongated member having a first portion cross-section area substantially perpendicular to the length axis of the elongated member, said first portion is adapted to pass through a hole in a bone of the patient, the hole having a hole cross-section area, wherein said first portion cross-section area is smaller than said hole cross-section area, the first portion comprising a mounting portion, and a holding member adapted to hold a mechanical element inside the body of said patient, and a mechanical el

Abstract: Disclosed is a Rongeur for surgical use. The disclosed Rongeur has a push button actuator which, upon activation, allows the long parts of the Rongeur to be easily separated for thorough cleaning and sterilization for reuse.

Abstract: Systems and tools are provided for anchoring a ligament or tendon to bone. In one embodiment, a sheath is provided having a first sidewall with proximal and distal ends and a second sidewall with proximal and distal ends. The distal ends of the first and second sidewalls can be coupled to one another by a hinge pin such that the first and second sidewalls pivot relative to one another about the hinge pin. A sheath inserter tool is also provided and it can be configured to couple to the sheath and to advance the expandable sheath, with a tendon disposed therearound, into a bone hole. An expander is also provided for expanding the sheath. In this way, a tendon or ligament is delivered into the bone hole and the sheath and tendon are locked within the bone hole.

Abstract: A rongeur includes a lower member, a footplate, an upper member and an extension. The lower member is elongate along a first longitudinal axis. The footplate extends upwardly from a distal end portion of the lower member. The footplate includes a first cutting element that defines an apex spaced farthest upwardly from the first longitudinal axis. The upper member includes a second cutting element and is movable relative to the lower member. The extension is provided on the footplate and fixed to the footplate. The extension extends away from the first cutting element a maximum distance D1 measured upwardly from the apex and a maximum distance D2 measured laterally from the first cutting element and perpendicular to D1, where D1?D2, and when D1>0 the extension is laterally confined between opposite lateral sides of the footplate above the apex of the first cutting element in an upward direction.

Abstract: A bone cutting assembly includes a manually actuated upper cutting element that carries a plurality of cutting blades configured to cut through frozen bone segments. A lower cutting element supports a bone segment to be cut and can include cutting blades aligned with the cutting blades of the upper cutting assembly. A pivoting linkage or a rack and pinion arrangement can be provided between the upper cutting element and a manually operated handle to provide sufficient mechanical advantage or leverage to allow an operator to manually cut through the bone.

Abstract: An orthopaedic driver handle including a drivetrain having a driving end and a driven end opposite the driving end and defining a longitudinal axis, and a separable housing covering at least a portion of the drivetrain. The separable housing includes a first portion and a second portion separably connected to the first portion such that sliding the first portion relative to the second portion in a direction of the longitudinal axis unlocks the first portion from the second portion.

Abstract: Described herein are cannulated reamer designs and methods. In one embodiment, a reamer comprises a cannulated central body portion, a plurality of cutting legs and outer frame. The cannulated central body portion has an inner wall surface and an opposing outer wall surface defining a thickness and a bone contacting surface and an opposing distal end surface defining a length, the inner wall surface defining a bore about a central longitudinal axis of the cannulated central body portion. The plurality of cutting legs extends outwardly from the cannulated central body portion. The other defines a periphery of the reamer, the outer frame coupled to a lateral end of each of the plurality of cutting legs. The cannulated central body portion has a recess extending entirely through the thickness and only partially though the length from a location along the length above the bone contacting surface and through the opposing distal end surface.

Abstract: Presently disclosed reamer devices include a longitudinally-extending slot formed through a cutter head portion and a portion of a shaft, thereby allowing engagement of the reamer device with a guide pin inserted into a patient's glenoid by passing the guide pin through the slot and into an interior cannula track extending longitudinally through the interior of the shaft and cutter head portion. Presently disclosed reamer devices may be configured to engage the guide pin when the cutter head portion is positioned at a location medial to the patient's humeral head. Presently disclosed systems include such reamer devices and a guide pin, such as a dual diameter guide pin having an enlarged portion and a smaller portion. Dual diameter guide pins may interact with the interior cannula track of the shaft of the reamer device to serve as a depth limit for advancement of the reamer device along the guide pin.

Abstract: A surgical instrument includes a female branch defining in a coupling area a hollow volume including inwardly facing inner coupling surfaces and including a male branch which can be pivoted relative to the female branch at least partly inside the hollow volume about a pivot axis, the male branch defining in the coupling area a guide portion having outwardly facing outer coupling surfaces in which outer coupling recesses are arranged, wherein on the inner coupling surfaces, inner coupling recesses are arranged which extend relative to a longitudinal axis of the surgical instrument in a direction other than that of the outer coupling recesses.

Abstract: A system that can be used in a knee replacement procedure can include a tibial cut guide and an alignment guide. The tibial cut guide can have a first guide portion coupled to and adjustable relative to a second guide portion. The first guide portion can be configured to define a sagittal cut slot and a proximal cut slot. The alignment guide configured for extramedullary mounting to the patient and configured to couple with the second guide portion of the tibial cut guide, the alignment guide having a first mechanism and a second mechanism of differing construction, the first mechanism and the second mechanism are both configured to be actuated to facilitate extension and retraction of the alignment guide to position the tibial cut guide in a desired proximal-distal location relative a tibia of a patient when the tibial cut guide and the alignment guide are assembled together.

Abstract: Systems and apparatuses including a system that can be used in a knee replacement procedure are disclosed. According to one example, the system can include a tibial cut guide and an alignment guide. The tibial cut guide can have a first guide portion coupled to and adjustable relative to a second guide portion. The first guide portion can be configured to define a sagittal cut slot and the second guide portion can be configured to define a proximal cut slot. The alignment guide can be configured for extramedullary mounting to the patient and can be configured to couple with the second guide portion of the tibial cut guide. The alignment guide can have a first mechanism and a second mechanism of differing construction.

Abstract: A self-cleaning tissue removal instrument is disclosed and described herein. The self-cleaning tissue removal instrument generally comprising: a handle operably coupled with a proximal end of a rail portion; a jaw portion operably coupled to a distal end of the rail portion, a longitudinal axis running along the proximal portion to the distal portion of the self-cleaning tissue removal instrument; wherein the jaw portion is moved from an open position to a closed position by operation of the rail portion translating along the longitudinal axis of the self-cleaning tissue removal instrument, and the jaw portion clamps down and removes tissue in the closed position; and a cleaning mechanism operably coupled with the rail portion, whereby the cleaning mechanism disengages any tissue attached to the jaw portion when the jaw portion longitudinally translates to the open position.

Abstract: Disclosed is a Rongeur for surgical use. The disclosed Rongeur has a push button actuator which, upon activation, allows the long parts of the Rongeur to be easily separated for thorough cleaning and sterilization for reuse.

Abstract: A system including a bone punch tool and a needle guide. The bone punch tool can include a support arm having a support arm proximal portion and a support arm distal portion, a pivot arm having a pivot arm proximal portion and a pivot arm distal portion, and an arcuate punch configured to punch through bone. The pivot arm distal portion can be pivotably coupled to the support arm distal portion, such that the pivot arm proximal portion is configured to be moved away from the support arm proximal portion to extend the arcuate punch into a punch position to punch an arcuate hole through bone. The needle guide can be configured to guide a needle through the arcuate hole.

Abstract: An apparatus comprises a medial rail having a plurality of openings through the medial rail for receiving pins, screws or wires. An arm is pivotally mounted to the medial rail. The arm has at least a first track on a first side. A post has a connector slidably mounted to the first track of the arm for movement along the first track. A guide is slidably mounted for movement along the post. The guide has at least one opening through it and at least one pin for engaging a bone of a patient.

Abstract: A facet joint fixation device formed from a flexible wedge shaped implant constructed from a single piece of material. The device is defined by an insert end spaced apart from outer end by first and second side members. Each side support is cut by a series of recesses defining a living hinge therebetween.

Abstract: A microfracture pick having features configured to aid a user in advancing the microfracture pick through bone. The microfracture pick has an elongated member with a proximal end, a distal end, a sharp, optionally angled tip disposed adjacent the distal end of the elongated member, and at least one engaging feature disposed at one or more locations on the elongated member for engaging a complementary feature of a strike instrument. By striking an impact surface of the strike instrument, the user can produce a force that is translated via the elongated member of the microfracture pick through the tip, thereby making penetration of the tip through the bone more effective.

Abstract: Disclosed herein is a tool, a kit, and associated method for transferring a membranous tissue composed of cells derived from a living body. The tool can include a first sheet-like supporting member disposed on one side of the membranous tissue in a wet state, and a second sheet-like supporting member disposed on the other side of the membranous tissue in a wet state. The first supporting member and the second supporting member can be configured to entirely hold the membranous tissue, such that a frictional force between the first supporting member and the membranous tissue is larger than a frictional force between the second supporting member and the membranous tissue.

Abstract: Improved spinal instruments are provided. In particular, the present application relates to an improved rongeur that allows for multiple bites of bone to be performed in a patient before removing the rongeur from the patient. The rongeur includes a lower shaft and an upper shaft slidable relative to the lower shaft. The lower shaft and upper shaft form a jaw mechanism that can take multiple bites of bone, which can be deposited in a storage cavity formed in the upper shaft. To assist in removing the bone from within the storage cavity, an internal plunger mechanism can be provided that is actuated by a finger hold. In addition, at least portions of the upper shaft are detachable from the lower shaft such that the upper shaft can be thoroughly cleaned and re-used if desired.

Abstract: The invention relates to a surgical instrument, in particular a sliding shaft instrument, with a main part, and a moveable part relative thereto, with a handle attached to the main part, comprising a fixed grip and a grip actuating the moveable part, with at least one guide, through which, in relation to the main part, the moveable part is moveable between an initial position and a working position, and with a sliding surface attached to the movable part and pointing towards the main part, the sliding surface being slid along a guide surface attached to the main part and pointing towards the sliding surface, with at least the sliding surface or the guide surface are assigned to each other for the formation of a washable gap.

Abstract: Rongeur and method for removing intervertebral disk tissue from a spinal column of a patient. A pair of bipolar electrodes on an elongated shaft is placed in proximity to the intervertebral disk tissue. Without withdrawing the instrument from the spinal column, the electrodes are activated with a source of RF energy to stiffen the intervertebral disk tissue, a source of saline solution is supplied to the intervertebral disk tissue and the intervertebral disk tissue is grasped with a grasping tool affixed in conjunction with the distal portion of the elongated shaft biting off a portion of the intervertebral disk tissue having been stiffened. The instrument is withdrawn from the spinal column of the patient to remove the portion of the intervertebral disk tissue. The inserting step, the placing, activating, supplying, grasping, and withdrawing steps are repeated until a desired portion of the intervertebral disk tissue has been removed.

Abstract: Instruments and methods that allow for a minimally invasive way to probe, locate, and cut a meniscus during a meniscectomy procedure. The instrument is a single hybrid probe/cutter instrument provided with both probing and cutting means that allow probing and cutting of the meniscus with the same hybrid instrument. A minimally invasive technique for probing and cutting (resecting) a torn area of a meniscus by employing the single, hybrid probing/cutting instrument is also provided. The technique provides a consistently good-quality meniscus with improved cosmetic results, and is simple and easily reproducible, strong, and time-saving for meniscal repairs.

Abstract: A rongeur which functions to act on (or bite) bone while approaching the bone surface from an axial orientation is provided. In one embodiment, a rongeur is provided with a rotatably/pivotally coupled cutting jaw component to cause the cutting jaw to exert force on the bone. The rongeur may include an axially sliding component which provides axial force and actuates a cutting jaw such that it pivots toward a bone surface. Additionally, a lip feature which creates an opposing surface wherein the cutting jaw pivots toward that surface in order to bite the bone may also be provided. The lip feature may act as a shim between dura mater tissue and the inferior surface of a bone. An axial rongeur may be configured to bite and remove bone when placed while under the surface of a patient's skin (e.g. after axially traversing a distance under the skin).

Abstract: A spinal disc preparation tool is provided that includes an elongate shaft having an inner lumen extending therethrough along a longitudinal axis between proximal and distal ends thereof. A lower jaw is located on a distal end of the elongate shaft for receiving tissue and delivering tissue to the inner lumen, and an upper jaw is pivotally movable relative to the lower jaw. The tool can include various features to facilitate removal and/or collection of tissue.

Abstract: An ultrasonic surgical blade has a blade body at a distal end and a shank at a proximal end, the shank being connectable at a proximal end to a source of ultrasonic mechanical vibrations. A sheath surround at least a portion of the shank. The sheath is configured to define a space between an outer surface of the shank and an inner surface of the sheath. The shank is provided with a liquid-conducting channel terminating in at least one outlet at the outer surface of the shank to enable delivery of irrigant to the space between the shank and the sheath for eventual conduction along an outer surface of the blade body.

Abstract: A device for percutaneously excising tissue. In an embodiment, the device comprises an outer tubular. In addition, the device comprises an inner tubular slidingly received within the outer tubular, wherein the inner tubular has a distal end including an upper member and a lower member. Further, the device includes an open position with the distal end fully extended from the outer tubular, and a closed position with the distal end disposed within the outer tubular, wherein the upper member is biased away from the lower member and is disposed at an open angle ?O relative to the lower member when the device is in the opened position.

Abstract: A microfracture pick having features configured to aid a user in advancing the microfracture pick through bone. The microfracture pick has an elongated member with a proximal end, a distal end, a sharp, optionally angled tip disposed adjacent the distal end of the elongated member, and at least one engaging feature disposed at one or more locations on the elongated member for engaging a complementary feature of a strike instrument. By striking an impact surface of the strike instrument, the user can produce a force that is translated via the elongated member of the microfracture pick through the tip, thereby making penetration of the tip through the bone more effective.

Abstract: A device for percutaneously excising tissue. In an embodiment, the device comprises an outer tubular. In addition, the device comprises an inner tubular slidingly received within the outer tubular, wherein the inner tubular has a distal end including an upper member and a lower member. Further, the device includes an open position with the distal end fully extended from the outer tubular, and a closed position with the distal end disposed within the outer tubular, wherein the upper member is biased away from the lower member and is disposed at an open angle ?O relative to the lower member when the device is in the opened position.

Abstract: A single use bone cutter comprised of two concentric cylinders and a series of insert blades or cutter disc is described. The cutter blades or cutter disc is preferably positioned at the distal end of the cutter. The bone cutter also comprises a guide rod that aids in the line of sight when using the cutter device.

Abstract: A Kerrison rongeur employing a shearing/cutting or grasping mechanism, and suited for specific cutting and sampling bone, cartilage and soft tissue. A slideable upper member has on its advancing face a cutting element that moves past an opposing cutting element on a stationary footplate to produce a shearing action of tissue positioned within the jaws. The cutting element of the slideable member may move past the stationary member on the outside in an overbite situation or on the inside in an underbite situation. A hybrid over/underbite jaw is also contemplated along with a guillotine cutting element and a textured grasping element. In operation, the tissue is placed between the jaw and footplate, and the former is advanced towards the latter to cut and/or grasp and remove for a surgical site.

Abstract: Apparatus and methods are used for severing at least a portion of a lateral retinaculum as part of a lateral release procedure. An elongated guide body has a first, smooth side and second, opposing side having a lengthwise track with a groove. A pushrod having a cutting device is insertable into the track such that the cutting device protrudes from the lengthwise groove, thereby enabling a user to move the pushrod and sever a lateral retinaculum using the cutting device. The cutting device may be a sharp blade or an electrocautery. A method of performing a lateral retinacular release may comprise the steps of inserting the elongated guide body under the skin and subcutaneous fat with the second, opposing side facing a lateral retinaculum; inserting the pushrod into the track of the body; and pushing or pulling the pushrod such that the cutting device severs a lateral retinaculum.

Abstract: The invention relates to a medical instrument comprising at least one movable tool element and at least one actuating element which is mounted such as to be pivotal about a pivotal axis and is coupled to the at least one tool element for the purposes of moving the tool element as a result of a pivotal movement of the actuating element, wherein, for the pivotal mounting of the at least one actuating element, there is provided a pivotal bearing comprising a bearing shaft holder and a bearing shaft which is held in the bearing shaft holder in a working position, wherein the at least one actuating element incorporates the bearing shaft or the bearing shaft holder, wherein the bearing shaft holder has an insertion opening and is insertable through the insertion opening into the bearing shaft holder in a direction that is transverse or substantially transverse to the pivotal axis.

Abstract: Tissue modification devices, and particularly very low-profile, yet strong and manipulatable Rongeur devices. In general, these devices are low-profile, with a flat and thin distal end that may be much thinner than it is wide. The distal end includes a cutting window within which one or more blades move to cut tissue. The distal end region and the curved region forming an angle with an elongate rigid body may be sufficiently stiff and rigid so that the distal end can be pushed (or pulled) against a tissue to be cut with sufficient force so that even hard tissue such as bone may be held within the window and cut by the blade(s).

Abstract: A surgical method utilizes a cutting blade having a thickness along a cutting edge of between about 0.0005 inch and about 0.020 inch and preferably between about 0.001 inch and 0.010 inch. The blade is moved in contact with relatively hardly tissues which are disposed adjacent to softer tissues at a surgical site in a patient. The blade is ultrasonically vibrated during the moving of the blade, whereby the hard tissue is cut with a modicum of damage being inflicted on the soft tissue.

Abstract: A cutting device includes a lower jaw extending between a proximal end and a distal end. The distal end terminates with a cavity and a blunt tip. An upper jaw extends between and proximal end a distal end. The upper jaw is configured for translation along the lower jaw. The upper jaw includes a cutting tip configured to cut bone.

Abstract: A mill head for replaceable attachment to a base so as to collectively form a bone mill. The mill head includes: a first opening in which bone stock is introduced into the head; a cutting device that converts the bone stock into bone chips; a second opening through which the bone chips are discharged; and a third opening through which a motor integral with the base is attached to the cutting device. Internal to the mill head are containment rings. The containment rings prevent the discharge of material through the third opening. The containment rings are services the internal component of the mill head on which the cutting device rests.

Abstract: An orthopaedic surgical instrument includes a polymer 4-in-2 cutting instrument having a number of metallic cutting guides secured thereto. An A/P femoral cutting block of the instrument is removably secured to the instrument's chamfer femoral cutting block.

Abstract: A device and method of delivering a medical tool which may be a resector, cutter, probe, or the like, including a memory arm compacted in a small diameter state which expands in a relaxed memory state, is disclosed. Said delivery may include using a hollow sheath to pre-compact or preload a memory blade into a compact position, transferring said compacted memory blade into a cannula, and deploying said memory blade from the distal end of said cannula whereby the memory blade returns to its normal expanded memory state and a deployment nut can be used to control the extension or the withdrawal of the memory arm and blade.

Abstract: Rongeur and method for removing intervertebral disk tissue from a spinal column of a patient. A pair of bipolar electrodes on an elongated shaft is placed in proximity to the intervertebral disk tissue. Without withdrawing the instrument from the spinal column, the electrodes are activated with a source of RF energy to stiffen the intervertebral disk tissue, a source of saline solution is supplied to the intervertebral disk tissue and the intervertebral disk tissue is grasped with a grasping tool affixed in conjunction with the distal portion of the elongated shaft biting off a portion of the intervertebral disk tissue having been stiffened. The instrument is withdrawn from the spinal column of the patient to remove the portion of the intervertebral disk tissue. The inserting step, the placing, activating, supplying, grasping, and withdrawing steps are repeated until a desired portion of the intervertebral disk tissue has been removed.

Abstract: A chisel includes a hammered portion to be hammered which is provided so as to project from a middle or an end of a handle and extend to pass through a portion on an extended line in the direction opposite to the direction of the blade. Even if the chisel is hammered in a state where a tip of the blade thereof is not inserted into a bone, the chisel easily advances in the direction of the blade, thereby reducing a possibility that the blade slides on a surface of the bone.

Abstract: A rongeur is disclosed having a stationary shank and a crossbar slideable relative to the shank with a tongue in crossbar cooperating with a channel in the shank so as to interconnect the shank to the crossbar. At least one gap section is formed in both the shank and the crossbar to gain access to the interior of the rongeur to permit cleaning and lubrication without disassembling and reassembling the rongeur. Multiple gap sections can be placed in the rongeur longitudinally along the shaft and crossbar if desired.

Abstract: A surgical system for performing a surgical procedure includes a machining tool and a stationary tool. The machining tool has a first contact surface having a hardness. The stationary tool has a second contact surface at least partially formed of a magnesium alloy. The second contact surface is biocompatible and bioabsorbable, and has a hardness. The hardness of the first contact surface is greater than the hardness of the second contact surface.

Abstract: The present disclosure relates to devices and methods for creating channels within bone. One method for treating bone generally includes traversing an elongated member through cancellous bone of a vertebral body along a first generally non-linear path and then retracting the elongated member, thereby leaving a generally non-linear channel. The elongated member then is traversed through the cancellous bone along a second generally non-linear path, which second path does not completely coincide with the first path and then retracted along the second generally nonlinear path, thereby leaving a second generally non-linear channel. Optionally, bone filler material is deployed into the channels.

Abstract: A rongeur including a stationary shaft having a length that terminates in a foot plate, a cutting slide slideably coupled with the stationary shaft and terminating in a cutting edge, a breach extending between the foot plate and the cutting edge for receiving human tissue, and handle means for slidably moving the cutting slide longitudinally relative to the shaft member. The cutting slide is provided with a pair of opposing tracking arms arranged about a distal end of the cutting slide and a third tracking arm arranged about the proximal end of the cutting slide. The tracking arms are slidably and detachably received within corresponding tracking slots in the shaft member when the rongeur is in a closed position. The tracking arms are disengaged from the tracking slots by rotating the cutting slide about a pivot axis that extends substantially parallel to the length of the shaft member thereby placing the rongeur in an open position.

Abstract: Various exemplary methods and devices are provided for removing abnormalities from bone. In general, the methods and devices can be used to allow excess bone to be scraped from a bone surface. In an exemplary embodiment, a scraper tool is provided that includes an elongate shaft having a plurality of blades movably disposed therein. The blades can be configured to move as a unit between a retracted configuration, in which the blades can be entirely disposed within the elongate shaft, and an advanced configuration, in which at least a portion of the blades can extend distally from the elongate shaft and/or flare away from one another. A distal portion of each of the blades can have a radius of curvature corresponding to a radius of curvature of the bone to be scraped.

Abstract: An acetabular reaming system is disclosed of the type having a driver and a tool held together by a quick-release coupling mechanism. The tool (10) has a hollow body (12) defining a domed shape with a rotational axis (14), an apex (16) aligned with the axis (14) and a hemispherical wall (18) extending from the apex (16) to an equatorial rim (20) spaced 90 degrees from the axis (14). The rim (20) has an edge (22) visible to the user that indicates the position of the tool (10) relative to the bone. A first plurality of cutting sites (24) is arrayed along the body (12) and a second plurality of cutting sites (28) is arrayed circumferentially along the edge (22). Preferably, the first plurality of cutting sites (24) present raised first teeth (30, 130, 230, 330) having a profile selected from continuous squared (30), continuous rounded (130), discontinuous squared (230) and tongued (330) profiles.