Surgical rod cutting device

Abstract

Surgical rod cutting device comprising a first housing-shaped device part (2) and a second rotary device part (3), which device parts are mounted relative to each other and are rotatable relative to each other about an axis of rotation, wherein in the first device part (2) a continuous axial opening (5) for receiving a rod (35) to be cut is formed, the longitudinal axis of which is oriented in the direction of the axis of rotation and which has an end-side cutting edge, wherein in the second device part (3) a continuous axial opening (15) for receiving the rod (35) to be cut is formed, the longitudinal axis of which is oriented in the direction of the axis of rotation and which has an end-side cutting edge which is formed opposite the cutting edge of the first device part (2),wherein the opening (5) of the first device part (2) and the opening (15) of the second device part (3) are each arranged with the same eccentricity to the axis of rotation, characterized in that a bushing (18a, 18b) having a cutting edge is interchangeably arranged in at least one of the openings (5, 15) and the at least one bushing (18a, 18b) bears against a shoulder (6, 16) in the through opening (5, 15) and is clamped against the shoulder (6, 16), and the through opening (5) of the first device part (2) and / or the through opening (15) of the second device part (3) has a larger diameter at an axial longitudinal end section (B, E) than at an axial longitudinal center section (A, D), wherein the transition of the axial longitudinal end section (B, E) to the axial longitudinal center section (A, D) is the shoulder (6, 16). trains.

Description

[0001] The present invention relates to a surgical rod cutter. It is suitable and intended for mechanically cutting through surgical rods that are used, for example, to stabilize or fix bones or bone parts and are usually made of high-strength or extremely hard materials such as titanium alloys or cobalt-chromium alloys.

[0002] Devices for mechanically severing surgical rods are well known. They are used to enable surgical staff to cut or sever surgical rods of different diameters and materials in an operating room and during an operation comfortably and without great effort. Known devices are often unergonomic due to their design. In some devices, the actuation takes place via two lever arms with handle elements connected by means of one or more hinges. This is disadvantageous in certain situations, for example when both hands are not free for such an operation. Also, depending on the dimensions and the material of the rod to be severed and the mechanics of the rod cutting device, a relatively high expenditure of force may be required to sever the rod, which forces an operator in the operating theater to do physically strenuous work. In order to keep the separating forces to be exerted within an acceptable range, it is necessary to design correspondingly long lever arms, which makes the device bulky and difficult to handle.

[0003] Another disadvantage of known bar cutting devices can be their limited suitability for reprocessing. Depending on the design, it is; e.g. because of long lever arms, it is necessary that this has to be at least partially dismantled for reprocessing, but is difficult to dismantle. The effort to be made for reprocessing can therefore be high, which is disadvantageous.

[0004] Another disadvantage of known rod cutting devices can be that their cutting edges, which are used to cut the usually very hard surgical rods, quickly become blunt. The result is a mandatory use of high-quality and expensive materials or a reduction in the quality of the cutting or separating edges produced. Reworking the cutting edges is usually not possible or only possible to a limited extent.

[0005] US Pat. No. 5,836,937 discloses a surgical cutting instrument in the manner of a bolt cutter with two cutting jaws which are connected via a lever mechanism with two handles. The lever mechanism and the handles cause such a translation that it is possible to cut through surgical rods manually. A U-shaped guide for the rod to be severed is arranged in the area of ​​the cutting edges, by means of which an injury to bone or tissue when the rod is separated is largely prevented. The device has the disadvantage that it requires two-handed operation and, depending on the material and diameter of the rod to be severed, relatively high operating forces. Remanufacturing appears to be problematic due to the numerous narrow spaces in the area of ​​the transmission mechanism, the lack of possibility for easy disassembly and the long lever arms required to achieve a suitable transmission.

[0006] US Pat. No. 5,988,027 discloses a manually operated surgical rod cutter having a stand, a cutting tool mounted thereon and a handle for operating it. The cutting tool essentially consists of two cylindrical cutting components which are adjacent to one another and have cylinder axes which are aligned with one another. The cutting components are rotatable relative to one another about the respective cylinder axis. The first cutting component is connected to the base and the second cutting component is connected to the handle, so that the cutting components are rotated in relation to one another by pivoting the handle. In the cutting components, bores are formed eccentrically to the respective cylinder axis, in which a rod to be severed is to be arranged. When the rod cutter is actuated, the bores of the two cutting components move relative to one another in accordance with the eccentricity, as a result of which a rod inserted therein is sheared off. The handle is designed to be extendable so that the lever arm used and thus the cutting force exerted can be varied. US Pat. No. 5,261,303 discloses a similar rod cutter, the handle of which is foldable. Although one-handed operation is possible with these rod cutters, this requires the rod cutter to be mounted firmly on a table or the like. Their reprocessing is also problematic for the aforementioned reasons. A simple disassembly is not possible.

[0007] US Pat. No. 6,058,820 discloses a surgical rod cutter with a stand, a handle rotatably arranged thereon and two cutting arms. One cutting arm has its first end pivoted to the base, while the other cutting arm has its first end pivoted to the handle. The two cutting arms are connected at their other end by means of a screw bolt, so that they can be pivoted relative to one another about a common pivot axis. The cutting arms have through openings that form cutting edges and in which a rod to be severed can be inserted. By actuating the handle, the two cutting arms are pivoted towards one another, as a result of which the through-openings are displaced towards one another and a rod inserted therein is sheared off. Because of its design and the numerous narrow spaces between relatively moving parts, this rod cutter is difficult to sterilize. A simple disassembly is not possible.

[0008] US patent US 8,127,454 discloses a surgical rod cutter and a method for determining the length of a piece of rod severed therewith. The rod cutter has two handles, on each end of which a cutting element of a tool head is arranged by means of a polygonal receptacle. The cutting elements are held in place by means of a cap so that they can rotate in relation to one another and each have bores with cutting edges into which a rod to be severed is inserted. The handles are telescopically extendable. The length of the piece to be severed can be precisely determined with the aid of a clip that can be arranged on the rod to be severed. On the downside, this rod cutter requires two-handed operation.

[0009] A tool for cutting through threaded rods is known from US 2008 / 0000091 A1. This has a base on which two cutting plates are rotatable about a common axis relative to each other and relative to the base. The cutting inserts rest against one another and have recesses with cutting edges on their circumference. A threaded rod to be severed is inserted into the recesses. The cutting inserts each have a lever arm with which one cutting insert is articulated on the base and the other cutting insert is articulated on a lever arm which is pivotably mounted on the base. By actuating the lever arm, the cutting inserts are rotated relative to one another, so that the cutting edges are displaced relative to one another and a threaded rod accommodated in the recesses is sheared off. The base is held by another handle. A disadvantage is that the tool requires two-handed operation. Remanufacturing is problematic, if not impossible, due to the numerous narrow spaces in the area of ​​the transmission mechanism and the inserts.

[0010] Proceeding from the prior art described above, the object of the invention is to provide a device with which the process of cutting through, in particular intraoperative cutting, of surgical rods in an operating room is simplified and the effort required for this is reduced. The device should preferably be handy, user-friendly and ergonomic and be prepared, i.e. cleaned (if necessary sterilized), without great effort. Finally, a high quality of the cut edges should preferably be ensured even after a longer period of use.

[0011] The above object is achieved according to the invention by a surgical rod cutting device having the features of patent claim 1 .

[0012] In particular, the object is achieved by a surgical rod cutting device, which has a first device part and a second device part, which device parts are mounted relative to one another and can be rotated relative to one another about an axis of rotation, with a through opening for receiving a rod to be severed being formed in the first device part whose longitudinal axis is oriented in the direction of the axis of rotation and which has a cutting edge at the end, a continuous opening for receiving the rod to be severed being formed in the second part of the device, whose longitudinal axis is oriented in the direction of the axis of rotation and which has a cutting edge at the end which the cutting edge of the first device part is formed opposite, wherein the opening of the first device part and the opening of the second device part are each arranged with the same eccentricity to the axis of rotation, the first device ung part and the second device part are operatively connected to one another by means of teeth and can be positioned relative to one another.

[0013] The object is also achieved by a surgical rod cutting device, which has a first device part and a second device part, which device parts are mounted relative to one another and can be rotated relative to one another about an axis of rotation, with a continuous opening in the first device part for receiving a rod to be severed is formed, the longitudinal axis of which is oriented in the direction of the axis of rotation and which has a cutting edge at the end, wherein a continuous opening for receiving the rod to be severed is formed in the second part of the device, the longitudinal axis of which is oriented in the direction of the axis of rotation and which has a cutting edge at the end, which is formed opposite the cutting edge of the first device part, wherein the opening of the first device part and the opening of the second device part are each arranged with the same eccentricity to the axis of rotation, wherein in at least one of the openings of the first device part and of the second device part, a bushing having the cutting or separating edge is arranged interchangeably. It is of particular advantage if such a socket is arranged in the opening of both the first and the second part of the device.

[0014] In other words, the surgical rod cutting pre-seal according to the invention has a preferably cylindrical housing with an axially extending cylindrical blind bore, in the axial extension of which a first rod receiving through bore is formed, which is axially offset by a certain amount with respect to the central axis of the cylindrical blind bore, i.e. eccentric is placed. Furthermore, the surgical rod cutting device has a shearing / rotary disk with (external) toothed rim, from the center of which a bearing pin extends axially, which is rotatably insertable / inserted into the cylinder blind bore. The bearing journal has an axial second rod receiving through-bore which is placed eccentrically to the bearing journal axis with essentially the same axial offset as the first rod receiving through-bore to the housing longitudinal axis.

[0015] The diameter of both through-holes is essentially the same, so that both rod-receiving through-holes are congruent at a specific relative angular position and the two rod-receiving through-holes increasingly overshear when the turntable rotates relative to the housing.

[0016] A cutting edge or shearing edge, preferably in the form of a (replaceable) insert bushing, is provided on the mutually facing end faces of the bearing journal and the bottom of the cylinder blind bore, which are each inserted into the corresponding rod receiving through bore. Finally, a manually or motor-driven / driven gear wheel is mounted in the housing and is operatively engageable or operative with the ring gear to apply a rotary driving force to the high-ratio turntable.

[0017] The device according to the invention is particularly suitable for cutting through a surgical rod with a low driving force due to the high transmission ratio between ring gear and toothed wheel, which can easily be applied manually.

[0018] In the first and the second device part (housing, turntable), a plurality of openings / through-holes for receiving rods to be severed can be formed, in particular with different diameters, in order to severe rods of different strengths.

[0019] In the device according to the invention, a bushing having the cutting or separating edge can be arranged in an exchangeable manner, in particular in the openings / through bores of the first and / or the second device part, as indicated above. As a result, the bushings can be replaced with new bushings when they are worn out.

[0020] Furthermore, in the device according to the invention, the first device part and the second device part can be operatively connected to one another by means of gearing and can be positioned relative to one another, as a result of which larger transmission ratios can be realized than in known lever arm systems.

[0021] Since in the device according to the invention the openings / through-holes of the first and second device part are each arranged with essentially the same eccentricity to the axis of rotation, it is ensured that the openings / through-holes are congruent in a specific (angular) position of the two device parts relative to one another. i.e. one on top of the other so that a rod can simply be inserted through both openings / through-holes.

[0022] The invention allows the transmission of the cutting, shearing or separating force to the surgical rod to be cut by means of a toothed gear, which achieves several advantages, e.g. that a motor or motor system (with low drive line) can be connected in order to To be able to use the device not only manually, but also driven. A further advantage is that the toothed gear enables a very compact device in comparison with rod cutting devices known from the prior art, in which the necessary separating forces are achieved via the action of long levers. Due to the toothed gear, the gear ratio of the rod cutting device can be easily fixed or even varied without necessarily having an impact on the size of the device, as is the case with a lever gear according to the prior art.

[0023] The device according to the invention requires little space when used in the operating theater and can therefore be used very variably. The forces that have to be used to separate the rod can advantageously be set relatively low by selecting a corresponding transmission. Furthermore, due to its compact design, the device can be cleaned and sterilized in conventional reprocessing facilities. It is of particular advantage that the device according to the invention can be operated with one hand.

[0024] With particular advantage, the cutting sleeve can be a disposable product and is preferably only inserted into the rod cutter for a single use. Nevertheless, multiple use of a cutting bush is possible with the device according to the invention. Inadequate cutting edge quality due to wear is generally avoided with a disposable cutting bush. A constant and high quality of the separating edges of the surgical rod is ensured. Since the cutting bushes are usually replaced after a single use, the tooling costs of the device can be kept low compared to the prior art. For example, it is possible to use cutting bushes of lower material quality without reducing the quality of the cutting surfaces achieved. Cutting bushes made of hard metal or HSS can be used with particular advantage (inexpensive standard parts), while expensive special steels (especially for the cutting edges) are required for devices according to the state of the art in order to ensure sufficient service life and qualitatively satisfactory cut surfaces and edges. Since the bushings of the invention have lower hardness and wear resistance requirements, a greater variety of materials is available and the selection can be made with particular advantage with an emphasis on other properties such as biocompatibility or cost.

[0025] An advantage of a replaceable cutting bush is that it can be removed after use and, if desired, reworked and prepared particularly easily, e.g. can be ground. The cutting bushing preferably has a simple shape, for example it is essentially in the form of a hollow cylinder with a circumferential collar at one end. The cutting or separating edge of the socket is formed at an end opposite the collar. With particular advantage, the end face of the bush on the cutting edge side is aligned at a right angle to the longitudinal axis of the bush and is therefore easy to manufacture and, if necessary, to rework, in particular to grind. The bushing can bear against a shoulder in the continuous opening with its circumferential collar. It is preferably braced against the shoulder, so that simple installation is guaranteed while the position of the cutting bush is precisely defined at the same time. According to one embodiment, the cutting bush is secured and / or positioned in the opening of the first or second device part by means of a screw, in particular a screw that can be actuated by hand. In this way, the cutting bush can be changed easily, quickly, inexpensively and on site in the operating theatre.

[0026] According to one embodiment of the invention, as has already been indicated above, the first device part forms a housing and can in particular have a base for setting up on a suitable base. The standing surface is advantageously designed to be non-slip, for example by means of a corresponding coating or surface structuring. It may alternatively or additionally have one or more suction cups which can be deflated and thus enable the device to be set up in a fixed manner on a smooth surface without being permanently attached. However, the housing can also be designed for permanent attachment to a suitable base, such as a side table or the like. For this purpose, it can have bores, for example, by means of which the device can be screwed tightly to the base.

[0027] According to a further optional embodiment of the device, a bearing, preferably a needle bearing, for absorbing radial forces is arranged / used in the first device part, in particular in its blind hole. The bearing is preferably made of a corrosion-resistant material of sufficiently high strength. According to a preferred embodiment of the invention, the bearing is a dry running bearing which does not require lubrication, which is of particular advantage for medical use. Furthermore, the bearing runs very easily and has only low coefficients of friction, which means that only a small amount of effort is required to operate the device. An example of a particularly advantageous material for the bearing rollers is the material with the (DIN) standard designation 1.4125. This exemplary material enables the complete storage area to be reprocessed without hesitation.

[0028] According to a further preferred embodiment, the teeth are formed on the second device part, preferably in the circumferential direction at least in sections. The gearing can be either internal or external gearing. Preferably, on or in the first part of the device, there is a receptacle for an actuating element or a gear wheel which—when arranged in the receptacle—engages in the toothing. The actuating element can be actuated manually, for example in the form of an actuating key with a gear axle and manual handle, or be connected to a drive motor or drive gear in order to enable motorized actuation of the device.

[0029] With particular advantage, the device can have a locking device which allows rotation of the second device part in only one direction. This preferably essentially consists of a spring-loaded pawl which interacts with the toothing and which allows the second device part to rotate in a first direction of rotation, but prevents it from rotating in the opposite direction. The locking device can be operated and / or unlocked manually.

[0030] At least one flushing passage can be formed in the first device part. This preferably leads from the bearing to a connection, preferably a Luer lock connection, and serves to supply cleaning agents to the interior of the device and in particular to the bearing in a particularly simple manner as part of cleaning and reprocessing (sterilization). Such a device is advantageously particularly easy to clean.

[0031] Overall, the device according to the invention is handy and ergonomic and can be parked in different places. The device is preferably made of the material with the (DIN) standard designation 1.4034 (or X46Cr13).

[0032] Further features and advantages of the present invention result from the following exemplary description of particularly preferred embodiments with reference to the figures. It shows:

[0033] figure 1 a schematic representation of the surgical rod cutting device in a front view,

[0034] figure 2 shows a schematic representation of the device of FIG figure 1 in a sectional view along the line I-I in figure 1,

[0035] figure 3 shows a schematic representation of the device of FIG figure 1 and figure2 in one supervision,

[0036] figure 4 shows a detail of the storage of the device figure 2,

[0037] figure 5 shows a schematic representation of the insertion of a bushing having a cutting, shearing or separating edge into the first device part as a housing,

[0038] figure 6 shows a schematic representation of the insertion of a bushing having a cutting, shearing or separating edge into the second device part,

[0039] figure 7 shows a schematic representation of an insertion of the second device part into the first device part,

[0040] figure 8 shows a schematic representation of an insertion of a surgical rod to be severed into the device and

[0041] figure Figure 9 shows the actuation of the surgical rod cutting device.

[0042] In the figure 1 to figure 3 is a surgical rod cutter 1 shown. It has a body 2 as the first device part / housing and a shearing disk 3 as the second device part. body 2 and shearing disk 3 are made of highly tempered stainless steel, e.g. X46Cr13 (or 1.4034), which on the one hand ensures sufficient strength and on the other hand the possibility of reprocessing, i.e. cleaning and sterilization, of the device without corrosion.

[0043] The base body 2 has an essentially cylindrical shape and is equipped with a non-slip base on its outer casing side 4 designed so that it can be set up stably and securely on a suitable work surface in an operating theatre, e.g. a side table or similar. In the base body 2 is an axial through hole or through hole 5 formed whose longitudinal axis is substantially horizontal when the base body 2 on a horizontal surface 4 stands. The passage opening 5 has a small diameter d (rod socket / bushing socket through hole) at an axial longitudinal center portion A and is reduced to a medium diameter D at an axial longitudinal end portion B 1 flared. At its longitudinal end section C opposite section B, it has a diameter D 2 (Cylinder blind hole) widened. The transition from section B to section A is in the form of a shoulder 6 and the transition from section C to section A in the form of a shoulder 7 educated. Section B is internally threaded 8 Mistake. Section C is used as a bearing seat 9 for a needle bearing 10 educated. On the side of section C opposite section A is the through opening 5 to a cylindrical receptacle 11 for the shearing wheel 3 flared.

[0044] The shearing wheel 3 has a bearing section / bearing journal 12 for the needle bearing 10 on, which is central and perpendicular to the shearing disk 3 from this (in one piece) extends. In a section of its circumference, it is provided with a (circumferential) recess 13 Mistake. In the remaining peripheral section, it has external teeth 14 on. The shearing wheel 3 has a through hole 15 , which in a section D has the diameter d and in a section E the diameter D 1 having. The transition from section D to section E is in the form of a shoulder 16 educated. Section E is internally threaded 17 Mistake. The passage opening 15 is also placed decentrally with a predetermined offset to the central axis of the shearing disk 3 , as will be described in more detail below.

[0045] In the passage opening 5 of the body 2 is a cutting bush 18a arranged / deployed / deployable while in the through hole 15 the shearing disc 3 a (counter)cutting bush 18b is arranged / used / usable. The cutting bushes 18a and 18bare equal parts with a section of diameter d and a step 19a or. 19b of diameter D1, so that their longitudinal section form, as in figure 2 is substantially T-shaped. The cutting bush 18a is by means of a retaining screw 20a that are in the internal thread 8 of the body 2 is screwed in, secured so that her paragraph 19a on the shoulder 6 applied. The cutting bush 18b is by means of a retaining screw 20b that are in the internal thread 17 the shearing disc 3 is screwed in, secured so that her paragraph 19b on the shoulder 16 applied. The cutting bushes 18a and 18b are made of biocompatible hard metal and are designed as single-use components, i.e. intended for single use only.

[0046] The shearing disk 3 is by means of the needle bearing 10 in the body 2 relative to this around the axis of rotation of the needle bearing 10 pivoted. In the figure 2 shows that the bearing seat 9 in section C of the through hole 5 of the body is offset by an eccentricity e relative to the central axis of sections A and B. To the same eccentricity e is the through hole 15 the shearing disc 3 opposite the storage section 12 shifted. in the in figure 2 shown position of the body 2 and shearing disk 3 to each other are the central axes of the sections A, B, D and E - and thus also the central axes of the cutting bushes 18 a and 18b – congruent.

[0047] The needle bearing 10 is on his in figure 2 left side in a recess 21 in the shoulder 7 and on his in figure 2 right side by means of a bearing ring 22 secured. The recess 21 forms the fixed bearing and the bearing ring 22 the loose bearing, as can be seen in particular from the detailed representation of the figure. The bearing ring 22 is secured in the base body, e.g. clamped, screwed or welded. The needle bearing 10 has bearing rollers made of the material KCMO.

[0048] At his in the figure 2 upper right side shows the main body 2 an eyelet or tab 23 on. The eyelet / tab 23 opposite is at the bottom of the shot 11 an indentation / hole 24 formed in which a bearing pin 25 is arranged. This serves as a bearing for an adjusting gear key 26 , which serves as an actuator and with which an operator the rod cutter 1 / the shearing disc 3 can operate. The setting key 26 is in figure 7 in perspective before insertion into the base body 2 and in figure 2 in the main body 2 used condition shown. He has a handle (impeller) 27 , an external toothing 28 and a storage opening 29 on. When inserted, the bearing pin engages 25 into the storage opening 29 one, so the adjusting key 26 at his in figure 2 left free end is guided. On the right side, the guide takes place over the eyelet 23 . The external teeth 28 of the adjusting key 26 stands with the external toothing 14 the shearing disc 3 engaged, so that with a rotary operation of the key 26 by an operator rotation of the shearing disc 3 around the axis of rotation of the needle bearing 10 he follows.

[0049] To prevent the shearing disc from resetting unintentionally 3 in the opposite direction, for example due to the elasticity of the rod to be cut / sheared, the rod cutter has 1 a locking device in the form of a ratchet mechanism with a pawl 30 on (see in particular in figure 1, figure 3 and figure 7). This has two locking arms 31a , b and is by means of a spring 32 into a shearing disk 3locking position biased. One of the locking arms stands - in figure 1 the left locking arm 31a – with the external toothing 14 the shearing disc 3 engaged. About the other locking arm 31b the latch mechanism can be manually released by an operator. Will the shearing disk 3 during a separation process using the setting key 26 turned (into figure 1 anti-clockwise), the ratchet mechanism slips. If rotated in the opposite direction, the locking arm locks 31a through its engagement in the external gearing 14 .

[0050] In a section of the circumference of the shearing disc 3 between the peripheral recess 13 and the external gearing 14 a radial bore is formed, in which a ball pressure piece, which is preloaded by means of a spring (not shown), is formed 32 is arranged. At his in relation to the shearing disk 3 On the radially outward-pointing side, it is part-spherical in shape and engages in a circumferential guide track 34 one that is in the base body 2 is trained. In the guideway 34 is a recess not shown in the figures formed, in which the ball pressure piece 32 in the in figure 2 shown "zero position" audibly engages for an operator, in which the center axes of sections A and D of the through-holes 5 or. 15 cursed. In this "zero position" is an insertion of a rod to be severed 35 into the cutting bushes 18a , b possible.

[0051] In the base body 2 fluid passages not shown in the figures are formed. These are at their opening to the exterior of the body 2 with Luer lock connectors 36 provided and form a fluidic connection to section C of the through-opening 5 of the body 2 . The needle bearing can use these fluid passages 10 flushed with cleaning and sterilization fluids during reprocessing.

[0052] The function of the rod cutter 1 will with reference to the figure 5 to figure 9 explained.

[0053] figure 5 shows the insertion of the cutting bush 18a into the main body 2 . The cutting bush 18a is from the in figure 2 left side into section A of the through hole 5 introduced and there by screwing in the retaining screw 20a into the internal thread 8 against the shoulder 6 pressed and secured. Through the attachment to the shoulder 6 is the location of the cutting, separating or shearing edge of the cutting bush 18a precisely defined.

[0054] figure 6 shows the insertion of the cutting bush 18b into the shearing disk 3 . The cutting bush 18b is from the in figure 2 right side into section D of the through hole 15 introduced and there by screwing in the retaining screw 20b into the internal thread 17 against the shoulder 16 pressed and secured. Through the attachment to the shoulder 16 is the location of the cutting, separating or shearing edge of the cutting bush 18b precisely defined.

[0055] figure 7 shows the insertion of the shearing disk 3 with cutting bush mounted in it 18b and retaining screw 20b into the main body 2 . The shearing wheel 3 becomes the basic body 2 aligned that the circumferential recess 13 in the eyelet area 23 lies. When inserted, the bearing section 12 the shearing disc 3 into the needle bearing 10 inserted until the cutting, separating or shearing edges of the two cutting bushes meet 18a , b are each in the intended end position, e.g. butt against each other or have a small gap between them. The ball pressure piece locks in this position 33 into the guideway 34 a. Below is the setting key 26 into the eyelet provided 23 deployed. With the help of the key 26 becomes the shearing disc3 turned anti-clockwise until the outer ring gear 14 behind the eyelet 23 shifted and thus an axial displacement of the shearing disk 3 blocked. This is possible despite the ratchet mechanism because the peripheral recess 13 in the ratchet area 30 located, not with the external teeth 14 the shearing disc 3 is engaged. The shearing disc 3 is rotated until the in figure 2 shown "zero position" is reached. When this "zero position" is reached, the ball pressure piece engages 33 audibly in the indentation in the guide track 34 on, which indicates to the operator that the "zero position" has been reached.

[0056] This is done in the following figure 8 insertion of the rod to be severed 35 into the rod cutter 1 . The rod 35 can only be inserted in the "zero position" because only in this position of the shearing disc 3 to the body 2 the cutting bushes 18a , b flush.

[0057] figure 9 shows the cutting of the rod 35 by turning the shearing disk further 3 by operating the key 26 . Due to the above-described eccentricities of the needle bearing 10 relative to section A of the through hole 5 , – and thus to the cutting bush 18a - As well as to section D of the through-opening 15 – and thus to the cutting bush 18b – when the shearing disk is turned from the “zero position”, there is a circular movement (revolving movement) of the cutting bush 18b with the radius of twice the eccentricity around the central axis of the needle bearing 10 relative to the cutting bush 18a . Through this relative movement in the cutting bushes 18a and 18b inlaid rod 35 sheared off.

[0058] However, the actuation force for shearing off the inserted rod remains so low that it can easily be applied manually. This is achieved, on the one hand, by the transmission ratio between the adjusting key and the external toothed ring on the shearing disc 3 and on the other hand by the transmission ratio between the rotational path of the shearing disk 3 and the eccentric path of the cutting bushes 18a , b. Reference List 1 bar cutter 2 base body / first fixture part 3 Shear washer / second jig piece 4 floor space 5 through hole 6 shoulder 7 shoulder 8 internal threads 9 bearing seat 10 needle bearings 11 recording for 3 12 storage section 13 recess 14 external teeth 15 through hole 16 shoulder 17 internal thread 18a, b cutting bush 19a, b paragraph 20a,b retaining screw 21 recess 22 bearing ring 23 eyelet 24 deepening 25 bearing pin 26 setting keys 27 handle 28 external toothing of 26 29 warehouse opening 30 pawl 31a,b locking arm 32 spring 33 ball thrust piece 34 guideway 35 staff 36 Luer lock connector QUOTES INCLUDED IN DESCRIPTION

[0059] This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Patent Literature Cited

[0060] US5836937

[0005] U.S.5988027

[0006] US5261303

[0006] US6058820

[0007] U.S.8127454

[0008] U.S. 2008 / 0000091 A1

[0009]

Claims

[1] Surgical rod cutting device comprising a first housing-shaped device part ( 2 ) and a second rotary device part ( 3 ) exhibits which device parts ( 2 , 3 ) are mounted relative to each other and are rotatable about an axis of rotation relative to each other, wherein in the first device part ( 2 ) a continuous axial opening is formed for receiving a rod to be cut, the longitudinal axis of which is oriented in the direction of the axis of rotation and which has an end-side cutting edge and in the second part of the device ( 3 ) a continuous axial opening is formed for receiving the rod to be cut, the longitudinal axis of which is oriented in the direction of the axis of rotation and which has an end-side cutting edge which is formed opposite the cutting edge of the first device part, wherein the opening of the first device part (2 ) and the opening of the second device part ( 3 ) are each arranged with the same eccentricity to the axis of rotation and wherein the first device part ( 2 ) and the second device part ( 3 ) are technically connected to each other by means of a gear system and can be positioned relative to each other. [2] Surgical rod cutting device comprising a first housing-shaped device part ( 2 ) and a second rotary device part ( 3 ) exhibits which device parts are mounted relative to each other and are rotatable about an axis of rotation relative to each other, wherein in the first device part ( 2 ) a continuous axial opening is formed for receiving a rod to be cut, the longitudinal axis of which is oriented in the direction of the axis of rotation and which has an end-side cutting edge, wherein in the second device part ( 3) a continuous axial opening is formed for receiving the rod to be cut, the longitudinal axis of which is oriented in the direction of the axis of rotation and which has an end-side cutting edge that corresponds to the cutting edge of the first device part ( 2 ) is formed oppositely, wherein the opening of the first device part ( 2 ) and the opening of the second device part ( 3 ) are each arranged with the same eccentricity to the axis of rotation, wherein a bushing having the cutting edge, preferably of a disposable type, is arranged in at least one of the openings in a replaceable manner. [3] Surgical rod cutting device for cutting a surgical rod, comprising the features of claims 1 and 2. [4] Surgical rod cutting device according to any one of the preceding claims, characterized by that the first device part ( 2) forms an essentially cylindrical housing, which preferably has a base ( 4 ) for placement on a base. [5] Surgical rod cutting device according to any one of the preceding claims, characterized by that in the through-opening of the first device part ( 2 ) an inner bearing, preferably a needle bearing ( 10 ) is arranged. [6] Surgical rod cutting device according to any one of the preceding claims, characterized by that the second device part ( 3 ) a toothing, preferably internal or external toothing ( 14 ) exhibits a circumferential feature that is at least partially formed. [7] Surgical rod cutting device according to any one of the preceding claims, characterized by that in the first device part ( 2 ) a recording ( 24 ) for one with the toothing ( 14 ) of the second device part ( 3) combing actuator ( 26 ) is trained. [8] Surgical rod cutting device according to one of the preceding claims, further comprising a locking device ( 30 ), preferably in the form of a toothed ( 14 ) cooperating pawl, which prevents a rotation of the second device part ( 3 ) allows rotation in a first direction, but prevents rotation in the opposite direction. [9] Surgical rod cutting device according to any one of claims 5 to 8 above, characterized by that in the first device part ( 2 ) Flushing passages are formed that lead from the bearing to a Luer-Lock connection in order to supply sterilizing agent to the bearing. [10] Surgical rod cutting device according to any one of claims 2 to 9 above, characterized by that at least one socket ( 18a , b) consists of hard metal, preferably biocompatible hard metal. [11] Surgical rod cutting device according to any one of claims 2 to 10 above, characterized by that at least one socket ( 18a , b) rests against a shoulder in the through opening, preferably is braced against the shoulder, in particular by means of a screw element ( 20a , b).

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