Retractor for surgical applications

Abstract

The invention relates to a retractor (10) comprising two outer retractor blades (20), a central retractor blade (22), and a spreading device (40) to which the central retractor blade is fixed and on which the two outer retractor blades are movably mounted relative to the spreading device. The aim of the invention is to provide a retractor with a large and reliable opening, which is easy to operate, has a compact spreading device, and is suitable for universal use in different surgical applications. This is achieved by means of a retractor comprising a spreading device (40) which can be operated by a single spreading drive (41), by means of which the two outer, adjustable retractor blades are displaced relative to the central, fixed retractor blade and relative to one another such that the distance between a second geometric centre (75) of the retractor blades and a first geometric centre (48) of the spreading device increases continuously during a spreading operation.

Description

[0001] Retractor for surgical applications

[0002] The invention relates to a refractor for surgical applications with two outer retractor blades and a central retractor blade, as well as a spreading device to which the central retractor blade is fixed and to which the two outer retractor blades are movably arranged relative to the spreading device. The invention further relates to a set of retractor blades for a refractor.

[0003] In surgery, refractors are instruments used to keep access to the surgical field open or even to create it in the first place. They are therefore retractors, also called spreaders. Depending on the design, they are used to manually hold a surgical access open, for example by an assistant to the surgeon, or they contain a locking mechanism and are then called "retractors".

[0004] In general, refractors are used in all surgical disciplines. The simplest refractors are based on the scissor principle to separate two retractor blades (see Fig. 1a): In such a refractor 1, two retractor blades are spread apart by a spreading device 3 using a spreading drive 4. Since the ends of scissors move in circular paths, it is not possible to separate the two blades in a plane parallel to each other. Therefore, rack and pinion mechanisms are used in other refractors (see Fig. 1b): In these refractors 1, two retractor blades 2 are opened by a spreading device 3 by adjusting them along a rack and pinion using their holders, again with a spreading drive 4. This allows two blades to be separated in a plane parallel to each other. However, with conventional, simple spreading devices, it is not possible to separate three blades from each other simultaneously.

[0005] If, due to the required access geometry and size, three or four blades must be used for spreading, as is often the case in spinal surgery, a correspondingly modified Caspar retractor is frequently employed, combining the scissor principle with the use of rack and pinion mechanisms, as shown in Fig. 1c. This clearly complicates the retractor 1: The spreading device 3 contains both two scissor arms, each with a blade 2, and a rack and pinion mechanism on which another arm with a blade is moved to open an access in two directions and thus achieve sufficient working space. However, this spreading device also requires two independent spreading drives 4. Opening an access with such a retractor is therefore difficult and may require assistance.

[0006] Even with retractors 1 used in visceral surgery, where three retractor blades 2 are typically employed, as in the Collin abdominal wall retractor (see Fig. 1d), although the three retractor blades 2 can be moved simultaneously with skillful manipulation using different fingers of the surgeon's or assistant's hand, these are nevertheless two parallel movements that can vary considerably from person to person, meaning that the third retractor blade 2 usually needs to be readjusted. Furthermore, with these retractors, the actual spreading mechanism is very close to the wound when open—closer than when closed—and is therefore often perceived as a hindrance during surgery.

[0007] Therefore, it is not possible to manipulate three vertebral blades simultaneously with a single movement using conventional retractors. Furthermore, in modern spinal surgeries, conventional retractors simply obstruct the midline-crossing surgical approaches. For example, the prong of the Williams retractor interferes with the undercutting maneuver, i.e., when operating across to the other side.

[0008] The present invention therefore aims to provide and further develop a refractor of the type mentioned above, which overcomes the aforementioned problems. In particular, it should be designed to provide a sufficiently large and reliable opening while being easy to operate and, especially with regard to its spreading device, compact and unobtrusive. Furthermore, the refractor should be universally applicable for various surgical applications.

[0009] The problem is solved according to the invention by the teaching of the independent claim. Further advantageous embodiments and developments of the invention are set forth in the dependent claims.

[0010] A retractor for surgical applications comprises two outer, adjustable retractor blades and one central, fixed retractor blade. The term "retractor blade" refers to the actual blade, possibly with a specific shape, and its respective mounting structure (i.e., the part that attaches the blade to another part of the retractor). Each blade has a length suitable for the application, also called the blade depth, which represents the length of the portion after curvature that is inserted into the patient. The retractor also includes a spreader. The spreader is the part of the retractor that opens (and closes) the retractor. It may include drive mechanisms, guide structures, and a housing that optionally supports the guide structures.This spreading device also features a first fixation point for the central retractor blade. The two outer, adjustable retractor blades, however, are movably arranged relative to the spreading device. The design of the fixation point for the central, fixed retractor blade on the spreading device, as well as the mounting structure of this central, fixed retractor blade, together with the further design of the retractor described here, determines a minimum distance between the spreading device and the wound.

[0011] The spreading device has a first geometric center of gravity, which is defined by the external shape of the spreading device. For the purposes of this discussion, it is sufficient to imagine this geometric center of gravity as a fixed, centrally located point on the spreading device. In particular, if the spreading device itself does not change its geometric shape during the opening process, the position of the geometric center of gravity of the spreading device will also remain unchanged.

[0012] A unit consisting of the two outer, adjustable retractor blades and the central, fixed retractor blade has a second geometric center of gravity. This is defined by the three ends of the retractor blades, or rather by the triangle formed by these three ends. Since the position of the three retractor blades relative to each other changes during an opening operation (or conversely, during a closing operation), the position of this second geometric center of gravity also changes.

[0013] By definition, the geometric center of gravity of a physical body corresponds to its center of mass, assuming it is made of a homogeneous material, i.e., has the same density throughout. Purely mechanically, it can then be determined (for a homogeneous material) by balancing. However, determining the geometric center of gravity of any physical body can be more complex mathematically: It is determined by identifying all points within the geometric shape of the body, that is, all points within its outer form or boundary.

[0014] The geometric centroid of a triangle - here the triangle formed by the three ends of the two outer adjustable retractor blades and the central fixed retractor blade - is easy to determine: The geometric centroid or area centroid of a triangle is the common intersection point of the three medians of the triangle.

[0015] The spreading device has a spreading drive that enables the spreading process of the refractor to be carried out and the refractor to be closed again. According to the invention, the refractor is characterized in that the spreading device has a single spreading drive by means of which the two outer, adjustable retractor blades are moved relative to the central, fixed retractor blade and relative to each other such that the distance between the second geometric center of gravity of the retractor blades and the first geometric center of gravity of the spreading device continuously increases during a spreading process from a closed state of the refractor to a maximally open state. The spreading drive of the refractor according to the invention has a rotational axis. Preferably, this is the only rotational axis of the spreading drive.In any case, this axis of rotation is the only axis by which the relative movement of the three retractor blades is actively effected during the opening or spreading process: The relative movement of the three retractor blades is achieved solely through a rotational movement around this single axis. This significantly simplifies the spreading process: The surgeon does not need to change the position of their hand during the spreading process to operate various elements of the spreading mechanism, but rather constantly manipulates only this one axis of rotation. Furthermore, this results in a more compact design of the refractor. The likelihood of parts of the refractor interfering with the surgical procedure is thus reduced.

[0016] A tunnel through tissue to access the surgical field is easier to construct with three retractor blades than with two. To achieve a sufficiently large and reliable opening to the surgical site, an adjustment mechanism is proposed. This mechanism involves moving two of the three retractor blades—the two outer ones—relative to each other and to the third, central, fixed retractor blade using a single spreading drive. This single spreading drive operates in such a way that the geometric center of gravity of the spreading device continuously moves further away from the geometric center of gravity of the three retractor blades, and thus also from the center point of the surgical site. This ensures that the spreading device, or parts of it, minimally obstructs the surgeon's work when the retractor is open and the surgical procedure is performed.No readjustment of a retractor blade is necessary: ​​All three retractor blades are opened in a defined manner relative to each other by actuating the single spreading drive.

[0017] A continuous increase in the distance between the two geometric centers of gravity during the spreading process does not necessarily imply linearity: For example, arrangements are possible in which the distance between the two geometric centers of gravity initially increases rapidly, but as the spreading mechanism continues to open the telescope, the resulting increase in the distance between the two geometric centers of gravity is significantly less than at the beginning of the spreading process. In such cases, the spreading device is quickly removed from the surgical site and hardly interferes, even if the surgeon wants or needs to work with a refractor that is not fully spread.

[0018] Particularly preferably, in a refractor according to the invention, each of the two outer, adjustable retractor blades is attached to a rack, each rack having a toothed structure on one side surface. In such a refractor, the spreading device also has a guide structure designed to receive the two racks of the two outer, adjustable retractor blades crossed at a defined angle to each other and to allow lateral movement. The spreading device of such a refractor further includes a gear that is arranged on the axis of rotation of the spreading drive such that it engages simultaneously with the toothed structures of both racks, thereby allowing the racks to be laterally displaced at a constant angle to each other.

[0019] The lateral displacement of the two crossed racks, and thus of the two outer, adjustable retractor blades, relative to each other as well as to the central, fixed retractor blade, which is "firmly anchored" to this intersection point, is therefore carried out at a defined angle by only one mechanism: A gear drives both racks equally: The two racks are simply turned or rotated forward via the gear.

[0020] The two outer, adjustable retractor blades are attached to their respective racks in such a way that the retractor blades themselves do not need to be rotatable against their racks, but can be rigidly connected to them. This is possible because of the special opening and closing mechanism, which ensures that the three retractor blades always open in the same, ideal position relative to each other without requiring realignment of the two outer retractor blades (which in the prior art is achieved, for example, by rotating them on the racks), and without the retractor blades becoming jammed.In such a particularly preferred embodiment, a rigid fixing of the two outer, adjustable retractor blades to their respective racks makes the entire structure of the refractor with its three retractor blades more stable than in refractors according to the prior art, in which a rotation of the retractor blades on the rods is necessary for the correct alignment of the retractor blades to each other.

[0021] As an alternative to this rigid fixation of the two outer, adjustable retractor blades to their respective racks, it is of course also possible for special applications to attach these two retractor blades to their respective racks in a rotatable manner, without thereby affecting the actual opening mechanism of the refractor. In one variant of this alternative embodiment, the retractor blades can be rotated on the racks and fixed in a new position; in another variant of this alternative design, they remain movable during the spreading process.

[0022] In a special embodiment of the refractor according to the invention, the spreading device is configured to set a value of the defined angle in which the two racks of the two outer, adjustable retractor blades are crossed to each other, in a range between greater than 0° and less than 180°, preferably between greater than or equal to 30° and less than or equal to 90° and particularly preferably to 60°.

[0023] “Defined angle”, as used in this description, therefore means that, as an alternative, it may be a non-changeable angle characteristic of the corresponding refractor, which is set at the factory either individually for the customer or as a standard, for example by means of a fixed guide structure.

[0024] In another alternative, this angle is adjustable before the refractor is used, i.e., before the spreading process, and is then not changed during the spreading process. This can be achieved, for example, via a variable guide structure of the spreading device. In a third alternative, the angle is also variable during the spreading process, preferably according to a designated scheme implemented through the shaping of appropriate components.

[0025] Furthermore, it is advantageous if one of the two racks of the two outer, adjustable retractor blades of the refractor according to the invention has a grid structure on its upper side, into which a gripping lever device arranged on the spreading device and facing the grid structure can engage.

[0026] Preferably, this grid structure is designed such that the locking mechanism of the gripping lever prevents the retraction of the opened refractor from slipping back and thus from closing again. This allows the locking effect to be maintained even without continuous external force. However, further opening or expansion is not prevented. This is achieved by appropriately designed grid teeth (e.g., angled on one side and steeply sloping on the other). In this case, the gripping lever can remain engaged in the grid structure during expansion, and the surgeon does not need to take any action. Only when the refractor is to be closed again does the surgeon release the engaged gripping lever by pressing its lever.

[0027] In another embodiment, the pressure of the lever of the gripping lever device can also be adjusted, thus making it possible to block further lateral movement of the racks.

[0028] In a first further advantageous embodiment of the refractor according to the invention, the two racks of the two outer, adjustable retractor blades are straight. This makes the meshing of the gear and the two tooth structures of the racks very simple, since a very regular tooth structure can be formed on the racks for this purpose.

[0029] In another further advantageous embodiment of the refractor according to the invention, the two racks of the two outer, adjustable retractor blades are curved. To guarantee trouble-free meshing of the gear and the two tooth structures of the racks in this case as well, the tooth structures of the curved racks may have different angles of attack in order to maintain a regular pitch of the tooth structures that matches the gear.

[0030] In an advantageous embodiment of a refractor according to the invention, which has curved racks and whose spreading process is realized by the spreading device with a single spreading drive via a gear on the axis of rotation of a spreading drive, the value of the angle in which the two racks cross is variably encoded for each opening state of the refractor during the spreading process by a corresponding individual shaping of the curved racks.

[0031] By appropriately shaping the curved racks, it can be ensured, for example, that the distance between the second geometric center of gravity of the retractor blades and the first geometric center of gravity of the spreading device increases significantly faster at the beginning of the spreading process than later on.

[0032] In a specific embodiment of a refractor according to the invention, the two outer, adjustable retractor blades are displaced relative to the central, fixed retractor blade and to each other during the spreading process such that their ends always form an isosceles triangle with two legs and a base, such that the ratio of the length of the legs to the length of the base remains constant during the spreading process. The ends of the three retractor blades form the vertices of an isosceles triangle, which is enlarged by operating the spreading drive according to the rule of three.

[0033] The guidance of the three retractor blades is thus based simultaneously on geometry and relative movement. In a refractor according to the invention, whose outer adjustable retractor blades are each attached to a straight rack, the two outer, adjustable retractor blades are moved apart parallel to each other, and a straight line defined by the ends of these two retractor blades, along which the ends of the two outer, adjustable retractor blades define a segment, forms the base of the isosceles triangle, is displaced parallel to the third, central, fixed retractor blade. During the opening maneuver of the refractor, the height to the base of the isosceles triangle increases continuously. The parallel displacement of the base occurs at a defined and initially fixed angle between the two legs.

[0034] During the spreading process, access to the surgical site is opened absolutely uniformly in three directions via the single spreading drive. None of the three retractor blades require readjustment.

[0035] A further advantageous embodiment of the refractor according to the invention also includes a holding device for gripping the refractor during manipulation. For this purpose, the spreader of the refractor has a second fixing point for the holding device. Both fixing points are arranged opposite each other on the spreader.

[0036] The holding device preferably has several openings for better gripping, and is particularly preferably designed in the typical form as with "surgical hooks", namely with a loop with an additional offset retaining ring.

[0037] In a particularly preferred embodiment of the refractor according to the invention, the spreading device has a coupling at at least one of the two fixing points for the holding device and for the central retractor blade, with which the holding device and / or the central retractor blade can be fixed, removed, or replaced.

[0038] The holding device, which assists the surgeon during the opening of access to the surgical site by spreading the refractor, but which can be a hindrance during the actual surgical procedure, can therefore be removed during the procedure by means of the coupling at the second fixation point. This creates greater freedom of movement.

[0039] In addition to its spreading function, the central fixed retractor blade also performs other functions: For example, it can determine the final working depth. To achieve this, it can be replaced before engagement using the coupling at the first fixing point with one of the appropriate length or end shape. Simultaneously, the two outer adjustable retractor blades can also be replaced, preferably together with the racks to which these two retractor blades are attached.

[0040] A refractor whose spreading drive has an end piece by means of which the spreading drive can be manipulated, wherein the end piece is preferably arranged on the single axis of rotation, and is particularly preferably designed to be tiltable.

[0041] In a preferred embodiment, the gear is rotatable by means of this end piece. If the end piece is also designed to be tiltable, it can be tilted away during the actual surgical procedure and is therefore less obtrusive and also allows greater freedom of movement.

[0042] In a further particularly advantageous embodiment of the refractor according to the invention, its retractor blades touch each other in the closed state.

[0043] While current techniques, such as spinal surgery, typically involve opening the fascia and then retracting the musculature detached from the spinous processes away from the midline using, for example, a so-called "Langenbeck retractor" to insert a retractor into the resulting gap, the retractor according to the invention accomplishes this in a single step: The retractor according to the invention is inserted directly into the wound. In its closed state, the central, fixed retractor blade acts like a "Langenbeck retractor," and the two outer, adjustable retractor blades immediately begin the spreading process. The retractor according to the invention thus integrates various functions. Therefore, a time-consuming changeover between different instruments is no longer necessary.

[0044] Furthermore, the retractor according to the invention optionally has equal lengths between the two outer, adjustable retractor blades or different lengths between the two outer, adjustable retractor blades and the central, fixed retractor blade, wherein the lengths are preferably continuously or in steps variable between 2 cm and 20 cm, and wherein the retractor blades particularly preferably have a length of 5 cm, 7 cm, or 9 cm. Such a length of the retractor blades (or blade depth) is particularly advantageous for neurosurgical procedures. In dermatology, on the other hand, significantly shorter retractor blades are required, and visceral surgery requires considerably longer retractor blades (or blade depths) – this is generally true, but additional variability is also needed to, for example, access the surgical site in obese patients.

[0045] Due to the interchangeability of both the central fixed retractor blade and the two outer adjustable retractor blades, the refractor according to the invention can be used for all surgical specialties.

[0046] In a preferred embodiment, the outer adjustable retractor blades are replaced together with the supporting corresponding racks to which these retractor blades are attached. Advantageously, variants with racks of different lengths are also available.

[0047] The retractor blades can also be designed differently, depending on the requirements of the surgical approach. In a preferred embodiment, this possibility of different designs and positions of the retractor blade ends relative to each other is achieved by twisting the retractor blades against the supporting racks at the transition from the toothed forceps to the blade during manufacturing. This allows for a particularly effective adaptation to surgical requirements. This particular embodiment is especially suitable, for example, for the transmuscular Wiltse approach in spinal surgery. In a highly preferred embodiment of the retractor according to the invention, it comprises three retractor blades of equal length, preferably with a length of 9 cm, i.e., a length in the upper region that forms an equilateral triangle in cross-section.The angle at which the racks of the two outer, adjustable retractor blades are crossed is 60°. This allows for a particularly effective opening area.

[0048] The refractor according to the invention can also optionally have different end shapes for the leaves, which preferably correspond to one or more of the following shapes:

[0049] = spoon-shaped or shovel-shaped, for example for use in visceral surgery;

[0050] = angled, for example in the form of a hook that rests against the midline (the medullary processes) during spinal surgery;

[0051] = rounded, liver-hook-like;

[0052] = comb-like, fork-shaped, finger-shaped, Y-shaped, heart-shaped;

[0053] = rod-shaped, round or preferably flattened;

[0054] = spatula-shaped, narrow or wide.

[0055] These variations thus accommodate both different surgical depths and different access variations, thereby serving all surgical applications. The retractor can therefore be used in spinal surgery, visceral surgery, and all other surgical specialties: It is sufficient to insert the appropriate retractor blades of the corresponding lengths. An additional advantage is the adjustability of the defined angle at which the two racks of the two outer, adjustable retractor blades intersect.

[0056] Furthermore, the object of the invention is achieved by a retractor blade set for a refractor according to the invention, which comprises the two outer adjustable retractor blades and / or the central, fixed retractor blade in different lengths and / or end shapes. By using a refractor prepared for the standard exchange of all retractor blades or at least the central, fixed retractor blade, with one or more retractor blades of a different length and / or end shape from the retractor blade set, which can be selectively inserted into the refractor, a wide variety of surgical applications can thus be addressed.

[0057] The object of the invention is further solved by a refractor (10) for surgical applications, comprising

[0058] - two outer, adjustable retractor blades (20),

[0059] - a central, fixed retractor blade (22), and

[0060] - a spreading device (40), wherein

[0061] - the spreading device (40) has a first fixing point (62) for the central retractor blade (22), and the two outer, adjustable retractor blades (20) are movably arranged relative to the spreading device (40), characterized in that

[0062] - the spreading device (40) has a single spreading drive (41) by means of which the two outer, adjustable retractor blades (20) are moved to the central, fixed retractor blade (22) and to each other so that their ends (71) always form an isosceles triangle with two legs (80) and a base (82), wherein the ratio of a length of the legs (80) to a length of the base (82) remains constant during a spreading process from a closed state of the refractor (10) to a maximally open state of the refractor.

[0063] Such a refractor can be operated by means of the rack and pinion arrangements described above, which include the holding device and couplings described above, and whose retractor blades can have different lengths and end shapes.

[0064] The object of the invention is also solved by a refractor (10) for surgical applications, comprising - two outer, adjustable retractor blades (20),

[0065] - a central, fixed retractor blade (22), and

[0066] - a spreading device (40), wherein

[0067] - the two outer, adjustable retractor blades (20) are movably arranged to the spreading device (40),

[0068] -each of the two outer, adjustable retractor blades (20) is attached to a rack (30) which has a toothed structure (32) on one side surface (35), and the two racks (30) of the two outer, adjustable retractor blades (20) are either straight or curved.

[0069] - the spreading device (40)

[0070] = has a first fixation point (62) for the central retractor blade (22),

[0071] = has a single spreading drive (41 ) with a rotation axis (42), which preferably represents the only rotation axis of the spreading drive, and by means of the spreading drive (41 ) the two outer, adjustable retractor blades (20) are moved towards the central, fixed retractor blade (22) and against each other,

[0072] = has a guide structure (46) which is designed to accommodate the two racks (30) of the two outer, adjustable retractor blades (20) crossed at a defined angle (84) to each other and each laterally movable, and

[0073] = contains a gear (43) which is arranged on the axis of rotation (42) of the spreading drive (41) such that it engages simultaneously in the tooth structures (32) of both racks (30), and thereby the racks (30) of the two outer adjustable retractor leaves (20) can be moved laterally and simultaneously at the defined angle (84) to each other during a spreading process from a closed state of the refractor (10) to a maximally open state of the refractor (10).

[0074] In such a refractor with straight racks, the two outer, adjustable retractor blades can be moved relative to the central, fixed retractor blade and to each other in such a way that their ends always form an isosceles triangle with two legs and a base, whereby the ratio of the length of the legs to the length of the base remains constant during a spreading process from a closed state of the refractor to a maximally open state of the refractor.

[0075] It may also include the holding device and couplings described above, and its retractor blades may have different lengths and end shapes.

[0076] There are now various possibilities for advantageously developing and refining the teaching of the present invention and / or combining the embodiments described above – as far as possible – with one another. For this purpose, reference should be made, on the one hand, to the claims subordinate to claim 1 and, on the other hand, to the following explanation of the preferred embodiments of the invention with reference to the drawings. In conjunction with the explanation of the preferred embodiments of the invention with reference to the drawings, generally preferred embodiments and further developments of the teaching are also explained. The drawings show:

[0077] - Figures 1a to 1d show various refractors according to the state of the art;

[0078] - Figures 2a and 2b show a first refractor according to the invention in the closed, i.e., not spread-open state from two perspectives;

[0079] - Figures 3a and 3b show the first refractor according to the invention in an open, i.e. spread-out state from two perspectives;

[0080] - Fig. 3c shows the opening principle of the first refractor according to the invention, with Fig. 3d explaining this schematically again;

[0081] - Figs. 4a and 4b show the crossed racks of an embodiment of the first refractor according to the invention;

[0082] - Fig. 5 shows a second refractor according to the invention, the details of which are explained with the enlarged Figs. 5a and 5b;

[0083] - Figs. 6a and 6b show a third refractor according to the invention in a closed and an open, i.e. spread, state;

[0084] - Figures 7a to 7c show a fourth refractor according to the invention in a closed and an open, i.e., spread-out, state; - Figures 8a and 8b show a fifth refractor according to the invention in a closed state;

[0085] - Figs. 9a to 9c show the first, fifth and fourth refractors according to the invention in a closed state in profile from the side;

[0086] - Figs. 10a and 10b show a top view of the first and third refractors according to the invention in an open state;

[0087] - Figs. 11a and 11b show the crossed racks of the third refractor according to the invention in a closed and an open state.

[0088] The various state-of-the-art refractors shown in Figs. 1a to 1d have already been explained above.

[0089] Figures 2a and 2b show a first refractor 10 according to the invention in its closed, i.e., unspread state, from two perspectives. The refractor 10 has three retractor blades 20, 22. The two outer retractor blades 20 are adjustable, while the central retractor blade 22 is fixedly arranged at a first fixing point 62 of a spreading device 40. In the embodiment of the refractor 10 shown here, this fixed retractor blade 22 can be replaced by actuating a clutch 66. Each retractor blade 20, 22 has an actual blade area at the end with a specific end shape 72 of the retractor blade 20, 22 and a rod or mounting structure by means of which the blade is either fixed in the spreading device 40 (like the central retractor blade 22), or is arranged to be movable relative to the spreading device 40 (like the two outer, adjustable retractor blades 20).

[0090] The spreading device 40 can be operated with a single spreading drive 41. This drive allows the two outer, adjustable retractor blades 20 to be moved relative to the central, fixed retractor blade 22 and relative to each other. In the embodiment shown here, the spreading drive 41 has a single axis of rotation 42 for this purpose. An end piece 44 is mounted on this axis, allowing the spreading drive 41 to be manipulated and thus rotated about its axis of rotation 42. The end piece 44 can be raised to spread the refractor 10 during manipulation or tilted to the side during the actual surgical procedure.

[0091] Each of the two outer, adjustable retractor blades 20 of the refractor 10 is attached to a rack 30, which has a toothed structure 32 on one side surface 35. The racks 30 of the two outer, adjustable retractor blades 20 are movably received in the spreading device 40. For this purpose, the spreading device 40 has a guide structure 46. The two racks 30 of the two outer, adjustable retractor blades 20 are crossed in this guide structure at a defined angle 84 to each other and are each movably received laterally.

[0092] The spreading device 40 further contains inside a gear 43, which is arranged on the axis of rotation 42 of the spreading drive 41 such that it engages simultaneously with the tooth structures 32 of both racks 30. Due to its internal arrangement, this is not visible in Figures 2a and 2b and is shown in Figures 4a and 4b. By means of the gear 43, which engages simultaneously with both tooth structures 32 of the racks 30, both racks 30 are simultaneously displaced laterally at the defined angle 84 to each other.

[0093] In the embodiment shown here, the refractor 10 further comprises a holding device 60. The refractor 10 can be securely grasped by this device during manipulation. The spreading device 40 has a second fixing point 64 for attaching the holding device 60. This second fixing point 64 is located at opposite ends of the spreading device 40 compared to the first fixing point 62. Like the first fixing point 62, this second fixing point 64 also has a coupling 66. With the aid of this coupling 66, the holding device 60 can also be fixed, removed, or replaced in this embodiment of the refractor 10 according to the invention.

[0094] Also visible in Fig. 2a is a gripping lever device 54, which is located on the

[0095] The spreading device 40 is arranged and engages in a structure on the upper side 34 of one of the two racks 30 of the two outer, adjustable retractor blades 20. Its principle is explained in more detail in Fig. 5a.

[0096] Figures 3a and 3b show this first refractor according to the invention in an open, i.e. spread-out state from two perspectives.

[0097] In this spread-out state, the grid structure 50 on the top 34 of one of the two racks 30 of the two outer, adjustable retractor blades 20 is now clearly visible.

[0098] While the three retractor blades 20, 22 touch in the closed state of Figures 2a and 2b and are not easily distinguishable from one another, in this spread state of Figures 3a and 3b, the triangle ABC formed by the three retractor blades 20, 22 is now visible. This triangle is formed by the ends 71 ​​of the retractor blades and provides corresponding access to the surgical field. Figure 3a also shows the first geometric center 48 of the spreading device 40, as well as the second geometric center 75 of a unit consisting of the two outer, adjustable retractor blades 20 and the central, fixed retractor blade 22, whose ends 71 ​​form a triangle. The easily determined geometric center 75 of this triangle ABC is intended to determine the distance to the first geometric center 48 of the spreading device 40.The first geometric center of gravity 48 of the spreading device 40 does not change its position, to a first approximation, during the spreading process. At most, this first geometric center of gravity 48 of the spreading device 40 is slightly displaced due to the very slight change in the overall shape of the spreading device 40 caused by the rotation of the end piece 44 of the spreading drive 41 or by the tilting of the end piece 44 away in a favorable manner, which further minimizes any obstruction of access to the surgical site. Since the end piece will be tilted away from the surgical site for these purposes, this will also slightly increase the distance to the second geometric center of gravity 75, which is formed by the ends 71 ​​of the three retractor blades 20, 22. The second geometric center of gravity 75, formed by the ends 71 ​​of the three retractor blades 20, 22, shifts, however, as the retractor blades 20, 22 open (or...Spreading of the refractor 10) further and further away from the first geometric center of gravity 48 of the spreading device 40, as can be imagined and seen in particular in Fig. 3c.

[0099] Fig. 3c further illustrates the opening principle of the first refractor according to the invention: Firstly, it can be seen that the distance between the second center of gravity 75' of triangle A'B'C formed by the three ends of the retractor blades 20, 22 and the first center of gravity 48 of the spreading device 40 is significantly less when the refractor 10 is half-open than the distance between the second center of gravity 75 of triangle ABC formed by the three ends of the retractor blades 20, 22 when the refractor 10 is fully open. It is easy to imagine that, for the first refractor 10 according to the invention shown here, the distance between the first 48 and the second geometric center of gravity 75 increases linearly depending on the displacement of the racks 30 of the two outer adjustable retractor blades 20 during the spreading process.

[0100] The three retractor blades 20, 22 of this first refractor 10 according to the invention form an isosceles triangle ABC with their ends when spread open. Since the retractor blades 20, 22 of the first refractor 10 according to the invention touch each other when closed, which is achieved by a correspondingly shaped mounting structure for the central fixed retractor blade 22 and by a correspondingly shaped mounting structure for the two outer adjustable retractor blades 20, the two legs AC and AB of the isosceles triangle ABC are each parallel to the straight racks 30 to which the two outer adjustable retractor blades 20 are attached. The angle 84 between the legs AC and AB, which is opposite the two base angles of the isosceles triangle, is thus the angle 84 in which the two racks 30 of the outer, adjustable retractor blades 20 also intersect.During the spreading of this first refractor 10 according to the invention with straight racks 30, this angle 84 remains constant, and thus also the ratio of the length of the legs 80 to the length of the base 82 of the isosceles triangle ABC or, in the less spread state, of the isosceles triangle A'B'C. The rule of three applies here:

[0101] AB / CB =Ä 7 B 7 / CB 7 and ÄC / CB = Ä / CB 7 , where AB = ÄC and W = Ä

[0102] For clarity, this is illustrated again in the schematic drawing of Fig. 3d.

[0103] The illustration of this angle 84 on the spreading device 40 as well as the course of the racks 30 is also indicated in Fig. 3b in dotted lines on the spreading device 40.

[0104] Figures 4a and 4b show the crossed racks 30 of the first embodiment of the refractor 10 according to the invention, the description of which, however, also remains valid for the crossed racks of the second, fourth, and fifth embodiments of the refractor according to the invention. These racks 30 each have a tooth structure 32 on a side surface 35, which is located on the inner side of one of the two racks 30 and on the outer side of the other rack 30. A gear 43 engages simultaneously with the tooth structures 32 of both racks 30 and is rotatably mounted on the single axis of rotation 42.

[0105] If the spreading drive 41 of the spreading device 40 is now operated, and thus the gear is rotated on its axis of rotation 42, the racks 30 are moved laterally at the defined angle 84 to each other, and thus the retractor blades 20, 22 are spread apart from each other.

[0106] The grid structure 50 is also clearly visible on the top surface 34 of one of the two racks.

[0107] Fig. 5 shows another refractor 10 according to the invention, the details of which are explained with reference to the enlarged Figs. 5a and 5b. Fig. 5a shows an enlarged view of the gripping lever device 54, which is arranged on the spreading device 40 of the refractor 10 and engages in a grid structure 50 on the upper surface 34 of one of the two racks 30 of the two outer, adjustable retractor blades 20. In this case, the grid structure 50 is designed such that the engagement of the gripping lever device 54 in the grid structure 50 prevents the retraction and thus the reclosing of the spread refractor 10. For this purpose, the grid structure 50 contains grid teeth that are inclined in one direction. Sliding over them is possible in this direction. In the other direction, the grid teeth slope steeply downwards.This causes the gripping lever device 54 to lock between the teeth and maintain a locking effect of the refractor 10 even without continuous external force. However, this does not prevent further opening or spreading. During spreading, the gripping lever device 54 can continuously engage the grid structure 50. The surgeon's hands remain free. When the refractor 10 is to be closed again, the locked gripping lever device 54 is manually released by pressing its lever.

[0108] Fig. 5b, on the other hand, shows an enlarged view of the coupling 66, which is arranged on the spreading device 40 of the refractor 10 at a first fixing point 62 to allow the replacement of the central, fixed retractor blade 22, whose holder is only indicated here. Pressing on this coupling 66 allows the central, fixed retractor blade 22 to be released and removed in order to insert another retractor blade in its place. When the coupling 66 is released, it holds the central, fixed retractor blade 22 securely.

[0109] Figures 6a and 6b show a third refractor 10 according to the invention in a closed and an open, i.e., spread-open, state. This refractor differs from the first and second refractors 10 according to the invention in that the racks 30, to which the two outer adjustable retractor blades 20 are attached, are no longer straight but curved. The retractor blades 20, 22 of this refractor 10 also have a greater length 70 and blade depth, respectively. The end shape 72 of the retractor blades 20, 22, however, is significantly narrower and straight. This refractor 10 can thus open a surgical site that is considerably deeper than for the first and second refractors 10.

[0110] The curved design of the racks 30 results in the ends 71 ​​of the three retractor blades 20, 22 still describing an isosceles triangle during the spreading process, but the angle 84 opens wider for the curved design of the racks 30 shown here as the spreading process progresses. This angle 84 can be adjusted differently over a certain period by changing the shape of the bend.

[0111] However, the principle of the invention, which also applies to the third refractor 10, remains unaffected, namely that the spreading device 40 of this refractor 10 has a single spreading drive 41 by means of which the two outer, adjustable retractor blades 20 are moved relative to the central, fixed retractor blade 22 and relative to each other in such a way that the distance between the second geometric center of gravity 75 of the retractor blades 20, 22 and the first geometric center of gravity 48 of the spreading device 40 continuously increases during a spreading process from a closed state of the refractor 10 to a maximally open state of the refractor 10. Linearity no longer exists in this case.

[0112] Other features already described for Figures 2 to 5, as well as the general functionality, also apply here and are therefore not described again.

[0113] Figures 7a to 7c show a fourth refractor 10 according to the invention in a closed and an open, i.e., spread-out, state. With respect to its opening during the spreading process, it corresponds to the first and second refractors 10 according to the invention. However, it has retractor blades 20, 22 with a similar length 70 and shape 72 as the retractor blades 20, 22 of the third refractor 10 according to the invention.

[0114] Figures 8a and 8b show a fifth refractor 10 according to the invention in a closed state. This refractor also corresponds to the first, second, and fourth refractors 10 according to the invention with respect to its opening during the spreading process. Even though it is not shown open, it is easy to surmise that this retractor 10 can be used for shallow surgical procedures, for example, in dermatology. It should be emphasized that the refractor 10 can be quickly and easily converted for other applications by replacing the central fixed retractor blade 22 by releasing the coupling 66 that holds this retractor blade 22 at the first fixing point 62, and by replacing the two outer adjustable retractor blades 20, most easily in conjunction with the racks 30 to which they are attached.For this purpose, a set of different retractor blades 20, 22, i.e., retractor blades 20, 22 of different lengths 70 and different end shapes 72, is available, which can be individually assembled by the user, i.e., the surgeon.

[0115] In Figs. 9a to 9c, the first, fifth and fourth refractor 10 according to the invention are shown in a closed state in profile from the side: Here, different retractor blade lengths 70 and different end shapes 72 of the retractor blades 20, 22 are clearly visible and comparable;

[0116] Figures 10a and 10b show a top view of the first and third refractors 10 according to the invention in an open state, i.e., a refractor 10 with straight racks 30 and a refractor 10 with curved racks 30, respectively. The differences regarding the area opened up, which is represented by triangle ABC in each case, are clearly visible. While in Figure 10a the first refractor 10 according to the invention, which has a fixed, defined angle 84 at which the two straight racks 30 intersect (in this case, 60°), uniformly enlarges an opened area in the form of an equilateral triangle ABC, the curved racks 30 of the third refractor 10 according to the invention in Figure 10b lead to a progressively wider opening of the angle 84 during the spreading process.

[0117] Figures 11a and 11b show the crossed racks 30 of the third refractor 10 according to the invention, which has curved racks 30 to which the outer adjustable retractor blades 20 are attached, in a closed and an open state in an interior view of the spreading device 40. This clearly shows how, even here – despite the curved racks 30 – a single gear 43 is able to move both racks 30, further supported by the inner guide structure 46 of the spreading device 40, during the spreading process.

[0118] Finally, it should be emphasized that the exemplary embodiments discussed above serve only to describe the claimed teaching and do not limit it to these embodiments. In particular, the embodiments described above could be combined with one another, where possible.

[0119] List of reference signs

[0120] Refractor after the SdT

[0121] Retractor blade after SdT

[0122] Spreader bars according to the SdT

[0123] Spreading device with drive according to the SdT

[0124] Refractor outer, adjustable retractor blade, central, fixed retractor blade

[0125] rack and pinion

[0126] Tooth structure

[0127] Top side (of the rack)

[0128] Side surface (of the rack)

[0129] Spreader device

[0130] Spreader drive

[0131] axis of rotation

[0132] gear

[0133] End piece (for gripping / turning)

[0134] Guide structure (of the spreader)

[0135] First geometric center of gravity (of the outer

[0136] (Shape of the spreading device)

[0137] Grid structure

[0138] Gripping lever device (which engages in a grid)

[0139] Holding device, first fixing point, second fixing point

[0140] coupling

[0141] Length (of the retractor blade)

[0142] End (of the retractor blade)

[0143] End shaping (of the retractor blade) second geometric center of gravity (of the ends of the

[0144] Retractor blades) 80 legs (of an isosceles triangle)

[0145] 82 Base (of an isosceles triangle)

[0146] 84 angles

[0147] A, B, C, vertices of the isosceles triangle

[0148] A', B', C'

Claims

Patent claims 1. Refractor (10) for surgical applications, comprising - two outer, adjustable retractor blades (20), - a central, fixed retractor blade (22), and - a spreading device (40), wherein - the spreading device (40) has a first fixing point (62) for the central retractor blade (22), the two outer, adjustable retractor blades (20) are movably arranged relative to the spreading device (40), and the spreading device (40) has a first geometric center of gravity (48) defined by the outer shape of the spreading device (40), - a unit consisting of the two outer, adjustable retractor blades (20) and the central, fixed retractor blade (22) has a second geometric center of gravity (75) defined by the three ends (71) of the retractor blades (20, 22), characterized in that - the spreading device (40) has a single spreading drive (41) with a rotary axis (42) by means of which the two outer, adjustable retractor blades (20) are moved to the central, fixed retractor blade (22) and to each other solely by a rotational movement about the rotary axis (42) such that the distance between the second geometric center of gravity (75) of the retractor blades (20, 22) and the first geometric center of gravity (48) of the spreading device (40) increases continuously during a spreading process from a closed state of the refractor (10) to a maximally open state of the refractor (10).

2. Refractor (10) according to claim 1, wherein the axis of rotation (42) is the only axis of rotation of the spreader drive.

3. Refractor (10) according to claim 2, in which -each of the two outer, adjustable retractor blades (20) is attached to a rack (30) which each has a tooth structure (32) on a side surface (35), and - the spreading device (40) = has a guide structure (46) which is designed to receive the two racks (30) of the two outer, adjustable retractor blades (20) crossed at a defined angle (84) to each other and each laterally movable, = and furthermore includes a gear (43) which is arranged on the axis of rotation (42) of the spreading drive (41) such that it engages simultaneously in the tooth structures (32) of both racks (30), and thereby the racks (30) can be laterally displaced at the defined angle (84) to each other.

4. Refractor (10) according to claim 3, wherein the spreading device (40) is configured to set a value of the angle (84) in which the two racks (30) of the two outer, adjustable retractor blades (20) are crossed to each other, in a range between > 0° and < 180°, preferably between > 30° and < 90° and particularly preferably to 60°.

5. Refractor (10) according to claim 3 or 4, wherein one of the two racks (30) of the two outer, adjustable retractor blades (20) has a grid structure (50) on its upper side (34) into which a gripping lever device (54) arranged on the spreading device (40) and facing the grid structure (50) can be engaged.

6. Refractor according to one of claims 3 to 5, wherein the two racks (30) of the two outer, adjustable retractor blades (20) are straight.

7. Refractor (10) according to any one of claims 3 to 5, wherein the two racks (30) of the two outer, adjustable retractor blades (20) are curved.

8. Refractor (10) according to claim 7, wherein the value of the defined angle (84) during the spreading process is individually variable by means of an individual shaping of the bending of the racks (30).

9. Refractor according to claims 1 to 6, wherein the two outer, adjustable retractor blades (20) are displaced relative to the central, fixed retractor blade (20) and relative to each other during the spreading process such that their ends (71) always form an isosceles triangle with two legs (80) and a base (82), wherein the ratio of a length of the legs (80) to a length of the base (82) remains constant during the spreading process.

10. Refractor (10) according to one of claims 1 to 9, which further comprises a holding device (60) for gripping the refractor (10) during manipulation thereof, and whose spreading device (40) has a second fixing point (64) for the holding device (60), wherein this (64) and the first fixing point (62) are arranged at opposite ends.

11. Refractor (10) according to one of claims 1 to 10, wherein the spreading device (40) has a coupling (66) at at least one of the two fixing points (62, 64) for the holding device (60) and for the central retractor blade (22), with which the holding device (60) and / or the central retractor blade (22) can be fixed or removed or replaced.

12. Refractor (10) according to one of claims 1 to 11, whose spreading drive (41) has an end piece (44) by means of which the spreading drive (41) can be manipulated, wherein the end piece (44) is preferably designed to be tiltable.

13. Refractor (10) according to one of claims 1 to 12, the retractor blades (20, 22) of which touch each other in the closed state.

14. Refractor (10) according to one of claims 1 to 13, the retractor blades (20, 22) of which have equal lengths (70) to each other or between the two outer, adjustable retractor blades (20) and the central, fixed retractor blade (22) have different lengths (70), wherein the lengths (70) are preferably continuously variable or in steps between 2cm and 20cm, and wherein the retractor blades (20, 22) particularly preferably have a length of 5cm, 7cm or 9cm.

15. Refractor (10) according to one of claims 1 to 14, the retractor blades (20, 22) of which have end shapes (72) which preferably correspond to one or more of the following shapes: = spoon-like, shovel-like, = angled, = rounded, liver-hook-like = comb-like, fork-shaped, finger-shaped, Y-shaped, heart-shaped, = rod-shaped, round or preferably flattened, = spatula-shaped, narrow or wide.

16. Retractor blade set for a refractor (10) according to one of claims 1 to 15, characterized in that it has the two outer adjustable retractor blades (20) and / or the central fixed retractor blade (22) in different lengths (70) and / or end shapes (72).

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