Abstract
Surgical apparatus and blade elements are provided for performing a tissue cutting process to cleave a tissue portion from a main tissue section. The apparatus comprises a reference member (1) having a cavity (3) for holding a tissue portion subject to the tissue cutting process and a blade guiding surface (2), a blade element (100, 200, 370, 470) adapted for slidable engagement with the reference member, such that the blade moves along the guiding surface of the reference member to perform the cutting process, and a biasing mechanism (80, 82, 91, 92, 102, 202) for moving the blade along the guide surface such that a pressure-relieving space is formed between the blade and the tissue section upon cleavage to avoid deviation of the cutting edge from a desired path. The blade elements can have a contact ridge (107) for guiding the blade element along the predetermined path. In some embodiments, the blade element can include a flexible plate member (101) having first and second opposite sides, a cutting edge (103) formed at a first longitudinal end portion of the plate member, and a manipulating block (102) mounted at a second longitudinal end portion of the plate member (101) for applying a biasing force to the plate member to maintain contact between the blade element and the reference member.
Claims
1. Surgical apparatus for performing a tissue cutting process to cleave a tissue portion from a main tissue section comprising: a reference member having a cavity for holding a tissue portion subject to the tissue cutting process and a blade guiding surface, a blade having a cutting edge for cutting the tissue portion to at least partially sever it from the main tissue section, the blade adapted for slidable engagement with the reference member, such that the blade moves along the guiding surface of the reference member to perform the cutting process, and further characterized by a biasing mechanism for moving the blade along the guide surface such that a pressure-relieving space is formed between the blade and the tissue section (e) upon cleavage to avoid deviation of the cutting edge from a desired path.
2. The apparatus of claim 1 wherein the biasing mechanism maintains the blade at an angle () between 1 and 20 relative to a surface of the reference member or, preferably, between 1 and 20, or 2 and 10, or 2 and 6 relative to the reference member surface.
3. The apparatus of claim 1 wherein the biasing mechanism further comprises a bearing, which maintains the blade at an incline relative to a surface of the reference member as the blade is moved along the guide element to create the space between the blade and the tissue section (e) upon cleavage.
4. The apparatus of claim 1 wherein the biasing mechanism further comprises a bent surface on the blade such that the space is formed by the curve of the blade as the blade is moved along the guide element to create the space between the blade and the tissue section upon cleavage.
5. The apparatus of claim 1 wherein the biasing mechanism further comprises a torque mechanism whereby the blade element is flexed by applying a bending moment to the blade element and, optionally, wherein the applied torque at a distal end of the blade is between 10 and 200 grams, or between 30 and 70 grams.
6. The apparatus of claim 1 wherein the blade further comprises a transverse guide-engaging ridge substantially parallel to the blade edge, which is the contact surface for the slidable engagement of the blade with the guide element.
7. The apparatus according to claim 6 wherein the blade is mounted in the surgical apparatus in a flexed state such that the guide-engaging ridge is forced against the guiding surface for defining the movement path in the cutting process.
8. Surgical apparatus according to claim 1, further comprising a driver for driving the blade along the guiding surface in a cutting direction such that the cutting edge leaves the tissue portion and the main tissue section.
9. Surgical apparatus according to claim 8, wherein the driver further comprises an oscillator for transmitting an oscillating movement to the blade, the oscillating movement being directed in a substantial lateral direction in relation to the cutting direction.
10. Surgical apparatus according to claim 1, wherein the cavity has an opening on the same side as the guiding surface and the cavity is arranged for accommodating and/or holding the tissue portion to be removed from the tissue main section in the cutting process, and wherein the reference member further comprises an source of negative pressure for applying reduced pressure to the cavity for holding the tissue portion to be removed in the cutting process and, optionally, wherein at least a portion of the reference member defining the cavity is formed as air permeable structure for applying reduced pressure to the cavity.
11. Surgical apparatus according to claim 1, wherein a surface of the blade facing to the guiding surface is inclined with respect to the guiding surface in the cutting process such that a space is formed between the blade element and a cut surface of the tissue portion to be removed in the cutting process.
12. Surgical apparatus according to claim 1, further comprising a fixing arrangement for at least partially fixing the main tissue section (E) in a predetermined relationship to the reference member.
13. Surgical apparatus according to claim 12, wherein the fixing arrangement comprises a fixing recess for applying a low pressure to a portion of the main tissue section for fixing the main tissue section in relation to the fixing arrangement and/or the reference member.
14. Surgical apparatus according to claim 1, wherein the main tissue section is an eye and the tissue portion to be removed in the cutting process is a portion of a cornea of the eye.
15. A blade for use in a surgical apparatus for cutting tissue along a predetermined path, the blade comprising: a shank plate having first and second opposite sides, a cutting edge formed at a first longitudinal end portion of shank, a contact ridge formed on a first surface of shank plate at a predetermined distance from the cutting edge with respect to a longitudinal direction of the shank plate, wherein the contact ridge is arranged for slidable engagement with a guiding surface formed in the surgical apparatus.
16. The blade of claim 15 wherein the contact ridge of the blade is further adapted to be held in slidable engagement by a biasing mechanism.
17. The blade of claim 15 wherein the Blade is flexible and the biasing mechanism further comprises a manipulating block is adapted to apply a bending moment force to the blade to induce flexure.
18. The blade according to claim 15, wherein the shank plate further comprises: a main section having a first main surface at the first side of the plate and a second main surface at the second side of the plate and a tip section extending from the main section and including the cutting edge.
19. The blade according to claim 18, wherein the main section is formed with a substantially constant thickness between the first main surface and the second main surface.
20. The blade according to claim 15, wherein the tip section is formed by a first taper surface on the first side of the plate and a second taper surface at the second side of the plate, the first and second taper surfaces merging into the cutting edge.
21. The blade according to claim 20, wherein the position of the cutting edge is offset towards the first side of the plate with respect to a symmetry plane defined in the main section between the first and second main surfaces.
22. The blade according to claim 18, wherein a distance of a plane which is oriented parallel to the first main surface of the main section and which includes the cutting edge is less than 40%, preferably less than 30% of the thickness of the main section.
23. The blade according to claim 20, wherein the contact ridge is formed at a transition of the first taper surface and the first main surface.
24. The blade according to claim 23, wherein the contact ridge protrudes from a first taper surface and a first main surface.
25. The blade according to claim 15, wherein a distance between the contact ridge and the cutting edge in the longitudinal direction of the plate member is 5 to 50 micrometers, preferably 20 to 40 micrometers.
26. The blade according to claim 15, wherein a thickness of the main section is 25 to 250 micrometers, preferably 50 to 100 micrometers.
27. The blade according to claim 15, wherein a slidable engagement between a guide surface and the contact ridge is achieved based on a force, which acts between the guiding surface and the contact ridge.
28. The blade according to claim 15, wherein the contact ridge is linear or curved in shape.
29. The blade according to claim 15, wherein the contact ridge is a continuous structure or composed of a plurality of ridge segments.
30. The blade according to claim 17, wherein the manipulating block has an irregular shape, optionally a polygonal shape to fit into a locking polygonal keyhole, to prevent dislodgement of the blade or cutter during use.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0066] FIG. 1 is a schematic perspective view of a prior art rigid reference member microtome.
[0067] FIG. 1A is a schematic cross-sectional view of an initial stage of a tissue-cutting procedure with a prior art microtome such as shown in FIG. 1.
[0068] FIG. 1B is a schematic cross-sectional view of a subsequent stage of the operation of the prior art microtome of FIG. 1A, illustrating the potential drift of the blade from the desired path due to pressure build-up in the cavity of the reference member.
[0069] FIG. 2 is a schematic illustration of one embodiment of a surgical apparatus according to the invention in which a bearing applies a biasing force to maintain at an angle relative to cutting path to provide a pressure-relief space behind the leading edge of the blade as it cleaves the target tissue.
[0070] FIG. 3 is a schematic illustration of another embodiment of a surgical apparatus according to the invention in which the blade has a curved segment to provide the desired pressure-relief space behind the leading edge of the blade.
[0071] FIG. 4 is a schematic illustration of yet another embodiment of a surgical apparatus according to the invention in which a bending torque is applied to a flexible blade such that the cutting edge of the blade is disposed at an angle relative to cutting path to provide the desired pressure-relief space behind the leading edge of the blade.
[0072] FIG. 5 is a schematic illustration showing portions of the blade in greater detail including a contact ridge on the blade;
[0073] FIG. 5A is an enlarge view of the contact ridge of FIG. 5;
[0074] FIG. 5B is a schematic perspective view of the blade of FIGS. 4 and 5;
[0075] FIG. 6 is a schematic illustration showing portions of the blade in more detail;
[0076] FIG. 7 is a schematic perspective view of another embodiment of a blade according to the present invention having a central cut-out;
[0077] FIG. 7A is a schematic top plane view of the blade of FIG. 7;
[0078] FIG. 7B is a schematic perspective view of the blade of FIGS. 7 and 7A;
[0079] FIG. 8A is a schematic side view of another embodiment of the present invention in which the reference member is curved to relieve pressure build-up in the reference member's cavity;
[0080] FIG. 8B is schematic perspective view of the curved reference member embodiment of FIG. 8B;
[0081] FIG. 9 is a schematic, partially cut-away, side view of an ocular surgery apparatus according to the invention having a stationary guide element for holding an eye and a translatory blade and driver element.
[0082] FIG. 10 is a more detailed schematic side view of the apparatus of FIG. 9 also showing an associated eye-fixation suction ring;
[0083] FIG. 11 is a partially cut-away, side view of the apparatus of FIGS. 9 and 10 with the suction ring and drive mechanism removed;
[0084] FIG. 11A is a schematic cross-sectional, side view showing one mechanism for inserting a blade element and mounting block into an apparatus according to the invention;
[0085] FIG. 11B is a schematic cross-sectional, side view showing another mechanism for inserting a blade element and mounting block into an apparatus according to the invention;
[0086] FIG. 12 is another partially cut-away, side view of the apparatus of FIGS. 9 and 10 showing a mechanism for imparting oscillatory motion to the blade of the apparatus;
[0087] FIG. 13 is a schematic, partially cut-away, perspective view of the apparatus of FIGS. 9-12 showing the blade and block assembly inserted into a mating receptor or keyhole within a driver element of the apparatus;
[0088] FIG. 14 is a cut-away, end view of the stationary element of the apparatus of FIGS. 9-13 showing rails for engaging the translatory blade and drive elements of the apparatus;
[0089] FIG. 15A is a schematic, partially cut-away, side view of an eye fixation ring according to one embodiment of the invention; and
[0090] FIG. 15B is a schematic side view of another embodiment of the invention showing a tissue fixation stage in lieu of an eye fixation device.
DETAILED DESCRIPTION
[0091] In the following, embodiments of the present invention are explained based on the drawings. The surgical apparatus will be explained first followed by an explanation of the blade element. It is noted that the present invention concerns the surgical apparatus having the blade element as well as the blade element as independent subject matter. The terms blade and blade element are used interchangeably and generally throughout this description to describe any mechanism capable of cutting, slicing or cleaving.
[0092] However, a general description of a prior art reference member microtome is first warranted. FIG. 1 shows such a surgical apparatus in an exemplary embodiment, which can be applied to a surgery in an eye. In FIG. 1, the eye is shown as example of a main tissue section E from which a part of the cornea as tissue portion e is to be cut or sliced. The surgical apparatus includes a reference member 1 which is shown with a simplified block shape. In the reference member 1, an arrangement for holding the tissue portion e subject to the tissue cutting process is provided. In the present embodiment, the arrangement for holding the tissue portion e is formed as cavity 3. The cavity is formed in the reference member 1 in the side facing towards the main tissue section E. In the prior art embodiment, a part of the tissue main section E, namely the tissue portion e to be removed from the main tissue section E is placed in the cavity 3.
[0093] In order to make sure that the tissue portion e is held in position, the arrangement for holding the tissue portion e can include a system for applying a reduced pressure to the cavity 3. This system for applying a reduced pressure to the cavity 3 can be formed by a porous material in the area of the cavity, which is permeable for air. This permeable structure can be fluidly connected to a vacuum port V1 to which a reduced pressure can be applied. It is noted that the use of porous material is not strictly required as long as a low pressure can act at the tissue portion e for holding the same in place. In particular, it is possible to provide one or multiple openings in the surface defining the cavity 3 which are in fluid connection with the vacuum port V1. As alternative or in addition to the system using the reduced pressure, adhesive can be used to hold the tissue portion e in the desired location. Although the apparatus and methods of the present invention are generally illustrated for use in refractive correction of a live eye, it should be clear that the invention can also be used on other tissue. Additionally, the invention can used to remove lamella from donor eyes or donor cornea. In such applications the tissue suction ring would simply be replaced by appropriate staging to ensure that the tissue is presented to the blade in a fixed position.
[0094] The reference member 1 includes a guiding surface 2 that is formed on the side of the reference member 1 facing towards the main tissue section E. In the present embodiment, the guiding surface 2 is formed as surface in the reference member, which surface provides a guiding function for the blade element 100. The surface forming the guiding surface 2 can be provided in the peripheral area of the cavity 3. The surface of the guide 2 can be formed as straight surface or alternatively the surface can be designed with a specific curvature or predetermined shape in order to provide a desired guiding path for guiding the blade element 100.
[0095] It is also possible to provide multiple surfaces forming the guide 2 which are for example arranged laterally on opposing sides of the reference member 1 with the cavity been located in between. In any case, the one or multiple surfaces forming the guiding surface are provided in order to extend along a path in which the blade element 7 is to be guided upon performing the cutting process explained below.
[0096] As additional measure for securing the position of the main tissue section E as well as the tissue portion e, a fixing arrangement 4 for at least partially fixing the main tissue section E can e.g. in the form of a suction ring be proved. In the present embodiment, with the application of the surgical apparatus to a surgery in an eye, the fixing arrangement 4 comprises a member in which a fixing recess 5 is provided. In the present example, the fixing recess 5 is formed as annular depression in the radial inner surface of the member having the fixing recess 5. A reduced pressure can be applied to the fixing recess 5 in a similar manner as explained in relation to the cavity 3 above. In particular, a porous arrangement can be provided in the fixing arrangement 4 that is in fluid connection to a vacuum port V4. In another implementation the fixing arrangement 4 can be design as a so-called vacuum ring made of a dense material (e.g., metal or plastic, having a vacuum port directly connected to tissue. When the tissue is corneal tissue, the viscoelastic properties of the eye and the intraocular pressure can be employed to ensure fixation when negative pressure is applied to the ring. When applying the surgical apparatus to a surgery in an eye, a portion of the main tissue section E can be held by applying a reduced pressure in the fixing recess 5 while the portion of the main tissue section E to be held in position is arranged in contact to the fixing arrangement 4. The vacuum port V4 transmits the reduced pressure to the portion of the main tissue section E such that a deformation can takes place and this portion of tissue is held at the fixing arrangement 4.
[0097] The fixing arrangement 4 can be arranged with a constant relationship to the reference member 1. As alternative, the positional relationship between the fixing arrangement 4 and the reference member 1 can be adapted to the specific application. In this case, a specific arrangement can be provided for controlling the positional relationship between the reference member 1 and the fixing arrangement 4. This arrangement can include a manually operated arrangement or can make use of actuators that can be controlled by a system control optionally provided.
[0098] FIGS. 1A and 1B illustrate the problem sometimes encountered with prior art rigid reference member (RRM) microtomes, namely that the cutting process can be affected by a build-up of pressure within the cavity 3 of the reference member 1 as the blade 7 is drawn along the desired path 8 defined by the guiding surface 6 of the reference member 1.
[0099] As shown in FIG. 1B, build-up pressure (hydrostatic pressure) forces the blade 7 away from firm contact with the guiding surface 6 of the reference members. As a result, particularly in the final stages of a cut, a deviation 9 from an ideal resection is sometimes observed.
[0100] FIG. 2 illustrates one embodiment of a surgical apparatus 10 of the present invention, in which the reference member 1 presents a guiding surface 6 like that shown and described in FIG. 1but the blade 70 is biased at angle relative to the guiding surface 6 of the reference member by a bearing mechanism 80. As the blade 70 is driven along the guiding surface 6 by motor 90, the cutting edge 73 is forced into contact with the guiding surface 6 so that blade will slice tissue within cavity 3 along the desired path 8 and not deviate from path 8 due to hydrostatic pressure build-up within the cavity or any other causes. The angle between the blade 70 behind the cutting edge 73 forms a space P that permits expansion of the severed tissue and consequent relief of pressure build-up.
[0101] In FIG. 3 another embodiment of a surgical apparatus 10 of the invention is shown, in which a reference member 1 again presents a guiding surface 6 like that shown and described in FIGS. 1 and 2but the blade 70A is the biased by a bend or curve 72 in the blade itself between the cutting edge 73 and shank 84 of the blade 70A. The bend 72 in the blade 70A provides a pressure relief space P that accommodates expansion of the resected tissue behind cutting edge 73 and the blade 70A is drawn along the desired path 8 by driver 90 such that any pressure that could force the cutting edge of the blade from the guiding edge of the reference member is alleviated/.
[0102] FIG. 4 illustrates yet another embodiment of the surgical apparatus 10 including the above-described RRM elements as well as a flexible blade 100 and a manipulating block 102. The manipulating block 102 can be mounted in a specified arrangement, e.g., via fulcrum 82, for applying desired forces and movements to the plate member 101 of the blade 100 in a predetermined manner. In particular, the blade 100 is mounted to the surgical apparatus such that the plate member 101 is bent or flexed in a predetermined manner, while contacting the guiding surface of the reference member 1 which comprises the surface forming the guiding surface 2. For this reason, a predetermined bending moment is applied. Moreover, a movement of the blade 100, in particular, of the manipulating block 102 can be induced such that the blade 100 can be moved in a direction substantially aligned to guiding surface. An additional arrangement for applying an oscillating movement to the blade 100, e.g., to the manipulating block 102, in the orthogonal direction can be provided to provide a cleaner cut.
[0103] FIG. 4 shows the surgical apparatus in a situation in which the main tissue section E is held by the fixing arrangement 4, wherein the tissue portion e to be removed in the cutting process is placed in the cavity 3. In preparation of the cutting process, the blade 100 is mounted in the surgical apparatus in the way discussed above. Prior to the performance of the operation, the relationship of the surface of the guiding surface 2 and the blade 100 is as shown in FIG. 4. In particular, due to a bending moment applied by the manipulating member 102 to the plate member 101 about Z, the plate member 101 is flexed to a predetermined extent.
[0104] In this situation, which is shown in FIG. 5, the cutting edge 103 is spaced from the surface forming the guiding surface 2 by a cutting edge distance S. Moreover, the contact ridge 107 is in sliding contact to the surface forming the guiding surface 2 with a predetermined pressure created as counterforce in the direction of arrow Y due to the bending or flexing of the plate member 101. A space P as rear space is formed in the area between the guiding surface and the first main surface in of the blade 100 which space is located opposite to the cutting edge 103 in relation to the contact ridge. As shown in FIG. 5, the biasing mechanism maintains the blade (100) at an angle () between 1 and 20 relative to a surface of the reference member or, preferably between 1 and 20, or 2 and 10, or 2 and 6 relative to the reference member surface. In the situation shown in FIG. 4, the operation can be initiated.
[0105] In order to perform the intended cutting operation, which includes a cutting or slicing action to at least partially remove the tissue portion e from the main tissue section E, the blade 100 is moved from the position shown in FIG. 4 towards the tissue portion e. In order to achieve this, the blade is moved by applying a predetermined movement to the manipulating member 102 along the surface forming the guiding surface 2. In specific cases, the surface can be plane or straight as shown in FIG. 4. As indicated above, it is also possible to provide curved or otherwise shaped surfaces, which form a guiding edge 2.
[0106] Optionally, oscillating movement along the direction orthogonal to the direction of blade movement can be applied to the manipulating member 102. For promoting the cutting process, the blade 100 is moved towards the tissue portion e and driven into the tissue with the cutting edge 103. The cutting edge 103 separates the tissue portion e at least partially from the main tissue section E. The optional oscillating movement along the direction of arrow Z enhances the cutting process due to the fact that the cutting edge is oscillated in a direction that is substantially aligned to the direction in which the cutting edge 103 extends.
[0107] While the blade 100 is moved into the tissue, the bending moment applied to the plate member 101 by the manipulating member 102 is maintained such that the contact ridge 107 or the blade 100 is kept in pressure contact in the direction of arrow Y to the surface forming the guiding surface 2. In the course of moving the cutting edge 103 into the tissue, an expansion of the tissue portion e can occur such that the volume of the tissue portion e can become greater than the volume of the cavity 3 in which the tissue portion e is held. The space P shown in FIG. 5, which is provided in the arrangement according to the present invention can accommodate such expansion such that fiction, pressure-induced deviation of the cutting edge, or any other disturbance in the course of the cutting process can be avoided. On the other hand, a space Q forming a front space between the first taper surface 112 and the surface of the guiding surface 2 is very small due to the short distances D2 and S as discussed above.
[0108] Returning to FIG. 4, the movement of the blade 100 into the tissue is continued until the tissue portion e is separated from the main tissue section E to the desired extent. In a specific application, the tissue portion e is to be separated from the main tissue section E completely such that the movement of the blade 100 is continued to an extent that the cutting edge 103 completely sweeps the cavity 3 and completely removes the tissue portion e from the main tissue section E.
[0109] In this situation, the tissue portion e can be maintained in the cavity 3 due to the applied reduced pressure and/or adhesive as explained above. In this situation, the cutting or slicing process is completed and the blade 100 can be retracted. As alternative, the fixing arrangement 4, e.g. the suction ring, can be controlled in position in relation to the reference member such that the main tissue section E is spaced from the separated tissue portion e.
[0110] According to the concept of the present invention, the blade 100 is designed with a specific arrangement, which allows a space P being provided for accommodating an expansion of tissue in the course of the cutting process. Moreover, the specific inventive geometry of the blade increases the accuracy of the position of the cutting edge with respect to the intended cutting surface even with deviating operational conditions. In the inventive surgical apparatus, only a single surface is required for guiding the blade with a satisfactory accuracy. As such, the invention relates to the specific design of the blade 100 as discussed above, while the surgical apparatus contributes to the inventive solution stated above.
[0111] The blade element 100 of the present invention will be explained further with reference to FIG. 6, which illustrates an example of the blade 100 in a schematic view. (The terms blade, blade member and blade element are used interchangeably throughout this description.) The blade 100 is formed by a plate shaped plate member 101, which is in the present embodiment formed as flat rectangular member. The rectangular member can be manufactured by a single piece of metal sheet, e.g. spring steel or the like, providing a specific flexibility. In particular, the plate member 101 can be bent due to its elasticity such that the longitudinal dimension of the plate member 101 follows a bending line.
[0112] Again with reference to FIG. 6, at a first longitudinal end portion of the plate member 101, a tip section 104, 105 is provided. The tip section 104, 105 extends from a main section 106 of the plate member 101. The main section 106 of the plate member 101 covers a major longitudinal portion of the plate member 101. As shown in the drawings, the tip section includes a front tip section 104 and a rear tip section 105. The first longitudinal end portion of the plate member 101 is also provided with a cutting edge 103 which is formed by a sharpened tip end which serves as cutter used in the cutting process. The sharpened tip end can be machined in a known manner.
[0113] A manipulating member 102 can mounted at a second longitudinal end portion of the plate member 101. The manipulating member 102 has a predetermined shape such as a box shape and is mounted to one of two opposite sides of the plate member 101 in the shown example. The manipulating member 102 can be mounted to the plate member 101 by gluing, welding, riveting, screwing or any other method. The purpose of the manipulating member 102 is to introduce a force to the plate member 101, in particular, a bending moment for bending or flexing the plate member 101 and a force for moving the blade 100 in the surgical apparatus. The manipulating member 102 can be provided with recesses or protrusions for transmitting a force for bending or moving the plate member 101 from a driver (not shown).
[0114] In the tip section 104, taper surfaces 110, 112 are provided on both sides of the plate member 101 as explained below. The tip section 104 is formed by a first taper surface 112 which is inclined with respect to a first main surface in formed in one side of the plate member 101. In particular, the first taper surface 112 can be formed in the side of the plate member 101 at which the manipulating member 102 is arranged. The first taper surface 112 is inclined with a predetermined angle in relation to the first main surface 111. It is noted that the offset of the main section 106 of the blade 100 created by the bent or flexed condition is not reproduced for sake of clarity.
[0115] On the other side opposite to the side where the manipulating member 102 is arranged, a second taper surface 110 is provided. The above mentioned first taper surface 112 and the second taper surface 110 merge in the tip end of the plate member 101 for forming the above discussed cutting edge 103.
[0116] With further reference to FIG. 6, the location of a transition of the first taper surface 112 and the first main surface in of the plate member 101 is spaced at a cutting edge distance Di from the cutting edge 103 in the longitudinal direction of the plate member 101. In this context, the longitudinal direction is defined as the direction aligned to the symmetry axis of the main section 106 of the plate member 101. In this context, in a preferred embodiment, the distance between the first main surface in and a second main surface 114 forming the main section 106 of the plate member 101 is substantially constant throughout the main section 106. As such, the surfaces in and 114 are parallel in relation to each other. As already stated, it is not excluded that the main section 106 comprises deviating parts such as holes and protrusions as long as the majority of the main section 106 fulfils this requirement. For a correct explanation, the distance between the cutting edge 103 and the contact ridge 107 is shown as cutting edge distance (mounted) D2 in FIG. 4 using as basis the longitudinal direction of the movement of the blade 100.
[0117] As can be derived from FIG. 6, the blade 100 is shown in a relaxed state in which the first main surface 111 is substantially flat or plane and the offset plane distance W between the first main surface in and a virtual offset plane 108 which is oriented parallel to the first main surface in of the main section 106 is specifically offset as discussed below.
[0118] In particular, the above mentioned offset plane 108 which is oriented parallel to the first main surface 111 is virtually arranged such that this offset plane 108 meets or includes the cutting edge 103. Due to the specific arrangement of the first taper surface 112 and the second taper surface 110, the position of the offset plane 108 is offset from a symmetry plane or symmetry axis of the main section 106 of the plate member 101. In particular, this offset plane 108 is offset towards the first main surface in such that the offset plane distance W is less than 50 percent of the thickness of the plate member 101 in the main section 106. In the shown embodiment, the distance W is approximately 15 percent of the thickness of the main section 106 of the plate member 101. The extent of offset arrangement can be set as required as long as the distance W is less than 50%, preferably less than 40%.
[0119] A contact ridge 107 is preferably formed at the transition of the first taper surface 112 and the first main surface 111, as best shown in FIG. 5A. The protrusion is formed at the transition between the first taper surface 112 and the first main surface 111. In the present embodiment, the protrusion is formed with a circular shape and extends from both the first taper surface 112 and the first main surface in. Preferably, the contact ridge 107 is formed so as to extend throughout the lateral area of the plate member 101. While the embodiment shows the contact ridge 107 with a specific shape, the invention is not restricted to this shape. Rather, any shape of the contact ridge 107 can be selected as long as it is located in the transition of the first taper surface 112 and the first main surface in. Moreover, it is possible to provide the contact ridge 107 as step formed merely by the transition of the first taper surface 112 and the first main surface in without adding any material of providing any specific shape. Therefore, the contact ridge 107 can also be a line-shapes step created by the different angles of the first taper surface 112 and the first main surface 111 at the transition thereof.
[0120] Returning to FIG. 5, the contact ridge 107 can be provided for contacting a guide in particular a guiding surface 2 of a reference member formed in the surgical apparatus. The guiding surface 2 is shown in FIG. 5, which is in contact with the contact ridge 107 while the plate member 101 is flexed or bent forming a bending line along the longitudinal direction of the plate member 101. In the situation shown in FIG. 5, a force resulting from the plate member 101 being flexed or bent acts between the contact ridge 107 and the guiding surface 2 formed in the surgical apparatus. The force acts for avoiding a departure of the plate member 101 from the guiding surface 2 such that guidance is provided by the above-mentioned force. At the same time, a contact between the guiding surface 2 and the cutting edge 103 is avoided due to the provision of the first taper surface 112 in the tip section of the plate member 101. Moreover, the arrangement is such that a space P between the blade 100 and the guiding surface 2 can be provided in the area located opposite with respect to the contact ridge 107 from the cutting edge 103. Consequently, areas other than the contact ridge 107 are not in contact with the guiding surface 2.
[0121] As consequence, the cutting edge 103 is spaced from the guiding surface 2 as shown in FIG. 5 by a cutting edge distance S. According to the inventive arrangement of the blade 100, the blade 100 is arranged for providing a guidance function by a force exerted from the contact ridge 107, which results from the plate member 101 of the blade 100 being flexed by applying a bending moment to the manipulating block 102. Due to the specific arrangement of the cutting edge 103 with respect to the symmetry plane or symmetry axis of the main section 106 of the plate member 101, a deviation of the cutting edge distance S due to differing or deviating flexing states of the plate member 101 are reduced.
[0122] This surprising advantage is achieved due to the fact that a neutral axis of the main section 106 of the plate member 101 does not correspond to the offset plane 108 which is parallel to the first main surface in and which includes the cutting edge 103. In other words, the offset plane 108 which is parallel to the first main surface in and which includes the cutting edge 103 is offset from the neutral axis of the main section 106 towards the side at which the contact ridge is provided in order to reduce the influence of deviating flexing states of the plate member 101 to the cutting edge distance S between the cutting edge 103 and the guiding surface 2 provided in the surgical apparatus. This effect is achieved by reducing a bending or flexing deviation at the tip section including the cutting edge 103 such that a deviation of the bending line of the plate member 101 has a minimum influence on the bending of the tip section in the range between the contact ridge 107 and the cutting edge 103.
[0123] In the illustrated embodiment, the offset plane distance W is optimally less than 40% of the thickness of the plate member 101 in the main section 106. Even better results are achieved with an offset plane distance W of less than 30% of the thickness of the main section 106, wherein the shown embodiment discloses an offset plane distance W of approximately 15% of the thickness of the main section 106.
[0124] The cutting edge distance D1 in the embodiment (shown in FIG. 6) can be set to a range of 5 to 50 micrometers. The cutting edge distance D1 is preferably 20 to 40 micrometers in order to reach a satisfactory accuracy. The cutting edge distance S (shown in FIG. 5) between the cutting edge 103 and the guiding surface 2 can preferably be in the range of 0.5 and 20 micrometers, more preferably in some applications between 2 and 10 micrometers. The thickness of the main section 106 of the plate member 101 is preferably set to 25 to 250 micrometers. Better results are achievable by setting the thickness of the main section 106 to 50 to 100 micrometers. This arrangement is in particular of advantage in case that spring steel is used as material for forming the plate member 101.
[0125] While the above-explained embodiment relates to a specific shape of both the blade and the surgical apparatus, it is possible to deviate from the above explained arrangement without departing from the concept of the present invention. In particular, the shape of the blade element can be modified as e.g. shown in FIGS. 7A and 7B. While the main features of the modified blade element 200 are the same as explained above, differences in relation to the above explained blade element 100 are specified below.
[0126] The blade element 200 shown in FIG. 7A-7B comprises a cutting edge 203 at one end thereof. In an end portion opposite to the cutting edge 203, a manipulating block 202 is provided. A contact ridge 207 is arranged in the blade element 200 in close relationship to the cutting edge 203 as in the blade element 100. The plate member according to this modification is similar as in the previous explanation except the provision of window 213 which is provided in the main section of the blade element 200. In particular, the plate member is formed by a front continuous section 211a in the area of the cutting edge 203. To this front continuous section 211a, a portion having the window 213 is connected, wherein the window 213 is defined by two leg elements 211b. In the end portion where the manipulating block 202 is arranged, a rear continuous section 211C is arranged.
[0127] The above modification provides alternative properties in relation to the flexibility of the plate member which can advantageously employed in the surgical apparatus. Moreover, the window 213 provides an increase of the space P discussed above such that any disturbance between tissue expanding in the process of cutting can be avoided. Moreover, the visibility of elements to be cut is improved due to the fact that the window 213 allows the user of the apparatus to view e.g. the tissue in the cutting process. The remaining advantages and structures are the same as in the above-explained embodiments.
[0128] In FIGS. 8A and 8B another embodiment 300 is presented, in which the blade 370 is flat, but the reference member 301 has a curved surface 310. The curvature in FIG. 8A is two dimensional only as can be seen in the perspective view (FIG. 8B). This design works in all aspects analogous to the previously described embodiments. (The shape of the reference member's cavity can be modified to achieve the desire shape of the resected tissue section.) The curvature of guide surface 310 can be for example a part of a circle or a part of an ellipse.
[0129] FIG. 9 is a schematic, partially cut-away, side view of an ocular surgery apparatus 10 according to the invention having a stationary (rigid reference member) component 10A for holding an eye E and a translatory assembly 10B that holds blade 100. Translatory motion is enabled by rail slots 91, which engage rails (not shown) within the stationary component 10A.
[0130] FIG. 10 is a more detailed schematic side view of the apparatus 10 of FIG. 9 also showing an associated eye-fixation suction ring 4 and vacuum port V4 coupled to the stationary RRM component 10A. Translatory assembly 10B is partially cut-away to illustrate the blade 100, the blade manipulating block or handle 102, as well as oscillatory pin 93 and a rail slot 91, which form part of the driver 90. The driver 90 provides for oscillatory (in and out of the plane of the figure) and translational (right to left) movements of the blade 100.
[0131] FIG. 11 is a partially cut-away, side view of the apparatus of FIGS. 9 and 10 with the suction ring and drive mechanism removed to further illustrate the rail slot 91 for translational movement and the attachment of the blade to drive head 92. The blade 100 is joined to a manipulating block 102 by fastener 95. The blade and block assembly 94 is removably coupled to drive head 92 via recess 97 and slot 97A which restrains the blade's degrees of freedom. In the illustrated embodiment, the block 102 is non-rectangular in shape (e.g., a four or more-sided polygon) and can only be slid into the driver head 92 sidewise such that its irregular polygonal shape prevents dislodgement except by reverse sideways extraction. Once the blade and block assembly 94 is inserted into the slot 97, oscillatory pin 93 can be engaged within a slot (shown in FIG. 12) in the block 102 to further constrain movement of the blade 100. In the illustrated embodiment, the drive head 92 and rail slot 91 act as the bearing that applies a biasing force to the blade such that it remains in contact with the guiding edge 6 of the rigid reference member 1.
[0132] FIGS. 11A and 11B illustrate two alternative mechanisms for joining blade assembly 100 to the translatory drive head 92. In FIG. 11A the mounting block 102 is inserted into recess 97 and locked in place by oscillatory pin (not shown) in pinhole 93A. In FIG. 11B mounting block 102 is likewise inserted into recess 97 and locked in place by snap-fitting 93B.
[0133] FIG. 12 is another partially cut-away, side view of the apparatus of FIGS. 9-11, showing a mechanism for imparting oscillatory motion to the blade of the apparatus. Eccentric pin 93 of driver 90 engages slot 99 of the blade 102. Rotation of shaft 96 caused pin 93 to move in a circular manner within slot 99, thus causing the block 102 and the blade 100 to oscillate in a direction generally orthogonal to the translatory movement of the blade and block assembly 94 along the guiding edge 6 of the reference member 1. (Because this figure is generally drawn to scale, the curvature of the cavity 3 is largely imperceptible.)
[0134] FIG. 13 is a schematic, partially cut-away, perspective view of the apparatus of FIGS. 9-12 showing the assembly 94 (comprising blade 100 and block 102) inserted into a mating receptor or keyhole 97 within a driver element 90 of the apparatus. Slot walls 97B retrain the blade's mounting block's movement. In this illustration, the blade 100 and block 102 are joined together by fastener 95. The apparatus is positioned to allow blade 100 to be drawn across the guiding surface 2 of the rigid reference member 1 to sever a tissue portion (not shown) within cavity 3 from a main section of tissue (not shown). The tissue to be resected can be held with the cavity 3 by either suction or glue applied to the cavity surface prior to engagement.
[0135] FIG. 14 is a cut-away, front view of the stationary element of the apparatus of FIGS. 9-13 showing rails for engaging the translatory blade and drive elements of the apparatus. This front view shows how the translatory elements of the apparatus accomplish tissue resection. Left and right rails (98A and 98B) within the tissue fixation base 96 are engaged by the walls 98C and 98D of complementary rail slots 91. Docking pin 98E can provide a connection to driver 90 (not shown) for implementing translator motion of the blade assembly. Various mechanisms, can be incorporated into drive 90 (not shown) to effect movement of blade 100 into and out of the plane of the drawing. For example driver 90 can comprise a linear motor. Alternatively, translational movement can be controlled manually.
[0136] FIG. 15A is a schematic, partially cut-away, side view of an eye fixation ring according to one embodiment of the invention. Ring 96 can be configured to surround and engage the sclera of eye E. Fixation is maintains by the application of negative pressure via vacuum port V4. In FIG. 15B another embodiment of the invention is shown utilizing a tissue fixation stage 96A in lieu of the eye fixation device of FIG. 15A. The embodiment of FIG. 15B can be useful, for example, in sculpting donor tissue, such as a corneal donor button DB prior to transplantation.
[0137] While the above explanation has been provided based on the application of the surgical apparatus to an eye surgery, the surgical apparatus as well as the blade element are applicable to a general surgical cutting or slicing process of any type of tissue. In particular, the apparatus can be applied to those types of surgical slicing or cutting processes in which a specific high accuracy is required.
REFERENCE NUMERALS
[0138] [This Section Will be Deleted from Final Application] [0139] 1 REFERENCE MEMBER [0140] 2 GUIDING EDGE OR SURFACE [0141] 3 CAVITY [0142] 4 FIXING ARRANGEMENT (SUCTION RING) [0143] 5 FIXING RECESS [0144] 6 GUIDING SURFACE [0145] 8 DESIRED PATH [0146] 9 DEVIATION FROM DESIRED PATH [0147] 10 SURGICAL APPARATUS [0148] 10A STATIONARY COMPONENT OF APPARATUS 10 (FIG. 9) [0149] 10B TRANSLATORY COMPONENT OF APPARATUS 10 (FIG. 10) [0150] 70 BLADE ELEMENT [0151] 70A BLADE (FIG. 3) [0152] 72 CURVED SEGMENT OF BLADE (FIG. 3) [0153] 73 CUTING EDGE [0154] 80 BIASING MECHANISM (BEARING) [0155] 82 FULCRUM [0156] 84 BLADE SHANK (CURVED) [0157] 90 MOTOR/DRIVER [0158] 91 RAIL SLOT [0159] 92 DRIVE HEAD [0160] 93 OSCILLATORY PIN [0161] 94 BLADE AND BLOCK ASSEMBLY [0162] 95 FASTENER [0163] 96 STATIONARY TISSUE FIXATION BASE [0164] 96A TISSUE FIXATION STAGE [0165] 97 RECESS (KEYHOLE) CONNECTING BLOCK TO DRIVE HEAD [0166] 97A SLOT PORTION OF RECESS 93 [0167] 98A/98B RAILS [0168] 98C/98D RAIL SLOT WALLS [0169] 98E DOCKING PIN [0170] 99 SLOT FOR ECCENTRIC PIN [0171] 100 BLADE [0172] 101 PLATE MEMBER [0173] 102 MANIPULATING MEMBER/HANDLE/BLOCK [0174] 103 CUTTING EDGE [0175] 104 FRONT TIP SECTION [0176] 105 REAR TIP SECTION [0177] 106 MAIN SECTION [0178] 107 CONTACT RIDGE [0179] 108 OFFSET PLANE [0180] 110 SECOND TAPER SURFACE [0181] 111 FIRST MAIN SURFACE [0182] 112 FIRST TAPER SURFACE [0183] 114 SECOND MAIN SURFACE [0184] 200 BLADE ELEMENT [0185] 202 MANIPULATING BLOCK [0186] 203 CUTTING EDGE [0187] 207 CONTACT RIDGE [0188] 211a FRONT CONTINUOUS SECTION [0189] 211b LEG ELEMENT [0190] 211c REAR CONTINUOUS SECTION [0191] 212 MANIPULATING BLOCK [0192] 213 WINDOW [0193] 300 CURVED EMBODIMENT [0194] 301 CURVED REFERENCE MEMBER [0195] 310 CURVED GUIDE SURFACE [0196] 370 BLADE ELEMENT (FIG. 8) [0197] D1 CUTTING EDGE DISTANCE [0198] D2 CUTTING EDGE DISTANCE (MOUNTED) [0199] DB CORNEAL DONOR BUTTON [0200] e TISSUE PORTION TO BE RESECTED [0201] E MAIN TISSUE SECTION [0202] P REAR SPACE [0203] Q FRONT SPACE [0204] S CUTTING EDGE DISTANCE [0205] W OFFSET PLANE DISTANCE [0206] V1 VACUUM PORT [0207] V4 VACUUM PORT
