Patent Publication Number: US-2021186533-A1

Title: Cutting Guide With Protective Insert

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of the filing date of U.S. Provisional Patent Application No. 62/953,264 filed Dec. 24, 2019, the disclosure of which is hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Different methods and devices have been developed in the past to enable a surgeon to remove bony material to create specifically shaped surfaces in or on a bone for various reasons such as for the attachment of various devices or objects to the bone. As the ultimate goal of any surgical procedure is to restore the body to normal function, it is critical that the quality, location, and orientation of a surgeon&#39;s cut, as well as the quality of the bone at and around the cut are sufficient for achieving proper healing of the body. 
     These aspects of bone resections are critical to the final location and orientation of any implant and thus play a significant role in the success or failure of any surgery or artificial joint. The quality as well as the location and orientation of the resections also directly impact the amount of bony material removed, and solutions that minimize bone loss are optimal. Additionally, with any surgical procedure, time is critical, and methods and devices that can save operating room time, are valuable. Past efforts have had variable success in properly locating and orienting resections in a quick and efficient manner as well as in maintaining the proper location and orientation of the cut during the procedure. 
     Oscillating sawblades used for most resections follow the path of least resistance when cutting through bone and deflect in a manner creating variations in the cut surfaces and contributing to prosthesis mal-alignment as well as poor fit between the prosthesis and the resection surfaces. Patient-specific guides have been developed to attain aspects of these goals. However, such guides have either not allowed for any flexibility for the surgeon from a preoperative plan at the time of a surgical operation or have not provided sufficient control such that resections have been made that deviated from the preoperative plan. 
     Accordingly, still further improvements in the alignment and operation of cutting tools for resecting bone surfaces are desired in order to increase the consistency and repeatability of bone resection procedures as is the improvement of prosthetic stability in attachment to bone. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with an aspect of the present disclosure, a system for guiding a cutting tool in an osteotomy procedure may include a cutting block and an instrument for use with the cutting block. The cutting block may be fixable to bone, such as by pins, and the instrument may be a hand held instrument. The cutting block may include one or more apertures extending from a proximal to a distal side of the cutting block, such that bone to be cut may be accessible from the proximal side of the cutting block through the apertures. The instrument may include a sleeve receivable through the aperture, and the sleeve may be dimensioned to limit the movement, in particular the lateral movement, of a cutting tool, such as a sawblade of an oscillating bone saw as the sawblade is inserted into bone. 
     The one or more apertures may be closely fitted to the sleeve such that motion of the instrument relative to the cutting block when the sleeve is inserted into an aperture is limited to that permitted by withdrawal or further insertion of the sleeve into the aperture. In some arrangements, the one or more apertures may be a single aperture that is not closely fitted to the sleeve. In some arrangements, the instrument may include a tongue receivable in one or more grooves in the cutting block. The one or more grooves may be closely fitted to the tongue such that motion of the instrument relative to the cutting block when the tongue is inserted into a groove is limited to withdrawal or further insertion of the tongue into the aperture. In some arrangements, the shapes of and spacing between the aperture and the one or more grooves may cooperate with the shapes of and the spacing between the tongue and the sleeve such that motion of the instrument relative to the cutting block when the tongue is inserted into a groove is limited to withdrawal or further insertion of the tongue into the aperture. 
     Such limiting of motion of the instrument relative to the cutting block described above with regard to various arrangements may permit the sleeve of the instrument to reliably guide a cutting tool when the instrument is used in cooperation with the cutting block. Cuts resulting from guidance of the cutting tool by the instrument in cooperation with the cutting block may be dictated by features of the cutting block, such as the size and spacing of the one or more apertures and grooves. The cutting block may be constructed according to patient and case specific parameters such that a unique cutting block may be constructed and used for any osteotomy procedure. 
     In another aspect, a system for guiding a cutting tool in an osteotomy procedure may include a cutting block. The cutting block may include an aperture extending through a thickness of the cutting block and having a length and a width, the width of the aperture being defined between a first interior surface of the cutting block and a second interior surface of the cutting block opposing the first interior surface. The system may further include a sleeve. The sleeve may include a slot configured to receive a sawblade and configured for insertion into the aperture of the cutting block such that the sleeve contacts either the first interior surface or the second interior surface without contacting the other interior surface, the slot having a length and a width. 
     In some arrangements, a periphery of the aperture may be defined at least partially by the first and the second interior surfaces of the cutting block. Either one or both of the first and the second interior surfaces may include a flat portion and ribs protruding from the flat portion into the aperture. 
     In some arrangements, a profile of the aperture may be such that the width of the aperture varies along the length of the aperture, and the width of the aperture at a widest point of the aperture may be less than the length of the aperture. 
     In some arrangements, the aperture may have a substantially trapezoidal profile. 
     In some arrangements, a ratio of the width of the slot to a width of the sleeve may be less than 2:3. 
     In some arrangements, a ratio of a maximum length of the slot to a maximum width of the slot may be between 5:1 and 50:1. 
     In some arrangements, a ratio of the length of the sleeve to the length of the aperture may be less than 2:3. 
     In some arrangements, a height of the sleeve may extend along at least 50 percent of a thickness of the cutting block. 
     In some arrangements, the width of the slot may be less than 3 mm. 
     In some arrangements, the instrument may further include a tongue extending from the instrument. In such arrangements, the cutting block may include a groove extending into the cutting block. The groove may be shaped to receive the tongue from a proximal side of the cutting block and may be spaced from the aperture such that the tongue may be received in the groove simultaneously with the sleeve being received in the aperture. 
     In some arrangements, a cross-sectional shape of the groove may match a cross-sectional shape of the tongue such that motion of the instrument relative to the cutting block, while the sleeve is inserted into the aperture and the tongue is inserted into the groove such that the instrument abuts the proximal side of the cutting block, may be limited to a direction corresponding to withdrawal of the tongue from the groove. 
     In some arrangements, the system may further include an oscillating sawblade configured for receipt within the slot such that the sleeve substantially limits lateral movement of the oscillating sawblade to a region defined by the slot. 
     In accordance with another aspect, an osteotomy may be performed according to a process. In such process a cutting block may be secured to bone. The cutting block may include a proximal surface, a distal surface opposite the proximal surface and facing the bone, and an aperture extending from the proximal surface to the distal surface. In such process, an instrument may be positioned adjacent to a first interior surface of the aperture and spaced from a second interior surface of the aperture such that a first portion of a slot extending through the instrument extends within the aperture. The bone may be cut with a cutting tool while the instrument is positioned against the first interior surface of the aperture and the cutting tool is extending through the first portion of the slot such that the slot may limit lateral movement of the cutting tool to a region defined by the slot. 
     In some arrangements, the instrument may be stabilized during the cutting by applying force to a handle of the instrument that extends away from the cutting block. 
     In some arrangements, the instrument may be repositioned to the second interior surface of the cutting block after cutting the bone while the instrument is positioned against the first interior surface. The bone then may be cut along the second interior surface of the cutting block while the instrument is positioned against the second interior surface of the aperture. In some such arrangements, a first tongue of the instrument may be inserted into a first groove of the cutting block to position the instrument against the first interior surface, and the first tongue or a second tongue of the instrument may be inserted into a second groove of the cutting block to position the instrument against the second interior surface. 
     In some arrangements, a tongue of the instrument may be inserted into a groove of the cutting block to position the instrument against the first interior surface. 
     In accordance with another aspect, an osteotomy may be performed according to a process. In such process, a cutting block may be secured to bone. The cutting block may include a proximal surface, a distal surface opposite the proximal surface and facing the bone, and a plurality of apertures extending from the proximal surface to the distal surface. The a slot of an instrument may be positioned within a first aperture of the plurality of apertures. A first portion of the bone may be cut with a cutting tool while the slot of the instrument is positioned within the first aperture and the cutting tool is extending through the slot such that the slot limits lateral movement of the cutting tool to a region defined by the slot. The slot of the instrument may be repositioned within a second aperture of the plurality of apertures after the step of cutting the first portion of the bone. A second portion of the bone may be cut with a cutting tool while the slot of the instrument is positioned within the second aperture and the cutting tool extends through the slot such that the slot limits lateral movement of the cutting tool to the region defined by the slot. 
     In some arrangements, the plurality of apertures may be nonparallel such that surfaces of the bone formed by the cutting steps are nonparallel. 
     In some arrangements, the bone may form part of a foot. 
     In another aspect, a system for guiding a cutting tool, e.g., a surgical oscillating saw, for cutting bone, such as for an osteotomy procedure, may include a cutting block and a tool guiding instrument. The cutting block may have one or more apertures that extend through a thickness of the cutting block. The instrument may include a sleeve that may be sized to accommodate the cutting tool and to extend through at least a portion of the one or more apertures of the cutting block. The cutting block may be constructed based on patient-specific data. In this manner, either one or both of the size and orientation of any one of the one or more apertures may be configured according to the patient-specific data. Further, the cutting block may have one or more surfaces or contours that may be configured according to the patient-specific data. In one such example, the cutting block may have a bone facing surface with a contour constructed according to the patient-specific data so as to match a contour of a corresponding region of bone. 
     Any one of the one or more apertures may be dimensioned to restrain movement of the sleeve when the sleeve is disposed through the aperture so as to limit the possible size, angle, and rotation of a cut that may be made with the cutting tool through the sleeve while the sleeve is disposed through a given aperture. In arrangements in which the cutting block includes multiple apertures, each aperture may correspond to a cut to be made in a surgical procedure. 
     The cutting block may include an aperture large enough to accommodate the sleeve in multiple locations of the aperture. Such a large aperture may have multiple surfaces corresponding to cuts to be made in a surgical procedure. The cutting block and instrument may include further features, other than the aperture and sleeve, that may cooperate to guide the instrument relative to the cutting block such that the sleeve may be disposed through the aperture at only certain discrete locations. The discrete locations may correspond to preoperatively determined cuts to be made in the surgical procedure. In some arrangements, a tongue may extend from the instrument and one or more grooves having a similar shape and size as the tongue to substantially prevent lateral movement of the tongue may extend into the cutting block while, in a reversed configuration in some other arrangements, the instrument may include a groove and one or more tongues. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the subject matter of the present invention and various advantages thereof may be realized by reference to the following detailed description and the accompanying drawings, in which: 
         FIG. 1  is a plan view of a cutting guide system according to an embodiment; 
         FIG. 2  is a cross-sectional view along lines  2 - 2  of  FIG. 1 ; 
         FIGS. 3A and 3B  are perspective views of the cutting guide system of  FIG. 1 ; 
         FIG. 4  is a plan view of a cutting guide system according to another embodiment; 
         FIG. 5  is a cross-sectional view along lines  5 - 5  of  FIG. 4 ; and 
         FIGS. 6A and 6B  are perspective views of the cutting guide system of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     As used herein, the term “proximal,” when used in connection with a surgical tool or device, or components of a device, refers to the end of the device closer to the user of the device when the device is being used as intended. On the other hand, the term “distal,” when used in connection with a surgical tool or device, or components of a device, refers to the end of the device farther away from the user when the device is being used as intended. As used herein, the terms “substantially,” “generally,” “approximately,” and “about” are intended to mean that slight deviations from absolute are included within the scope of the term so modified. 
     Referring to  FIG. 1 , cutting guide system  10  includes instrument  14  and cutting block  34 . Instrument  14  includes a handle  18 , a head  22 , and a neck  20  connecting handle  18  to head  22 . Head  22  includes a slot  26  extending in a direction perpendicular to a length of handle  18 . A sawblade  30 , which in some arrangements may form part of cutting guide system  10 , is shown received in slot  26  and extends in directions perpendicular to lengthwise directions of handle  18  and slot  26 . 
     Cutting block  34  includes elongate apertures  38 A,  38 B. Apertures  38 A,  38 B are oriented relative to each other to match an intended angle for cuts in an osteotomy procedure. Cutting block  34  may be constructed for a specific procedure, so the angle between apertures  38 A,  38 B may be both patient and case specific. Cutting block  34  may be constructed with 3D printing or additive manufacturing techniques to rapidly produce cutting block  34  to specifications unique to the patient&#39;s anatomy and condition. 
     As shown in  FIG. 2 , apertures  38 A and  38 B extend through cutting block  34  and are defined by opposing interior surfaces  40  of cutting block  34 . Handle  18 , neck  20 , and head  22  of instrument  14  are each roughly planar in shape except for contours where handle  18  and head  22  meet neck  20 . A sleeve  42  extends from head  22  in a direction perpendicular to the planar shape of head  22  and away from handle  18  to define a height of sleeve  42 . Sleeve  42  has a width perpendicular to the height of sleeve  42  and perpendicular to the direction that handle  18  extends from head  22 . The width of sleeve  42  and apertures  38 A,  38 B may be, for example, from 10 mm to 150 mm Apertures  38 A,  38 B may have different widths from one another, but both apertures  38 A,  38 B may be at least as wide as sleeve  42 . In some arrangements, a ratio of the width of sleeve  42  to the width of either aperture  38 A,  38 B may be less than 2:3. Slot  26  extends through head  22  and sleeve  42 , and the sleeve is insertable through apertures  38 A,  38 B. As in the example shown, sleeve  42  may have a length that is shorter than lengths of apertures  38 A,  38 B. Apertures  38 A,  38 B may have differing lengths. However, both apertures  38 A and  38 B may be longer than sleeve  42  as shown. In one example, a ratio of the length of sleeve  42  to the length of either or both of apertures  38 A,  38 B, is less than 2:3. In another example, the ratio of the length of sleeve  42  to the length of either or both of apertures  38 A,  38 B is less than or equal to 1:1. With sleeve  42  disposed through either aperture  38 A,  38 B as illustrated, slot  26  also extends through the respective aperture  38 A,  38 B. A length of slot  26  is aligned with the length of sleeve  42  and is less than the length of sleeve  42 . The length of slot  26  may be, for example, from 10 mm to 100 mm A width of slot  26  is perpendicular to the length of slot  26  and aligned with the width of sleeve  42  and may be, for example, 2 mm, or otherwise less than 3 mm A ratio of the length of slot  26  to the width of slot  26  may therefore be from 5:1 to 50:1. Further, a ratio of the width of slot  26  to the width of sleeve  42  may be less than 2:3. 
     Slot  26  acts to guide sawblade  30  relative to aperture  38 A,  38 B and prevents sawblade  30  from contacting interior surfaces  40 . As in the example shown, apertures  38 A,  38 B may have a close fit to sleeve  42  that restricts possible angular orientations of the sleeve and slot  26  relative to aperture  38 A,  38 B while the sleeve is disposed through the aperture. Due to the close fit of apertures  38 A,  38 B to sleeve  42 , the orientation of apertures  38 A,  38 B control the orientation of cuts made using cutting guide system  10  for a given sleeve in which the relative alignment of sawblade  30  and the sleeve is fixed. Thus, the necessary cutting angles and spacing required between cuts may be specified in the unique specifications according to which cutting block  34  may be manufactured, and the resulting cutting block  34  may guide instrument  14  and sawblade  30  according to the specified angles and spacing. The necessary cutting angles, or the angle of first aperture  38 A relative to the second aperture  38 B may be, for example, anywhere from 0° to 70°. 
     As shown in  FIGS. 3A and 3B , cutting block  34  of cutting guide system  10  includes a patient-specific contour. Cutting block  34  has a proximal side, referring collectively to all surfaces of cutting block  34  that face more proximally than distally, that faces instrument  14  just prior to inserting the instrument into the cutting block. The proximal side of cutting block  34  includes a smooth proximal surface with planar portions on either side of a convex curve. Apertures  38 A,  38 B extend along the curve such that proximal openings of apertures have a non-planar profile. Cutting block  34  also has a distal side, referring collectively to all surfaces of cutting block  34  that face more distally than proximally, from which sawblade  30  extends. The distal side of cutting block  34  includes a concave distal surface that is relatively irregular compared to the proximal surface. The irregularity may be shaped to match features of the patient near bone to be cut. Such features may be specified within the unique specifications according to which cutting block  34  may be manufactured. Further, such features are designed such that a minimum thickness of cutting block  34 , defined as the smallest distance between any point on the distal side of cutting block  34  and a corresponding point on the proximal side of cutting block  34 , exceeds the height of sleeve  42 . The minimum thickness of cutting block  34  may exceed the height of sleeve  42  by, for example, 2 mm. Further still, such features may be designed such that a maximum thickness of cutting block  34 , defined as the greatest distance between any point on the distal side of cutting block  34  and a corresponding point on the proximal side of cutting block  34 , is at most twice the height of sleeve  42 . The height of sleeve  42  may therefore extend along at least 50% of the thickness of cutting block  34 . 
     In use, cutting block  34  of cutting guide system  10  may be fixed to a patient proximate to a bone, e.g., a talus, navicular, cuneiform, or metatarsal bone, or bones to be cut, and then sleeve  42  may be inserted into one of apertures  38 A,  38 B from a proximal side of cutting block  34 . Cutting block  34  may be fixed to the patient by any suitable method for keeping cutting block  34  stable while cutting bone, such as by driving fixation pins through cutting block  34  into bone. Sawblade  30  may be disposed through slot  26  from a proximal side of head  22  before, during, or after inserting sleeve  42  into aperture  38 A or  38 B. After sleeve  42  is inserted into aperture  38 A,  38 B and sawblade  30  is disposed through slot  26 , sawblade  30  may be used to cut bone. In examples where sawblade  30  is part of an oscillating bone saw, cutting bone involves activating the bone saw to cut bone within boundaries set by the interaction of sleeve  42  and aperture  38 A,  38 B or an interior surface  40 . Cutting bone may further involve either one or both of passing sawblade  30  along slot  26  and passing sleeve  42  along aperture  38 , in either case moving sawblade  30  laterally relative to cutting block  34  to perform resection of the bone. In this way, the total travel of sawblade  30  is controlled by both aperture  38  and slot  26 . After cutting within one aperture  38 A,  38 B is complete, sleeve  42  may be removed from the one aperture  38 A,  38 B and inserted into another aperture  38 A,  38 B from the proximal side of cutting block  34 , and the above described process of cutting bone may be repeated along the other of apertures  38 A,  38 B. 
     Referring now to  FIG. 4 , cutting guide system  110  includes instrument  114  and cutting block  134  generally similar in form and function to instrument  14  and cutting block  34  of the arrangement of cutting guide system  10  illustrated in  FIGS. 1-3B , with like elements numbered alike, (e.g., instruments  14  and  114 , cutting blocks  34  and  134 ) except for distinctions set forth below. 
     Cutting block  134  includes a wedge shaped aperture  138  having a trapezoidal profile and two grooves  146 , each groove being adjacent to and parallel to an opposing edge of aperture  138  and extending distally from a proximal surface of cutting block  134 . As shown in  FIG. 5 , grooves  146  extend from the proximal surface of cutting block  134  to a distal surface of the cutting block. A tongue  150  extends distally from head  122  perpendicular to sleeve  126  and is insertable into groove  146 . Grooves  146  are sized to have a close fit to tongue  150  such that instrument  110  is prevented from rotating or translating relative to cutting block  134  except for moving proximally or distally within the plane of sawblade  130  when tongue  150  is disposed in groove  146 . Grooves  146  are spaced from aperture  138  such that sleeve  126  will be held against the adjacent one of interior surfaces  140  defining aperture  138 . Grooves  146  and aperture  138  thereby cooperate to dictate possible cutting paths achievable by use of instrument  110  with cutting block  134 . Locations, sizes, and orientations of grooves  146  and aperture  138  may be specified within parameters unique to a patient&#39;s anatomy and condition according to which cutting block  134  may be constructed. For example, opposing interior surfaces  140  of aperture  138  may be angled with respect to one another by, for example, anywhere from 0° to 70°, and the angle of opposing interior surfaces  140  of cutting block  134  with respect to one another may correspond to an angle of cut paths dictated by cutting block  134  with respect to one another. According to other arrangements, one or both of grooves  146  may have a greater width than a width of tongue  150  such that instrument  110  may slide along the one or both of the grooves laterally relative to cutting block  134 . Because of the trapezoidal profile of aperture  138 , and the alignment of grooves  146  with the non-parallel internal faces  140 , such lateral sliding permits adjustment of spacing of cuts dictated by cutting block  134  without permitting any variance in the relative angle defined by the cuts, as sliding sleeve  142  along one of the non-parallel internal surfaces  140  will change the distance of sleeve  142  from the opposing internal surface  140  while maintaining a constant angle between sleeve  142  and the opposing internal surface  140 . 
     As shown in  FIGS. 6A and 6B , instrument  114  may be applied to the proximal surface of cutting block  134  such that tongue  150  extends distally into groove  146 , sleeve  142  extends distally into aperture  138 , and saw blade  130  extends distally through and out of aperture  138 . Grooves  146  extend along an arcuate portion of cutting block  134  such that their respective openings on the proximal and distal surfaces of cutting block  134  have non-planar profiles. 
     Cutting guide system  110  may be used by securing or fixing patient-specific cutting block  134  to the patient proximal to a bone or bones to be cut by any known method, such as by pins or screws. Instrument  114  may be applied to cutting block  134  such that tongue  150  is disposed within one of grooves  146  and sleeve  142  is disposed within aperture  138  along one of interior surfaces  140 . With instrument  114  so positioned, sawblade  130  may be used through slot  126  to cut bone along the one interior surface  140 . After bone is cut along the one interior surface  140 , instrument  114  may be removed such that tongue  150  is withdrawn from groove  146  and sleeve  142  is withdrawn from aperture  138 . Instrument  114  may then be repositioned for a second cut, which may include reapplying instrument  114  to cutting block  134  such that tongue  150  is disposed in another of grooves  146  and sleeve  142  is disposed within aperture  138  along another of interior surfaces  140 . Sawblade  130  may then be used through slot  126  to cut bone along the other interior surface  140 . 
     Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.