Abstract:
A medical instrument set and method of use for surgically treating bony aberrations of the calcaneus such as calcaneal compression fractures. The present medical instrument set allows surgical treatment of bony aberrations through a minimally invasive procedure that provides better outcomes than both a closed reduction and an open reduction procedure. The medical instrument set includes one or more of an access needle, drill, depth guide, cement plunger, and curette. The access needle is used to provide access to a desired calcaneal site and is characterized by a cannula and a removable trocar tip. The drill is used to bore into the calcaneus. The depth guide is used to visually indicate how far a medical instrument extends beyond and/or through the access needle cannula. The cement plunger is used to introduce bone cement into the desired calcaneal site. The curette is used to mechanically create a void at the desired calcaneal site.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This U.S. non-provisional patent application claims the benefit of and/or priority under 35 U.S.C. §119(e) to U.S. provisional patent application Ser. No. 62/213,364 filed Sep. 2, 2015 titled “Medical Instrument Set and Method of Use for Treating Bony Aberrations of the Calcaneus,” the entire contents of which is specifically incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to medical instruments and methods of use and, particularly, to medical instruments and methods of use for treating bony aberrations of the calcaneus such as calcaneal compression fractures. 
       BACKGROUND 
       [0003]    The foot has many bones of various sizes, shapes and function. A main bone of the foot is the heel bone or calcaneus. The calcaneus is a large tarsal bone that articulates anteriorly with the cuboid bone and superiorly with the talus bone. The calcaneus transmits the majority of body&#39;s weight from the talus bone to the ground. Because of this, the calcaneus may experience bony aberrations such as fractures and/or other types of conditions due to various reasons. 
         [0004]    Calcaneal fractures are often attributed to shearing stress adjoined with compressive forces combined with a rotary direction. These forces are typically linked to injuries in which an individual falls from a height, is involved in an automobile accident, or undergoes muscular stress where the resulting forces can lead to fracture. Calcaneal fractures can also be the result of problems associated with osteoporosis and/or diabetes. 
         [0005]    No matter the cause, calcaneal fractures causes pain over the heel area. Other symptoms include the inability to bear weight over the involved foot, limited mobility of the foot, and limping. The area typically includes swelling, redness, and hematomas. The heel may also become widened with associated edema due to displacement of lateral calcaneal border. 
         [0006]    Treatment may be non-surgical or surgical depending on the particular case. A closed reduction with or without fixation, or fixation without reduction are two non-surgical treatments. If surgical treatment is indicated, a conservative treatment is a closed reduction with percutaneous fixation. This approach however, has its pros and cons. Pros include less wound complications, better soft tissue healing, and decreased intraoperative time. Cons include an increased risk of inadequate calcaneal bone fixation compared to open reduction treatments. This can cause future consequences for the patient. Therefore, open reduction with internal fixation (ORIF) is generally the preferred surgical treatment, particularly for displaced intrarticular fractures. Nonetheless, as with any open surgical procedure, there are associated risks. 
         [0007]    In view of the above, it is apparent that improvements can be made in the surgical treatment of bony aberrations, particularly in medical instruments and their method of use for treating bony aberrations of the calcaneus such as calcaneal compression fractures. As such, it is desirable to have a better surgical treatment for bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures that overcomes the deficiencies of the prior art. It is therefore desirable to have medical instruments and methods of their use for surgically treating bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention achieves the above-stated desires by providing a medical instrument set and method of use for surgically treating bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures. The present medical instrument set allows surgical treatment of bony aberrations through a minimally invasive procedure. The minimally invasive procedure provides better outcomes than both a closed reduction and an open reduction. 
         [0009]    The medical instrument set includes one or more of an access needle, a drill, a depth guide, a cement plunger, and a curette. 
         [0010]    The access needle, or trocar, is used to provide access to a desired calcaneal site and is characterized by a cannula and a removable trocar tip. The cannula provides a hollow (cannulated) shaft that is open at both a distal end and a proximal end thereof and is sized to receive the trocar tip and allow a sharpened end of the trocar tip to extend beyond the distal end of the cannula. A handle is situated about the proximal end of the hollow shaft and provides access to the hollow shaft via the open proximal end of the hollow shaft. The handle is preferably, but not necessarily, ergonomically configured for easy manipulation by the user. 
         [0011]    The trocar tip includes a seal for the hollow of the shaft of the cannula in the form of a cap that is situated on a proximal end of an elongated rod whose distal end comprises the sharpened blade. The elongated rod of the trocar tip has an outer diameter that is slightly less than inner diameter of the shaft hollow of the cannula and a length to at least extend to the open distal end of the hollow shaft of the cannula. 
         [0012]    Structure of the cap cooperates with a cap reception structure of the handle to removably retain the cap on the handle. This retains the elongated rod within the hollow shaft of the cannula, the sharpened end extending beyond the hollow shaft of the cannula, and the hollow shaft of the cannula sealed at its proximal end. The removable trocar tip provides controlled access to the open proximal end and thus the hollow of the shaft such that an item or items may be inserted into and through the hollow shaft of the cannula when the trocar tip is removed. In an exemplary form, the cap reception structure includes a slot that accepts a flange structure of the cap. 
         [0013]    The drill is used to bore into the calcaneus and is characterized by a preferably, but not necessarily, solid shaft having bone drill threading on a distal end of the shaft, and a handle on a proximal end of the shaft. The shaft has a working length sufficient to allow the distal bone drill threading of the shaft to extend beyond the distal end of the cannula of the access needle. The bone drill threading or drill length at the distal end of the drill shaft is adequate to penetrate a desired depth into the calcaneus. 
         [0014]    The depth guide is used to visually indicate how far a medical instrument, portion or shaft thereof, extends through the access needle cannula and/or beyond the distal end of the access needle cannula and is characterized by a generally cylindrical body with a head at one end and an elongated portion extending from the head, the elongated portion having a smaller diameter than the head. A bore extends through the body from the head through the elongated portion. 
         [0015]    A fitting is connected to a marker that is disposed in the elongated portion with the elongated portion having demarcations that show depth of an instrument that extends through the depth guide. The fitting is on the head opposite the elongated portion and is configured to receive the shaft of a medical instrument. As the fitting moves up and down, the marker correspondingly moves up and down. The fitting has a bore to receive the shaft of a medical instrument and to allow the shaft of the medical instrument to extend through the depth guide. 
         [0016]    The cement plunger is used to introduce bone cement such as bone void filler (BVF) into the desired calcaneal site and is characterized by a cannulated shaft having an open distal end and an open proximal end with a handle disposed at the proximal end. The handle incorporates a Luer Lock or the like at the open proximal end that removably receives a cap and a syringe, the syringe having bone cement (e.g. BVF) for injection through the cannulated shaft of the cement plunger and into a void and/or fracture at the desired calcaneal site. 
         [0017]    The curette is used to mechanically create a void at the desired calcaneal site and is characterized by a solid shaft having a distal end with a blade, and a proximal end with a handle. The shaft has a working length sufficient to allow the distal blade of the shaft to extend beyond the distal end of the access needle cannula. The blade is preferably, but not necessarily, curved or bent relative to the shaft and includes a configured tip for creating a void in the calcaneus. The blade has a length sufficient to reach the desired calcaneal site and create the desired calcaneal void. 
         [0018]    Treatment of bony aberrations of the calcaneus using the present medical instrument set provides a minimally invasive approach. A plugged (via the trocar tip) access needle is placed into the calcaneus via a stab incision or a simple puncturing the plugged access needle through the skin and into the bone. With the use of fluoroscopy or a die marker, a physician can locate the bone fracture, void or edema with the tip of the inserted plugged access needle. This may be accomplished by hand insertion or with the use of a mallet. In one manner, once the location is identified, the trocar tip of the access needle is removed and a k-wire is inserted into the lumen (access needle shaft or cannula) to preserve the location. After k-wire insertion, the cannula/shaft of the access needle is removed and then a larger cannula is inserted over the k-wire. Through the larger cannula, a mechanical bone creator (curette) is fed into the desired calcaneal site. In another manner, the curette is designed to fit within the cannula of the access needle. Through mechanical (e.g. hand) manipulation, the blade of the curette creates a small fenestra or void at the distal end of the cannula for reception of bone cement (e.g. BVF) in order to augment and stabilize the fracture. The curette is removed after the void has been created in order to fill the distal void with the BVF. A syringe of BVF attaches to the proximal end of the cannula preferably, but not necessarily, via a Luer Lock or the like. The BVF is injected into the calcaneal site to stabilize the fracture. 
         [0019]    It should be noted that the same cannula mechanism may be used to inject BVF into the central lumen of a fracture screw in the same location. In some instances, the surgeon will install a screw across the fracture line of a calcaneal break. The cannula is configured to be inserted into the screw to allow for BVF to be injected into the fracture site via the cannula and fracture screw. 
         [0020]    Further aspects of the present invention will become apparent from consideration of the drawings and the following description of a form of the invention. A person skilled in the art will realize that other forms of the invention are possible and that the details of the invention can be modified in a number of respects without departing from the inventive concept. The following drawings and description are to be regarded as illustrative in nature and not restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The features of the invention will be better understood by reference to the accompanying drawings which illustrate a form of the present invention, wherein: 
           [0022]      FIG. 1  is a plan view of a curette of the present medical instrument set for treating bony aberrations of the calcaneus; 
           [0023]      FIG. 2  is a side view of the curette of  FIG. 1 ; 
           [0024]      FIG. 3  is a side view of a depth guide of the present medical instrument set for treating bony aberrations of the calcaneus; 
           [0025]      FIG. 4  is another side view of the depth guide of  FIG. 3 ; 
           [0026]      FIG. 5  is a plan view of a drill of the present medical instrument set for treating bony aberrations of the calcaneus; 
           [0027]      FIG. 6  is a side view of the drill of  FIG. 5 ; 
           [0028]      FIG. 7  is a plan view of an access needle of the present medical instrument set for treating bony aberrations of the calcaneus; 
           [0029]      FIG. 8  is a side view of the access needle of  FIG. 7 ; 
           [0030]      FIG. 8A  is a side view of a cannula portion of the access needle of  FIGS. 7 and 8 ; 
           [0031]      FIG. 8B  is a side view of a trocar tip portion of the access needle of  FIGS. 7 and 8 ; 
           [0032]      FIG. 9  is a plan view of a cement plunger of the present medical instrument set for treating bony aberrations of the calcaneus; 
           [0033]      FIG. 10  is a side view of the cement plunger of  FIG. 9 ; 
           [0034]      FIG. 11  is a first view of several views of one or more of the various medical instruments of the present medical instrument set for treating bony aberrations of the calcaneus illustrating a procedure for treating calcaneal compression fractures, the first view showing a positioned cannula of the access needle (i.e. the trocar tip having been removed from the cannula of the access needle); 
           [0035]      FIG. 12  is a second view of the several views of one or more of the various medical instruments of the present medical instrument set for treating bony aberrations of the calcaneus illustrating the procedure for treating calcaneal compression fractures, the second view depicting the cannula of the access needle of  FIG. 11  with the drill inserted through the hollow shaft of the cannula of the access needle; 
           [0036]      FIG. 13  is a third view of the several views of one or more of the various medical instruments of the present medical instrument set for treating bony aberrations of the calcaneus illustrating the procedure for treating calcaneal compression fractures, the third view depicting the depth guide received onto the handle of the cannula of the access needle, with the curette received in the depth guide and in the shaft of the cannula of the access needle; 
           [0037]      FIG. 14  is a fourth view of the several views of one or more of the various medical instruments of the present medical instrument set for treating bony aberrations of the calcaneus illustrating the procedure for treating calcaneal compression fractures, the fourth view depicting the cement plunger received in the shaft of the cannula of the access needle; 
           [0038]      FIG. 15  is a partial view of a distal end of a notched cannula that may be part of one or more the present medical instruments, such as the access needle, or as a separate medical instrument of the present medical instrument set; 
           [0039]      FIG. 16  is a view of a cannulated and fenestrated bone screw of the present medical instrument set with the notched cannula received in the cannula of the bone screw; and 
           [0040]      FIG. 17  is an enlarged view of the distal end of the bone screw of  FIG. 16 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0041]    Referring to  FIGS. 1 and 2 , there is depicted an exemplary form of a curette generally designated  10 , fashioned in accordance with the present principles and being one medical instrument of a set of medical instruments for treating bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures. The curette has a handle  12  with a shaft  14  extending from the handle  12  such that the handle  12  is situated at a proximal end of the shaft  14 . A blade  16  is situated at a distal end of the shaft  14 . As best seen in  FIG. 2 , the blade  16  is defined by curved portion  17  that extends from the distal end of the shaft  14  with a scoop  18  at the end of an angled portion  17 . The shaft  14  has a working length (e.g. 23.8 cm) sufficient to allow the blade  16  to extend beyond the distal end of the access needle shaft when the curette is inserted into an access needle (see access needle  40  of  FIGS. 7-8 ). The blade has a blade length (e.g. 20 mm) adequate to reach and create a void at the desired calcaneal site. 
         [0042]    Referring to  FIGS. 3 and 4 , there is depicted an exemplary form of a depth guide, generally designated  20 , fashioned in accordance with the present principles and being one medical instrument of a set of medical instruments for treating bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures. The depth guide  20  has a generally cylindrical body  21  with a head  23  at one end and an elongated portion  22  extending from the head  23 , the elongated portion  22  having a smaller diameter than the head  23 . A bore (not seen) extends through the body  21  from the head  23  through the elongated portion  22 . A fitting  24  is connected to a marker  26  that is disposed within a chamber  29  of the elongated portion  22 . The fitting  24  has a bore (not shown) that receives an instrument shaft. A number of demarcations  28  are provided along the chamber  29  of the elongated portion  22  that show depth. As the fitting  24  moves with the instrument, the marker  26  and thus mark  27  moves along the chamber  29 . A mark  27  shows depth relative to the demarcations  28 . A button  25  is provided which upon compression allows for fitting  24  to translate. As fitting  24  elongates the curette tip exposure reduces when stacked upon the access cannula. The amount of tip exposure runs from 4 mm to 32 mm. 
         [0043]    Referring to  FIGS. 5 and 6 , there is depicted an exemplary form of a drill, generally designated  30 , fashioned in accordance with the present principles and being one medical instrument of a set of medical instruments for treating bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures. The drill  30  has a handle  32  with a shaft  34  extending from the handle  32  such that the handle  32  is situated at a proximal end of the shaft  34 . Threads or threading  36  is situated at a distal end of the shaft  34 . The shaft  34  has a working length (e.g. 21.9 cm) sufficient to allow the threading  36  to extend beyond the distal end of the access needle shaft when the drill is inserted into the access needle  40  (see  FIGS. 7-8 ). The length of threading  36  defines a drill length. The drill length (e.g. 38 mm) is adequate to reach a desired calcaneal site. 
         [0044]    Referring to  FIGS. 7, 8, 8A, and 8B , there is depicted an exemplary form of an access needle, generally designated  40 , fashioned in accordance with the present principles and being one medical instrument of a set of medical instruments for treating bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures. The access needle  40  is characterized by a cannula portion (cannula)  41  (see  FIG. 8A ) and a trocar tip portion (trocar tip)  43  (see  FIG. 8B ). The cannula portion  41  includes a handle  42  having a central body  45  with a hollow shaft  44  extending from the body  45  such that the handle  42  is situated about an open proximal end of the hollow shaft  44 . A boss  65 , situated on an end of the body  45 , is in communication with the open proximal end of the hollow shaft  44 , and is configured to releasably receive a cap  48  of the trocar tip  40  (see  FIG. 8B  and below). The distal end of the hollow shaft  44  terminates in an open end  46 . The hollow shaft  44  is thus open from its distal end  46  to its proximal end  65 . The shaft  44  has a working length (e.g. 12.9 cm) sufficient to allow the other medical instruments to extend beyond the end  46  when inserted into the hollow shaft  44 . The handle  42  is preferably, but not necessarily, ergonomically configured for easy manipulation by the user. 
         [0045]    The trocar tip  43  includes a seal for the open proximal end of the hollow shaft  44  of the cannula  41  in the form of a cap  48  that is configured to releasably join with the boss  65  of the handle  42  such that the proximal opening of the hollow shaft  44  of the cannula  41  is obturated. An elongated rod  66  extends from the cap  48  and terminates at its distal end in a pointed blade  67 . The pointed blade  67  is preferably, but not necessarily, cut at an angle or bias. Other sharp and/or pointed style tips may be used. The rod  66  is sized such that it is slightly less than the inner diameter of the shaft hollow  44  with a length to at least extend to the open distal end  46  of the hollow shaft  44  such that the blade  67  is beyond the open distal end  46 . 
         [0046]    When the cap  48  is releasably held over and/or onto the boss  65  of the handle  42 , the rod  66  extends through the hollow shaft  44  and the blade  67  is exposed, thereby releasably retaining the trocar tip  43  in the cannula  41 . Structure in the form of a flange  68  of the cap  48  cooperates with a cap reception structure  47  of the handle  42  to removably retain the cap  48  on the handle  42 , and thus the rod  66  within the hollow shaft  44 . The removable trocar  43  provides controlled access to the hollow shaft  44  such that an item or items may be inserted into and through the hollow shaft  44  when the trocar  43  is removed. In an exemplary form, the cap reception structure  47  of the handle  42  includes a slot  49  that accepts the flange structure  68  of the cap  48 . 
         [0047]    Referring to  FIGS. 9 and 10 , there is depicted an exemplary form of a cement plunger, generally designated  50 , fashioned in accordance with the present principles and being one medical instrument of a set of medical instruments for treating bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures. The cement plunger  50  has a handle  52  with a hollow shaft  54  extending from the handle  52  such that the handle  52  is situated at a proximal end of the shaft  54 . The distal end of the shaft  54  terminates in blunt tip  55 . The hollow shaft  54  thus has an opening at its distal end and an opening at its proximal end. The shaft  54  has a working length (e.g. 21.9 cm) sufficient to extend through and beyond the distal tip  46  of the hollow shaft  44  of the cannula  41  of the access needle  40 . The handle  52  includes a closure structure  53  formed as a cap  56  that removably couples with mating structure (not seen) on an end  57  of the handle  52 , the end  57  providing access to the hollow shaft  54  from its proximal end. The mating structure may be a Luer Lock or the like. Once the cap  56  is removed, a syringe (not shown) having a mating Luer Lock (structure) is received on the end  57 , the syringe having BVF or other bone cement. 
         [0048]      FIGS. 11-14  depict several of the present medical instruments as used in the present method for treating bony aberrations of the calcaneus and, for this particular illustration, a method of treating a calcaneal compression fracture that provides a minimally invasive approach.  FIG. 11  shows the cannula  41  of the access needle  40  with the trocar tip  43  of the access needle  40  has been removed after the access needle  40  was placed into the calcaneus (not shown) via a stab incision or a simple puncturing the plugged access needle  40  through the skin and into the bone. With the use of fluoroscopy, die marker or otherwise, a surgeon locates the bone fracture with the blade  67  of the trocar tip  43  of the access needle  40 . This may be accomplished by hand insertion, with the use of a mallet, or otherwise. In  FIG. 12 , the drill  30  is shown inserted into the cannula  41  with its bone drill threading  36  extending beyond the tip  46  of the cannula shaft  44 . The drill  30  may then be used to reach a desired location within the calcaneus through hand manipulation (i.e. twisting) of the handle  32  of the drill  30 . 
         [0049]    In  FIG. 13 , the drill guide  20  is shown coupled to the cannula  41  of the access needle  40  (particularly, the handle  42  thereof) with the curette  10  situated in the drill guide  20  and cannula  41 . The curette  10  is situated in the drill guide  20  such that the handle  12  of the curette  10  abuts the fitting  24 . The curette  10  is shown at a maximum depth relative to the cannula  41  such that the blade  16  extends a maximum distance beyond the tip  46  of the cannula  41 . The mark  27  of the marker  26  of the depth guide will be at its lowest point within the indicator  29  thus indicating a maximum depth. Upward and downward movement of the fitting  24  of the depth guide  20  moves the position of the curette up and down relative to the cannula  41  thus setting a depth of the blade  16  of the curette  10  (or other of the present medical instruments), while correspondingly moving the mark  26  of the drill guide  20 . Through mechanical (e.g. hand) manipulation, the blade  16  of the curette  10  creates a small fenestra or void at the distal end (tip  46 ) of the cannula  41  for reception of bone cement (e.g. BVF) in order to augment and stabilize the fracture. The curette  10  and the depth guide  20  are removed after the void has been created in order to fill the distal void (not shown) with the BVF. In  FIG. 14 , the cement plunger  50  is shown inserted into the cannula  41  in order to provide BVF to the distal void (not shown) of the calcaneus (not shown). The cap  56  is removed and a syringe of BVF attaches to handle  52  of the cement plunger  50  for injecting the BVF into the calcaneal site. 
         [0050]      FIG. 15  depicts a cannula  60  as a medical instrument of the present set of medical instruments or as an augmentation of one of the present medical instruments such as the cannula  41  of the access needle  40 . The cannula  60  is defined by longitudinal shaft  62  having an internal, longitudinal bore  63  extending from a proximal end (not shown) thereof to the distal end  61  thereof. A fenestra or opening  64 , which may be one of several, is disposed in the side of the shaft  62  proximate the distal end  61  thereof. This cannula can be used to inject BVF into the central lumen of a bone fracture screw (such as bone fracture screw  70  shown in  FIGS. 16 and 17 , and described in greater detail below) in the same desired calcaneal site. In some instances, the surgeon will install a bone fracture screw across the fracture line of a calcaneal break. The cannula is thus designed to be inserted into the bone fracture screw  70  (see  FIG. 16 ) to allow for BVF to be injected into the fracture site, via the cannula  60  and bone fracture screw  70 . 
         [0051]    Referring to  FIGS. 16 and 17 , there is depicted an exemplary form of a bone fracture screw, generally designated  70 , fashioned in accordance with the present principles and being one medical instrument of a set of medical instruments for treating bony aberrations of the calcaneus such as, but not limited to, calcaneal compression fractures. The bone fracture screw  70  has a shaft  72  having a head  73  at a proximal end of the shaft  72 , and bone screw threading  74  at a distal end of the shaft  72 . A longitudinal bore  75  extends through the shaft  72  from the proximal end to the distal end. The bone fracture screw  70  includes several fenestrae  76  situated about the bone screw threading  74  at the distal end of the shaft  72 . The fenestrae  64  of the cannula  60  may be aligned with the fenestrae  76  of the fracture screw  70 . 
         [0052]    It should be appreciated that many medical instrument sets may be formed using permutations of the various medical instruments described herein. 
         [0053]    It should also be appreciated that dimensions of the medical instruments of the present medical instrument set&#39;s components, structures, and/or features can be altered as desired.