Abstract:
A surgical elevator device that can be used in the reduction of bone fractures, particularly facial bone fractures, and even more particularly zygomatic arch fractures. The elevator device enables accurate measurement of the depth of insertion of the device into tissue space and provides tactile control of fracture location and reduction. In one embodiment, the elevator device comprises a groove on an elevator element for receiving a bone structure. The groove can be formed by a pair of parallel ridges. A projection extending from the elevator provides a pivot point for applying a controlled force to the bone to reduce the fracture. A preferred embodiment further comprises a method of reducing a bone fracture, such as a zygomatic arch fracture.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The application claims priority to U.S. Provisional Application No. 61/310,950 filed on Mar. 5, 2010, the entire contents of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The zygomatic arch is a bone structure located in the cheek area of the face that extends between the zygoma and the temporal bone. Because of the position and prominence of this structure, fractures of the zygomatic arch are a relatively common type of facial injury. 
         [0003]    To treat zygomatic arch fractures, various techniques are used to re-set or “reduce” the fracture, by restoring the injured structure to its normal anatomic position. In some cases, this can be done non-invasively by a “closed reduction,” in which the bone is restored by external manipulation without requiring an incision. Frequently, however, an “open reduction” is needed, which requires a surgical incision for reduction, and optional internal fixation, of the fractured zygomatic arch. 
         [0004]    One common technique for reduction of a zygomatic arch fracture, known as the Gillies&#39; method, involves making a small incision in the skin of the patient&#39;s head, preferably behind the hairline to minimize visible scarring, inserting a surgical elevator device behind the fractured bone, and applying a force against the bone to reduce the arch. Other similar techniques are known that involve inserting a surgical instrument, such as a bone hook, wire, towel clip, or similar device, and applying an outward force against the zygomatic arch to reduce the fracture. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention comprises a surgical elevator device that can be used in the reduction of bone fractures, particularly facial bone fractures, and even more particularly zygomatic arch fractures. The present elevator device enables accurate measurement of the depth of insertion of the device into position adjacent the skeletal feature of interest, provides tactile control of fracture location and reduction, and permits improved control of the magnitude and direction of the force applied to reduce fractures. 
         [0006]    In the existing techniques for reduction of zygomatic arch fractures, using a Rowe zygoma elevator, a bone hook or the like, the successful outcome of the procedure is largely dependent on the skill and technique of the surgeon performing the procedure. With existing techniques, it is often difficult to correctly control the location of the elevator device relative to the fracture, as well as the magnitude and direction of the force applied to reduce the fracture. 
         [0007]    According to one embodiment of the present invention, a surgical elevator device comprises a elevator element that is inserted under the bone, the elevator element having a distal end and a proximal end, an upper surface. A handle for gripping the elevator device is attached to the proximal end of the elevator element. A groove for receiving a bone structure, the groove being located on a first (upper) surface of the distal portion of the elevator element portion; and a base on a second surface of the elevator device. The groove can be formed by a pair of projections, such as parallel ridges on the first elevator surface, and can provide the surgeon with tactile control of the fracture location in relation to the elevator element. The base can extend substantially unidirectionally from the second surface of the elevator, such as the bottom surface of the elevator element, and provides a pivot point for rotation about an axis to enable the transfer of a controlled force from the handle portion to a bone structure within the groove. In one preferred embodiment, the groove is configured and sized to receive a portion of a zygomatic arch, and the controlled force directed away from the patent comprises a lateral outward force to reduce a zygomatic arch fracture. The base can be configured to be placed against an extraoral anatomic feature, such as the temporal bone of the patent to provide a fulcrum. 
         [0008]    In further embodiments, the elevator device includes markings on the elevator element to indicate the depth of insertion of the elevator element into a subject. The portion can include a roughened surface, such as serrations, on the distal end to help prevent the elevator element from slipping against the bone structure. The handle portion is preferably oriented at an angle with respect to the elevator element. 
         [0009]    According to yet another embodiment, a method of reducing a fractured bone using a surgical elevator device comprises making an incision over the temporal bone to enable percutaneous insertion of the elevator element into a subject by manipulating a handle portion of the elevator device; positioning a distal end of the elevator element beneath the fractured bone so that the bone is received by a groove on the first surface; positioning a base extending from a surface of the elevator device against an (extraoral) external surface feature of the subject to provide a pivot point; and rotating the handle towards the subject, using the projection as a pivot, to transfer a substantially lateral outward force to the fractured bone positioned in the groove to reduce the fracture. The user, such as a surgeon, can simultaneously palpate the external surface of the tissue overlying the bone. In a preferred embodiment, the fractured bone comprises a zygomatic arch. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Various aspects of at least one embodiment of the present invention are discussed below with reference to the accompanying figures. In the figures, which are not intended to be drawn to scale, each identical or nearly identical component that is illustrated in the various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. The figures are provided for the purposes of illustration and explanation and are not intended as a definition of the limits of the invention. In the figures: 
           [0011]      FIG. 1  is a side view of an elevator device according to one embodiment of the invention; 
           [0012]      FIG. 2  is a top view of the elevator device of  FIG. 1 ; 
           [0013]      FIG. 3A  is a side view of the tip end of the elevator device; 
           [0014]      FIG. 3B  is a top view of the tip end of the elevator device; 
           [0015]      FIG. 4A  illustrates a projection of an elevator device of the invention; 
           [0016]      FIG. 4B  illustrates an alternative embodiment of the projection; 
           [0017]      FIGS. 5A and 5B  illustrate a surgical procedure using the elevator device of the invention to reduce a zygomatic arch; and 
           [0018]      FIG. 6  illustrates a cross-sectional view of a preferred embodiment of an elevator device used to reduce a zygomatic arch fracture. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Referring now to  FIGS. 1-4B , an elevator device  100  for use in a surgical procedure, for instance, for the reduction of a zygomatic arch fracture, is illustrated. The elevator device  100  generally includes a handle portion  101  and a elevator element  103 . The elevator element portion  103  can be angled with respect to the handle portion  101 , such as shown in the side-view of  FIG. 1 . This angle  106  can be between 20 and 70 degrees, preferably in a range of 30 to 60 degrees. The angle  106  between the handle axis  110  and the elevator axis  102  is thus preferably at least 20 degrees to provide sufficient clearance from the head of the user. The handle portion  101  can include a grip  105  that allows the device  100  to be easily grasped and manipulated by a user. The grip  105  can further include a groove  107  that is positioned to receive the thumb of a user for more precise control of the device  100 . 
         [0020]    The elevator element  103  includes a proximal end  109 , where the element  103  connects to the handle portion  101 , and a distal end  111  terminating at a tip  113 . The portion  103  can have a generally flat upper surface  115 . The upper surface  115  of the portion  103  is generally between about 40 and 60 mm in length, and in one embodiment is about 50 mm in length. Several different lengths can be housed in a kit for use with different feature sizes. As is illustrated in the top view of  FIG. 2 , the width of the portion  103  has a length  108  that is generally between about 10 and 15 mm, and in one embodiment is about 12 mm. The sides of the tip  113  can be rounded over as shown in  FIG. 1 , and form a slightly-curved edge  117  ( FIG. 2 ) where the tip  113  meets the distal end of the flat upper surface  115 . The tip  113  can have a sharp edge to aid with insertion. 
         [0021]      FIGS. 3A and 3B  are side and top views, respectively, of the distal end  111  of the portion  103 , showing several features of the elevator device  100  in greater detail. The upper surface  115  of the portion  103  include a pair of parallel raised ridges  121 ,  123 . The ridges  121 ,  123  define a groove  125  that is preferably sized and shaped to receive an anatomical structure, such as the bone or bone fragments of a fractured zygomatic arch. The ridges  121 ,  123  and the groove  125  can help stabilize the anatomical structure while the elevator  100  is used to apply an outward lateral force against the structure. In one embodiment, the groove  125  further includes a depression  127  in the upper surface  115  of the elevator element. The depression  127  can extend over the entire groove  125  region between the ridges  121 ,  123 , as shown in  FIG. 3A . 
         [0022]    The ridges  121 ,  123  can extend across the entire width of the elevator portion  103 , or, as shown in  FIG. 3B , the ridges  121 ,  123  can extend over a portion of the width of the portion. In the embodiment of  FIGS. 3A and 3B , for example, the ridges  121 ,  123  are each between about 6 and 10 mm in length, with a gap  129  of between about 1 and 2 mm between the end of each ridge  121 ,  123  and the edge of the blade portion  103 . The proximal ridge  121  (i.e., closest to the handle portion  101 ) is preferably located about 5 to 10 mm from the tip  113  of the elevator portion  103 , and the distal ridge  123  (i.e., closest to the blade tip  113 ) is preferably about 1 to 4 mm from the tip  113 . 
         [0023]    The upper surface  115  of the portion  103  preferably includes serrations  131  or a similar surface roughening extending over at least the distal end  111  of the portion  103 . The serrations  131  preferably extend at least over the surface of the groove  125  between the ridges  121 ,  123 , and preferably also extend from the distal ridge  123  to the tip  113  of the portion  103 . The groove  125  can have a length  112  generally in a range of 2-8 mm. The serrations  131  increase the surface area of the elevator element and increase the frictional forces between the elevator and any tissue or anatomical structures contacting the elevator, and thus helps prevent the elevator from slipping relative to an anatomical structure, such as a zygomatic arch, during a surgical procedure, such as a fracture reduction. As shown in  FIG. 3B , the serrations  131  can be in two sections, with a first serrated surface in the groove  125 , and a second surface having finer serrations proximate the tip  113 . 
         [0024]    The elevator device  100  can further include markings  133 , such as metric units (millimeters) on the portion  103  of the device, as shown in  FIG. 1 , that can aid the user in determining the depth of insertion when the elevator device  100  is inserted into a patient. 
         [0025]    Turning now to  FIGS. 1 and 4A , according to one embodiment, the elevator device  100  includes a projection  135  that extends from the bottom side at a proximal end of the elevator portion  103 . In a preferred embodiment, the projection can extend “unidirectionally,” meaning that where the upper surface  115  of the blade portion  103  defines a plane, the projection  135  extends in one direction relative to the plane. Conversely, the handle portion  101  can extend unidirectionally in an opposite direction relative to the plane. The projection  135  is preferably located at or near the proximal end  109  of the portion  103 . The projection  135  can be a ridge structure with a substantially rectilinear cross-section, such as shown in  FIGS. 1 and 4A . In other embodiments, such as shown in  FIG. 4B , the projection  135  can comprise a generally curved surface  138  extending from the bottom of the portion  103 . Other shapes can be used for the projection  135 . 
         [0026]    The projection  135  can extend down from the portion  103  a distance, d, of between about 8 and 15 mm, and preferably about 12-14 mm. The projection  135  can have a width of between about 6 and 15 mm, and preferably extends across most or all of the width of the portion  103 , as shown in phantom in  FIG. 2 . In the embodiment of  FIG. 4A , the generally flat bottom surface of the projection  135  with area  137 , has a length, L bot , that is between about 5 and 15 mm, and is preferably about 8 mm. The projection  135  can be tapered to be wider at its top, where the projection  135  meets the portion  103 , and narrower at its bottom surface. In the embodiment of  FIGS. 1 and 4A , for example, the projection  135  can have a length, L top , of about 5 and 20 mm long at its top, and is preferably about 11 mm. 
         [0027]    According to one aspect, the projection  135  comprises a unidirectional member that provides a fulcrum, such that by rotating the handle portion  101  in a first direction, with the end  114  of the projection  135  serving as a fixed pivot point, the distal end  111  of the elevator element  103  is caused to move in an arcuate motion in a second, opposing direction. An advantage of this design is that during an invasive medical procedure, such as reduction of a zygomatic arch fracture, the user is able to more precisely control the magnitude and direction of the outward lateral force applied to the patient by the elevator device  100 . 
         [0028]      FIGS. 5A and 5B  illustrate the elevator device  100  of the present invention being used for a medical procedure, specifically, a reduction of a zygomatic arch fracture. As shown in  FIG. 5A , a small incision  141  (e.g., 2 cm) is made in the skin of a patient  140  in the vicinity of the fractured zygomatic arch  143 , as is known in standard medical techniques for reduction of a zygomatic arch fracture (e.g., the Gillies&#39; method, etc.). The incision is preferably made percutaneously on an external surface on the side of the patient&#39;s head, for example, in the temporal fossa or orbital regions. In one embodiment, a temporal incision is made through the superficial fascia and subcutaneous tissue and into the deep temporal fascia that overlays the temporalis muscle. The superficial fascia and subcutaneous tissue can be retracted. An incision can be made through the deep temporal fascia to expose the temporalis muscle and the temporal bone. 
         [0029]    Next, as shown in  FIG. 5B , the elevator device  100  of the present invention is inserted through the incision  141 , with the surgeon manipulating the device  100  until the distal end  111  of the portion  103  is positioned between the fractured bone and the underlying anatomy. In one embodiment, the elevator device  100  passes between the deep temporal fascia and the underlying temporalis muscle and temporal bone. The distal end  111  of the elevator passes between the zygomatic arch and the coronoid process. The surgeon can use manual palpitation of the arch structure  143  to determine its position relative to the incision  141  point, and the graduated markings  133  on the elevator device  100  can determine the depth of insertion of the elevator device and consequently aid the surgeon in properly positioning the distal end  111  of the portion  103  under the fractured bone. As shown in  FIG. 6 , the elevator device  100  is positioned such that the fractured arch  143  lies between the parallel ridges  121 ,  123  of the elevator, and is received within the groove  125  formed between the ridges  121 ,  123 . The ridges  121 ,  123  can further provide the surgeon with a tactile feedback of the position of the elevator with respect to the fractured bone. The serrations  131  ( FIG. 3B ) can help prevent the blade and bone from sliding relative to one another. 
         [0030]    To reduce the fracture, the surgeon places the projection  135  against an anatomic feature of the patient, and rotates the handle portion  101  downwards (i.e., towards the patient). In a preferred embodiment, the projection  135  is placed against an extraoral anatomic feature of the patient, such as a bone or muscle. In one embodiment, the projection  135  is placed against the temporal bone at  160  where the incision  141  has exposed a portion thereof. The projection  135  acts as a fixed pivot point, and transfers the force of the rotation of the handle portion  101  towards the patient (see arrow  151 ) into a substantially lateral outward force (see arrow  153 ) at the distal end  111  of the portion  103 . The substantially lateral outward force  153  of the portion  103  acts on the arch structure  143  to reduce the fracture. The surgeon can manually exert a counterforce  162  to the same region to control the application of force. The size of the surface area on the bottom of projection  135  can be enlarged to distribute the force. A separate plate  170  can be placed over the incision with a recess  172  to receive the base projection  135  which distributes the force to a larger area. After the fracture is reduced, the elevator device  100  is withdrawn through the incision  141 , and the incision  141  can be closed. 
         [0031]    Although the present elevator device is described herein in connection with the reduction of a zygomatic arch fracture, it will be understood that the present elevator device can be used for other surgical procedures on human and non-human (mammalian) subjects. 
         [0032]    The elevator device  100  of the present invention can be made of one or more surgical-grade materials, including a metal such as stainless steel, for example which can be readily sterilized for further use. Alternatively, the device can be made of a rigid plastic material and disposed of after a single use. In a preferred embodiment, the elevator device  100  can be a single, unitary piece, Alternatively, the elevator device  100  can be assembled from a plurality of separate components to provide a composite structure, such as a plastic handle, to facilitate gripping thereof by the hand of the surgeon which can be detached for use with different size elevator elements. 
         [0033]    While the invention has been described in connection with specific methods and apparatus, those skilled in the art will recognize other equivalents to the specific embodiments herein. It is to be understood that the description is by way of example and not as a limitation to the scope of the invention and these equivalents are intended to be encompassed by the claims set forth below.