Method and Apparatus for Fixation of Bone During Surgical Procedures

1. Field of the Invention

This invention relates to prosthetic implant devices which are used in surgical procedures, and more particularly to a method and apparatus for fixation of bone during surgical procedures.

2. Description of the Related Art

During various types of surgical procedures, it is often necessary to remove and reattach a portion of bone such as a human skull. In certain neurosurgical procedures, for example, a cranial bone flap is first formed on the skull and then removed so that a surgeon can access the portions of the brain that are of concern. Such a cranial bone flap may typically be formed by drilling several burr holes through the cranial vault. After the burr holes have been drilled, osteotomies are made by a saw in the skull which connect the burr holes. The saw may typically have a guide nose which serves to avoid injuries to the dura mater. The bone flap is then removed so as to provide access to the brain. Once the procedures which are performed on the brain have been completed, the bone flap is reattached to the skull.

In craniofacial procedures, a bone segment is first formed on the skull in a manner similar to that described above and then the bone segment is removed from the skull. The bone segment is then shaped by the surgeon so as to provide the desired cosmetic appearance. Once the bone segment has been shaped in the desired manner, the bone segment is then reattached to the skull.

A variety of devices are commercially available which are used for securing a bone flap or a bone segment to the skull. For example, U.S. Pat. No. 5,210,737 discloses a device having a plurality of slots which extend radially from the center of the device. The slots are indicated as being used for forming a plurality of vanes in the device. This device, however, does not provide a high degree of flexibility with respect to placement of the bone screws which are used to secure the device to both the skull and the bone flap. Rather, the placement of the bone screws with respect to the body of the device is fixed and is determined by the specific geometry of the device. In addition, the slots which are located between the vanes of this device tend to limit the rigidity of the device. Finally, altering one or more of the vanes tends to deform the shape of the device which may cause interference at the interface between the device and both the skull and the bone flap.

In one embodiment, the present invention relates to an apparatus for fixation of bone during surgical procedures. The apparatus includes a body member which is operable to cover at least a portion of the bone. The apparatus also includes at least one attachment member which is operable to be secured to the bone. The attachment member includes means for receiving a bone screw and is operable to be secured to the bone upon receipt of the bone screw. The apparatus further includes an extension member that mechanically communicates with the body member and the attachment member and is operable to be displaced with respect to the body member. Because the extension member is displaceable with respect to the body member, the attachment member may be secured to the bone by the bone screw at a plurality of different positions with respect to the body member by varying the displacement of the extension member with respect to the body member.

In another embodiment, the present invention also relates to a method for covering a portion of a bone. The method includes the initial step of forming a body member which is operable to cover a portion of the bone, at least one attachment member which is operable to be secured to the bone, as well as an extension member mechanically communicating with the body member and the attachment member. The method also includes the step of determining the desired position of the body member as well as the bone screw with respect to the bone. The method also includes displacing the extension member with respect to the body member and then securing the apparatus to the bone by causing the bone screw to engage the attachment member and the bone.

Accordingly, an advantage of the present invention is to provide a method and apparatus for fixation of bone during surgical procedures which is relatively simple to use and which is adaptable to a variety of patients as well as a variety of surgical procedures and situations.

A further advantage of the present invention is to provide a method and apparatus for fixation of bone during surgical procedures in which the location of bone screws which attach the apparatus to bone may be varied.

Another advantage of the present invention is to provide a method and apparatus for fixation of bone during surgical procedures which is relatively strong yet is able to provide a relatively high degree of flexibility to the surgeon during fixation of the bone.

Another advantage of the present invention is to provide a method and apparatus for fixation of bone during surgical procedures in which the flow of fluid through the apparatus is relatively unimpeded yet is able to provide a relatively high degree of strength.

A further advantage of the present invention is to provide a method and apparatus for fixation of bone during surgical procedures which is expandable to accommodate the growth of the patient.

Another object of the present invention is to provide a method and apparatus for fixation of bone during surgical procedures which is relatively simple and which is easy to fabricate.

Various advantages of the present invention will become apparent to one skilled in the art upon reading the following specification and reference to the following drawings in which:

FIG. 1 is a view of the apparatus for fixation of bone during surgical procedures shown in operative association with a cranial bone flap and a human skull;

FIG. 2 is an enlarged front elevational view of the apparatus for fixation of bone during surgical procedures shown in FIG. 1 according to the first preferred embodiment of the present invention;

FIG. 3 is an enlarged front elevational view of the apparatus for fixation of bone during surgical procedures according to the first preferred embodiment of the present invention shown in FIG. 2 with one of the extension members being displaced;

FIG. 4 is an enlarged front elevational view of the apparatus for fixation of bone during surgical procedures shown in FIG. 1 according to the second preferred embodiment of the present invention;

FIG. 5 is an enlarged front elevational view of the apparatus for fixation of bone during surgical procedures shown in FIG. 1 according to the third preferred embodiment of the present invention; and

FIG. 6 is an enlarged front elevational view of the apparatus for fixation of bone during surgical procedures shown in FIG. 1 according to the fourth preferred embodiment of the present invention.

The following discussion of the preferred embodiments of the present invention is merely exemplary in nature. Accordingly, the discussion is in no way intended to limit the scope of the invention, the application of the invention, or the use of the invention.

Referring to FIG. 1, an apparatus 10 for fixation of bone during surgical procedures is shown. The apparatus may be used for reattaching a cranial bone flap 12 to a skull 14 after the cranial bone flap 12 has been removed and various surgical procedures have been performed. In particular, the apparatus 10 may be used to cover a burr hole (not shown) which is formed during the creation of the cranial bone flap 12. As will be appreciated by those skilled in the art, the apparatus 10 may be used in a variety of neurosurgical and/or craniofacial procedures. In addition, the apparatus 10 may be used with other types of procedures where it is desirable to fixate bone, bone segments or other suitable forms of biological material.

The apparatus 10 according to the first preferred embodiment will now be described in further detail with reference to FIGS. 2 and 3. The apparatus 10 includes a body member 18 which is operable to cover at least a portion of a bone which may be the cranial bone flap 12, the skull 14, a burr hole, or any other suitable biological material. The body member 18 is substantially circular in configuration in that it is at least partially defined by a center and a radial centerline rotated about the center. The body member 18 may be convexly curved to generally correspond to the shape of the skull 14. In this case, it is preferable that the shape of the body member be formed by an arc with a radius of approximately 3 inches. While the body member 18 is preferably made from commercially pure titanium, it will be understood that any other suitable material may be used which is body compatible. Such materials include titanium alloys, chromium-cobalt-molybdenum alloys or other suitable materials.

To provide a plurality of flow passages through the body member 18 for fluid flowing proximate to the bone, the body member 18 further includes a first plurality of elongated apertures 20 and a second plurality of elongated apertures 22. The first plurality of elongated apertures 20 are arranged generally concentric with respect to the body member 18 in a region adjacent to the center of the body member 18. The second plurality of elongated apertures 22 are also arranged generally concentric with respect to the body member 18 though at a further distance from the center of the body member 18 than the first plurality of elongated apertures 20. Disposed centrally within the body member 18 is a central aperture 24 which also provides a path for fluids to flow through the apparatus 10 as well as provides an additional location for receiving a bone screw.

To provide means for securing the apparatus 10 to the bone, the apparatus 10 further includes a plurality of attachment members 26. The attachment members 26 extend radially from the outer periphery of the body member 18 and include a bone screw hole 28. The bone screw hole 28 is used to provide means for receiving a suitable bone screw (not shown). The bone screw hole 28 is located centrally on the attachment members 26 and serves to secure the attachment members 26 to the bone upon receipt of the bone screw.

To provide means for securing the attachment members 26 at a plurality of different positions with respect to the body member 18, the apparatus 10 further includes a plurality of extension members 30. The extension members 30 are disposed generally concentric with respect to the body member 18 and initially extend in the direction generally perpendicular with respect to the radial centerline of the body member 18. The extension members 30 also are integrally formed with the body member 18 and mechanically communicate with the attachment members 26. In this regard, the body member 18 includes a plurality of hinge portions 32 which are able to be deformed upon movement of the extension members 30 with respect to the body member 18 as shown in FIG. 3. Accordingly, each of the attachment members 26 may be located at a variety of positions with respect to the body member 18 upon movement of the corresponding extension member 30 and deformation of the hinge portion 32.

Because the attachment members 26 may be located at a variety of positions with respect to the body member 18, the attachment members 26 can be suitably located on the bone so as to provide optimum positioning of the body member 18 with respect to the bone while also providing optimum positioning of the bone screws. The apparatus 10 may therefore be configured to the specific needs of each particular application. In addition, because the extension members 30 may be displaced from the body member 18, the apparatus 10 is able to accommodate for the growth of the patient. In this regard, as the patient grows, the skull enlarges which causes further displacement of the extension members 30 from the body member 18.

The method of using the present invention will now be described as used in neurosurgical and craniofacial procedures. It is to be understood, however, that the apparatus 10 may be used with other procedures as well. The apparatus 10 is first formed having the body member 18, at least one attachment member 26, as well as an extension member 30. After the apparatus 10 has been formed, the bone flap 12 is then prepared by drilling several burr holes through the cranial vault. After the burr holes have been drilled, osteotomies are made in the skull which connects the burr holes. The saw which is used to form the osteotomies may preferably have a nose guide which serves to avoid injuries to the dura mater. The bone flap 12 is then removed so as to provide access to the brain or to allow the surgeon to shape the bone flap.

After the procedures on the brain have been completed or the bone flap 12 has been shaped, the bone flap 12 is replaced in the skull 14 to cover the defect. The apparatus 10 is then centrally located over one of the burr holes. The surgeon then determines the desired position of the body member 18 with respect to the bone, as well as determines the desired position for the bone screws which will be used to secure the apparatus 10 to the bone. Several or all of the extension members 30 of the apparatus 10 may then be displaced from the body member 18 so as to provide the desired positioning of the attachment members 26 with respect to both the bone flap 12 and the skull 14. Suitable holes are then drilled in the bone flap 12 and the skull 14. Bone screws are then inserted through the holes in the attachment members 26 and into the holes in the bone flap 12 and the skull 14. It will be appreciated that the apparatus 10 does not require each of the attachment members 26 to receive a bone screw. Rather, the surgeon can select which of the attachment members 26 are to receive a bone screw to positionally secure the apparatus 10 to both the bone flap 12 as well as the skull 14. However, it will be understood that it is generally preferable to fill each of the holes in the attachment members 26 with bone screws.

The second preferred embodiment of the present invention will now be described with reference to FIG. 4. In this regard, like reference numerals will be used to identify similar structures as described with respect to the first preferred embodiment of the present invention. The apparatus 10 according to the second preferred embodiment of the present invention further includes a third plurality of elongated apertures 34. The third plurality of elongated apertures 34 are disposed generally concentric with respect to the body member 18, though at a distance further from the center of the body member 18 than the second plurality of elongated apertures 22. Each of the elongated apertures 34 includes a curved end portion 36 which is disposed at a distance which is closer to the outer periphery of the body member 18 than the remaining portion of the elongated apertures 34.

The portion of the body member 18 between the curved end portion 36 of the elongated apertures 34 and the outer periphery of the body member 18 is operable to form a latch portion 38. The latch portion 38 of the body member 18 serves to secure the extension member 30 to the body member 18 until it is desirable to displace the extension member 30 with respect to the body member 18. When it becomes desirable to displace the extension member 30 in this manner, the latch portion 38 of the body member 18 is severed so as to permit the extension member 30 to be moved with respect to the body member 18. Accordingly, the latch portion 38 provides additional support to the attachment member 26 when the latch portion 38 is not severed, yet permits the extension member 30 to be displaced so as to allow the attachment member 26 to be placed at a variety of locations when necessary by severing the latch portion 38. As will be appreciated by those skilled in the art, the method of using the apparatus 10 according to this preferred embodiment of the present invention is similar to that described above.

The third preferred embodiment of the present invention will now be described with reference to FIG. 5. In this regard, like numerals are used to identify similar elements as described with respect to the second preferred embodiment of the present invention. The apparatus 10 according to the third preferred embodiment of the present invention functions in a manner similar to that described with respect to the second preferred embodiment of the present invention. However, the third preferred embodiment does not include the first plurality of elongated apertures 20 as well as the second plurality of elongated apertures 22. Rather, the third preferred embodiment of the present invention includes a first plurality of circular apertures 40 as well as a second plurality of circular apertures 42. The first and second plurality of circular apertures 40 and 42 serve to provide for the flow of fluids through the apparatus 10. The first plurality of circular apertures 40 are concentrically disposed with respect to the body member 18 at a position relatively close to the center of the body member 18. The second plurality of circular apertures 42 are also concentrically disposed with respect to the body member 18 at a position between the first plurality of circular apertures 40 and the elongated apertures 34. As will be appreciated by those skilled in the art, the method of using the apparatus 10 according to this preferred embodiment of the present invention is similar to that described above.

The fourth preferred embodiment of the present invention will now be described with reference to FIG. 6. In this regard, like reference numerals will be used to identify similar features as described with respect to the second preferred embodiment of the present invention. The apparatus 10 according to the fourth preferred embodiment of the present invention does not include the third plurality of elongated apertures 34. Rather, the third preferred embodiment of the present invention includes a plurality of circular apertures 44. The plurality of circular apertures 44 are concentrically disposed with respect to the body member 18 and are disposed between the second plurality of elongated apertures 22 and the attachment members 26. The plurality of circular apertures 44 serve to facilitate the flow of fluid through the apparatus 10. As will be appreciated by those skilled in the art, the method of using the apparatus 10 according to this preferred embodiment of the present invention is similar to that described above. However, it will be understood that the apparatus 10 according to this embodiment does not have extension members which serves to allow the attachment members 26 to be oriented at a variety of positions with respect to the body member 18.

Those skilled in the art can now appreciate from the foregoing that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while the invention was described in connection with particular examples hereof, the true scope of the invention should not be so limited. For example, the present invention may be used with a variety of surgical procedures which may not necessarily involve neurosurgical and/or craniofacial procedures. In addition, the body member does not necessarily have to be substantially circular in configuration but may be of other shapes which are desirable for a particular application. While there are preferably five attachment members associated with each embodiment of the present invention, it will be understood that either greater or fewer attachment members may be present. In addition, the extension members may be of other suitable shapes and sizes which are desirable for a given application. Other modifications will become apparent to those skilled in the art.