Instrumentation and method for mounting a surgical navigation reference device to a patient

#The present invention relates generally to the field of surgical instrumentation and methods that utilize image navigation systems to indicate and track the relative position of various anatomical body parts and/or surgical instruments during medical and surgical procedures, and more specifically relates to instrumentation and methods for percutaneously mounting a surgical navigation reference device to a patient.

#Image navigation technology has been developed to indicate and track the relative position of various body parts and surgical instrumentation and implants during medical and surgical procedures. Image navigation systems typically utilize scans obtained either prior to or during a medical or surgical procedure to generate two-dimensional or three-dimensional images of various parts of the body. Such images aid the surgeon in manipulating and guiding surgical instruments, equipment and/or implants during various medical or surgical procedures. Interest in image navigation technology has increased as a result of recent advances in scanning technology, particularly with regard to technological advancements in devices that use computers to generate three-dimensional images, such as computed tomography (CT) or magnetic resonance imaging (MRI).

#In the past, use of image navigation technology has been primarily directed to applications involving image guidance systems relating to the cranium. In such applications, the skull provides a convenient reference point for rigid attachment of an image navigation reference device, such as, for example, a surgical navigation reference frame. Recently, image navigation technology has been applied to other areas of the body including the spinal column. Surgical procedures involving the spinal column may be used, for example, to stabilize and/or fuse portions of the spine or to correct various spinal deformities or degenerative conditions. A number of surgical navigation systems have been developed for specific application to surgical procedures involving the spinal column. U.S. Pat. No. 6,226,548 to Foley et al. discloses one such system. A similar system is disclosed in U.S. Pat. No. 6,236,875 to Bucholz et al.

#FIG. 1 is a top view of the back of a patient lying in a prone position, illustrating the formation of a surgical incision above the lumbar region of the spinal column to accommodate a prior art method and apparatus for mounting a surgical navigation reference device to the patient's spinal column.

#FIG. 2 is a side view of the spinal column of the patient illustrated in FIG. 1, illustrating the clamping of a surgical navigation reference device to the spinous process of a vertebra.

#FIG. 3 is a top view of a cannula according to one embodiment of the present invention for use in association with the mounting of a surgical navigation reference device to a patient.

#For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation on the scope of the invention is hereby intended, and that alterations and further modifications in the illustrated devices and further applications of the principles of the invention as illustrated herein are contemplated as would normally occur to one skilled in the art to which the invention relates.

#Referring to FIGS. 3-8, shown therein is surgical instrumentation according to one form of the present invention for use in association with the percutaneous mounting of a surgical navigation reference device to a patient. Although the instrumentation and methods illustrated and described herein are directed to surgical procedures involving the spinal column, it should be understood that applications of the present invention may extend to surgical procedures outside of the spinal field, including surgical procedures involving the cranium, other types of bones, and/or other anatomical components.

#Referring specifically to FIGS. 3 and 4, shown therein is a cannula 50 according to one embodiment of the present invention. The cannula 50 extends along a longitudinal axis L and is generally comprised of an elongate tube 52 and a coupling mechanism 54. The elongate tube 52 defines a passage 56 formed entirely therethrough and extending generally along the longitudinal axis L. As will be discussed in further detail below, the axial passage 56 provides a percutaneous passageway or portal for insertion of a bone anchor into the patient for subsequent anchoring to bone. Although the cannula tube 52 is illustrated as having a cylindrical configuration, it should be understood that other shapes and configurations are also contemplated as falling within the scope of the invention. As will also be discussed in further detail below, the coupling mechanism 54 is adapted for engagement with an image navigation reference device to mount the image navigation reference device in a substantially fixed position relative to the patient's bone.