Instrument guide for use with a surgical navigation system

An instrument guide system for use with a surgical navigation system, the instrument guide system comprising a handle assembly, an instrument attachment assembly, a shaft connecting the handle assembly to the instrument attachment assembly, an electromagnetic sensor assembly removably mounted within an opening in the handle assembly, and an instrument removably attachable within a bore of the instrument attachment assembly.

BACKGROUND OF THE INVENTION

This disclosure relates generally to image-guided surgery (or surgical navigation), and more particularly, to an instrument guide for use in spinal surgical navigation procedures with surgical navigation systems.

Surgical navigation systems track the precise location of surgical instruments in relation to multidimensional images of a patient's anatomy. Additionally, surgical navigation systems use visualization instruments to provide the surgeon with co-registered views of these surgical instruments with the patient's anatomy.

During surgical procedures, it is beneficial to be able to track the position and trajectory of a surgical instrument, such as a drill bit, into a surgical site on a patient's body in order to ensure that the instrument is directed at the appropriate point in the body. In order to better track the position and trajectory of an instrument entering a surgical site, the instruments are often used with tracked instrument guides. The tracked instrument guides typically include a sensor assembly attached to the handle of the instrument guide. The sensor assembly may communicate with a computer to provide navigation and visualization information of the instrument on a display superimposed on an image of the patient's anatomy in the surgical field of interest.

Instrument guides are used in spinal surgery often for complex cases requiring precision placement of instrumentation, for example in the cervical spine. The approaches are anterior and/or posterior for various indications and procedures. Due to these different approaches, different instrument guides are utilized during certain instrument insertion steps (drill, k-wire, tap, and screw) of a procedure. Instrument guides allow proper positioning of the drill hole and tap to ensure different degrees of convergence patterns of screws at pre-selected angles. Instrument guides also help prevent toggling of different size drills and taps, minimizing the chance of losing cortical or bony tissue that helps later to ensure good bone screw purchase. The instrument guides also work as a safety stop to prevent over-tapping and bi-cortical breech by ending at pre-selected depths.

Therefore, it is desirable to provide navigation and visualization of an instrument guide for instrumentation used in spinal surgery.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, an instrument guide apparatus comprising a handle assembly, the handle assembly including a docking station formed therein for receiving an electromagnetic sensor assembly therein, an instrument attachment assembly, and a shaft connecting the handle assembly to the instrument attachment assembly.

In another aspect, an instrument guide system for use with a surgical navigation system, the instrument guide system comprising a handle assembly, an instrument attachment assembly, a shaft connecting the handle assembly to the instrument attachment assembly, an electromagnetic sensor assembly removably mounted within an opening in the handle assembly, and an instrument removably attachable within a bore of the instrument attachment assembly.

In yet another aspect, a calibration instrument for use with an instrument guide system, the calibration instrument comprising a cylindrically shaped rod having an outer diameter, a proximal end with a pointed tip, and a distal end with a pointed tip; and an engagement mechanism located toward the distal end thereof for mounting the calibration instrument into the instrument guide system.

In still yet another aspect, a guide instrument for use with an instrument guide system, the guide instrument comprising a cylindrically shaped tube having a bore extending therethrough, the cylindrical shaped tube having an outer diameter, a proximal end, and a distal end; and an engagement mechanism located near the distal end thereof for mounting the guide instrument into the instrument guide system.

Various other features, objects, and advantages of the invention will be made apparent to those skilled in the art from the accompanying drawings and detailed description thereof.

DETAILED DESCRIPTION OF THE INVENTION

In spinal surgical procedures, access to the body is obtained through one or more small percutaneous incision, mini-incision or one larger incision. Surgical instruments and guides are inserted through these openings and directed to a region of interest within the body. This would typically include the anterior lumbar spine, the junction for the lumbosacral space and the anterior cervical spine. Direction of the surgical instruments and guides through the body is facilitated by navigation technology wherein the real-time location of a surgical instrument or guide is measured and virtually superimposed on an image of the region of interest. The image may be a pre-acquired image, or an image obtained in near real-time or real-time using known imaging technologies such as computed tomography (CT), magnetic resonance (MR), positron emission tomography (PET), ultrasound, X-ray, or any other suitable imaging technology, as well as any combinations thereof.

Referring now to the drawings,FIG. 1illustrates an exemplary schematic diagram of an embodiment of a surgical navigation system10. The surgical navigation system10includes at least one electromagnetic field generator12positioned proximate to a surgical field of interest14, at least one electromagnetic sensor16attached to a trackable instrument guide18to which a surgical instrument may be inserted, the at least one electromagnetic sensor16communicating with and receiving data from the at least one electromagnetic field generator12, a navigation apparatus24coupled to and receiving data from the at least one electromagnetic sensor16and the at least one electromagnetic field generator12, an imaging apparatus26coupled to the navigation apparatus24for performing imaging on a patient22in the surgical field of interest14, and a display28coupled to the navigation apparatus24for displaying imaging and tracking data from the imaging apparatus26and the navigation apparatus24.

In an exemplary embodiment, the at least one electromagnetic field generator12may be attached to a dynamic reference apparatus20that may be attached to the patient22in the surgical field of interest14. The at least one electromagnetic field generator12creates a local reference frame for the navigation apparatus24around the patient's anatomy.

The display28may be configured to show the real-time position and orientation of a model of the instrument guide18or surgical instrument inserted within the guide on a registered image of the patient's anatomy. The model of the instrument guide18or instrument may appear as a line rendering, a few simply shaded geometric primitives, or a realistic 3D model from a computer-aided design (CAD) file.

In an exemplary embodiment, the imaging apparatus26and the navigation apparatus24may be integrated into a single integrated imaging and surgical navigation system with integrated instrumentation and software.

The system10enables a surgeon to continually track the position and orientation of the instrument guide18or instrument during surgery. An electromagnetic field30is generated around the at least one electromagnetic field generator12. The at least one electromagnetic sensor16detects the electromagnetic field30generated by the at least one electromagnetic field generator12attached to the dynamic reference apparatus20. The at least one electromagnetic sensor16may be an electromagnetic field receiver. The electromagnetic field receiver may be a receiver array including at least one coil or at least one coil pair and electronics for digitizing magnetic field measurements detected by the receiver array. The at least one electromagnetic field generator12may be an electromagnetic field transmitter. The electromagnetic field transmitter may be a transmitter array including at least one coil or at least one coil pair. It should, however, be appreciated that according to alternate embodiments the dynamic reference apparatus20may include at least one electromagnetic field receiver attached thereto and the instrument guide18may include at least one electromagnetic field transmitter attached thereto.

The magnetic field measurements can be used to calculate the position and orientation of the instrument guide18or instrument according to any suitable method or system, After the magnetic field measurements are digitized using electronics, the digitized signals are transmitted from the at least one electromagnetic sensor16to the navigation apparatus24. The digitized signals may be transmitted from the at least one electromagnetic sensor16to the navigation apparatus24using wired or wireless communication protocols and interfaces. The digitized signals received by the navigation apparatus24represent magnetic field information detected by the at least one electromagnetic sensor16. The digitized signals are used to calculate position and orientation information of the instrument guide18or instrument. The position and orientation information is used to register the location of the instrument guide18or instrument to acquired imaging data from the imaging apparatus26. The position and orientation data is visualized on the display28, showing in real-time the location of the instrument guide18or instrument on pre-acquired or real-time images from the imaging apparatus26. The acquired imaging data from the imaging apparatus26may include CT imaging data, MR imaging data, PET imaging data, ultrasound imaging data, X-ray imaging data, or any other suitable imaging data, as well as any combinations thereof. In addition to the acquired imaging data from various modalities, real-time imaging data from various real-time imaging modalities may also be available.

The navigation apparatus24is illustrated conceptually and may be implemented using any combination of dedicated hardware boards, digital signal processors, field programmable gate arrays, and processors. Alternatively, the navigation apparatus24may be implemented using an off-the-shelf computer with a single processor or multiple processors, with the functional operations distributed between processors. As an example, it may be desirable to have a dedicated processor for position and orientation calculations as well as a processor for visualization operations. The navigation apparatus24may be an electromagnetic navigation system utilizing electromagnetic navigation technology. However, other tracking or navigation technologies may be used.

FIG. 2illustrates an exemplary block diagram of an embodiment of a surgical navigation system100. The surgical navigation system100is illustrated conceptually as a collection of modules, but may be implemented using any combination of dedicated hardware boards, digital signal processors, field programmable gate arrays, and processors. Alternatively, the modules may be implemented using an off-the-shelf computer with a single processor or multiple processors, with the functional operations distributed between the processors. As an example, it may be desirable to have a dedicated processor for position and orientation calculations as well as a dedicated processor for visualization operations. As a further option, the modules may be implemented using a hybrid configuration in which certain modular functions are performed using dedicated hardware, while the remaining modular functions are performed using an off-the-shelf computer. In the embodiment shown inFIG. 2, the navigation apparatus24includes a single computer32having a processor34, a system controller36and memory38. The operations of the modules and other components of the navigation apparatus24may be controlled by the system controller36.

The surgical navigation system100includes at least one electromagnetic field generator12that is coupled to a navigation interface40. The at least one electromagnetic field generator12generates at least one electromagnetic field that is detected by at least one electromagnetic field sensor16. The navigation interface40receives digitized signals from at least one electromagnetic sensor16. The navigation interface40includes at least one Ethernet port. The at least one Ethernet port may be provided, for example, with an Ethernet network interface card or adapter. However, according to various alternate embodiments, the digitized signals may be transmitted from the at least one electromagnetic sensor16to the navigation interface40using alternative wired or wireless communication protocols and interfaces.

The digitized signals received by the navigation interface40represent magnetic field information from the at least one electromagnetic field generator12detected by the at least one electromagnetic sensor16. In the embodiment illustrated inFIG. 2, the navigation interface40transmits the digitized signals to a tracker module50over a local interface45. The tracker module50calculates position and orientation information based on the received digitized signals. This position and orientation information provides a location of a surgical instrument or implant.

The tracker module50communicates the position and orientation information to a navigation module60over a local interface45. As an example, this local interface45is a Peripheral Component Interconnect (PCI) bus. However, according to various alternate embodiments, equivalent bus technologies may be substituted.

Upon receiving the position and orientation information, the navigation module60is used to register the location of the surgical instrument or implant to acquired patient data. In the embodiment illustrated inFIG. 2, the acquired patient data is stored on a data storage device70. The acquired patient data may include computed tomography data, magnetic resonance data, positron emission tomography data, ultrasound data, X-ray data, or any other suitable data, as well as any combinations thereof. By way of example only, the data storage device70is a hard disk drive, but other suitable storage devices may be used.

The acquired patient data is loaded into memory38from the data storage device70. The acquired patient data is retrieved from the data storage device70by a data storage controller75. The navigation module60reads from memory38the acquired patient data. The navigation module60registers the location of the instrument guide to acquired patient data, and generates image data suitable to visualize the patient image data and a representation of the instrument guide. The image data is transmitted to a display controller55over a local interface45. The display controller55is used to output the image data to display28.

In another exemplary embodiment, the surgical navigation system100may include an imaging apparatus26coupled to an imaging interface65for receiving real-time imaging data. The imaging data is processed in an imaging module80. The imaging apparatus26provides the ability to display real-time position and orientation information of an instrument guide on the display28.

While one display28is illustrated in the embodiment inFIG. 2, alternate embodiments may include various display configurations. Various display configurations may be used to improve operating room ergonomics, display different views, or display information to personnel at various locations.

FIGS. 3,4and5illustrate various views of an exemplary embodiment of an instrument guide apparatus102. The instrument guide apparatus102comprises a handle assembly104, an instrument attachment assembly106, and a shaft108connecting the handle assembly104to the instrument attachment assembly106.

The handle assembly104includes a handle body110and a handle stem112. The handle body110includes an open top113, two opposed sidewalls115,117and a bottom wall119. The open top113, two opposed sidewalls115,117and bottom wall119forms a docking station114for mounting an electromagnetic sensor assembly therein. The docking station114includes an opening116for receiving an electromagnetic sensor assembly therein, a locking member118at one end of the opening116for locking the electromagnetic sensor assembly in place, and an engagement member120at the opposite end thereof for keeping the electromagnetic sensor assembly engaged within the opening116. The electromagnetic sensor assembly is secured between the locking member118and the engagement member120within the opening116. The handle body110also includes a flexible switch member132in the bottom wall119thereof that functions as a push button switch. The flexible switch member132includes a fixed end133attached to a structural member121of the handle body110and a free end135, opposite the fixed end133, that may be pushed in by a user to activate a feature in the surgical navigation system software as further described below. Once the free end135of the flexible switch member132has been pushed in and released by a user, the free end135returns to its original position.

The handle stem112extends from the handle body110to the shaft108. The shaft108extends from the end of the handle stem112through an opening122in a cylindrical member124of the instrument attachment assembly106. The end126of the shaft108extends up through the opening122and includes a tab128to secure and prevent a calibration or guide instrument inserted within a central bore130of the cylindrical member124from rotating.

The instrument attachment assembly106includes the cylindrical member124having a central bore130extending therethrough and a fastening member134extending around an outer surface138of the cylindrical member124. The cylindrical member124receives a calibration or guide instrument within its central bore130, the instrument extending through the central bore130.

The cylindrical member124has an inner surface136and an outer surface138. The inner surface136forming the central bore130, and the outer surface138having a lip140extending around an outer circumference of an upper portion142thereof to prevent the fastening member134from sliding off the upper portion142of the cylindrical member124. The shaft108extending into the opening122on a lower portion144of the cylindrical member124prevents the fastening member134from sliding off the lower portion144thereof. The fastening member134is thus, movable along the outer surface138of the cylindrical member124between the shaft108and the lip140.

The fastening member134has a flange150extending around the circumference of one of its open ends152and extending inwardly to engage the lip140extending around the outer surface138of the upper portion142of cylindrical member124. The fastening member134includes threads on its inner surface for securing a calibration or guide instrument within the central bore130of the cylindrical member124. The fastening member134is used for locking and releasing a calibration or guide instrument to and from the cylindrical member124.

FIG. 6illustrates an enlarged view of an exemplary embodiment of the handle assembly104of the instrument guide apparatus102. As stated above, the handle assembly104includes a handle body110and a handle stem112. The handle body110includes an open top113, two opposed sidewalls115,117and a bottom wall119. The open top113, two opposed sidewalls115,117and bottom wall119forms a docking station114for mounting an electromagnetic sensor assembly therein. The electromagnetic sensor assembly enabling tracking and navigation of the instrument guide. The docking station114includes an opening116for receiving an electromagnetic sensor assembly therein, a locking member118at one end of the opening116for locking the electromagnetic sensor assembly in place, and an engagement member120at the opposite end thereof for keeping the electromagnetic sensor assembly engaged within the opening116. The electromagnetic sensor assembly is secured between the locking member118and the engagement member120within the opening116. The handle body110also includes a flexible switch member132in the bottom wall119thereof that functions as a push button switch. The flexible switch member132includes an inner surface137and an outer surface139. The flexible switch member132also includes a fixed end133attached to a structural member121of the handle body110and a free end135, opposite the fixed end133, that may be pushed in by a user to activate a feature in the surgical navigation system software as further described below. Once the free end135of the flexible switch member132has been pushed in and released by a user, the free end135returns to its original position.

The locking member118is flexible and includes a tab154to lock and release the electromagnetic sensor assembly in place within the opening116of the docking station114. The locking member118and tab154are bent back towards the handle stem112when installing an electromagnetic sensor assembly with the tab154engaging a portion of the electromagnetic sensor assembly to lock it in place. To remove the electromagnetic sensor assembly, the locking member118and tab154are bent back again towards the handle stem112to release the tab154from the portion of the electromagnetic sensor assembly so that it may be pulled out. The engagement member120is a spring-like member or is made from a flexible spring-like material that deforms when an electromagnetic sensor assembly is installed, and pushes against the electromagnetic sensor assembly, pushing it towards the locking member118and tab154to hold the electromagnetic sensor assembly in place. The engagement member120deforms when pressure or force is applied against it and returns to its original shape when no pressure or force is applied against it.

The handle body110also includes a plurality of cavities156,157formed in structural members121,123in the bottom of opening116of docking station114. These cavities156,157are designed to be populated with magnets (not shown) and located adjacent to Hall effect sensor circuitry on an electromagnetic sensor assembly when it is installed in opening116of docking station114. The Hall effect sensor circuitry detects the presence of magnets. A magnet may or may not be installed in each cavity. The presence or lack of a magnet in each cavity provides a bit pattern (magnet, no magnet) that is detected by the Hall effect sensor circuitry and interpreted by software in the surgical navigation system to determine the specific instrument or guide instrument being used. Each surgical instrument or guide instrument is associated with a particular bit pattern in the software, so that the software can identify the particular instrument or guide instrument being used. The presence (1) or no presence (0) of a magnet provides the bit pattern (magnet (1), no magnet (0)) to activate the Hall effect sensor circuitry, enabling the surgical navigation system to recognize and identify the type of instrument or guide instrument being used.

The flexible switch member132includes a cavity158formed in the inner surface137of free end135at the bottom of opening116of docking station114. The cavity58is designed to be populated with a magnet (not shown) and located a distance from Hall effect sensor circuitry on an electromagnetic sensor assembly when it is installed in opening116of docking station114. In this position, the magnet in cavity158is too far away from the Hall effect sensor circuitry on the electromagnetic sensor assembly so that it does not sense the magnet. The magnet in cavity158is farther away from the Hall effect sensor circuitry on the electromagnetic sensor assembly than the magnets in cavities156and157would be. When a user pushes in free end135of flexible switch member132towards the Hall effect sensor circuitry on the electromagnetic sensor assembly, the magnet in cavity158moves closer to the Hall effect sensor circuitry, which detects the magnet and activates a feature in the navigation system software. This feature could be to freeze the virtual representation and virtual trajectory line of the instrument guide shown on the display, or any other feature. For example, a second push of free end135of flexible switch member132could be to clear the virtual trajectory line of the instrument guide shown on the display.

FIG. 7illustrates an exemplary embodiment of a calibration instrument160attachable to the instrument guide apparatus102. The calibration instrument160is a cylindrically shaped rod with two pointed ends. The calibration instrument160includes a proximal end162that tapers to a point166and a distal end164that tapers to a point168. The calibration instrument160includes a front pointed tip166and a rear pointed tip168used in a calibration procedure. The calibration instrument160further includes, an engagement mechanism170located toward the distal end164thereof. The engagement mechanism170includes an engagement cylinder172having an outer diameter greater than the outer diameter of the cylindrically shaped rod. The engagement cylinder172includes at least one flat groove174, or other keying feature, at one end thereof and a radially extending disk176at the opposite end thereof. The at least one flat groove174is designed to mate with the tab128of the end126of shaft108to secure and prevent the calibration instrument from rotating. The disk176having an outer circumference surface178that is threaded for engaging the threads on the inner surface of fastening member134on the instrument attachment assembly106.

In operation, the distal end164of the calibration instrument160is inserted into the central bore130of the cylindrical member124of the instrument attachment assembly106until the tab128engages the flat groove174. The fastening member134is then brought up around the disk176and tightened to secure the calibration instrument160in place within the instrument attachment assembly106.

To ensure the virtual instrument image accuracy, an instrument guide system is calibrated with calibration instruments160, one for each guide instrument length. Therefore, there is a set of calibration instruments160, each having a different length to correspond to the different lengths of the guide instruments to be used in a surgical procedure. Each calibration instrument160can be easily locked and released to and from the instrument attachment assembly106using the same fastening features described above.

FIG. 8illustrates an exemplary embodiment of a trackable instrument guide system180with a calibration instrument160and an electromagnetic sensor assembly190attached to the instrument guide apparatus102. The instrument guide system180comprises a handle assembly104, an instrument attachment assembly106, a shaft108connecting the handle assembly104to the instrument attachment assembly106, an electromagnetic sensor assembly190removably mounted within a docking station114of the handle assembly104, and a calibration instrument160removably attachable within the central bore130of the instrument attachment assembly106. The calibration instrument160may be from a set of calibration instruments having different lengths that correspond to the different lengths of guide instruments. The instrument guide system180is intended for multiple uses in surgical procedures to guide instrumentation with surgical navigation.

The electromagnetic sensor assembly190is configured to receive electromagnetic signals as part of the surgical navigation system. For example, an electromagnetic field generator is located in a fixed position relative to a surgical field of interest. The electromagnetic field generator generates an electromagnetic field to be received by an electromagnetic sensor of the electromagnetic sensor assembly190. The electromagnetic sensor and the electromagnetic field generator are coupled to a computer such that the computer may calculate and determine the position, orientation and trajectory of the electromagnetic sensor relative to the electromagnetic field generator. The computer provides visualization and navigation of the instrument guide system180for instrumentation used in various surgical procedures.

In order to prepare the instrument guide system180for use during a surgical procedure and to ensure virtual instrument image accuracy, the instrument guide system180is first calibrated with calibration instruments160, one for each guide instrument length being used. The calibration instrument160is installed within the central bore130of the instrument attachment assembly106. The positions of the tips166,168of the calibration instrument160are located relative to the electromagnetic sensor assembly190by touching the front tip166to a reference point of known location and touching the rear tip168to a reference point of known location. The reference point of known location may be the dynamic reference apparatus20. The position and trajectory of the calibration instrument160relative to the electromagnetic sensor assembly190is then stored in the computer of the surgical navigation system.

FIG. 9illustrates an exemplary embodiment of a guide instrument210attachable to the instrument guide apparatus102. The guide instrument210is generally cylindrical in shape and includes a bore212extending therethrough. The bore212has an inner diameter of a size appropriate to accommodate a drill bit, guide pin, guidewire, k-wire, awl, tap, probe, screw or other insertable instrument. The guide instrument210includes a proximal end214and a distal end216. The guide instrument210further includes an engagement mechanism218located near the distal end216thereof. The engagement mechanism218includes an engagement cylinder220having an outer diameter greater than the outer diameter of the guide instrument210. The engagement cylinder220includes at least one flat groove222, or other keying feature, at one end thereof and a radially extending disk224at the opposite end thereof. The at least one flat groove222is designed to mate with the tab128of the end126of shaft108to secure and prevent the guide instrument from rotating. The disk224having an outer circumference surface226that is threaded for engaging the thread on the inner surface of fastening member134on the instrument attachment assembly106.

The guide instrument210may be designed for multiple uses and made of a material typically used for multiple use surgical instruments, or designed for a single use and made of a disposable radiolucent material.

In operation, the distal end216of the guide instrument210is inserted into the central bore130of the cylindrical member124of the instrument attachment assembly106until the tab128engages the flat groove222. The fastening member134is then brought up around the disk224and tightened to secure the guide instrument210in place within the instrument attachment assembly106.

The guide instruments210may vary in size (outer and inner diameters) and length (some have adjustable lengths for adjusting depth), and also by shape (some are single barreled and some are double barreled). Therefore, there is a set of guide instruments210, each having different inner diameters, outer diameters, and lengths to correspond to the different surgical instruments to be used in a surgical procedure. Each guide instrument210can be easily locked and released to and from the instrument attachment assembly106using the same fastening features described above.

FIG. 10illustrates an exemplary embodiment of a trackable instrument guide system230with a guide instrument210and an electromagnetic sensor assembly190attached to the instrument guide apparatus102. The instrument guide system230comprises a handle assembly104, an instrument attachment assembly106, a shaft108connecting the handle assembly104to the instrument attachment assembly106, an electromagnetic sensor assembly190removably mounted within a docking station114of the handle assembly104, and a guide instrument210removably attachable within the central bore130of the instrument attachment assembly106. The guide instrument210may be from a set of guide instruments having different inner diameters, outer diameters, and lengths. The instrument guide system230is configured to receive a surgical instrument within the bore212of the guide instrument210. The instrument guide system230is intended for multiple uses in surgical procedures to guide instrumentation with surgical navigation.

The electromagnetic sensor assembly190is configured to receive electromagnetic signals as part of the surgical navigation system. For example, an electromagnetic field generator is located in a fixed position relative to a surgical field of interest. The electromagnetic field generator generates an electromagnetic field to be received by an electromagnetic sensor on the electromagnetic sensor assembly190. The electromagnetic sensor and the electromagnetic field generator are coupled to a computer such that the computer may calculate and determine the position, orientation and trajectory of the electromagnetic sensor relative to the electromagnetic field generator. The computer provides visualization and navigation of the instrument guide system230for instrumentation used in various surgical procedures.

Once the guide instrument is properly calibrated and trackable, the surgeon inserts a desired instrument into the guide instrument. The position of the instrument is fixed and known relative to the electromagnetic sensor. The electromagnetic sensor communicates with the computer in the surgical navigation system such that the computer can calculate, determine, and show on a display, the position and trajectory of the guide instrument relative to the patient's anatomy. Thus, the surgeon can track the movement of the guide instrument relative to the image on the display during surgery. Because the position of the instrument is fixed and known relative to the electromagnetic sensor, the computer can calculate, determine and display the position of the proximal end of the instrument relative to the patient's anatomy.

FIGS. 11A and 11Billustrate an exemplary embodiment of a guide instrument240attachable to the instrument guide apparatus102. The guide instrument240is generally cylindrical in shape and includes a first bore242extending therethrough and a second bore244extending therethrough, the second bore244being adjacent to first bore242. The first bore242has an inner diameter of a size appropriate to accommodate a drill bit, guide pin, guidewire, k-wire, awl, tap, probe, screw or other insertable instrument. The second bore244has an inner diameter of a size appropriate to accommodate a catheter, endoscope, fiberscope, video endoscope or other insertable instrument. For example, the second bore244could be used to accept a catheter with irrigation and aspiration capabilities, a high intensity fiber optic light cable, or a rigid or flexible scope. The guide instrument240includes a proximal end246and a distal end248. The guide instrument240further includes an engagement mechanism250located near the distal end248thereof. The engagement mechanism250includes an engagement cylinder252having an outer diameter greater than the outer diameter of the guide instrument240. The engagement cylinder252includes at least one flat groove254, or other keying feature, at one end thereof and a radially extending disk256at the opposite end thereof. The at least one flat groove254is designed to mate with the tab128of the end126of shaft108to secure and prevent the guide instrument from rotating. The disk256having an outer circumference surface258that is threaded for engaging the thread on the inner surface of fastening member134on the instrument attachment assembly106.

The guide instrument240may be designed for multiple uses and made of a material typically used for multiple use surgical instruments, or designed for a single use and made of a disposable radiolucent material.

In operation, the distal end248of the guide instrument240is inserted into the central bore130of the cylindrical member124of the instrument attachment assembly106until the tab128engages the flat groove254. The fastening member134is then brought up around the disk256and tightened to secure the guide instrument240in place within the instrument attachment assembly106.

FIG. 12illustrates an exemplary embodiment of a trackable instrument guide system260with a guide instrument240and an electromagnetic sensor assembly190attached to the instrument guide apparatus102. The instrument guide system260comprises a handle assembly104, an instrument attachment assembly106, a shaft108connecting the handle assembly104to the instrument attachment assembly106, an electromagnetic sensor assembly190removably mounted within a docking station114of the handle assembly104, and a guide instrument240removably attachable within the central bore130of the instrument attachment assembly106. The instrument guide system260is configured to receive a first surgical instrument (not shown) within the first bore242of the guide instrument240and a second surgical instrument262within the second bore244of the guide instrument240. The instrument guide system260is intended for multiple uses in surgical procedures to guide instrumentation with surgical navigation. The second bore244may accept a second surgical instrument262, such as a catheter, endoscope, fiber optic light cable, fiberscope or video endoscope, extending therethrough.

In an embodiment, the second bore244may accept a high intensity fiber optic light cable through which a high intensity light is beamed to brilliantly illuminate the patient's anatomy in the surgical field of interest. The high intensity fiber optic light cable may be integrated with a light port and endoscopic telescope to visualize the patient's anatomy in the surgical field of interest for display on the surgical navigation system's display. This endoscopic view may be mixed with 2D fluoro images, 3D fluoro images, CT images, MR images, PET images, ultrasound images, or fused together in the case of advanced percutaneous MIS procedures.

The second surgical instrument262, such as a catheter, endoscope, fiber optic light cable, fiberscope, or video endoscope, extends from the second bore244and distal end248of the guide instrument240across the handle assembly104. The handle assembly104may include at least one clip264to hold the second surgical instrument262against the handle assembly104. The catheter, endoscope, fiber optic light cable, fiberscope, or video endoscope262may also be attached to a cable266from the electromagnetic sensor assembly190with a fastener268. The catheter, endoscope, fiber optic light cable, fiberscope, or video endoscope may be coupled to a video and/or light source unit (not shown).

These instrument guides210,240and trackable instrument guide systems230,260may be used in various surgical procedures including abdominal, cervical, thoracic, lumbar, and extremity procedures.

For simple and complex surgical applications the navigated instrument guide system provides new technology of real-time virtual instrument visualization on a computer screen. The benefits of navigation are less x-ray radiation explosion to the surgeon and the patient, less time for fluoroscopic manipulations, up to four simultaneous multi-planar x-ray guidance views versus single view, enhanced precision of instrument placement, stronger purchase for screw placement, ability to save trajectories in all views, capability to project forward a virtual trajectory from the guide tip and ability to estimate instrument depth.

It should be appreciated that according to alternate embodiments, the at least one electromagnetic sensor may be an electromagnetic receiver, an electromagnetic generator (transmitter), or any combination thereof. Likewise, it should be appreciated that according to alternate embodiments, the at least one electromagnetic field generator may be an electromagnetic receiver, an electromagnetic transmitter or any combination of an electromagnetic field generator (transmitter) and an electromagnetic receiver.

Several embodiments are described above with reference to drawings. These drawings illustrate certain details of specific embodiments that implement the systems, methods and programs of the invention. However, the drawings should not be construed as imposing on the invention any limitations associated with features shown in the drawings. This disclosure contemplates methods, systems and program products on any machine-readable media for accomplishing its operations. As noted above, the embodiments of the may be implemented using an existing computer processor, or by a special purpose computer processor incorporated for this or another purpose or by a hardwired system.

An exemplary system for implementing the overall system or portions of the disclosure might include a general purpose computing device in the form of a computer, including a processing unit, a system memory, and a system bus that couples various system components including the system memory to the processing unit. The system memory may include read only memory (ROM) and random access memory (RAM). The computer may also include a magnetic hard disk drive for reading from and writing to a magnetic hard disk, a magnetic disk drive for reading from or writing to a removable magnetic disk, and an optical disk drive for reading from or writing to a removable optical disk such as a CD ROM or other optical media. The drives and their associated machine-readable media provide nonvolatile storage of machine-executable instructions, data structures, program modules and other data for the computer.

Those skilled in the art will appreciate that the embodiments disclosed herein may be applied to the formation of any surgical navigation system. Certain features of the embodiments of the claimed subject matter have been illustrated as described herein, however, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. Additionally, while several functional blocks and relations between them have been described in detail, it is contemplated by those of skill in the art that several of the operations may be performed without the use of the others, or additional functions or relationships between functions may be established and still be in accordance with the claimed subject matter. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments of the claimed subject matter.