US20060009780A1 - Percutaneous registration apparatus and method for use in computer-assisted surgical navigation - Google Patents

Abstract

An apparatus and procedures for percutaneous placement of surgical implants and instruments such as, for example, screws, rods, wires and plates into various body parts using image guided surgery. An apparatus for use with a surgical navigation system, an attaching device rigidly connected to a body part, such as the spinous process of a vertebrae, with an identification superstructure rigidly but removably connected to the attaching device. This identification superstructure, for example, is a reference arc and fiducial array which accomplishes the function of identifying the location of the superstructure, and, therefore, the body part to which it is fixed, during imaging by CAT scan or MRI, and later during medical procedures.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 10/423,332 filed on Apr. 24, 2003; which is a reissue of 09/148,498 filed Sep. 4, 1998 which is now U.S. Pat. No. 6,226,548 issued on May 1, 2001; which claims rights under 35 U.S.C. §119 on provisional application No. 60/059,915, filed on Sep. 24, 1997. The disclosures of the above applications are incorporated herein by reference.
FIELD
• The present teachings relate generally to guiding, directing, or navigating instruments or implants in a body percutaneously, in conjunction with systems that use and generate images during medical and surgical procedures, which images assist in executing the procedures and indicate the relative position of various body parts, surgical implants, and instruments. In particular the teachings relate to apparatus and minimally invasive procedures for navigating instruments and providing surgical implants percutaneously in the spine, for example, to stabilize the spine, correct deformity, or enhance fusion in conjunction with a surgical navigation system for generating images during medical and surgical procedures.
BACKGROUND
• Typically, spinal surgical procedures used, for example, to provide stabilization, fusion, or to correct deformities, require large incisions and substantial exposure of the spinal areas to permit the placement of surgical implants such as, for example, various forms of screws or hooks linked by rods, wires, or plates into portions of the spine. This standard procedure is invasive and can result in trauma, blood loss, and post operative pain. Alternatively, fluoroscopes have been used to assist in placing screws beneath the skin. In this alternative procedure at least four incisions must be made in the patient's back for inserting rods or wires through previously inserted screws. However, this technique can be difficult in that fluoroscopes only provide two-dimensional images and require the surgeon to rotate the fluoroscope frequently in order to get a mental image of the anatomy in three dimensions. Fluoroscopes also generate radiation to which the patient and surgical staff may become over exposed over time. Additionally, the subcutaneous implants required for this procedure may irritate the patient. A lever arm effect can also occur with the screws that are not connected by the rods or wires at the spine. Fluoroscopic screw placement techniques have traditionally used rods or plates that are subcutaneous to connect screws from vertebra to vertebra. This is due in part to the fact that there is no fluoroscopic technique that has been designed which can always adequately place rods or plates at the submuscular region (or adjacent to the vertebrae). These subcutaneous rods or plates may not be well tolerated by the patient. They also may not provide the optimal mechanical support to the spine because the moment arm of the construct can be increased, thereby translating higher loads and stresses through the construct.
• A number of different types of surgical navigation systems have been described that include indications of the positions of medical instruments and patient anatomy used in medical or surgical procedures. For example, U.S. Pat. No. 5,383,454 to Bucholz; PCT Application No. PCT/US94/04530 (Publication No. WO 94/24933) to Bucholz; and PCT Application No. PCT/US95/12894 (Publication No. WO 96/11624) to Bucholz et al., the entire disclosures of which are incorporated herein by reference, disclose systems for use during a medical or surgical procedure using scans generated by a scanner prior to the procedure. Surgical navigation systems typically include tracking means such as, for example, an LED array on the body part, LED emitters on the medical instruments, a digitizer to track the positions of the body part and the instruments, and a display for the position of an instrument used in a medical procedure relative to an image of a body part.
• Bucholz et al. WO 96/11624 is of particular interest, in that it identifies special issues associated with surgical navigation in the spine, where there are multiple vertebral bodies that can move with respect to each other. Bucholz et al. describes a procedure for operating on the spine during an open process where, after imaging, the spinous process reference points may move with respect to each other. It also discloses a procedure for modifying and repositioning the image data set to match the actual position of the anatomical elements. When there is an opportunity for anatomical movement, such movement degrades the fidelity of the pre-procedural images in depicting the intra-procedural anatomy. Therefore, additional innovations are desirable to bring image guidance to the parts of the body experiencing anatomical movement.
• Furthermore, spinal surgical procedures are typically highly invasive. There is, thus, a need for more minimally invasive techniques for performing these spinal procedures, such as biopsy, spinal fixation, endoscopy, spinal implant insertion, fusion, and insertion of drug delivery systems, by reducing incision size and amount. One such way is to use surgical navigation equipment to perform procedures percutaneously, that is beneath the skin. To do so by means of surgical navigation also requires apparatus that can indicate the position of the spinal elements, such as, for example the vertebrae, involved in the procedure relative to the instruments and implants being inserted beneath the patient's skin and into the patient's spine. Additionally, because the spinal elements naturally move relative to each other, the user requires the ability to reorient these spinal elements to align with earlier scanned images stored in the surgical navigation system computer, to assure the correct location of those elements relative to the instruments and implants being applied or inserted percutaneously.
• In light of the foregoing, there is a need in the art for apparatus and minimally invasive procedures for percutaneous placement of surgical implants and instruments in the spine, reducing the size and amount of incisions and utilizing surgical navigation techniques.
SUMMARY
• Accordingly, the present teachings are directed to apparatus and procedures for percutaneous placement of surgical implants and instruments such as, for example, screws, rods, wires and plates into various body parts using image guided surgery. Various embodiments are directed to apparatus and procedures for the percutaneous placement of surgical implants and instruments into various elements of the spine using image guided surgery.
• To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, an apparatus for use with a surgical navigation system and comprises an attaching device rigidly connected to a body part, such as the spinous process of a vertebrae, with an identification superstructure rigidly but removably connected to the attaching device. This identification superstructure is a reference arc and fiducial array, which accomplishes the function of identifying the location of the superstructure, and, therefore, the body part to which it is fixed, during imaging by CAT scan or MRI, and later during medical procedures.
• According to various embodiments, the attaching device is a clamp with jaws and sharp teeth for biting into the spinous process.
• According to various embodiments, the fixture is a screw, having a head, wherein the screw is implanted into the spinous process and a relatively rigid wire is attached to the head of the screw and also implanted into the spinous process at an angle to the axis of the screw to prevent the screw from rotating in either direction.
• According to various embodiments, the superstructure includes a central post, and a fiducial array and a reference arc rigidly but removably attached to the central post. The fiducial array is composed of image-compatible materials, and includes fiducials for providing a reference point, indicating the position of the array, which are rigidly attached to the fiducial array, composed of, for example titanium or aluminum spheres. The reference arc includes emitters, such as, for example Light Emitting Diodes (“LEDs”), passive reflective spheres, or other tracking means such as acoustic, magnetic, electromagnetic, radiologic, or micropulsed radar, for indicating the location of the reference arc and, thus, the body part it is attached to, during medical procedures.
• According to various embodiments, a method for monitoring the location of an instrument, surgical implants and the various portions of the body, for example, vertebrae, to be operated on in a surgical navigation system comprising the steps of: attaching a fixture to the spinous process; attaching a superstructure including a fiducial array with fiducials and a reference arc to the fixture; scanning the patient using CT, MRI or some other three-dimensional method, with fiducial array rigidly fixed to patient to identify it on the scanned image; and thereafter, in an operating room, using image-guided technology, touching an image-guided surgical pointer or other instrument to one or more of the fiducials on the fiducial array to register the location of the spinal element fixed to the array and emitting an audio, visual, radiologic, magnetic or other detectable signal from the reference arc to an instrument such as, for example, a digitizer or other position-sensing unit, to indicate changes in position of the spinal element during a surgical procedure, and performing a surgical or medical procedure percutaneously on the patient using instruments and implants locatable relative to spinal elements in a known position in the surgical navigation system.
• In another aspect, the method includes inserting screws or rigid wires in spinal elements in the area involved in the anticipated surgical procedure before scanning the patient, and after scanning the patient and bringing the patient to the operating area, touching an image-guided or tracked surgical pointer to these screws and wires attached to the vertebrae to positively register their location in the surgical navigation computer, and manipulating either the patient's spine or the image to align the actual position of the spinal elements with the scanned image.
• In another aspect, the method includes percutaneously implanting screws into spinal elements, which screws are located using image guided surgical navigation techniques, and further manipulating the orientation of the screw heads percutaneously using a head-positioning probe containing an emitter, that can communicate to the surgical navigation computer the orientation of the screw heads and position them, by use of a specially designed head-positioning tool with an end portion that mates with the heads of the screws and can rotate those screw heads to receive a rod, wire, plate, or other connecting implant. If a rod is being inserted into the screw heads for example, the method further includes tracking the location and position of the rod, percutaneously using a rod inserter having one or more emitters communicating the location and orientation of the rod to the surgical navigation computer.
• According to various embodiments, a system and method is provided to a user, such as a surgeon, to track an instrument and surgical implants used in conjunction with a surgical navigation system in such a manner to operate percutaneously on a patient's body parts, such as spinal vertebrae which can move relative to each other.
• According to various embodiments, is provided a system and method to simply and yet positively indicate to the user a change in position of body parts, such as spinal vertebrae segments, from that identified in a stored image scan, such as from an MRI or CAT scan, and provide a method to realign those body parts to correspond with a previously stored image or the image to correspond with the actual current position of the body parts.
• According to various embodiments, is provided a system or method for allowing a fiducial array or reference arc that is removable from a location rigidly fixed to a body part and replaceable back in that precise location.
• According to various embodiments, is provided a system and method for positively generating a display of instruments and surgical implants, such as, for example screws and rods, placed percutaneously in a patient using image-guided surgical methods and techniques.
• According to various embodiments, is provided a percutaneous reference array and fiducial array, as described herein, to be used to register and track the position of the vertebrae for the purposes of targeting a radiation dose to a diseased portion of said vertebrae using a traditional radiosurgical technique.
• Additional application of the teachings will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the teaching. The applications of the teachings will be realized and attained by means of the elements and combinations particularly pointed out in this description.
• It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.
• Further areas of applicability of the present teachings will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and various examples, while indicating various embodiments, are intended for purposes of illustration only and are not intended to limit the scope of the teachings.
BRIEF DESCRIPTION OF THE DRAWINGS
• The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the teachings and together with the description, serve to explain the principles of the invention.
• FIG. 1 is a schematic diagram of various embodiments of a superstructure for use with the current teachings, including a reference arc, center post and fiducial array and rigid Kirschner wires (“K wires”) and screws placed in the spine for use with a surgical navigation system for percutaneous spinal surgical procedures.
• FIG. 1A is an enlarged view of the superstructure depicted inFIG. 1 engaging a vertebra by a clamp and also K wires implanted in adjacent vertebrae in the superior and inferior positions of the spinous process.
• FIG. 2 is a diagram of various embodiments of a clamp fixture for rigid connection to the spinous process of a single vertebrae with an H-shaped fiducial array attached to a center post rigidly attached to the clamp and a mating connector at the tip of the post for mating with a reference array, and a reference array for use in the current invention.
• FIG. 2A is a side view ofFIG. 2.
• FIG. 2B is another side view ofFIG. 2.
• FIG. 2C is a top view ofFIG. 2.
• FIG. 2D is an exploded view ofFIG. 2 without the reference arc.
• FIG. 2E is an exploded view of the interface of the center post and clamp ofFIG. 2.
• FIG. 3 is a diagram of a W-Shaped fiducial array mounted to a central post with generally spherical fiducials attached to the array, for mounting to a single vertebrae.
• FIG. 3A is a side view ofFIG. 3.
• FIG. 3B is another side view ofFIG. 3.
• FIG. 3C is a top view ofFIG. 3.
• FIG. 4 is a diagram of a reference arc and fiducial attached to a center post for use in the current invention in mounting to a single vertebrae.
• FIG. 4A is a side view ofFIG. 4.
• FIG. 4B is a back view ofFIG. 4.
• FIG. 4C is a top view ofFIG. 4.
• FIG. 4D is an expanded view ofFIG. 4.
• FIG. 4E is an expanded side view ofFIG. 4.
• FIG. 4F is an expanded view of the array foot and shoe ofFIG. 4E.
• FIG. 5 is a diagram according to various embodiments of a fixture using a cannulated screw for insertion into a vertebrae, with Kirschner wire mounted on a central post and including a fiduciary array and reference arc combined on a single structure.
• FIG. 6 is a side view of the screw and Kirschner wire fixture ofFIG. 5 implanted in a spinous process of a vertebrae.
• FIG. 7 is a diagram of a screw-head positioning probe and multiaxial screw for insertion into a single vertebrae.
• FIG. 7A is a diagram of the screw ofFIG. 7.
• FIG. 8 is a diagram of a head positioning probe, multiaxial screw and spinal segment.
• FIG. 9 is a diagram of a rod inserter with an LED.
• FIG. 10 is a diagram of various embodiments of the teachings including a cannulated tube and attachment for holding a reference arc.
• FIG. 11 is a diagram of the cannulated tube ofFIG. 10 with a reference arc and screw for attachment to a spinal process.
• FIG. 12 is a posterior view of spinal segment and implanted screws before alignment.
• FIG. 13 is a posterior view of spinal segment and implanted screws after alignment.
DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS
• Reference will now be made in detail to various embodiments, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The following example is intended to be purely exemplary.
• As generally described in PCT/US95/12894, the entire disclosure of which is incorporated herein by reference, a typical surgical navigation system is shown inFIG. 1. A computer assisted image-guided surgery system, indicated generally at10, generates an image for display on amonitor106 representing the position of one or more body elements, such as spinal elements fixedly held in a stabilizing frame or device such as aspinal surgery frame125 commonly used for spinal surgery. Areference arc120 bearing tracking means or emitters, such as forexample LED emitters122, is mounted to the spinous process by acentral post150. Thestructures20 and Kwires260 ofFIG. 1 are depicted in more detail inFIG. 1A. Theimage105 is generated from an image data set, usually generated preoperatively by a CAT scanner or by MRI for example, whichimage105 has reference points for at least one body element, such as a spinal element or vertebrae. The reference points of the particular body element have a fixed spatial relation to the particular body element.
• The system includes an apparatus such as a digitizer or other Position Sensing Unit (PSU), such as forexample sensor array110 onsupport112 for identifying, during the procedure, the relative position of each of the reference points to be displayed by tracking the position ofemitters122 onarc120. The system also includes aprocessor114 such as a PC or other suitable workstation processor associated withcontroller108 for modifying the image data set according to the identified relative position of each of the reference points during the procedure, as identified bydigitizer110. Theprocessor114 can then, for example, generate an image data set representing the position of the body elements during the procedure for display onmonitor106. Asurgical instrument130, such as a probe or drill or other tool, may be included in the system, which is positioned relative to a body part and similarly tracked bysensor array110.
• In summary, the general operation of a surgical navigating system is well known in the art and need not further be described here.
• With further reference toFIGS. 1 through 6, aregistration device20 is rigidly fixed to a spinal element by, for example, a device such as abone clamp30 depicted inFIG. 2. Alternatively, ascrew retention device40, such as the cannulatedscrew42 depicted inFIG. 5, and described in more detail below, can be used.
• With reference now toFIG. 2,bone clamp30 is fixedly attached to the spinous process. Theclamp30 includes at least two blades (or jaws)32 with tips orteeth34, which are preferably sharp, for driving together and penetrating soft tissue or more dense bone for rigid fixation to the spinous process. Theteeth34 are also preferably sized to accommodate the bulb shape of the spinous process. Thedriving mechanism40 is, for example, a screw driven into asleeve41 and is also preferably located such that it will be accessible in a percutaneous manner. Attached to theclamp30 is asuperstructure20. Thesuperstructure20 includes acentral post150 which is relocatable, that is, it fixes to theclamp30 in a rigid fashion, for example, as depicted inFIGS. 2D and 2E, by being inserted into a V-shapedwedge44 orienting thepost150 front to back and providing amating hole48 along thewedge44 for insertion ofpost150 in a single orientation and also providing fasteners such asscrew43 for tightening to lock thepost150 in place. Thepost150 can be removed and reapplied by loosening and tighteningscrew43, such that the original geometry and orientation is maintained. Thecentral post150 has at its apex aconnector60 with unique geometrical configuration, such as, for example, a starburst, onto which aspinal reference arc120 of thesuperstructure20 attaches. Any suchstandard reference arc120 can be used, such as depicted inFIGS. 1A, 4, and11, preferably includingemitters122, such as for example LEDs or reflective spheres for providing a positive indication of movement to the surgical navigation system during a procedure.
• Also rigidly attached to thecentral post150, as part of thesuperstructure20 preferably at a location closer to the skin, or possibly collocated with or also performing the function of thereference arc120, is afiducial array170, which can be of various different shapes, such as, for example the H-shapedframe170 depicted inFIG. 2, the W-shapedframe170′ as depicted inFIG. 3, theU-shaped frame170″ as depicted inFIG. 4 or theX-shaped frame120′,170′″ depicted inFIG. 5 (depicting a structure that is both a fiducial array and a reference arc). As depicted inFIGS. 2 and 3, this array can includefiducial points29 orspheres17, rigidly attached tofiducial array170,170′ and is, for example, as depicted inFIG. 3, substantially in the shape ofspheres17 and of a material detectable by the CAT scan or MRI, preferably titanium or aluminum. This fiducial array such as170 indicates to the surgical navigation system the location of the bone structure to which theclamp30 andcentral post150 are attached by touching a pointed surgical tracker tofiducial points29 or a cup-shaped probe tofiducial spheres17, thereby indicating the center of the fiducial to thesurgical navigation controller114. Thearray170 andcentral post150 are also attached to theclamp30, as described above, in such a way that they can be removed and replaced in the same geometric orientation and location, for example, by means of a uniquely shaped interface, for example, a triangle, or a single unique shape or a combination of unique angles or pins with theclamp30 such that thepost150 can only be reinserted the same way it was removed.
• Additionally, thefiducial array170, can be located at various heights on thepost150 to accommodate variations in patient tissue depth and size, preferably as close to the patient's body as possible, and then fixed at that specific height by the use of pins or indents matched to holes19 (shown inFIG. 2) in thecentral post150 or by placing therods39 of H-shapedarray170 indifferent holes31. Thefiducial array170 also has, for example, divots29 (shown inFIG. 2) shaped to interface with an instrument such as asurgical pointer130 which can touch thatdivot29 to register the location of thedivot29 and, thus, the location of thefiducial array170 and likewise the spinal element in the surgical navigation system. Multiple divots can be registered to further increase accuracy of the registration system. In one preferred embodiment of the array, thefiducials17 or29 can be mounted in a manner such that they can be adjusted, for example by mounting them on a rotatable or collapsible arm66 (as depicted inFIG. 3) that pivots and folds together, to get the maximum distance between fiducials while not dramatically increasing the field of view required at the time of scanning.
• Alternatively, rather than usingclamp30, ascrew42 andrigid wire45 attachment, as depicted inFIGS. 5 and 6, may be used to rigidly attach the central post of thesuperstructure20 to a body element, such as, for example, a vertebrae. As depicted inFIG. 6, screw42 is screwed into the spinal process ofspinal element100. Arigid wire45, post, or other sufficiently rigid fastener such as for example a Kirschner wire (K-wire), is inserted through the cannulation in the center ofpost150 and thescrew42 or is otherwise fixed to thescrew42, and exits the tip of thescrew42 at some angle, and is also implanted into thespinal element100 to prevent thescrew42 from rotating in either direction.
• Another embodiment for preventing thesuperstructure20 from rotating as depicted inFIGS. 10 and 11 includes the insertion of ascrew85 through a cannulatedtube86 which hasteeth89 in the end (or V-shaped end) that would bite into the tip of the spinous process, preventing rotation.
• Having described various embodiments of this apparatus of the present system, a method of using this apparatus for registering a single vertebrae will now be discussed. The operation of a surgical navigating system is generally well known and is described in PCT/US95/12894. According to various embodiments method of operation, clamp30 ofFIG. 2 or screw42 and K-Wire45 ofFIG. 5 are implanted percutaneously through a small incision in the skin and rigidly attached to the spinal process. This attachment occurs with theclamp30, by driving theblades32 of theclamp30 together to hold the spinous process rigidly. Thecentral post150 is then rigidly fixed to theclamp30 orscrew42 and thefiducial array170 is rigidly fixed to thecentral post150. The patient is then scanned and imaged with a CAT scan or MRI with a field of view sufficiently large to display the spinal anatomy and theclamp30 orscrew42 and thefiducial array170. This scan is loaded into the surgicalnavigation system processor104.
• After scanning the patient, thearray120 and post150 can be removed from the patient, while leaving in place the rigidly connectedclamp30 orscrew42. For example, as depicted inFIGS. 4D and 4E, afoot55 located belowarray170″ engages withshoe56 and rigidly connected byscrews57 and58. Before the surgical procedure, thepost150,array120 and other remaining portions of thesuperstructure20, once removed, may be sterilized. The patient is then moved to the operating room or similar facility from, for example, the scanning room.
• Once in the operating room, the patient may be positioned in an apparatus, such as, for example, aspinal surgery frame125 to help keep the spinal elements in a particular position and relatively motionless. Thesuperstructure20 is then replaced on theclamp30 orscrew42 in a precise manner to the same relative position to the spinal elements as it was in the earlier CAT scan or MRI imaging. Thereference arc120 is fixed to the starburst orother interface connector60 on thecentral post150 which is fixed to theclamp30 orscrew42. The operator, for example a surgeon, then touches an instrument with a tracking emitter such as asurgical pointer130 withemitters195 to thedivots29 on thefiducial array170 to register the location of thearray170 and, thus, because the spinal process is fixed to thefiducial array170, the location of the spinal element is also registered in the surgical navigation system.
• Once thesuperstructure20 is placed back on the patient, anyinstrument130 fitted with tracking emitters thereon such as, for example, a drill or screw driver, can be tracked in space relative to the spine in the surgical navigation system without further surgical exposure of the spine. The position of theinstrument130 is determined by the user stepping on afoot pedal116 to begin tracking theemitter array190. Theemitters195 generate infrared signals to be picked up bycamera digitizer array110 and triangulated to determine the position of theinstrument130. Additionally, other methods may be employed to track reference arcs, pointer probes, and other tracked instruments, such as with reflective spheres, or sound or magnetic emitters, instead of LED's. For example, reflective spheres can reflect infrared light that is emitted from thecamera array110 back to thecamera array110. The relative position of the body part, such as the spinal process is determined in a similar manner, through the use ofsimilar emitters122 mounted on thereference frame120 in mechanical communication with the spinal segment. As is well known in this art and described generally in PCT/US95/12894, based upon the relative position of the spinal segment and the instrument130 (such as by touching a known reference point) the computer would illustrate a preoperative scan—such as the proper CAT scan slice—on the screen ofmonitor106 which would indicate the position of thetool130 and the spinal segment for the area of the spine involved in the medical procedure.
• For better access by the operator of various areas near thecentral post150, thefiducial array170 can be removed from thecentral post150, by, for example, looseningscrew42 and sliding thearray170 offpost150, leaving thereference arc120 in place or replacing it after removal ofarray170. By leaving thereference arc120 in place, the registration of the location of the spinal process is maintained. Additionally, thecentral post150,reference arc120, andfiducial array170 can be removed after the spinal element has been registered leaving only theclamp30 orscrew42 in place. The entire surgical field can then be sterilized and asterile post150 andreference arc170 fixed to theclamp30 or screw42 with the registration maintained.
• This surgical navigation system, with spinal element registration maintained, can then be used, for example, to place necessary and desired screws, rods, hooks, plates, wires, and other surgical instruments and implants percutaneously, using image-guided technology. Once the location of thespinal element100 involved in the procedure is registered, by the process described above, in relation to the image data set andimage105 projected onmonitor106,other instruments130 and surgical implants can be placed under the patient's skin at locations indicated by theinstrument130 relative to thespinal element100.
• Additionally, the location of other spinal elements, relative to thespinal element100 containing thefiducial array170, can be registered in the surgical navigation system by, for example, insertingadditional screws250,rigid wires260, or other rigid implants or imageable devices into the spinal segment.
• For example, as depicted inFIG. 1, and in more detailFIG. 1A,additional screws250 or rigid and pointedwires260 are placed in the vertebrae adjacent to the vertebrae containing theclamp30 and post150 prior to scanning. On theimage105 provided bymonitor106, the surgeon can see theclamp30 orscrew42 andfiducial array170 and also theadditional screws250,wires260 or other imageable devices. When screws250 or other devices are used, these screws250 (as depicted inFIG. 7) may contain adivot256 or other specially shaped interface on thehead255 so that apointer probe130 can be used to point to thehead255 of the screw250 (or wire) and indicate the orientation of thescrew250 orwire260 to the surgical navigation system by communicating to thecontroller114 or by emission fromLEDs195 onprobe130 todigitizer110. The image of theseadditional screws250 also appear in the scan. Once the patient is then moved to the operating facility, rather than the scanning area, the image of thescrew250 can be compared to the actual position of thescrew250 as indicated by thepointer probe130 that is touched to thehead255 of thescrew250 orwire260. If necessary, the operator can manipulate the position of the patient to move the spinal element and thus the location of thescrew250 orwire260 to realign the spinal elements with the earlier image of the spine. Alternatively, the operator can manipulate the image to correspond to the current position of the spinal segments.
• For additional positioning information, the operator can place additionalrigid wires260 orscrews250 into the vertebrae, for example, located at the superior (toward the patient's head) and inferior (towards the patient's feet) ends of the spinal process to more accurately position those vertebrae relative to the other vertebrae and the image data. Additionally, thewires260 andscrews250 implanted to provide positioning information can also be equipped with emitters, such as, for example, LEDs, to provide additional information to the surgical navigation system on the location of thewire260 or screw250, and thus the vertebra to which they are affixed.
• Alternatively, the patient can be placed in a position stabilizing device, such as aspinal surgery frame125 or board, before a scan is taken, and then moved to the operating facility for the procedure, maintaining the spine segments in the same position from the time of scanning until the time of surgery. Alternatively, a fluoroscope can be used to reposition the spinal segments relative to the earlier image from the scan. An ultrasound probe can be used to take real-time images of the spinal segment which can be portrayed bymonitor106 overlayed or superimposed onimage105. Then the operator can manually manipulate the spinal elements and take additional images of these elements with the fluoroscope to, in an iterative fashion, align the spinal elements with the previously scannedimage105.
• Alternatively, aclamp30 orscrew42 andsuperstructure20 can be rigidly fixed to each vertebra involved in the surgical or medical procedure to register the position of each vertebra as explained previously for a single vertebra.
• After the spinal elements are registered in the spine, various medical and surgical procedures can be performed on that patient. For example, spinal implants, endoscopes, or biopsy probes can be passed into the spine and procedures such as, for example, spinal fusion, manipulation, or disc removal can be performed percutaneously and facilitated by the surgical navigation image-guiding system. Additionally, a radiation dose can be targeted to a specific region of the vertebrae.
• One such procedure facilitated by the apparatus and methods described above is the percutaneous insertion of screws and rods, fixed to different vertebra in a spine to stabilize them. Once screws, for examplemultiaxial screws250, (as depicted inFIG. 12, before manipulation) are implanted through small incisions they can be manipulated by a head-positioning probe280. The final position ofscrews250 and heads255 are depicted inFIG. 13. Thisprobe280, as depicted inFIG. 7, includes ahead285 that mates in a geometrically unique fashion with thehead255 of thescrew250. An emitter, such as, for example, anLED array380 on theprobe280, indicates the location and orientation of thescrew head255 to thecomputer114 of the surgical navigation system by providing an optical signal received bydigitizer110. Thescrew head255 can then be rotatably manipulated under the patient's skin by thehead positioning probe280 to be properly oriented for the receipt of arod360 inserted through therotating head255. The operator can then plan a path from thehead255 of eachscrew250 to theother screws250 to be connected. Then, with reference now toFIG. 9, an optically trackedrod inserter245 also equipped with emitters, such as, forexample LEDs247, can be placed through another small incision to mate with and guide arod360 through the holes or slots in the screw heads245, through and beneath various tissues of the patient, with therod inserter245, and, therefore, therod360, fixed to theinserter245, being tracked in the surgical navigation system. The operator can also use thecomputer114 to determine the required bending angles of therod360. For greater visualization, the geometry of thescrews250 could be loaded into thecomputer114 and when the position and orientation of thehead255 is given to thecomputer114 via theprobe280, thecomputer114 could place this geometry onto the image data and three-dimensional model. Therod360 geometry could also be loaded into thecomputer114 and could be visible and shown in real time onmonitor106 as the operator is placing it in the screw heads255.
• In an alternative procedure, one or more plates and/or one or more wires may be inserted instead of one ormore rods360.
• It will be apparent to those skilled in the art that various modifications and variations can be made in the present teachings and in construction of this surgical navigation system without departing from the scope or spirit of the teachings. Other embodiments of the teachings will be apparent to those skilled in the art from consideration of the specification and practice of the teachings disclosed herein. It is intended that the specification and examples be considered as exemplary only.

Claims (53)

1. A method of positioning an implant in an anatomy, including a first implant portion and a second implant portion with a surgical navigation system, comprising:

positioning the first implant portion through an opening in a soft tissue of the anatomy;

tracking a position of the first implant portion;

interconnecting an implant inserter with the second implant portion;

determining a location of the second implant portion; and

moving the second implant portion relative to the first implant portion via determining a location of the second implant portion.

2. The method ofclaim 1, wherein positioning a first implant portion through an opening in a soft tissue, moving the second implant portion relative to the first implant portion, or combinations thereof includes positioning the first implant portion, the second implant portion, or combinations thereof percutaneously.

3. The method ofclaim 2, wherein tracking a position of the first implant portion includes;

interconnecting a tracking apparatus with the first implant portion; and

tracking the tracking apparatus interconnected to the first implant portion.

4. The method ofclaim 3, further comprising:

determining a position of the portion of the first implant portion;

wherein moving the second implant portion relative to the first implant portion includes determining a location of a second implant portion relative to the first implant portion.

5. The method ofclaim 4, further comprising:

displaying the determined position of the first implant portion and the position of the second implant portion.

6. The method ofclaim 1, further comprising:

configuring the second implant portion based upon a tracked position of the first implant portion, a determined location of the second implant portion, or combinations thereof.

7. The method ofclaim 1, further comprising:

interconnecting a reference frame with the anatomy.

8. The method ofclaim 7, further comprising:

displaying a determined position of the second implant portion on a display relative to a registered image of the anatomy.

9. The method ofclaim 1, further comprising:

interconnecting a tracking apparatus with the implant inserter; and

tracking the tracking apparatus.

10. The method ofclaim 1, wherein determining a location of the second implant further includes tracking the tracking apparatus.

11. The method ofclaim 9, wherein the tracking apparatus includes a sensor.

12. The method ofclaim 11, further comprising:

selecting a sensor to include at least one of a light emitter, an infrared light emitter, an electromagnet, a magnet, a radiation emitter, or combinations thereof.

13. The method ofclaim 1, further comprising:

imaging the anatomy while at least one of tracking the position of the first implant, tracking the tracking apparatus, determining a location of a portion of the second implant portion, or combinations thereof.

14. The method ofclaim 13, wherein imaging the anatomy includes imaging the anatomy with an ultrasound system.

15. The method ofclaim 1, further comprising:

positioning a third implant portion through an opening in a soft tissue; and

interconnecting the first implant portion and the third implant portion with the second implant portion by moving the second implant portion relative to the first implant portion and the third implant portion.

16. The method ofclaim 1, wherein said first implant portion is a slot in a screw head;

wherein said second implant portion is a rod;

wherein moving the second implant portion includes aligning the rod with the slot.

17. The method ofclaim 16, further comprising:

fixing the first implant portion to a vertebrae.

18. The method ofclaim 1, wherein tracking a position includes tracking with an acoustic tracking system, optical tracking system, electromagnetic tracking system, micropulsed radar, or combinations thereof.

19. A method of performing a spinal procedure in an anatomy with a surgical navigation system, comprising:

positioning a first screw implant in a vertebrae percutaneously through an opening in a soft tissue of the anatomy;

tracking a position of the first screw implant;

orientating the first screw implant in a selected orientation at least in part via tracking the position of the first screw implant;

interconnecting an implant inserter with a rod;

determining a position of a portion of the rod; and

moving the rod relative to the first screw implant via determining a location of the rod to interconnect the screw with rod.

20. The method ofclaim 19, further comprising:

interconnecting a second tracking apparatus with the implant inserter.

21. The method ofclaim 19, wherein orientating said first screw implant includes orientating a slot defined by the screw.

22. The method ofclaim 21, wherein tracking a position of the first screw implant includes interconnecting a screw tracking apparatus with the first screw implant.

23. The method ofclaim 22, wherein interconnecting the screw tracking apparatus includes selecting a sensor.

24. The method ofclaim 23, wherein selecting the sensor includes selecting a light emitting diode, a light reflector, an infrared emitter, a magnet, an electromagnet, an acoustic emitter, an infrared reflector, or combinations thereof.

25. The method ofclaim 22, wherein interconnecting the screw tracking apparatus with the first screw implant includes positioning the screw tracking apparatus percutaneously.

26. The method ofclaim 22, wherein tracking the tracking apparatus includes at least triangulating a position of the tracking apparatus with the surgical navigational system.

27. The method ofclaim 26, wherein the surgical navigation system includes an acoustic tracking system, or electromagnetic tracking system, an optical tracking system, a micropulsed radar, or combinations thereof.

28. The method ofclaim 19, wherein orientating the first screw implant includes selecting an orientation of a head of the screw relative to a portion of the anatomy.

29. The method ofclaim 21, wherein orientating the first screw implant includes orientating the slot relative to the anatomy.

30. The method ofclaim 29, further comprising:

positioning a second screw implant in a vertebrae percutaneously; and

orientating the second screw implant;

wherein orientating the second screw implant includes orientating second screw implant relative to the first screw implant.

31. The method ofclaim 30, wherein moving the rod relative to the first screw implant includes moving the rod relative to both the first screw implant and the second screw implant.

32. The method ofclaim 31, further comprising:

manipulating the rod to achieve an interconnection of the first screw implant and the second screw implant.

33. The method ofclaim 19, wherein interconnecting the implant inserter with the rod includes interconnecting the implant inserter near a first end of the rod, a second end of the rod, a portion intermediate between the first end and the second end, or combinations thereof.

34. The method ofclaim 19, wherein interconnecting an implant inserter with a rod includes rigidly interconnecting an implant inserter with the rod.

35. The method ofclaim 34, further comprising:

interconnecting a tracking apparatus with the implant inserter that includes rigidly interconnecting the tracking apparatus with the implant inserter.

36. The method ofclaim 19, wherein interconnecting an implant inserter with a rod includes releasably interconnecting the implant inserter with the rod.

37. The method ofclaim 19, further comprising:

interconnecting a tracking apparatus with the implant inserter that includes positioning an emitter on the tracking apparatus.

38. The method ofclaim 37, wherein interconnecting a sensor with the tracking apparatus includes selecting at least one of a light emitting a diode, a light reflecting portion, an infrared light emitting portion, an infrared light reflecting portion, an acoustic emitter, an electromagnet, a magnet, or combinations thereof.

39. The method ofclaim 19, further comprising:

imaging a portion of the anatomy.

40. The method ofclaim 39, wherein imaging a portion of the anatomy includes obtaining an MRI scan, a CT scan, an x-ray image, an ultrasound image, or combinations thereof.

41. The method ofclaim 19, further comprising:

displaying an image of the anatomy; and

displaying a position of the portion of the screw on the display relative to the image of the anatomy, and displaying a determined position of the rod relative to the image of the anatomy.

42. The method ofclaim 41, wherein moving the rod relative to the screw includes displaying on the display the portion of the rod relative to the position of the head of the screw.

43. The method ofclaim 42, further comprising:

manipulating the rod to achieve a selected interconnection of the rod and the screw implant.

44. The method ofclaim 43, wherein manipulating the rod includes bending the rod.

45. The method ofclaim 44, further comprising:

positioning a second screw implant in a vertebrae percutaneously; and

moving the rod relative to the screw implant and the second screw implant.

46. The method ofclaim 19, wherein moving the rod relative to the screw includes moving the rod substantially percutaneously.

47. The method ofclaim 46, wherein moving the rod substantially percutaneously includes inserting the rod through a substantially single opening in a soft tissue of the anatomy and moving the rod based upon a tracked position of the rod.

48. The method ofclaim 47, wherein tracking a position of the portion of the screw and determining a position of a portion of the rod is substantially percutaneous.

49. The method ofclaim 19, wherein tracking the position of the first screw implant includes tracking a position of a slot defined by the screw.

50. The method ofclaim 49, wherein moving the rod relative to the first screw implant includes moving the rod percutaneously through the slot.

51. The method ofclaim 50, further comprising:

positioning a second screw implant in a vertebrae percutaneously through an opening in a soft tissue of the anatomy;

tracking a position of the second screw implant; and

orientating the second screw implant in a selected orientation at least in part via tracking the position of the second screw implant.

52. The method ofclaim 51, wherein orientating the second screw implant includes aligning a second slot defined by the second screw implant with a first slot defined by the first screw implant at least in part by tracking the position of the first screw implant, tracking the position of the first screw implant, or combinations thereof;

wherein moving the rod includes moving the rod through the first slot and the second slot;

53. The method ofclaim 52, further comprising:

fixing the rod to the first screw implant and the second screw implant.

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