Patent Publication Number: US-2016228033-A1

Title: Reference device for surgical navigation system

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention relates generally to surgical navigation systems. More particularly, the present invention relates to a referencing device for a surgical navigation system, a marker carrier unit for use in a referencing device as well as a method for surgical navigation. 
     2. Related Art 
     Surgical navigation systems are employed in a variety of surgical applications, for example, in neurosurgery, oral, maxillofacial and facial surgery, ear nose and throat (ENT) surgery or also for limb implantation in orthopedic surgery. Based on three-dimensional patient image data, which are obtained by means of X-ray images, computer tomography (CT), magnetic resonance tomography (MRT) and/or positron emission tomography (PET), surgical navigation systems of this type enable the position of medical instruments to be visualized in real-time in the patient image data in order to thereby assist the surgeon during operable procedures. 
     To this end, it may be necessary to record and monitor the position and orientation of the patient or a specific body part on which a surgical procedure is to be carried out—also referred to as “tracking.” Conventional referencing devices have been used usually comprising reference frames to which marking elements such as light-reflecting, spherical marker elements are attached. The light-reflecting spherical marker elements allow a stereo camera system of the navigation system to record the precise position and orientation of the referencing device. 
     Conventional navigation systems and/or referencing devices are known, for example, from documents DE 10 2011 054 730 A1, DE 698 33 881 T2, DE 10 2010 060 914 A1 or DE 60 2004 004 158 T2. WO 2006/012491 discloses marker elements together with a unit carrying the marker elements—referred to as reference frames—as a single disposable unit which can be produced by injection molding. However, traditional navigation systems do not always allow for the desired positioning and orientation of the referencing device, for example, due to structural limitations in the design of its arranged configuration and/or restrictions in movement such as limited multiple ranges of motion and/or operating degrees of freedom. 
     Another concern may include operating and maintaining a sterile environment during surgical procedures. Medical devices, such as referencing devices must also be sterile. Within such an environment, marker elements may be removably attached, for example, by means of a standardized clip attachment to pins arranged on the referencing device. The referencing device may thus be sterilized without marker elements and new, sterile, disposable marker elements may be utilized for each use. Conventional corresponding marker elements are known, for example, from document DE 10 2009 019 986 A1. 
     In order to deduce the position and orientation of a patient (or as the case may be, the body part of a patient on which a surgical procedure is to take place), and in order to produce a correct reference to the 3D image data, it is necessary to calibrate the surgical navigation system by executing a registration step. Various reference points are thereby successively localized on the patient using a navigation apparatus and correlated with corresponding points in the 3D image data. 
     The registration process determines the geometric relationship between the anatomic structures of interest and the 3-dimensional (3D) computer image constructed, for example, from the preoperative CT scan. Registration involves two steps. First, the reference sensor is secured to a non-mobile structure. Then, a registration tip, for example, is used sequentially to touch pre-selected registration points (e.g., fiducial markers). Registration points may be any anatomic structures that are recognizable on the preoperative image (e.g. teeth, skin, bone). Each time a registration point is touched with the registration tip, the computer records the location of the position sensor and the reference sensor. Using, for example, at least three registration points, the computer calculates the physical position of the anatomic structure with respect to the reference sensors. The computer then uses this registration information to measure the position of the pencil relative to the preoperative CT scan. The patient&#39;s body part can be mobilized freely without the need to re-initialize the registration process, because the reference sensor is rigidly attached to the relevant structure of the patient. By way of this registration, a correct, spatial reference between the 3D image data and the position and orientation of the body part of the patient can be produced. 
     In particular, in the case of surgical procedures involving the brain, it is usually not possible to simply be limited to reference points in the operating area for a necessarily precise registration, but rather it is necessary, in the vast majority of cases, to select a plurality of reference points at different locations on the body of the patient. Since for this purpose unhindered access to these locations on the body of the patient is necessary, registration must thus take place before the patient can be finally prepared for the actual surgical procedure and covered in a sterile manner in the areas outside of the operating area. 
     As a practical matter, and as it pertains to the registration device itself, following a successful registration procedure necessarily means he registration device must be considered as being potentially contaminated. Thus, appropriate measures for protecting the patient must be taken before the image-guided surgical procedure using the navigation system can take place. As such, the reference frame is thus usually detached from the fixation unit, sterilized, and provided with new sterile marker elements and reconnected to the fixation unit. The fixation unit as well as the interface between the fixation unit and the reference frame must next be draped and/or otherwise covered. To achieve this, holes are typically generated in medical drapes in order to allow the reference frame or its components to protrude therethrough and to subsequently attach to the fixation unit. Additional care to secure and maintain medical drapes is also provided in order to achieve a covering considered at least sufficiently secure. From a user perspective, this approach is presented as less than desirable since, on the one hand, the effort is labor intensive and significant staff effort is required in order to provide the necessary draping and covering for operational procedure. And, on the other hand, the draping and covering is often regarding as insufficiently secure for operating procedures. This risks the sterility of the operating environment and loss of time in addressing the same. 
     It is, therefore, an object of the present invention to overcome the deficiencies of the prior art to provide an improved apparatus capable of providing increased range of motion in at least multiple to an infinite amount of directions while more easily achieving and maintaining a sterile operating environment. It is a further goal of the present invention to provide a method and apparatus that achieves and maintains a dependable fixed position of the referencing device during operational procedures that eliminates the need to recalibrate the system. 
     SUMMARY 
     The foregoing needs are met, to a great extent, by the present invention, wherein in one aspect a device is provided that in some embodiments comprises a connection unit, a marker carrier unit removably attached to the connection unit and an attachment unit connected to the connection unit for fixing the device to a body part of a patient. The connection unit comprises an articulated arm wherein the marker carrier unit comprises an attachment area for removably attaching the marker carrier element to the connection unit. 
     In accordance with another embodiment of the present invention, a method is provided that in some embodiments comprises removably attaching a marker carrier unit to a connection unit of a referencing device by connecting an end of the connection unit to an attachment area of the marker carrier unit. The method may also include fixing another end of the connection unit to a body part of a patient, registering a correct spatial reference between a 3D image data and a position and orientation of a body part of the patient and removing the marker carrier unit from the connection unit at a location of the attachment area. Embodiments of the disclosed method may also include draping the connection unit with a medical drape and removably attaching a sterile marker carrier unit to the connection unit by connecting an end of the connection unit to an attachment area of the sterile marker carrier unit such that the medical drape is disposed within the attachment area of the sterile marker carrier unit and secured between the sterile marker carrier unit and the connection unit. 
     In accordance with yet another embodiment of the present invention, a method is provided that in some embodiments comprises removably attaching a marker carrier unit to an attachment mechanism of a connection unit by inserting the attachment mechanism into an attachment area of the marker carrier unit, fixing another end of the connection unit to a body part of a patient and registering a correct spatial reference between a 3D image data and a position and orientation of a body part of the patient. The method may also include removing the marker carrier unit from the connection unit by detaching the attachment mechanism from the attachment area. 
     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description of the invention herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as in the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the concept upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     Still other aspects, features and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating a number of exemplary embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention also is capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features of the invention. 
         FIG. 1  is a perspective view of a referencing device for a surgical navigation system according to an embodiment of the present invention. 
         FIG. 2  is an exploded view of an exemplary ball and socket joint disposed near one end of an articulated arm of the referencing device according to one embodiment of the present invention. 
         FIG. 3  is an exploded view of an exemplary rotary joint disposed along an articulated arm of the referencing device according to one embodiment of the present invention. 
         FIG. 4  is side view depicting the assembly of an attachment foot in connection with an articulated arm being mated with a marker carrier unit according to one embodiment of the present invention. 
         FIG. 5  is an exploded view of another exemplary ball and socket joint disposed near another end of an articulated arm of the referencing device according to one embodiment of the present invention. 
         FIG. 6  is a top view of an exemplary design of an attachment foot mated in an exemplary recess of a marker carrier body according to one embodiment of the present invention. 
         FIG. 7  is a cross sectional view taken along C-C of  FIG. 6  according to one embodiment of the present invention. 
         FIG. 8  is a top view of an exemplary design of an attachment foot mated in an exemplary recess of a marker carrier body according to one embodiment of the present invention. 
         FIG. 9  is a cross sectional view taken along D-D of  FIG. 8  according to one embodiment of the present invention. 
         FIG. 10  is another side view of an assembly of an exemplary attachment foot being secured to an exemplary marker carrier body via an exemplary design of a clamp lever according to one embodiment of the present invention. 
         FIG. 11  is another side view of an assembly of an exemplary attachment foot being secured to an exemplary marker carrier body via an exemplary design of a clamp lever according to one embodiment of the present invention. 
         FIG. 12  is a partial view of an exemplary attachment foot attached to an articulated arm via a ball and socket joint according to an embodiment of the present invention. 
         FIG. 13  illustrates an embodiment of a marker carrier unit for assembly with the illustrated exemplary attachment foot according to an embodiment of the present invention. 
         FIG. 14  illustrates steps for preparing and affixing the disclosed referencing device onto a patient for a surgical navigation procedure according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Definitions 
     Where the definition of terms departs from the commonly used meaning of the term, applicant intends to utilize the definitions provided below, unless specifically indicated. 
     For the purposes of the present invention, directional terms such as “top”, “bottom”, “upper”, “lower”, “above”, “below”, “left”, “right”, “horizontal”, “vertical”, “upward”, “downward”, etc., are merely used for convenience in describing the various embodiments of the present invention. 
     For purposes of the present invention, the term “ball and socket joint” (also referred to a ball joint) refers to a joint, as in a mechanical device, that permits rotary movement in all directions through the movement of a ball in a socket. The ball and socket joint is a joint in which the ball-shaped surface of one rounded member fits into a cup-like depression of another member. The distal member is capable of motion around an indefinite number of axes, which have one common center. It enables the member to move in many planes (almost all directions). 
     For purposes of the present invention, the term “distal” refers being situated away from a point of attachment or origin or a central point. 
     For purposes of the present invention, the term “drape” refers to the sterilized cloths that mark off an operative field. Typically the aforementioned cloths are arranged over a patient&#39;s body during an examination or treatment or during surgery and are designed to provide a sterile field around the area. “Draping” refers to the process thereof. 
     For purposes of the present invention, the term “Image-guided surgery” (IGS) refers to surgical procedures where the surgeon employs tracked surgical instruments in conjunction with preoperative or intraoperative images in order to indirectly guide the procedure. Image-guided surgery is part of the wider field of computer-assisted surgery. During a surgical procedure, the IGS tracks the probe position and displays the anatomy beneath it as, for example, three orthogonal image slices on a workstation-based 3D imaging system. Existing IGS systems use different tracking techniques including mechanical, optical, ultrasonic, and electromagnetic. 
     For purposes of the present invention, the term “indicia” refers distinctive marks, characteristic markers or indications. 
     For purposes of the present invention, the term “proximal” refers to being next to or nearest the point of attachment or origin, a central point, or the point of view; especially located toward the center of the body—compare distal. For purposes of the present invention, the term “distal” refers to the direction opposite the “proximal” direction. 
     For purposes of the present invention, the term “registering” refers to a process for determining the geometric relationship between an anatomic structure(s) of interest and a 3-dimensional (3D) computer image constructed, for example, from the preoperative CT scan. By way of this registration, a correct, spatial reference between the 3D image data and the position and orientation of the body part of the patient, observed by means of referencing device, can be produced. 
     For purposes of the present invention, the term “rotary joint” refers to a freely moving joint in which movement is limited to rotation; the rotary joint may be considered as a flexible joint that connects a stationary object with a rotating object in a piece of machinery, for example, factory and medical equipment. 
     For purposes of the present invention, the term “surgical navigation” refers to computer assisted surgery (CAS) representing a surgical concept and set of methods that use computer technology for pre-surgical planning and for guiding or performing surgical interventions. CAS is also known as computer aided surgery, computer assisted intervention, image guided surgery and surgical navigation. 
     For purposes of the present invention, the term “surgical navigation system” refers a system that allows visualization of an operative site and surgical instruments simultaneously and relates them to the patient&#39;s diagnostic images (e.g., computed tomographic (CT) scans and magnetic resonance imaging (MRI)). A surgical navigation system is used to guide the surgeon&#39;s movements during an operation. It may display the real-time position of each instrument and anatomical structure. These systems are used in orthopedics, ENT, neurology and other surgical specialties. Real-time observations occur via MRI, scanner, video camera or another imaging process. Navigation data are incorporated into the image to help the surgeon determine precise position within the organism. Medical imaging is sometimes used to plan an operation before surgery. Data integration enables the system to compare the actual position of the target object with the ideal location established during the planning phase. Such systems may be mechanical, electromagnetic or optical. The most common are optical devices, either passive or active. In the former, cameras locate specific markers such as reflective targets, particular shapes or colors. Active systems locate LEDs. 
     For purposes of the present invention, the term “x-direction” refers to the direction aligned with the x-axis of a coordinate system. 
     For purposes of the present invention, the term “y-direction” refers to the direction aligned with the y-axis of a coordinate system. 
     For purposes of the present invention, the term “z-direction” refers to the direction aligned with the z-axis of a coordinate system. 
     Description 
     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. The following detailed description is of example embodiments of the presently claimed invention with references to the accompanying drawings. Such description is intended to be illustrative and not limiting with respect to the scope of the present invention. Such embodiments are described in sufficient detail to enable one of ordinary skill in the art to practice the subject invention, and it will be understood that other embodiments may be practiced with some variations without departing from the spirit or scope of the subject invention. 
     Turning to  FIG. 1 , a referencing device  100  is illustrated for positioning and mounting one or more marker elements  110  disposed on a marker carrier body  112  of a marker carrier unit  116 . In the disclosed embodiment, marker carrier body  112  is substantially designed in as a three-armed unit wherein in the region of the end of each arm a marker element  110  is respectively arranged. Marker elements  110  may be designed as spherical marker elements including retro-reflective marker spheres, also referred to as passive reflective markers, and are widely used in image guidance systems. Embodiments of retro-reflective marker spheres may include those used to aid registration and instrument tracking during image guided surgery procedures such as neurological procedures, spine procedures and orthopedic procedures. Embodiments may include retro-reflective marker spheres having a high coefficient of retro-reflection on the external surface to provide feedback to the system/camera. Such surfaces may consist of micro glass spheres that reflect light. Depending on the medical application, different numbers and arrangements of retro-reflective marker spheres may be mounted on various types of surgical tools that may be used including that disclosed herein. Once mounted on a surgical probe, retro-reflective marker spheres provide an accuracy reference point for the surgical probe in three-dimensional space. 
     Disclosed embodiments provide the attachment of maker carrier unit  116  to a connection unit  126 , for example, at a prescribed location  114  of marker carrier body  112 . Prescribed location  114  may be located anywhere at the marker carrier unit  116 . In one exemplary configuration, connection unit  126  includes an articulated arm  128  comprising a plurality of arm extensions  118 ,  122  and joints  408  ( FIGS. 4 ),  120  and  124 . While two arm extensions  118 ,  122  and three joints  408 ,  120  and  124  are described and illustrated in the exemplary drawings, it is readily appreciated that more arm extensions and joints may be employed by the disclosed invention, for example, to facility increased mobility and degrees of freedom in motion of articulated arm  128  and, hence, referencing device  100 . Connection unit  126  may also comprise an attachment unit  132  and attachment foot  406  ( FIG. 4 ), as described below. 
     Arm extension  118  connects to marker carrier body  112  of marker carrier unit  116  at a first end and is configured to join with joint  120  at a second end. Arm extension  118  is a rigid arm extension and may be composed of stainless steel, medical grade steel, materials. In the disclosed embodiment, joint  120  may include a rotary joint for rotating arm extension  118  in the x-direction and y-direction direction (e.g., see  FIG. 3 ). Turning to  FIGS. 12 and 13 , the exemplary configuration of joint  120  may include to segment portions, i.e., lower portion  1204  and upper portion  1206  forming a rotary joint. Lower portion  1204  moves relative to upper portion  1206  in a rotary fashion. Likewise, upper portion  1206  moves relative to lower portion  1204  in a rotary fashion. In the disclosed embodiment, arm extension  118  is rigidly connected to lower portion  1204  and arm extension  122  is rigidly connected to upper portion  1206  of joint  120 . Thus each extension,  118 ,  122  moves relative to one another in rotary fashion. 
     Joint  120  may include a locking mechanism  136  for locking articulated arm  128  in a fixed position. For example, locking mechanism  136  may include a handle and a bolt (not shown) centering through joint  120  and in threaded engagement with the handle. Rotating the handle, for example, in a rotational direction, thereby, clamps down on joint  120  as the bolt is threaded into the handle thereby providing enough force to retain the joint and prevent further movement of the same. In the embodiment disclosed, for example, in  FIGS. 12 and 13 , upon tightening of the aforementioned handle, lower portion  1204  and upper portion  1206  would remain unmovable relative to one another and effectively “lock-down” joint  120  into a fixed or set configuration. Locking mechanism  136  may be configured to lock articulated arm  128 , including joints  124 ,  408 , such that articulated arm  128  becomes a completely rigid at a prescribed positioning. 
     Arm extension  122  connects with joint  120  at a first end and is configured to connect with joint  124  at a second end. Thus, joint  120  forms a joint connection between arm extension  118  and arm extension  122 . Joint  124  may include a ball joint wherein arm extension  122  connects with the ball portion of the pivot joint  134 . The ball joint permits rotary movement of arm extension  122  in the x-direction, the y-direction, and z-direction (e.g., see  FIG. 2 ). Arm extension  122  is a rigid arm extension that may be comprised of stainless steel, medical grade steel, materials. 
     An attachment unit  132  serves as a fixation device to connect to an extremity or body portion of a patient. Attachment unit  132  may also be configured to attach to other items used in surgery including, but not limited to, a human body part, a bone screw, or an implant. In the disclosed embodiment shown in  FIG. 1 , attachment unit  132  is configured as a head clamp designed to couple and attach with the head of a patient. However, it will be readily appreciated by those skilled in the art that attachment unit  132  may be designed to affix to other extremities or portions of a human patient including, for example, arms, legs, knees, angles, neck, wrists, hands, etc. Thus attachment unit  132  may comprise other alternative attachment mechanisms, for example, including attachment configurations for bone screws, spinal clamps, surgical pins, etc., or any other surgical mount suitable for affixing connection unit  126  to a human body part or extremity. The current embodiment depicts a mounting post  130  extending from attachment unit  132  and is configured to connectively attach to joint  124  thereby forming a joint connection between arm extension  122  and attachment unit  132 . Thus, joint  124  permits movement of articulated arm  128  and marker carrier unit relative to attachment unit  132  which may be affixed at a prescribed location, for example, on the body of a patient. While a select number of joints have been illustrated in the drawings and described in the specification, more or less joints may be utilized to form the articulated arm of connection unit  126 . In addition, other types of features may be utilized in the articulated arm including, for example, a telescopic feature employed in the arm extension for extending or shortening the arm extension along a length of connection unit  126 . 
     As previously mentioned above, arm extension  118  connects to marker carrier body  112  of marker carrier unit  116  at one end and is configured to join with joint  120  at another end. To connect with marker carrier unit  116 , arm extension  118  connects with joint  408  thereby forming a joint connection therebetween. Turning to  FIG. 4 , joint  408  may comprise a ball joint wherein arm extension  118  connects with the ball portion of the pivot joint  412 . Thus, the ball joint permits rotary movement of arm extension  118  in the x-direction, the y-direction, and z-direction (e.g., see  FIG. 5 ).  FIGS. 12 and 13  illustrate an embodiment of joint  408  represented as a ball and socket joint in which the ball-shaped surface of one rounded member  1200  fits into a cup-like depression of another member  1202 . Coupled to joint  408  is an attachment mechanism for coupling arm extension  118  to marker carrier body  112  via joint  408 . In the disclosed embodiment, the attachment mechanism comprises an attachment foot  406 . Joint  408  permits attachment foot  406  to have a range of motion around an indefinite number of axes having a common center. The disclosed configuration enables attachment foot  406  to move in many planes (almost all directions) as further described below. Earlier described joint  124  may also include the ball joint configuration represented by joint  408  and illustrated, for example, in the exemplary embodiments of  FIGS. 12 and 13 . 
     Arm extension  118  is a rigid arm extension that may be comprised of stainless steel, medical grade steel, materials. As illustrated in  FIG. 4 , marker element  110  is mounted on mounting post  414  rigidly fixed to marker carrier body  112 . Marker carrier body  112  comprises an attachment area  404  for receiving and coupling/mating an attachment mechanism, such as attachment foot  406 , in receiving area  402 . Receiving area  402  may be formed as a recess or cavity appropriately dimensioned and configured to receive and retain attachment foot  406  therein, as described below. Attachment foot  406  extends from joint  408  via mounting post  410 . Marker carrier unit  116  is ultimately retained on connection unit  126  via the receipt and retention of attachment foot  406 . Thus, by function of joint  124 , connection unit  126  is permitted to rotate and pivot relative to attachment unit  132 . By function of joint  408 , marker carrier unit  116  is permitted to rotate and pivot relative to connection unit  126 . 
       FIG. 6  illustrates a top view of one embodiment of attachment foot  406  mated in receiving area  402  of marker carrier body  112 . When received within receiving area  402 , select inner wall portions of marker carrier body  112  are sufficiently designed to contact points of the outer surface of attachment foot  406  to facilitate locating and securing the same therein. For example, in one disclosed embodiment locating contact surfaces  602  are formed to protrude into receiving area  402 . Locating contact surfaces  602  act as an alignment mechanism of marker carrier body  112  for positioning onto attachment foot  406 , as described below. Appropriately sized receiving areas  612  of attachment foot  406  are configured to receive corresponding locating contact surfaces  602  to form a mated configuration wherein the outer surface  614  of locating contact surfaces  602  generally abuts against the outer surface  616  of corresponding receiving areas  612 . Side edge surface  618  of attachment foot  406  also generally abuts corresponding side edges  620  of receiving area  402 . 
     A clamp lever  604  is provided to position and retain attachment foot  406  within receiving area  402 . Pin  606  is disposed through clamp lever  604  such that clamp lever  604  pivots about pin  606 . (As shown more easily in  FIG. 7 , pin  606  may be secured within the structure of marker carrier body  112 .) When clamp lever  604  is pivoted about pin  606 , the outer surface  610  of clamp lever  604  is rotated into contact with outer surface  608  of attachment foot  406  thereby providing a frictional interference fit in a clamped position. A material of attachment foot  406  and/or clamp lever  604  may be designed to withstand a certain amount of deflection to facilitate the frictional fit and retention of clamp lever  604  in the clamped position and thereby secure attachment foot  406  within receiving area  402 . 
       FIG. 7  provides a cross sectional view taken along C-C of  FIG. 6 . In the exemplary embodiment, a medical drape  700  may be disposed over attachment foot  406  within receiving area  402 . As illustrated in the current embodiment, the side circumference  710  of attachment foot  406  may be designed with a generally multi-angular configuration. Thus a top half  712  of the side circumference  710  may angle generally downwardly and away from a top surface  716  of attachment foot  406  to form a top half angled surface  406   b . A bottom half  714  of the side circumference  710  may angle generally upwardly and away from a bottom surface  718  of attachment foot  406  to form a bottom half angled surface  406   a . Top half angled surface  406   b  and bottom half angled surface  406   a  are configured to diverge into a point  702 . 
     Outer surface  614  of protruding locating contact surfaces  602  is designed to mate in complimentary fashion with the design configuration of top half angled surface  406   b  and the bottom half angled surface  406   a . Angled surfaces of outer surface  614  include a top half angled surface  602   b  and a bottom half angled surface  602   a  that diverge into point  704 . Accordingly, top half angled surface  602   b , bottom half angled surface  602   a  and point  704  of outside surface of contact surface  602  are formed in a complimentary configuration to mate with the angular design of corresponding top half angled surface  406   b , bottom half angled surface  406   a  and point  702 , respectively. 
     Next, the current embodiment of the configuration of outer surface  608  of attachment foot  406  with respect to outer surface  610  of clamp level  604  is described. The side circumference  710  of attachment foot  406  may be designed with a generally multi-angular configuration. Top half  712  of side circumference  710  may angle generally downwardly and away from top surface  716  of attachment foot  406  to form a top half angled surface  406   c . Bottom half  714  of side circumference  710  may angle generally upwardly and away from a bottom surface  718  of attachment foot  406  to form a bottom half angled surface  406   d . Top half angled surface  406   c  and bottom half angled surface  406   d  are configured to diverge at a point  706 . 
     Outer surface  610  of clamp lever  604  is designed to mate in complimentary fashion with the design configuration of top half angled surface  406   c  and bottom half angled surface  406   d . Angled surfaces of outer surface  610  include a top half angled surface  604   b  and a bottom half angled surface  604   a  that diverge at point  708 . Accordingly, top half angled surface  604   b , bottom half angled surface  604   a  of contact surface  610  and point  708  are formed in a complimentary configuration to mate with the angular design of corresponding top half angled surface  406   c , bottom half angled surface  406   d  and point  706 , respectively. 
     In operation, when clamp lever  604  is pivoted about pin  606  to bring outer surface  610  into contact with outer surface  608  of attachment foot  406 , top half angled surface  406   b , bottom half angled surface  406   a  and point  702  of attachment foot  406  mate with top half angled surface  602   b , bottom half angled surface  602   a  and point  704  of outside surface  614  of locating contact surface  602 , respectively. In this manner, locating contact surface  602  provides an alignment mechanism of marker carrier body  112  of the disclosed invention. This ensures that any marker carrier body  112  employing the designed receiving area  402  and the locating contact surfaces  602  will always be in the same position, location and/or orientation when mounted on the disclosed attachment foot  406  having corresponding complimentary receiving areas  612  after articulated arm  128  is set into a final position. Likewise, top half angled surface  604   b , bottom half angled surface  604   a  and point  708  of contact surface  610  mate with the angular design of corresponding top half angled surface  406   c , bottom half angled surface  406   d  and point  706  of attachment foot  406 , respectively. 
     Turning to  FIG. 8 , another embodiment of attachment foot  406  mated in receiving area  402  of an exemplary marker carrier body  112  is shown. Attachment foot  406  is mated in receiving area  402  of marker carrier body  112 . When received within receiving area  402 , select inner wall portions of marker carrier body  112  are sufficiently designed to contact points of the outer surface of attachment foot  406  to facilitate locating and securing the same therein. For example, general angular side contact surfaces  802  are formed at a complimentary angle to side angular contact surfaces  810  of attachment foot  406 . Angular side contact surfaces  802  are connected via a forward front surface  804 . Forward front surface  804  corresponds to a complimentary forward surface  806  of attachment foot  406 . Angular side contact surfaces  802  and forward front surface  804  act as an alignment mechanism of marker carrier unit  112 . Thus, when clamp lever  604  is rotated about pin  606 , outer surface  610  of clamp lever  604  is urged against rearward surface  812  of attachment foot  406 . This motion urges forward surface  806  of attachment foot  406  into contact with forward front surface  804 . Additionally, side angular contact surfaces  810  of attachment foot  406  abut angular side contact surfaces  802  of marker carrier body  112 . 
     In the cross sectional view of  FIG. 9  a medical drape  700  is disposed over attachment foot  406  within receiving area  402 . As illustrated in the current embodiment, the side circumference  908  of attachment foot  406  may be designed with a generally angular configuration. Thus, at a location disposed near forward surface  806 , a top half  912  of side circumference  908  may angle generally downwardly and inwardly from a top surface  914  of attachment foot  406  to form a top half angled surface  902   b  near forward surface  806 . A bottom half  916  of the side circumference  908  may angle generally upwardly and inwardly from a bottom surface  918  of attachment foot  406  to form a bottom half angled surface  902   a  near forward surface  806 . Top half angled surface  902   b  and bottom half angled surface  902   a  near forward surface  806  are configured to diverge into a point  910 . 
     Forward front surface  804  acts as an abutment surface and is designed to mate in complimentary fashion with the configuration of top half angled surface  902   b  and bottom half angled surface  902   a  of attachment foot  406 . Angled surfaces of forward front surface  804  include a top half angled surface  802   b  and a bottom half angled surface  802   a  that diverge into point  904 . Accordingly, top half angled surface  802   b , bottom half angled surface  802   a  and point  904  of forward front surface  804  are formed in a complimentary configuration to mate with the angular design of corresponding top half angled surface  902   b , bottom half angled surface  902   a  and point  910 , respectively. 
     Next, the current embodiment of the configuration of rearward surface  812  of attachment foot  406  with respect to outer surface  610  of clamp level  604  is described. The side circumference  908  of attachment foot  406  may be designed with a generally angular configuration. Top half  912  of side circumference  908  may angle generally downwardly and away from top surface  914  of attachment foot  406  to form a top half angled surface  902   c . Bottom half  916  of side circumference  908  may angle generally upwardly and away from a bottom surface  918  of attachment foot  406  to form a bottom half angled surface  902   d . Top half angled surface  902   c  and bottom half angled surface  902   d  are configured to diverge at a point  906 . 
     Outer surface  610  of clamp lever  604  is designed to mate in complimentary fashion with the design configuration of top half angled surface  902   c  and bottom half angled surface  902   d . Angled surfaces of outer surface  610  include a top half angled surface  604   b  and a bottom half angled surface  604   a  that diverge at point  920 . Accordingly, top half angled surface  604   b , bottom half angled surface  604   a  and point  920  of contact surface  610  are formed in a complimentary configuration to mate with the angular design of corresponding top half angled surface  902   c , bottom half angled surface  902   d  and point  906 , respectively. 
     In operation, when clamp lever  604  is pivoted about pin  606  to bring outer surface  610  into contact with rearward surface  812  of attachment foot  406 , top half angled surface  902   b , bottom half angled surface  902   a  and point  910  of attachment foot  406  mate with top half angled surface  802   b , bottom half angled surface  802   a  and point  904  of forward front surface  804 , respectively. In this manner, forward front contact surface  804  and in combination with side contact surfaces  802  provide an alignment mechanism of marker carrier body  112  of the disclosed invention. This ensures that any marker carrier body  112  employing the designed receiving area  402  and front contact surface  804  in combination with side contact surfaces  802  will always be in the same position, location and/or orientation when mounted on the disclosed attachment foot  406  having complimentary forward surface  806  and angular contact surfaces  810  after articulated arm  128  is set into a final position. Likewise, top half angled surface  604   b , bottom half angled surface  604   a  and point  920  of contact surface  610  mate with the angular design of corresponding top half angled surface  902   c , bottom half angled surface  902 d and point  906  of attachment foot  406 , respectively. 
       FIGS. 10 and 11  illustrate alternate embodiments of the attachment foot  406  and clamp lever  604  design. Turning to  FIG. 10 , a cross-sectional view of attachment foot  406  is disposed within receiving area  402 . A medical drape  700  may be disposed over attachment foot  406  within receiving area  402 . The side circumference  710  of attachment foot  406  may be designed with a generally multi-angular configuration. Thus a top half  712  of the side circumference  710  may angle generally downwardly and away from a top surface  716  of attachment foot  406  to form a top half angled surface  406   b . A bottom half  714  of the side circumference  710  may angle generally upwardly and away from a bottom surface  718  of attachment foot  406  to form a bottom half angled surface  406   a . Top half angled surface  406   b  and bottom half angled surface  406   a  are configured to diverge into a point  702 . 
     The side wall surface  1012  of receiving area  402  is configured to mate with the surface of side circumference  710 . An angular side surface  1002  of side wall surface  1012  is designed at a complimentary angle to mate in complimentary fashion with the bottom half angled surface  406   a . Thus, surfaces of side wall surface  1012  include a wall  1006  extending downwardly and generally perpendicular from a top surface  1008  of receiving area  402 . Side wall surface  1012  also includes angular side surface  1002  angled downwardly and inwardly from a point  1010  extending from a bottom of wall  1006 . Accordingly, angular side surface  1002  and point  1010  of side wall surface  1012  are formed in a complimentary configuration to mate with the angular design of corresponding bottom half angled surface  406   a  and point  702 , respectively. 
     Next, the current embodiment of the configuration of outer surface  608  of attachment foot  406  with respect to outer surface  610  of clamp level  604  is described. The side circumference  710  of attachment foot  406  may be designed with a generally multi-angular configuration. Top half  712  of side circumference  710  may angle generally downwardly and away from top surface  716  of attachment foot  406  to form a top half angled surface  406   c . Bottom half  714  of side circumference  710  may angle generally upwardly and away from a bottom surface  718  of attachment foot  406  to form a bottom half angled surface  406   d . Top half angled surface  406   c  and bottom half angled surface  406   d  are configured to diverge at a point  706 . 
     Outer surface  610  of clamp lever  604  is designed to mate in complimentary fashion with the design configuration of bottom half angled surface  406   d . Outer surface  610  includes a wall  1014  extending downwardly and generally perpendicular from a top surface  1012  of clamp lever  604 . Outer surface  610  also includes angular side surface  1000  angled downwardly and inwardly from a point  1004  extending from a bottom of wall  1014 . Accordingly, angular side surface  1000  and point  1004  of outer surface  610  are formed in a complimentary configuration to mate with the angular design of corresponding bottom half angled surface  406   d  and point  706 , respectively. 
     In operation, when clamp lever  604  is pivoted about pin  606  to bring outer surface  610  into contact with outer surface  608  of attachment foot  406 , bottom half angled surface  406   a  and point  702  of attachment foot  406  align with angular side surface  1002  and point  1010  of side wall surface  1012 , respectively. Likewise, top half angled surface  604   b , bottom half angled surface  604   a  and point  708  of contact surface  610  mate with the angular design of corresponding top half angled surface  406   c , bottom half angled surface  406   d  and point  706  of attachment foot  406 , respectively. In a final assembly, top surface  716  of attachment foot  406  may be abutted against top surface  1008  of receiving area  402  to secure attachment foot  406  within receiving area  402 . In this manner, this ensures that any marker carrier body  112  employing the designed receiving area  402  of  FIG. 10  will always be in the same position, location and/or orientation when mounted on the disclosed attachment foot  406  of  FIG. 10  after articulated arm  128  is set into a final position. 
     Turning to an alternate embodiment depicted in  FIG. 11 , a cross-sectional view illustrates attachment foot  406  disposed within receiving area  402 . A medical drape  700  is disposed over attachment foot  406  within receiving area  402 . The side circumference  710  of attachment foot  406  may be designed with a generally angular configuration. A side profile of attachment foot  406  generally represents a trapezoidal shape wherein a top surface  1118  is slightly longer than a bottom surface  1120  of attachment foot  406 . As shown, top surface  1118  is connected to bottom surface  1120  via a generally downwardly and inwardly angular wall surface  1102  disposed near angular side wall  1104  of receiving area  402 . Point  1114  is formed at the joint wherein angular wall surface  1102  extends from top surface  1118 . Angular side wall  1104  extends from a top surface  1112  of receiving area  402 . Angular side wall  1104  may extend downwardly and inwardly at an angle complimentary to the angle formed by angular wall surface  1102 . Point  1116  is formed at the joint wherein angular side wall  1104  extends from top surface  1112  of receiving area  402 . 
     Likewise, top surface  1118  is connected to bottom surface  1120  via a generally downwardly and inwardly angular wall surface  1106  disposed near outer surface  610  of clamp lever  604 . Outer surface  610  may form an angular surface  1108  generally complimentary to the angle formed by angular wall surface  1106 . In operation, when clamp lever  604  is pivoted about pin  606  to bring angular surface  1108  into contact with angular wall surface  1106  of attachment foot  406 , angular wall surface  1102  is brought into alignment with angular side wall  1104  and point  1114  meets with point  1116  in the aligned configuration. Additionally, angular surface  1108  is aligned with angular wall surface  1106 , and top surface  1118  abuts top surface  1112  to retain attachment foot within fixed position of receiving area  402 . In this manner, this ensures that any marker carrier body  112  employing the designed receiving area  402  of  FIG. 11  will always be in the same position, location and/or orientation when mounted on the disclosed attachment foot  406  of  FIG. 11  after articulated arm  128  is set into a final position. 
     Given the improved features provided by embodiments of the disclosed referencing device  100 , a method for preparing an image-guided, surgical navigation system is outlined herein. Turning to  FIG. 14 , a technique  1400  for preparing and utilizing an image-guided surgical navigation according to disclosed embodiments is depicted. Step  1402  requires fixing attachment unit  132  of referencing device  100  onto a patient. Step  1404  includes installing marker carrier body  112  onto connection unit  126 . This may include adjusting components of connection unit  126  into a preferred position to orient marker carrier body  112  into a prescribed location, position and/or orientation. Adjustment of connection unit  126  may include manipulating arm extensions  118 ,  122  and joints  120 ,  124 ,  408 , as necessary. Once an acceptable position is achieved, for example, an acceptable position of articulated arm  128  and orientation of marker carrier body  112 , the articulated arm may be locked into a final position via locking mechanism  136  to secure the orientation of referencing device  100 . Step  1406  includes registering a position and orientation of referencing device  100 . This may include specifically registering a location, position and/or orientation of marker carrier unit  116 . Having connection unit  126  locked into position, claim lever  604  may act as a detachment mechanism for releasing marker carrier body  112  from attachment foot  406 . Accordingly, step  1408  includes detaching marker carrier body  112  from connection unit  126 . Step  1410  provides draping the patient and connection unit  126  of referencing device  100 . Disclosed embodiments provide that connection unit  126  includes articulated arm  126  including joint  408  and attachment foot  406 . As illustrated in, at least,  FIGS. 7, 9, 10, and 11 , medical drape  700  is disposed over attachment foot  406  (and in a final assembly within receiving area  402 ). Step  1412  includes attaching a sterile marker carrier body  112  to connection unit  126 . The sterile marker carrier body  112  may be the previous marker carrier body  112  which has since been sterilized, or it may be another sterile marker carrier body  112 . A design of the disclosed marker carrier body  112  provides a uniquely configured receiving area that automatically locates, positions and orients marker carrier body  112  on a mountable attachment foot  406  in a complimentary mated fashion. The disclosed design consistently orients marker carrier body  112  to a repeatable prescribed position mounted on a complimentary configured attachment foot  406 . The mounting and securing of marker carrier body  112  includes a feature of positioning and affixing medical draping in a secure and consistent manner Once a sterile marker carrier body  112  is fixed mounted to connection unit  126 , step  1414  includes starting a navigation procedure via an image-guided surgery (IGS). 
     Having described the many embodiments of the present invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the present invention defined in the appended claims. For example, disclosed embodiments may provide certain indicia and/or colors on components of the disclosed invention such as, but not limited to, marker carrier unit  116 , marker carrier body  112 , and attachment foot  406 . In one example, the aforementioned indicia and/or colors may correspond to a specific use or application associated with said indicia and/or colors. Such specific uses or applications associated with said indicia and/or colors may be employed, for example, in specific prescribed distinct surgical procedures or in certain environments or medical situations. These may include, but not limited to, for example, use in neuro and ENT surgery, spinal applications, soft/sensitive tissue applications and/or applying force applications. Furthermore, it should be appreciated that all examples in the present disclosure, while illustrating many embodiments of the present invention, are provided as non-limiting examples and are, therefore, not to be taken as limiting the various aspects so illustrated. 
     While the present invention has been disclosed with references to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the spirit and scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.