Patent Publication Number: US-2021161554-A1

Title: Medical instrument guidance systems and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 62/942,803, filed Dec. 3, 2019, the contents of which are incorporated herein in their entirety. 
    
    
     TECHNICAL FIELD 
     This document pertains generally, but not by way of limitation, to surgical instruments and methods for inserting and guiding instruments used to perform percutaneous medical procedures. More specifically, but not by way of limitation, the present application relates to systems and methods for inserting and guiding minimally invasive insertion instruments such as laparoscopic access needles. 
     BACKGROUND 
     Many surgical procedures involve the treatment or removal of subdermal target tissue, e.g., diseased or unwanted tissue or growths, located inside of a patient. As such, these procedures require access to the internal anatomy of the patient via an open procedure or through a smaller opening in minimally invasive procedures. In minimally invasive procedures, a surgeon guides an insertion instrument, such as an access needle, into the epidermis of the patient along a trajectory to introduce a tip of the access instrument into a surgical site within a chest or abdominal cavity of the patient. Imaging of the anatomy of the patient can be used to plan the trajectory of the insertion needle. However, interpretation of the imaging and placement of the access needle can be difficult such that sometimes an interventional radiologist performs the access needle placement rather than the surgeon that performs the medical procedure. 
     Examples of surgical instruments are described in U.S. Pat. No. 4,610,663 to Rosenberg; U.S. Pat. No. 9,737,232 to Fan; and Pub. No. US 2017/0303940 A1 to Sperry et al. 
     Overview 
     The present inventor has recognized, among other things, that problems to be solved in performing medical procedures include the inconvenience of a surgeon having to utilize an interventional radiologist to perform access needle insertion. Use of such specialists significantly prolong the surgical procedure because the access needle is typically placed the day before the medical procedure by the interventional radiologist. Furthermore, the present inventor has recognized that use of real-time guided navigation of access instruments is typically not feasible due to impracticality of using imaging equipment in real time, including exposure of the patient and surgeon to radiation. Additionally, movement and breathing of the patient can make interpretation of still images and real-time imaging of the patient difficult. 
     The present subject matter can provide solutions to these problems and other problems, such as by providing systems and methods that include instrument guidance pads that can provide real-time feedback of the location and orientation of an access instrument during the placement procedure. The instrument guidance pads can include hardware for displaying indicia that can be updated in real-time indicative of the location of a surgical instrument such as an access needle. The guidance pad can react directly to the presence of the access needle such that a separate imaging system is not required. In examples, the guidance pad can further provide guidance information, such as a desired orientation of the access needle and no-go zones for the access needle. In examples, the guidance pad can include sensors for providing indicia of tissue and anatomy of the patient. Methods of performing surgical procedures with such guidance pads are also described herein. 
     In an example, a guidance system for performing a percutaneous access incision can comprise an access needle comprising a shaft and a tip located at a distal end of the shaft, and a guidance pad comprising a dermal side, an outward side, an opening to receive the access needle, the opening extending between the dermal side and the outward side, and a feedback device viewable from the outward side to provide an indication of a depth of the tip beneath the guidance pad and a trajectory of the shaft from the opening. 
     In another example, a method for planning guidance of an access needle into a patient in preparation for a minimally invasive surgical procedure comprises determining a location for an access point on the patient, positioning a guidance pad over the access point, inserting a tip of the access needle through the pad, and displaying guidance information on the guidance pad. 
     In an additional example, a guidance pad for guiding an access needle into a patient in preparation for a minimally invasive surgical procedure comprises a dermal side, a outward side, a opening to receive the access needle, the opening extending between the dermal side and the outward side, and an array of light emitters surrounding the opening and viewable from the outward side to provide an indication of a depth of a tip of the access needle beneath the guidance pad and a trajectory of a shaft of the access needle from the opening, wherein each of the light emitters of the array has a variable property. 
     This overview is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of a kidney in an abdominal cavity taken in a coronal plane. 
         FIG. 2  is a schematic illustration of kidneys in an abdominal cavity taken in a transverse plane. 
         FIG. 3  is a schematic illustration of a guidance pad of the present disclosure being used to orient an access needle into an abdominal cavity. 
         FIG. 4  is a top view of a first example of a guidance pad using light-emitting diodes to provide depth and distance feedback. 
         FIG. 5  is a side schematic view of an insertion needle inserted into the guidance pad of  FIG. 4  at a first depth and a first orientation. 
         FIG. 6  is a top view of the guidance pad of  FIG. 5  showing visual feedback indicative of the first depth and the first orientation. 
         FIG. 7  is a side schematic view of an insertion needle inserted into the guidance pad of  FIG. 4  at a second depth and a second orientation. 
         FIG. 8  is a top view of the guidance pad of  FIG. 7  showing visual feedback indicative of the second depth and the second orientation. 
         FIG. 9  is a top view of a second example of a guidance pad using an ultrasound-enabled insertion needle with a guidance pad incorporating a visual display. 
         FIG. 10  is a schematic illustration of an insertion needle having a transducer for interacting with the guidance pad of  FIG. 9 . 
         FIG. 11  is a schematic line diagram illustrating methods for performing surgical procedures using a guidance pad of the present disclosure to insert an access needle. 
     
    
    
     In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document. 
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic illustration of kidney K in abdominal cavity AC taken in a coronal plane. The coronal plane can be defined by axis Y in the medial-lateral direction and axis Z in the superior-inferior direction.  FIG. 2  is a schematic illustration of kidneys K in abdominal cavity AC taken in a transverse plane. The transverse plane can be defined by axis Y in the medial-lateral direction and axis X in the anterior-posterior direction.  FIGS. 1 and 2  are be discussed concurrently. 
     Abdominal cavity AC can be defined by epidermal layers E that provide a barrier to access of kidney K. Instrument I can be inserted through epidermal layers E and into kidney K. Kidney K can comprise outer cortex Cx, medulla M and calyces Cy. Kidney stones can form in kidney K is various places, particularly in calyces Cy. A surgical procedure to remove kidney stones can comprise use of stone fragmentation and stone retrieval devices that are inserted through an opening in epidermal layers E provided by an access needle. The access needle can be used to provide orientation to a guide tube, such as a laparoscope. As such, in order to perform a surgical procedure to remove kidney stones, the access needle must be blindly guided into kidney K through epidermal layers E and into calyces Cy, typically using only two-dimensional imaging. As such, the surgeon must mentally interpret the imaging and transfer desired position and orientation information from the imaging onto the patient to find the kidney and avoid other organs. As can be seen in  FIG. 1 , the orientation of instrument I in the coronal plane can be influenced by the location of calyces Cy where kidney stones typically form. As can be seen in  FIG. 2 , the orientation of instrument I in the transverse plane can be influenced by the location of spine Si and other organs, such as the lungs, liver L and spleen Se. Thus, the initial trajectory of an access instrument used to place instrument I in abdominal cavity AC is important. Placement of the access instrument can be further complicated by movement or breathing of the patient. 
     The present disclosure provides systems and method for providing indicia and feedback regarding the location of instruments relative to the space underneath epidermal layer E and the locations of anatomy of the patient. The systems and methods can include the use of a guidance pad that can provide real-time feedback to a surgeon, or other personnel, regarding the orientation and depth of the instrument, particularly the tip, relative to the guidance pad and the anatomy of the patient. Note, although the present application is described with reference to nephrolithotomy procedures, the systems and methods of the present disclosure can be used in other procedures, such as those used to remove tumors including laparoscopic tumor ablation procedures. 
       FIG. 3  is a schematic illustration of guidance pad  10  of the present disclosure being used to orient access needle  12  into an abdominal cavity underneath skin  14  of a patient. Pad  10  can comprise a mat having inner (dermal side) surface  16  that can be placed against skin  14  and outer (outward indicia) surface  18  from which indicia  20  can be read by an operator or user of guidance pad  10 . Pad  10  can comprise port  22  through which access needle  12  can positioned. 
     Guidance pad  10  can be made of a uniform material or can be made of a plurality of layers. Thickness t of guidance pad  10  can correspond to the construction of guidance pad  10 . It can be desirable to minimize thickness t in order to increase pliability and flexibility of guidance pad  10  such that guidance pad  10  can conform to the contours of skin  14 . Indicia  20  can be formed by a layer of pad  10  or by additional components added to outer surface  18 , as discussed in greater detail with respect to  FIGS. 5 and 7 . Guidance pad  10  can additionally include an adhesion layer to abut skin  14  to immobilize guidance pad  10  relative to the patient. Guidance pad  10  can be configured to be disposable or reusable. As such, guidance pad  10  can include additional protective layers to encapsulate components for forming indicia  20 , such as light emitters or a display screen, to facilitate cleaning and sterilization and the reapplication of an adhesive layer. 
     Port  22  can comprise an opening through guidance pad  10  from inner surface  16  to outer surface  18 . Port  22  can be reinforced with ring  24  to provide port  22  with rigidity and a size to match that of access needle  12 . Thus, the internal diameter of ring  24  can be minimized to match the size of needle  12  to maximize the display area of outer surface  18  and to provide some holding (immobilizing) capability of needle  12 . In the illustrated example, access needle  12  and port  22  are circular. However, needle  12  and port  22  can be provided with other shapes, matching or otherwise. Likewise, in the illustrated example, guidance pad  10  has a circular outer perimeter. However, the outer perimeter of guidance pad  10  can have other shapes. A circular outer perimeter of guidance pad  10  can be useful for providing uniform information relative to port  22 ; for example, all portions of the outer perimeter of wall  28  can be equidistant from port  22 . Guidance pad  10  can be sized to cover a surface are of the patient sufficient to cover the distance between a desired incision point in the patient and target tissue where treatment is to be performed, such as the location of a tumor or kidney stones. As such, port  24  need not be located at the center of guidance pad  10 , but can be located at a periphery to maximize the distance between access port  24  and the periphery. Such a configuration can be useful in procedures where the general direction of the target anatomy from the access incision is known. 
     Outer surface  18  can be provided with markings  26  to facilitate interpretation of indicia  20 . For example, markings  26  can comprise a grid system, a Cartesian coordinate system, a polar coordinate system and the like. Port  22  can be the origin of the coordinate systems. Indicia  20  can be provided on markings  26  to provide multiple pieces of information regarding access needle  12 . In particular, indicia  20  can provide 1) an indication of the distance that a tip of access needle  12  (not visible in  FIG. 3 ) is from port  22 ; 2) an indication of the trajectory of access needle  12  relative to port  22 ; and 3) an indication of the depth of the tip of access needle  12  below guidance pad  10 . The visual information provided by indicia  20  can be in the form of color-coded light or light of different intensities, as discussed with reference to  FIGS. 4-8 , or in the form of images or illustrations provided on a display screen, as discussed with reference to  FIG. 9 . 
       FIG. 4  is a top view of guidance pad  30  comprising array  32  of light-emitting elements that can be configured to provide depth and distance feedback to a user of guidance pad  30 . Guidance pad  30  can comprise an example of guidance pad  10  of  FIG. 3 . Guidance pad  30  can comprise outer surface  34 , markings  36  and port  38 . Array  32  of light-emitting elements can include a plurality of individual light emitters that are arranged in an organized pattern on outer surface  34  such that the way (e.g., pattern, intensity, color) the light emitters are lit up or not lit up can convey visual information to the user. Markings  36  can comprise a grid system, a Cartesian coordinate system, a polar coordinate system and the like, that can be configured to indicate two- or three-dimensional space relative to port  38 . 
     In the illustrated example, array  32  defines a plurality of columns of light emitters extending radially from a center within port  38  and markings  36  comprise a Cartesian coordinate system including X and Z axes that can, for example, correspond to the X, Y and Z axes of  FIGS. 1 and 2 . The light emitters can light up to correspond to a position of an instrument inserted through port  38 . In an example, each light emitter can be off (black in  FIGS. 4, 6 and 8 ) when not conveying any position information. The light emitter can turn on to indicate the presence of the instrument below pad  30 . The brightness or color of each light emitter can convey distance away from pad of the instrument.  FIG. 4  illustrates sixteen columns  40 A- 40 P of light emitters, each column having five light emitters. For example, column  40 A can comprise light emitters  42 A- 42 E. However, the particular number of light emitters in array  32  can vary in different embodiments depending on the granularity of information that is to be obtained. Likewise, the spacing between lines of the grid of markings  36  can vary in different embodiments depending on the granularity of information that is to be obtained. 
     As discussed, guidance pad  30  can be constructed in a variety of different ways to be reusable or disposable. In an example, light emitters of array  32  can comprise light-emitting diodes (LEDs) mounted to a flexible circuit comprising a layer of guidance pad  30 . The LEDs can be sealed behind a protective layer. The flexible circuit can be coupled to an embedded controller or an external controller that can control operation of the LEDs based on the location of an instrument inserted into port  38 . For example, the flexible circuit can include a magnetic field sensor for each of the LEDs and an instrument can include a magnet proximate the distal tip of the instrument. As such, the strength of the magnetic field detected by each magnetic field sensor can be influenced by the proximity of the distal tip of the instrument to each LED. The brightness or color of each LED can be programmed to change based on the proximity of the magnet. For example, for no magnetic field the LED can be off, for an adjacent magnet the LED can be on and fully bright. However, in other examples, the LEDs can be programmed to react to different inputs, such as ultrasonic information or other proximity sensor information. 
       FIG. 5  is a side schematic view of insertion needle  46  inserted into guidance pad  30  of  FIG. 4  at a first depth, indicated by distance D 1 , and a first orientation, indicated by angle α 1 .  FIG. 6  is a top view of guidance pad  30  of  FIG. 5  showing visual feedback  48  indicative of the first depth and the first orientation. Guidance pad  30  can comprise backing  50 , adhesive layer  52  and display layer  54 . Insertion needle  46  can comprise shaft  56  and tip  58 .  FIGS. 5 and 6  are discussed concurrently. 
     Shaft  56  of insertion needle  46  can be inserted into port  38  such that tip  58  is positioned distance D below guidance pad  30 . Shaft  56  can be angled relative to plane P of guidance pad  30  at angle α 1 . Array  32  of light-emitting elements can react to the location of shaft  56  and tip  58 . In the example illustrated in  FIG. 6 , insertion needle  46  can be located closest to column  40 J of array  32  such that light emitters of column  40 J can comprise visual feedback  48 . Column  40 J can comprise light emitters  60 A- 60 E. Column  40 J can correspond to insertion needle  46  extending into port  38  at angle β 1  relative to the X axis. 
     Activation of at least one of light emitters  60 A- 60 E of column  40 J can provide an indication of angle β 1  for shaft  56 . As can be seen in  FIG. 5 , shaft  56  is inserted into port  38  such that tip  58  does not extend to periphery  62  of guidance pad  30 . As such, all of light emitters  60 A- 60 E do not activate. For example, light emitters  60 E and  60 D closest to periphery  62  do not light up and light emitters  60 A- 60 C closest to port  38  are activated. The degree to which light emitters  60 A- 60 C are activated can provide an indication of both angle α 1  and depth D 1 . For example, light emitter  60 A can be activated a first degree to show the presence of the portion of shaft  56  just below guidance pad  30  and light emitter  60 C can be activated a second degree to show the presence of tip  58  further below guidance pad  30 . In an example, light emitter  60 C can be brighter than light emitter  60 A to indicate where the greatest depth of shaft  56  and to indicate where tip  58  is located. Light emitter  60 B can be activated to a degree in between the first and second degrees such that a continuous spectrum or a gradual changing of light emitting activation can be provided. As mentioned in other examples, color can be used to indicate depth. For example, a heat map could be used where subsequently greater depth can be indicated by the colors blue, green, yellow and red. 
       FIG. 7  is a side schematic view of insertion needle  46  inserted into guidance pad  30  of  FIGS. 5 and 6  at a second depth, indicated by distance DE, and a second orientation, indicated by angle α 2 .  FIG. 8  is a top view of guidance pad  30  of  FIG. 7  showing visual feedback  64  indicative of the second depth and the second orientation.  FIGS. 7 and 8  are discussed concurrently. 
     Shaft  56  of insertion needle  46  can be inserted into port  38  such that tip  58  is positioned distance D 2  below guidance pad  30 , with D 2  being greater than D 1  of  FIG. 5 . Shaft  56  can be angled relative to the plane of guidance pad  30  at angle α 2 , with α 2  being less than α 1 . In the example illustrated in  FIG. 7 , insertion needle  46  can be located closest to column  40 L of array  32  such that light emitters of column  40 L can comprise visual feedback  64 . Column  40 L can comprise light emitters  66 A- 66 E. Column  40 L can correspond to insertion needle  46  extending into port  38  at angle β 2  relative to the X axis, with β 2  being less than β 1 . 
     Activation of at least one of light emitters  66 A- 66 E of column  40 L can provide an indication of angle β 2  for shaft  56 . As can be seen in  FIG. 7 , shaft  56  is inserted into port  38  such that tip  58  extends to periphery  62  of guidance pad  30 . As such, all of light emitters  66 A- 66 E can be activated to some degree. For example, light emitter  60 E closest to periphery  62  and light emitter  60 A closes to port  38  can be activated in opposite manners to indicate the depth and orientation of shaft  56 . The degree to which light emitters  66 A- 66 D are activated can provide an indication of both angle α 2  and depth D 2 . For example, light emitter  66 A can be activated a first degree to show the presence of the portion of shaft  56  just below guidance pad  30  and light emitter  60 E can be activated a second degree to show the presence of tip  58  further below guidance pad  30 . In an example, light emitter  60 E can be brighter than light emitter  60 A to indicate where the greatest depth of shaft  56  and to indicate where tip  58  is located. Light emitters  60 B- 66 D can be activated to varying degrees in between the first and second degrees such that a continuous spectrum or a gradual changing of light emitting activation can be provided. 
     Light emitters of array  32  can update in real-time to indicate the location and depth of tip  58  below plane P of guidance pad  30 . Thus, as a surgeon can manipulate shaft  56  and can receive an indication of how far tip  58  is located below skin  14  ( FIG. 3 ) of the patient. In an example, markings  36  can include a scale to convert indicia of the light emitters to an actual length. For example, with reference to light emitters  66 A- 66 E of  FIG. 8 , black could indicate a depth of zero and white could indicate the full length of shaft  56  between tip  58  and a handpiece (now shown). In other examples, shaft  58  can be provided with markings that correspond to the depth and indicia from the guidance pad can be used to provide corroborating depth information along with orientation (e.g., angle α 1  and angle β 1 ) information. In another example, one of the light emitters can be pre-activated to a desired intensity or color to provide target depth and orientation information to which a surgeon is to guide tip  58 . As such, guidance pad  30  can be configured to provide both passive and active guidance information. Furthermore, as discussed below with reference to  FIGS. 9 and 10 , guidance pads of the present disclosure can additionally be configured to provide passive and active anatomic information. 
       FIG. 9  is a top view of guidance pad  70  incorporating a visual display being used in conjunction with sensor-enabled, e.g., ultra-sound-enabled, insertion needle  72 . Guidance pad  70  can comprise an embodiment of guidance pad  10  of  FIG. 3 . Guidance pad  70  can comprise display screen  74  extending between port  76  and periphery  78 . Guidance pad  70  can be connected to controller  80 . Controller  80  can be connected to guide pad  70  via cable  82  or can be incorporated directly into guide pad  70 . Insertion needle  72  can comprise top  84  and shaft  86 . 
     Display screen  74  can comprise a layer of guide pad having the same shape as guide pad  70 . Display screen  74  can be positioned above an adhesive layer and an electronics layer and below a protective layer. Display screen  74  can comprise an active display unit, such as a liquid crystal display, a plasma screen, an organic light-emitting diode display and the like. As such, display screen  74  can be configured to display images from different inputs utilizing controller  80 . For example, controller  80  can receive input from sensor-enabled insertion needle  72 . Controller  80  can interpret information contained in at least on of electronic, digital, and mechanical signals from sensor  96  ( FIG. 10 ) and display images on display screen  74 . The information from sensor-enabled insertion needle  72  can be used to interpret the position and orientation of shaft  86  and to generating imagery of tissue and anatomy surrounding insertion needle  72 . For example, display screen  74  can show kidney  88 , spinal column  90 , instrument  92  and boundary  94 . 
       FIG. 10  is a schematic illustration of insertion needle, or access needle,  72  having sensor  96  for interacting with guidance pad  70  of  FIG. 9 . Insertion needle  72  can comprise tip  84 , shaft  86 , sensor  96 , lumen  97  and handpiece  98 . Insertion needle  72  can be configured for use with any of the guidance pads disclosed herein. 
     Shaft  86  can extend from proximal end  99 P to distal end  99 D. Handpiece  98  can be located at or near proximal end  99 P and can comprise any suitable device configured to facilitate insertion needle  72 . In other examples, handpiece  98  can be omitted. Tip  84  can be located at distal end  99 D of shaft  86 . Tip  84  can be integral with shaft  86  or a separate piece. Tip  86  can comprise a device to facilitate puncturing of tissue, such as skin, e.g., epidermal layers E ( FIGS. 1 and 2 ). Thus, tip  86  can comprise a sharp point, such as a needle point, or a sharp edge, such as a scalpel or razor blade. Lumen  97  can be configured to extend the length of insertion needle  72 . Lumen  97  can extend through handpiece  98 , shaft  86  and tip  84 . However, lumen  97  can extend out of the side of shaft  86  without extending through handpiece  98 . Likewise, lumen  97  can be configured to extend out of the exact distal end of tip  84  to more closely track with an incision point made with tip  84 , but is shown offset for illustrative purposes. Lumen  97  can be used to insert other instrumentation into the patient after insertion needle  72  has been positioned in a desired location and orientation within a patient. For example, a guidewire can be placed into lumen  72  to mark the path of insertion needle  72 . Thereafter, insertion needle  72  can be removed while the guide wire remains in place. Thus, the guidewire can be used to guide other instruments, such as dilator tubes and a laparoscope tube, to the surgical site determined by insertion needle  72 . 
     Sensor  96  can be integrated into the construction of insertion needle  72 . Sensor  96  can be included in shaft  86  or tip  84 . Sensor  96  can be located at tip or proximate tip  84  or a predetermined or known distance from tip  84 . In examples, tip  84  can be constructed of a sensor such that separate sensors and tips are not used. Sensor  96  can comprise a device configured to provide an indication of the location of tip  84 . Sensor  96  can comprise a passive or active. In an example, top  84  can comprise a magnet that continuously emits a passive magnetic signal. In another example, sensor  96  can comprise an ultrasound transducer that selectively emits an active signal. In other examples, sensor  96  can comprise a position sensor or a proximity sensor, such as a capacitive sensor or a photoelectric sensor. In additional embodiments, sensor  96  can comprise a combination of different sensors. Controller  80  can be configured to receive output of sensor  96  either directly or indirectly with the use of additional receiving components. For example, controller  80  can be connected to magnetic field sensors (e.g., Hall effect sensors or microelectromechanical system (MEMS) sensors) associated light emitters of guidance pad  30 . In the embodiment of  FIG. 10 , sensor  96  can be configured as an ultrasonic transducer, the output of which can be read by controller  80 . 
     Returning to  FIG. 9 , with insertion needle  72  inserted into port  76  such that tip  84  is behind (relative to  FIG. 9 ), guidance pad  70  can detect the presence of sensor  96  and can activate display screen  74  to show a visual rendition of shaft  54  as instrument  92 . Likewise, the ultrasound output of sensor  96  can be used to obtain imaging of anatomy, such as a liver and spine, and show visual renditions of kidney  88  and spinal column  90  on display screen  74 . As such, the guidance system provided by guidance pad  70  and insertion needle  72  can provide visual indicia of the location of tip  84  within a patient relative to anatomy of the patient. Furthermore, as discussed with reference to  FIG. 11 , guidance information relating to the desired orientation of insertion needle  72  as well as locations where insertion needle  72  should not be positioned, such as no-go zone indicated by boundary  94 , can be included in a surgical plan that can be visually displayed on display screen  74 . 
       FIG. 11  is a line diagram illustrating method  100  for performing surgical procedures according the present disclosure. The surgical procedure can comprise an open procedure or a minimally invasive procedure. However, the disclosure is particularly well-suited for procedures making blind insertions of surgical instruments, such as laparoscopic procedures.  FIG. 11  is discussed with reference to performing a Percutaneous Nephrolithotomy (PCNL) procedure using a laparoscope inserted into a tube placed with dilators and an insertion needle. In a PCNL procedure, kidney stones (nephrolithiasis) are removed from a kidney after being fragmented into small pieces suitable for extraction through the tube. Kidney stones of a variety of shapes and sizes typically form in the calyces of the kidney. As such, it is desirable to guide extraction instrumentation to the calyces to minimize movement and repositioning of the removal instrumentation or the need to produce a second insertion needle. Although  FIG. 11  is described with reference to nephrolithotomy procedures, the systems and methods of the present disclosure can be used in other procedures, such as those used to remove tumors including laparoscopic tumor ablation procedures. 
     At step  102 , medical images of a patient can be obtained. The medical images can be taken to obtain views of anatomy of the patient including a surgical location where an instrument is to be positioned. In particular, the abdominal cavity of the patient can be imaged to obtain views of a kidney and the locations of kidney stones within the kidney. The views can be taken in multiple planes, such as the coronal (Y-Z plane of  FIG. 1 ), transverse (Y-X plane of  FIG. 2 ) and sagittal planes. Three-dimensional imaging can also be obtained. Types of imaging that can be used include x-ray, Computed tomography (CT) scan, magnetic resonance imaging (MRI), ultrasound, and the like. The imaging can be obtained at the site where the surgical procedure is to be performed, such as a hospital, or at an outpatient facility. 
     At step  104 , target anatomy in the imaging can be identified. For example, kidney K ( FIG. 1 ) and kidney stones within kidney K can be identified. The locations of the kidney stones can be recorded and translated into three-dimensional coordinate locations, such as with respect to the X, Y and Z planes defined in  FIGS. 1 and 2 . The X, Y and Z coordinates can be determined by piecing together information from multiple two-dimensional imaging views of the patient. 
     At step  106 , an incision point in the patient can be determined. The incision point can be a location on the epidermis of the patient where an access instrument, e.g., instrument I ( FIGS. 1 and 2 ), access needle  12  ( FIG. 3 ), access needle  46  ( FIGS. 5 and 7 ) and insertion needle  72  ( FIG. 10 ), can be positioned to reach the target anatomy, such as the calyces of the kidney, without intersecting any anatomy not intended to receive the access needle, such as the spine, liver and lungs. The location of the incision point can be recorded and translated into three-dimensional coordinate locations, such as with respect to the X, Y and Z planes defined in  FIGS. 1 and 2 . 
     At step  108 , a trajectory for an insertion instrument can be determined. For example, the trajectory between the target anatomy and the incision point can be determined using the three-dimensional coordinate system. The trajectory of the instrument can be recorded and translated into three-dimensional coordinate locations, such as with respect to the X, Y and Z planes defined in  FIGS. 1 and 2 . 
     In other examples, the incision point can be determined by first planning a trajectory from the target anatomy to the epidermis (e.g., steps  106  and  108  can be performed in reverse order). In either example, the trajectory can be plotted to avoid intersecting other anatomy of the patient, such as the spinal column, liver, spleen and the like. Accordingly, no-go zones, such as the area cordoned off by boundary  94  in  FIG. 9 , can be identified and recorded in the three-dimensional coordinate system. 
     At step  110 , a surgical plan can be saved including information specific to the patient and the target anatomy for performing the medical procedure. The surgical plan can include the locations of the target anatomy, the incision, the insertion instrument trajectory and the no-go zones. All of these pieces of information can be recorded as visual indicia that can be configured for display on a guidance pad for viewing by a surgeon during the surgical procedure. 
     The surgical plan can be saved electronically on a computer or machine readable medium. The term “machine readable medium” may include any medium that is capable of storing, encoding, or carrying instructions for execution by a machine and that cause the machine to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine-readable medium examples include solid-state memories, and optical and magnetic media. In examples, the machine can be embodiments of guidance pads described herein, such as guidance pads  10 ,  30  and  70 , or controller  80 . In other examples, the machine can be a surgical imaging system, a surgical navigation system or a personal computer and the like. In examples, the surgical plan can be stored in a format for rendering a visual display to include indicia indicative of the patient, the anatomy, the target location, the incision location, no go zones, and the insertion instrument trajectory. 
     Steps  102 - 110  can describe a method of planning a surgical procedure. In particular, the steps can describe a method of planning an insertion of laparoscope for performing a PCNL procedure using an insertion or access needle. 
     At step  112 , a guidance pad, such as one or more of guidance pads  10 ,  30  and  70 , can be aligned with a patient. In particular, the planned incision point for the patient can be aligned with an opening in the guidance pad, such as ports  24 ,  38  and  76 . Ports  24 ,  38  and  76  can thus act as registration points that register the coordinate system of the anatomy with the patient. For example, the planned incision point can be located visually on the outside of the patient by comparing with the imaging. Thus, the guidance pad can be placed on the patient to register the markings (e.g., the coordinate system provided by markings  26  or  36 ) with the patient. The patient can be appropriately anesthetized to perform the insertion procedure. 
     At step  114 , the guidance pad can be attached to the patient. Step  114  can be optional. The guidance pad can be attached by adhesive backing provided on the guidance pad, such as for disposable pads, or an adhesive liquid applied to the back of the guidance pad, such as for reusable guidance pads. In examples using ultrasound, the gel can be applied to the back of the guidance pad to facilitate receiving ultrasound signals. In an example, the adhesive liquid can be an ultrasound gel. 
     At step  116 , the tip of the instrument can be placed at the registration point. As mentioned, ports  24 ,  38  and  76  can act as registration points. Placement of the tip of the instrument at the registration point can register the instrument with the patient and the coordinate system of the surgical plan. However, other registration points on the guidance pad could be used. 
     At step  118 , the tip of the instrument can be placed at an opening in the guidance pad in preparation for insertion into the patient. 
     At step  120 , guidance indicia can be displayed on the guidance pad. As discussed, the guidance indicia can provide visual information relating to the location of the insertion instrument and the anatomy of the patient, as well as information relating to the surgical plan, such as the desired final orientation of the insertion instrument. 
     At step  122 , the insertion instrument can be oriented according to the guidance indicia provided on the guidance pad. For example, the axis of the insertion instrument can be aligned along an axis shown in the guidance pad. 
     At step  124 , the guidance information can be updated to show the location of the guidance instrument and to present updated placement instructions, if needed. 
     At step  126 , the insertion instrument can be further guided into the patient according to the updated guidance information. 
     Steps  120  through  126  can be repeated as necessary to move the insertion instrument to the desired location. 
     At step  128 , the top of the insertion instrument can reach the desired location, such as at the target anatomy where the surgical procedure is to be carried out. 
     At step  130 , the surgical procedure can be carried out. For example, a guide wire can be placed through the insertion instrument and the insertion instrument can be removed. Subsequently, dilators can be placed through the access portal using the guide wire until the incision reaches a desired diameter for receiving a laparoscope tube. At which point, the surgical procedure can take place, such as by using an ablation device or fragmentation device to treat cancerous tissue or kidney stones. 
     At step  132 , instruments used in placing the access portal, e.g, the guidance pad and the insertion needle, can be cleaned and sterilized for subsequent reuse, if configured as reusable devices. 
     The benefits of the systems and methods of the present disclosure can be in the form of, for example, 1) reduced time between access instrument placement and performance of the surgical procedure using the portal (incision) provided by the access instrument, 2) reduced reliance on interventional radiologists, 3) reducing the need for a second access portal to reach other areas of the patient&#39;s anatomy, 4) increased accuracy of access portal placement, 5) reducing the need for a second access portal for improperly placed first access portals, and 6) reduced reliance on real-time imaging systems during the access portal placement. 
     Various Examples and Notes 
     Example 1 is a guidance system for performing a percutaneous access incision, the guidance system comprising: an access needle comprising: a shaft; and a tip located at a distal end of the shaft; and a guidance pad comprising: a dermal side; an outward side; an opening to receive the access needle, the opening extending between the dermal side and the outward side; and a feedback device viewable from the outward side to provide an indication of a depth of the tip beneath the guidance pad and a trajectory of the shaft from the opening. 
     In Example 2, the subject matter of Example 1 optionally includes wherein the feedback device comprises: an arrangement of light emitters surrounding the opening. 
     In Example 3, the subject matter of Example 2 optionally includes wherein each of the light emitters of the array comprises a light emitting diode. 
     In Example 4, the subject matter of any one or more of Examples 2-3 optionally include wherein the light emitters of the array are laid out over a pattern having regular intervals. 
     In Example 5, the subject matter of Example 4 optionally includes wherein the regular intervals correspond to discrete lengths that the tip is located laterally from the opening. 
     In Example 6, the subject matter of any one or more of Examples 2-5 optionally include wherein each of the light emitters of the array has a variable brightness, wherein a brightness of each light emitter is configured to correspond to a distance of the tip below the guidance pad. 
     In Example 7, the subject matter of any one or more of Examples 2-6 optionally include wherein a plurality of the light emitters of the array has a variable color, wherein a color of each light emitter is configured to correspond to a distance of the tip below the guidance pad. 
     In Example 8, the subject matter of any one or more of Examples 1-7 optionally include wherein: the tip comprises a magnetic element; and each of the light emitters of the array includes a magnetic sensor. 
     In Example 9, the subject matter of any one or more of Examples 1-8 optionally include a controller integrated into the guidance pad, the controller configured to activate the feedback device to provide a visual indication of the depth of the tip and the trajectory of the shaft. 
     In Example 10, the subject matter of Example 9 optionally includes wherein the access needle comprises a proximity sensor readable by the controller. 
     In Example 11, the subject matter of any one or more of Examples 9-10 optionally include wherein the feedback device is configured to provide a representation of anatomy of a patient below the guidance pad. 
     In Example 12, the subject matter of Example 11 optionally includes wherein the feedback device is configured to provide a no-go zone in the representations of the anatomy of the patient below the guidance pad. 
     In Example 13, the subject matter of any one or more of Examples 11-12 optionally include wherein the feedback device comprises: a display screen surrounding the opening, wherein the controller is configured to operate the display screen to provide a visual indication of the depth of the tip and the trajectory of the shaft. 
     In Example 14, the subject matter of any one or more of Examples 9-13 optionally include wherein the access needle further comprises an ultrasound transducer in communication with the controller and configured to provide anatomic information to the feedback device. 
     Example 15 is a method for planning guidance of an access needle into a patient in preparation for a minimally invasive surgical procedure, the method comprising: determining a location for an access point on the patient; positioning a guidance pad over the access point; inserting a tip of the access needle through the pad; and displaying guidance information on the guidance pad. 
     In Example 16, the subject matter of Example 15 optionally includes wherein determining the location for the access point on the patient comprises plotting a trajectory for the access needle on imaging of the patient. 
     In Example 17, the subject matter of any one or more of Examples 15-16 optionally include wherein positioning the guidance pad over the access point comprises adhering the guidance pad to the patient. 
     In Example 18, the subject matter of any one or more of Examples 15-17 optionally include wherein inserting the tip of the access needle through the pad comprises: inserting the tip through an opening in the pad that surrounds the access point; and guiding the access needle into the patient according to the guidance information. 
     In Example 19, the subject matter of any one or more of Examples 15-18 optionally include wherein displaying guidance information on the guidance pad comprises displaying an indication of a depth of the tip beneath the guidance pad and a trajectory of the shaft from the access point. 
     In Example 20, the subject matter of Example 19 optionally includes wherein displaying the indication of the depth and the trajectory comprises: varying a color of individual light emitters of an array of light emitters of the guidance pad in response to movement of the tip below the pad, wherein the color of each light emitter is configured to correspond to a distance of the tip below the guidance pad. 
     In Example 21, the subject matter of any one or more of Examples 19-20 optionally include wherein displaying the indication of the depth and the trajectory comprises: varying a light intensity of individual light emitters of an array of light emitters of the guidance pad in response to movement of the tip below the pad, wherein the light intensity of each light emitter is configured to correspond to a distance of the tip below the guidance pad. 
     In Example 22, the subject matter of any one or more of Examples 19-21 optionally include wherein displaying the indication of the depth and the trajectory comprises: showing images on a display screen of the guidance pad corresponding to an orientation of the access needle. 
     In Example 23, the subject matter of Example 22 optionally includes emitting ultrasound signals from the access needle to generate anatomic information for display on the display screen. 
     In Example 24, the subject matter of any one or more of Examples 15-23 optionally include wherein displaying guidance information on the guidance pad comprises displaying anatomy of the patient relative to the guidance pad. 
     In Example 25, the subject matter of Example 24 optionally includes wherein displaying guidance information on the guidance pad comprises displaying no-go zones in the anatomy on the guidance pad. 
     Example 26 is a guidance pad for guiding an access needle into a patient in preparation for a minimally invasive surgical procedure, the guidance pad comprising: a dermal side; an outward side; an opening to receive the access needle, the opening extending between the dermal side and the outward side; and an array of light emitters surrounding the opening and viewable from the outward side to provide an indication of a depth of a tip of the access needle beneath the guidance pad and a trajectory of a shaft of the access needle from the opening, wherein each of the light emitters of the array has a variable property. 
     In Example 27, the subject matter of Example 26 optionally includes wherein the variable property comprises color or light intensity. 
     In Example 28, the subject matter of any one or more of Examples 26-27 optionally include wherein the variable property of each light emitter is configured to change according to a distance a magnetic object of the access needle is from the dermal side. 
     In Example 29, the subject matter of Example 28 optionally includes a magnetic field sensor associated with each of the light emitters of the array. 
     In Example 30, the subject matter of any one or more of Examples 26-29 optionally include a controller integrated into the guidance pad, the controller configured to: activate a first subset of the light emitters to provide a visual indication of no-go zones in anatomy of the patient; and activate a second subset of the light emitters to provide a visual indication of the depth of the tip and the trajectory of the shaft. 
     Each of these non-limiting examples can stand on its own, or can be combined in various permutations or combinations with one or more of the other examples. 
     The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventor also contemplates examples in which only those elements shown or described are provided. Moreover, the present inventor also contemplates examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein. 
     In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
     The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.