Abstract:
A guide for elongate medical instruments includes a pair of cooperating members movable with respect to each other, each member having a receiving channel configured and dimensioned to receive one of said elongate medical instruments, wherein the receiving channels are parallel to one another. Each member may have a clamping surface coupled thereto for retaining the one of said elongate medical instruments in the receiving channel. Indicia may be provided for indicating separation distance between the receiving channels of the members. Methods of guiding elongate medical instruments into a patient also are disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The benefits of Provisional Application No. 60/532,554 filed Dec. 29, 2003 and Provisional Application No. 60/631,086 filed Nov. 24, 2004 are claimed under 35 U.S.C. § 119(e), and the entire contents of these applications are expressly incorporated herein by reference thereto. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to a template grid needle/instrument guide and method for minimally invasive procedures.  
       BACKGROUND OF THE INVENTION  
       [0003]     Most so-called minimally invasive surgical procedures, such as biopsy, high dose rate (HDR) radiation, cryo-ablation, radio frequency (RF) ablation or drainage, are dependent on accurate initial needle or instrument placement into a mass lesion within the body. This critical initial placement typically is done using ultrasound, computed axial tomography (CT) or magnetic resonance imaging (MR) for guidance and confirmation of accurate positioning. For many procedures, placement of more than one needle or instrument is required for effective treatment. Depending on the treatment modality, it is frequently desirable to place additional needles or instruments in a spaced array surrounding the initial one, and in this manner to achieve a consistent spacing/positioning of needles or instruments within and/or around the lesion being treated. The ideal spacing of the instruments that deliver the therapy varies with the treatment modality and the tissue being treated and many details in this area are still under development. However, in every instance a predictable spacing is most desirable.  
         [0004]     Currently almost all such procedures are done using a free-hand technique. With this approach, after placement of the initial needle or instrument, multiple additional passes with subsequent instruments and frequent or continuous real time imaging is used to achieve satisfactory spacing/positioning. In some cases, such as HDR brachytherapy of the prostate or cryotherapy of the prostate, a template grid that is initially rigidly fixed to an external device has been used to achieve accurate spacing and positioning of the treatment instruments. With this method the template is always held firm by an external device until all the instruments are in place.  
         [0005]     There remains a need for a template grid needle/instrument guide and method for minimally invasive procedures that does not rely on externally placed devices to maintain a fixed position.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention relates to a guide for elongate medical instruments that includes a pair of cooperating members movable with respect to each other, each member having a receiving channel configured and dimensioned to receive one of said elongate medical instruments, wherein the receiving channels are parallel to one another. Each member may have a clamping surface coupled thereto for retaining the one of said elongate medical instruments in the receiving channel. Indicia may be provided for indicating separation distance between the receiving channels of the members.  
         [0007]     The pair of cooperating members may be slidable with respect to each other, and each of the cooperating members may have a slot that receives a portion of the other cooperating member. In some embodiments, the pair of cooperating members includes (1) a first cooperating member with a slot formed therein and (2) a second cooperating member with a portion configured and dimensioned to be received in the slot. Also, the pair of cooperating members may be selectively lockable with respect to each other to resist relative movement and each clamping surface may be resiliently biased against the member. The indicia may include (1) a scale on a first of the cooperating members and (2) additional indicia on a second of the cooperating members alignable with the scale. The pair of cooperating members may be releasably secured to each other.  
         [0008]     The present invention further relates to a guide for elongate medical instruments that includes a pair of cooperating members, each member including a portion slidably received in a slot in the other member, each member having a receiving channel configured and dimensioned to receive one of said elongate medical instruments and a clamping surface coupled to the member for retaining the one of said elongate medical instruments in the receiving channel. Indicia may be provided for indicating separation distance between portions of the members, and the receiving channels may have a fixed parallel orientation with respect to one another. The pair of cooperating members may be selectively lockable with respect to each other to resist relative movement, and each clamping surface may be resiliently biased against the member. The indicia may include (1) a scale on a first of the cooperating members and (2) additional indicia on a second of the cooperating members alignable with the scale.  
         [0009]     In addition, the invention relates to a method of guiding elongate medical instruments into a patient using a guide comprising a pair of cooperating members that each define a region for receiving one of said instruments, the regions having a fixed parallel orientation with respect to one another, the method including: selectively adjusting the cooperating members so that the regions are disposed at a desired spacing with respect to each other; guiding a first of said instruments into the patient through a first of the regions of the guide; guiding a second of said instruments into the patient through a second of the regions of the guide so that the instruments are inserted into the patient parallel to one another. The method also may include releasably securing the first of said instruments to the guide.  
         [0010]     In some embodiments, the method may further include: selectively readjusting the cooperating members so that the regions are disposed at another desired spacing with respect to each other; retaining one of said first and second of said instruments in one of the regions and guiding a third of said instruments into the patient through the other of the regions so that each of the instruments are inserted into the patient parallel to one another. The instruments all may be disposed in a straight line. In some embodiments, two of said instruments may be disposed equidistant from the other of said instruments. The second and third of said instruments, for example, may be disposed equidistant from the first of said instruments. A plurality of said instruments may be guided into the patient through the guide to be spaced equidistant from one of said instruments and disposed radially with respect to the one of said instruments. The instruments may be cryoprobes or needles.  
         [0011]     Also, the present invention relates to a method of guiding elongate medical instruments into a patient using a guide that has a plurality of openings having a fixed parallel orientation with respect to one another, the method including: guiding a first of said instruments into the patient; placing the guide so that the first of said instruments extends through a first of the openings; guiding a second of said instruments into the patient through a second of the openings so that the instruments are inserted into the patient parallel to one another. In some embodiments, the guide comprises a pair of cooperating members and the method further comprises selectively adjusting the cooperating members so that the openings in the members are disposed at a desired spacing with respect to each other. The guide may be formed of a pair of cooperating members that each define at least one of said openings for receiving one of said instruments. The first of said openings may be a slot extending from a perimeter of the guide, or the first of said openings may be a central hole in the guide. The method may further include: coupling a plug to the first of said instruments; demountably coupling the plug in the first of the openings. In addition, the method may further include: guiding a third of said instruments into the patient through a third of the openings so that the instruments are inserted into the patient parallel to one another.  
         [0012]     In accordance with one method of the present invention, an instrument such as a needle first may be inserted into a patient, and then a guide or grid subsequently may be coupled to the instrument for use in placing additional instruments in the patient. The guide or grid may facilitate placement of multiple instruments in a patient such that the instruments are disposed parallel to one another. In addition, arrays of instruments may be directed into a patient with such a grid or guide, thus for example permitting linear or radial positioning of instruments in a patient to be achieved.  
         [0013]     The present invention further relates to a template grid and method for achieving accurate placement and spacing of needles/instruments that may be advantageous for minimally invasive therapies. Such a template grid may depend on an initially placed needle/instrument and then also may depend on subsequently placed needles or instruments for stability and positioning, rather than having its position held by an external device. In one exemplary embodiment, the template grid may be designed so that the initial needle/instrument may be placed or guided through it prior to initial placement within a lesion, or the template grid may be designed to attach to the initial needle/instrument after initial placement with respect to a lesion. In either case, the subsequent needles/instruments may be placed through the template grid to achieve accurate spacing and positioning in relation to the initially placed needle/instrument. The relative spacing and positioning of all needles/instruments that are placed after the initial one or two may vary as a function of the design of the template grid. The template grid may vary considerably in size, shape and dimension depending on the application. The template grid may or may not remain in place for the duration of a procedure or therapy. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Preferred features of the present invention are disclosed in the accompanying drawings, wherein:  
         [0015]      FIG. 1A  is a top perspective view of a first embodiment of a guide according to the present invention;  
         [0016]      FIG. 1B  is another top perspective view of the guide of  FIG. 1A ;  
         [0017]      FIG. 1C  is a bottom perspective view of the guide of  FIG. 1A ;  
         [0018]      FIG. 1D  is another bottom perspective view of the guide of  FIG. 1A ;  
         [0019]      FIG. 1E  is a front view of the guide of  FIG. 1A ;  
         [0020]      FIG. 1F  is a back view of the guide of  FIG. 1A ;  
         [0021]      FIG. 1G  is a top view of the guide of  FIG. 1A ;  
         [0022]      FIG. 1H  is a bottom view of the guide of  FIG. 1A ;  
         [0023]      FIG. 1I  is a left view of the guide of  FIG. 1A ;  
         [0024]      FIG. 1J  is a right view of the guide of  FIG. 1A ;  
         [0025]      FIG. 2  is a side perspective view of a second embodiment of a guide according to the present invention;  
         [0026]      FIG. 3A  is a top view of a third embodiment of a guide according to the present invention in an unassembled state;  
         [0027]      FIG. 3B  is a top view of the guide of  FIG. 3A  in an assembled state;  
         [0028]      FIG. 4A  is a top view of a fourth embodiment of a guide according to the present invention;  
         [0029]      FIG. 4B  is a side perspective view of the guide of  FIG. 4A  with a split plug for use therewith;  
         [0030]      FIG. 5A  is a top perspective view of a fifth embodiment of a guide according to the present invention; and  
         [0031]      FIG. 5B  is a bottom perspective view of the guide of  FIG. 5A . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]     Terms such as “top,” “bottom,” and “side” as used herein are provided as a non-limiting examples of the orientation of features.  
         [0033]     Referring initially to  FIGS. 1A-1J , a preferred exemplary embodiment of a guide  10  according to the present invention is shown. Guide  10  includes cooperating slide guides  12 ,  14  with clamps  16 ,  18 , respectively, coupled thereto. Thumb screws  20 ,  22  and corresponding washers  24 ,  26  adjustably couple clamps  16 ,  18  to guides  12 ,  14 . In particular, thumb screws  20 ,  22  are threadably received in threaded holes  20   a ,  22   a  in guides  12 ,  14 , respectively. In addition, optionally holes  17   a ,  19   a  may be provided in clamps  16 ,  18  and aligned with corresponding threaded holes  17   b ,  19   b  in slide guides  12 ,  14 . Such additional holes provide a further means for securing clamps  16 ,  18  to slide guides  12 ,  14 , as for example with threaded screws (not shown). Slide guide  12  includes a slot  28  in which an elongate portion  30  of slide guide  14  is slidably received. A slot  32  in elongate portion  30  of slide guide  14  receives a set screw  34  therein which is threadably received in a hole  34   a  in slide guide  12 . Set screw  34  is provided with a corresponding washer  35 . Thus, slide guide  14  is demountably coupled to slide guide  12  with set screw  34 . In addition, slide guide  14  includes a slot  36  in which an elongate portion  38  of slide guide  12  is slidably received. A slot  40  in elongate portion  38  of slide guide  12  receives a thumb screw  42  therein which is mounted on a washer  44  and threadably received in a hole  42   a  in slide guide  14 . Thus, slide guide  12  is demountably coupled to slide guide  14  with thumb screw  42 .  
         [0034]     To assist in adjusting thumb screws  20 ,  22 ,  42 , surface texturing and preferably knurling is provided on the heads thereof. Also, set screw  34  may be provided for example in a Phillips-head configuration to facilitate adjustment of the tightness of coupling slide guide  14  to slide guide  12  such as by using a screw driver. In addition, thumb screws  20 ,  22  for example may be 10-32 aluminum screws, while thumb screw  42  may be an 8-32 aluminum screw.  
         [0035]     Clamps  16 ,  18  preferably are configured, dimensioned and formed of a suitable material to provide resilient biasing against corresponding slide guides  12 ,  14 . In particular, when a surface proximate an end of each clamp  16 ,  18  abuts a slide guide  12 ,  14 , and when thumb screws  20 ,  22  are installed to bear against clamps  16 ,  18 , respectively, the clamps are biased away from slide guides  12 ,  14 .  
         [0036]     Slots  28 ,  36  preferably are substantially parallel to one another, and are sized to accommodate elongate portions  30 ,  38 , respectively. Moreover, elongate portions  30 ,  32  preferably are configured and dimensioned to be guided within slots  28 ,  36 , respectively, and preferably are guided substantially parallel to one another.  
         [0037]     Slide guides  12 ,  14  have elongate grooves  46 ,  48 , respectively, disposed proximate free ends thereof, and clamps  16 ,  18  have elongate protruding edges  50 ,  52  that oppose grooves  46 ,  48  respectively. In the preferred exemplary embodiment, grooves  46 ,  48  are V-shaped, but in alternate embodiments the grooves may have other geometries such as arcuate shapes. Preferably, grooves  46 ,  48  are sized to accommodate linear instruments of a variety of sizes. For example, grooves  46 ,  48  may be sized to receive elongate instruments between 18 gauge and 2.5 mm in diameter. When an elongate instrument abuts a groove  46 ,  48 , the instruments may be releasably secured in the groove by moving clamps  16 ,  18  so that a protruding edge  50 ,  52  abuts the instrument. The position of the clamping surface created by protruding edge  50 ,  52  is adjustable due to thumb screws  20 ,  22 , respectively, which may be operated to bear down on clamps  16 ,  18  to decrease the separation distance between a groove  46 ,  48  and its corresponding clamp  16 ,  18  with edge  50 ,  52 . Preferably, when slide guides  12 ,  14  are coupled to each other as indicated, the respective grooves  46 ,  48  therein are aligned parallel to each other. Thus, linear instruments placed in grooves  46 ,  48  may be disposed parallel to one another.  
         [0038]     By tightening a thumb screw  20 ,  22  while an elongate instrument is disposed in a corresponding groove  46 ,  48 , the instrument may be tightly retained in a given position in the groove. Alternatively, if less pressure is applied by the thumb screw the instrument may be secured within the groove but loosely retained so that movement of the instrument substantially parallel to the groove is freely permitted. This user selectable feature for example permits flexibility in needle/instrument placement during minimally invasive procedures.  
         [0039]     Advantageously, slide guides  12 ,  14  are slidably associated with each other in a predetermined relationship such that a known, predictable spacing may be achieved between grooves  46 ,  48  and thus elongate instruments disposed therein. In particular, a separation distance X between grooves  46 ,  48  may be set by a user. Slide guide  12  includes indicia  54  in the form of a scale, preferably disposed on a side thereof. In one preferred embodiment, slide guide  12  includes a scale for indicating separation distances X between about 3 mm and about 21 mm. As can be seen for example in FIGS.  1 C,  1 D,  1 H, slide guide  14  also may be provided with indicia  56 , preferably in the form of a line or arrow oriented generally perpendicular to slot  32  and alignable with the scale of indicia  54 . Alternatively, indicia  56  may be a dot or other feature, and optionally may be scored on slide guide  14 . As shown for example in  FIG. 1C , indicia  56  is provided on a bottom surface of  14   a  of slide guide  14  so as to be visual to a user when guide  10  is assembled. However, the location of indicia  54 ,  56  as disclosed is preferred but non-limiting. In an alternate embodiment, indicia instead may be provided on one or more of slide guides  12 ,  14 , and may even be provided on a side surface such as surface  14   b  as shown in  FIG. 1E . The indicia is provided for the purpose of indicating a known, predetermined spacing between grooves  46 ,  48 . When set screw  34  and/or thumb screw  42  is loosened to permit sliding of elongate portion  30  of slide guide  14  within slot  28  of slide guide  12 , a user may select a desired separation distance X, for example from about 3 mm to about 21 mm. Set screw  34  and/or thumb screw  42  subsequently may be tightened to releasable fix the position of elongate portion  30  in slot  28  and thus releasably fix the separation distance X. Advantageously, by placing a first elongate instrument such as a needle in a first groove  46 ,  48 , a second elongate instrument may be placed a known or predetermined separation distance X away from the first elongate instrument. And preferably the first and second elongate instruments may be placed parallel to one another. The first elongate instrument serves effectively as the guide for the placement of the second elongate instrument. Instrument placement during minimally invasive procedures thus may proceed in a registered/indexed fashion.  
         [0040]     In addition, this procedure may be repeated for example so that after the second elongate instrument is placed, the clamping action on one of the first and second elongate instruments is released and the other elongate instrument is then used as the guide for placing one or more additional elongate instruments. In particular, the separation distance X may be changed so that another elongate instrument may be placed at yet another separation distance. Alternatively, the same separation distance may be maintained while additional elongate instruments are placed in a radial fashion with respect to one of the first and second elongate instruments.  
         [0041]     Guide  10 , for example, may be hand-held, attached to a guidance device, or held by a mechanical positioning arm to establish the positioning thereof with respect to a patient. Guide  10  permits elongate instruments such as needles to be captured and released as desired to create radial or rectilinear placement arrays.  
         [0042]     A pair of holes  58 ,  60  also may be provided in guide  10  for mounting, as may be desired, to a guidance tool such as a stereotactic guidance device for initial needle placement. In one non-limiting exemplary embodiment, both holes  58 ,  60  are provided in slide guide  14 .  
         [0043]     In the preferred exemplary embodiment, components of guide  10  are formed of aluminum, although some or all components also may be formed of stainless steel. In alternate embodiments, some or all of the components may be formed of polymer.  
         [0044]     Turning to  FIG. 2 , another exemplary embodiment of a template grid  100  according to the present invention is shown. In particular, guide  10  is generally circular with a through slot  102  extending from a perimeter thereof to proximate the center thereof. Holes  104  are provided in a radial fashion about the perimeter. The holes and slot are configured and dimensioned for guiding elongate instruments therein, preferably parallel to one another.  
         [0045]     In another exemplary embodiment of a template grid  110  according to the present invention, shown in  FIGS. 3A-3B , a generally circular guide is provided by two interlocking halves  112 ,  114 . A pair of pegs  116   a ,  116   b  are received in corresponding grooves  118   a ,  118   b , respectively. A central hole  120  is formed by the two opposing halves. Additional radially disposed holes  122  also are provided. The holes are configured and dimensioned for guiding elongate instruments therein, preferably parallel to one another.  
         [0046]     In yet another embodiment of a template grid  130  according to the present invention as shown in  FIGS. 4A-4B , a circular guide is provided with a central hole  132  and radially disposed holes  134 . A split plug  136  also is provided with a slot for engaging a centrally disposed instrument and for mounting in central hole  132 . The holes and slot are configured and dimensioned for guiding elongate instruments therein, preferably parallel to one another.  
         [0047]     In addition, another exemplary embodiment of a template grid  140  is shown in  FIGS. 5A-5B . A central needle is coupled to one side of a circular guide, and through-holes for receiving additional instruments are radially disposed with respect thereto. The holes are configured and dimensioned for guiding elongate instruments therein, preferably parallel to one another.  
         [0048]     In an exemplary application of the template grids and methods of the present invention, a four centimeter renal tumor is treated using for example a template grid of  FIGS. 2-5 . A tumor of such size is too large to be treated with a single cryoprobe and may require as many as six or more probes for complete treatment. To achieve uniform freezing, it is desirable to have the probes accurately spaced and running parallel to each other and to place temperature sensors at strategic locations around the tumor. A guide, possibly with a particular thickness, and with appropriate hole spacing, is attached to an initial probe after placement thus allowing for rapid and accurate subsequent placement of multiple parallel probes and surrounding sensors.  
         [0049]     Prior art template grids for needle/instrument placement are used following initial positioning and stabilization by an external device. However, in some embodiments of the present invention, the template grid is positioned and stabilized by the needle(s)/instrument(s) placed into the patient. The mechanical means to accomplish this type of template grid and method of use, as shown for example in  FIGS. 2-5 , include but are not limited to: (1) a slot that may engage an initially placed needle/instrument, (2) a multipart template grid that comes together to engage an initially placed needle/instrument, (3) a template grid configured to fit over or around an initially placed needle/instrument, (4) a template grid designed to have the needle/instrument passed through it prior to initial placement, and (5) a template grid with a needle/instrument attached to it.  
         [0050]     All template grids and guides used in invasive applications must be sterile or else not come in direct or indirect contact with the patient. Since these grids and guides by design will come in direct or indirect contact via the needle/instrument or by resting on the surface of the body or an organ in open surgery, they must be sterilizable and preferably be available to the user pre-sterilized and disposable.  
         [0051]     While various descriptions of the present invention are described above, it should be understood that the various features can be used singly or in any combination thereof. Therefore, this invention is not to be limited to only the specifically preferred embodiments depicted herein.  
         [0052]     Further, it should be understood that variations and modifications within the spirit and scope of the invention may occur to those skilled in the art to which the invention pertains. For example, the clamping surfaces of clamps  16 ,  18  may be spring-loaded or otherwise resiliently biased away from slide guides  12 ,  14 . Also, slide guides  12 ,  14  instead may be coupled to each other with only one elongate portion received in one slot. Each slide guide  12 ,  14  may be provided with more than one groove for receiving elongate instruments such as needles; for example, three grooves may be provided proximate a free end of the slide guide. At least one of the slide guides may be received in an enclosed slot extending within the other slide guide, rather than in an open slot as discussed with respect to guide  10 . Further, a ratchet arrangement may be provided such that movement of slide guides  12 ,  14  with respect to each other is indexed. Accordingly, all expedient modifications readily attainable by one versed in the art from the disclosure set forth herein that are within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is accordingly defined as set forth in the appended claims.