Patent Publication Number: US-2006009787-A1

Title: Simplified stereotaxtic brain surgery device, and band used for determining position at which such device is mounted on patient head

Description:
TECHNICAL FIELD  
      The present invention relates to simplified stereotactic brain surgery devices used for surgery on cerebral diseases such as hypertensive cerebral hemorrhages, brain tumors, brain abscesses, hydrocephalus, or cerebral cysts, and to bands used for determining the position at which such a device is mounted on a patient&#39;s head.  
     BACKGROUND ART  
      Conventionally, so-called Komai-type CT stereotactic brain surgery devices (referred to as “Komai-type devices” in the following) are known as stereotactic brain surgery devices (see Document 1 below, for example). The Komai-type devices had hygienic problem, because it is necessary to mount the device from the stage of taking the CT images prior to surgery.  
      Document 1: Hiroshi Abe, Ryuichi Tanaka, Kimiyoshi Hayakawa, Haruhiko Kikuchi, Takashi Tsubokawa, Satoru Matsumoto (ed.) “NOUSHINKEIGEKASHIKKAN-NO SHUJUTSU TO TEKIOU II” (“Surgery of Neurosurgical Diseases and its Application II”), Asakura Shoten, Oct. 15, 1990, First Ed., pp. 237-245.  
      Furthermore, the following Document 2 proposes a simplified stereotactic brain surgery device with a simpler configuration. This device requires for example an arc-shaped frame for the puncturing with a puncturing needle from the desired direction, which made its configuration complex. Furthermore, there were also disadvantages with regard to safety.  
      Document 2: JP H11-137568A (Published on May 25, 1999, in particular  FIG. 1 )  
     DISCLOSURE OF THE INVENTION  
      It is an object of the present invention to provide a simplified stereotactic brain surgery device that can be manufactured easily and inexpensively, and that is hygienic with superior handling properties and safety, and moreover to provide a band that is used to determine the position where this device is mounted to a patient&#39;s head.  
      In order to achieve these objects, a simplified stereotactic brain surgery device according to the present invention comprises a guide frame for guiding a puncturing needle&#39;s tip to a predetermined location within a brain; and left and right fixing frames, each having a fixing member for fixing the device to the patient&#39;s head, the fixing frames being displaceable in a longitudinal direction of the guide frame; wherein the guide frame is provided with a plurality of guide depressions that guide the puncturing needle&#39;s tip to a point on the line connecting the left and right fixing members.  
      With this configuration, the guide depression that is used to guide the puncturing needle to a predetermined location within the brain (location of the lesion) can be selected from the plurality of guide depressions, so that the puncturing needle can be inserted from the optimum direction into the brain, and after first inserting a puncturing needle with a smaller diameter along the selected guide depression, a puncturing needle with a larger diameter can be inserted along the same guide depression, so that brain surgery with a higher degree of safety becomes possible. Furthermore, it is also possible to simultaneously insert a plurality of puncturing needles from different guide depressions.  
      It should be noted that here, “puncturing needle” refers to a structure having an outer cylinder and an inner cylinder, and with which drainage or evacuation can be performed from the tip, in an emptied state that is achieved by pulling out the inner cylinder. “Puncturing needle” includes a probe, for example.  
      It is preferable that the simplified stereotactic brain surgery device according to the present invention further comprises any of the following configurations.  
      (1) A configuration wherein the guide frame is provided with a scale. Thus, it is easy to position the left and right fixing frames, and to specify the position of the selected guiding depression, for example.  
      (2) A configuration wherein the guide frame comprises a displacement prevention member for preventing displacement of the puncturing needle when the puncturing needle is guided by one of the guide depressions. Thus, when a puncturing needle is inserted into the brain, a displacement of the puncturing needle can be reliably prevented, so that a device with high safety can be realized.  
      (3) The configuration of (2), further comprising a pressing member that presses the displacement prevention member against a main member of the guide frame. Thus, a displacement of the puncturing needle can be more reliably prevented.  
      (4) A configuration wherein an auxiliary fixing member for aiding fixation of the device on the patient&#39;s head is provided on at least one of the left and right fixing frames. Thus, the device can be reliably fixed to the patient&#39;s head.  
      (5) The configuration of (2), wherein the auxiliary fixing member comprises an auxiliary fixing portion for aiding fixation of the device on the patient&#39;s head, a linking member linking the auxiliary fixing portion and the fixing frame at an adjustable angle with the fixing member at the center, and a distance adjustment member for adjusting a distance between the auxiliary fixing portion and that fixing member. Thus, the position where the device is fixed to the patient&#39;s head with the auxiliary fixing member can be freely selected within the adjustment range. That is to say, the range over which fixing with the auxiliary fixing member is possible is broad, and a safer fixing position can be selected.  
      In accordance with the present invention, a band that is used prior to brain surgery using the simplified stereotactic brain surgery device according to the present invention, to determine a position where the device is mounted to the patient&#39;s head and to mark this position, has a plurality of marker members that are arranged at opposing positions when the band is wrapped around the patient&#39;s head. It is preferable that the marker members comprise aluminum or an alloy thereof, stainless steel, brass, copper, nichromium, processed animal bone, or tooth. If the marker members are made from any of these materials, then the positions of the marker members when taking a CT or the like can be clearly visible in the form of dots, and it is possible to easily work for determining the device mounting position on the patient&#39;s head.  
      It is preferable that the main member of the band is mesh-shaped. Thus, it is possible to write marks from above the band onto the patient&#39;s head around which the band is wrapped.  
      These and other objects, features and advantages of the present invention will become more apparent from the following description. Also, beneficial results of the present invention should be obvious from the following description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded perspective view showing the overall configuration of a simplified stereotactic brain surgery device according to an embodiment of the present invention.  
       FIG. 2  shows a front view and a side view of this simplified stereotactic brain surgery device in an assembled state.  
       FIG. 3  is an enlarged view of this simplified stereotactic brain surgery device showing how a puncturing needle is inserted between a main member of a frame with puncture guides and a displacement prevention plate.  
      FIGS.  4 ( a ) to 4( d ) show front views and rear views of the two bands constituting a marking band according to an embodiment of the present invention.  
       FIG. 5  is a diagram showing the configuration of a marking band.  
      FIGS.  6 ( a ) to  6 ( c ) illustrate a step of applying markings to the patient&#39;s head prior to the operation, using this marking band.  
      FIGS.  7 ( a ) and  7 ( b ) illustrate a step of applying markings to the patient&#39;s head prior to the operation, using this marking band.  
      FIGS.  8 ( a ) and  8 ( b ) are diagrammatic views of CT images and illustrate a step of determining the device mounting position.  
      FIGS.  9 ( a ) and  9 ( b ) illustrate a step of applying markings to the patient&#39;s head prior to the operation, using this marking band.  
      FIGS.  10 ( a ) and  10 ( b ) are diagrammatic views of CT images and illustrate a step of determining the distance between the left and right device mounting positions and the center of the lesion.  
      FIGS.  11 ( a ) and ( b ) are diagrams showing the operating field.  
       FIG. 12  is a diagram illustrating the step of setting the position of the left fixing frame of the simplified stereotactic brain surgery device  
       FIG. 13  is a diagram illustrating a step of mounting the simplified stereotactic brain surgery device to the patient&#39;s head.  
       FIG. 14  is a diagram illustrating a step of selecting the optimum guide groove before inserting the puncturing needle from the perforation location into the brain.  
       FIG. 15  is a diagram showing the state in which the simplified stereotactic brain surgery device is fixed, with the auxiliary fixing support, in the position that is optimal for puncturing  
       FIG. 16  is a diagram showing a stopper and how this stopper is attached to a puncturing needle.  
       FIG. 17  is an exploded perspective view showing the overall configuration of a simplified stereotactic brain surgery device in accordance with another embodiment of the present invention. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION  
      The following is an explanation of an embodiment of the present invention, with reference to FIGS.  1  to  17 .  
      (1) Device Configuration of the Present Embodiment  
       FIG. 1  is an exploded perspective view showing the overall configuration of a simplified stereotactic brain surgery device (also referred to as “the device” in the following) according to the present embodiment.  FIG. 2  shows a front view and a side view of the device in an assembled state (also shown are two puncturing needles  71  and  72  with different diameters). The device  1  includes a frame  2  with puncture guides (guide frame), a right fixing frame  3 , a left fixing frame  4 , and an auxiliary fixing support (auxiliary fixing member)  5 .  
      A plurality of guide grooves  21  (guide depressions) for guiding tips  71   a  and  72   a  of the puncturing needles  71  and  72  to the location of the lesion within the brain (in the later-described usage method, the hematoma corresponds to this lesion location) and scales (scale marks)  22  that are used, for example, for positioning the left and right fixing frames  3  and  4  are engraved in the frame  2  with puncture guides. The scales  22  have a point of origin “0” in their center, and a set of marks with 5 mm intervals to the left and right until 11 cm on the left and right.  
      The guide grooves  21  are provided in the same number as the scales  22 , and of these, the guide groove  210  that is located at the point of origin “0” is engraved in a direction B perpendicular to an arrow direction A, which is a longitudinal direction of the frame  2  with puncture guides (in other words, the direction B is perpendicular to a line L connecting later-described left and right fixing needles  31  and  41 ). The directions of the guide grooves  21  other than this guide groove  210  are all engraved in a direction pointing to an intersection point P at which a line X extending from the groove direction of the guide groove  210  intersects with the line L connecting the left and right fixing needles  31  and  41 . That is to say, all of the guide grooves  21  on the frame  2  with puncture guides are formed in a radiating pattern with the intersection point P at the center, such that lines extending from groove directions converge at the intersection point P.  
      On a surface  2   a  onto which the guide grooves  21  and the scales  22  are engraved, the frame  2  with puncture guides has a displacement prevention plate (displacement prevention member)  23  for preventing displacement when inserting the puncturing needles  71 ,  72 . The displacement prevention plate  23  is formed transparently, so that the guide grooves  21  and the scales  22  can be viewed through this displacement prevention plate  23 . The displacement prevention plate  23  is attached to the main member  25  of the frame  2  with puncture guides by screws  242  that are screwed into left and right screw holes  241 , coil springs  243  (pressure members), and washers  244 . Thus, there is a gap of the thickness of the washer  244  between the displacement prevention plate  23  and the main member  25 , and the displacement prevention plate  23  is pressed against the main member  25  of the frame  2  with puncture guides by the spring force of the coil spring  243 . Consequently, even when either of the two puncturing needles  71  and  72  of different diameters is inserted between the main member  25  and the displacement prevention plate  23 , the puncturing needle  71  or  72  is gripped tight, and its displacement can be prevented securely.  
       FIG. 3  is an enlarged view showing how the puncturing needle  71  is inserted between the main member  25  of the frame  2  with puncture guides and the displacement prevention plate  23 . As shown in the figure, the puncturing needle  71  is sandwiched by the main member  25  and the displacement prevention plate  23 , and is securely inserted along one of the guide grooves  21 . Consequently, displacement of the puncturing needle  71  during insertion can be prevented, and the tip  71   a  of the puncturing needle  71  can reach the lesion location in the brain securely. It should be noted that in  FIG. 3 , the scales  22  have been omitted to keep the explanations simple.  
      Referring again to  FIG. 1  and  FIG. 2 , one end  26  and the other end  27  of the frame  2  with puncture guides are tapered (that is, widening from a front surface  2   a  to a rear surface  2   b ) and the main member  25  of the frame  2  with puncture guides is provided with a substantially trapezoidal cross section. Depressions  32  and  42 , into which this trapezoid shape can be fitted, are formed in the left and right fixing frames  3  and  4 . Consequently, the fixing frames  3  and  4  are configured such that they are freely shiftable in the longitudinal direction of the frame  2  with puncture guides (that is, in the direction of arrow A), by fitting the main member  25  of the frame  2  with puncture guides into the depressions  32  and  42  of the fixing frames  3  and  4  and sliding.  
      When the left and right fixing frames  3  and  4  are to be fixed in a given position on the frame  2  with puncture guides, they can be easily fixed by tightening the fixing screws  34  and  44  from rear sides  33  and  43  of the fixing frames  3  and  4  at that position. That is to say, the fixing frames  3  and  4  can be easily fixed at that position by passing the fixing screws  34  and  44  through screw holes  35  and  45  of the fixing frames  3  and  4  and tightening the fixing screws  34  and  44  against the rear side  2   b  of the frame  2  with puncture guides.  
      As shown in  FIG. 1 , the depressions  32  and  42  of the left and right fixing frames  3  and  4  are further provided with substantially rectangular depressions  38  and  48  (which are depressions and do not reach through to the rear sides  33  and  43 ), and slide-stopping members  39  and  49  are fitted into these rectangular depressions  38  and  48 . The slide-stopping members  39  and  49  have a substantially planar shape, but are slightly tilted from the left and right toward the center, and they are formed such that when they are fitted into the rectangular depressions  38  and  48 , the center of the slide-stopping members  39  and  49  protrudes slightly from the surface of the depressions  32  and  42 . Thus, once the fixing frames  3  and  4  have been fixed to the frame  2  with puncture guides, easy shifting of the fixing frames  3  and  4  is prevented, and even if the fixing screws  34  and  44  are loosened, easy positional displacement of the fixing frames  3  and  4  can be prevented.  
      The left and right fixing frames  3  and  4  have fixing needles (fixing members)  31  and  41  at their ends. The fixing needles  31  and  41  are for mounting the device  1  to the patient&#39;s head, and are fixed to the patient&#39;s cranium at a later-described device mounting location Cr, Cl (see  FIG. 14 ).  
      A male thread  37  is formed on the right fixing frame  3  on the side opposite to the fixing needle  31 , and an auxiliary fixing support  5  can be attached to the right fixing frame  3  through this male thread  37 . The auxiliary fixing support  5  is for assisting the mounting of the device  1  to the patient&#39;s cranium by three-point fixing (see  FIG. 15 ). The auxiliary fixing support  5  includes an auxiliary fixing needle (auxiliary fixing portion)  51 , a linking arm (linking member)  52 , and a position fixing knob  53 . The auxiliary fixing needle  51  has a threaded portion  511  and a knob portion  512 . The threaded portion  511  is screwed into a screw hole  521  of the linking arm  52 . Consequently, by rotating the knob portion  512 , the tip  51   a  of the auxiliary fixing needle  51  can be shifted in the direction of arrow C (which is a direction parallel to the direction of arrow A).  
      One end of the linking arm  52  is provided with an oblong aperture portion  522  in longitudinal direction of the linking arm  52 . The linking arm  52  is fixed to the right fixing frame  3  by turning and fastening the position fixing knob  53 , which is screwed onto the male thread  37 , while the male thread  37  is inserted with play into this aperture portion  522 . Thus, when the position fixing knob  53  is loosened, the angle θ between the linking arm  52  and the right fixing frame  3  and the distance E between the fixing needle  31  and the auxiliary fixing needle  51  can be easily adjusted by fastening the position fixing knob  53  after setting the angle θ and the distance E as desired. That is to say, the position fixing knob  53  and the aperture portion  522  have the role of an adjusting portion for adjusting the angle θ and the distance E.  
      Scalp surface matching lines  36  and  46  are engraved into the left and right fixing frames  3  and  4 . These scalp surface matching lines  36  and  46  are used to set the positions of the fixing frames  3  and  4  by adjusting them to scalp surface positions of the device mounting locations Cr and Cl. How these scalp surface matching lines  36  and  46  are used specifically is explained in more detail later.  
      The main member  25 , the left and right fixing frames  3  and  4  and the auxiliary fixing support  5  of the device  1  are all made of stainless steel. The displacement prevention plate  23  is transparent, so that it is made of acrylic resin.  
      (2) Configuration of the Band of the Present Embodiment  
      The following is an explanation of a marking band  6  for determining the mounting position of the device  1  on the patient&#39;s head, and for marking this position, prior to brain surgery using the device  1 . As shown in  FIG. 4  and  FIG. 5 , this marking band  6  is made of a combination of two bands  61  and  62 , and is wrapped as a ring-shaped band around the patient&#39;s head by linking the respective ends of these two bands  61  and  62  together with cloth tapes  63  and  64  (see  FIG. 6 ( c )). The cloth tapes  63  and  64  are Velcro™ type tapes, and can engage one another in a releasable manner. The cloth tapes  63  and  64  are sewn onto a main member  65  of the two bands  61  and  62 . The cloth tape  63  is formed on an oblong fashion along the main member  65 , such that the length of the ring formed by the marking band  6  can be easily adjusted to the size of the patient&#39;s head. Furthermore, a strengthening fabric  66  is sewn onto the reverse side of the main member  65  onto which the cloth tape  63  is sewn, in order to strengthen the marking band  6  and prevent it from slipping.  
      The two bands  61  and  62  are provided with six mark sticks (marker members)  67  at equal intervals. These mark sticks  67  are used in order to determine the mounting location of the device  1  on the patient&#39;s head using CT or the like. How these mark sticks  67  are used specifically is explained in more detail later. The marking band  6  is wrapped around the patient&#39;s head such that the six mark sticks  67  provided on the two bands  61  and  62  are located at positions in opposition to one another. The length of the mark sticks  67  is about 5 cm, and they are made of metal rods from an aluminum alloy having flexibility. By using such a material, the positions of the mark sticks  67  appear as clear dots on the photograph when taking a CT or the like (see FIGS.  8 ( a ) and  8 ( b )).  
      The main members of two bands  61  and  62  are formed as a mesh, so that when wrapped around the patient&#39;s head, markings can be applied to the patient&#39;s head (marks can be written) from above the marking band  6 . Moreover, a central portion  68  of the two bands  61  and  62  is made of a double-layered mesh material, in order to provide the marking band  6  with a given strength, and so that the mark sticks  67  can be easily inserted into the main members  65 . In view of its strength, this mesh material is not made of a natural fiber, but of a synthetic fiber.  
      (3) Method for Using the Device and the Band of the Present Embodiment  
      The following is an explanation of an example of a method for using the device  1  and the marking band  6 , divided into the marking stage prior to the operation and the operation stage of evacuation surgery of a cerebral hematoma.  
      A. The Marking Stage Prior to the Operation  
      [Step A- 1 ] Which slice has the maximum diameter of the cerebral hematoma is known from the cerebral CT that was previously taken for diagnosis (or taken for pre-surgery evaluation). It is read and confirmed how many centimeters this slice is above (or below) the OM line (the line extending from the eyeball to the external auditory canal). This value is taken as X cm (see  FIG. 6 ( a ) and ( b )).  
      [Step A- 2 ] The OM line is determined on the patient&#39;s head (which must be completely shaved) and marked. The line at X cm above (or below) and parallel to this OM line is also marked (referred to as “line X”) (see  FIG. 6 ( a ) and ( b )). This line X does not necessarily have to be drawn with great accuracy on the head, because the mark sticks  67  of the marking band  6  cover a total vertical length of 5 cm.  
      [Step A- 3 ] The marking band  6  is stored with the two bands  61  and  62  still separate, and the mark sticks  67  not inserted. Accordingly, first, the mark sticks  67  are inserted into the two bands  61  and  62 , and then the marking band  6  is wrapped around the patient&#39;s head with the line X at the center, as shown in  FIG. 6 ( c ).  
      [Step A- 4 ] The patient is moved to the CT room, and the patient&#39;s head is fixed inside the CT gantry. At this time, care is taken that the marking band  6  is not hidden by a band installed on the CT gantry, so that the patient&#39;s head can be irradiated with a beam in the following Step A- 7 .  
      [Step A- 5 ] CT images are taken.  
      [Step A- 6 ] After taking the CT, the slice in which the hematoma is shown largest (this is also referred to as the target slice or “T slice” below) is displayed on the CT monitor.  
      [Step A- 7 ] A beam matching that of the T slice (for example the tenth slice) is irradiated onto the patient&#39;s head from the CT gantry by a radiological technician or the like, and the line on which the beam is incident (referred to as the line T) is marked on the head from above the marking band  6  with a magic marker or the like. As noted above, the marking band  6  is made of a mesh, so that ink of the magic marker or the like can easily penetrate to the head (see  FIG. 7 ( a ) and ( b )).  
      [Step A- 8 ] Six points (referred to as plots)  8  as shown in  FIG. 8 ( a ) are marked as markings in the T slice on the monitor, on both sides of the cerebral section. These plots  8  represent the cross sections of the mark sticks  67  and the position of each plot  8  accurately reflects the position of a mark stick  67 . Accordingly, from among the combinations of straight lines connecting the left and right plots  8  that run through the center of the hematoma H, the combination is selected, that is most stable and for which there are no obstructions directly near the plots  8 , when the device is mounted. Thus, the selected plots  8  are for example plot “a” on the right side and plot “b” on the left side, which are referred to as Ra and Lb, respectively (see  FIG. 8 ( b )).  
      [Step A- 9 ] The numbers of the left and right mark sticks  67  corresponding to the selected plots  8  as counted from the front are noted down, for example as (R, L)=(3, 4). After this, the positions of the mark sticks  67  corresponding to the selected plots  8  are immediately marked by magic marker or the like on the patient&#39;s head. The intersections (Cr, Cl) of the line of the T slice marked in Step A- 7  and these mark sticks  67  serve as the mounting location of the device  1  (see  FIG. 9 ( a ) and ( b )).  
      [Step A- 10 ] When the marking on the patient is finished, a measurement is performed deliberately on the CT monitor. In this measurement, a line is drawn between Ra and Lb, and the distance to the center of the hematoma (referred to as Hc) (the distance Ra-Hc in the case of a hematoma on the right, and the distance Lb-Hc in the case of a hematoma on the left) is measured and recorded (see  FIG. 10 ( a ) and ( b )). Each distance can be determined by a computer calculation on the monitor.  
      When the distances Ra-Lb, Ra-Hc and Lb-Hc have been thus determined, adjustment in accordance with the determined distances is possible without tightening or loosening the fixing frames  3  and  4  when mounting the device  1 . Thus, the marking procedure is finished.  
      It should be noted that it is possible to reuse the marking band  6  after washing it with toluene or the like.  
      B. The Operation Stage  
      [Step B- 1 ]: All parts of device  1  and special puncturing needles  71  and  72  are sterilized by gas sterilization or in an autoclave. At this point, the device is not yet assembled.  
      [Step B- 2 ]: The patient is put in the operating position on the operating table, and after fixing the head, the device mounting locations (Cr, Cl) and the operating field (region within the hatching lines) J, which is the region including a skull perforation location, are sterilized with isodine (see FIG.  11 ( a ) and ( b )). Then, the head is covered with cloth after draping, such that the operating field j can be seen.  
      [Step B- 3 ]: The surgeon makes an incision in the skin at the skull perforation location, drills a hole in the skull, and cuts through the dura mater.  
      [Step B- 4 ]: Now, the device  1  is assembled under clean conditions.  FIG. 2  shows the device  1  in its assembled state.  
      [Step B- 5 ]: Next, the distance from the point “0” on the scale  22  to the scalp surface matching line  36  (or  46 ) on the fixing frame  3  (or  4 ) is set to the distance Ra-Hc (or Lb-Hc). In this situation, the position of the fixing frame  3  (or  4 ) is set by sliding, and fixed in this position with the fixing screw  34  (or  44 ). Also, the fixing frame  3  (or  4 ) for which the distance is set is the frame on the surgery side.  
       FIG. 12  shows an example of setting the distance from the point “0” on the scale  22  to the scalp surface matching line  46  in accordance with the distance Lb-Hc (8.5 cm in this case) by sliding the left fixing frame  4  in the direction of the arrow K, for the case of a hemorrhage on the left.  
      If the left fixing frame  4  is fixed at a certain position as described above, then it stays fixed in this position until the end of the surgery, and the right fixing frame  3  on the opposite side is slid as described below when mounting the device  1  to the patient&#39;s head.  
      [Step B- 6 ]: The fixing needles  31  and  41  are positioned against the point Cr and the point Cl marked on the patient&#39;s head, while sliding the right fixing frame  3  on the opposite side in the direction of the arrow M, and after tightening such that the device is sufficiently fixed on the skull, the right fixing frame  3  is fixed at this position with the fixing screw  34  (see  FIG. 13 ).  
      [Step B- 7 ]: Then, in order to determine which guide groove  21  on the frame  2  with puncture guides to use for the puncturing, the entire device  1  is rotated around the point Cr and the point Cl to the location of the skull perforation, and the position of the optimum guide groove  21  at the location of the skull perforation is ascertained while inserting the puncturing needle  71  into the guide grooves  21  (see  FIG. 14 ). At this time, no puncturing is yet performed.  
      [Step B- 8 ]: The position of the optimum guide groove  21  at the location of the skull perforation is read from the scale  22  in units of 5 mm from the point “0”, and taken as Sx.  
      [Step B- 9 ]: The puncturing depth D corresponding to Sx is read from the following puncturing distance table.  
                                           0 mm-130 mm   35 mm-135 mm   70 mm-148 mm        5 mm-130 mm   40 mm-136 mm   75 mm-150 mm       10 mm-130 mm   45 mm-138 mm   80 mm-153 mm       15 mm-131 mm   50 mm-139 mm   85 mm-155 mm       20 mm-132 mm   55 mm-141 mm   90 mm-158 mm       25 mm-132 mm   60 mm-143 mm   95 mm-161 mm       30 mm-133 mm   65 mm-145 mm   100 mm-164 mm                   
 
      In this table, the left side of each field indicates the distance Sx from the point “0” on the scale  22 , whereas the right side indicates the puncturing depth D corresponding to that Sx. The puncturing distance D for Sx=0 mm corresponds substantially to the distance F from the frontal upper edge of the frame  2  with puncture guides to the fixing needles  31  and  41 .  
      [Step B- 10 ]: The puncturing depth D is marked with silk threads  73  or the like on two special puncturing needles  71  and  72 , one larger than the other (see  FIG. 15 ). Scale divisions of 1 cm are engraved in the puncturing needles  71  and  72 , so that this task can be performed easily.  
      As shown in  FIG. 16 , it is also possible to mark the position of the puncturing depth D with special stoppers  74  instead of with the silk threads  73 . These stoppers  74  include a puncturing needle insertion hole  741 , a positioning protrusion  742 , and a position fixing knob  743 . The puncturing needle  71 ,  72  is inserted into the puncturing needle insertion hole  741 , and the diameter of the puncturing needle hole  741  differs for the puncturing needle  71  and for the puncturing needle  72 , in accordance with the diameter of the puncturing needle  71 ,  72 . After the tip of the positioning protrusion  742  has been matched with the position of the puncturing depth D, the position fixing knob  743  is turned, its tip protrudes inside the puncturing needle hole  741 , and the stopper  74  is fixed/mounted in this position. Thus, the marking can be easily completed. As shown in  FIG. 16 , when using puncturing needles  71  and  72  with bold scale divisions every 5 cm, the positioning becomes even easier.  
      [Step B- 11 ]: The device  1  is rotated to the vicinity of the location of the skull perforation, and the puncturing needle  71  with the smaller diameter is tentatively inserted along the guide groove  21  determined in Step B- 8 . At this point, no puncturing into the brain is carried out yet. Then, as shown in  FIG. 15 , the device  1  is firmly fastened (by 3-point fixation) with the auxiliary fixing needle  51  to the head at the optimum position for puncturing.  
      [Step B- 12 ]: After the puncturing needle  71  with the smaller diameter has been inserted along the guide groove  21  that was determined in Step B- 8  to the depth that was marked in advance on the puncturing needle  71  (that is, until the silk thread  73  of the puncturing needle  71  reaches the frontal upper edge of the frame  2  with puncture guides, or until the front tip of the positioning protrusion  742  of the stopper  74  reaches the upper edge of the displacement prevention plate  23 ), the inner cylinder of the puncturing needle  71  is pulled out.  
      [Step B- 13 ]: A syringe is attached to the puncturing needle  71 , and after it has been confirmed that the tip of the puncturing needle  71  is in the center of the hematoma cavity by evacuation of a small amount of the hematoma, then the outer cylinder of the puncturing needle  71  is pulled out. Thus, a tract to the hematoma cavity is formed.  
      [Step B- 14 ]: Next, after the puncturing needle  72  with the larger diameter has been actually inserted along the same guide groove  21  up to the depth that has been marked in advance, the inner cylinder of the puncturing needle  72  is pulled out. Then, a syringe of about 10 cc (there is no particular limitation regarding the size, but if it is too large, there is the risk that the hematoma is evacuated too rapidly, leading to more hemorrhaging) is attached to the puncturing needle  72 , and the intended amount of hematoma is slowly evacuated.  
      [Step B- 15 ]: After evacuation of the hematoma is finished, the outer cylinder of the puncturing needle  72  is pulled out. The device  1  is removed from the head, the perforation location is closed, and the surgical procedure is finished.  
      (4) Modified Embodiment of the Present Invention  
      In the foregoing, the configuration of the device  1  and the marking band  6  according to the present embodiment as well as a method for using the same were explained, but the above method of use is merely one example, and there is no limitation to the method of use. For example, applications of the device  1  are not limited to evacuation of hematoma or hemorrhages, and the device  1  may also be used for such applications as evacuating cerebrospinal fluid, injecting antibiotics, hematoma dissolution with urokinase, or washing with saline solution.  
      Also, in the above-described method of use, puncturing needles  71  and  72  were guided to the location of the lesion within the brain, but the device  1  can also be used to guide tools other than the puncturing needles  71  and  72 , such as a (silicone) tube that needs to be guided to the location of the lesion within the brain for brain surgery.  
      Also the configurations of the device and the band of the present invention are not limited to the above-described configurations, various modifications within the scope of the invention are possible, as described below.  
      [4-A]First Modification Example of the Device  
       FIG. 17  is an exploded perspective view showing the overall configuration of a simplified stereotactic brain surgery device  100  (referred to below simply as “device  100 ”) in accordance with another embodiment of the present invention. It should be noted that to simplify explanations, portions that are the same as in the configuration of the above-described device  1  are marked by the same numerals, and their further explanation has been omitted.  
      In the device  100 , the fixing needles  31  and  41  are fastened from both sides by left and right fixing needle fastening knobs  311  and  411 . That is to say, male threaded portions are provided on the outer circumference of shafts  312  and  412  of the fixing needles  31  and  41 , female threaded portions are provided on the inner circumference of fitting holes  313  and  413  of the fixing frames  3  and  4 , the two are screwed together, and fixing needle fastening knobs  311  and  411  are attached to the rear ends of the shafts  312  and  412 . Consequently, when the fixing needle fastening knobs  311  and  411  are turned inward, the fixing needles  31  and  41  are fastened on the inner side, and the device  100  can be fastened firmly to the patient&#39;s head. A specific fixing method is for example as follows.  
      First, the fixing needle fastening knobs  311  and  411  are turned, and set to the state in which the fixing needles  31  and  41  are spread furthest apart, that is, to the state in which the brim-shaped plates  314  and  414  of the fixing needles  31  and  41  are closest to the fixing frames  3  and  4 . In this state, the fixing needles  31  and  41  are placed against the points Cr and Cl, as in the above-described Step B- 6 , the fixing frames  3  and  4  are firmly pressed vertically against the patient&#39;s skin with both hands, and while the fixing needles  31  and  41  are tightly pressed against the skull, the fixing frame  3  or  4  that is not on the afflicted side (surgery side) is fixed with the fixing screw  34  (or  44 ). The frame on the afflicted side has already been positioned and fixed, but it may be checked again at this time whether the fixing screw  34  (or  44 ) has not become loose. The knobs of the fixing screws  34  and  44  are provided with a relatively large diameter as shown in  FIG. 17 , in order to improve their operability.  
      Next, in order to strengthen the fixation, fine adjustment is performed with the fixing needle fastening knob  311  (or  411 ) that is not on the afflicted side. For this, the fixing needle fastening knob on the afflicted side is generally left alone, because there is the risk of deviation from the measured values. That is to say, care is taken that the brim-shaped plate of the fixing needle on the afflicted side does not sink further into the skin. If the brim-shaped plate of the fixing needle on the afflicted side clearly projects outward from the skin surface, then the fixing frame may be pressed on and fixed again, or a fine adjustment may be performed with the fixing needle fastening knob on the afflicted side.  
      Thus, the fixation of the device  100  on the patient&#39;s head can be easily strengthened by fastening and fine-tuning with the fixing needle fastening knobs  311  (or  411 ). After this, as in the above-described B- 11 , the device  100  is fixed at three points to the patient&#39;s head with the auxiliary fixing needle  51 . The fixing of the auxiliary fixing needle  51  to the patient&#39;s head is carried out by operating the knob portion  512  and the position fixing knob  53 . The position fixing knob  53  should be left somewhat loosened up to this operation, and fastened last. As shown in  FIG. 17 , in the device  100 , a washer  54  is provided between the position fixing knob  53  and the linking arm  52 , and the position fixing knob  53  is provided with a relatively large shape in order to improve its operability. The shaft length of the shaft  312  is made longer than that of the male thread  37 .  
      Moreover, the device  100  and the device  1  also differ structurally with regard to the aspects listed below:  
      (1) Other than the displacement prevention plate  23 , the device  100  is made of titanium or a titanium alloy. When the device is mounted during an operation, it is conceivable that tomographic images are taken by MRI, and adverse effects on the images due to mounting the device can be reduced by using a titanium alloy as the device material.  
      (2) For the material of the displacement prevention plate  23 , polycarbonate that has been sterilized in an autoclave is used. Furthermore, the left and right holes  245  of the displacement prevention plate  23  are not true circles but ovals lying on the side. With this structure, deformation (flexure) of the displacement prevention plate  23  can be prevented, even when sterilized in the state that the displacement prevention plate  23  is attached by the screws  242  to the main member  25  of the frame  2  with puncture guides.  
      (3) The heads of the screws  242  are formed to the same hexagonal shape as the brim-shaped plates  314  and  414  of the fixing needles  31  and  41 , and the nuts  315  and  415  for attaching the fixing needle fastening knobs  311  and  411  (the nut  415  is not shown in the figures). This is to ensure that fastening and removing these members can be performed using only a single tool, such as a wrench.  
      [4-B]Second Modification Example of the Device  
      It is also possible to apply the following modifications to the device  1 ,  100 .  
      In the device  1 ,  100 , the guide grooves  21  are engraved as guiding depressions in the frame  2  with puncture guides, but there is no limitation regarding the number, depth, width, length and profile shape of the guide grooves  21 , as long as the puncturing needles  71  and  72  can be guided by those grooves. For example, the number of the guide grooves  21  provided on the frame  2  with puncture guides may also be lower than in the configurations of the above-described embodiments. Also, in the above-described embodiment, the diameter of the outer cylinders of the puncturing needles  71  and  72  is 2 mm and 3 mm, respectively, and in this case, it is preferable that the depth of the guide grooves  21  is about 0.6 mm to 1.4 mm, and that the width of the guide grooves  21  is about 1.5 mm to 3 mm. Thus, the preferable depth and width of the guide grooves  21  differ depending on the diameter of the puncture needles  71  and  72  that are used, and there is no particular limitation to them.  
      Also, there is no particular limitation regarding the length of the guide grooves  21 , but in order to guide the puncturing needles  71  and  72  securely and in view of easy handling, it is preferable that the length of the center guide groove  210  is set to about 3 cm to 6 cm.  
      In the above-described embodiments, the cross-sectional shape of the guide grooves  21  was set to an inverse triangular shape in order to make their fabrication easy, but there is no particular limitation to this. However, when the cross section of the guide grooves  21  is arc-shaped, then the puncturing needles  71  and  72  may enter too deeply into the grooves, and the pressure on the puncturing needles  71  and  72  may become weak, so that it is preferable that the cross section of the guide grooves  21  is polygonal.  
      Moreover, instead of engraving guide grooves  21  into the frame  2  with puncture guides, it is also possible to provide the guide depressions of the present invention by letting a plurality of walls protrude from the frame  2  with puncture guides. That is to say, it is also possible to let a plurality of walls protrude instead of the guide grooves  21 , such that spaces between adjacent walls serve as the guide depressions of the present invention, and the puncturing needles  71  and  72  are inserted into these depressions.  
      The scales  22  are engraved into the main member  25  of the frame  2  with puncture guides, but the scales  22  may be also displayed on the displacement prevention plate  23  by printed characters or the like. It is also possible to engrave the guide grooves  21  on the displacement prevention plate  23  (on the side facing the main member  25  of the frame  2  with puncture guides).  
      The displacement prevention plate  23  is pressed against the main member  25  of the frame  2  with puncture guides by the coil spring  243 , which serves as a pressuring member, but the pressuring member is not limited to the coil spring  243 , and other elastic members such as rubber or plate springs are also possible.  
      In the above-described device  1 ,  100 , the depressions  32  and  42  in the fixing frames  3  and  4  are fitted to the main member  25  of the frame  2  with puncture guides and slid, but it is also possible to slide the fixing frames  3  and  4  by other configurations (for example by meshing a gear wheel with a rack). Moreover, as long as the fixing frames  3  and  4  can be displaced in the longitudinal direction of the frame  2  with puncture guides and fixed at any desired position on the frame  2  with puncture guides, the fixing frames  3  and  4  do not have to have a configuration in which they are slid.  
      In the above-described configurations, the auxiliary fixing support  5  is attached to the right fixing frame  3 , but it may also be attached to the left fixing frame  4  or provided on both sides.  
      In the above-described configurations, the fixing needles  31  and  41  are provided as fixing members for fixing the device  1 ,  100  on the patient&#39;s head, but it is also possible to fix the ends of the fixing frames  3  and  4  on the patient&#39;s head using an adhesive or sucking disks. In this case, if the ends of the fixing frames  3  and  4  and the portions fixed to the patient&#39;s head by an adhesive or the like are linked by a shaft, then the entire device  1 ,  100  can be rotated around this shaft to the location of the skull perforation.  
      There is also no particular limitation to the material of the device  1 ,  100 , and it is possible to use materials such as plastics or metals other than stainless steel or titanium (alloys), but a material suitable for sterilization is preferable. Also the displacement prevention plate  23  may be made of other materials than acrylic resin or polycarbonate.  
      Furthermore, design changes of the shape, size, length etc. of each member to achieve a suitable shape, size, length etc. are possible. For example, it is possible to change the design of the tip shape and size of the fixing needles  31  and  41  and the auxiliary fixing needle  51  to a suitable shape and size, or to change the shaft length of the screw portion  511  of the auxiliary fixing needle  51  to a suitable length. Furthermore, the tip  51   a  of the auxiliary fixing needle  51  may be configured such that it does not rotate in cooperation with a rotation of the shaft of the screw portion  511 . With this configuration, the tip  51   a  of the auxiliary fixing needle  51  is prevented from becoming entangled in the covering cloth or the like, when the device  1 ,  100  is fixed at three points with the auxiliary fixing needle  51 .  
      [4-C]Modification Example of the Band  
      The marking band  6  has a total of twelve mark sticks  67 , six on each of the two bands  61  and  62 , but the number of mark sticks  67  is not limited to this. It should be noted that when the number of mark sticks  67  is too low, then there is the risk that it is not possible to select a suitable plot  8  when selecting the left and right plots  8  in Step A- 8 , and it may be necessary to retake the CT. On the other hand, when the number of mark sticks  67  is too high, then the possibility increases that an error occurs when marking the positions of the mark sticks  67  corresponding to the plots  8  selected in Step A- 9 , so that the number of mark sticks  67  is preferably about 3 to 8 each on the left and right and more preferably about 4 to 7.  
      The mark sticks  67  serving as marker members are made of an aluminum alloy whose aluminum content is 99.77%, and further contains titanium, iron and silicon as components, but there is no particular limitation to the aluminum content when using an aluminum alloy. In order to provide the mark sticks  67  with sufficient flexibility to arrange them along the head&#39;s surface, it is preferable that the aluminum content is high (for example at least 70%).  
      Other than aluminum alloy, it is possible to use any metal or alloy that has a low X-ray permeability and produces few artifacts when taking CTs, such as aluminum, stainless steel, brass, copper or nichromium, for the metal rods (or metal wires) constituting the mark sticks  67 . Moreover, it is also possible to use materials other than metal, provided that those materials have low X-ray permeability and produce few artifacts when taking CTs, such as processed animal bone or teeth (ivory, human bone, fishbone or the like).  
      Moreover, the mark sticks  67  may also include other materials than the above. For example, the metal rods (or metal wires) made of any of the above-noted metals may be covered with an insulator.  
      The length of the mark sticks  67  is about 5 cm, and the distance between the mark sticks  67  is about 2 cm, but there is no limitation to this. The mark sticks  67  are formed into thin rods, but when they are too thin, it becomes difficult to insert them into the main member  65  of the band. On the other hand, when the metal roods are too thick, artifacts tend to occur, so that it is preferable that the cross-sectional diameter of the mark sticks  67  is about 1 mm to 2 mm. That is to say, it is preferable that the material and the thickness of the mark sticks  67  are such that the mark sticks  67  have enough flexibility to bring them into substantially full contact with the surface of the head by simply pressing them against the patient&#39;s head, and it is preferable that the mark sticks  67  are not too soft and that their material and thickness is such that their X-ray permeability is low and that artifacts do not tend to occur when taking CTs.  
      The two bands  61  and  62  constituting the marking bands  6  are made by connecting the two bands  61  and  62  together with the cloth tapes  63  and  64 , but there is no limitation to this, and it is also possible to make the marking band  6  by connecting the two bands  61  and  62  together by other means, such as paper tapes.  
      There is no particular limitation regarding the material of the two bands  61  and  62 , but a material with low stretchability in longitudinal direction is preferable, because there is the risk that the positions of the mark sticks  67  shift and accurate marking becomes impossible when the material is stretchable in the longitudinal direction. Moreover, a material that has enough flexibility to enable fitting on and wrapping around the patient&#39;s head is preferable.  
      (5) Advantages of the Embodiments  
      Regarding the advantages of the device  1  according to the present invention over the related art, the following explanations separately discuss the advantages over Komai-type devices and the advantages over the device disclosed in JP H11-137568A.  
      [5-A] Advantages Over Komai-Type Devices  
      (1) With a Komai-type device, it is necessary to mount the device already during the stage of taking the CT, whereas with the device  1 , there is no necessity to mount the device  1  when taking the CT, and it is enough to mount the device  1  in the operation room after taking the CT. Therefore, the device  1  is only used under sterilized conditions, which makes it more hygienic and reduces the possibility of infections greatly.  
      (2) Moreover, the device  1  is mounted in the operating room under anesthesia, so that it is less stressful on the patient.  
      (3) Since its configuration is simple, the device  1  can be assembled easily, so that the operating time can be shortened accordingly, and surgical invasion becomes lower. Moreover, when there are complications or accidents during the operation, such as respiratory insufficiency, then countermeasures can be taken more quickly, because the device  1  can be easily removed.  
      [5-B]Advantages Over the Device Disclosed in JP H11-137568A  
      (1) The tips  71   a  and  72   a  of the puncturing needles  71  and  72  are guided by the guided grooves  21  on the frame  2  with puncture guides to the location of the lesion within the brain, so that other members such as an arc-shaped frame are not necessary during the puncturing procedure. Thus, the procedure is easy in this respect, and has excellent operability. Furthermore, a curved member, such as an arc-shaped frame, is not necessary, so that sterilization is easy and the device is hygienic, and the device can be fabricated more easily and at lower cost.  
      (2) Even while one of the puncturing needles  71  and  72  with different diameters is inserted into the brain, that puncturing needle  71  or  72  is sandwiched by the main member of the frame  2  for puncture guides and the displacement prevention plate  23  and displacement can be prevented reliably. Consequently, destruction of tissue is minimal, so that a device configuration with high security preventing further bleeding is obtained. Moreover, a plurality of puncturing needles  71  and  72  of different diameters can be guided by this configuration, so that it is possible to first provide a tract (path) to the hematoma cavity with the thinner puncturing needle  71 , and then insert into that tract the puncturing needle  72  for evacuating the hematoma with the same device  1 . In this surgical procedure, further bleeding tends not to occur and it is gentle on the surrounding brain tissue, so that the device configuration also provides high security regarding this aspect.  
      (3) The auxiliary fixing support  5  has a simple configuration and it is easy to adjust the angle θ and the distance E, so that the position where the device is fixed to the patient&#39;s head can be freely selected within an adjustment range with the auxiliary fixing needle  51 . That is to say, the range over which fixing with the auxiliary fixing needle  51  is possible is large, and accordingly, it is possible to select a safer fixing position.  
      (4) The principal members are of substantially linear shape, so that fabrication of the device is accordingly inexpensive, and sterilization can be performed reliably, making it hygienic.  
      The invention may be embodied in other forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.  
     INDUSTRIAL APPLICABILITY  
      The present invention relates to simplified stereotactic brain surgery devices used for surgery on cerebral diseases such as hypertensive cerebral hemorrhages, brain tumors, brain abscesses, hydrocephalus, or cerebral cysts, and to bands used for determining the position at which such a device is mounted on a patient&#39;s head, and can be used for various kinds of brain surgery, such as evacuation surgery of hematoma or hemorrhages, evacuation of cerebrospinal fluid, injecting antibiotics, hematoma dissolution with urokinase, or washing with saline solution.