Abstract:
Systems and techniques for implanting medical devices. In one aspect, an apparatus includes a flexible base member that can be flexed manually to conform to a contour of an anatomy, the base member including a radioscopic indicium that has a characteristic such that, under radioscopic imaging, passage of a skin-penetrating electromagnetic radiation is hindered to an extent that is distinguishable from a hindrance of the electromagnetic radiation by another portion of the base member.

Description:
BACKGROUND 
     This disclosure relates to implanting medical devices. 
     SUMMARY 
     Systems and techniques for implanting medical devices are described. In one aspect, an apparatus for implanting a medical device includes a flexible base member that can be flexed manually to conform to a contour of an anatomy, the base member including a radioscopic indicium that has a characteristic such that, under radioscopic imaging, passage of a skin-penetrating electromagnetic radiation is hindered to an extent that is distinguishable from a hindrance of the electromagnetic radiation by another portion of the base member. 
     This and other aspects can include one or more of the following features. The base member can include an illustration of the medical device. The illustrated medical device can include a charging element for accumulating potential energy at the medical device. The medical device illustration can include a marking selected to correspond to feature found on the medical device. The base member can include a sheet-like polymeric material. The apparatus can include an adhesive to removably adhere the base member to the contour of the anatomy. 
     The base member can also include a visual indicium that is visible to a naked eye and is positioned on the base so that when the visual indicium is properly arranged relative to an anatomical feature of a patient, the base can guide the implantation of the medical device. The apparatus can also include a surgical cutout that spans the base member and is positioned on the base member to identify an anatomical location that is relevant to an implantation when the base member is properly arranged. The radioscopic indicium can demarcate the position of the surgical cutout under radioscopic imaging. 
     The apparatus can also include an alignment tab that extends outward from the base member and that is dimensioned so that when the alignment tab is properly arranged relative to an anatomical feature of a patient. The base can guide the implantation of the medical device. The radioscopic indicium can be positioned on the base so that when the radioscopic indicium is properly arranged relative to an anatomical feature of a patient, the base can guide the implantation of the medical device. The radioscopic indicium can be positioned on the base to guide the implantation of the medical device. 
     In another aspect, a system includes a medical device that includes a charging element for accumulating potential energy at a medical device and a base member that can be flexed manually to conform to a contour of an anatomy, the base member including a radioscopic indicium that, under radioscopic imaging, hinders passage of a skin-penetrating electromagnetic radiation to an extent that is distinguishable from a hindrance of the electromagnetic radiation by another portion of the base member. 
     This and other aspects can include one or more of the following features. The charging element can include a charging coil. 
     In another aspect, a method includes arranging an apparatus for implanting a medical device relative to an anatomical feature and implanting, under guidance of the apparatus, the medical device. The apparatus for implanting the medical device includes one or more of a visual indicium that is visible to a naked eye and a radioscopic indicium that, under radioscopic imaging, hinders passage of a skin-penetrating electromagnetic radiation to an extent that is distinguishable from a hindrance of the electromagnetic radiation by another portion of the apparatus. The one or more indicia are positioned on the apparatus to guide implantation of the medical device. The medical device includes a charging element for accumulating potential energy at the medical device and the guidance of the apparatus arranges the charging element for the effective accumulation of the potential energy. 
     This and other aspects can include one or more of the following features. The apparatus can be flexed manually to conform to a contour of an anatomy. Implanting the medical device under the guidance of the apparatus can include radioscopically imaging the medical device and the radioscopic indicium of the apparatus. For example, the medical device can be radioscopically imaged to confirm that the charging element is arranged properly. 
     The apparatus can be arranged to align the visual indicium with the anatomical feature and/or to align a mechanical element with the anatomical feature. For example, an outwardly-extending arm can be contacted to the anatomical feature. Arranging the apparatus can also include aligning, with the anatomical feature, a preformed, solid element that retains a shape. 
     The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIGS. 1 ,  2 ,  3 ,  6  are schematic representations of apparatus for implanting one or more medical devices. 
         FIGS. 4 ,  5  are schematic representations of cross-sections of sheet-like materials that can be used to form a base of apparatus for implanting one or more medical devices. 
         FIGS. 7 and 8  are schematic representations of a deployment of an apparatus for implanting one or more medical devices. 
         FIG. 9A  is a schematic representation of an apparatus for implanting one or more medical devices. 
         FIG. 9B  is a schematic representation of various layers that can be assembled to form the apparatus of  FIG. 9A . 
         FIGS. 10-15  are schematic representations of a deployment of an apparatus for implanting one or more medical devices. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic representation of an apparatus  100  for implanting one or more medical devices. Apparatus  100  includes a sterile, sheet-like base  105  that includes markings, patterns, and other indicia to indicate the proper placement and alignment of a medical device to medical personnel. Base  105  can be positioned to align indicia thereon with anatomical features of a patient and/or a medical device during or after implantation. Medical personnel can rely upon the arrangement of base  105  to ensure that the positioning and alignment of the medical device is proper. 
     In the illustrated implementation, base  105  defines a surgical cutout  110  and includes both visual indicia  115 ,  120 ,  125 ,  130 ,  135 ,  140  and radioscopic indicia  145 ,  150 ,  155 ,  160 ,  165 ,  170 . Surgical cutout  110  traverses base  105  and, when base  105  is properly positioned, can identify an anatomical location that is relevant to an implantation. For example, surgical cutout  110  can be dimensioned and positioned to allow medical personnel to implant a medical device therethrough, e.g., by allowing medical personnel to incise skin underlying base  105  or penetrate the skin using minimally invasive surgical devices. As another example, surgical cutout  110  can be dimensioned and positioned to allow medical personnel to mark the skin of the a patient. 
     Visual indicia  115 ,  120 ,  125 ,  130 ,  135 ,  140  are markings on base  105  that are visible to the naked eye. Some visual indicia can be arranged on base  105  so that when they are properly positioned relative to anatomical features of a patient, base  105 , cutout  110 , and indicia thereon guide medical personnel in the proper implantation of one or more medical devices. The indicia on base  105  that guide medical personnel in the proper implantation can be visual and/or radioscopic indicia. 
     In some implementations, visual indicia  115 ,  120 ,  135 ,  140  can be dimensioned and arranged to be positioned relative to the midline of the dorsal side of the neck of a patient before, during, or after a proper implantation. Visual indicia  125 ,  130  can be dimensioned and arranged to be positioned relative to the intermastoid line on the dorsal side of the neck at the base of the head of a patient before, during, or after a proper implantation. Visual indicia can be dimensioned and arranged to be positioned relative to the external occipital protuberance of the head of a patient before, during, or after a proper implantation. Such a positioning of visual indicia  115 ,  120 ,  125 ,  130 ,  135 ,  140  can position and align base  105  for proper implantation of one or more medical devices. In general, visual indicia  115 ,  120 ,  125 ,  130 ,  135 ,  140  can be transparent to x-rays or other skin-penetrating electromagnetic radiation, but this is not necessarily the case. 
     Radioscopic indicia  145 ,  150 ,  155 ,  160 ,  165 ,  170  are markings on base  105  that hinder or prevent the passage of x-rays or other skin-penetrating electromagnetic radiation. For example, radioscopic indicia  145 ,  150 ,  155 ,  160 ,  165 ,  170  can be radiopaque. Radioscopic indicia  145 ,  150 ,  155 ,  160 ,  165 ,  170  can made from materials such as lead, bismuth, barium, tungsten, platinum, tantalum, gold, their alloys, and the like. Radioscopic indicia can be dimensioned and arranged on base  105  so that when they are properly positioned relative to anatomical features of a patient, base  105 , cutout  110 , and indicia thereon guide medical personnel in the proper implantation of one or more medical devices. The indicia on base  105  that guide medical personnel in the proper implantation can be visual and/or radioscopic indicia. 
     Radioscopic indicia  145  can be a set of lines that demarcate the edges of surgical cutout  110  under radioscopic imaging. Radioscopic indicia  150  can be a set of dots that demarcate the corners of surgical cutout  110  under radioscopic imaging. Radioscopic indicia  155 ,  160  can be sets of ruler marks that demarcate distance along the intermastoid line on the dorsal side of the neck of a patient when visual indicia  125 ,  130  are properly positioned relative to the intermastoid line. Radioscopic indicia  165 ,  170  can be sets of ruler marks that demarcate distance along the midline of dorsal side of the neck of a patient when visual indicia  115 ,  120 ,  135 ,  140  are properly positioned relative to the midline. In general, radioscopic indicia  145 ,  150 ,  155 ,  160 ,  165 ,  170  are also visible to the naked eye, although this is not necessarily the case. For example, radioscopic indicia  145 ,  150 ,  155 ,  160 ,  165 ,  170  can be embedded in an opaque base  105 . 
       FIG. 2  is a schematic representation of an apparatus  200  for implanting one or more medical devices. In addition to base  105 , cutout  110 , and various visual and radioscopic indicia, apparatus  200  also includes a diagram  205  of one or more properly implanted medical devices. Diagram  205  is visible to the naked eye and can illustrate the proper arrangement of medical devices before, during, or after implantation to medical personnel. 
     The illustrated diagram  205  includes a representation  210  of a first medical device and a representation  215  of a second medical device. The medical devices represented by representations  210 ,  215  can be, e.g., microstimulators such as the BION microstimulator developed by Advanced Bionics (Sylmar, Calif.). The standard BION is a leadless microstimulator and is a cylinder that is about 3 mm in diameter and between about 2 and 3 cm in length. This form factor allows the BION to be implanted with relative ease and rapidity, e.g., via endoscopic or laparoscopic techniques. In some implementations, the BION consists of only two electrodes: a reference, or indifferent, electrode at one end and an active electrode at the other end. Various features and details associated with the manufacture, operation, and use of BION implantable microstimulators are described in U.S. Pat. No. 5,193,539, U.S. Pat. No. 5,193,540, U.S. Pat. No. 5,312,439, U.S. Pat. No. 5,324,316, U.S. Pat. No. 5,405,367, U.S. Pat. No. 6,051,017, PCT Publication No. WO 98/37926, PCT Publication No. WO 98/43700, PCT Publication No. WO 98/43701, and the publication entitled “Micromodular Implants to Provide September Electrical Stimulation of Paralyzed Muscles and Limbs” by Cameron, et al. in IEEE Transactions on Biomedical Engineering, Vol. 44, No. 9, pages 781 790 (1997), the contents of all of which are incorporated herein by reference. 
     Representation  210  includes a first set of markings  220  and a second set of markings  225 . Representation  215  includes a set of markings  230 . Marking sets  220 ,  225 ,  230  can be selected to correspond to selected markings or other features found on the first and second medical device (not shown). Marking sets  220 ,  225  can be designed so that medical personnel can identify, align, and position the first medical device by mimicking the alignment and position of marking sets  220 ,  225  with the first medical device. Marking set  230  can be designed so that medical personnel can also align and position such a second medical device by mimicking the alignment and position of marking set  230  with the second medical device. 
     In some implementations, apparatus  200  can be adapted to illustrate the proper arrangement of a charging element of a medical device after implantation. A charging element is a device that participates in the accumulation of potential energy at a medical device. One example of a charging element is a conducting coil that can respond to a magnetic or electrical field generated outside a patient&#39;s body. Another example of a charging element is a photovoltaic cell that can respond to light or other electromagnetic radiation generated outside the body. Yet another example of a charging element is a mechanical element such as a piezoelectric resonator that can respond to acoustic oscillations or other mechanical disturbance generated outside the body. Proper arrangement of a charging element can help ensure that post-implantation charging of a medical device is effective. 
     Diagram  205  of apparatus  200  can be adapted to illustrate proper arrangement of a charging element after implantation. For example, a charging element (and/or a device that includes a charging element) can be illustrated in representations  210 ,  215 . As another example, proper alignment of a charging element (and/or a device that includes a charging element) can be identified from marking sets  220 ,  225 ,  230 . 
     In some implementations, apparatus  200  can be adapted to illustrate the proper arrangement of one or more electrode leads of a leaded stimulator after implantation. Electrode leads are insulated conductors that carry electrical current from a device to one or more electrode. In some implementations, electrode leads can be illustrated in representations  210 ,  215 . As another example, proper alignment of electrode leads can be identifiable from marking sets  220 ,  225 ,  230 . 
     In some implementations, apparatus  200  can be adapted to illustrate the location of a target for electrical stimulation. For example, the location of nerves such as the occipital nerves can be illustrated. In some implementations, apparatus  200  can also provide visual and radioscopic guides for the placement of leads, devices, needles or percutaneous electrodes, RF ablation needles, and the like relative to a target for stimulation. 
       FIG. 3  is a schematic representation of an apparatus  300  for implanting one or more medical devices. In addition to base  105 , cutout  110 , and various visual and radioscopic indicia, apparatus  300  can also include a pair of alignment tabs  305 . Alignment tabs  305  are mechanical elements that are aligned and dimensioned so that proper arrangement of tabs  305  relative to anatomical features positions base  105 , cutout  110 , and indicia thereon to guide medical personnel in the proper implantation of one or more medical devices. For example, alignment tabs  305  can be aligned and dimensioned to extend outwardly away from base  105  so that when alignment tabs  305  are arranged to contact the mastoid processes of a patient, base  105 , cutout  110 , and indicia thereon can guide medical personnel in the proper implantation of one or more medical devices in the dorsal side of the neck of a patient. As another example, alignment tabs  305  can be aligned and dimensioned to extend outwardly away from base  105  so that when alignment tabs  305  are arranged to contact the external occipital protuberance of a patient and the spinal process on the vertebrae in the neck, base  105 , cutout  110 , and indicia thereon can guide medical personnel in the proper implantation of one or more medical devices in the dorsal side of the neck of a patient. 
     In some implementations, alignment tabs  305  are formed from the same sheet-like material as base  105 . For example, alignment tabs  305  and base  105  can be formed from a flexible sheet that medical personnel can manually conform to the contours of a patient&#39;s anatomy. 
       FIG. 4  is a schematic representation of cross-section  4 - 4  of a sheet-like material  400  that can be used to form base  105  before deployment in implanting medical devices. Material  400  includes a base layer  405 , an adhesive layer  410 , and a peel-away backing layer  415 . Base layer  405  can be a polymeric material that is formed into a sheet having a pair of generally planar outer surfaces  420 ,  425 . Base layer  405  can be flexible in that medical personnel can manually conform material  400  to the contours of a patient&#39;s anatomy. For example, base layer  405  can include a polyester, a nylon, a paper, a polypropylene, a polyurethane foam, and/or a stainless steel foil and can have a thickness of, e.g., 0.1 to 3 mm. Visual indicia (such as visual indicia  115 ,  120 ) and radiographic indicia (such as radiographic indicia  160 ) can be affixed to surface  425  of base layer  405 . 
     All or a portion of surface  420  of base layer  405  can be coated with adhesive layer  410 . Adhesive layer  410  can include adhesive that adheres both to base layer  405  and to human skin but is removable from human skin when pulled. Adhesive layer  410  can be biocompatible in that contact with human skin does not result in an adverse allergic or other reaction. Adhesive layer  410  can be flexible in that medical personnel can manually conform material  400  to the contours of a patient&#39;s anatomy without excessive interference from adhesive layer  410 . In some implementations, adhesive layer  410  can be made from medical grade acrylic adhesive. 
     Peel-away backing layer  415  is a sheet having a pair of generally planar outer surfaces  430 ,  435 . Surface  430  can removably contact adhesive layer  410  so that peel-away backing layer  415  can be peeled away and adhesive layer  410  exposed for deployment on a patient&#39;s anatomy. In some implementations, peel-away backing layer  415  can be made from Kraft release liner and can be, e.g., 0.1-2 mm thick. 
       FIG. 5  is a schematic representation of cross-section  5 - 5  of a sheet-like material  500  that can be used to form base  105  before deployment in implanting medical devices. In addition to base layer  405 , adhesive layer  410 , and peel-away backing layer  415 , material  500  includes a cover layer  505 . Cover layer  505  can be a transparent polymeric material that covers surface  425  of base layer  405 , along with any visual and radiographic indicia thereon, such as visual indicia  115 ,  120  and radiographic indicium  160 . Cover layer  505  can shield such indicia from damage during the handling of apparatus  100 . Cover layer  505  can be flexible in that medical personnel can manually conform material  500  to the contours of a patient&#39;s anatomy without excessive interference from cover layer  505 . Cover layer  505  can be affixed to surface  425  of base layer  405  using any of a number of different techniques, including, e.g., lamination, roll coating, spray coating, spin coating, dip coating, and the like. In some implementations, cover layer  505  can include a polyester, a nylon, a paper, a polypropylene, a polyurethane foam, and/or a stainless steel foil and can have a thickness of, e.g., 0.1 to 3 mm. 
       FIG. 6  is a schematic representation of an apparatus  600  for implanting one or more medical devices. Apparatus  600  is a preformed, solid element that retains a shape dimensioned to be aligned with anatomical features of a patient. For example, apparatus  600  can include a base  605  and a pair of preformed alignment arms  610 . Base  605  can be a generally flat member that is shaped to mimic the contours of a patient&#39;s neck. Base  605  can define a surgical cutout and include visual indicia and radioscopic indicia to guide the implantation of one or more medical devices. 
     Alignment arms  610  extend outward from base  605  and are shaped to mimic the contours of a patient&#39;s anatomy. Alignment arms  610  are shaped so that proper arrangement of arms  610  relative to anatomical features positions apparatus  600 , and any indicia thereon, to guide a proper implantation of one or more medical devices. For example, alignment arms  610  can be aligned and dimensioned so that when they are arranged to contact the mastoid processes of a patient, apparatus  600  and indicia thereon can guide medical personnel in the proper implantation of one or more medical devices in the dorsal side of the neck of a patient. 
       FIGS. 7 and 8  are schematic representations of a deployment of an apparatus, such as apparatus  100 ,  200 ,  300 ,  600 , for implanting one or more medical devices. In particular,  FIG. 7  illustrates the deployment as is visible to the naked eye, and  FIG. 8  illustrates the deployment under radiographic imaging. 
     In operation, medical personnel can first prepare an apparatus for implanting one or more medical devices as needed. For example, an apparatus for implanting medical devices can be cleaned and sterilized. As another example, a peel-away backing can be removed from such an apparatus so that an adhesive layer can adhere to a patient. 
     The apparatus for implanting medical devices can be arranged relative to anatomical features of a patient. For example, alignment tabs and/or arms can be aligned with anatomical features such as the mastoid processes to properly position a base, along with any surgical cutouts, visual indicia, and/or radioscopic indicia thereon. As another example, visual indicia and/or radioscopic indicia can be aligned with anatomical features such as the intermastoid line and the midline of a patient to properly position a base, along with any surgical cutouts, visual indicia, and/or radioscopic indicia thereon. After it is arranged properly, the apparatus for implanting medical devices can be adhered to the patient, e.g., by pressing the apparatus against the patient&#39;s skin. 
     Using the guidance provided by properly aligned visual and/or radioscopic indicia, medical personnel can implant one or more medical devices. For example, a proper location for an incision can be identified from visual indicia. As another example, the proper insertion path or depth for a cannula that is used to implant a medical device can be identified from radioscopic indicia. As another example, dissection trajectories can be identified from visual indicia. As yet another example, the proper arrangement of a charging element of an implanted medical device can be confirmed using visual and/or radiographic indicia. A further example is illustrated in  FIG. 7 , which shows the positioning of an incision  705  relative to surgical cutouts, visual indicia, and radioscopic indicia on a base. A yet further example is illustrated in  FIG. 8 , which shows the positioning of implanted medical devices  802 ,  804  relative to radioscopic indicia on the base. 
     In some implementations, an apparatus for implanting medical devices include visual and radioscopic indicia for positioning of multiple devices relative anatomical targets. For example, an apparatus for implanting medical devices can be placed on a patient. Medical personnel can use a percutaneous stimulating needle to locate a nerve and then reposition the apparatus for implanting medical devices based on the location of the nerve identified using percutaneous stimulation. Even if the percutaneous needle is subsequently removed, the positioning of the apparatus for implanting medical devices can be used to position and/or implant other medical devices. For example, a medical device with stimulating electrodes can be implanted at the site identified using percutaneous stimulation. 
     In some implementations, medical personnel can use one or more indicia on an apparatus for implanting medical devices as a guide for marking the skin of a patient. For example, the skin of a patient can be marked using visual and/or radioscopic indicia such as ink. Such marks can then be used in implanting a medical device, even after the apparatus for implanting medical devices has been removed from the skin. At times, the apparatus for implanting medical devices can be returned to the skin after an incision is made and/or a device is implanted. Using the visual and/or radioscopic indicia on the apparatus for implanting medical devices, medical personnel can confirm that an incision and/or implanted device is properly positioned. 
     After implantation, the one or more implanted medical devices can function unhindered by misplacement or misalignment. For example, microstimulators can stimulate nerve or cells. Microstimulators implanted in the dorsal side of the neck can stimulate nerves for treating migraine headaches. As another example, an implanted medical device that includes a charging element can be charged effectively, e.g., when an electric and/or magnetic field is generated in the vicinity of the implanted medical device using a device positioned outside of the patient&#39;s skin. 
       FIG. 9A  is a schematic representation of an apparatus  800  for implanting one or more medical devices. Apparatus  800  includes a base  805  that can be positioned to align indicia thereon with anatomical features of a patient and/or a medical device during or after implantation. 
     Base  805  includes a diagram  810  that includes representations  815 ,  820  or medical devices. Diagram  810  is visible to the naked eye and can illustrate the proper arrangement of medical devices before, during, or after implantation to medical personnel. 
     A pair of alignment tabs  825 ,  830  extend outwardly from base  805 . As shown, alignment tab  825  is longer than alignment tab  830  and hence extends further away from base  805 . In operation, alignment tabs are to be aligned longitudinally along the midline of a patient and can be positioned relative to the occipital protuberance, as discussed further below. 
     Base  805  includes a collection of surgical cutouts  835 ,  840 ,  845 ,  850 ,  855 ,  860 , a collection of perimeter features  862 ,  864 ,  866 , a collection of visual indicia  868 ,  70 ,  872 ,  874 ,  876 ,  878 , and a collection of combined visual and radioscopic indicia  880 ,  882 ,  884 ,  886 . 
     Surgical cutouts  835 ,  840 ,  845 ,  850 ,  855 ,  860  traverse base  805 . Surgical cutouts  835 ,  840 ,  845 ,  850  are generally circular in shape and are dimensioned to pass the tip of a sterile skin marker so that a collection of generally circular marks can be made on the skin of a patient when base  805  is properly positioned. Surgical cutouts  855 ,  860  are generally elongate in shape and are also dimensioned to pass the tip of a sterile skin marker so that a pair of generally elongate marks can be made on the skin of a patient when base  805  is properly positioned. 
     Perimeter features  862 ,  864 ,  866  are inwardly sloping depressions along a perimeter  890  of base  805 . Perimeter features  862 ,  864 ,  866  are dimensioned to receive the tip of a sterile skin marker so that a collection of generally marks can be made on the skin of a patient when base  805  is properly positioned, as discussed further below. 
     Visual indicia  868 ,  870 ,  872 ,  874 ,  876 ,  878  are markings on base  105  that are visible to the naked eye. Visual indicia  868 ,  870 ,  872 ,  874 ,  876 ,  878  play various roles in the implantation of medical devices. For example, visual indicia  868  generally resembles a two-headed arrow and indicates a range that can be aligned with the occipital protuberance of a patient when base  805  is properly positioned with respect thereto. Visual indicia  870  is a collection of one or more numeric indicia that indicate a number of units distance from a center point P which is in the middle of cutout  860 . Visual indicia  872  is a collection of one or more alphanumeric indicia (i.e., the word “ROSTRAL”) that guides medical personnel in the proper alignment of base  805  relative to anatomical features of a patient. In particular, visual indicia  870  indicates that alignment tab  825  is to be positioned rostrally to the occipital protuberance of a patient when base  805  is properly positioned with respect thereto. 
     Visual indicia  874  is a collection of fine and coarse ruler marks that demarcate distance units from center point P. Visual indicia  876  is a collection of one or more alphanumeric indicia (i.e., the word “MIDLINE”) that guides medical personnel in the proper alignment of base  805  relative to anatomical features of a patient. In particular, visual indicia  876  indicates a line that is to be positioned along the midline of a patient when base  805  is properly positioned with respect thereto. Visual indicia  878  is a pair of generally triangular features that indicate the intermastoid line on the dorsal side of the neck of a patient when base  805  is properly positioned with respect thereto. 
     Combined visual and radioscopic indicia  880 ,  882 ,  884 ,  886  are visible both to the naked eye and under radioscopic imaging to guide medical personnel in the proper implantation of one or more medical devices. Indicia  880 ,  882 ,  884 ,  886  form a generally rectangular frame around point P. 
       FIG. 9B  is a schematic representation of various layers  905 ,  910 ,  915 ,  920  that can be assembled to form apparatus  800  ( FIG. 9A ). Top layer  905  is a polymeric film that has been marked with a laser to form diagram  810 , visual indicia  868 ,  870 ,  872 ,  874 ,  876 ,  878 , and visually-apparent aspects of combined visual and radioscopic indicia  880 ,  882 ,  884 ,  886  ( FIG. 8 ). In some implementations, the polymeric film of top layer  905  is a 2 mil thick white polyester layer. Top layer  905  can be coated with an adhesive, such as P-34 adhesive, on its underside. 
     Insert layer  910  is a generally rectangular metallic frame insert that includes rounded edges  925 . Rounded edges  925  are dimensioned and positioned to allow surgical cutouts  835 ,  840 ,  845 ,  850  to pass the tip of a sterile skin marker when layers  905 ,  910 ,  915 ,  920  have been assembled to form apparatus  800  ( FIG. 8 ). In some implementations, insert layer  910  can be formed from a lead foil or a low density polyethylene composite such as RTP 799 AX 113633AZ (RTP Company, Winona, Minn.). 
     Substrate layer  915  is a foam polymeric sheet substrate. In some implementations, substrate layer  915  can be formed of a 1/32 inch thick polyethylene layer, such as Voltek cross-linked polyethylene #60E-white (Voltek division of Sekesui America Corporation, MA). In some implementations, substrate layer  915  can be coated with a medical grade acrylic adhesive on its underside, such as Solutia #RA788 (Solutia, St. Louis, Mo.). 
     Liner layer  920  is a generally rectangular backing layer that can be peeled away from an adhesive on the underside of substrate layer  915 . In some implementations, liner layer can be formed from a split release liner such as HDPE and bleach Kraft paper. 
       FIGS. 10-15  are schematic representations of a deployment of an apparatus, such as apparatus  800 , for implanting one or more medical devices. In particular,  FIG. 10  illustrates the dorsal side  1000  of a patient. The patient&#39;s intermastoid line  1005 , midline  1010 , and occipital protuberance  1015  are all found on dorsal side  1000 . 
     As shown in  FIG. 10 , using a sterile skin marker  1020 , a surgeon or other medical personnel can mark the apex of occipital protuberance  1015  with an “X” mark  1025 . Based on the location of occipital protuberance  1015 , the surgeon can draw a line  1030  caudally along the midline  1010 . Line  1030  can be, e.g., between 7 and 10 cm long. 
     As shown in  FIG. 11 , after any liner has been removed from apparatus  800 , the surgeon can align surgical cutouts  855 ,  860  of apparatus  800  with line  1030  along the patient&#39;s midline. Moreover, visual indicia  868  can be aligned with “X” mark  1025 . While maintaining this alignment, apparatus  800  can be pressed against the skin of the patient to position center point P in cutout  860  approximately 2-3 cm caudal to the occipital protuberance. 
     As shown in  FIG. 12 , under the guidance of apparatus  800 , a surgeon can add additional marks to the skin of the patient using sterile skin marker  1020 . In particular, as shown in  FIG. 13 , a surgeon can make a collection of marks  1305 ,  1310 ,  1315  based on the positions of perimeter features  862 ,  864 ,  866 , respectively, and a collection of marks  1320 ,  1325 ,  1330 ,  1335  based on the positions of surgical cutouts  835 ,  840 ,  845 ,  850 , respectively. The surgeon can also embolden line  1030  using a mark  1340  using cutout  860 . In some implementations, apparatus  800  can be removed after marks  1305 ,  1310 ,  1315 ,  1320 ,  1325 ,  1330 ,  1335 ,  1340  have been made. 
     As shown in  FIG. 14 , using sterile skin marker  1020 , the surgeon can connect marks  1320 ,  1325 ,  1330 ,  1335  to form a charging window  1405  that demarcates a charging window. Charging window  1405  is the boundary within which acceptable charging of an implantable medical device can occur. Further, the surgeon can draw a transverse line  1410  between marks  1305 ,  1310  to further assist the surgeon in the implantation of a medical device. 
     As shown in  FIG. 15 , using a scalpel  1505 , the surgeon can create an incision  1510  along midline  1010  at the former position of mark  1340  within charging window  1405 . In some implementations, incision  1510  is about 1.5 cm long and can be used to implant one or more medical devices. In some implementations, after implantations, apparatus  800  can be repositioned using one or more marks on the dorsal side of the patient to verify that any implanted device is positioned and aligned properly. The verification can be performed, e.g., via palpation and/or radiographic imaging. 
     A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. For example, an apparatus for implanting one or more medical devices need not include a surgical cutout at all. Rather, features on a perimeter of an apparatus for implanting medical devices can identify an anatomical location that is relevant to an implantation. As another example, a surgical membrane such as TAGADERM or IOBAN (3M, St. Paul, Minn.) can identify an anatomical location that is relevant to an implantation. A surgical knife or other tool can be used to pierce such a surgical membrane after arrangement of the apparatus. 
     As another example, an apparatus for implanting one or more medical devices need not be adhered to a patient during implantation. For example, an apparatus for implanting one or more medical devices can be strapped, tied, sutured to, or pressed against a patient during implantation. As another example, an apparatus for implanting one or more medical devices can be made from paper, metal, or other materials. 
     As yet another example, alignment tabs and arms can extend in directions other than those illustrated. For example, an alignment tab or arm can extend into a surgical cutout. As another example, an alignment tab or arm can extend to another anatomical feature, such as the occipital protuberance. 
     As yet another example, an apparatus for implanting one or more medical devices can be used to mark a patient. The marks can guide the implantation of one or more medical devices. For example, an apparatus can include transferable elements that can be transferred from the apparatus to the skin of a patient to mark the patient after arrangement of the apparatus. The transferred elements can thus create visual and/or radiographic indicia on the patient. As another example, an apparatus can include holes or other guide elements that can guide the drawing of marks on the skin of a patient. The drawn marks can thus create visual and/or radiographic indicia on the patient. 
     As yet another example, a wide variety of numeric and alphanumeric indicia can be used on an apparatus for implanting one or more medical devices. Examples of such indicia include “charging window,” “intermastoid line,” “incision,” “align occipital protuberance here,” and the like. 
     Accordingly, other implementations are within the scope of the claims.