Abstract:
A method of preparing an opening formed in a penis for reception of a penile prosthetic includes measuring a length of the opening formed in the penis with a shaft of an instrument, and moving a dilation head longitudinally along the shaft of the instrument and dilating a diameter of the opening formed in the penis.

Description:
BACKGROUND 
     Implanted penile prostheses address erectile dysfunction in men. 
     In a typical implantation procedure, the penis of the patient is incised in a corporotomy to expose a pair of corpora cavernosa that are aligned axially in a side-by-side orientation within the penis. A cutting implement, such as a curved Mayo scissors, is employed to penetrate the fascia of the penis and form an opening accessing each corpora cavernosum. Thereafter, a tool (e.g., a “Furlow” introducer) is inserted into each corpora cavernosum to measure a length of the penis distally and proximally from a “stay” suture or other stationary landmark located near the opening formed in the fascia. Subsequently, each corpora cavernosum is dilated with at least one separate dilation tool, and often multiple dilation tools. For example, each corpora cavernosum is dilated by introducing gradually larger stainless steel rods into the corpora cavernosum to form a recess in the penis that is sized to receive a cylinder of the penile prosthesis. 
     The above-described procedure has proven effective in the implantation of penile prostheses. However, practitioners have expressed a continuing desire for more efficient and cost effective tools and procedures for implanting penile prostheses. 
     SUMMARY 
     One aspect provides a method of preparing an opening formed in a penis for reception of a penile prosthetic. The method includes measuring a length of the opening formed in the penis with a shaft of an instrument, and moving a dilation head longitudinally along the shaft of the instrument and dilating a diameter of the opening formed in the penis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and together with the description serve to explain principles of embodiments. Other embodiments and many of the intended advantages of embodiments will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. 
         FIG. 1  is an exploded perspective view of one embodiment of an instrument that is configured to prepare a penis for implantation of a penile prosthetic. 
         FIG. 2A  is a perspective view of one embodiment of a shaft of the instrument illustrated in  FIG. 1 . 
         FIG. 2B  is a cross-sectional view of the shaft illustrated in  FIG. 2A . 
         FIG. 3A  is a perspective view of one embodiment of a plunger of the instrument that is insertable into the shaft illustrated in  FIG. 2A . 
         FIG. 3B  is a cross-sectional view of a proximal end portion the plunger illustrated in  FIG. 3A . 
         FIG. 3C  is a cross-sectional view of a distal end portion of the plunger illustrated in  FIG. 3A . 
         FIG. 4A  is a side view of one embodiment of a dilation head that is attachable to the plunger illustrated in  FIG. 3A . 
         FIG. 4B  is an end view of the dilation head illustrated in  FIG. 4A . 
         FIG. 4C  is a cross-sectional view of the dilation head illustrated in  FIG. 4B . 
         FIG. 5A  is a cross-sectional view of the instrument illustrated in  FIG. 1 . 
         FIG. 5B  is a cross-sectional view of the instrument illustrated in  FIG. 5A  with the dilation head coupled to a distal end of the plunger. 
         FIG. 6  is an end view of the instrument illustrated in  FIG. 5B . 
         FIG. 7A  is a schematic view of one embodiment of a penis prepared for implantation of a penile prosthetic showing the instrument in a corpora measurement configuration and  FIG. 7B  is a cross-sectional view of the corpora of the penis. 
         FIGS. 8A and 8B  illustrate the instrument in dilation configurations with the dilation head moved to different locations along the shaft. 
         FIG. 9  is a cross-sectional view of one embodiment of an instrument system that is configured to measure and dilate an opening in a penis. 
         FIG. 10  is a cross-sectional view of one embodiment of an instrument including a dilation head threaded onto a distal end of a plunger. 
     
    
    
     DETAILED DESCRIPTION 
     In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. 
     It is to be understood that the features of the various exemplary embodiments described herein may be combined with each other, unless specifically noted otherwise. 
     The term “proximal” as employed in this application means that the referenced part is situated next to or near the point of attachment or origin or a central point: as located toward a center of the human body. The term “distal” as employed in this application means that the referenced part is situated away from the point of attachment or origin or the central point: as located away from the center of the human body. A distal end is the furthest endmost location of a distal portion of a thing being described, whereas a proximal end is the nearest endmost location of a proximal portion of the thing being described. For example, the glans penis is located distal, and of the crus of the penis is located proximal relative to the male body such that a distal end of a corpora cavernosum of the patient extends about midway into the glans penis. 
     Multiple different tools and instruments are employed in a typical penile prosthetic implantation procedure to form a recess sized to receive the implant. In general, the fewer tools employed during a body implant procedure, the better. 
     Embodiments provide an instrument configured to prepare a penis for implantation of a penile prosthetic, where the instrument includes a dilation head that is movable longitudinally along a shaft of the instrument. The dilation head is movable to a proximal end of the shaft such that the shaft has a substantially uniform diameter that is unobstructed and thus configured for measuring a length of the corpora cavernosum. The dilation head is configured to be reversibly movable along the length of the shaft to “core out” and/or dilate the corpora cavernosum. Thus, a single one of the instruments as described herein provides improved dilation of the corpora with improved procedural efficiency by performing the tasks of the multiple different tools and instruments typically employed in a penile prosthetic implantation procedure. 
       FIG. 1  is an exploded perspective view of one embodiment of an instrument  20  that is configured to prepare a penis for implantation of a penile prosthetic. The instrument  20  includes a shaft  22 , a plunger  24  that couples with and moves relative to the shaft  22 , and a dilation head  26  that couples with the plunger  24 . In one embodiment, the plunger  24  is inserted within the shaft  22  and the dilation head  26  is attached to the plunger  24  around the shaft  22 . Longitudinal movement of the plunger  24  relative to the shaft  22  moves the dilation head  26  longitudinally along the shaft  22 . 
     During use, as describe below, the plunger  24  is retracted proximally to draw the dilation head  26  toward a proximal end of the shaft  22 , which configures the shaft  22  for unobstructed insertion into a corpora cavernosa of the penis to allow the shaft  22  to measure the length of the corpora cavemosa. After the length measurement is taken, and while the shaft  22  is inserted into the corpora cavemosa, the plunger  24  is pushed proximally into the shaft  22  to pass the dilation head  26  along the shaft  22  in the distal direction. The movement of the dilation head  26  along the shaft  22  dilates the tissue in the corpora cavernosa. The dilation head  26  is removable from the shaft  22  and the plunger to allow other differently sized dilation heads  26  to be attached to the plunger  24  for selective dilation of the corpora. 
       FIG. 2A  is a perspective view and  FIG. 2B  is a cross-sectional view of one embodiment of the shaft  22 . In one embodiment, the shaft  22  has an exterior surface  30  that extends between a distal end  32  and a proximal end  34  and includes a first channel  36  and a second channel  38  that are formed in the exterior surface  30 . The exterior surface  30  defines an outside diameter of the shaft  22 , and in one embodiment the shaft  22  has a constant outside diameter that is suited for insertion into and measurement of a length of each corpora cavernosum. In one embodiment, the channels  36 ,  38  are open channels formed from a circular arc of greater than 180 degrees, where the first channel  36  is spaced a first distance H 1  apart from the second channel  38 . 
     In one embodiment, the shaft  22  is formed as a single monolithic shaft molded as a unit between the distal end  32  and the proximal end  34 , and a handle  40  is attached to the proximal end  34  of the shaft  22 . 
     In one embodiment, at least a portion of the exterior surface  30  of the shaft  22  is provided with indicia  42  placed at selected intervals, for example a series of markings spaced 1 cm apart, although other spacing is also acceptable. In one embodiment, the shaft  22  is fabricated from a circular rod to include the channels  36 ,  38  and a flat surface on which the indicia  42  are marked. In one embodiment, the indicia  42  are marked on the flat surface of the shaft  22  and over the exterior surface  30 . Marking the indicia  42  on the flat surface minimizes the deleterious effects of glare, which can occur in the typically brightly-lighted operating rooms. 
       FIG. 3A  is a perspective view and  FIGS. 3B and 3C  are cross-sectional views of one embodiment of the plunger  24 . In one embodiment, the plunger  24  extends between a distal end  52  and a proximal end  54  and includes a first rod  56  and a second rod  58  spaced apart from the first rod  56 , where the rods  56 ,  58  extend from a handle  60 . 
     The rods  56 ,  58  are sized to slide within the channels  36 ,  38  ( FIG. 2B ). For example, the rods  56 ,  58  are formed to have a diameter that is similar to or slightly less than the diameter of the channels  36 ,  38  (in order to allow for clearance between the rods  56 ,  58  and the channels  36 ,  38 ). In one embodiment, the first channel  36  and the second channel  38  are open channels such that at least a portion of the first rod  56  and the second rod  58  is visibly exposed through the exterior surface  30  of the shaft  22  ( FIG. 2B ) when the instrument  20  is assembled. 
     In one embodiment, the rods  56 ,  58  are flexible and pre-flexed or stressed such that the distal ends  52  deflect inwardly toward each other as illustrated by the distance H 2  in  FIG. 3C  showing the distal ends  52  are more narrowly spaced apart than the distance H 1  between the rods  56 ,  58  near the handle  60  ( FIG. 3B ). In particular, in one embodiment the rods  56 ,  58  are spaced by the first distance H 1  apart near the handle  60  as illustrated in the cross-sectional view of the proximal end portion of  FIG. 3B  and the distal ends  52  of the rods  56 ,  58  are tensioned (e.g., bent) to flex together such they are spaced apart by a distance H 2  that is less than the distance H 1  as illustrated in the cross-sectional view of the distal end portion of  FIG. 3C . In this manner, when the rods  56 ,  58  are engaged with the channels  36 ,  38  ( FIG. 2B ) the shaft  22  maintains the rods  56 ,  58  apart, one from the other, by the distance H 1 . Alternatively, when the distal ends  52  of the rods  56 ,  58  extend beyond the distal end  32  of the shaft  22  ( FIG. 2A ) the ends  52  are unconstrained and thus flex and pinch together a distance H 2  apart. 
     In one embodiment, the rods  56 ,  58  are formed to be substantially parallel with each other, for example as illustrated by the rods of plunger  134  in  FIG. 9 . 
       FIG. 4A  is a side view,  FIG. 4B  is an end view, and  FIG. 4C  is a cross-sectional view of the dilation head  26 . In one embodiment, the dilation head  26  includes an exterior surface  70  having an outside diameter of D 1  and an inside surface  72  that is formed to provide a recess  74 . The dilation head  26  is attachable to the distal ends  52  of the rods  56 ,  58  and its annular conformation is configured to be disposed over the shaft  22 . In one embodiment, the recess  74  is provided as an annular groove formed around the inside surface  72  of the dilation head  26 . 
     In one embodiment, the diameter D 1  is larger than the diameter of the shaft  22  ( FIG. 2B ) and the inside surface  72  of the dilation head  26  includes clearance notches  76  sized to move over the rods  56 ,  58  ( FIG. 3B ) of the assembled instrument  20 . In one embodiment, the dilation head  26  is removably attachable and re-attachable to the plunger  24  ( FIG. 3A ). Suitable examples of mechanisms that allow the dilation head to be removed from the plunger  24  include tension latches, threads, snap fits, friction fits, and quarter-turn quick attachment mechanisms (e.g., post-and-slot arrangements). 
     In one embodiment, the instrument  20  is configured to be reusable and is fabricated from a suitable material such as a polymer. Suitable polymers include polysulfone, polyetherimide, or polyester, or blends or derivatives of polysulfone, polyetherimide, or polyester. In one example, the shaft  22 , the plunger  24 , and the dilation head  26  are each fabricated from polysulfone and thus configured for disposable single surgical use. 
       FIG. 5A  is a cross-sectional view of the dilation head  26  disengaged from the plunger  24 . In one embodiment, the plunger  24  is longer than the shaft  22  such that the distal ends  52  of the rods  56 ,  58  extend beyond the distal end  32  of the shaft  22  when the handle  60  of the plunger  24  is in contact with a handle  40  of the shaft  22 . In one embodiment, the distal ends  52  of the rods  56 ,  58  combine to provide a tension latch  80 . The tension latch  80  is flexible and compresses to release from the dilation head  26  ( FIG. 5A ) and expands to engage with the dilation at  26  ( FIG. 5B ). 
     For example, in one embodiment the tension latch  80  includes a boss  82  that extends from an exterior surface of the each of the rods  56 ,  58 . The tension latch  80  is characterized in that the distal ends  52  of the rods  56 ,  58  deflect inwardly together when the ends  52  of the plunger  24  extend beyond the shaft  22 , which provides clearance for the bosses  82  to pass inside the interior surface  72  of the dilation at  26  for attachment/removal of head  26  from plunger  24 . For example, and with additional reference to  FIG. 3C , the distal ends  52  of the rods  56 ,  58  deflect inwardly to a spacing of approximately H 2 , which provides clearance for the bosses  82  to enter inside the interior surface  72  of the dilation head  26 . That is to say, the inside diameter of the inside surface  72  is about equal to the distance H 1  plus twice the diameter of one of the proximal portion of the rods  56 ,  58 . 
       FIG. 5B  is a cross-sectional view of the dilation head  26  attached to and engaged with the plunger  24 . When the dilation head  26  is placed over the compressed distal ends  52  of the rods  56 ,  58  ( FIG. 5A ) and the plunger  24  is retracted such that the ends  52  no longer extend beyond the shaft  22 , then the bosses  82  of the tension latch  80  are forced outward to engage with the recess  74  of the dilation head  26 . In this manner, a removable dilation head  26  is provided for the instrument  20 , which allows the surgeon to select differently sized dilation heads  26  to selectively dilate the corpora of the penis to a desired diameter, as described below. 
     The plunger  24  is movable longitudinally relative to the shaft  22 . Movement of the plunger  24  back and forth relative to the shaft  22  moves the dilation head  26  longitudinally back and forth along the shaft  22 . In one embodiment, the handle  40  attached to the shaft  22  is separated from the handle  60  attached to the plunger  24  when the distal ends  52  of the plunger  24  are located between the distal end  32  and a proximal end  30  of the shaft  22 . 
       FIG. 6  is an end view of the instrument  20 . The plunger  24  is engaged with the shaft and  22  such that the rods  56 ,  58  are engaged with the channels  36 ,  38  formed in the shaft  22 . The dilation head  26  is attached to the rods  56 ,  58  of the plunger  24  such that the dilation head  26  is disposed around the shaft  22 . 
       FIG. 7A  is a schematic view of one embodiment of a penis P prepared for implantation of a penile prosthetic showing the instrument  20   a  in a corpora measurement configuration and  FIG. 7B  is a cross-sectional view of the corpora C 1  and C 2  of the penis P. While the penile prosthetic is not shown, it would typically include a pair of inflatable cylinders, a reservoir, and a pump employed to transfer fluid to/from the reservoir, where the instrument  20  is employed to dilate the corpora for insertion of the cylinders. 
     The penis P is reclined against the torso such that the urethra U, surrounded by corpus spongiosum tissue, is oriented upward. The penis P has been incised to expose the corpora cavernosa (C 1  and C 2 ) and the instrument  20   a  has the dilation head  26  fully retracted proximally to allow the shaft  22  to measure the length of each of the corpora cavernosum (C 1  or C 2 ). In the corpora measurement configuration, the entire distal portion of the shaft  22  is unobstructed from the dilation head  26 . 
     The groin area  100  of the patient is shaved, cleaned and suitably prepped with a surgical solution prior to draping with a sterile drape as directed by the healthcare provider&#39;s procedures. A retraction device, such as a retractor  102  sold under the trademark Lone Star and available from Lone Star Medical Products of Stafford, Tex., is placed around the penis P if so desired by the surgeon to establish a surgically clean field. A catheter  103  is inserted into the urethra U from the distal end  104  of the penis P. Thereafter, the surgeon forms an incision to access the corpora cavernosa C 1  and C 2  of the penis. 
     Suitable examples of incisions include either an infrapubic incision or a transverse scrotal incision. The infrapubic incision is initiated between the umbilicus and the penis (i.e., above the penis), whereas the transverse scrotal incision is made across an upper portion of the patient&#39;s scrotum Sc. 
     As an example of the transverse scrotal approach, with reference to  FIG. 7B , the surgeon forms a 2-3 cm transverse incision through the subcutaneous tissue of the median raphe of the upper scrotum Sc and dissects down through the Darto&#39;s fascia Df and Buck&#39;s fascia Bf to expose the tunicae albuginea TA of the penis P. Thereafter, each corpora cavernosum C 1  and C 2  is exposed in a corporotomy where a small (approximately 1.5 cm) incision is formed to allow the surgeon to access and subsequently dilate the corpora cavernosa C 1  and C 2 . 
     With reference to both  FIGS. 7A and 7B , the surgeon typically will insert a blunt-ended scissors or other elongated tool to separate a portion of the spongiosum material to open a pathway for the instrument  20   a . The surgeon inserts the shaft  22  (instrument  20   a ) into the corpora cavernosa C 1  and C 2  to measure the proximal and distal length of each corpora cavernosum C 1  and C 2 . For example, the shaft  22  is inserted into one of the corpora cavernosa C 1  or C 2  forward in the distal penis toward the glans penis, the distal measurement is recorded by reading the indicia  42 , and the shaft  22  is inserted into the same corpora cavernosa C 1  or C 2  rearward in the proximal penis toward the crus of the penis to record the proximal length of the corpora by reading the indicia  42 . The distal and proximal measurements would typically be made in reference to a “stay stitch” temporarily placed in the incision. The sum of the distal and the proximal measurements represent the length of the corpora into which the implant is placed. This procedure is repeated for the other of the corpora cavernosa C 1  or C 2  to measure the length of the companion corpora. Thereafter, each corpora cavernosum C 1  and C 2  is dilated distally and proximally with the instrument  20 . 
       FIGS. 8A and 8B  illustrate the instrument  20  in the dilation configurations with the dilation head  26  moved midway along the shaft  22  ( FIG. 8A ) and the dilation head  26  moved to the distal end of the shaft ( FIG. 8B ). In one exemplary approach, the surgeon begins dilation of the distal and proximal corpora cavernosum C 1  and C 2  by introducing a dilation head  26  having an 8 mm outside diameter (D 1  in  FIG. 4A ) into the spongy tissue of one of the corpora C 1  or C 2 . The plunger  24  is moved into the shaft  22  to move the dilation head  26  from a proximal location (instrument  20   a  in  FIG. 7A ) to a distal location (instrument  20   c ) to open the spongy tissue of the corpora along the length of the penis P. The plunger  24  is withdrawn proximally with the shaft  22  remaining in the penis P, and if the surgeon determines it to be desirable, once again advances the dilation head  26  distally and longitudinally along the shaft  22  to fully dilate the tissue of the corpora. Thereafter, the surgeon may optionally remove the instrument  20  from the penis P, remove the 8 mm dilation head, for example, and attach a larger diameter dilation head  26  to the plunger  24 , and insert the newly configured tool  20  into the penis P to sequentially dilate the corpora cavernosum C 1  and C 2  to a width that accommodates the selected cylinder diameter of the implant. 
     In another exemplary approach, the surgeon may choose to dilate the distal and proximal corpora by a single introduction of a dilation head having a 14 mm outside diameter. Alternatively, the surgeon may choose to sequentially dilate the corpora with a series of dilation heads  26  having an outside diameter ranging from 8 mm to 10 mm to 12 mm and outward to 14 mm in diameter, in the manner described above. Other dilation heads  26  wider than 14 mm are also within the scope of this disclosure. In any regard, the dilation head  26  is introduced and pushed distally toward the glans penis and proximally toward the crus of the penis to dilate each of the corpora cavernosum C 1  and C 2  along its length. After dilation of the corpora cavernosum C 1  and C 2 , the surgeon selects a proper length of implant and proceeds with placement of cylinders of the implant within the fully dilated corpora. 
       FIG. 9  is a cross-sectional view of an instrument system  120  including a set  122  of dilation heads  26 , each removably attachable to the tension latch  80  of the plunger  24 . In one embodiment, the set  122  of dilation heads includes multiple dilation heads  26   a ,  26   b ,  26   c  each having a different diameter, where each dilation head  26   a ,  26   b ,  26   c  is configured to couple to the distal ends  52  of the plunger  24 . 
     In one embodiment, the instrument  20  ( FIG. 1 ) and the set  122  of dilation heads are provided as a kit of parts. In one embodiment, dilation head  26   a  is provided with an outside diameter D 1 , dilation head  26   b  is provided with an outside diameter D 2 , and dilation head  26   c  is provided with an outside diameter D 3 , where D 3  is greater than D 2 , and D 2  is greater than D 1 . As an example, in one embodiment the diameter D 1  is about 8 mm, the diameter D 2  is about 10 mm, and a diameter D 3  is about 12 mm. It is to be understood that the set  122  of dilation heads  26  could be provided with diameters ranging from 6 mm to 18 mm or more, in increments of about 2 mm, for example, depending upon the patient size or surgeon preference. 
     Each of the dilation heads  26   a ,  26   b ,  26   c  is provided with a recess  74  that is configured to couple with the bosses  82  of the tension latch  80 . During use, the surgeon would initially measure the length of the corpora cavernosa C 1  and C 2  with the shaft  22 , dilate the distal and proximal corpora cavernosa C 1  and C 2  ( FIG. 7B ) in the range of D 1  with the dilation head  26   a , remove the dilation head  26   a  and attach the larger diameter D 2  of the dilation head  26   b  to the plunger  24 , dilate the distal and proximal corpora cavernosa C 1  and C 2  in the range of D 2 , and remove the dilation head  26   b  and attach the even larger diameter of the dilation head  26   c  to the plunger  24  to sequentially and fully dilate the distal and proximal corpora cavernosa C 1  and C 2  of the penis P in the range of D 3 . 
       FIG. 10  is a cross-sectional view of one embodiment of an instrument  130  that is configured to prepare a penis for implantation of a penile prosthetic and including a dilation head  136  threaded onto a distal end of a plunger  134 . The instrument  130  includes a shaft  132  that supports the plunger  134  in a manner similar to that described above for instrument  20 . In one embodiment, the distal end of the plunger  134  is threaded to receive threads formed on an inside surface of the dilation head  136 . In this manner, the dilation head  136  is removable from the distal end of the plunger  134  in a twist-on and twist-off approach. As described above in  FIG. 8 , one embodiment of instrument  130  includes a set of dilation heads, where each dilation head is removably attachable to the plunger  134  to allow the surgeon to sequentially dilate the corpora cavernosa to an increasingly larger diameter. 
     Embodiments provide an instrument that is configured to prepare a penis for implantation of a penile prosthetic, where the instrument includes a shaft suited for measuring a length of the corpora cavernosum and a dilation head that is movable longitudinally along the shaft of the instrument to dilate the corpora cavernosum. Thus, a single instrument is provided that has improved cost effectiveness and procedural efficiency over the prior tools, and is suited to measure and dilate the corpora cavernosum of the penis. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of medical devices as discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.