Abstract:
A method of implanting a penile prosthesis into a patient includes engaging a cap that is attached to a cylinder of the penile prosthesis with a distal end of a tool, and cradling the cylinder of the penile prosthesis between two support arms of the tool. The method additionally includes inserting the two support arms of the tool and the cylinder secured between the two support arms into a corpora cavernosum of the patient.

Description:
BACKGROUND 
     Implanted penile prostheses provide relief for men with erectile dysfunction. 
     In a typical implantation procedure, the penis of the patient is incised to expose a pair of corpora cavernosa that are aligned axially in a side-by-side orientation within the penis. Each corpora cavernosum is dilated, for example by introducing gradually larger stainless steel rods into the corpora cavernosum until a space is created that is sized to receive a cylinder of the penile prosthesis. The cylinder is typically provided with a traction suture attached to its distal end. A tool (e.g., a “Furlow” introducer) is introduced into the space formed in the corpora cavernosum to guide a needle (e.g., a “Keith” needle) attached to the traction suture through a distal surface of the glans penis. The needle and the suture are subsequently passed through the glans penis to pull the cylinder of the penile prosthesis to a distal location within the corpora cavernosum, which locates the distal end of the prosthesis approximately mid-glans. Although the above-described approach has proven effective in treating erectile dysfunction, the needle forms a lesion in the glans penis, which can cause bleeding and discomfort to the patient. 
     SUMMARY 
     One aspect provides a cap configured to be attached to a cylinder of an implantable penile prosthesis. The cap includes a body section and a tip section. The body section defines a recess that is attachable to an end of the cylinder of the implantable penile prosthesis and the tip section terminates in a tip having a curved exterior surface. The tip section defines at least one slot formed therein that extends away from the body section and has a slot axis that intersects with a longitudinal axis of the cap. 
     One aspect provides a method of implanting a penile prosthesis into a patient. The method includes engaging a cap that is attached to a cylinder of the penile prosthesis with a distal end of a tool, and cradling the cylinder of the penile prosthesis between two support arms of the tool. The method additionally includes inserting the two support arms of the tool and the cylinder secured between the two support arms into a corpora cavernosum of the patient. 
    
    
     
       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 a perspective view of a system including a tool configured to implant a penile prosthesis assembly according to one embodiment. 
         FIG. 2  is an exploded side view of the penile prosthesis assembly illustrated in  FIG. 1 . 
         FIG. 3  is a perspective view of the tool illustrated in  FIG. 1 . 
         FIG. 4  is a top view of the tool illustrated in  FIG. 1 . 
         FIG. 5  is a cross-sectional view of taken through a distal end of the tool as illustrated in  FIG. 4 . 
         FIG. 6  is an expanded top view of the distal end of the tool illustrated in  FIG. 4 . 
         FIG. 7  is a perspective view of a cap attachable to a cylinder of a penile prosthesis according to one embodiment. 
         FIG. 8  is a side view of the cap illustrated in  FIG. 7 . 
         FIG. 9  is a cross-sectional view of the cap illustrated in  FIG. 8 , where the cross-sectional view is rotated by 180 degrees relative to the orientation of  FIG. 8 . 
         FIG. 10A  is an expanded cross-sectional view of a distal end of the cap illustrated in  FIG. 9 . 
         FIG. 10B  is an expanded cross-sectional view of another embodiment of a cap. 
         FIG. 11  is a side view of the system illustrated in  FIG. 1  including the tool engaged with the penile prosthesis assembly. 
         FIG. 12  is a top view of a patient prepped for the surgical implantation of the penile prosthesis assembly illustrated in  FIG. 11 . 
         FIG. 13  is a top view of the patient with the penile prosthesis assembly inserted distally into one corpora cavernosum of the penis according to one embodiment. 
         FIG. 14A  is a side view of the penile prosthesis assembly including a proximal rear tip cap having a slot sized to receive the tool illustrated in  FIG. 3 . 
         FIG. 14B  is a perspective view of the tool illustrated in  FIG. 3  attached to the rear tip cap of the penile prosthesis assembly illustrated in  FIG. 14A . 
         FIG. 14C  is a perspective view of the penile prosthesis assembly illustrated in  FIG. 1  and another embodiment of a tool configured to implant assembly into one of the corpora cavernosa of the patient. 
         FIG. 15  is a side view of a rear tip extender attachable to the penile prosthesis assembly illustrated in  FIG. 2  according to one embodiment. 
     
    
    
     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. 
     Soft tissue includes dermal tissue, sub-dermal tissue, ligaments, tendons, or membranes but does not include bone. 
     The term “proximal” as employed in this application means that part that 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 part that 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 and the bulb of the penis are both located proximal relative to the male body. 
     An acute angle is defined to be an angle of less than 90°. At orthogonal angle is a right angle, which is an angle of 90°. Thus, an acute angle is not a right angle. 
     A sutureless penile prosthesis is a penile prosthesis that is characterized by an absence of a suture hole formed in a distal end of the prosthesis. Conventional penile prostheses have a suture attached to a suture hole formed in a distal end of the prosthesis, where the suture is configured to be passed through the glans penis to assist in inserting the prosthesis distally into the corpora cavernosum. In contrast, the sutureless penile prosthesis described herein has no suture hole and is configured to be inserted into a distal end of the corpora cavernosum without passing a suture or a needle through the glans penis. 
     Embodiments provide an implantable penile prosthesis assembly including a sutureless cylinder that is configured to be implanted into a patient. The assembly includes a cap having a tip section that defines at least one and preferably two slots that converge toward a distal end of the cap. In one embodiment, a tool is provided having converging distal end portions, where each converging distal end portion is configured to engage a respective one of the slots formed in the cap. The tool is configured to retain the prosthetic cylinder between a pair of spaced apart arms. The converging slots, in combination with the converging distal end portions of the tool, provide an engagement mechanism that enables the tool to insert the penile prosthesis cylinder into a distal end of the corpora of a penis of the patient without employing sutures. 
       FIG. 1  is a perspective view of a system  20  for implanting a penile prosthesis according to one embodiment. System  20  includes an implantable penile prosthesis assembly  22  and a tool  24  configured to implant assembly  22  into one of the corpora cavernosa of the patient. In one embodiment, assembly  22  includes an inflatable cylinder  26 , a distal end cap  28 , and a proximal end cap  30  (or rear tip extender  30 ). Tool  24  is configured to engage with one or both of the end caps  28 , individually to facilitate implanting assembly  22  into the patient without the use of a suture as commonly employed to pull a conventional cylinder toward a distal end of the corpora cavernosum. 
       FIG. 2  is an exploded side view of the penile prosthesis assembly  22 . The inflatable cylinder  26  is generally provided as an oblong cylinder that is closed at distal end  32  and closed at proximal end  34  when proximal end cap  30  is attached. When so assembled, cylinder  26  is sealed and configured to be inflated when a fluid (e.g., saline typically, or a gas) is introduced into tubing  36 . 
     In one embodiment, inflatable cylinder  26  is fabricated from a urethane material sold under the trademark Bioflex and is available from Coloplast Corp., Minneapolis, Minn. In one embodiment, distal end  32  of cylinder  26  is dipped in urethane material that cures to provide a desirable leading-end shape to cylinder  26 , where the distal end  32  of cylinder  26  includes a step such that end cap  28  smoothly blends to with distal end  32  when attached to distal end  32 . In one embodiment, distal end cap  28  is formed from silicone, which is dissimilar to the urethane material of the Bioflex cylinder  26 . To facilitate the attachment of these two dissimilar materials, in one embodiment the urethane material of cylinder  26  is coated with fumed silica to prepare the urethane surface for bonding with the silicone cap  28 . 
     One or both of distal end cap  28  and proximal end cap  30  are formed to include slots  38 ,  40 , respectively, that converge inwardly into the cap and are sized to receive pincer ends of tool  24 , which enables the sutureless implantation of assembly  22 . 
       FIG. 3  is a perspective view of the tool  24 . In one embodiment, tool  24  includes a handle  50  having a spine  52 , first and second tongs  54 ,  56  extending from spine  52 , and first and second arms  64 ,  66  extending from tongs  54 ,  56 , respectively. Arms  64 ,  66  terminate at a pair of opposing and converging distal ends  65 ,  67 , respectively. In one embodiment, tool  24  is formed from metal or plastic such that spine  52  provides tongs  54 ,  56  with a spring constant that enables arms  64 ,  66  to function as spring forceps. One suitable material for fabricating tool  24  includes, for example, a 22 gauge stainless steel (about 0.029 inches thick) that is electro-polished. 
     In one embodiment, arms  64 ,  66  are generally straight and extend along a major axis A of tool  24  that is disposed relative to handle  50  by an angle B. In one embodiment, angle B is in the range of 5-45° such that handled  50  is angled relative to arms  64 ,  66 . Arms  64 ,  66  may be parallel or non-parallel relative to each other. 
     In one embodiment, at least one of the arms  64 ,  66  includes gradient markings  70  initiated at one of the distal ends  65 ,  67  and extend proximally to a location where arms  64 ,  66  attach to tongs  54 ,  56 , respectively. The gradient markings  70  are configured to enable a surgeon to measure a depth of a dilated corpora cavernosum as the arms  64 ,  66  are inserted distally or proximally into the dilated corpora. In one embodiment, gradient markings  70  range between 0-16 cm, although other ranges for gradient markings  70  are also acceptable. 
     In one embodiment, each arm  64 ,  66  is formed to include a plurality of through-holes  72  oriented in a row. The through-holes  72  are configured to receive one or more fixation devices that are employed to immobilize the arms  64 ,  66  relative to a surface in the surgical field. Typically, the surgeon will attach one end of a fixation device (not shown, but see  FIG. 13 ) to one of the through-holes  72  on one of the arms  64 ,  66  and another end of the fixation device to the surgical field to stabilize or otherwise hold tool  24  in place. 
       FIG. 4  is a top view and  FIG. 5  is a cross-sectional view of tool  24 . Tool  24  is configured to function as a spring forceps, in which arms  64 ,  66  are substantially parallel (or diverge slightly) to accommodate the placement of cylinder  26  ( FIG. 2 ) on major axis A between arms  64 ,  66 . Distal ends  65 ,  67  converge together in the form of pincers. 
       FIG. 5  is a cross-sectional view of tool  24  taken along line of  5 - 5  of  FIG. 4  and illustrates one embodiment in which an inside surface  74  of a distal portion of arm  64  and an inside surface  76  of a distal portion of arm  66  are each curved to define a portion of an arc. During insertion of assembly  22  ( FIG. 2 ), cylinder  26  is deflated to provide a “pancake-shaped” flattened cylinder. The straight, flat inside surfaces of arms  64 ,  66  mate against the flattened walls of cylinder  26 . Cap  28  is attached to cylinder  26  and generally retains its conical shape. To this end, inside surfaces  74 ,  76  of arms  64 ,  66  curve to complement an exterior surface of cap  28  ( FIG. 2 ), which enables the flat proximal portion of arms  64 ,  66  to cradle the flattened cylinder  26  and the concave inside surfaces  74 ,  76  of arms  64 ,  66  to cradle cap  28  during insertion of assembly  22  ( FIG. 2 ). 
       FIG. 6  is an expanded top view of converging distal ends  65 ,  67  of tool  24 . The major axis A of tool  24  ( FIG. 3 ) is disposed on a centerline of tool  24  located between arms  64 ,  66 . Generally, each distal end  65 ,  67  is formed to converge toward the centerline of tool  24 . In one embodiment described with reference to converging distal end  67 , each converging distal end portion is formed from a series of sections that gradually converge to a greater degree toward major axis A. For example, converging distal end  67  is formed from a first section  80  extending from arm  66  toward axis A, a second section  82  extending from first section  80  toward axis A, and a third section  84  extending from second section  82  toward axis A. In one embodiment, first section  80  is substantially linear relative to arm  66 ; second section  82  is angled by about 5-15° to converge toward major axis A; and third section  84  is angled by about 20-45° to further converge toward major axis A. In one embodiment, the series of gradually converging sections combine to deflect ends  65 ,  67  into pincers that have an included angle P that complements an angle of convergence for slots  38  into which ends  65 ,  67  are inserted. 
     Converging distal end  65  is likewise configured in a similar matter. Consequently, converging distal ends  65 ,  67  converge toward the centerline of major axis A such that ends  65 ,  67  are closely spaced apart, or alternatively, ends  65 ,  67  pinch together and touch. 
     In one embodiment, each section  80 ,  82 ,  84  extends for a length of between about 0.2-0.4 inches such that converging distal ends  65 ,  67  have a total length of between about 0.6-1.2 inches. 
       FIG. 7  is a perspective view and  FIG. 8  is a side view of cap  28 . In one embodiment, cap  28  includes a body section  90  and a tip of section  92 , where the body section  90  defines a recess  94  that is sized to be attached over distal end  32  of cylinder  26  ( FIG. 2 ). Body section  90  is formed as a hollow cone-shaped sleeve around recess  94  that is generally flexible and conformable to fit over distal end  32  of cylinder  26 . Tip section  92  is formed or molded to be solid. In one embodiment, cap  28  is molded from silicone, although other suitable materials are also acceptable. 
     In one embodiment, tip section  92  provides a curved exterior surface and includes one or more slots  38  formed at least partially within tip section  92 . For example, in one embodiment slot  38  extends from a slot opening  96  formed in body section  90  and terminates in a slot end  98  that is formed in tip section  92 . 
     In another embodiment, tip section  92  provides a curved exterior surface and slots  38  extend from a slot opening  96  formed in tip section  92  and terminate in a slot end  98  also formed in tip section  92 . 
     The slot  38  generally converges toward a center of a distal end of tip section  92  and forms a pocket that receives one of the converging ends  65 ,  67  of tool  24  ( FIG. 4 ). In one embodiment best illustrated in  FIG. 8 , the slot opening  96  is oriented on a lateral axis as illustrated that is substantially orthogonal to the longitudinal axis C ( FIG. 9 ), and slot  38  is formed as a tapered slot with the slot opening  96  having a lateral dimension W 1  along the lateral axis that is wider than a width W 2  of the slot end. Thus, slots  38  taper laterally between slot opening  96  having a width W 1  and slot end  98  having a width W 2 , where width W 1  is greater than width W 2 . In one embodiment, slot opening  96  extends radially about 90 degrees or more around a circumference of cap  28 , such that opening  96  extends approximately 25% around the circumference of cap  28 . 
       FIG. 9  is a cross-sectional view of cap  28 . In one embodiment, cap  28  has a length L and recess  94  extends a majority of length L along a central longitudinal axis C of cap  28 . The slots  38  are configured to enable the placement of cap  28  and cylinder  26  ( FIG. 2 ) in a sutureless manner within the patient. However, some surgeons desire to have the option of placing the prosthesis distally within the penis via a suture that is employed to guide cylinder  26  distally forward within the penis. With this in mind, in one embodiment an optional suture hole  99  is formed horizontally between slots  38  and extends through tip section  92  to enable the surgeon to place the prosthesis in a manner that s/he has become accustomed to should the surgeon opt not to employ tool  24 . 
     The central longitudinal axis C longitudinally bisects cap  28  as illustrated in  FIG. 9 . In one embodiment, each slot  38  extends away from body section  90  and has a slot axis S that intersects with central axis C of cap  28  in an acute angle P. In one embodiment, the angle P ranges between approximately 25-45°, with one suitable example of converging angle P being about 36°. In one embodiment, a first slot  38  is offset from a second slot  38  by 180 degrees, where each slot  38  has an axis S that intersects with the central axis C of cap  28  in an acute angle 
       FIG. 10A  is an expanded cross-sectional view of tip section  92  of cap  28 . In one embodiment, slot  38  is provided with a slot opening  96  having a gap size of approximately 0.005-0.010 inches and slot end  98  is located about 0.015-0.030 inches away from opening  96  (i.e., slot  38  has a length of about 0.015-0.030 inches). Slot  38  is suitably provided as a straight slot where slot end  98  has a gap size approximately equal to the gap size of slot opening  96 . Alternatively, slot end  98  has a gap size that is greater than the gap size of slot opening  96 . 
       FIG. 10B  is an expanded cross-sectional view of another embodiment of a cap  28 ′. Cap  28 ′ includes a body section  100  having an outer surface  102  and a flap  104  extending from outer surface  102  to form a slot  105  extending from a slot opening  106  to a slot end  108 . Ends  65 ,  67  of tool  24  ( FIG. 3 ) are configured to slide under flap  104  and engage within slots  105  to facilitate implanting cap  28 ′ and cylinder  26  ( FIG. 2 ). In one embodiment, cap  28 ′ is formed from silicone and flaps  104  are configured to lay flat when tool  24  is withdrawn from slots  105 . 
       FIG. 11  is a side view of system  20  including tool  24  engaged with penile prosthesis assembly  22 . In preparation for the implantation procedure, a syringe or other suitable suction device is coupled to tubing  36  to evacuate and, collapse cylinder  26 . Distal ends  65 ,  67  (one shown) of arms  64 ,  66  are inserted into slots  38  of cap  28 . Handle  50  extends away from the major axis of cylinder  26  to provide clearance that enables improved access into a dilated corpora cavernosum of the patient, as described below. 
       FIG. 12  is a top view of the patient prepped and ready for implantation of a pair of the inflatable penile prosthesis assemblies  22  (one of which is illustrated), and  FIG. 13  is a top view of the patient having one inflatable penile prosthesis assembly  22  inserted distally into one of the pair of copora cavernosa of the patient. The following description of  FIGS. 12 and 13  refers to  FIG. 2  (assembly  22 ),  FIG. 3  (tool  24 ), and  FIG. 9  (cap  28 ). 
     The groin area  120  of the patient is cleaned, shaved, and suitably prepped with, for example, a surgical solution prior to draping with a sterile drape. A retraction device, such as a retractor  122  sold under the trademark Lone Star and available from Lone Star Medical Products of Stafford, Tex., is placed around the penis P. Thereafter, the surgeon forms an incision to access the corpora covernosum of the patient, where 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, 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 Dartos fascia and Buck&#39;s fascia to expose the tunicae albuginea of the penis P. Thereafter, each corpora cavernosum is exposed in a corporotomy where a small (approximately 1.5 cm) incision is formed to enable the surgeon to access and dilate the corpora cavernosum. The corpora cavernosum is dilated distally and proximally with a suitable expanding tool to create a space for cylinder  26 . For example, the surgeon begins dilation of both the distal and proximal corpora cavernosum by introducing an 8 mm dilator into the spongy tissue of the corpora with sequential progression to about a 14 mm dilator, each of which are introduced and pushed distally toward the glans penis and the crus of the penis, respectively. In one embodiment, after dilation of the corpora cavernosum, the surgeon employees the gradient markings  70  of tool  24  to measure a length of the dilated corpora cavernosum, which facilitates selection of the proper length of assembly  22  (e.g., cylinder  26  and ends  28 ,  30 ) for implantation. In one embodiment, the surgeon employees tool  24  to at least partially (or further) dilate the corpora cavernosum. 
     After dilation of a first of the corpora cavernosa, the primed and deflated sutureless cylinder  26  is inserted through the corporotomy with tool  24 . As regards distal placement, for example, the cap  28  is introduced into the dilated corpora cavernosum through the corporotomy and the surgeon employs handle  50  to push the ends  65 ,  67  of insertion tool  24  distally to direct cylinder  26  to the distal-most portion of the corpora cavernosum. The surgeon may palpate the end of penis P at the subcoronal area  124  to locate the distal end of cap  28  to ensure proper placement of penile prosthesis assembly  22  interior to a corona of glans penis of the patient. Notably, the sutureless cylinder  26  is thus located in the distal-most and portion of the corpora cavernosa without the use of a suture threaded through the glans penis. 
     The proximal end  30  of the penile prosthesis assembly  22  is implanted into the proximal corpora cavernosum, which is typically completed after implantation of the distal end of assembly  22  (the order of implantation is based on surgeon preference). To facilitate placement of the proximal end  30  of the sutureless penile prosthesis assembly  22 , tool  24  is provided with apertures  72  formed in arms  64 ,  66  ( FIG. 3 ) that enable the surgeon to stabilize the inserted tool  24  relative to retractor  122 . For example, a tie-down or other fixation device is attached between aperture  72  and retractor  122  as illustrated in  FIG. 13  such that tool  24  and the distal end of assembly  22  is held in place within the distal end of the corpora cavernosum, which maintains the proper insertion orientation of cylinder  26  within the distal corpora cavernosum. The stabilization of the distal end of assembly  22  is useful in properly placing the proximal end  30  of penile prosthesis assembly  22  into the proximal corpora cavernosa. 
       FIG. 14A  is a side view of penile prosthesis assembly  22  including proximal end  30  provided with slot  40 . Proximal end cap  30  includes a recess that is attachable to the proximal end  34  of cylinder  26  and is configured for implantation proximally toward a crus of the penis P.  FIG. 14B  is a perspective view of a separate or second tool  24  engaged with slot  40  and readied for insertion of proximal end tip  30  into the proximal corpora cavernosum (the proximal corpora cavernosum is dilated with dilation introducers in a manner similar to the dilation of the distal corpora cavernosa as described above). In one embodiment, distal ends  65 ,  67  are each engaged with one of the slots  40  such that arms  64 ,  66  cradle cylinder  26  and handle is available to direct the proximal end tip  30  into the proximal corpora cavernosum toward a crus of the penis P. 
     After insertion of proximal end tip  30  into the proximal corpora cavernosum, tool  24  is removed from assembly  22  leaving proximal end tip inserted in the proximal corpora cavernosum. Thereafter, the fixation devices are removed from between apertures  72  and retractor  122  and tool  24  is removed from cap  28  leaving cylinder  26  inserted into the distal corpora cavernosum. The corporotomy is closed, and the remaining portions, for example a reservoir and/or a pump, are implanted in the abdomen and scrotum Sc, respectively, of the patient. 
       FIG. 14C  is a perspective view of implantable penile prosthesis assembly  22  and another embodiment of a tool  24 ′ configured to implant assembly  22  into one of the corpora cavernosa of the patient. The inflatable cylinder  26 , distal end cap  28 , and proximal end cap  30  (or rear tip extender  30 ) are each substantially as described above. In one embodiment, tool  24 ′ is provided as a single linear arm implement that is configured to engage with one or both of the end caps  28 ,  30  individually to facilitate implanting assembly  22  into the patient without the use of a suture as commonly employed to pull a conventional cylinder toward a distal end of the corpora cavernosum. Tool  24 ′ includes one linear arm  150  having a distal end  152  that is curved or angled out of the plane of arm  150 . To this end, distal end  152  of arm  150  is configured to engage with slot  38  of distal tip  28  or slot  40  of proximal tip to gain traction for insertion of the implant. In particular, the angled or converging nature of slots  38 ,  40  provide tool  24 ′ with traction for insertion of assembly  22 . In addition, the linear conformation of tool  24 ′ is configured to provide low friction removal of tool  24 ′ after implantation of assembly  22 . 
       FIG. 15  is a side view of a rear tip extender  130  attachable to penile prosthesis assembly  22  according to one embodiment. Rear tip extenders are sometimes attached to assembly  22  to increase the length of the assembly. Slot  40  formed in proximal end cap  30  is still available to receive tool  24  even after rear tip extender  130  is attached to assembly  22 . However, in this optional embodiment rear tip extender  130  is attachable to proximal end  30  of assembly  22  and includes at least one slot  140  that is also configured to receive tool  24 . Slot  140  is similar to slot  38  ( FIG. 9 ) or slot  40  ( FIGS. 2 and 14A ) and is configured to engage with distal ends  65 ,  67  ( FIG. 3 ) of tool  24  to enable tool  24  to insert proximal end of assembly  22  into a proximal corpora cavernosum of the patient. For example, in one embodiment rear tip extender  130  is a cap having a recess  142  formed in its body section and is sized to be attachable to proximal end  30  of cylinder  26  for implantation proximally toward a crus of the penis P ( FIG. 12 ). Depending upon the size of the patient, and upon surgeon preference, the procedure may indicate that the selected size of assembly  22  is less than entirely optimal. In such a case, the surgeon may desire to add length to assembly  22  by attaching rear tip extender  130  to proximal end  30  of cylinder  26 . Slot  140  in rear tip extender  130  enables the sutureless insertion of assembly  22 /extender  130  in a manner similar to that described above in reference to  FIGS. 14A and 14B . 
     Embodiments of a cap attachable to an implantable penile prosthesis, an assembly, and a system for implanting such an assembly have been described. The cap provides converging slots that engage with converging distal ends of the tool to provide an engagement mechanism that enables insertion of penile prostheses into corpora of a penis without employing guide sutures in the glans 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.