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ORIGINAL RESEARCH—SURGERY A Guide for Inflatable Penile Prosthesis Reservoir Placement: Pertinent Anatomical Measurements of the Retropubic Space Gerard Henry, MD,* Wayland Hsaio, MD,† Edward Karpman, MD,‡ Anthony T. Bella, MD,§ Rafael Carrion, MD,¶ Leroy Jones, MD,** Brian Christine, MD,†† Elizabeth Eisenhart, JD,* Mario A. Cleves, PhD,‡‡ and Andrew Kramer, MD§§ *Regional Urology, Shreveport, LA, USA; †Department of Urology, Men’s Health Center, Emory University, Atlanta, GA, USA; ‡El Camino Urology Medical Group, Inc., Mountain View, CA, USA; §Department of Surgery, University of Ottawa, Ottawa, ON, Canada; ¶Department of Urology, USF College of Medicine, Tampa, FL, USA; **San Antonio Urology, San Antonio, TX, USA; ††Erectile Restoration and Prosthetic Urology, Urology Centers of Alabama, Birmingham, AL, USA; ‡‡ Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, AR, USA; §§Department of Urology, University of Maryland School of Medicine, Baltimore, MD, USA DOI: 10.1111/jsm.12361

ABSTRACT

Introduction. The primary concern for many prosthetic urologic surgeons in placing the three-piece inflatable penile prosthesis (IPP) is the concept of “blind reservoir placement.” Extensive reports permeate the literature regarding bladder, bowel, vascular, and various hernial complications occurring while attempting to place the reservoir into the retropubic space. However, despite these widely documented complications, there is a paucity of published literature on surgically pertinent anatomical measurements of the retropubic space relating to reservoir placement. The focus of this project was to evaluate the special relationships and anatomical measurements of the retropubic space to better aid the surgeon in the safe placement of the reservoir. Aim. Analyses of the spatial measurements of reservoir placement into the retropubic space with a focus on utilizing a penoscrotal approach were conducted. In addition, we reviewed and evaluated the published literature for important contributions surrounding the various surgical techniques during placement of a penile prosthesis reservoir. Methods. Cadaveric pelvic specimens were dissected to determine the distance and angulation (in degrees) from the inguinal ring to several critical anatomic structures in the pelvis. This format was utilized to simulate the basic features of reservoir placement into the classic retropubic space. We also reviewed and evaluated the published literature for important contributions describing the various surgical techniques in the placement of penile prosthesis reservoirs into the retropubic space. Main Outcome Measures. Anatomic measurements were obtained from the inguinal ring to the bladder, external iliac vein, and superior origin of the dorsal suspensory ligament at the anterior apex of the pendulous penis. The angle was measured from the inguinal ring to these structures and recorded. We also reviewed the published literature for various penoscrotal IPP surgical techniques involving placement of the reservoir into the retropubic space to further supplement the pertinent spatial relationships data acquired in this study. Results. Of the 28 cadavers, 3 were excluded because of signs of major pelvic surgery, and an additional 6 sides were excluded because of unilateral fibrosis/surgery or difficulty in exposure. Distance to the decompressed bladder was 5–8 cm (average 6.45 cm) at a 15–30 (22.8) degrees medial measurement from the inguinal ring. The filled bladder was 2–4 cm (average 2.61 cm) from the inguinal ring. The external iliac vein distance from the inguinal ring was 2.5–4 cm (average 3.23 cm) at a 20–60 (36.4) degrees lateral measurement from the inguinal ring. Heretofore, the published literature does not appear to have detailed measurements that are provided in this study. Conclusions. These anatomical measurements of the retropubic space demonstrate the importance of decompressing the bladder and avoiding deep dissection lateral to the inguinal ring, as the external iliac vein is much closer than currently espoused. We feel that these data are significant to the surgeon proceeding with reservoir placement during

© 2013 International Society for Sexual Medicine

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Henry et al.

IPP surgery. Henry G, Hsaio W, Karpman E, Bella AT, Carrion R, Jones L, Christine B, Eisenhart E, Cleves MA, and Kramer A. A guide for inflatable penile prosthesis reservoir placement: Pertinent anatomical measurements of the retropubic space. J Sex Med 2014;11:273–278. Key Words. Penile Prosthesis; Penis; Surgery; Anatomy

Introduction

B

lind reservoir placement is widely considered the bane of the penoscrotal approach to inflatable penile prostheses (IPPs). Extensive reports in the literature abound describing bladder, bowel, vascular, and different types of hernia complications occurring while attempting to place the reservoir into the retropubic space [1–9]. However, despite these widely documented complications, there appears to be no published literature on the important anatomical measurements of the retropubic space relating to reservoir placement. In fact, many urologists compromise the implant models they offer patients because of their inability to perform this step of the procedure. Furthermore, the existing published literature on surgical placement of the reservoir into the retropubic space does not offer a careful, clearly descriptive, step-by-step guide for inexperienced prosthetic urologists [10–12]. Nor does the existing literature provide detailed measurements that may assist the placement of the reservoir into the retropubic space. We evaluated the pertinent anatomical measurements of the retropubic space to better aid in the safe placement of the reservoir.

Methods

A group of high volume prosthetic surgeons with extensive publication histories on reservoir placement and related complications critically appraised these data. Specifically, this group focused on pertinent anatomical measurements of the retropubic space to assist in placement of the reservoir during implantation of three-piece IPP with special emphasis on surgical safety. A review of the published literature using PubMed line searches was conducted (search terms used “penile prosthesis reservoir complications,” “penile prosthesis reservoir complication,” and “penile prosthesis complication hernia” searched on July 29, 2013) with emphasis on complications involved with placement of the reservoir into the retropubic space. A total of 22 cadaver bodies in 5 different surgical training courses and at 2 locations were used J Sex Med 2014;11:273–278

for a total of 44 possible sides. Cadaveric dissection was performed, and measurements were done by a group of six experienced prosthetic urologists. In addition, an independent, seventh prosthetic urologist at a large university anatomy lab evaluated 6 bodies for possible 12 sides. A total of 56 sides were evaluated. Exclusion criteria included any signs of surgery/fibrosis in the pertinent anatomic areas or difficulty in exposure. All measurements were taken from the ipsilateral inguinal ring at the point nearest to the pubic bone and to the nearest point of the decompressed bladder, with the bladder filled to 200 mL. In addition, measurements to the nearest point of the external iliac vein and to the superior anterior insertion point of the apex of the penile dorsal suspensory ligament were performed (Figure 1). The angulation medially (for the bladder) and laterally (for the vein) was determined using the ipsilateral inguinal ring. The pubic tubercle was the baseline for this measurement, and the superior ridge of the pubic bone for the zero degree axis tilt was taken using a handheld protractor. If unable to catheterize the cadaver, intra-pelvic measurements were not taken. In addition, the pelvis was tilted in a Trendelenburg position for the measurements (the authors advise positioning the patient in Trendelenburg position for placement of the reservoir in the retropubic space). The insertion point of the superior anterior insertion point of the penile dorsal suspensory ligament at the point of the ring nearest to the pubic bone (using both inguinal rings) was then determined, both in terms of measurement and angulation.

Statistical Analysis Distance measurements were summarized by their means, standard deviations, medians, and ranges. The intra-class correlation coefficient and corresponding asymptotic 95% confidence interval were used to evaluate intrarater reliability [13]. The nonparametric two-sample Wilcoxon ranksum (Mann–Whitney U) test was used to compare distances measured on cadavers from two different sources [14].

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A Guide for IPP Reservoir Placement Main Outcome Measures

Anatomical measurements from the inguinal ring to the bladder, external iliac vein, and superior origin of the dorsal suspensory ligament at the anterior apex of the pendulous penis were analyzed. This study specifically reviews and evaluates the penoscrotal IPP surgical techniques for placement of the reservoir into the retropubic space in the published literature. Results

Figure 1 Cadaver photo showing the ruler with the decompressed bladder, external iliac vein, and the ipsilateral inguinal ring.

Table 1

Of the 28 cadavers, 3 were excluded because of signs of major pelvic surgery, and an additional 6 sides were excluded because of unilateral fibrosis/surgery or difficulty in exposure. Distance measurements are summarized on Table 1. Distance to the decompressed bladder was 5–8 cm (average 6.4 cm) at a 15–35 (average 23) degrees medial measurement from the inguinal ring (Figure 1). Meanwhile, the measurement to the bladder filled with 200 mL of fluid was 1.5–4 cm (average 2.4 cm) from the inguinal ring. The distance from the external iliac vein to the inguinal ring was 2.5–4.5 cm (average 3.4 cm) at a lateral measurement 20–57.5 (average 35.3) degrees from the inguinal ring. The distance from the anterior apex of the penile dorsal suspensory ligament to the inguinal ring was 6–7 cm (average

Summary of anatomical measurements from the inguinal ring to various locations

Both sides (combined) Distance to bladder (degree) Distance to bladder (cm) Distance to vein (degree) Distance to vein (cm) Distance to full bladder (cm) Distance to dorsal susp. ligament Distance to dorsal susp. ligament Right Distance to bladder (degree) Distance to bladder (cm) Distance to vein (degree) Distance to vein (cm) Distance to full bladder (cm) Distance to dorsal susp. ligament Distance to dorsal susp. ligament Left Distance to bladder (degree) Distance to bladder (cm) Distance to vein (degree) Distance to vein (cm) Distance to full bladder (cm) Distance to dorsal susp. ligament Distance to dorsal susp. ligament

Number of cadavers

Mean (SD)

Median

Range

(cm) (degree)

20 20 20 20 20 6 6

23.0 6.4 35.3 3.4 2.4 6.6 38.6

(5.2) (0.8) (10.2) (0.6) (0.7) (0.4) (9.2)

22 6.2 32 3.4 2.2 6.5 40

(15.0–35.0) (5.0–8.0) (20.0–57.5) (2.5–4.5) (1.5–4.0) (6.0–7.0) (25.0–55.0)

(cm) (degree)

17 17 17 17 17 5 5

24.2 6.5 35.3 3.4 2.3 6.7 42.0

(5.7) (0.8) (10.5) (0.6) (0.7) (0.4) (9.7)

25 6.35 30 3.4 2.2 7 45

(15.0–35.0) (5.4–8.0) (20.0–57.5) (2.5–4.5) (1.5–4.0) (6.0–7.0) (30.0–55.0)

(cm) (degree)

18 18 18 18 18 6 6

21.8 6.3 35.3 3.4 2.5 6.4 35.8

(4.5) (0.7) (10.2) (0.6) (0.7) (0.4) (8.6)

20.5 6.13 33.75 3.35 2.2 6.35 35

(15.0–30.0) (5.0–7.9) (20.0–57.5) (2.5–4.1) (1.8–4.0) (6.0–7.0) (25.0–45.0)

SD = standard deviation

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276 Table 2

Both sides Distance Distance Distance Distance Distance Right Distance Distance Distance Distance Distance Left Distance Distance Distance Distance Distance

Henry et al. ent between the two sites, which suggest either variability in the way these were measured or true differences between the cadavers examined [15]. A PubMed review revealed multiple publications discussing complications of surgical placement of the reservoir. However, none of these articles report on the pertinent anatomical measurements, and these articles lack careful, step-bystep description of placement into the retropublic space.

Summary of intrarater reliability

Number of cadavers

Intra-class correlation coefficient (95% CI)

to to to to to

bladder (degree) bladder (cm) vein (degree) vein (cm) full bladder (cm)

9 9 9 9 9

0.74 0.93 0.90 0.92 0.94

(0.51–0.97) (0.87–1.00) (0.81–1.00) (0.85–1.00) (0.88–1.00)

to to to to to

bladder (degree) bladder (cm) vein (degree) vein (cm) full bladder (cm)

6 6 6 6 6

0.71 0.91 0.92 0.94 0.98

(0.30–1.13) (0.78–1.05) (0.80–1.05) (0.83–1.04) (0.94–1.02)

to to to to to

bladder (degree) bladder (cm) vein (degree) vein (cm) full bladder (cm)

9 9 9 9 9

0.80 0.96 0.90 0.92 0.92

(0.57–1.04) (0.90–1.01) (0.76–1.03) (0.82–1.02) (0.82–1.02)

Discussion

The most significant concern that prosthetic implanters have with three-piece IPP is blind placement of the reservoir in the space of Retzius (SOR)/retropubic space. Reservoir placement in the SOR has been associated with the most devastating complications with this procedure including bladder, bowel, and vascular injuries [16]. The increasing popularity of roboticassisted laparoscopic prostatectomy (RALP) has added additional challenges to placing a reservoir in the SOR because the space becomes obliterated with this technique [17]. A recent study has shown that 82% of experienced implant surgeons feel that placing a reservoir in the SOR in RALP patients is more difficult [18]. These recent concerns of reservoir placement in the SOR, particularly in RALP patients, have fueled the recent interest in alternative reservoir placement sites.

CI = confidence interval

6.6 cm) and 25–55 (average 38.6) degrees superior to the inguinal ring. Intrarater reliability was performed using nine cadavers (Table 2). The intra-class correlation was high for all measurements (P < 0.001), indicating high consistency in the measurement across surgeons. A comparison of measurements between the two study sites are summarized in Table 3. Only distance to vein in centimeters and distance to the full bladder in centimeters were significantly differTable 3

Comparison of measurements between the two study sites Primary site

Both sides Distance Distance Distance Distance Distance Right Distance Distance Distance Distance Distance Left Distance Distance Distance Distance Distance

Secondary site

Number of cadavers

Mean (SD)

Number of cadavers

Mean (SD)

P value*

to to to to to

bladder (degree) bladder (cm) vein (degree) vein (cm) full bladder (cm)

14 14 14 14 14

23.2 6.5 34.8 3.2 2.6

(5.4) (0.8) (11.2) (0.5) (0.7)

6 6 6 6 6

22.5 6.1 36.3 3.7 2.0

(5.0) (0.7) (8.3) (0.4) (0.3)

0.8472 0.1980 0.4386 0.0068 0.0023

to to to to to

bladder (degree) bladder (cm) vein (degree) vein (cm) full bladder (cm)

11 11 11 11 11

24.8 6.6 34.3 3.2 2.6

(6.2) (0.9) (11.5) (0.5) (0.7)

6 6 6 6 6

23.2 6.2 37.2 3.7 1.9

(5.1) (0.6) (9.2) (0.5) (0.3)

0.5771 0.4504 0.6026 0.1302 0.0171

to to to to to

bladder (degree) bladder (cm) vein (degree) vein (cm) full bladder (cm)

12 12 12 12 12

21.8 6.4 35.3 3.2 2.7

(4.3) (0.7) (11.4) (0.6) (0.8)

6 6 6 6 6

21.8 6.0 35.3 3.8 2.0

(5.3) (0.8) (8.2) (0.4) (0.3)

0.9622 0.4530 0.8140 0.0208 0.0561

*Wilcoxon rank-sum (Mann–Whitney U) test SD = standard deviation

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A Guide for IPP Reservoir Placement Despite the significant consequences of reservoir placement, there have not been any studies to date specifically addressing the relationship of the reservoir with important adjacent anatomic landmarks. The published literature on surgical placement of the reservoir into the retropubic space does not appear to have a careful, clearly descriptive, step-by-step guide for inexperienced prosthetic urologists [10–12,19–22]. In fact, with a PubMed search using the terms “penile prosthesis reservoir placement,” only 36 entries appear (accessed July 29, 2013). Of these, only one publication provides an illustration of the surgical techniques of reservoir placement [23]. Additionally, a number of publications have focused on techniques of “ectopic” reservoir placement, but do not provide a step-by-step guide to the “traditional” SOR reservoir placement [24,25]. Most physicians complete their anatomic training in medical school and receive minimal additional anatomic training afterward. Some physicians interested in urologic prosthetics can receive additional cadaver training in the form of industry-sponsored labs; however, this does not include careful dissection of the pelvis and evaluation of these important landmarks and their relative distances. The present study is the first study (to the authors’ knowledge) to carefully evaluate these important anatomic landmarks of surgical placement of the reservoir into the SOR. Additionally, this study emphasizes the relatively short distance of the IPP reservoir in the SOR to the filled bladder and the external iliac vein. Importantly, the second site did not place the cadaver in the Trendelenburg position, which resulted in even closer measurements than the primary study site. These findings reveal that placing the patient in the Trendelenburg position should help achieve greater distance of both the bladder and the external iliac vein from the inguinal ring for reservoir placement in the SOR. The previously mentioned concerns are not moot and should not be underestimated. The development and current use of two-piece prostheses emphasize these points. Despite the less favorable flaccidity and rigidity profiles and lower patient satisfaction rates compared with the threepiece IPP, some surgeons still prefer to use the two-piece IPP because of these very concerns [26]. Are surgeon practice patterns changing to place two-piece IPP in patients because of these concerns over reservoir placement? Are surgeons using more two-piece IPPs because of a paucity of published literature addressing guiding placement?

Multiple experienced and published prosthetic surgeons performed this study at various locations to eliminate observer bias and to test the reproducibility of these results. Consideration was given to using magnetic resonance imaging (MRI) images of the SOR to evaluate the relationships of the SOR. MRI imaging is costly and would be cost prohibitive in a prospective study that is adequately powered. Moreover, retrospective evaluations of MRI images are flawed because of inconsistent bladder volumes among subjects. Using a cadaver model, we were able to evaluate the distance to the bladder precisely with a completely decompressed bladder using a standardized volume of 200 mL. Additionally, the cadaver model allowed for evaluation of relative distances from the external inguinal ring from a real-life surgical perspective than a radiographic perspective.

Conclusions

A study of the anatomical measurements of the retropubic space reveals the importance of bladder decompression and avoiding placement too lateral to the inguinal ring, as the external iliac vein is closer than anticipated by many surgeons. Trendelenburg is critical in reducing the risk of bladder injury, and likely vascular injury as well. In Table 3, the Trendelenburg and nonTrendelenburg sites are compared, with the angle of Trendelenburg being approximated at 20 degrees. The critical comparison is distance to full bladder of 2.6 cm for the Trendelenburg site vs. 2.0 cm for the non-Trendelenburg site. This is statistically significant. Trendelenburg increases the distance of reservoir to full bladder. In theory, Trendelenburg should decompress the external iliac vein, thus making reservoir placement safer from a vascular standpoint as well. But likely, this anatomy was distorted in the cadaver and could not be definitively demonstrated. A surgeon should have an arsenal of tools and options when considering reservoir placement, so even difficult situations can be navigated. While a “perseverance at all costs” approach seems a bit extreme, there should be an option for even the most challenging anatomy. Options available to the surgeon include the ectopic vs. retropubic space, assessing both the left and the right sides, slight underfilling of the reservoir if possible, use of additional tools such as a nasal speculum, and even making a counter-incision. In extreme cases such as patients with transplanted organs in the J Sex Med 2014;11:273–278

278 pelvis or those who have had cystectomies, preemptively choosing semirigid devices or an Ambicor or self-contained inflatable device could be considered, although the above troubleshooting options can still be employed successfully. Placing a reservoir through the inguinal canal can always be done or at least attempted, although an understanding of options to circumvent this approach should be known, and methods of mitigating danger such as Trendelenburg and proper technique should be practiced. Corresponding Author: Gerard Henry, MD, Regional Urology, 255 Bert Kouns—Industrial Loop, Shreveport, LA 71106, USA. Tel: (318) 683-0411; Fax: (318) 683-0743; E-mail: [email protected] Conflict of Interest: The authors report no conflicts of interest. References 1 Rajpurkar A, Bianco FF Jr, Al-Omar O, Terlecki R, Dhabuwala C. Fate of the retained reservoir after replacement of 3-piece penile prosthesis. J Urol 2004;172:664–6. 2 Wilson SK, Henry GD, Delk JR Jr, Cleves MA. The mentor Alpha 1 penile prosthesis with reservoir lock-out valve: Effective prevention of auto-inflation with improved capability for ectopic reservoir placement. J Urol 2002;168(4 Pt 1):1475–8. 3 Munoz JJ, Ellsworth PI. The retained penile prosthesis reservoir: A risk. Urology 2000;55:949–52. 4 Garber BB, Morris A. Intravesical penile implant reservoir: Case report, literature review, and strategies for prevention. Int J Impot Res 2013;25:41–4. 5 Kelly MP, Franciose RJ, Lloyd GL. Successful salvage reimplantation of penile prosthesis after reservoir erosion into continent urinary reservoir. Urology 2012;80:e63–4. 6 Sadeghi-Nejad H, Munarriz R, Shah N. Intra-abdominal reservoir placement during penile prosthesis surgery in post-robotically assisted laparoscopic radical prostatectomy patients: A case report and practical considerations. J Sex Med 2011;8:1547–50. 7 Kramer AC, Chason J, Kusakabe A. Report of two cases of bladder perforation caused by reservoir of inflatable penile prosthesis. J Sex Med 2009;6:2064–7. 8 Deho F, Henry GD, Marone EM, Sacca A, Chiesa R, Rigatti P, Montorsi F. Severe vascular complication after implantation of a three-piece inflatable penile prosthesis. J Sex Med 2008;5:2956–9. 9 Eldefrawy A, Kava BR. An unusual complication during inflatable penile prosthesis implantation. Urology 2010;76:847.

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Henry et al. 10 Henry GD, Laborde E. A review of surgical techniques for impending distal erosion and intraoperative penile implant complications: Part 2 of a three-part review series on penile prosthetic surgery. J Sex Med 2012;9:927–36. 11 Wilson SK, Henry GD. Penoscrotal approach for three-piece and two-piece hydraulic penile implants. In: Mulchay JJ, ed. Atlas of the urologic clinics of North America: Surgical management of erectile dysfunction. Philadelphia: W.B. Saunders; 2002:169–80. 12 Karpman E. Streamlined approach for infrapubic placement of an inflatable penile prosthesis. Adv Urol 2012;2012: 520180-6. 13 Shrout PE, Fleiss JL. Intraclass correlations: Uses in assessing rater reliability. Psychol Bull 1979;86:420–8. 14 Conover WJ. Practical Nonparametric Statistics. 3rd edition. New York: John Wiley & Sons; 1999:272–6. 15 Cleves MA, Gould WW, Gutierrez RG. An introduction to survival analysis using STATA. College Station, TX: Stata Press; 2002:51–69, 93–102, 113–115. 16 Levine LA, Hoeh MP. Review of penile prosthetic reservoir: Complications and presentation of a modified reservoir placement technique. J Sex Med 2012;9:2759–69. 17 Lowrance WT, Eastham JA, Savage C, Maschino AC, Laudone VP, Dechet CB, Stephenson RA, Scardino PT, Sandhu JS. Contemporary open and robotic radical prostatectomy practice patterns among urologists in the United States. J Urol 2012;187:2087–92. 18 Karpman E, Sadeghi-Nejad H, Henry G, Khera M, Morey AF. Current opinions on alternative reservoir placement for inflatable penile prosthesis among members of the Sexual Medicine Society of North America. J Sex Med 2013;10:2115–20. 19 Wilson SK, Henry GD, Delk JR II, Cleves MA. The mentor Alpha 1 penile prosthesis with reservoir lock-out valve: Effective prevention of auto-inflation with improved capability for ectopic reservoir placement. J Urol 2002;168(4 Pt 1):1475–8. 20 Henry GD. Historical review of penile prosthesis design and surgical techniques: Part 1 of a three-part review series on penile prosthetic surgery. J Sex Med 2009;6:675–81. 21 Henry GD, Kramer AC, Carrion RE, Christine B. Advances in prosthetic urology. Adv Urol 2012;2012:681918. doi: 10.1155/ 2012/681918. 22 Henry GD, Wilson SK. Updates in inflatable penile prostheses. Urol Clin North Am 2007;34:535–47. 23 Perito P, Wilson SK. Traditional (retroperitoneal) and abdominal wall (ectopic) reservoir placement. J Sex Med 2011;8:656–9. 24 Morey AF, Cefalu CA, Hudak SJ. High submuscular placement of urologic prosthetic balloons and reservoirs via transscrotal approach. J Sex Med 2013;10:603–10. 25 Levine LA, Hoeh MP. Review of penile prosthetic reservoir: Complications and presentation of a modified reservoir placement technique. J Sex Med 2012;9:2759–69. 26 Lux M, Reyes-Vallejo L, Morgentaler A, Levine LA. Outcomes and satisfaction rates for the redesigned 2-piece penile prosthesis. J Urol 2007;177:262–6.

A guide for inflatable penile prosthesis reservoir placement: pertinent anatomical measurements of the retropubic space.

The primary concern for many prosthetic urologic surgeons in placing the three-piece inflatable penile prosthesis (IPP) is the concept of "blind reser...
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