International Journal of Impotence Research (2014) 27, 86–89 © 2014 Macmillan Publishers Limited All rights reserved 0955-9930/14 www.nature.com/ijir
ORIGINAL ARTICLE
Comparison of infrapubic versus transcrotal approaches for inflatable penile prosthesis placement: a multi-institution report LW Trost1, AG Boonjindasup2 and WJG Hellstrom2 Inflatable penile prostheses (IPP) are associated with excellent long-term outcomes. To date, no study has evaluated the significance of surgical approach on IPP intraoperative variables. High-volume surgeons placing the Titan 0-degree prosthesis from March-July 2012 completed questionnaires including pre-/intraoperative variables. Intraoperative data were compared between surgeons performing an infrapubic versus transcrotal approach for total length of prosthesis, proximal and distal measurements, rear-tip extender (RTE) length, reservoir size and fill volume and ability to place the reservoir in the space of Retzius. Forty-six surgeons placed 256 IPPs, with a median of 5 (range 1–10) inserted. Transcrotal placement was performed most commonly (80%). Revision procedures accounted for 13% of cases, with 19% previously undergoing robotic-assisted prostatectomy. Compared with infrapubic, transcrotal placement resulted in a longer total prosthesis (22.3 cm vs 20.6 cm, Po 0.0001), increased proximal dilation (10.1 cm vs 8.6 cm, P o0.0001), longer RTEs (1.9 cm vs 1.2 cm, P o0.0001) and larger reservoir fill volume (79 cc vs 71 cc, P = 0.0003). No differences were noted in distal measurements or ability to place the reservoir in the space of Retzius. Compared with the infrapubic approach, high-volume surgeons placing the Titan 0-degree IPP transcrotally achieved increased proximal dilation with an ~ 1–2-cm-longer prosthesis inserted. International Journal of Impotence Research (2014) 27, 86–89; doi:10.1038/ijir.2014.35; published online 23 October 2014
INTRODUCTION Placement of an inflatable penile prosthesis (IPP) for the management of erectile dysfunction is commonly employed following inadequate response to more conservative measures. Since its popularization in 1973, ongoing device enhancements have resulted in excellent functional outcomes with minimal complication rates and high overall satisfaction.1,2 Contemporary techniques for IPP placement include the infrapubic and transcrotal approaches.3,4 Advantages of the infrapubic approach include more rapid device placement and direct visualization during reservoir insertion, although a recent study has challenged the latter claim.5 Disadvantages may include difficulty with pump placement, limited corporeal exposure and increased risk of damage to sensory nerves of the penis, particularly with revision cases.5,6 The transcrotal approach is currently the most commonly utilized technique, with ~ 80% of IPPs placed in this fashion.7 Purported advantages include improved ability to secure the pump in the dependent portions of the scrotum, improved corporal exposure and visualization of urethra and minimal risk for nerve damage with placement. Comparisons between techniques are very limited, with available data demonstrating equivalent infection rates and patient satisfaction scores.8,9 No published data are available comparing intra- or postoperative functional outcomes between techniques. The goal of the current study is to review intraoperative outcomes between surgeons placing IPPs via the infrapubic versus transcrotal approach. Results included data on the size of devices
inserted, lengths of measurements achieved, volume of reservoir/ fluid inserted and ability to successfully insert the reservoir, among others. Patient-specific outcomes including demographics, detailed disease-specific history, satisfaction and follow-up results were not captured owing to inherent logistical difficulties with involving a large number of participating providers and institutions required. SUBJECTS AND METHODS Between March 2012 and July 2012, selected surgeons placing Coloplast (Minneapolis, MN, USA) Titan 0-degree prostheses were requested to prospectively complete a multi-item questionnaire postoperatively to assess the ease of placement and overall experience with the new device. All surgeons were selected by Coloplast to participate in the study and were included, in part, owing to high-volume IPP practices, with all cases performed, on average, over a o 2-month survey period. Surgeons were requested to complete surveys on consecutive cases, with no more than 10 cases permitted per surgeon, so as to limit the impact of any one surgeon on the overall results. All surgeons were requested to perform placement of a Titan 0-degree three-piece penile prosthesis if felt to be clinically appropriate. All surgeons were encouraged to place the devices per their standard surgical approach (infrapubic versus transcrotal). No specific training, instruction, guidelines or standardization of measurement techniques were provided to surgeons placing the device. The non-validated questionnaire created by Coloplast included patient clinical factors (previous robotic prostatectomy (yes/no)), intraoperative variables (revision (yes/no), side-specific proximal measurements, size of the device implanted, presence of and size rear-tip extenders (RTEs), reservoir size, surgical approach (infrapubic vs scrotal), reservoir fill volume
1 Department of Urology, Mayo Clinic, Rochester, MN, USA and 2Tulane University Health Sciences Center, Department of Urology, Tulane University School of Medicine, New Orleans, LA, USA. Correspondence: Dr WJG Hellstrom, Tulane University Health Sciences Center, Department of Urology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-42, New Orleans, LA 70112, USA. E-mail: [email protected] Received 17 December 2013; revised 12 August 2014; accepted 11 September 2014; published online 23 October 2014
Infrapubic versus transcrotal penile prosthesis LW Trost et al
87 and residual volume in cylinders), surgeon name and preferred dilating instrument, as well as questions regarding surgeon experience with device placement and overall feedback. Surgeons were requested to complete the questionnaire immediately postoperatively to assure accurate reporting. All data were subsequently compiled by Coloplast and made available to requesting surgeons who participated in the assessment. Data obtained were analyzed and categorized based on the surgical approach utilized for IPP placement (infrapubic vs transcrotal). Patients missing data on surgical approach were excluded from comparative analysis; however, cases with missing data were counted toward the surgeon’s limit of 10 cases. Intraoperative variables were subsequently compared between groups to assess for statistical differences. In cases of discrepancy between bilateral sizing (for example, proximal measurements, RTEs) an average of the two measurements was utilized. Six clerical errors were identified (proximal measurements were identical to total prosthesis length), and the proximal measurements were excluded (five from transcrotal approaches, one from infrapubic). Institutional review was not required, as the data set was obtained through Coloplast with no patient identifiers recorded in the data set. Statistical analysis was performed using JMP 10 statistical software (SAS, Cary, NC, USA), with a two-sided, unpaired student’s t-test, Fisher’s exact test and Pearson’s χ2-test utilized where appropriate. A Bonferroni correction was performed for proximal measurements, distal measurements and total length as these factors all related to total length of prosthesis, with a P-value of 0.02 selected as significant. For all other tests, a P-value of 0.05 was considered statistically significant.
RESULTS A total of 46 high-volume surgeons performing a combined 256 cases completed questionnaires following implantation of the Coloplast 0-degree, three-piece penile prosthesis. The median number of cases performed during the study period was five (range 1–10; surgeons capped at 10 cases). The interval between the first and last case reported was, on average, 53 days. On the basis of the number of surveys returned during the study period, the mean/median number of IPPs performed was estimated at 62/39 cases per surgeon per year, respectively. However, this likely represents an underestimation of the true total surgeon volume, as surgeons would have likely placed other devices during the study period, which would therefore have not been captured in the current survey. Twenty-one cases did not contain information on surgical approach utilized. Two surgeons utilized both infrapubic and transcrotal approaches with 66% (10/15 cases) performed transcrotally. Among the remaining 44 surgeons, nine (20%; 9/44) placed a combined 54 prostheses (25% of total number of prostheses; 54/220) infrapubically, with 35 (80%; 35/44) surgeons placing 166 (75%; 166/220) prostheses transcrotally. Patient demographic information, complications, outcomes and follow-up were not captured in the database. Clinical variables obtained included the indication as a primary versus revision surgery and prior prostatectomy status. A total of 31 cases (13%, 31/247—includes cases without approach identified) were performed as a (non-infected) revision procedure, with equal percentages performed transcrotally (13%, 22/163) and infrapubically (13%, 8/64). One-hundred and sixty-six patients had previously undergone prostatectomy, with 19% (31/166) performed robotically. A non-statistically significant difference was noted between groups with the number of patients undergoing robotic prostatectomy (transcrotal—21%, 24/116; infrapubic 9%, 3/35; P = 0.13). Compared with the infrapubic approach, transcrotal placement of IPPs resulted in a significantly longer implant, proximal measurements, RTEs and total reservoir fill volume (scrotal vs infrapubic: implant size: 22.3 cm vs 20.6 cm, P o 0.0001; proximal meaurements: 10.1 cm vs 8.6 cm, P o0.0001; RTE: 1.9 cm vs 1.2 cm, P o0.0001; reservoir volume: 79 cc vs 71 cc, P = 0.0003). See Figure 1 for boxplot summary of total length of prosthesis by the surgeon and the surgical approach. No significant differences were identified between groups in regard to ability to place the pump in the space of Retzius (scrotal–92% vs infrapubic 89% © 2014 Macmillan Publishers Limited
Figure 1. Boxplot graphical representation of inflatable penile prosthesis length by the surgeon and the surgical approach.
successful, P = 0.59), distal measurements (scrotal: 12.1 cm vs infrapubic: 11.8 cm, P = 0.44), or proximal length percentage of total implant size (scrotal: 45.8% vs infrapubic: 43.6%, P = 0.06). All surgeons reported being able to properly seat the device proximally. Discrepant RTEs were placed in 12% (20/171) of transcrotal vs 6% (4/64) of infrapubic cases, P = 0.33. Among the 24 patients with discrepant RTEs, nine had non-matching proximal measurements. Data were not recorded on the differential breakdown of distal measurements. In comparing transcrotal versus infrapubic approaches between the two surgeons who performed both procedures (n = 15 cases combined), there were no statistically significant differences noted (scrotal vs infrapubic: proximal measurements (10.2 cm vs 11.7 cm, P = 0.40), RTE length (2 cm vs 1.5 cm, P = 0.59) and total length (20 cm vs 21.5 cm, P = 0.33)). Table 1 demonstrates a summary of findings. DISCUSSION Placement of IPPs for management of refractory erectile dysfunction has consistently demonstrated excellent outcomes with overall patient satisfaction rates of 92–100%.10–12 Despite these results, up to 30% of patients complain of penile shortening (average 0.75 cm) following the procedure, with decreased length being the most common complaint among dissatisfied patients.9,10,13 Although several adjunctive techniques have been suggested to improve objective penile length following placement of an IPP, there are currently no studies, which directly compare the impact of the surgical approach on postoperative penile lengths or size of prostheses inserted.10,14–18 With limited data available, there does not appear to be a difference in regard to infection rate or overall patient satisfaction when comparing surgical approaches.8,9 Results from the current study indicate that surgeons placing IPPs via a transcrotal approach achieved an ~ 1–2 cm increased length of prosthesis inserted compared with those utilizing an infrapubic approach. Additional findings include increased length of proximal dilation, length of RTEs and total fill volume of the reservoir. Although the increased volume instilled in the reservoirs is of questionable clinical value, this provides indirect evidence International Journal of Impotence Research (2015), 86 – 89
Infrapubic versus transcrotal penile prosthesis LW Trost et al
88 Table 1.
Comparative outcomes of Infrapubic vs transcrotal placement of Titan 0-degree IPP
Number of surgeons Number of cases Revision case (n = yes) If prior prostatectomy, performed robotically? (n = yes)c Total length of prosthesis (cm) Averaged proximal measurement (cm) Distal measurement (cm) Size of implant without RTEs (cm) Averaged RTEs (cm) Reservoir size Total reservoir fill volume
Infrapubic mean (% or s.d.)
Transcrotal mean (% or s.d.)
Total (% or s.d.)a
P-value
11/46 (24)b 59/235 (25)c 8/64 (13) 3/35 (9) 20.6 (2.8) 8.6 (1.7) 11.8 (2.7) 18.3 (1.65) 1.2 (1.0) 81 cc (17 cc) 71 cc (13 cc)
37/46 (80)b 176/235 (75)c 22/163 (13) 24/116 (21) 22.3 (2.6) 10.1 (1.6) 12.1 (2.2) 18.6 (1.6) 1.8 (1.2) 85 cc (20 cc) 79 cc (16 cc)
46 256 31/247 (13) 31/166 (19) 21.9 (2.8) 9.9 (2.8) 11.9 (3.3) 18.6 (1.6) 1.7 (1.2) 84 cc (19 cc) 77 cc (15 cc)
1.00 0.13 o 0.0001d o 0.0001d 0.44d 0.25 o0.0001 0.18 0.0003
Abbreviations: IPP, inflatable penile prosthesis; RTEs, rear-tip extenders. All others significant at P = 0.05. aAll cases with data available, including if approach not listed. bIncludes two surgeons performing both techniques. cIncludes only cases with data available on approach performed. dStatistical significance set at P = 0.02.
that larger prostheses were inserted in the transcrotal group. Both approaches were not statistically different in regard to baseline patient characteristics (revision surgery and prior robotic-assisted prostatectomy), distal measurements or ability to place the reservoir in the space of Retzius. Although the ability to place the reservoir under direct vision is commonly identified as an advantage to infrapubic placement, no differences were reported in the ability to place the reservoir in the space of Retzius, with equivalent rates of prior robotic-assisted prostatectomy identified between groups. These findings are consistent with other comparative reports, which demonstrate equivalent comfort with reservoir placement regardless of surgical approach.5 The underlying mechanism for increased size of prosthesis inserted with the transcrotal approach is unclear and may be related to several factors. In reviewing proximal and distal measurements, a significantly longer length of proximal measurements is noted in the transcrotal group, with otherwise similar lengths of distal measurement noted. Although the infrapubic and transcrotal approaches likely result in different locations for corporotomy, given that the distal measurements are equivalent, this likely would not account for the observed findings alone. An additional factor, which may contribute toward the increased length, is anatomic factors relating to the infrapubic approach. As the infrapubic approach is more likely to result in corporotomies on the lateral rather than ventral aspect of the corpora, this may result in an altered trajectory of inserted dilators. Dilators inserted from a lateral position may be more likely to result in a medial rather than lateral deflection of the leading tip. This may limit dilation of the proximal-most aspects of the corpora, which have an anatomic deflection laterally as they attach to the pubic rami. Although the transcrotal approach resulted in a longer overall prosthesis inserted in the current series, this is of unclear clinical significance. No measurements were obtained of the penile length following IPP insertion, and distal measurements obtained were not statistically different between groups. This would suggest that although the transcrotal approach may provide additional proximal dilation and longer prosthesis insertion, it is unclear how this may ultimately impact the overall functional penile length. In reviewing the two surgeons who performed both infrapubic and transcrotal placements, no statistically significant differences were identified when stratified by approach. However, ability to detect significant findings is limited by the small number of patients in this select cohort. Although the current study did not obtain information as to any adjunctive procedures performed, it is unlikely that either incision of the suspensory ligament or scrotoplasty would account for the International Journal of Impotence Research (2015), 86 – 89
findings of increased prosthesis length in the transcrotal group. Techniques used for corporal measurement and decisions on oversizing devices are similarly not available, and these discrepancies in measuring could potentially account for the findings noted. However, it would be expected that variations in technique would exist with equal likelihood in both groups. The current study has several notable limitations including the observational nature and lack of a control group. As all surgeons placed a 0-degree Coloplast, three-piece prosthesis, it is unclear whether the current findings would translate to other devices. Also, no standardized method for measurement was employed; rather, all surgeons were encouraged to utilize their standard measurement and surgical techniques. This may introduce confounding variables relating to the underlying technique performed. No attempts were made to account for geographic variability and patient race/ethnicity, which may also introduce patient-related bias. As previously noted, detailed demographic information, clinical history, follow-up information, long-term objective outcomes/measurements and data on patient perceptions are not available, which limits a more thorough comparison and determination of clinical relevance. This also results in an inability to directly compare baseline characteristics including etiology and duration of erectile dysfunction, which prevents confirmation of appropriately matched groupings. Given the large number of participating surgeons and limitation of the number of cases per surgeon, it is not possible to control for the impact of variability in surgical technique on outcomes. This is an inherent limitation in studies of this nature. Despite these limitations, the current study is the first to document comparative outcomes on length of prosthesis inserted and measurements obtained based on the surgical approach performed. The study includes a large number of patients and participating surgeons, which reduces the impact of potentially confounding factors. As all surgeons performed their technique of choice and were selected for participation due to their highvolume practices, outcomes are more likely to represent optimal results achievable with each approach. On the basis of the number of surveys returned, the mean number of Coloplast three-piece IPPs performed per year was estimated at 62. This likely underestimates the actual mean volume of cases performed per surgeon, as it would be expected for the participating surgeons to place devices other than the Coloplast 0-degree IPP during the study period. As these other procedures would not have been captured in the current data set, the total number of prostheses inserted during the study period is likely greater than that which is indicated, highlighting the high-volume nature of the surgeons included. Similarly, given the large number and geographical © 2014 Macmillan Publishers Limited
Infrapubic versus transcrotal penile prosthesis LW Trost et al
representation of surgeons participating, the capping of the number of procedures per surgeon, and the median number of cases per surgeon, it is unlikely that results would be skewed by any one surgeon’s outcomes. This is also supported by the statistical and boxplot analyses reported herein. Although the ideal study would involve a randomized, controlled trial with multiple surgeons, each with experience in both techniques, it is unlikely that such a trial could ever be performed. Insertion of IPPs remains a viable treatment option for men with erectile dysfunction refractory to more conservative measures. Although IPPs result in excellent overall outcomes, a small percentage of patients are dissatisfied, with the most common reason given being decreased penile length. Despite several adjunctive procedures reported to augment penile length at the time of IPP, no prior studies have examined the impact of surgical technique on length of prosthesis inserted. The current study of 46 surgeons performing a combined 235 cases over a short period of time via infrapubic versus transcrotal approaches demonstrates increased length of device inserted, proximal dilation and RTEs with the transcrotal approach. Although these results are intriguing, the numerous limitations inherent to observational surgical data sets suggest a need for further validation and study prior to accepting outcomes at face value. Although randomized, controlled trials are unlikely, same surgeon comparisons using varied techniques and/or cadaveric studies may provide further evidence to support or refute the current observations. In addition, prospective evaluations with pre- and postoperative measured penile lengths and objective measures of overall satisfaction may help to provide clinical context and relevance to the current findings. CONFLICT OF INTEREST The authors delare no conflict of interest.
ACKNOWLEDGMENTS We would wish to acknowledge the participation of the surgeons contributing data to the current project, in alphabetical order—Tony Balchunas, Greg Bales, Joseph Banno, Kevin Barlog, Nelson Bennett, William Bogache, Jeffrey Brady, Todd Brandt, Kevin Brewton, Arnold Bullock, Rafael Carrion, Cully Carson, Brian Christine, Douglas Cummings, Daniel Curhan, Edward Dakil, Chirpriya Dhabuwala, Martin Dineen, Francois Eid, Sheldon Freedman, Bruce Garber, Valal George, Edward Gheiler, Fred Grossman, Wayne Hellstrom, Seth Hollenbach, LeRoy Jones, Tobias Kohler, Andrew Kramer, Barry Lee, Laurence Levine, Alan McCool, Andrew McCullough, Jesse Mills, Allen Morey, Hossein Sadehi Nejad, Dana Ohl, Bashar Omarbasha, Paul Perito, Gary Price, Charles Pritchard, Manish Shaw, Ronald Suh, Ryan Terlecki, Robert Valenzuela and Run Wang.
© 2014 Macmillan Publishers Limited
REFERENCES 1 Scott FB, Bradley WE, Timm GW. Management of erectile impotence. Use of implantable inflatable prosthesis. Urology 1973; 2: 80–82. 2 Trost LW, McCaslin R, Linder B, Hellstrom WJG. Long-term outcomes of penile prostheses for the treatment of erectile dysfunction. Expert Rev Med Devices 2013; 10: 353–366. 3 Baum N, Suarez G, Mobley D. Use of infra-pubic incision for insertion of Mentor Mark II inflatable penile prosthesis. Urology 1992; 39: 436–438. 4 Scarzella GI. Improved technique for implanting AMS 700CX inflatable penile prosthesis using transverse scrotal approach. Urology 1989; 34: 388–389. 5 Kramer A, Chason J. Residents at the University of Maryland Medical System provide insight to learning infrapubic approach for IPP surgery: relative benefits but novel challenges exposed in first 15 cases. J Sex Med 2010; 7: 1298–1305. 6 Montague DK, Angermeir KW. Surgical approaches for penile prosthesis implantation: penoscrotal vs infrapubic. Int J Impot Res 2003; 15: S134–S135. 7 Patient Information Forms (PIF) Data. . American Medical Systems: Minnetonka, MN, USA, 2012. 8 Garber BB, Marcus SM. Does surgical approach affect the incidence of inflatable penile prosthesis infection? Urology 1998; 52: 291–293. 9 Candela JV, Hellstrom WJ. Three-piece inflatable penile prosthesis implantation: a comparison of the penoscrotal and infrapubic surgical approaches. J La State Med Soc 1996; 148: 296–301. 10 Montorsi F, Rigatti P, Carmignani G, Corbu C, Campo B, Ordesi G et al. AMS threepiece inflatable implants for erectile dysfunction: a long-term multi-institutional study in 200 consecutive patients. Eur Urol 2000; 37: 50–55. 11 Natali A, Olianas R, Fisch M. Penile implantation in Europe: successes and complications with 253 implants in Italy and Germany. J Sex Med 2008; 5: 1503–1512. 12 Wilson SK, Delk JR, Salem EA, Cleves MA. Long-term survival of inflatable penile prostheses: single surgical group experience with 2384 first-time implants spanning two decades. J Sex Med 2007; 4: 1074–1079. 13 Wang R, Howard GE, Hoang A, Yuan JH, Lin HC, Dai YT. Prospective and long-term evaluation of erect penile length obtained with inflatable penile prosthesis to that induced by intracavernosal injection. Asian J Androl 2009; 11: 411–415. 14 Kabalin JN, Rosen J, Perkash I. Penile advancement and lengthening in spinal cord injury patients with retracted phallus who have failed penile prosthesis placement alone. J Urol 1990; 144: 316–318. 15 Borges F, Hakim L, Kline C. Surgical technique to maintain penile length after insertion of an inflatable penile prosthesis via infrapubic approach. J Sex Med 2006; 3: 550–553. 16 Martinez-Salamanca JI, Mueller A, Moncada I, Carballido J, Mulhall JP. Penile prosthesis surgery in patients with corporal fibrosis: a state of the art review. J Sex Med 2011; 8: 1880–1889. 17 Henry G, Houghton L, Culkin D, Otheguy J, Shabsigh R, Ohl DA. Comparison of a new length measurement technique for inflatable penile prosthesis implantation to standard techniques: outcomes and patient satisfaction. J Sex Med 2011; 8: 2640–2646. 18 Miranda-Sousa A, Keating M, Moreira S, Baker M, Carrion R. Concomitant ventral phalloplasty during penile implant surgery: a novel procedure that optimizes patient satisfaction and their perception of phallic length after penile implant surgery. J Sex Med 2007; 4: 1494–1499.
International Journal of Impotence Research (2015), 86 – 89
89
ORIGINAL ARTICLE
Comparison of infrapubic versus transcrotal approaches for inflatable penile prosthesis placement: a multi-institution report LW Trost1, AG Boonjindasup2 and WJG Hellstrom2 Inflatable penile prostheses (IPP) are associated with excellent long-term outcomes. To date, no study has evaluated the significance of surgical approach on IPP intraoperative variables. High-volume surgeons placing the Titan 0-degree prosthesis from March-July 2012 completed questionnaires including pre-/intraoperative variables. Intraoperative data were compared between surgeons performing an infrapubic versus transcrotal approach for total length of prosthesis, proximal and distal measurements, rear-tip extender (RTE) length, reservoir size and fill volume and ability to place the reservoir in the space of Retzius. Forty-six surgeons placed 256 IPPs, with a median of 5 (range 1–10) inserted. Transcrotal placement was performed most commonly (80%). Revision procedures accounted for 13% of cases, with 19% previously undergoing robotic-assisted prostatectomy. Compared with infrapubic, transcrotal placement resulted in a longer total prosthesis (22.3 cm vs 20.6 cm, Po 0.0001), increased proximal dilation (10.1 cm vs 8.6 cm, P o0.0001), longer RTEs (1.9 cm vs 1.2 cm, P o0.0001) and larger reservoir fill volume (79 cc vs 71 cc, P = 0.0003). No differences were noted in distal measurements or ability to place the reservoir in the space of Retzius. Compared with the infrapubic approach, high-volume surgeons placing the Titan 0-degree IPP transcrotally achieved increased proximal dilation with an ~ 1–2-cm-longer prosthesis inserted. International Journal of Impotence Research (2014) 27, 86–89; doi:10.1038/ijir.2014.35; published online 23 October 2014
INTRODUCTION Placement of an inflatable penile prosthesis (IPP) for the management of erectile dysfunction is commonly employed following inadequate response to more conservative measures. Since its popularization in 1973, ongoing device enhancements have resulted in excellent functional outcomes with minimal complication rates and high overall satisfaction.1,2 Contemporary techniques for IPP placement include the infrapubic and transcrotal approaches.3,4 Advantages of the infrapubic approach include more rapid device placement and direct visualization during reservoir insertion, although a recent study has challenged the latter claim.5 Disadvantages may include difficulty with pump placement, limited corporeal exposure and increased risk of damage to sensory nerves of the penis, particularly with revision cases.5,6 The transcrotal approach is currently the most commonly utilized technique, with ~ 80% of IPPs placed in this fashion.7 Purported advantages include improved ability to secure the pump in the dependent portions of the scrotum, improved corporal exposure and visualization of urethra and minimal risk for nerve damage with placement. Comparisons between techniques are very limited, with available data demonstrating equivalent infection rates and patient satisfaction scores.8,9 No published data are available comparing intra- or postoperative functional outcomes between techniques. The goal of the current study is to review intraoperative outcomes between surgeons placing IPPs via the infrapubic versus transcrotal approach. Results included data on the size of devices
inserted, lengths of measurements achieved, volume of reservoir/ fluid inserted and ability to successfully insert the reservoir, among others. Patient-specific outcomes including demographics, detailed disease-specific history, satisfaction and follow-up results were not captured owing to inherent logistical difficulties with involving a large number of participating providers and institutions required. SUBJECTS AND METHODS Between March 2012 and July 2012, selected surgeons placing Coloplast (Minneapolis, MN, USA) Titan 0-degree prostheses were requested to prospectively complete a multi-item questionnaire postoperatively to assess the ease of placement and overall experience with the new device. All surgeons were selected by Coloplast to participate in the study and were included, in part, owing to high-volume IPP practices, with all cases performed, on average, over a o 2-month survey period. Surgeons were requested to complete surveys on consecutive cases, with no more than 10 cases permitted per surgeon, so as to limit the impact of any one surgeon on the overall results. All surgeons were requested to perform placement of a Titan 0-degree three-piece penile prosthesis if felt to be clinically appropriate. All surgeons were encouraged to place the devices per their standard surgical approach (infrapubic versus transcrotal). No specific training, instruction, guidelines or standardization of measurement techniques were provided to surgeons placing the device. The non-validated questionnaire created by Coloplast included patient clinical factors (previous robotic prostatectomy (yes/no)), intraoperative variables (revision (yes/no), side-specific proximal measurements, size of the device implanted, presence of and size rear-tip extenders (RTEs), reservoir size, surgical approach (infrapubic vs scrotal), reservoir fill volume
1 Department of Urology, Mayo Clinic, Rochester, MN, USA and 2Tulane University Health Sciences Center, Department of Urology, Tulane University School of Medicine, New Orleans, LA, USA. Correspondence: Dr WJG Hellstrom, Tulane University Health Sciences Center, Department of Urology, Tulane University School of Medicine, 1430 Tulane Avenue, SL-42, New Orleans, LA 70112, USA. E-mail: [email protected] Received 17 December 2013; revised 12 August 2014; accepted 11 September 2014; published online 23 October 2014
Infrapubic versus transcrotal penile prosthesis LW Trost et al
87 and residual volume in cylinders), surgeon name and preferred dilating instrument, as well as questions regarding surgeon experience with device placement and overall feedback. Surgeons were requested to complete the questionnaire immediately postoperatively to assure accurate reporting. All data were subsequently compiled by Coloplast and made available to requesting surgeons who participated in the assessment. Data obtained were analyzed and categorized based on the surgical approach utilized for IPP placement (infrapubic vs transcrotal). Patients missing data on surgical approach were excluded from comparative analysis; however, cases with missing data were counted toward the surgeon’s limit of 10 cases. Intraoperative variables were subsequently compared between groups to assess for statistical differences. In cases of discrepancy between bilateral sizing (for example, proximal measurements, RTEs) an average of the two measurements was utilized. Six clerical errors were identified (proximal measurements were identical to total prosthesis length), and the proximal measurements were excluded (five from transcrotal approaches, one from infrapubic). Institutional review was not required, as the data set was obtained through Coloplast with no patient identifiers recorded in the data set. Statistical analysis was performed using JMP 10 statistical software (SAS, Cary, NC, USA), with a two-sided, unpaired student’s t-test, Fisher’s exact test and Pearson’s χ2-test utilized where appropriate. A Bonferroni correction was performed for proximal measurements, distal measurements and total length as these factors all related to total length of prosthesis, with a P-value of 0.02 selected as significant. For all other tests, a P-value of 0.05 was considered statistically significant.
RESULTS A total of 46 high-volume surgeons performing a combined 256 cases completed questionnaires following implantation of the Coloplast 0-degree, three-piece penile prosthesis. The median number of cases performed during the study period was five (range 1–10; surgeons capped at 10 cases). The interval between the first and last case reported was, on average, 53 days. On the basis of the number of surveys returned during the study period, the mean/median number of IPPs performed was estimated at 62/39 cases per surgeon per year, respectively. However, this likely represents an underestimation of the true total surgeon volume, as surgeons would have likely placed other devices during the study period, which would therefore have not been captured in the current survey. Twenty-one cases did not contain information on surgical approach utilized. Two surgeons utilized both infrapubic and transcrotal approaches with 66% (10/15 cases) performed transcrotally. Among the remaining 44 surgeons, nine (20%; 9/44) placed a combined 54 prostheses (25% of total number of prostheses; 54/220) infrapubically, with 35 (80%; 35/44) surgeons placing 166 (75%; 166/220) prostheses transcrotally. Patient demographic information, complications, outcomes and follow-up were not captured in the database. Clinical variables obtained included the indication as a primary versus revision surgery and prior prostatectomy status. A total of 31 cases (13%, 31/247—includes cases without approach identified) were performed as a (non-infected) revision procedure, with equal percentages performed transcrotally (13%, 22/163) and infrapubically (13%, 8/64). One-hundred and sixty-six patients had previously undergone prostatectomy, with 19% (31/166) performed robotically. A non-statistically significant difference was noted between groups with the number of patients undergoing robotic prostatectomy (transcrotal—21%, 24/116; infrapubic 9%, 3/35; P = 0.13). Compared with the infrapubic approach, transcrotal placement of IPPs resulted in a significantly longer implant, proximal measurements, RTEs and total reservoir fill volume (scrotal vs infrapubic: implant size: 22.3 cm vs 20.6 cm, P o 0.0001; proximal meaurements: 10.1 cm vs 8.6 cm, P o0.0001; RTE: 1.9 cm vs 1.2 cm, P o0.0001; reservoir volume: 79 cc vs 71 cc, P = 0.0003). See Figure 1 for boxplot summary of total length of prosthesis by the surgeon and the surgical approach. No significant differences were identified between groups in regard to ability to place the pump in the space of Retzius (scrotal–92% vs infrapubic 89% © 2014 Macmillan Publishers Limited
Figure 1. Boxplot graphical representation of inflatable penile prosthesis length by the surgeon and the surgical approach.
successful, P = 0.59), distal measurements (scrotal: 12.1 cm vs infrapubic: 11.8 cm, P = 0.44), or proximal length percentage of total implant size (scrotal: 45.8% vs infrapubic: 43.6%, P = 0.06). All surgeons reported being able to properly seat the device proximally. Discrepant RTEs were placed in 12% (20/171) of transcrotal vs 6% (4/64) of infrapubic cases, P = 0.33. Among the 24 patients with discrepant RTEs, nine had non-matching proximal measurements. Data were not recorded on the differential breakdown of distal measurements. In comparing transcrotal versus infrapubic approaches between the two surgeons who performed both procedures (n = 15 cases combined), there were no statistically significant differences noted (scrotal vs infrapubic: proximal measurements (10.2 cm vs 11.7 cm, P = 0.40), RTE length (2 cm vs 1.5 cm, P = 0.59) and total length (20 cm vs 21.5 cm, P = 0.33)). Table 1 demonstrates a summary of findings. DISCUSSION Placement of IPPs for management of refractory erectile dysfunction has consistently demonstrated excellent outcomes with overall patient satisfaction rates of 92–100%.10–12 Despite these results, up to 30% of patients complain of penile shortening (average 0.75 cm) following the procedure, with decreased length being the most common complaint among dissatisfied patients.9,10,13 Although several adjunctive techniques have been suggested to improve objective penile length following placement of an IPP, there are currently no studies, which directly compare the impact of the surgical approach on postoperative penile lengths or size of prostheses inserted.10,14–18 With limited data available, there does not appear to be a difference in regard to infection rate or overall patient satisfaction when comparing surgical approaches.8,9 Results from the current study indicate that surgeons placing IPPs via a transcrotal approach achieved an ~ 1–2 cm increased length of prosthesis inserted compared with those utilizing an infrapubic approach. Additional findings include increased length of proximal dilation, length of RTEs and total fill volume of the reservoir. Although the increased volume instilled in the reservoirs is of questionable clinical value, this provides indirect evidence International Journal of Impotence Research (2015), 86 – 89
Infrapubic versus transcrotal penile prosthesis LW Trost et al
88 Table 1.
Comparative outcomes of Infrapubic vs transcrotal placement of Titan 0-degree IPP
Number of surgeons Number of cases Revision case (n = yes) If prior prostatectomy, performed robotically? (n = yes)c Total length of prosthesis (cm) Averaged proximal measurement (cm) Distal measurement (cm) Size of implant without RTEs (cm) Averaged RTEs (cm) Reservoir size Total reservoir fill volume
Infrapubic mean (% or s.d.)
Transcrotal mean (% or s.d.)
Total (% or s.d.)a
P-value
11/46 (24)b 59/235 (25)c 8/64 (13) 3/35 (9) 20.6 (2.8) 8.6 (1.7) 11.8 (2.7) 18.3 (1.65) 1.2 (1.0) 81 cc (17 cc) 71 cc (13 cc)
37/46 (80)b 176/235 (75)c 22/163 (13) 24/116 (21) 22.3 (2.6) 10.1 (1.6) 12.1 (2.2) 18.6 (1.6) 1.8 (1.2) 85 cc (20 cc) 79 cc (16 cc)
46 256 31/247 (13) 31/166 (19) 21.9 (2.8) 9.9 (2.8) 11.9 (3.3) 18.6 (1.6) 1.7 (1.2) 84 cc (19 cc) 77 cc (15 cc)
1.00 0.13 o 0.0001d o 0.0001d 0.44d 0.25 o0.0001 0.18 0.0003
Abbreviations: IPP, inflatable penile prosthesis; RTEs, rear-tip extenders. All others significant at P = 0.05. aAll cases with data available, including if approach not listed. bIncludes two surgeons performing both techniques. cIncludes only cases with data available on approach performed. dStatistical significance set at P = 0.02.
that larger prostheses were inserted in the transcrotal group. Both approaches were not statistically different in regard to baseline patient characteristics (revision surgery and prior robotic-assisted prostatectomy), distal measurements or ability to place the reservoir in the space of Retzius. Although the ability to place the reservoir under direct vision is commonly identified as an advantage to infrapubic placement, no differences were reported in the ability to place the reservoir in the space of Retzius, with equivalent rates of prior robotic-assisted prostatectomy identified between groups. These findings are consistent with other comparative reports, which demonstrate equivalent comfort with reservoir placement regardless of surgical approach.5 The underlying mechanism for increased size of prosthesis inserted with the transcrotal approach is unclear and may be related to several factors. In reviewing proximal and distal measurements, a significantly longer length of proximal measurements is noted in the transcrotal group, with otherwise similar lengths of distal measurement noted. Although the infrapubic and transcrotal approaches likely result in different locations for corporotomy, given that the distal measurements are equivalent, this likely would not account for the observed findings alone. An additional factor, which may contribute toward the increased length, is anatomic factors relating to the infrapubic approach. As the infrapubic approach is more likely to result in corporotomies on the lateral rather than ventral aspect of the corpora, this may result in an altered trajectory of inserted dilators. Dilators inserted from a lateral position may be more likely to result in a medial rather than lateral deflection of the leading tip. This may limit dilation of the proximal-most aspects of the corpora, which have an anatomic deflection laterally as they attach to the pubic rami. Although the transcrotal approach resulted in a longer overall prosthesis inserted in the current series, this is of unclear clinical significance. No measurements were obtained of the penile length following IPP insertion, and distal measurements obtained were not statistically different between groups. This would suggest that although the transcrotal approach may provide additional proximal dilation and longer prosthesis insertion, it is unclear how this may ultimately impact the overall functional penile length. In reviewing the two surgeons who performed both infrapubic and transcrotal placements, no statistically significant differences were identified when stratified by approach. However, ability to detect significant findings is limited by the small number of patients in this select cohort. Although the current study did not obtain information as to any adjunctive procedures performed, it is unlikely that either incision of the suspensory ligament or scrotoplasty would account for the International Journal of Impotence Research (2015), 86 – 89
findings of increased prosthesis length in the transcrotal group. Techniques used for corporal measurement and decisions on oversizing devices are similarly not available, and these discrepancies in measuring could potentially account for the findings noted. However, it would be expected that variations in technique would exist with equal likelihood in both groups. The current study has several notable limitations including the observational nature and lack of a control group. As all surgeons placed a 0-degree Coloplast, three-piece prosthesis, it is unclear whether the current findings would translate to other devices. Also, no standardized method for measurement was employed; rather, all surgeons were encouraged to utilize their standard measurement and surgical techniques. This may introduce confounding variables relating to the underlying technique performed. No attempts were made to account for geographic variability and patient race/ethnicity, which may also introduce patient-related bias. As previously noted, detailed demographic information, clinical history, follow-up information, long-term objective outcomes/measurements and data on patient perceptions are not available, which limits a more thorough comparison and determination of clinical relevance. This also results in an inability to directly compare baseline characteristics including etiology and duration of erectile dysfunction, which prevents confirmation of appropriately matched groupings. Given the large number of participating surgeons and limitation of the number of cases per surgeon, it is not possible to control for the impact of variability in surgical technique on outcomes. This is an inherent limitation in studies of this nature. Despite these limitations, the current study is the first to document comparative outcomes on length of prosthesis inserted and measurements obtained based on the surgical approach performed. The study includes a large number of patients and participating surgeons, which reduces the impact of potentially confounding factors. As all surgeons performed their technique of choice and were selected for participation due to their highvolume practices, outcomes are more likely to represent optimal results achievable with each approach. On the basis of the number of surveys returned, the mean number of Coloplast three-piece IPPs performed per year was estimated at 62. This likely underestimates the actual mean volume of cases performed per surgeon, as it would be expected for the participating surgeons to place devices other than the Coloplast 0-degree IPP during the study period. As these other procedures would not have been captured in the current data set, the total number of prostheses inserted during the study period is likely greater than that which is indicated, highlighting the high-volume nature of the surgeons included. Similarly, given the large number and geographical © 2014 Macmillan Publishers Limited
Infrapubic versus transcrotal penile prosthesis LW Trost et al
representation of surgeons participating, the capping of the number of procedures per surgeon, and the median number of cases per surgeon, it is unlikely that results would be skewed by any one surgeon’s outcomes. This is also supported by the statistical and boxplot analyses reported herein. Although the ideal study would involve a randomized, controlled trial with multiple surgeons, each with experience in both techniques, it is unlikely that such a trial could ever be performed. Insertion of IPPs remains a viable treatment option for men with erectile dysfunction refractory to more conservative measures. Although IPPs result in excellent overall outcomes, a small percentage of patients are dissatisfied, with the most common reason given being decreased penile length. Despite several adjunctive procedures reported to augment penile length at the time of IPP, no prior studies have examined the impact of surgical technique on length of prosthesis inserted. The current study of 46 surgeons performing a combined 235 cases over a short period of time via infrapubic versus transcrotal approaches demonstrates increased length of device inserted, proximal dilation and RTEs with the transcrotal approach. Although these results are intriguing, the numerous limitations inherent to observational surgical data sets suggest a need for further validation and study prior to accepting outcomes at face value. Although randomized, controlled trials are unlikely, same surgeon comparisons using varied techniques and/or cadaveric studies may provide further evidence to support or refute the current observations. In addition, prospective evaluations with pre- and postoperative measured penile lengths and objective measures of overall satisfaction may help to provide clinical context and relevance to the current findings. CONFLICT OF INTEREST The authors delare no conflict of interest.
ACKNOWLEDGMENTS We would wish to acknowledge the participation of the surgeons contributing data to the current project, in alphabetical order—Tony Balchunas, Greg Bales, Joseph Banno, Kevin Barlog, Nelson Bennett, William Bogache, Jeffrey Brady, Todd Brandt, Kevin Brewton, Arnold Bullock, Rafael Carrion, Cully Carson, Brian Christine, Douglas Cummings, Daniel Curhan, Edward Dakil, Chirpriya Dhabuwala, Martin Dineen, Francois Eid, Sheldon Freedman, Bruce Garber, Valal George, Edward Gheiler, Fred Grossman, Wayne Hellstrom, Seth Hollenbach, LeRoy Jones, Tobias Kohler, Andrew Kramer, Barry Lee, Laurence Levine, Alan McCool, Andrew McCullough, Jesse Mills, Allen Morey, Hossein Sadehi Nejad, Dana Ohl, Bashar Omarbasha, Paul Perito, Gary Price, Charles Pritchard, Manish Shaw, Ronald Suh, Ryan Terlecki, Robert Valenzuela and Run Wang.
© 2014 Macmillan Publishers Limited
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