Inflatable penile prostheses for the treatment of erectile dysfunction: an update

History of penile implants: from implants made of bone to modern inflatable penile implants

Penile prostheses are implantable devices used to definitively treat erectile dysfunction when previous forms of treatment have failed. The first example of a penile implant dates to 1935, when a rib was inserted in a neo-phallus reconstructed after a traumatic amputation. Since then, alternative artificial devices were adopted as penile prosthetic implants. The evolution of prosthetic devices had a dramatic thrust in 1973 when the first inflatable penile prosthesis was worldwide presented. Thanks to advances in device materials, design, surgical implant techniques, and perioperative management, nowadays inflatable penile prostheses are one of the most adopted definitive therapy for patients with drug-refractory erectile dysfunction or refusing alternative forms of treatments. Moreover, the clinical indications for inflatable penile prosthesis have also expanded, including female-to-male transmen or men underwent penile reconstruction due to congenital aphallia or traumatic or surgical penile amputation. In order to summarise the process behind the development and evolution of penile prosthesis, we aimed at performing a historical review of the currently available literature to provide an easy and comprehensive overview of the topic. The understanding of the historical process behind the evolution of inflatable penile prostheses will drive further innovation to increase efficiency and the rate of patients satisfaction.

Evaluation of Bacteria in a Novel In Vitro Biofilm Model of Penile Prosthesis

BACKGROUND

Delayed infection, thought to be due to gradual biofilm formation, remains a feared complication after inflatable penile prosthesis (IPP) insertion. Understanding and preventing biofilm formation is necessary to prevent infections.

AIM

To develop an in vitro model and compare growth of biofilm by different bacteria on IPPs and evaluate the anti-infective efficacy of the Coloplast Titan and AMS 700 InhibiZone.

METHODS

Sterile IPPs (Coloplast) were cut into rings and incubated with S. epidermidis, S. aureus, P. aeruginosa, A. baumannii, or K. pneumoniae cultures in tryptic soy broth (TSB) (4 hour) to ensure adequate bacteria attachment, and then in only TSB (120 hours) to allow for biofilm formation. Rings were fixed with ethanol and biofilm measured by spectrophotometer (OD570) after crystal violet staining. This methodology was repeated for S. epidermidis and P. aeruginosa with Coloplast rings dipped in 10 ml of a 10 mg/ml Rifampin, 1 mg/ml Gentamicin, and deionized water solution and undipped AMS InhibiZone rings. Crystal violet assay (OD570) was repeated after incubation within bacteria (2 hour), and then only TSB (120 hours).

OUTCOMES

The primary outcome of the study was OD570 readings, indirectly measuring biofilm mass on implant rings.

RESULTS

S. epidermidis, S. aureus, A. baumannii, P. aeruginosa, and K. pneumoniae all formed significant biofilm. P. aeruginosa showed the strongest predilection to grow biofilm on IPPs. P. aeruginosa also formed significant biofilm on antibiotic-treated Coloplast and AMS rings, while S. epidermidis was inhibited. No significant difference was found in biofilm inhibition between the implants.

CLINICAL TRANSLATION

Our findings suggest gram-negative bacteria may form biofilm more proficiently and quickly on IPPs than gram-positive organisms. Commonly used antibiotic treatments on IPPs may be effective against S. epidermidis but not against P. aeruginosa biofilm formation.

STRENGTHS & LIMITATIONS

This is the first study comparing biofilm formation by different bacteria organisms on IPPs and the inhibitive ability of Coloplast and AMS implants against biofilm formation. Clinical data on organisms responsible for infected IPPs is needed to determine the clinical relevance of our findings.

CONCLUSION

Our novel in vitro model of biofilm formation of IPPs evaluated the effect of a gentamicin/rifampin antibiotic dip on Coloplast Titan implants and the anti-infective capacity of the minocycline/rifampin precoated AMS 700 InhibiZone against S. epidermidis and P. aeruginosa. P. aeruginosa was able to grow on both antibiotic-treated implants, with no significant difference, and should continue to be a specific target of investigation to reduce delayed post-operative IPP infections. Narasimman M, Ory J, Bartra SS, et al. Evaluation of Bacteria in a Novel In Vitro Biofilm Model of Penile Prosthesis. J Sex Med 2022;19:1024-1031.

The Future of Penile Prosthetic Surgical Training Is Here: Design of a Hydrogel Model for Inflatable Penile Prosthetic Placement Using Modern Education Theory

BACKGROUND

There is a significant need for a non-biohazardous, educational platform to equip and maintain the surgical skills required by urology trainees and low-volume implanters for inflatable penile prosthetic (IPP) placement.

AIM

To design and develop an anatomic, hydrogel-based simulation platform for training and evaluate IPP placement using modern education theory.

METHODS

The backward design concept was used as a framework in the design and development of an IPP simulation platform. Steps included delineating requirements from a physicians' perspective, translating requirements into engineering tasks (deliverables), developing a prototype, and pilot validation. Using a combination of 3-dimensional printing and hydrogel casting, a genitourinary tract model was constructed to replicate the appropriate steps of IPP placement guided by expert feedback. Full-immersion IPP simulations were performed through both infrapubic and penoscrotal approaches by 4 expert surgeons under operative conditions. Questionnaires evaluating the simulation's realism, value as a training tool, and further recommendations were completed.

OUTCOMES

Using backward design educational pedagogy, a high-fidelity, full-procedural IPP simulation was fabricated and verified as an adequate educational tool for training and assessment.

RESULTS

An expert consensus on the anatomic landmarks, steps and substeps, instruments, and errors to be included in the model was reached using a hierarchical task analysis and was successfully translated into a prototype hydrogel model. Experts performed all appropriate steps of IPP surgery and rated the simulation highly in terms of its realism and value as a training tool. On average, experts agreed that the model could function as a training tool, assessment tool, prerequisite for IPP accreditation, and requirement before live surgery. Experts stated they would have their trainees ideally complete an average of 1.75 models before live surgical training. All experts believed an operative checklist would be an ideal assessment tool. Witthaus MW, Saba P, Melnyk R, et al. The Future of Penile Prosthetic Surgical Training Is Here: Design of a Hydrogel Model for Inflatable Penile Prosthetic Placement Using Modern Education Theory. J Sex Med 2020;17:2299-2306.

A 3-piece penile prosthesis salvage in the presence of late-onset infected hematoma: Clinical, radiological and intraoperative findings-A case report

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Penile prosthesis infection is a serious complication often managed radically.

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In selected patients, infected prosthesis can be salvaged without removal.

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Wound washout with antimicrobials and antiseptics is a key component of the management.

Introduction

Erectile dysfunction (ED) is a common health problem affecting 30% of young men worldwide. Despite the availability of non-invasive lines of management, penile prosthesis insertion is considered as a definite solution for ED. Despite strict perioperative measures, infection still complicates around 3% of penile prosthesis surgeries.

Presentation of case

This is a case of a 36-year-old male who had an infected scrotal hematoma that led to prosthesis malfunction due to the inability to locate the pump to activate and deactivate the device. Intraoperatively, the prosthesis was salvaged after hematoma evacuation and ensuring a good device functionality.

Discussion and conclusion

Infected penile prostheses are usually either removed completely with a new device insertion a few months later or exchanged at the same setting with vigorous wound washout. We suggest salvaging penile implants which are surrounded by infected hematomas in selected patients who don’t manifest systemic signs of infection. This approach will help in cost reduction and avoiding further intraoperative complications.

Simulation Training in Penile Implant Surgery: Assessment of Surgical Confidence and Knowledge With Cadaveric Laboratory Training

Introduction

Constraints on surgical resident training (work-hour mandates, shorter training programs, etc.) and availability of expert surgical educators may limit the acquisition of prosthetic surgical skills. As a result, training courses are being conducted to augment the prosthetic surgery learning experience.

Aim

To evaluate the impact of a hands-on cadaver-based teaching program on resident procedural knowledge and procedural confidence with placement of a penile prosthesis.

Main Outcome Measure

Changes in procedural knowledge and self-confidence following a focused training program on penile prosthetics.

Methods

As part of the 2017 Society of Urologic Prosthetic Surgeons and the Sexual Medicine Society of North America Annual Meeting, 31 urology residents participated in a simulation lab in prosthetic urology. The lab included didactic lectures and a hands-on cadaveric laboratory. Participants completed surveys before and after the course. Wilcoxon Signed Rank tests for matched pairs were used to compare respondents’ pre- and postcourse knowledge (% questions answered correctly) and confidence ratings. Prior implant experience was assessed.

Results

31 residents participated in this study. The majority of the participants were 4th- (41.9%) and 5th-year residents (38.7%). Participants showed a significant improvement in procedural knowledge test scores (68.8±13.4 vs 74.2 ± 13.0, P < .05) and self-reported increased median surgical confidence levels (4 vs 3, P value < .001) after completion of the cadaveric course. Subgroup analysis demonstrated that residents with prosthetic surgery experience of <10 cases benefited the most. In addition, improvement in surgical confidence levels observed was greater than the improvement in surgical knowledge. The overall cost of the simulation training course was approximately $1,483 per resident.

Conclusion

Simulation training in prosthetic surgery seems to improve surgical confidence and knowledge. Further research is needed to better understand the benefits and limitations of simulation training.

Lentz AC, Rodríguez D, Davis LG. Simulation training in penile implant surgery: Assessment of surgical confidence and knowledge with cadaveric laboratory training. Sex Med 2018;6:332–338.

Preoperative counseling and expectation management for inflatable penile prosthesis implantation

The inflatable penile prosthesis (IPP) is the gold standard surgical treatment for medical refractory erectile dysfunction (ED). While the modern IPP has enjoyed high satisfaction rates as a product of its continued innovation, reliability, and performance, patient dissatisfaction can still occur. IPP implantation restores physiologic function with cosmetic and psychological consequences, both of which place inherent emphasis on preoperative counseling and expectation management. This review aims to highlight the complex nature of such counseling and provide practitioners with a roadmap to navigate the landscape. Preoperative counseling begins with appropriate patient selection and identification of those patients who are at risk for dissatisfaction as a result of personality characteristics. The informed consent provides a natural framework to discuss the host of complications and risks that are associated with surgery, including infection, device malfunction, damage to nearby structures, and device erosion. Device selection is a nuanced process that merges patient preference with clinical factors and consideration. We address device selection through a description of cylinder construction, pump design, and reservoir placement in the context of preoperative counseling. Lastly, we draw attention to expectation management with a specific focus on possible post-operative changes to penile length and sensation as well as partner involvement. The modern IPP provides excellent results with high patient and partner satisfaction. Ultimately, satisfaction is dependent on multiple factors, but providing accurate, realistic counseling and expectation management prepares patients for the best possible outcomes.

Inflatable penile prostheses: an update

PURPOSE OF REVIEW

Since the advent of oral medication for the treatment of erectile dysfunction the disease has garnered increasing attention by both scientists and the general public alike. Coinciding with this, more patients are seeking treatment of their disease. When medical management is not successful, surgical implantation of a penile prosthesis may be considered.

RECENT FINDINGS

Because inflatable penile prostheses are vastly preferred by patients over noninflatable prostheses, this review will focus on their current use, reported durability and safety, and patient satisfaction.

SUMMARY

Inflatable penile prostheses are associated with decreasing risks of infection and device malfunction and extremely high patient and partner satisfaction rates. Because of this, inflatable penile prostheses remain a viable tertiary treatment option for erectile dysfunction.

What is new for inflatable penile prostheses?

PURPOSE OF REVIEW

Although the first inflatable penile prosthesis was introduced over 30 years ago for the treatment of erectile dysfunction, technological innovations have continually improved these penile implants since that time. This review will highlight outcomes reported in peer-reviewed literature during the past 5 years related to several recent advancements in three-piece inflatable penile prosthesis technology of interest to surgeons who implant these devices.

RECENT FINDINGS

Research findings reported during the past 5 years have been related to improvements in cylinder and pump design to provide more reliable performance with good device concealment and a normal look and feel, to ease inflation and deflation, and to reduce infection complications with inflatable prostheses.

SUMMARY

It is important for all physicians, who implant life-changing penile prosthetics, to understand the most recent advances in technology in order to best serve their patients.