(023) Mechanical Therapy After Inflatable Penile Prosthesis: A Scoping Review
Authors: Khalaf Alla K , Calopedos R , Pham R , Wang R 
Published: March 2024

Abstract

Introduction
While inflatable penile prosthesis (IPP) allows reliable axial rigidity, common complaints perceived are shorter penis and reduced glans engorgement. Pre-operative factors, such as vasculogenic erectile dysfunction (ED) or corporoglandular morphology, provide a convenient explanation. However, post-operative factors are more recently being interrogated. Post-IPP mechanical therapy protocols, like vacuum erection devices (VED), are being instituted to ameliorate these complaints. The physiological rationale is to improve perfusion of residual erectile tissues and limit cavernous fibrosis/pseudo-capsule formation. This has been hypothetically explained by upregulating endothelial nitrous oxide synthase release, decreasing hypoxia inducible factor and tissue growth factor 1. Post-IPP maximal inflation protocols similarly resulted in a more capacious and compliant tunica albuginea and capsule.

Objective
To assess the utility of post-IPP mechanical therapy in addressing common post-operative complaints and enhance prosthetic erection.

Methods
Intervention: Post-op mechanical therapy Population: Men with IPP for ED, with/without Peyronie’s disease (PD) Inclusion Criteria: Articles published in English with full-text available Search Strategy: Literature search was performed in June 2023 using Medline, PubMed, Embase and Scopus. PubMed search included “Mesh” protocols and “free text” to correctly capture study population. Articles relating to the intervention were identified with free text search searches (“VED,” “vacuum erection device,” “vacuum constriction device,” “penis pump,” “mechanical therapy,” or “rehabilitation”). Review Type & Analysis: While a systematic model was initially adopted, a scoping model was ultimately chosen given the limited available literature & variable outcome measures. In this way, we sought to identify knowledge gaps and scope of current literature to guide further studies in this field. Higher-powered analyses were not possible due to inter-study outcome measure variability.

Results
Initial search strategy retrieved 81 non-duplicate studies with 30 selected for initial screening after search limitations. Ultimately, 5 satisfied inclusion criteria after full-text review and were divided into 3 categories according to post-IPP protocol employed: Early activation (1), Maximal inflation (2,3) and VED (4,5) (Table 1). A common theme encountered was that mechanical therapy improved post-IPP penile length and girth, compared to immediate post-operative measurements. Only one study used a control group who had their device activated for the first time after 4 weeks. The intervention employed in this study was device activation immediately after surgery, left 80% inflated and deflated at 3 weeks, then full erection at night for 3 further weeks. Compared to the control, at maximum inflation, penile length mean was 3.28cm longer and circumference was 1cm greater. In each of these studies, the differences reported were statistically significant. This was also associated with an increased number of pumps required to achieve full inflation over time, irrespective of mechanical protocol used. Articles that reported IIEF-5 and EDITS scores demonstrated a statistically significant improvement over time with post-op intervention.

Conclusions
Within limits of the included studies, post-implantation mechanical therapy appears to be useful in improving penile dimensions and patient satisfaction over time. The correlation with increasing number of pumps implies that compliance of the tunica albuginea and residual cavernous tissue may play a role in the pathogenesis of shorter penis post-IPP. Further high-powered studies in this area are warranted.

Disclosure
No.