(393) Advancements in Ectopic Reservoir Placement for Inflatable Penile Prostheses
Authors: Wright N , Khera M 
Published: February 2024

Abstract

Introduction
Traditional reservoir placement (RP) into the space of Retzius (SOR) during three-piece inflatable penile prosthesis (IPP) implantation has been associated with dire bladder, iliac vessel, and bowel complications, leading many surgeons to pioneer alternative, “ectopic” methods. Despite the extensive literature on ectopic RP, there is little direct comparison of these techniques to one another with respect to efficacy and/or safety.

Objective
To document an up-to-date, comprehensive analysis of ectopic RP techniques regarding both patient satisfaction and clinical complications.

Methods
A PubMed literature search of English language articles from 1986-2023 with keywords “inflatable,” “penile prosthesis,” “reservoir,” and “placement” gave 113 publications, 62 of which were included in a comprehensive chronology and investigation after abstract review (last updated 7/3/2023). Analysis of published data yielded 12 retrospective studies detailing 8 ectopic RP techniques that were included for comparison (Table 1).

Results
Of the ectopic RP methods explored, 8 have sufficient data for comparison: posterior & anterior to transversalis fascia (PTF & ATF); high submuscular (HSM); high submuscular ‘Five-Step’ technique (HSM-FST); lateral retroperitoneal (LR); sub-external oblique (SEO); direct vision, transfascial (DVT); low submuscular with transfascial fixation (LSM w/ TFF); and midline submuscular reservoir (MSMR). Although rare, serious complications have occurred in ectopic RP: PTF reports 2 bladder perforations on implantation, HSM reports a delayed bowel obstruction, and LR reports a colonic injury in a patient with a history of colon surgery. When unsure, a counterincision can be used to lower risk of violating fascial planes and causing visceral injury. Aside from these cases, herniation is the most relevant clinical complication in ectopic RP. There is no reported herniation with LR, SEO, LSM w/ TFF, or MSMR, likely due to fixation steps and/or reinforced spaces. Reports of newer ectopic strategies often have small sample sizes and limited follow-up which potentially under- or overestimate complication rates, indicating a need for more robust longitudinal study. In regards to patient satisfaction, HSM, HSM-FST, and LSM w/ TFF have high and similar rates of patient satisfaction while other techniques do not provide data. In addition to increased rates of reporting, a validated patient survey is needed to standardize comparison of efficacy and patient perspective between different techniques. Importantly, reservoir palpability/visibility relates directly to patient satisfaction. PTF & ATF, HSM, HSM-FST, SEO, and LSM w/ TFF report levels of palpability and/or visibility while LR, DVT, and MSMR have no reported palpability.

Conclusions
Without standardized patient surveys, consistency in complication reporting, and larger sample sizes, it is impossible to properly compare different ectopic methods. The prosthetic community needs a large, prospective, multisurgeon study comparing ectopic methods to each other, not just to SOR. Until such data is available, implanters should assess different methods in regards to their unique benefit and complication profiles, becoming experts in those that can best serve their patient population.

Disclosure
Any of the authors act as a consultant, employee or shareholder of an industry for: Consultant: AbbVie, Marius, Tolmar, Endo, Petros, Boston Scientific, Coloplast // Investor: Sprout.