Advancements in ectopic reservoir placement for inflatable penile prostheses

Introduction Traditional reservoir placement (RP) into the space of Retzius during three-piece inflatable penile prosthesis implantation has been associated with serious bladder, iliac vessel, and bowel complications, encouraging the development of "ectopic" RP methods.Objectives In this study we sought to document an up-to-date, comprehensive analysis of ectopic RP techniques regarding both patient satisfaction and clinical complications.Methods A PubMed, Ovid MEDLINE, and Cochrane Library literature search of English language articles from 1966 to 2023 with keywords "inflatable," "penile prosthesis," "reservoir," and "placement" gave 179 publications, 70 of which were included in a comprehensive chronology and investigation after review. Overall, 12 retrospective studies detailing 9 ectopic RP techniques were compared for discussion.Results Sufficient data for comparison were found for 9 ectopic RP methods: posterior/anterior to transversalis fascia (PTF/ATF); high submuscular (HSM); HSM "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 with the use of ectopic RP techniques: 2 bladder perforations on implantation with PTF RP, a delayed bowel obstruction with HSM RP, and a colonic injury in a patient with a history of colon surgery with LR RP. Generally, herniation is the most relevant clinical complication in ectopic RP. At the time of this review there was no reported herniation with LR, SEO, LSM w/ TFF, or MSMR, likely due to fixation steps and/or reinforced spaces. Regarding patient satisfaction, HSM, HSM-FST, and LSM w/ TFF had similarly high rates of patient satisfaction while other techniques had no patient satisfaction data available. Importantly, reservoir palpability/visibility relates directly to patient satisfaction. Levels of palpability and/or visibility were reported in patients who underwent PTF/ATF, HSM, HSM-FST, SEO, and LSM w/ TFF, whereas no palpability was reported in patients who underwent LR, DVT, and MSMR.Conclusion Proper comparison of ectopic methods is not possible without standardized patient surveys, consistent complication reporting, and larger sample sizes, indicating the need for a large, prospective, multisurgeon trial.