Figure. Placement of reservoir into inguinal ring.

The 3-piece inflatable penile prosthesis (IPP) has remained an effective therapy for medically refractory erectile dysfunction for 50 years. Reservoir placement (RP) is considered one of the most difficult steps of implantation, challenging even the skilled surgeon and potentially begetting dire complications. Traditional placement into the space of Retzius has been associated with bladder perforation, iliac vasculature injury/compression, small-bowel erosion/obstruction, erosion into an ileal conduit/neobladder, herniation, and enterocutaneous fistula.¹ These complications are known to occur more frequently in patients with pelvic anatomy complicated by previous surgery, radiation, or anatomical anomaly. In an effort to avoid such complications, “ectopic” RP outside the peritoneal cavity and away from important pelvic anatomy, anterior to transversalis fascia and posterior to the abdominal musculature, was first described by Wilson et al in 2002.² Innovation in ectopic techniques has boomed over the last 20 years as new surgical methodology has been enhanced, and made possible, by the 1998 introduction of the lockout valve and 2010 release of flat reservoirs, allowing implantation without autoinflation and particularly visible reservoirs, respectively.³

Of the ectopic techniques, one of the first and most well documented is high submuscular RP (HSM). Introduced by Morey et al in 2013, HSM implants the reservoir between the transversalis fascia and rectus abdominus muscle utilizing a pediatric Deaver retractor and Foerster lung-grasping clamp to advance the reservoir cephalad via a transscrotal approach.⁴ Complications of this initial technique included intraperitoneal placement, reservoir visibility/palpability, bowel obstruction, reservoir migration, and reservoir herniation.⁵ Although introduction of the refined “5-step” technique in 2020 effectively lessened the rate of deep pelvic injuries, the issue of herniation, often requiring surgical revision, remains persistent.⁶ It is important to note that although HSM is not the only ectopic technique associated with herniation and palpability issues, its long history has inspired implanters to develop new RP strategies utilizing reinforced spaces and/or additional fixation steps in order to avoid such complications.

One such recent advancement in ectopic RP is the low submuscular (LSM) with transfascial fixation technique (TFF). First described in patients undergoing pressure-regulating balloon placement for artificial urinary sphincter implantation, LSM with TFF places the reservoir inferiorly in the abdominal wall to prevent visibility/palpability while the fixation step prevents herniation.^7,8 Approaching via either a penoscrotal or infrapubic incision, an S-retractor is placed in the eternal inguinal ring to elevate the fascia. A space inside the ring below the rectus muscle and above the transverse fascia is then developed using blunt dissection or a ring forceps. Next, the lateral aspect of the inguinal ring is grasped with an Allis clamp while a right angle is passed in an out-to-in fashion through either the lateral or medial aspect of the fascia. The reservoir tubing is then brought through the fascia and the reservoir placed underneath the rectus muscle and filled with normal saline (see Figure).

The first series of 31 patients undergoing IPP placement or revision with LSM with TFF RP was published in 2022.⁸ Of the 26 patients undergoing follow-up survey, an overall penile implant satisfaction rate of 4.1/5 was reported with 8 (26%) able to palpate the reservoir, 4 (15.4%) able to see the reservoir, and 1 (3.8%) endorsing minimal severity pain from the reservoir. Importantly, overall satisfaction with reservoir concealment was 4.5/5, no patients reported bother from the reservoir, and 96.2% would recommend IPP surgery. Additionally, no surgical revisions were required and there were no surgical complications such as bowel obstruction, herniation, bladder erosion, or vascular injury. These favorable data suggest this methodology can be used in almost all patients, but it is particularly indicated for those with complicated pelvic anatomy and/or a violated space of Retzius.

Overall, LSM with TFF is a safe, reliable, and effective ectopic RP technique that successfully addresses some of the most pressing IPP implantation issues to date: herniation, patient satisfaction, and concealment. Although this series is limited by small sample size, we look forward to continuing our investigation of this promising technique.