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Reservoir Placement for Three-Piece Inflatable Penile Prostheses

The reservoir is the most surgically consequential component of the 3-piece IPP. Cylinder placement and pump placement are predictable and well-standardized; reservoir placement involves navigating through anatomy that has often been surgically altered (prostatectomy, cystectomy, transplant, hernia mesh, C-section) and offers the most common route to serious complications — bladder injury, bowel injury, vascular injury, and reservoir herniation.[1][2]

This article covers the three reservoir locations in contemporary use: space of Retzius (classic / submuscular-adjacent), ectopic submuscular (high submuscular, HSM), and ectopic subfascial / pre-peritoneal. It also addresses the decision framework for choosing between them, the 2-piece option as an anatomic escape hatch, and the specific complications of each location.

Anatomic Review​

The space of Retzius (prevesical space)​

The preperitoneal space anterior to the bladder, bounded by:

  • Anteriorly: pubic bone and posterior surface of the rectus abdominis with the transversalis fascia
  • Posteriorly: bladder and pelvic peritoneum
  • Laterally: obturator internus and the lateral umbilical ligaments
  • Inferiorly: endopelvic fascia and puboprostatic ligaments (in men)
  • Superiorly: open to the preperitoneal fat of the anterior abdominal wall

This is the native space for 3-piece reservoir placement. It accepts a 65–100 mL reservoir with minimal resistance when the anatomy is virgin.

The transversalis fascia​

The entry point. Accessed from the penoscrotal approach by passing a finger or reservoir introducer through the external inguinal ring, along the iliopubic tract, and through the transversalis fascia into the space of Retzius. In an infrapubic approach, the transversalis fascia is entered directly under vision.

Why "altered anatomy" is the central problem​

  • Radical prostatectomy obliterates much of the inferior space of Retzius; the anterior-to-bladder plane is scarred
  • Radical cystectomy with ileal conduit or neobladder completely eliminates the native reservoir space
  • Renal transplant places a transplanted kidney with its vascular pedicle in the iliac fossa, creating a reservoir no-go zone
  • Prior pelvic radiation scars the Retzius plane and elevates complication rates regardless of approach
  • Hernia mesh — particularly bilateral TAPP or TEP repairs — creates a mesh-anchored barrier across the space
  • Prior C-section (multiple) — less often problematic, but can alter the preperitoneal plane

Reservoir Location Options​

1. Space of Retzius (SoR) — the traditional location​

The classic location, taught as the default. The reservoir sits anterior to the bladder, behind the rectus abdominis, conforming to the space naturally.

Volume: 65–100 mL filled intraoperatively (most commonly 65 or 75 mL). Underfilling avoids autoinflation; overfilling risks reservoir-induced bladder compression.

Access technique (penoscrotal approach — blind):

  1. Identify the external inguinal ring by palpation with an index finger from inside the scrotal wound (or through a counter-incision in some protocols).
  2. Advance the finger cephalad through the ring, along the inguinal canal.
  3. Perforate the transversalis fascia with controlled finger pressure or a Metzenbaum scissors tip — the transversalis gives way with a characteristic "pop."
  4. Sweep the space of Retzius bluntly to confirm a soft, empty space — no adhesions, no firm tissue, no pulsation. Vascular structures, mesh, or bowel adhesions are absolute contraindications to proceeding.
  5. Fill the Foley to drain — the bladder is empty for reservoir placement.
  6. Pass the reservoir introducer (Coloplast or Boston Scientific proprietary, or a nasal speculum / Yankauer for manual technique) and advance the reservoir into the space.
  7. Fill with the appropriate volume (per manufacturer and device).
  8. Confirm the reservoir sits dependently behind the pubic bone; no herniation, no abdominal wall contour abnormality, no compression of the Foley balloon.

Access technique (infrapubic approach — direct):

The transversalis fascia is incised under vision after exposure of the pubic symphysis and rectus insertion. The reservoir is placed directly into the space of Retzius under visual control.

Complications specific to SoR placement:

  • Bladder injury — classically presents as hematuria and inability to maintain reservoir fill volume; evaluated with cystoscopy and (if confirmed) requires reservoir explantation, bladder repair, and deferred replacement
  • Bowel injury — most often the dome of the bladder bowel or small bowel adhesion; catastrophic if missed; requires laparotomy
  • Vascular injury — external iliac or inferior epigastric vessels; rare but can be fatal
  • Reservoir herniation — into the scrotum or inguinal canal, particularly in patients with a patent processus vaginalis

2. High Submuscular (HSM) / Ectopic Submuscular — the modern workhorse for altered anatomy​

Developed by Morey and Cefalu and widely adopted since 2013, HSM placement puts the reservoir between the rectus abdominis and the posterior rectus sheath, above the arcuate line — entirely away from the space of Retzius.[3][4]

The arcuate line (semicircular line of Douglas) is critical anatomy. Below it, the posterior rectus sheath is absent — the rectus lies directly on the transversalis fascia and peritoneum. Above it, the rectus has a defined posterior sheath. Reservoir placement above the arcuate line is submuscular; placement below it is preperitoneal and carries peritoneal/bowel risk.

Technique:

  1. From the penoscrotal (or infrapubic) incision, identify the external inguinal ring.
  2. Advance the reservoir introducer through the ring, hug the abdominal wall, and pass the introducer cephalad — above the inguinal ligament.
  3. Bluntly dissect cephalad to a position above the arcuate line (typically 8–12 cm above the pubic symphysis — roughly at or above the level of the umbilicus).
  4. The dissection plane is between the rectus muscle and its posterior sheath — confirmed by the "tent" feel of the rectus as it is lifted off the posterior sheath.
  5. Place the reservoir in this high submuscular pocket.
  6. Confirm no herniation, no palpable bulge below the arcuate line, and no communication with the space of Retzius.

Advantages:

  • Avoids space of Retzius entirely — ideal for post-prostatectomy, post-cystectomy, transplant, hernia mesh, multiple-C-section patients
  • Low bladder/bowel injury risk — the dissection is entirely above the peritoneal reflection
  • Autoinflation rates comparable to SoR — some series report lower rates with HSM due to tighter pocket fit
  • Easier revision — the HSM pocket is more accessible than the scarred SoR for future surgery

Disadvantages:

  • Palpable or visible reservoir in thin patients — a visible bulge below the rib cage is occasionally reported
  • Requires more cephalad dissection — occasionally difficult in obese patients with deep scrotal anatomy
  • Mesh patients — even HSM can be complicated by mesh extending above the inguinal ring

3. Subfascial / preperitoneal ectopic placement​

An intermediate option: the reservoir is placed below the transversalis fascia but away from the bladder — often lateral to the midline, in the preperitoneal fat. Less commonly used than HSM in contemporary practice but described in the literature as an option for selected anatomies.

Decision Framework: Which Reservoir Location?​

Anatomic scenarioPreferred location
Virgin abdomen, primary implantSpace of Retzius
Prior radical prostatectomyHSM (or 2-piece)
Prior radical cystectomy / neobladderHSM (or 2-piece)
Renal transplantHSM (or 2-piece; contralateral side from graft)
Bilateral inguinal hernia meshHSM (if pocket developable above mesh) or 2-piece
Prior pelvic radiationHSM preferred
Obese patient, virgin abdomenSoR (HSM may be challenging from below)
Prior multiple C-sectionsSoR usually feasible; HSM as backup
Thin patient, cosmetic concernSoR (HSM may be palpable)
Unknown anatomy, aborted SoR attemptHSM as salvage

The 2-Piece Alternative​

When the abdominal anatomy is so altered that neither SoR nor HSM placement is safe, the 2-piece IPP eliminates the separate reservoir entirely:

  • AMS Ambicor — fluid reservoir is integrated into the rear-tip of the cylinders
  • Rigicon Infla10 2-piece — similar integrated-reservoir concept

Advantages: No abdominal reservoir; entire device lives between penis and scrotum; avoids all reservoir-placement complications.

Disadvantages: Less rigidity than 3-piece; less complete flaccidity; shorter expansion range.

The 2-piece is the right answer for the patient whose anatomy simply cannot accept any abdominal reservoir — extensive mesh, pelvic exenteration, solid-organ transplant with complicated vascular anatomy, or prior reservoir complications in multiple locations. See implant models for device specifics.

Reservoir Fill Volume​

Standard practice is to underfill relative to maximum to avoid autoinflation. General principles:

  • 65 mL reservoir filled to 60 mL — most common
  • 75 mL reservoir filled to 65–70 mL
  • 100 mL reservoir filled to 85–90 mL
  • Coloplast Titan Cloverleaf reservoir (low-profile, bellows-shaped for HSM) filled per manufacturer guidance

Check cycling function after fill and before closure. A reservoir that does not deflate completely suggests a kink in the tubing, mispositioning of the reservoir in a cramped pocket, or an inflated pump seized against scar tissue.

Reservoir-Specific Complications​

Autoinflation​

Mechanism: Pocket is too tight or the reservoir is positioned against a rigid structure that compresses it during Valsalva, coughing, or lifting. Fluid is displaced into the cylinders without the patient activating the pump.

Prevention: Adequate pocket development; appropriate underfill; careful positioning dependent on gravity.

Treatment: Often requires revision with pocket enlargement or reservoir relocation; modern "lock-out valve" pumps (present in current AMS and Coloplast pumps) substantially reduce autoinflation rates.[5]

Reservoir herniation​

Mechanism: Reservoir migrates from SoR through the inguinal canal into the scrotum, creating a painful, cosmetically abnormal scrotal mass.

Prevention: Careful preoperative assessment for patent processus vaginalis; use of HSM in patients with large patulous external rings.

Treatment: Revision surgery to relocate reservoir, often to HSM, and repair of the internal ring.

Bladder injury​

Presentation: Hematuria, inability to maintain reservoir fill volume (fluid drains into the bladder), failure of the device to cycle properly. May present immediately or after the reservoir erodes through a scarred bladder wall weeks to months postop.

Workup: Cystoscopy is the gold standard. CT cystogram is useful for suspected delayed erosion.

Treatment: Explantation of the reservoir, cystorrhaphy, period of catheter drainage (10–14 days), and delayed reimplantation (typically 3–6 months).

Vascular injury​

Rare but reported. External iliac vessels, inferior epigastric vessels, and obturator vessels are at risk in blind SoR placement in altered anatomy. Recognition requires a high index of suspicion; immediate hemodynamic changes or an expanding abdominal hematoma mandate laparotomy.

Bowel injury​

Nearly always a catastrophic complication, most common in patients with extensive prior abdominal surgery when SoR is attempted despite relative contraindication. Recognition may be delayed by days; early postoperative sepsis, ileus, or acute abdomen demands CT and likely laparotomy. This complication is the single strongest argument for HSM as the default in altered abdominal anatomy.

Reservoir migration​

A reservoir that starts in the correct position but migrates into an adjacent space (retroperitoneum, scrotum, paravesical space) due to an inadequately developed pocket or patulous entry defect. Can present immediately or years later.

Specific Technical Points​

Foley management during placement​

Drain the Foley before reservoir placement. A full bladder is easier to injure and makes the SoR feel different on palpation. After reservoir placement, the Foley is often left overnight and removed the next morning.

Fill with saline, not water​

Sterile saline is standard. Sterile water is used in some rare protocols but is not standard. Contrast can be added in patients where postoperative imaging verification of reservoir position is anticipated, but this is unusual.

Confirm no communication with the bladder​

After fill, palpate the Foley (if in place). A reservoir compressing the bladder or adjacent to a bladder injury can alter Foley feel. Cycle the device 2–3 times — confirm full inflation and full deflation before closure.

The one-incision vs. two-incision question​

A "one-incision" approach is possible through either PS or IP: all three components are placed through the single primary incision. A "two-incision" approach uses a separate low midline or inguinal counter-incision specifically for direct reservoir placement under vision — this is standard practice in many IP protocols and in complex SoR cases.

See Also​

References​

1. Levine LA, Hoeh MP. Review of penile prosthetic reservoir: complications and presentation of a modified reservoir placement technique. J Sex Med. 2012;9(10):2759–69. doi:10.1111/j.1743-6109.2012.02855.x

2. Sadeghi-Nejad H, Ilbeigi P, Wilson SK, et al. Multi-institutional outcome study on the efficacy of closed-suction drainage of the scrotum in three-piece inflatable penile prosthesis surgery. Int J Impot Res. 2005;17(6):535–8. doi:10.1038/sj.ijir.3901354

3. Morey AF, Cefalu CA, Hudak SJ. High submuscular placement of urologic prosthetic balloons and reservoirs via transscrotal approach. J Sex Med. 2013;10(2):603–10. doi:10.1111/j.1743-6109.2012.02991.x

4. Pagano MJ, Gonzalez-Cadavid N, Valenzuela RJ. Ectopic reservoir placement for inflatable penile prostheses: modifications of the high submuscular technique. Int J Impot Res. 2019;31(4):291–297. doi:10.1038/s41443-018-0101-z

5. Wilson SK, Henry GD, Delk JR Jr, Cleves MA. The mentor Alpha 1 penile prosthesis with reservoir lock-out valve: effective prevention of auto-inflation with improved capability for ectopic reservoir placement. J Urol. 2002;168(4 Pt 1):1475–8. doi:10.1097/01.ju.0000030113.95075.5f