All Products
Also known as
High submuscular reservoir placement, Submuscular reservoir placement, Alternative reservoir placement, Nontraditional reservoir placement, Abdominal wall reservoir placement, Ectopic IPP reservoir placement
Definition
Reservoir malposition is a complication of three-piece inflatable penile prosthesis (IPP) surgery in which the fluid reservoir lies in, or moves into, an unintended position. Acute problems typically arise from direct perforation at the time of reservoir placement, whereas delayed complications are more often related to reservoir or tubing migration, erosion, fistulation, obstruction or herniation.1 Reported reservoir complications include inguinal herniation, erosion into the bladder or bowel, intraperitoneal placement with subsequent injury to the ureter or bowel, vascular injury and autoinflation.2 Migration of the reservoir through the inguinal canal is rare, with reported frequencies of 0.09% to 1.2% after placement in the space of Retzius and 1.4% after other reservoir placements.3 Malposition can also be present from the start: in a cadaver model of blind high submuscular placement, reservoirs ended up in variable anatomical layers, including within or immediately superficial to the peritoneal cavity, without the surgeon recognising it.4 Reservoir complications are uncommon but may require revision surgery.5
Clinical Context
Herniation occurs when the space created through the inguinal ring is large enough that, with increased abdominal pressure, the reservoir completely or partly herniates through the external ring; it usually does not affect device function but may cause discomfort that warrants correction.6 Patients with a herniated reservoir have presented with sharp pain or a palpable scrotal mass, and haematuria, voiding symptoms or bowel dysfunction may indicate intraperitoneal placement and visceral injury.7 A retained, decommissioned reservoir has eroded into the bladder 15 years after placement, presenting with gross haematuria, recurrent urinary tract infections and worsening lower urinary tract symptoms.8 A reservoir compressing the pelvic veins can cause leg swelling and deep venous thrombosis within days of surgery.9 Autoinflation, the unwanted transfer of fluid from the reservoir into the cylinders, often occurs early after surgery with increased abdominal pressure and is thought to result from the tissue capsule that usually forms around the reservoir within 3 months.10 Palpability needs interpretation, because subtle palpability of a submuscular reservoir may be normal, especially in a thin abdominal wall.6
Computed tomography is readily available and rapid and is the diagnostic modality of choice when prosthetic complications present; magnetic resonance imaging gives anatomical detail but is less readily used.6 Imaging shows where a migrated reservoir lies in relation to the external ring and so guides the surgical approach.6 A low threshold for contrast-enhanced CT of the abdomen and pelvis is advised in patients with risk factors or unexplained postoperative deterioration.1 Apparent autoinflation can rarely be mimicked by high-flow priapism from an arteriocavernosal fistula, which has been identified with ultrasound or MRI.11
An incidental herniation without adjacent tissue damage in an asymptomatic patient does not require intervention, whereas a malpositioned reservoir that threatens adjacent structures can be surgically repositioned.6 Described repairs for herniation include a purse-string suture to support the inguinal ring or higher placement within the inguinal canal through an inguinal incision.3 Severe autoinflation may require a capsulotomy to free and realign the reservoir.3 Delayed bowel perforation, erosion or fistulation usually requires explantation of the prosthetic material together with bowel repair or resection,1 and after bladder injury or erosion the reservoir can be reimplanted on the contralateral side or in an ectopic location.3 Venous compression has been managed by repositioning the reservoir followed by venous thrombectomy.9
Prevention relies on catheterising and draining the bladder before placement, a back-pressure test after filling and reservoirs with lockout valves designed to prevent autoinflation.7,12 A counter-incision may reduce the risk of improper location, folding and migration.13 On imaging after transinguinal placement, final reservoir position varies, yet reservoir-related complications remained rare.14