Rigi10™ Malleable Penile Prosthesis
Also Known As
prosthetic penile cylinder measurement
Definition
Penile prosthesis sizing is a critical step in the surgical implantation of a penile prosthesis, a medical device designed to treat erectile dysfunction. It refers to the precise measurement and selection of the appropriate length and girth of the prosthesis components, primarily the cylinders, to ensure an optimal fit within the patient’s corporal bodies. The primary purpose of accurate penile prosthesis sizing is to achieve satisfactory erectile rigidity for sexual function, maximize patient satisfaction, and minimize the risk of postoperative complications such as pain, erosion, or device malfunction.2,3,4
The process of penile prosthesis sizing typically occurs intraoperatively after the corporal bodies have been dilated. It involves meticulous measurement of the corporal length, often from the crura proximally to the distal extent of the corpora near the glans. Surgeons may use specialized measuring tools or techniques, such as measuring the dilated space or using the length of dilators inserted. Stretched penile length, assessed during the preoperative physical examination, often serves as a guide for the realistic erectile length achievable post-implantation and can inform the sizing process.1,4
Accurate sizing ensures that the implanted cylinders are neither too short, which can lead to issues like a “floppy glans syndrome” or poor cosmetic appearance, nor too long, which can cause chronic pain, tissue erosion, or device migration.2,3,4 The selection of appropriate cylinder diameter is also important for achieving adequate rigidity and patient comfort. Some prosthetic systems include rear tip extenders that can be used to fine-tune the length of the device for a more precise fit within the corporal body. The surgeon, often in consultation with the surgical technician and medical device representative if present, confirms the measurements before the prosthesis is prepared and implanted. Post-implantation, the device is typically inflated with saline to assess the final size, positioning, and overall fit.4
Clinical Context
Penile prosthesis sizing is an integral part of the surgical treatment for erectile dysfunction (ED), particularly for patients who have not responded to or are not candidates for other therapies like oral medications, injections, or vacuum erection devices.1,4 It is a critical intraoperative step during penile prosthesis implantation surgery. The primary clinical scenario where penile prosthesis sizing is performed is during the placement of inflatable or malleable penile implants to restore erectile function.4
Patient selection for penile prosthesis implantation, and thus for the sizing procedure, involves a thorough evaluation. Candidates typically include men with organic ED from various causes such as diabetes, vascular disease, post-prostatectomy ED, or Peyronie’s disease. A comprehensive history, physical examination (including assessment of stretched penile length), and patient counseling are essential prerequisites.4 Surgeons discuss realistic expectations, including the fact that the prosthesis aims to provide rigidity for intercourse but does not typically increase penile length beyond the pre-surgical stretched length; in some cases, a slight shortening might occur.1,4 Accurate sizing is crucial for achieving these expectations.
The surgical procedure for penile prosthesis implantation involves creating incisions, typically penoscrotal or infrapubic, to access the corpora cavernosa. Once the corpora are exposed, they are dilated to create space for the prosthetic cylinders. It is at this stage that penile prosthesis sizing is performed. The surgeon meticulously measures the length of the dilated corporal bodies, from the crura proximally to the distal extent near the glans.4 This measurement dictates the length of the cylinders to be implanted. Some prosthetic systems utilize rear tip extenders (RTEs) which are added to the base of the cylinders to achieve a more precise fit and ensure the device fills the corporal space appropriately without being too long or too short.4 The goal is to select a cylinder length that will provide optimal rigidity and a natural feel when inflated (for inflatable prostheses) or in general (for malleable prostheses), while minimizing the risk of complications.
Expected outcomes are significantly influenced by appropriate sizing. Properly sized prostheses contribute to high patient satisfaction rates, which can exceed 80% with 3-piece inflatable devices.4 Complications related to improper sizing can include: if too short, a resultant “floppy glans syndrome” or poor cosmetic outcome; if too long, chronic pain, erosion of the device through tissue, or device malfunction.2,3,4 Therefore, precise intraoperative measurement and selection of prosthesis size are paramount for the clinical success of the penile implant and overall patient well-being.