Mechanism of Penile Prosthesis Induced Urethral Stricture: Treatment and Prevention

The advent of phosphodiesterase type 5 inhibitor has revolutionized the management of erectile dysfunction (ED). Since the introduction of sildenafil citrate in 1998, oral systemic therapy has become the first line therapy for men with ED. However, oral pharmacotherapy often fails in patients with severe diabetes, radical prostatectomy, Peyronie’s disease, and severe penile fibrosis. These patients may select other therapies such as penile injection therapy or a vacuum erection device. When oral and injectable therapies fail to produce satisfactory results, implantation of a penile prosthesis is the last strategy which has demonstrated the highest level of satisfaction among treatments for ED [1,2]. Penile implants include malleable (semi-rigid) and inflatable (twoor three-piece) types. Most patients prefer the three-piece inflatable devices because it most closely approaches the functioning penis with respect to flaccidity and erection. Three-piece prostheses consist of paired corporal cylinders, a scrotal pump, and a large volume reservoir implanted into the prevesical or retropubic space (Fig. 1). Currently available three-piece devices include the Coloplast Titan, Coloplast Titan Narrow Base, the AMS Ultrex, the AMS 700 CX, AMS 700 CXM and the AMS 700 CXR. A major difference is whether connecting tubing between cylinders and pump has been made on production line or not. The inflatable prostheses are usually inserted via a penoscrotal or an infrapubic approach. The advantage of the infrapubic approach is the placement of the reservoir under direct vision. However, this approach limits to expose the corpora cavernosa and may damage the dorsal nerve, especially during revision procedures. The penoscrotal or transverse scrotal approach allows to securely placing the pump in the scrotum and the skin in the prepubic area is not violated, but the reservoir has to be placed blindly through the inguinal canal which may injury the iliac vessels [3]. In the past, the implantation of a penile prosthesis was often associated with high complication rate such as infection, persistent pain, cavernous perforation, mechanical failure, malposition, erosion into the bladder, urethra and bowel, and gangrene [4,5]. In recent years, the use of antibiotic impregnated or hydrophilic-coated prosthesis and proper antibiotic prophylaxis against Gram-positive and Gram-negative bacteria has significantly reduced the complication rates. The two main complications of penile prosthesis implantation are mechanical failures and infection. The technical improvements result in mechanical failure rates of less than 5% at 5-year follow-up [6,7], and infection rates range from 1 to 4% [8,9].