Tips and tricks on penile prosthesis implantation in the fibrosed penis

Fibrosed penis (corporal fibrosis) is commonly encountered in males with severe Peyronie’s disease (PD), those who had priapism, and in cases following explant of prior infected penile prosthesis implants. This condition often causes loss of penile size and is invariably associated with considerable psychosexual distress to the patients and their partners. Furthermore, penile prosthesis implantation (PPI) can often be wrought with technical challenges and intraoperative and postoperative complications. Preoperative optimization of the corporal tissue with the use of penile vacuum therapy and erectogenic drugs should be advocated to improve the penile size and “soften” the underlying fibrotic process. Various surgical instruments have been designed to deal with corporal fibrosis, and the use of a “narrower” cylinder can often be useful in advanced fibrotic cases. Adherence to safe surgical principles with attention to detail is critical to ensuring optimal PPI. Judicious postoperative penile rehabilitation can aid the overall penile esthetic following PPI and improve the overall penile size. The following article provides an overview of the surgical strategies, including tips and tricks on PPI in the fibrosed penis. Fibrosed penis (corporal fibrosis) is commonly encountered in males with severe PD, those who had priapism, and in cases following explant of prior infected penile prosthesis implants.1,2 The underlying pathogenesis for corporal fibrosis is likely related to corporal hypoxia and ensuing tissue ischemia.3 Males with PD often report erectile dysfunction secondary to veno-occlusive dysfunction from the underlying tunical disease process, although the literature has highlighted that arterial occlusive disease can occur in those with advanced PD.4,5 Studies have shown that corporal fibrosis can occur within 6 h of ischemic (low flow) priapism due to venous congestion, and histopathological section confirmed the presence of cavernosal smooth muscle necrosis.6 In some cases, repetitive and incorrect intracavernous injections can cause intracavernosal fibrosis too.1 In explant of infected penile prosthesis implant, ongoing tissue inflammation and ensuing necrosis, coupled with the absence of corporal blood flow, resulted in significant corporal fibrosis and subsequent penile size loss.7 The presence of the fibrosed penis and ensuing penile size loss is a devastating condition and is associated with considerable psychosexual distress to the patients (and their partners).8,9 Studies have highlighted this adverse impact beyond sexual function, as some men complained of difficulty voiding (short penis), social withdrawal, and lost productivity.9,10 In many instances, these men have severe medically refractory erectile dysfunction, for whom PPI remains the only definitive treatment option. Significant corporal fibrosis can pose a substantial technical challenge to PPI surgery in terms of corporal dilation and a higher risk of prosthesis infection and malfunction.1,11–14 The following article provides an overview of the strategies, including tips and tricks on PPI in the fibrosed penis. A literature search on relevant English-only articles pertaining to penile prostheses was undertaken in PubMed and EMBASE databases, and the following terms were included in the search for articles of interest: “penile prosthesis implant”, “cylinder”, “complication”, and “fibrotic corpora”. A detailed surgical description related to the actual prosthetic surgery was not intended in this review, nor was a detailed description of various penile prosthetic-related complications. A full Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol was not adopted for this narrative review. An overview of the surgical strategies, including tips and tricks to handle cylinder placement in corporal fibrosis, is presented in Figure 1.Figure 1: Tips and tricks on penile prosthesis implantation in the fibrosed penis. This algorithm is flexible. Surgeons need to understand the nuances of surgical strategies and each tip and tricks should be individualized based on the specific encounter (different types of fibrosed penis). CT: computed tomography; MRI: magnetic resonance imaging; PDE5i: phosphodiesterase type 5 inhibitor.PREOPERATIVE STRATEGIES Since the underlying corporal fibrosis causes penile size loss and poses challenges in corporal dilation during PPI, various preoperative strategies have been deployed to improve the penile size and “soften” the underlying fibrosis process. The vacuum pump has been utilized to “stretch” the underlying corporal fibrosis and can be an effective penile rehabilitation tool, especially in men with erectile dysfunction following post-prostatectomy.15 Vacuum erection device (VED) uses negative pressure to distend the corporal sinusoids and to increase blood inflow to the penis with corporal oxygenation. The animal model confirmed that a vacuum pump provides beneficial effects through various anti-hypoxia, anti-fibrosis, and anti-apoptosis mechanisms.16 This positive effect of vacuum device therapy in preserving penile length has been reported in those following priapism and infected PP cases too.17,18 Various pro-erectile medications such as phosphodiesterase type 5 inhibitors (PDE5is) and pentoxifylline have been used to promote corporal blood flow as a form of penile rehabilitation. These medications aim to target and upregulate the nitric oxide/cyclic guanosine monophosphate pathway by inhibiting collagen synthesis and promoting the replication of smooth muscle cells, which theoretically could prevent or reverse fibrosis.19–21 However, its actual clinical utility is likely limited in those with severe corporal fibrosis and coexisting erectile dysfunction. SURGICAL TOOLS FOR CORPORAL DILATION AND/OR EXCISION Multiple tools have been invented to assist the surgeon in dilating or creating a space in a fibrotic corpora cavernosa, including sharp dissection with Metzenbaum scissors, serial corporal dilation using Hegar or Brooks dilators, cavernotomes, or specialized cutting dilators. Corporal dilation in the setting of corporal fibrosis often requires meticulous and safe techniques with an increased effort to break through the effect of the fibrotic plaque(s) and a higher likelihood of corporal perforation.1 Various cavernotomes, such as Rossello-Carrion dilators (Coloplast, Minneapolis, MN, USA), Uramix Mooreville Dilator (Uramix, Lansdowne, PA, USA), and Freeman Kaye or Gourney scissors or more recently redesigned as the Wilson backwards cutting scissors (Uramix, Lansdowne, PA, USA), have been marketed and used to “incise” and dilate the fibrosed corporal tissue.1,2,22 The key operative considerations are careful and serial increments of dilation, staying away from the urethra, and being mindful of tunical perforation. The aim is to create a sufficiently large corporal tunnel to accommodate the appropriate prosthetic cylinder size. More “aggressive” techniques have been described in severe corporal fibrosis, such as complete excavation of the fibrosed corporal tissue, extracorporal transseptal, and the use of endoscopic instruments for optical corporotomy and transcorporal resection. Extensive excision of the scar usually involves a long corporotomy with dissection and excision of the fibrosed corporal tissue to create a space where the implant can be placed.23,24 Shaeer’s technique involves direct visualization using an endoscopic tool to remove the fibrotic corporal tissue and create a sufficient tunnel for the cylinders to be placed.25,26 For patients with a palpable penile plaque in addition to a fibrosed corpora, incision and partial excision of the plaque followed by graft reconstruction could improve the penile cosmesis and increase the penile size.1,8 In cases with loss of penile size, complex penile reconstruction can be performed with various techniques such as modified sliding technique (MoST) and multiple slice technique (MuST) or multiple-slit technique with or without graft placement.2,8 The use of various “sliding techniques” during graft reconstruction should be adopted with caution and only be undertaken after proper informed consent regarding potential benefits and by surgeons who are well-versed in complex penile reconstruction. CYLINDER SIZE SELECTION AND USE OF GRAFTING The appropriate cylinder size is selected based on the maximum corporal length measurement, with the aim of a larger cylinder with shorter rear tip extenders. The recommended cavernosal dilation is 12 mm for standard IPP cylinder insertion and 10 mm if a smaller diameter or narrow-base device is utilized. In cases of severe corporal fibrosis, a downsized implant can be selected. Although these smaller implants may cause a loss of penile length and girth, they can expand the tunnel over time and allow for the implantation of a regular-sized prosthesis if needed in the future.27 The AMS 700 CXR or Coloplast Titan narrow-based cylinder can be used if corporal dilation is