Figure 1. Treatment algorithm when intraoperative artificial erection (AE) demonstrates curvature prior to placement of inflatable penile prosthesis (IPP).

Figure 2. Preoperative photos from revision case demonstrating 75-degree right curvature (A) and 15-degree dorsal curvature (B). The patient’s device was downsized to correct curvature with 5-degree right curvature (C) and no dorsal curvature (D).

This year marks the 50th anniversary of the inflatable penile prosthesis (IPP), a device that has revolutionized the treatment of erectile dysfunction (ED). In the properly selected patient, patient and partner satisfaction are high. Reasons for dissatisfaction include complications (infection, erosion, device failure, intraoperative complication), prolonged pain, perceived loss of penile length, improper sizing, and device malfunction.¹ Nearly 75% of IPP devices are placed by a surgeon who performs fewer than 5 prosthesis surgeries per year.² While the steps of IPP surgery are relatively simple, each case can present unique challenges due to patient anatomy, previous surgery, or Peyronie’s disease (PD). As such, prosthetic surgeons should be prepared to troubleshoot several common intraoperative scenarios including the presence of asymmetric corporal measurements (ACM).

The etiology of ACM includes measuring error, iatrogenic injury, and true anatomical asymmetry. Prosthetic surgeons should troubleshoot in a stepwise approach, the first step being to remeasure after redilation using a fixed point to record the proximal and distal measurements. Second, rule out urethral injury or distal perforation with corporal irrigation. Third, assess for crossover by inserting a pair of corporal dilators both proximally and distally. Lastly, evaluate for proximal perforation with the goal post test. If these steps have been performed and asymmetry remains, the question remains how to manage ACM and what the associated clinical implications are. Bole et al recently published their findings of 273 consecutive primary IPP surgeries to address this question.³

In this retrospective review, 20.1% of patients were found to have idiopathic corporal asymmetry. No preoperative factors, including PD, were predictive of ACM. In fact, of the 197 patients without PD, 17.3% of them had corporal asymmetry. The surgeons in this cohort routinely placed true measured cylinder size regardless of asymmetry unless adjunctive straightening procedures were performed. The amount of residual curvature was not different between those that had an asymmetric vs symmetric device placed. Of the patients with ACM, 43 (78.2%) had asymmetric cylinders placed that were true to measured size. Of these, 12% underwent additional straightening procedures. Upon final inflation at the conclusion of the case, 16 of the 43 (37.2%) had a mild residual curvature (median curvature 10 degrees) but were considered functionally straight, defined as less than 20 degrees based upon the 2016 expert consensus.⁴ Of the patients who had symmetric cylinders placed despite ACM, 33.3% underwent additional straightening procedures, leaving 50% with residual curvature at the conclusion of the case (median curvature 12.5 degrees). Patients with ACM were significantly more likely to have mild residual curvature than patients with symmetric corporal measurements (P < .0001).³

The authors included their surgical algorithm for managing penile curvature at the time of IPP surgery (Figure 1). Maneuvers include penile modeling, plication, and incision or excision with grafting, with the goal being a functionally straight penis. An important intraoperative consideration is device selection. Currently, Coloplast (Humlebaek, Germany) and Boston Scientific (Marlborough, Massachusetts) are the only companies that have an IPP approved for use in the United States. Use of the Boston Scientific CX700 or Coloplast Titan will help achieve additional penile straightening with regular cycling and use of the device.⁵ Due to its expansion in both length and girth, the Boston Scientific LGX700 device may exacerbate penile deformities and is not recommended for use in men with PD.⁶ Postoperatively, all patients with penile curvature should be encouraged to cycle their device daily, leaving it inflated for at least 20 minutes.

This paper highlights several important discussion points. First, a preoperative history is the first line of defense to identify patients at risk for PD. Patients with ED are at greater risk for PD, however, they may not be able to identify the presence of curvature depending on the severity of their ED.⁷ In this cohort, the incidence of occult curvature was 27.8%. Patients who respond poorly to intracavernosal injections may not demonstrate curvature with an in-office injection or may grossly underestimate their curvature based on the rigidity of their erection. Second, management of intraoperative ACM is a point of debate among prosthetic surgeons. Some would argue true to size cylinder placement regardless of symmetry, while others would advocate placement of a symmetric device if the measurements are within 1 cm. Critics of placement of a symmetric device would argue that placing a longer cylinder than the corporal space allows increases the risk of postoperative curvature, while an undersized cylinder may result in supersonic transporter deformity. The last take-home point from this paper is that while the steps of IPP surgery are well defined, there are subtle nuances in technique. Failure to recognize an intraoperative complication, improper dilation, inaccurate corporal measurements, incorrect cylinder size placement, or unique anatomic differences may result in a poor cosmetic or functional outcome leading to patient dissatisfaction, need for revision surgery, and additional complications (Figure 2). If not recognized intraoperatively, many of these findings will become more pronounced over time with device use.

In Figure 2, we have included pre- and postoperative photos from a revision case of a patient who reported 10-degree right curvature prior to IPP placement with AMS LGX700 21-cm cylinders with 2-cm right rear-tip extender (RTE) and 1-cm left RTE at an outside facility 1 year prior. At the time of revision surgery, the patient was noted to have 75-degree right curvature (Figure 2, A) and 15-degree dorsal curvature (Figure 2, B). At the time of revision surgery, a fluid leak was noted from the right cylinder. The device was replaced with Coloplast Titan 20-cm cylinders with 2-cm right RTE and 1-cm left RTE. After removal and replacement with the Coloplast Titan device, the patient was noted to have no dorsal curvature (Figure 2, C) and 5-degree right curvature (Figure 2, D).

Given the prevalence of ACM and PD in patients undergoing IPP placement, we would advise prosthetic surgeons include a discussion of penile curvature, intraoperative management of significant curvature, and what is considered functionally straight. Setting appropriate expectations with patients is not just a legal responsibility to obtain informed consent, but it is critical for patient satisfaction. Understanding the nuances of prosthetic surgery facilitates appropriate and efficient management of unanticipated intraoperative challenges.