What are long-term mechanical failure rates for 2-piece versus 3-piece inflatable penile prostheses?
Executive summary
Published series and reviews report that contemporary 3‑piece inflatable penile prostheses (IPP) show device survival of roughly 87–96% at 1–5 years and about 77% at 10 years, with mechanical failure accounting for ~11% of removals in one 27‑year single‑center cohort (survival: 96.2% at 1 yr, 86.7% at 5 yr, 77.5% at 10 yr; mechanical failure 11.0%) [1]. Systematic reviews and multiple articles note that 2‑piece implants and malleable devices have comparable or in some analyses higher survival than 3‑piece IPPs, but cohort sizes for 2‑piece devices are smaller and the Ambicor 2‑piece now represents under 5% of implants, limiting direct long‑term comparisons [2] [3].
1. What the largest contemporary studies report on 3‑piece IPP survival
Large contemporary series and a 27‑year single‑center retrospective report show excellent mid‑term survival for 3‑piece devices: pooled/series survival estimates cited include ~96% at 1 year, >87% at 5 years in older contemporary reports, and 77.5% device survival at 10 years in the 27‑year cohort; mechanical failure comprised 11% of device removals in that cohort with cylinders, pumps and reservoirs all implicated [4] [1].
2. How 2‑piece (Ambicor) data differ and why comparisons are hard
The Ambicor 2‑piece was designed to eliminate a separate reservoir and has shown low early mechanical failure in early series (2.3% at mean 43 months in an early report), good satisfaction, and redesigns after earlier failure modes; however contemporary use is uncommon (<5% of implants), so long‑term, large‑cohort head‑to‑head data versus modern 3‑piece devices are limited [2] [5].
3. Reviews and systematic analyses: mixed signals on relative durability
Narrative reviews and a cited systematic review summarize that malleable and 2‑piece implants have in some analyses shown higher survival than 3‑piece IPPs; those syntheses, however, draw on heterogeneous studies spanning older device generations, differing endpoints (reoperation, mechanical failure, infection), and variable follow‑up, reducing certainty about direct contemporary mechanical failure rate comparisons [2] [3] [6].
4. Failure modes and why device type matters for the cause of failure
Contemporary analyses break down mechanical failures for 3‑piece devices across cylinders, pumps, reservoirs and connections, with cylinders and pumps commonly implicated; 2‑piece devices historically suffered specific proximal cylinder leaks and flex‑point aneurysms prior to redesigns. Thus the pattern of mechanical failure differs between device classes, which complicates simple rate comparisons [1] [2] [7].
5. Reoperation and revision: infection vs mechanical causes
Population‑level analyses find that reoperation rates for infectious and noninfectious failures may be equivalent between semirigid (malleable) and inflatable devices in some datasets, emphasizing that overall revision risk is multifactorial (patient comorbidity, surgical technique, device generation) rather than purely a function of 2‑ versus 3‑piece architecture [8].
6. Limitations in the evidence and implicit agendas in reporting
Available publications mix device vintages, manufacturers and coating/antibiotic technologies; industry‑sponsored device reporting and single‑center series can bias survival estimates upward. The low contemporary market share of Ambicor/2‑piece devices (<5%) means vendors and centers favoring 3‑piece IPPs produce more and larger datasets, which implicitly skews comparative visibility [2] [6].
7. Practical takeaway for clinicians and patients
If the priority is long‑term survival data from large cohorts, contemporary evidence is strongest for 3‑piece IPPs with well‑documented 5–10 year survival [1] [4]. If reservoir concerns exist (prior pelvic surgery/radiation), a 2‑piece Ambicor remains a reasonable option with favorable satisfaction in smaller series and lower need for reservoir placement, but long‑term comparative mechanical‑failure rates are less certain because of small sample sizes and device rarity [2] [5].
Limitations: available sources do not include a large, randomized head‑to‑head trial directly comparing modern 2‑piece versus modern 3‑piece mechanical failure rates; therefore definitive superiority statements are not supported by current reporting [3] [2].