What are the comparative outcomes of penile traction devices versus collagenase injections for Peyronie’s disease?
Executive summary
Collagenase Clostridium histolyticum (CCH) injections are an evidence-based, FDA-recognized intralesional therapy that produce meaningful curvature reduction in randomized trials, while penile traction therapy (PTT) — particularly with modern devices — shows consistent but generally smaller improvements in curvature and gains in penile length as monotherapy [1] [2]. The clearest signal in the literature is that combining PTT with CCH modestly augments outcomes (curvature reduction and length preservation) and can reduce the number of CCH cycles needed, but trial heterogeneity, device differences, and conflicts of interest complicate precise comparisons [3] [2] [4] [5].
1. What each therapy is and how it works
CCH is an enzymatic intralesional injection that digests interstitial collagen in Peyronie’s plaque and was proven in large double-blind, randomized, placebo-controlled phase III studies to improve penile curvature and functional outcomes, forming the backbone of non‑surgical injectable therapy [1]. Penile traction therapy applies mechanical stretch (mechanotransduction) to the tunica and plaque over time with the goals of softening plaque, remodelling collagen, increasing stretched penile length, and reducing deformity; its theoretical basis is supported by tissue-culture and mechanobiology data and a history of traction use in other specialties [6] [7].
2. Head-to-head efficacy: CCH injections
Large meta-analyses and phase III trials report that intralesional CCH achieves clinically meaningful curvature improvement across diverse cohorts, with measurable gains in curvature and patient-reported functional scores that outperform placebo in controlled settings [1]. Real-world adherence matters: multicenter and single‑center series show variable compliance (around 70% in one 7‑year analysis) and that compliant patients generally had greater curvature reduction, highlighting that outcomes depend on completing the treatment protocol [8].
3. Head-to-head efficacy: penile traction therapy (PTT) monotherapy
Systematic reviews and contemporary device trials report that modern PTT devices can reduce curvature modestly (often in the 20–30% range) and recover length by approximately 1.5–2.3 cm on average in some series, with newer, shorter‑duration protocols improving adherence versus older 3–8 hour regimens [2] [9] [10]. Earlier literature was mixed, and historically many PTT studies showed limited or no effect when combined with intralesional therapy, although device variability and protocol differences undermined straightforward conclusions [3] [7].
4. Combination therapy: additive benefits and the size of the effect
Multiple contemporary analyses and trials indicate that adding PTT to CCH enhances outcomes beyond CCH alone, typically by a modest margin — reported as an additional ~5–10% curvature correction in several reviews and device-specific randomized data showing meaningful benefit with RestoreX when paired with CCH [2] [3]. Observational series and some centers report reduced numbers of CCH cycles and improved cost-efficiency when PTT is incorporated, with one clinical report asserting fewer cycles were required to reach similar results [4] [11].
5. Safety, adherence, and conflicts that shape interpretation
Both interventions are generally well tolerated; PTT adverse effects are most commonly local discomfort and transient glans numbness, while CCH carries risks inherent to intralesional injections and requires clinic visits [9] [8]. Trial and author conflicts deserve scrutiny: key device developers have disclosed financial ties (for example, Dr. Trost and RestoreX), and device heterogeneity — different extenders, wear times, and protocols — limits generalizability of pooled results [5] [10].
6. What the evidence supports for practice and remaining uncertainties
The strongest, highest-level evidence supports CCH as an effective non‑surgical therapy for appropriate patients, and PTT is a valuable adjunct that consistently improves length and modestly enhances curvature outcomes when used with CCH or as standalone therapy in selected cases [1] [2] [12]. However, differences in devices, adherence, protocols, and study designs mean that exact quantitative comparisons (how many degrees or cm more one approach yields over the other in every patient) remain imprecise; cost‑effectiveness analyses and longer‑term randomized data comparing standardized modern PTT devices versus CCH monotherapy are still needed to settle practice patterns [1] [9].