What were the typical protocols (device type, hours per day, duration) used in RCTs of penile traction therapy?
Executive summary
Randomized controlled trials of penile traction therapy (PTT) have used a wide range of devices and protocols; older trials typically prescribed long daily wear times (commonly 3–8+ hours/day for months), while newer RCTs with second‑generation devices (RestoreX) achieved significant effects with 30–90 minutes/day over 3 months and with follow‑ups to 6 months [1] [2] [3]. Trial durations most commonly span 3–6 months in the randomized phase, often followed by open‑label extension or longer observational follow‑up [4] [3].
1. Device types: from first‑generation extenders to RestoreX and Penimaster PRO
Early RCTs and cohort studies evaluated “first‑generation” mechanical traction extenders that required simple static stretch and often used clamping systems; later trials introduced second‑generation devices with dynamic adjustment, better clamp mechanics and counterbending (RestoreX, Penimaster PRO), and many RCTs reported using RestoreX in their randomized phases [3] [2] [5]. Reviews and device trials explicitly contrast older devices (which generally required long daily wear) with RestoreX’s innovations that allow effective shorter sessions [2] [3].
2. Typical hours per day: a shift from multi‑hour regimens to short, targeted sessions
Systematic reviews and registry practice historically recommended 3–8+ hours per day (some postoperative protocols instructed 8–12 hours/day for several months) and studies that randomized wearing frequency examined 30‑minute sessions once, twice or three times daily (equating to 30–90 minutes/day) as well as the long wear regimens [6] [1]. The RestoreX RCT and subsequent reports found clinically significant gains with 30–90 minutes/day, prompting clinicians to adopt 30 minutes/day, 5+ days/week in some practices [2] [7] [3].
3. Duration of treatment in RCTs: 3‑ to 6‑month randomized phases, often with extensions
Most randomized phases last 3 months (common in Peyronie’s device RCTs) or 6 months (notably in some post‑prostatectomy trials); for example, a post‑prostatectomy single‑center RCT randomized men to two PTT protocols for 6 months followed by a 3‑month open label phase, while the RestoreX PD RCT reported randomized outcomes at 3 months with follow‑up phases out to 6 months and beyond [4] [8] [3]. Regulatory and design documents show investigators frequently analyze outcomes at the end of the randomized period (3 or 6 months) and then monitor durability during non‑randomized follow‑up [9] [3].
4. Compliance and tolerability: a major practical determinant reported in trials
Trials and reviews repeatedly note that compliance varies and influences protocol choice: early multi‑hour regimens produced lower adherence and higher dropout, whereas newer short‑duration RestoreX protocols reported higher completion rates and better tolerability in many cohorts; one review highlighted 87% completion in a PTT arm in a trial that used extended daily wear but noted adverse events in about 43% with only 6% stopping treatment [1] [3] [6]. Trial protocols therefore often build in pragmatic adherence expectations and subgroup analyses by total traction time (hours/day × days used) [9].
5. Heterogeneity in trial designs: why synthesis is difficult
RCTs differ by indication (Peyronie’s disease vs post‑prostatectomy penile shortening), device generation, prescribed daily wear (30 minutes to 12 hours), number of sessions per day, randomized phase length (3–6 months), and whether PTT is monotherapy or combined with injections (CCH) — all factors that limit direct comparison across trials [3] [2] [5]. Reviews call for standardized multicenter RCTs with blinded outcome recording and harmonized wearing‑time definitions to resolve these inconsistencies [6].
6. Competing interpretations and clinical practice implications
Proponents point to RestoreX RCT data showing mean gains (e.g., ~1.6 cm length, ~17° curvature improvement and IIEF benefit) with short daily sessions, arguing that device engineering has reduced necessary daily hours [3]. Skeptics and guideline reviewers emphasize that many earlier positive results used much longer wear times and that long‑term durability, optimal daily dose‑response and real‑world adherence remain incompletely standardized; major reviews and narrative articles call for larger multicenter RCTs and standardized protocols [5] [6].
Limitations of available reporting: trial protocols and reviews cited here report wearing ranges, randomized phase lengths and device types but do not present a single, universally accepted “typical” regimen; available sources do not mention a unified consensus protocol beyond the trends summarized above [3] [2] [6].