What is the evidence for penile traction therapy?
One of the earliest reports into the use of penile traction therapy (PTT) in patients with Peyronie’s disease (PD) was presented at the 4th Annual European Society for Sexual and Impotence Research (ESSIR) meeting in 2001 on a small study of eight men [Scroppo et al. 2001]. The inclusion criteria for the study involved all men with minimum 3 months of PD without concomitant ED and the men were instructed to use the traction device for at least 4 h a day for a total of 3–6 months. The authors reported an increase in the mean penile length of 4.1 mm (100.5 mm before and 104.6 mm after PTT) (p > 0.05) and decrease in mean erect penile curvature (EPC) of 14° (from 34° to 20°) (p < 0.05) in this small case series. The same group also presented their later findings on the use of PTT at the ESSIR meeting in the following year. Daily use of a penile traction device for 6 h a day in men with PD and severe penile retraction was associated with a longer stretched penile length (SPL) (average 0.8 cm gain) [Colpi et al. 2002a].
In the same meeting, the authors also reported the efficacy of PTT in ‘small penis’ treatment [Colpi et al. 2002b]. In a small series of nine men with ‘small penis’ and an initial mean SPL of 12 cm, PTT of at least 6 h per day for a minimum of 4 months resulted in the mean SPL gain of 1.8 cm (range 0–3.1cm). The majority of patients did not report significant adverse events despite the long duration of PTT. These findings were confirmed by another prospective study conducted in 23 men who complained of short penis [Nikoobakht et al. 2011]. Following PTT for 4–6 h per day during the first 2 weeks and then 9 h per day until the end of the third month with increasing traction forces during determined intervals, there was a statistically significant increased in penile length both for the flaccid (mean 8.8 ± 1.2 cm to 10.5 ± 1.2 cm) and for the stretched state (11.5 ± 1 cm to 13.2 ± 1.4 cm), after 3 months of use. Despite the significant increase in the circumference of the glans penis following PTT use, this study did not demonstrate any significant change in the proximal penile girth and the increase in distal penile girth was likely attributed to glans enhancement. In contrast, negligible changes in penile girth after 6 months of PTT were reported in a pilot prospective study in men with short penis [Gontero et al. 2008].
Moncada-Iribarren and colleagues presented the first noncontrolled randomized study on the use of PTT in men who underwent PD surgery [Moncada-Iribarren et al. 2007]. A total of 40 men who had PD surgery (12 men with graft and 28 men with penile plication only) were randomized to penile traction versus observation. The penile extender was instituted once the surgical incision had healed (approximately 2–3 weeks), for 8–12 h daily for a total treatment period of at least 4 months. For both groups, penile shortening after surgery ranged from 0.5 to 4.0 cm. The use of a penile extender device was associated with increased penile length ranging from 1 to 3 cm and appeared to be proportional to the number of hours per month that the patient was wearing the traction device. Furthermore, sustained treatment with PTD for 4 months provided an increase in penile length from 1 to 4 cm. The use of the device was well tolerated and only three patients had to decrease the number of hours of traction device use due to mild penile pain.
Levine conducted a pilot study of 11 men with longstanding PD (mean 29 months) who were trialled on PTT and instructed to wear the device for a minimum of 2 h per day, increased to a maximum of 8 h per day with the extender rods lengthened by 0.5 cm every 2 weeks for 6 months [Levine et al. 2008]. Of the 10 men who completed the study, there was a 33% measured improvement in EPC, ranging from 10° to 45°, and a reduction in mean EPC from 51° to 34°. The SPL increased by 0.5 cm to 2.0 cm. They reported for the first time that PTT increased the erect penile girth by 0.5 to 1.0 cm with an improvement in hinge effect in four out of four men with advanced narrowing or indentation. No patient reported significant adverse events such as changes to penile sensation, worsening erectile function or skin injury. Overall the patients reported high satisfaction rates and the (International Index of Erectile Function) IIEF scores increased by at least four points in 50% of subjects (from 18.3 to 23.6) after 6 months of PTT.
Another important study in the use of PTT for men with PD was published a year later. Gontero and colleagues reported the results of PTT use in 19 men with minimum of 12 months of PD and pre-existing curvature of less than 50° [Gontero et al. 2009]. In contrast to the study by Levine and colleagues [Levine et al. 2008], the penile measurements were determined by photography taken by the investigators after a pharmacologically induced erection in the office or at home. The patients were required to wear the device for a minimum of 5 h per day, up to a maximum of 9 h. For the 15 patients who completed the study, the penile curvature decreased from a mean of 31° to 27° and there was significant improvement in the mean flaccid and SPL measurements of 1.3 and 0.8 cm respectively. Importantly, the authors showed no further change in penile curvature or length in the following 6 months after the device was not used. In addition, there was no significant change to the IIEF score.
The role of PTT as part of a multimodal treatment strategy for men with PD was also explored by Abern and Levine in 2008 [Abern and Levine, 2008]. In a noncontrolled pilot study, there was a trend toward improvement with intralesional injections plus PTT compared with injections alone. The study was formally published in 2011 [Abern, 2012] and involved a 24-week study with the combined use of PTD in addition to intralesional verapamil and oral L-arginine and pentoxifylline in men with PD with symptoms for over a year. This is a patient self-driven PTT group and those electing to wear a traction device were advised to wear the device for 2–8 h daily, but for intervals no longer than 2 h, and to add progressive device traction every 2–3 weeks. A total of 54% of patients reported improvement in EPC in the PTT group compared with 46% of patients who did not use PTT. In patients who responded to PTT, the mean reduction in EPC was 26.9° versus 20.9° in men without PTT (p = 0.22). With regards to SPL, patients on PTT gained a mean of 0.3 cm (SD 0.9 cm; p = 0.06), while the men without PTT lost an average of 0.7 cm of length (SD 1.1 cm; p = 0.46). Subgroup analysis of men on PTT showed a trend toward SPL benefit, with 56% of men with PTT use greater than 3 h per day having measured SPL gain versus 43% of men using it up to 3 h per day (p = 0.18). Multivariate analysis confirmed that the duration of PTT use significantly predicts SPL gain (0.38 cm gain for every additional hour per day of PTT use, p = 0.007).
Most men with advanced ED sometimes also report shortening of penile length and require penile prosthesis implantation. The potential benefit of PTT to preserve and maintain penile length following the removal of penile prosthesis implantation was highly desired given that significant corporal fibrosis occurred following penile prosthesis explantation. Levine reported a noncontrolled pilot study in 10 men with drug refractory ED and a complaint of a shorter penis, who were subjected to PTT use to maintain the penile length before inflatable penile prosthesis implantation [Levine and Rybak, 2011]. At the end of the 4-month study period of 2–4 h daily use of PTT, 70% of men had measured erect length gain compared with baseline pretraction SPL up to 1.5 cm. No man had measured or perceived penile length loss after inflatable penile prosthesis implantation. However 60% of men complained of difficulty applying the device, with occasional pain that diminished with use in 40% of men.