Mechanical Methods: Vacuum Devices and Penile Rings
Vacuum device is a pump machine consists of a plastic cylinder with an aperture at one end that is placed over the penile shaft, the other end is a pump mechanism that is used to generate negative pressure within the cylinder to draw venous and arterial blood into the erectile tissue. The erection is maintained by placing a constricting ring around the base of the penis and can slow down the speed at which blood leaves the penis.The constriction ring should not remain on for more than 30 – 45 minutes.
Discussion
There are no RCT studies in this area, but level 4 pre-post studies noted that the vacuum constriction device (VCD) is an acceptable alternative for ED therapy in men with SCI who may not tolerate other methods and whose hand function can warrant its use (unless a partner applies it). Premature loss of rigidity, petechiae and penile skin edema, lack of spontaneity, uncomfortable erections and a ‘cold penis” were cited as unwanted side effects. For safe practice, it is recommended that the maximum vacuum pressure should not exceed 250 mmHg (to prevent petechiae and ecchymosis) and the penile ring placed at the base of the penis to trap blood does not remain on for more than 30-45 minutes. An alternative vacuum device (Synergist) is a vacuum device within a silicone sheath that remains on the penis that can be used for longer periods of time due to the absence of constricting bands and a much lower vacuum pressure (8-20 mmHg), and which most patients found satisfying. Denil et al. (1996) reported on 20 couples where 93% of men with SCI and 83% of their female partners reported sufficient penile rigidity for intercourse obtained by the use of a vacuum device after 3 months, but by 6 months less than half the couples were satisfied with the device. Most side effects were temporary and minor. In the Moemen et al. (2008) study, while vacuum device therapy was the least favored option as opposed to ICI or PDE5i, 70% had a normal IIEF-EF score with its use. The authors suggested that the range in variation in patient response to this option might be related to acceptability of the vacuum device by the patient or his partner.
Conclusion
There is level 4 evidence (Moemen et al. 2008; Denil et al. 1996; Chancellor et al. 1994; Heller et al. 1992; Zasler and Katz 1989) that supports the use of medically sanctioned vacuum constriction devices and penile rings as treatment for erectile dysfunction in men with SCI.
