Monthly Archives: May 2014

Erectile dysfunction Australia: History Mechanism of Action

John King, a nineteenth century physician, is credited with conceptualizing a “small, exhausting pump” applying negative pressure to the penis for the treatment of ED. He advocated that a “glass exhauster should be applied to the part, once a day”. Unfortunately, his device failed to maintain the erection once the glass exhauster was taken off the penis. It was not until 1917 when Otto Lederer patented the first VCD that used a compression ring to maintain the erection. However, it failed to win over medical peers’ approval. In 1974, an American entrepreneur, Geddings Osbon, invented and developed the first commercially available device, which became FDA approved in 1982. Though it was reported that Osbon used this device on himself for more than 20 years without failure, the device was initially met with skepticism among the medical community. Instrumental to its wide-spread popularity was Hadig, who published one of the earliest studies supporting its efficacy and safety profile. As more evidence emerged, acceptance by the urologic community culminated in the device being recommended by the American Urological Association as one of three treatment alternatives for organic ED.

More than 90% of men experience a functional erection with the VCD. Several companies have developed and marketed both hand-operated and battery-operated VCDs. These include Timm Medical Technologies (Eden Prairie, MN), Mission Pharmacal (San Antonio, TX), Encore (Louisville, KY), Mentor (Santa Barbara, CA), and Post-T-Vac (Dodge City, KS).

Even though these devices have been commercially available since the 1980s, the mechanics remain the same. They comprise three components: vacuum cylinder, battery or manually operated vacuum pump, and constriction rings of varying sizes. Usage involves placing the correct constriction ring on the open end of the cylinder, then applying copious amount of lubricant to the penis to create a seal once the vacuum cylinder is placed over. The manual or battery operated pump is activated to create negative pressure inside the cylinder, effectively drawing blood into the penis to create an artificial erection. Once the desired state is achieved, the constriction ring is moved onto the base of the penis to maintain the erect state; trial and error is used to determine the ring size that is most comfortable and effective. The cylinder is then removed and the patient is ready for sexual intercourse. To avoid ischemic injury to the cavernosal tissue, buy viagra online Australia the constriction ring should not be left on for more than 30 min.

Unlike the normal physiology of penile erection in which a complex interplay between neural inputs, vascular patency, and hormonal secretion is required, tumescence from VCD results from passive flow of mixed venous and arterial blood. Broderick et al. demonstrated by color Doppler ultrasound that the negative pressure transiently draws arterial blood into the sinusoidal spaces of the cavernosal tissues, increasing its diameter nearly twofold. The change in diameter owes itself to both intracorporal and extracorporal distention. The constriction ring placed at the base of the penis prevents the venous outflow. Color Doppler ultrasound performed after the placement of constriction ring, however, revealed no arterial inflow into the penis. This led to the recommendation that the constriction ring should not be left on for >30 min to prevent ischemic injury to the penis.

A recent review of literature revealed more than 63 reported cases of penile strangulation or incarceration from circular constriction objects placed on the penis. These objects ranged from metal rings to plastic bottles, condom rings, rubber bands, threads, and even hair.

The rationale behind using these improvised constriction rings was almost universally for erotic or autoerotic purposes; in some cases, however, patients were afflicted with mental illnesses. The degree of penile injury not only correlated to the type of objects used but more importantly, to the duration of ischemia. Nonmetallic objects had a tendency to cause more injury, possibly due to their elasticity. Silberstein et al. reported that patients who presented after 72 h were more likely to sustain high-grade penile injuries. These patients were considered urologic emergencies and immediate intervention was warranted. In most cases, conservative management after the removal of constriction device was adequate. Nevertheless, in some instances, the evaluation of urethra either cystoscopically or radiographically was warranted to rule out urethral injury. In rare cases, surgical debridement or partial penectomy was indicated.

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