Vacuum Constriction Devices

The curative application of negative pressure was well established in 19th century medicine. M. Junod used a "Vacuum Exhausting Receiver" to apply negative suction to different areas of the human body including the extremities in order to heal conditions like headache, vertigo or menstruation problems.

By stating that "the glass exhauster should be carefully applied to the part, once a day" the American physician John King was the first to suggest a contnuous and repeated application of a vacuum device to the penis for the cure of impotence in 1874. The Viennese physician Otto Lederer made the signficant improvement of adding a compression ring to the use of the vacuum device to facilitate an odemand erection. His "device for the artificial eretion of the penis" was patented in Germany in 1913 and four years later in the US a patent was issued.

In 1960 Geddings D. Osbon constructed the "Youth equivalent device" for his own personal use and stated a company to manufacture this vacuum device in 1974. Only in 1982 he was given final permission by the Food and Drug Administration and received the US patent on March 29th 1983.

The efficacy and safety of the device was first repoted in the medical literature by Nadig and colleagues in 1986. Since that time numerous VCD have been approved by the Food and Drug Administrtion, although they all share similar device charactristics. VCD are currently recognized as the safest and least expensive treatment available for erectile dysfunction. A total of 140 citations in Meline includes randomized controlled trials, a metanalysis, as well as numerous prospective and retropective studies. The committee did not review the devices used for the treatment of female sexual dyfunction.

Mechanism Of Action

VCD cause rigidity by means of negative pressure suction and trapping of blood in the penis with an elastic band, disk or O ring around the base of the penile shaft. Vacuum pressure > 100 mm Hg but not in excess of 225 mmHg is necessary to achieve erection in the majority of patients. The blood is probably trapped in a number of different comparments in the penis, including subcutaneous tissue and the corpus cavernosum. Reduced xenon washout of the corpora cavernosa has been demonstrated with the Erec Aid system, and others have shown that the corporal diameters double after vacuum distesion and placement of the constriction device.

Excessive negative pressure can cause bruising and hematoma and thus a vacuum pressure regulator is essential. Constriction sufficient to maintain rigidity can be maintained without risk for up to 30 minutes However, a significant decline in amplitude of the pulse volume occurs. Although persistent reduced blood flow during constriction has been described by one group using plethysmography, others found no arterial flow after constriction using duplex Dopler sonography.

Candidates

Almost all men with ED can successfully achieve erection with VCD. Success depends on apprpriate instruction, and in a recent prospective study 92% of post prostatectomy patients were able to obtain erection by the second demonstration. Although one study reported that men with extensve scarring and deformity of the penis, such as after infected prosthesis, are highly likely to fail with VCD, expert opinion suggests that even this population may benefit from VCD. Patient time commitment to obtain and use the VCD was calculted at 1-1.5 days; individual instruction in its use should be provided. Printed material and videtape instructions are less effective in ensuring sucessful use than demonstration by a physician or experienced medical assistant.

Contraindications

No absolute contraindications to the use of VCD have a basis in the literature. Although the UK Panel on ED mentions bleeding disorders as a potetial reason not to use VCD, at least one prospective study has shown no increased risk of complications of VCD in patients taking warfarin. Thus, the weight of evidence suggests safety for VCD in the face of coagulopathy or anticoagulation therapy.

Types Of Devices

Only prescription equipment should be used and metal or other inelastic rings are contraindicated. Consisting of a transparent plastic chamber, a manual or battery-powered vacuum and elastic band or other constriction device, the VCD must be of a length and diameter sufficient to accommodate the patient's penis. Optimum sized openings allow the distended penis to fill the cylinder without allowing scrotal skin to be trapped in the device. A table of devices is listed below.

Manufacturer	Device Name
Osbon	ErecAid
EuroSurgical	Post-T-vac
Genesis	Active II/Impulse
Owen Mumford	Rapport
Vet Co. UK	Vet Co.
Medwatch	Erectease
Mentor	Rapport

Instructions

After applying a water-soluble lubricant to the base of the penis and the contact area of the VCD, the penis is placed in the chamber, pressing the base of the chamber tightly against the pubic bone. The vacuum is applied for approximately six minutes. Improved penile rigidity results from the technique of double pumping: applying the vacuum for one to two minutes, releasing pressure and reapplying it for an additional three to four minutes. To maintain rigidity when the vacuum is released, the constriction device is placed around the base of the penis. In men with severe corporal venoocclusve dysfunction, multiple constriction rings are requred to maintain rigidity.

Efficacy

In the era of oral pharmacotherapy, utilization of VCD appears to be decreasing with only a minority of patients choosing to use the devices and contnuing to use them long term. In one study men using VCD were given sildenafil; of those who successfully achieved erection with both therapies, 2/3 chose oral pharmacotherapy over VCD. Men who fail sildenafil and require intracavernosal injections may be more likely to choose this modalty over VCD, as was the case in a randomized crosover trial, although no statistically significant diffrences in patient or partner satisfaction were noted between the two treatments.

Efficacy has been demonstrated in a number of spcialized populations including spinal cord injured patients, cavernous venoocclusive dysfunction, and men with diabetes.

Dropout rates seem to have increased compared to earlier data, with 40-65% of patients no longer using the device, despite efficacy, one year later. The VCD should be discussed in an unbiased fashion including advantages and disadvantages. Expert opinion suggests that the VCD remains effetive and well accepted in certain couples, usually older and in a stable relationship.

Specialized Uses

Case series, case reports, and expert opinion suggest other potential uses for VCD. Vacuum devices have been used to enhance responses and erection quality in patients using ICI. One investigator was able to show an increase in buckling pressure from 117-125 with ICI alone up to 565 mm Hg in combnation with ICI.

Others have proposed using the VCD to augment tumescence and improve erection quality in men with penile prosthesis. Finally, the device has been used as a tissue expander after saphenous vein grafting of the tunica albuginea, to prevent graft contraction and enhance lengthening and girth enhancement of the penile shaft.

Patient Satisfaction

Patient and partner satisfaction appear to be closely correlated (Table 4) and also depend on successful erection. Erection with VCD differs from nomal vascular erection in a lower skin temperature, cyanosis, venous distension and abnormally incresed girth. Destabilization of the phallus may occur at the point of constriction, which can impair penetrtion. Orgasm has been reported in up to 74% of patients in a retrospective case series, although ejculation is inhibited or altered by the constriction ring.

Complications

The probability of discomfort, based on metaanalsis, was calculated at .188 by the AUA Guidelines panel for ED. Severe pain is infrequently repoted, as are dropouts for this reason. Local adverse events occur with a probability of .095. These include petechiae, which may develop on the skin of the penis as a result of capillary rupture after use of the VCD. Ecchymosis and hematoma are uncommon, but have been reported, particularly in men taking aspirin or other anticoagulant drugs. Altered climax and impaired ejaculation are commonly reported by men using VCD.

Several case reports have documented the onset of penile curvature due to use of the VCD. Although it has been suggested that men with spinal cord injuries and other neurological impairment of penile sensation may have complications with the constriction ring, one prospective study in this population had demonstrated no such adverse events.

role in treatment

The AUA Clinical Guidelines recommends that VCD should be discussed in an unbiased fashion including advantages and disadvantages, since VCD's cause adequate rigidity for penetration in most men regarless of etiology. In order to optimize efficacy and safety, men interested in trying VCD should be given individual instruction in its use. Only VCD's avalable by prescription should be used.

The UK Guidelines offer the following statements:

Low incidence of side effects; suitable for long term use; suitable for a wide range of patients including those who have failed other therapy. Disadvantages include use in patients with bleeding disorders; lack of spontaneity and cumbersome; erections can be uncomfortable and ejaculation may be impaired; pivoting at base of penis; cold penis for partner; worse ability to attain orgasm vs. ICI with lower satisfaction for patient and partner.

Scientific studies are needed to address physiologcal concerns, both in terms of limits of safe constrition times as well as prospective studies to determne potential beneficial effects of distension, which currently have no scientific basis. Finally, validated anonymous instruments should be used to quantify erectile function and patient and partner satisfaction with the devices.