Device Placement Over Flaccid Tissue
A cylinder seals over the flaccid penis against the pubic bone.
- 3.8 cm: Cylinder diameter options (Sized to individual anatomy)
- Required: Water-based lubricant (Creates airtight seal)
- Class II: Device classification (FDA-regulated device)
- 1982: First approved (Osbon ErecAid device)
Cylinder selection and fit
Clinician picks cylinder length and diameter for comfort.
Sealing against the body
Lubricant forms an airtight seal at the base.
Positioning before vacuum draw
Correct placement prevents pinching and uneven pressure.
Manual Or Battery Pump Creates Negative Pressure
Pumping air out of the cylinder lowers internal pressure sharply.
- -100 to -225: Typical vacuum range (mmHg inside cylinder)
- 30-90 sec: Pump strokes to erection (Manual pump average)
- Built-in: Pressure release valve (Prevents overpressure injury)
- Manual & battery: Pump types (Two common designs)
Air evacuation from cylinder
Each pump stroke removes air, dropping chamber pressure.
Pressure gradient forms
Lower pressure inside pulls tissue outward toward the tube.
Built-in safety limiter
A release valve caps vacuum to avoid tissue damage.
Negative Pressure Pulls Arterial Blood Inward
Vacuum draws arterial blood into the corpora cavernosa.
- 2: Corpora cavernosa (Paired erectile chambers)
- 3-5 min: Time to engorgement (Typical draw duration)
- Arterial inflow: Blood source (Not venous pooling)
- Girth & length: Tissue expansion (Both increase under vacuum)
Arterial inflow response
Negative pressure draws arterial blood past resting volume.
Corpora cavernosa filling
Spongy erectile tissue expands as blood pools inside.
Passive mechanical process
No nerve signal needed — vacuum alone drives filling.
Mechanical Erection Without Nerve Signaling
Engorged tissue produces a rigid, functional erection mechanically.
- Up to 100%: Rigidity achieved (Device-dependent maximum)
- ~90%: Success rate (Across most causes)
- Nerve damage: Works independent of (Effective post-prostatectomy)
- Slightly cooler: Tip temperature (Blood pooled, not fresh flow)
Rigidity from blood volume
Trapped arterial blood stiffens tissue mechanically, not chemically.
Works regardless of cause
Effective even after nerve-sparing surgery or diabetes damage.
Rigidity gradient along shaft
Firmest near the base, softer toward the tip.
Constriction Ring Traps Blood, Cylinder Removed
A ring at the base holds blood in after cylinder removal.
- 30 min: Max safe ring time (Manufacturer safety limit)
- Silicone / rubber: Ring materials (Elastic constriction band)
- Ischemia: Risk after limit (Tissue oxygen deprivation)
- Anytime: Ring removal (Patient controls duration)
Ring placement mechanics
Ring slides off the cylinder onto the base before removal.
Cylinder withdrawal
Vacuum cylinder lifts away; ring alone maintains rigidity.
Time-limited safety window
Ring must come off within thirty minutes to protect tissue.