Rigi10™ Malleable Penile Prosthesis
Also Known As
Cystometric capacity, Functional bladder capacity, Maximum anatomic bladder capacity (MABC), Maximum cystometric capacity, Vesical capacity
Definition
Bladder capacity refers to the volume of urine that the bladder can hold before triggering the sensation of fullness and the need to void.1 It is a critical urodynamic parameter used in the evaluation and diagnosis of various urological disorders.2 In healthy adults, normal functional bladder capacity typically ranges from approximately 300 to 600 milliliters.1,3 This capacity represents the physiological volume at which an individual experiences a strong desire to void, though the maximum anatomical capacity may be somewhat larger.4
The bladder’s ability to accommodate increasing volumes of urine without a significant rise in intravesical pressure is known as compliance.5 In a normal bladder with capacity of 400 to 500 mL, a rise in detrusor pressure of 15 cm H₂O or less is considered normal.6 This accommodation is facilitated by the bladder’s unique composition of collagen, elastin, and smooth muscle, which provide both elasticity and distensibility.7
Bladder capacity varies significantly with age, with infants and children having considerably smaller capacities than adults.8 Various formulas have been developed to estimate expected bladder capacity in children of different ages, though these may not always accurately predict actual measured volumes, particularly in infants under one year of age.9
Clinical Context
Bladder capacity serves as a crucial diagnostic parameter in the evaluation of numerous urological conditions.2 Accurate assessment of bladder capacity is essential for reliable urodynamic testing and for identifying potential underlying pathologies.2,4 Abnormal bladder capacity, whether increased or decreased, may indicate various urological disorders requiring medical attention.
A reduced bladder capacity (less than 300 mL in adults) often manifests as increased urinary frequency, urgency, and nocturia.1,3 The most common causes of pathologically reduced bladder capacity include urinary tract infections, involuntary detrusor contractions, and low bladder compliance.6 Other conditions associated with decreased capacity include interstitial cystitis, bladder cancer, radiation cystitis, and certain neurological disorders affecting bladder function.5,7
Conversely, an abnormally large bladder capacity may be associated with detrusor underactivity, bladder outlet obstruction, or certain neurological conditions affecting bladder sensation.4,8 Patients with significantly increased bladder capacity may experience infrequent voiding, difficulty initiating urination, and incomplete bladder emptying, potentially leading to urinary retention and recurrent urinary tract infections.7
Bladder capacity is typically measured during urodynamic testing, which involves filling the bladder at a controlled rate while monitoring intravesical pressure.2,9 This assessment provides valuable information about bladder function, including capacity, compliance, and the presence of involuntary detrusor contractions.4,6 The results of these tests guide clinical decision-making regarding diagnosis, treatment planning, and evaluation of treatment efficacy for various lower urinary tract disorders.3,5
In pediatric urology, bladder capacity assessment is particularly important for evaluating conditions such as nocturnal enuresis, daytime incontinence, and recurrent urinary tract infections.8,9 Age-appropriate reference ranges are essential for accurate interpretation of findings, as bladder capacity increases significantly throughout childhood development.8