UDS will often demonstrate detrusor acontractility and urethral sphincter denervation or overactive bladder (OAB) with DSD.8 Anorectal malformations may have genitourinary and spinal abnormalities, including tethered cord or iatrogenic injury, but may also have NBD without obvious etiology. These children may exhibit OAB

with or without DSD (upper motor neuron lesion) or detrusor acontractility with sphincter denervation (lower motor neuron lesion).9 Posterior urethral valves (80%) often have bladder dysfunction with detrusor overactivity and diminished bladder compliance.10,11 Myogenic failure may be due to infrequent bladder emptying Inhibitors,research,lifescience,medical in conjunction with increased urinary output and is more often seen in the older age group. Uroflowmetry is noninvasive and can be used in patients

who void spontaneously. The flow pattern is accurate as long as the volume Inhibitors,research,lifescience,medical is > 50% of maximum voided volume.12 The shape of the flow curve denotes the detrusor function, outlet resistance, or external sphincter dysfunction Inhibitors,research,lifescience,medical during micturition.13 Voiding patterns include a bell-shaped (normal), tower (OAB), plateau (outlet obstruction), staccato (sphincter activity during voiding), and interrupted curve (acontractile or underactive bladder).2 Perineal patch electromyography (EMG) can be used as an adjunct in determining the etiology of an abnormal flow pattern or postvoid residual urine.14 Postvoid residuals (PVRs) using bladder scanning Inhibitors,research,lifescience,medical should show residuals of ≤ 20 cc or abnormal emptying is suspected in children. PVR is useful in patients on anticholinergic therapy. Invasive UDS is performed in the sitting or supine positions. Rectal and urethral catheters provide intraabdominal and intravesical pressures, respectively. Inhibitors,research,lifescience,medical The difference in these pressures is the detrusor pressure. A PVR is obtained in a non-CIC patient and patch EMG electrodes are positioned perineally in boys or paraurethrally in girls.15 EMG provides information on individual motor units at rest in response to sacral reflexes and during bladder filling and emptying with suspected or previously diagnosed NBD.9 During

bladder filling, saline infusion at a temperature of 21°; to 37°;C is Non-specific serine/threonine protein kinase performed at a rate of 5% to 10% of the expected bladder capacity/minute.16,17 Bladder capacity for children is determined from the Hjälmås equation: expected bladder capacity (mL) 5 × 1 (age in years × 30).16 For children with MM, the this website formula 24.5 × age (years) + 62 should be used.18 Children on CIC use the largest catheterized volume during the day over several days. At least two cycles of filling are required unless the child has no sensation and an NBD. The bladder has been sufficiently filled when the child has a strong urge to urinate, is uncomfortable, voiding starts, bladder pressures are > 40 cm of water, or the volume infused is > 150% of the expected capacity.