The urodynamic evaluation of lower urinary tract symptoms in men

Urodynamic investigation is recommended when it influences the management of patients and is used before invasive therapies for lower urinary tract dysfunction. Urodynamics has been shown to improve symptomatic and objective outcomes after surgical treatment of bladder outlet obstruction (BOO) of which benign prostatic obstruction (BPO) is the principal cause. The diagnosis of BOO is made from pressure-flow studies (PFS) of micturition using the International Continence Society nomogram, which places patients in three categories: obstructed (BOO index [BOOI] ≥ 40); equivocal (no definite obstruction; BOOI 20–40); and no obstruction (BOOI ≤ 20). PFS are reliable and reproducible; however, they are invasive tests, and efforts to find sensitive and specific methods of diagnosing BPO without catheterization are under way. Promising noninvasive techniques include the penile compression release index, the condom catheter method, and the penile cuff technique. Uroflowmetry and the ultrasound estimation of residual urine remain useful screening tests. Due to its diagnostic and prognostic value, urodynamics is recommended to assess lower urinary tract symptoms before surgery to relieve BOO.