A careful history taken from the patient should note any previous abdominal or pelvic surgery, irradiation, or systemic disease. A history of intestinal resection or irradiation, renal failure, diverticulitis, regional enteritis, or ulcerative colitis would be especially important to consider when selecting a method of urinary diversion or bladder substitution. A complete blood count and measurement of serum electrolytes, urea nitrogen, and creatinine should be performed. The upper urinary tract should be imaged with intravenous urography, ultrasound, or computed tomography to determine whether hydronephrosis, renal parenchymal scarring, or calculous disease exists. Contrast imaging of the small or large bowel or colonoscopy should be considered preoperatively for patients with a history of significant intestinal irradiation, occult bleeding, or other gastrointestinal diseases. Patients with benign bladder diseases—such as a reduced bladder capacity due to neurologic disorders or irradiation, bladder fistulas, or interstitial cystitis—are occasionally considered candidates for urinary diversion or bladder substitution to manage urinary incontinence; however, with such patients, careful evaluation of bladder function and anatomy is required, as adequate urinary function can often be restored by urinary tract reconstruction, pharmacologic manipulation, or intermittent catheterization.