Postoperative urinary retention

What it is

Urinary retention after surgery is an inability to urinate despite the sensation of needing to do so, appearing several days into an otherwise good recovery, for example after spinal surgery, with the last normal void some hours earlier and felt to be incomplete.

Overflow, which is urinary retention, is overdistention of the bladder caused by impaired detrusor contractility or bladder outlet obstruction, and it leads to urine leakage by overflow. It accounts for 5 percent of patients with chronic incontinence.

Acute urinary retention, acute on chronic urinary retention and chronic urinary retention are read as separate diagnoses.

Causes and risk

The causes are anticholinergic medications, benign prostatic hyperplasia, pelvic organ prolapse, diabetes mellitus, multiple sclerosis and spinal cord injuries.

Urinary retention, the overflow bladder, is itself caused by bladder outlet obstruction or denervation of the detrusor.

How it presents

Suprapubic pain with an inability to pass urine over a matter of hours, with no prior significant lower urinary tract symptoms, and insertion of a Foley catheter that drains a large volume of clear urine. Catheterization several days after spinal surgery in a man of 62 who became unable to urinate despite the sensation of needing to do so, whose last normal void was about 12 hours earlier and felt incomplete, produced 900 mL of clear-appearing urine. In a man of 72 with suprapubic pain and inability to pass urine for the past 12 hours, with no prior significant lower urinary tract symptoms, 1200 mL of clear urine drained on insertion of a Foley catheter and a serum creatinine of 130 nmol/L, the diagnosis is acute on chronic urinary retention, and not acute urinary retention, chronic urinary retention or anuria.

Where the retention is chronic rather than sudden, it shows as dribbling of urine, inability to empty the bladder, urinary hesitancy, and urine loss without a recognizable urge or sensation of fullness or pressure in the lower abdomen. It does not usually occur unless bladder emptying is poor, with postvoid residual volumes above 200 to 300 mL.