From the Guidelines
Postoperative urinary retention is commonly caused by a combination of factors including anesthesia, pain medications, surgical manipulation, anticholinergic medications, excessive IV fluids, immobility, anxiety, and pre-existing conditions such as benign prostatic hyperplasia or neurological disorders. According to the most recent and highest quality study available, which is from 2012 1, major risk factors for urinary retention include male sex, pre-existing prostatism, open surgery, neoadjuvant therapy, large pelvic tumours, and APR.
Causes of Postoperative Urinary Retention
- Anesthesia and pain medications like opioids can suppress the neural pathways controlling urination by inhibiting bladder muscle contraction and increasing urethral sphincter tone
- Surgical manipulation near the bladder or prostate can cause local inflammation and edema, temporarily disrupting normal urinary function
- Anticholinergic medications (such as atropine, scopolamine, and some antihistamines) decrease bladder contractility and increase outlet resistance
- Excessive IV fluids during surgery can overdistend the bladder, weakening its ability to contract effectively
- Immobility after surgery makes it difficult for patients to assume normal voiding positions, while anxiety and unfamiliar surroundings can inhibit the relaxation needed for urination
- Pre-existing conditions like benign prostatic hyperplasia or neurological disorders increase the risk
Management of Postoperative Urinary Retention
- Intermittent catheterization
- Pharmacological interventions (alpha-blockers like tamsulosin 0.4mg daily for men, bethanechol 10-50mg three times daily to enhance bladder contractility)
- Reducing opioid use
- Early mobilization
- Privacy during voiding attempts
- Ensuring adequate hydration while avoiding bladder overdistention
As noted in another study from 2012 1, a brief duration of transurethral drainage is desirable because increasing duration is associated with increasing risk of urinary tract infection (UTI). The transurethral bladder catheter may be safely removed on postoperative day 1, even if epidural analgesia is used, to reduce the risk of UTI and promote early recovery. Most cases of postoperative urinary retention resolve within 24-72 hours as the effects of anesthesia wear off and normal mobility returns.
From the Research
Causes of Postoperative Urinary Retention
The causes of postoperative urinary retention can be attributed to various factors, including:
- Patient-related factors such as age, benign prostatic hyperplasia, and lower urinary tract symptoms 2
- Surgery-related factors including operative time, intravenous fluid administration, type of anesthesia, and procedure type 2
- Anesthetic and analgesic modalities, particularly spinal anesthesia with long-acting local anesthetics and epidural analgesia 3, 4, 5
- Postoperative opioid pain management 4
- Pre-existing bladder dysfunction 4
Risk Factors
Specific risk factors for postoperative urinary retention include:
- Spinal anesthesia, which is a main independent modifiable risk factor for urinary catheterization 5
- Maximum bladder capacity < 500 mL 5
- Duration of surgery ≥ 60 min 5
- First scanned bladder volume at the Post Anesthesia Care Unit ≥250mL 5
- Age ≥ 60 years 5
- Epidural analgesia, which can result in significantly longer periods of catheterization 4
- Number of pain medications, which is more predictive of postoperative urinary retention than the mode of analgesia delivery 4
Procedure-Related Factors
Certain procedures are associated with a higher risk of postoperative urinary retention, including: