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214 Challenging Concepts in Urological Surgery
150
Strong
pdetQmax
(cm H2O)
normal activity
weak
obstructed
equivocal
unobstructed
100
40
20
0
02
0
Qmax (mL/s)
30
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Evidence base UPSTREAM
study
Symptom outcomes are non­inferior when invasive urodynamics is included in the assessment of male LUTS but further analysis is needed to determine the group of patients for whom urodynamics is useful. The UPSTREAM study did, however, show that patients reported satisfaction with understanding their underlying condition if urodynamics were performed prior to surgery.
12
Figure 21.2 The UDS reveals a mixed picture with proven detrusor overactivity but also evidence of
bladder outlet obstruction.
Learning point Urodynamics
BOO is a urodynamic diagnosis, which can only be measured through the concomitant measurement of urinary flow and detrusor pressure. It represents a high- pressure, low- flow situation.
The International Continence Society nomogram categorizes patients as obstructed, unobstructed, or equivocal (Figure 21.3).
Figure 21.3 Composite obstruction (BOOI) and contractility (BCI) nomogram. Pdet, detrusor
pressure; PdetQmax, detrusor pressure at maximum flow rate; Qmax, maximum flow rate.
The Bladder Outflow Obstruction Index (BOOI) gives a single numeric value through the equation:
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PdetQmax – (2 × Qmax) = BOOI
where:
● >40 = obstructed
● 20– 40 = equivocal
● <20 = unobstructed.
The Bladder Contractility Index (BCI) can be calculated through the following equation:
BCI = PdetQmax + (5 × Qmax)
where:
● <100 = detrusor underactivity
● >100 = normal
● >150 = strong.
In view of the confirmed evidence of BOO, recent UR, and urinary tract infection, the patient was offered a TURP. Following a detailed consent process including the risk of 20– 25% of urgency incontinence, the patient was listed for surgery. At TURP a high bladder neck and middle lobe were noted. Postoperatively, the patient successfully passed a trial without catheter.
Three months later, the patient is reviewed in clinic. Flow tests showed an im­proved flow rate of 25 mL/ s and minimal post- void residual. Unfortunately, however, the patient continues to suffer with bothersome urgency and frequency with occa­sional episodes of urgency incontinence.
He is commenced on a second- line anticholinergic, with advice to trial mirabegron (beta- 3 agonist) if there was no significant improvement in symptoms over a 4- week period. Subsequent review 6 months postoperatively confirms satisfactory improve­ment in symptoms following the initiation of mirabegron.
215Case 21 Benign prostatic enlargement and acute urinary retention
Expert comment OAB symptoms post TURP
Previous research has shown that OAB occurs in 50– 75% of men with BPO. After prostatectomy, evidence shows that 62% of patients with OAB preoperatively will have a normal cystometry postoperatively. However, 19% continue to experience storage symptoms post prostatectomy, and the more elderly the patient, the less likely these symptoms are to resolve. It is therefore important to counsel patients appropriately preoperatively regarding the possibility of persistent OAB symptoms requiring treatment following TURP. OAB symptoms resolve in 70% of men with BOO post TURP.13 Persistent storage symptoms appear to be more marked in men aged >80 years.
Learning point International Continence Society definitions
Urgency: complaint of sudden, compelling desire to pass urine, which is difficult to defer.
OAB: urinary urgency, usually with increased daytime frequency and nocturia, with or without urgency urinary incontinence, in the absence of any other pathology.
BPH: benign prostatic hypertrophy/ hyperplasia— enlargement of the prostate caused by prostatic cell hyperplasia/ hypertrophy (a histological diagnosis).
BPE: benign prostatic enlargement— enlargement of the prostate discovered on rectal examination.
BOO: bladder outflow obstruction. A diagnosis based on urodynamic investigations (pressure– flow studies ± imaging ± electromyography), generally (but not always) with relevant symptoms and signs, manifest by an abnormally slow urine flow rate, with evidence of abnormally high detrusor voiding pressures and abnormally slow urine flow during pressure– flow studies, with or without
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a high post- void residual. BOO can be functional (bladder neck obstruction, detrusor sphincter dysfunctions, or pelvic floor overactivity) or mechanical (prostatic enlargement, sphincter sclerosis, urethral stricture, meatal stenosis).
BPO: benign prostatic obstruction.
DO: detrusor overactivity. Urodynamic observation characterized by involuntary detrusor contractions during the filling phase that may be spontaneous or provoked.
DUA: detrusor underactivity. A diagnosis based on urodynamic investigations, generally (but not always) with relevant symptoms and signs, manifest by low detrusor pressure or short detrusor contraction in combination with a low urine flow rate resulting in prolonged bladder emptying and/ or a failure to achieve complete bladder emptying within a normal time span (a high post- void residual may be present).
Abnormal DRE
Suspicion of
neurological disease
High PSA
Abnormal urinalysis
Evaluate according to relevant guidelines or
clinical standard
Male LUTS
History (+ sexual function)
Symptom score questionnaire
Urinalysis
Physical examination
PSA (if diagnosis of PCa will change the
management – discuss with patient)
Measurement of PVR
Significant PVR
US of kidneys
+/– Renal function
assessment
Medical treatment
according to treatment
algorithm
Manage according to
EAU mLUTS
treatment algorithm
No
Bothersome
symptoms
Yes
FVC in cases of predominant
storage LUTS/nocturia
US assessment of prostate
Uroflowmetry
Benign conditions of
bladder and/or prostate
with baseline values
PLAN TREATMENT
Treat underlying
condition
(if any, otherwise
return to initial
assessment)
Figure 21.4 Assessment algorithm of LUTS in men aged 40 years or older. DRE, digital rectal
examination; FVC, frequency voiding chart; LUTS, lower urinary tract symptoms; PCa, prostate cancer; PSA, prostate specific antigen; PVR, post- void residual; US, ultrasound.
Adapted from EAU Guidelines on Management of Non- Neurogenic Male Lower Urinary Tract Symptoms (LUTS), incl. Benign Prostatic Obstruction (BPO) 2020.
Endoscopy (if test would alter the
choice of surgical modality)
Pressure flow studies (see text for
specific indications)
Surgical treatment according
to treatment algorithm
217Case 21 Benign prostatic enlargement and acute urinary retention
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no
no
Education + lifestyle
advice with or without
α1-blocker/PDE5I
Residual
storage
symptoms
(without indications for surgery)
Male LUTS
Bothersome
symptoms?
no
Prostate volume
>40 mL?
no
Storage symptoms
predominant?
yes
Long-term
treatment?
yes
no
yes
Nocturnal
polyuria
predominant
yes
yes
Watchful
waiting
with or without
education +
lifestyle advice
Figure 21.5 Treatment algorithm of male LUTS using medical and/ or conservative treatment options.
Treatment decisions depend on results assessed during initial evaluation. Note that patients’ preferences may result in different treatment decisions. PDE5i, phosphodiesterase 5 inhibitor.
Adapted from EAU Guidelines on Management of Non- Neurogenic Male Lower Urinary Tract Symptoms (LUTS), incl. Benign Prostatic Obstruction (BPO) 2020.
Expert comment Surgical options for male LUTS
Although LUTS medical management has improved the number of patients requiring surgical management, many of these medications have significant side effects.
Surgical management is now evolving at a pace with multiple new therapies being approved by the National Institute for Health and Care Excellence (NICE); these should be seen as possible interim treatments that may delay or prevent the need for a TURP or holmium laser enucleation of the prostate (HoLEP) procedure.
Add muscarinic
receptor
antagonist/beta
-3 agonist
Education +
lifestyle advice
with or without
5α-reductase inhibitor ± α1­blocker/PDE5I
Education +
lifestyle advice
with or without
muscarinic
receptor
antagonist/beta
-3 agonist
Education +
lifestyle advice
with or without
vasopressin
analogue
218 Challenging Concepts in Urological Surgery
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One such treatment is UroLift which, following results from the BPH- 6 study,14 has been approved by NICE for clinical use. The study confirmed improved preservation of ejaculatory function in comparison to TURP in addition to improved quality of recovery with acceptable improvement in symptoms but objective flow measurements which are less than TURP. Limitations, however, included small sample size and relatively stringent inclusion criteria, for example, prostate size <60 mL and no evidence of a median lobe. Revision rate is about 13% at 5 years.
Prostatic artery embolization is another technique increasing in popularity for the treatment of BPO. This interventional radiological technique involves direct injection of particles into prostatic arteries leading to devascularization of prostatic nodules. This is a technically challenging procedure shown to have good outcomes in the UK- ROPE study.16 The complication rate was low, and the procedure appeared clinically effective, producing a median 15- point IPSS score improvement 12 months post procedure. The procedure takes about 2– 3 hours under local anaesthesia. A preoperative CT arteriogram is usually required.
The Rezum system has also shown promise in relieving LUTS with preservation of ejaculatory function. The system employs thermal energy in the form of water vapour delivered to the prostate tissue via the transurethral route. Initial studies have shown acceptable improvement in IPSS scores with a recurrent treatment rate of 4.4% at 4 years. Again, this is limited to smaller prostate <80 mL in size.
A trial in the UK will hopefully be conducted comparing these minimally invasive therapies funded by the National Institute for Health Research.
The use of laser techniques in the management of BPO is increasing in prevalence with HoLEP being recommended by NICE guidelines in 2010.18 Greenlight laser has also been approved.19 An important trial in the consideration of laser prostatectomy is the UNBLOCS trial, a level 1 evidence randomized controlled trial inclusive of 410 men. The trial compared thulium laser vaporesection of the prostate (ThuVARP) to TURP, and confirmed similar outcomes in terms of IPSS but with TURP being superior in terms of improving Qmax. ThuVARP had a short learning curve, potentially increasing the appeal and reproducibility of this laser technique compared to others.
17
15
A final word from the expert
Male LUTS can be divided into storage, voiding, and post- micturition symptoms. These symptoms usually coexist and storage symptoms are usually the most bothersome and prevalent. It is important to assess these patients accurately, starting with a detailed history and focused clinical examination. Asking the question ‘Which is your most bothersome symptom?’ is often very helpful as treatment is directed at that symptom first. Once the history and examination are completed, baseline assessment is performed. This includes a 3- day bladder diary, a quality- of- life questionnaire, urine dipstick, free flow rate, and post- void residual. Other investigations such as cystoscopy, blood tests, and renal tract ultrasound scan are indicated if there are ‘red flag’ signs such as haematuria, increased residuals, abnormal rectal examination, and so on.
Conservative treatment is initially initiated in the form of bladder training, pelvic floor exercises, and fluid manipulation in the case of OAB; leg elevation, compression stockings, and exercise if there is nocturia with peripheral oedema; and double voiding if residual is slightly elevated.
After 6 weeks to 3 months, if these don’t help symptoms then medication is initiated. If there are OAB symptoms which are most bothersome then antimuscarinics can be tried. Usually, two different types are tried at maximum dose for a minimum of 4 weeks each. If these fail, then mirabegron is tried for a minimum of 6 weeks. Patients need to be warned about the risks of all these medications including cognitive impairment, dry mouth, blurred vision, and constipation with antimuscarinics and headaches and palpitations with mirabegron due to hypertension. If the voiding symptoms are bothersome then men can be tried on an alpha blocker with or
without a 5- alpha reductase inhibitor, remembering that the latter can take 3– 6 months to
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give maximum benefit. These can be given at the same time as antimuscarinics depending on symptom bother. Antimuscarinics are contraindicated in patients with a post- void residual of 150 mL due to the risk of causing retention.
If medical therapy fails, then urodynamics is indicated if it is going to change management and help in counselling the patient about potential options, thus giving the patient a more informed choice about their treatment.
Refractory OAB can be treated by onabotulinum toxin A into the bladder or sacral neuromodulation. Rarely, augmentation cystoplasty is performed. For the BOO due to prostatic enlargement, treatment can either be using minimally invasive techniques (Urolift, Rezum, prostatic artery embolization) or transurethral prostatectomy (monopolar TURP, bipolar TURP, HoLEP, Green light, ThuVARP). All options essentially have to be offered to patients and ultimately it is their choice to choose, with patients being referred to other centres if the operation they wish to have is not available locally. It has to be remembered, though, that the majority of these new treatments have no long- term data compared to TURP, which has been around for at least 30 years and has withstood the test of time!
219Case 21 Benign prostatic enlargement and acute urinary retention
References
1. Liao CH, Chung SD, Kuo HC. Diagnostic value of International Prostate Symptom Score voiding- to- storage subscore ratio in male lower urinary tract symptoms. Int J Clin Prac.t 2011;65(5):552– 558.
2. Rosier P, Schaefer W, Lose G, et al. International Continence Society good urodynamic practices and terms 2016: urodynamics, uroflowmetry, cystometry, and pressure- flow study. Neurourol Urodyn. 2017;36(5):1243– 1260.
3. Abrams P, Bruskewitz R, De La Rosette J, et al. The diagnosis of bladder outlet obstruc­tion: urodynamics. In: Cockett ATK, Khoury S, Aso Y, et al., editors. Proceedings, the 3rd International Consultation on BPH. World Health Organization 1995;299–367.
4. Chapple CR, Wyndaele JJ, Nordling J, et al. Tamsulosin, the first prostate- selective alpha 1A- adrenoceptorantagonist: a meta- analysis of two randomized, placebo- controlled, multicentre studies in patients with benign prostatic obstruction (symptomatic BPH). Eur Urol. 1996;29(2):155– 167.
5. Roehrborn CG, McConnell JD, Lieber M, et al. Serum prostate- specific antigen concentra­tion is a powerful predictor of acute urinary retention and need for surgery in men with clinical benign prostatic hyperplasia. PLESS Study Group. Urology. 1999;53(3):473– 480.
6. McConnell JD, et al. The long- term effect of doxazosin, finasteride, and combination therapy on the clinical progression of benign prostatic hyperplasia. N Engl J Med. 2003;349(25):2387– 2398.
7. Roehrborn CG, Siami P, Barkin J, et al. The effects of dutasteride, tamsulosin and combination therapy on lower urinary tract symptoms in men with benign prostatic hyperplasia and prostatic enlargement: 2- year results from the CombAT study. J Urol 2008;179(2):616– 621.
8. Speakman MJ, Kirby RS, Joyce A, Abrams P, Pocock R; British Association of Urological Surgeons. Guideline for the primary care management of male lower urinary tract symp­toms. BJU Int 2004;93(7):985– 990.
9. Hashim H, Abrams P. How should patients with an overactive bladder manipulate their fluid intake? BJU Int. 2008;102(1):62– 66.
10. Hashim H, Abrams P. Is the bladder a reliable witness for predicting detrusor overactivity? J Urol. 2006;175(1):191– 194.
11. Roehrborn CG. Definition of at- risk patients: baseline variables. BJU Int. 2006;97(Suppl 2):7– 11.
220 Challenging Concepts in Urological Surgery
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12. Lewis AL, Young GJ, Selman LE, et al. Urodynamics tests for the diagnosis and manage­ment of bladder outlet obstruction in men: the UPSTREAM non- inferiority RCT. Health Technol Assess. 2020;24(42):1– 122.
13. Gormley EA, Griffiths DJ, McCracken PN, Harrison GM, McPhee MS. Effect of transurethral resection of the prostate on detrusor instability and urge incontinence in elderly males. Neurourol Urodyn. 1993;12(5):445– 453.
14. Sønksen J, Barber NJ, Speakman MJ, et al. Prospective, randomized, multinational study of prostatic urethral lift versus transurethral resection of the prostate: 12- month results from the BPH6 study. Eur Urol. 2015;68(4):643– 652.
15. Roehrborn CG, Barkin J, Gange SN, et al. Five year results of the prospective randomized controlled prostatic urethral L.I.F.T. study. Can J Urol. 2017;24(3):8802– 8813.
16. Ray AF, Powell J, Speakman MJ, et al. Efficacy and safety of prostate artery emboliza­tion for benign prostatic hyperplasia: an observational study and propensity- matched comparison with transurethral resection of the prostate (the UK- ROPE study). BJU Int. 2018;122(2):270– 282.
17. HTA 19/ 39 Commissioning Brief— Minimally invasive operative interventions for bladder outlet obstruction due to benign prostatic hyperplasia. May 2019.
18. National Institute for Health and Care Excellence. Lower urinary tract symptoms in men: management. Clinical guideline [CG97]. May 2010, updated June 2015. National Institute for Health and Care Excellence. https:// www.nice.org.uk/ guidance/ cg97
19. National Institute for Health and Care Excellence. GreenLight XPS for treating benign pros­tatic hyperplasia. Medical technologies guidance (MTG29). June 2016. National Institute for Health and Care Excellence. https:// www.nice.org.uk/ guidance/ mtg29
22
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CASE
Chronic retention, renal failure, and diuresis
Cherrie Ho and James Jenkins
Expert commentary Marcus Drake
Case history
A 74- year- old gentleman was referred to the urology department by his general practi­tioner with impaired renal function, discovered as part of an annual check- up. At the point of referral, an abdominal ultrasound had been arranged which demonstrated bilateral hydroureter, moderate to gross hydronephrosis (Figure 22.1), and a post­micturition volume of 2640 mL.
Learning point Definitions of urinary retention
Definitions of retention have been set out by the International Continence Society in the recent standardization for male lower urinary tract symptoms (LUTS).1 This states that urinary retention is the complaint of the inability to empty the bladder completely. The two main types of retention are as follows:
Acute urinary retention (AUR) is the complaint of a rapid onset, usually painful suprapubic sensation (from a full bladder) due to inability to void (non- episodic), despite persistent intensive effort.
Chronic urinary retention (CUR) is the chronic or repeated inability to empty the bladder, despite the ability to pass some urine. This may result in the frequent passage of small amounts of urine or urinary incontinence and a distended bladder.
Figure 22.1 Ultrasound scan illustrating hydronephrotic kidney, with slight loss of parenchyma.
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Expert comment Post- void residual and hydronephrosis
There is no consensus as to a volume threshold to define urinary retention,2 but a post- void residual (PVR) of >300 mL is often used as evidence of CUR.3 This may be an innocuous incidental observation for some people. However, if it is associated with hydronephrosis, the implications for renal function are concerning. Accordingly, CUR can be subdivided into high- pressure chronic retention (HPCR) or low- pressure chronic retention (LPCR), referring to the detrusor pressure at the end of voiding, that is, the lowest pressure in the bladder at any time in the micturition cycle. Patients with LPCR have a poorly contractile bladder and do not typically develop hydronephrosis. HPCR usually occurs in association with bladder outlet obstruction (BOO), so it is associated with poor urinary flow rates despite the high pressure. The constantly raised bladder pressure impairs ureteric emptying, with consequent bilateral hydronephrosis, and potential for renal impairment. Formally these definitions are based on urodynamic findings; however, new- onset enuresis (bed- wetting), a palpable bladder, and radiologically demonstrated dilatation of the upper tract strongly indicates HPCR.
On questioning, the patient described a sense of incomplete bladder emptying for several years and occasional nocturnal enuresis, but reported a reasonable urinary flow rate. His medical history was that of hypertension and a previous left hip replace­ment only, and he was otherwise fit and active. His medications were mirabegron, sil­denafil, atorvastatin, and amlodipine. He was a retired truck driver and an ex- smoker.
Expert comment Overactive bladder drugs and urinary retention
Antimuscarinics are the first- line drug treatment for symptoms of overactive bladder syndrome (OAB). They inhibit muscarinic receptors, and work by blocking the effect of the low- level acetylcholine release during the storage phase of the micturition cycle. In theory, they can block neuromuscular transmission in many autonomic organs. In the bladder, this could mean inhibiting the nerve signals driving the bladder contraction for voiding. However, at the very low doses used clinically in OAB they have minimal effect on voiding for normal people. In people with a high PVR, they may be best avoided in case of unwanted additional suppression of detrusor muscle voiding function, and hence further impaired bladder emptying. The European Association of Urologists recommends avoiding the use of antimuscarinics in men with PVR >150 mL. Abrams and colleagues demonstrated a modest increase in PVR, but no effect on AUR in men with mild to moderate BOO treated with an antimuscarinic.6 Similarly, the NEPTUNE study demonstrated low rates of AUR when combining antimuscarinics with alpha- 1 adrenergic blockers (tamsulosin) in men with mixed storage and voiding symptoms.7 Beta- 3 agonists (such as mirabegron) are another medication used in OAB. The mechanism is different from antimuscarinics, as they work by eliciting detrusor muscle relaxation directly. In theory, they may introduce the same risk of increasing PVR in men with already impaired voiding. However, they apparently have limited impact on PVR in observational evaluation.8 In the current case, there is a reasonable chance that mirabegron had originally been started due to increased urinary frequency on the assumption that OAB was the cause, whereas the reality may have been that CUR was already present and causing frequent small voids. Accordingly, mirabegron was discontinued.
4,5
Clinical tip Initial investigations for urinary retention
Routine urinalysis: to exclude urinary tract infection.
Routine blood tests: to establish baseline and risk factors, notably renal function and full blood count.
Renal ultrasound: indicated in patients with abnormal renal function and those with high- volume retention.
Abdominal imaging: if diagnosis is uncertain. Intra- abdominal pathology (e.g. perforated bowel, abdominal aortic aneurysm) and ascites can mistakenly be referred into hospital as urinary
retention. Patients should be re- examined soon after catheterization to confirm resolution of
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symptoms and to exclude any serious underlying causes.
Prostate- specific antigen: not routinely recommended during the acute episode, due to difficulty interpreting an elevated value.
Clinical examination revealed a distended bladder, which was palpable to the level
of the umbilicus. Digital rectal examination revealed normal anal tone and an enlarged but benign- feeling prostate.
The patient was admitted to the urology ward following insertion of a Ch14 Foley
urethral catheter in the emergency urology clinic. An initial 3500 mL of straw- coloured urine was drained in the first 2 hours. Hourly urine output monitoring was under­taken, showing a diuresis with an average urine output of 500 mL per hour and he required supplementary intravenous fluids. He received 3 L of Hartmann’s solution over 15 hours with careful fluid input and output monitoring.
Expert comment Potential neurological factors
A rare potential cause of CUR is neurological lower urinary tract dysfunction. In an emergency setting, spinal cord compression can present with non- painful urinary retention, due to impaired motor and sensory function. Two crucial potential causes are central prolapsed intervertebral disc and bony metastases (of which advanced prostate cancer is a notable cause9). A history of back pain, and physical examination identifying saddle anaesthesia (reduced perianal, perineal, and genital skin sensation) and decreased anal sphincter tone on digital rectal examination are crucial. If spinal cord or cauda equina compression is suspected, immediate magnetic resonance imaging must be undertaken for further assessment in the emergency context. This is to identify if cord compression is present, and identify the cause. If identified, same- day treatment (disc prolapse surgery or radiotherapy to a metastasis) is needed in order to minimize progression of the neurological problem, including the potential development of paraplegia.
223Case 22 Chronic retention, renal failure, and diuresis
Clinical tip Initial treatment of urinary retention
AUR: urgent catheterization of the bladder should be carried out by a competent clinical practitioner. Urine volume drained in the first 15 minutes must be accurately recorded to enable distinction between acute and acute- on- chronic retention (i.e. a person with preceding CUR who becomes unable to void at all, leading to emergency presentation).
CUR: early catheterization is indicated principally if there is renal dysfunction and/ or hydronephrosis. If there is no renal dysfunction, catheterization can be avoided, but early listing for definitive treatment should be planned.
Expert comment Haematuria after catheterization
Haematuria is a well- recognized complication following catheterization for CUR. This is caused by the decompression of a urinary tract that has undergone structural changes including bladder hypertrophy leading to weakening of surface capillaries. Decompression haematuria usually settles within 48– 72 hours, but it can be severe, sometimes requiring bladder washouts via the catheter. Historically, gradual decompression (or intermittent clamping of the catheter) had been the practice in many urological units in attempt to reduce the incidence of bleeding. In fact, it has since been demonstrated that attempts to reduce the speed of bladder decompression make minimal difference to the chance of bleeding. In one randomized trial, haematuria occurred in 11% of people undergoing gradual decompression and the same with rapid decompression; six patients in the former group and four in the latter required further treatment.10 Accordingly, the policy currently is to catheterize on unimpeded free drainage, but maintain observation to identify any problems arising early.