The most common cause of AUR is benign prostatic hyperplasia, which is considered a medical emergency. The incidence of AUR is highest in men in their 60s to 80s. Research shows that 10% of men >70 and about 30% in their 80s will develop AUR.1

Until evidence can confidently demonstrate that multiple-use is as safe as single-use of catheters, healthcare providers should advocate a single use of catheters in individuals with spinal cord injury

In women, common causes of AUR and CUR include for example some medications, nerve injury during surgery, cystotomy during operation, or obstruction (vaginal haematoma, vaginal packing, sling, urethral foreign body, pelvic organ prolapse, urethral injury, constipation, failure of pelvic floor relaxation).3

Non-neurogenic causes of CUR include for example an underactive bladder or chronic outlet obstruction. CUR can lead to hydronephrosis, renal failure, and chronic urinary tract infections (UTIs).5

The majority of CUR cases are caused by chronic neurogenic disorders and will therefore be the focus of this article. Neurogenic lower urinary tract dysfunction (NLUTD) – previously referred to as the neurogenic bladder – refers to the abnormal functioning of either the bladder, bladder neck, and/or  sphincters. Causes include neurological disorders such as spinal cord injury (SCI), spina bifida (SB), or multiple sclerosis (MS).1,2,5,6

About 90% of patients with SCI, 95% of those with SB and between 50%-80% of patients with MS develop CUR. CUR can also be caused by detrusor dysfunction, causing the bladder muscle to weaken as a result of chronic overdistention.4

According to the 2021 American Association of Urology (AAU)/Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction (SUFU) guideline on Adult Neurogenic LUTD, NLUTD has a significant impact on patients’ quality of life (QoL). For example, Lo et al showed that given the choice, SCI patients did not have a preference when asked to choose between improvement in bladder/bowel function versus the ability to walk.6,7

Evaluation and diagnoses

Stoffel et al propose that non-neurogenic CUR should be suspected in patients with an elevated post-void residual (PVR) of >300ml that has persisted for at least six months and is documented on two or more separate occasions.5

According to the AAU/SUFU guideline, there is no definite upper limit of bladder volume below, which constitutes a normal PVR, nor is there a lower limit of volume above, which defines an abnormal or elevated PVR in patients with NLUDT. However, the National Institute for Health and Clinical Excellence guidelines define CUR in men as a PVR of >1000ml.6,8

The AAU/SUFU guideline does recommend that an elevated PVR, is generally considered abnormal and should prompt further evaluation using multichannel urodynamic studies (UDS), the gold standard to assess LUTS, as well as the initiation of treatment.6

The AAU/SUFU guideline furthermore recommends that NLUTD patients should be stratified as either low-, moderate-, high-, or unknown-risk (see Table 1).6

Table 1: Risk stratification of patients with NLUTD

Stratification                Signs/symptoms             Recommendations
Low risk Patient presents with suprapontine lesions (eg Parkinson’s disease, brain tumour, cerebral palsy), or lesions distal to the spinal cord (eg disk disease, pelvic surgery, diabetes) but without NLUTD-related complications. These patients can void spontaneously and have a low PVR, their renal function is normal/stable and they have no complications such as bladder stones, elevated PVR or recurrent UTIs Surveillance is not indicated. Re-evaluate and repeat risk stratification if patient presents with new complications (eg UTIs, renal function deterioration) or if symptoms change
Moderate risk UDS demonstrate urinary retention, bladder outlet obstruction, or DO with incomplete emptying. PVR is elevated, however, upper urinary tract (UUT) imaging and renal function is normal/stable History, examination,  symptom assessment and renal function assessment should be repeated annually and renal imaging every one to two years. UDS should be repeated if there are signs and symptoms, new complications or UUT or renal function deterioration
High risk UDS demonstrate poor bladder compliance, elevated detrusor storage pressures with DO, DESD, vesicoureteral reflux (if done with fluoroscopy). UUT imaging indicates hydronephrosis, new renal scarring, parenchyma loss, staghorn and a large or increased stone burden. Renal function tests results are unnormal/unstable History, examination,  symptoms and renal function assessment should be repeated annually. UUT imaging should also be repeated annually and UDS should be repeated when clinically indicated or if there is a change in signs and symptoms or new complications and/or UUT or renal function deteriorate
Unknown risk Patient present with suprasacral spinal cord lesions (eg SCI, MS, transverse myelitis, spinal dysraphism) or other neurological lesions with identified GU complications potentially related to NLUTDs and changes in LUTS Recommendations are similar to all the of the above risk groups

Potentially life-threatening complications in patients with NLUTD

Patients with SCI and MS are at great risk of detrusor overactivity (DO), characterised by involuntary contractions of the smooth muscle fibres found in the wall of the bladder during the filling phase, and detrusor-external sphincter dyssynergia (DESD). DESD is characterised by involuntary contractions of the external urethral sphincter during an involuntary detrusor contraction and is caused by neurological lesions between the brainstem (pontine micturition centre) and the sacral spinal cord. DO and DESD are associated with sequelae such as recurrent UTIs and renal impairment, increasing patients’ risk of mortality and morbidity. 6,9,10,11

Patients with SCI are also at increased risk of autonomic dysreflexia (AD), another potentially life-threatening condition. AD refers to an abnormal, overreaction of the involuntary (autonomic) nervous system to stimulation.6

How is NTLUD managed?

Management includes non-surgical and surgical interventions. Priorities in the management NLUTD include:6,12-17

  1. Preservation of renal function
  2. Freedom from UTIs
  3. Efficient bladder emptying
  4. Freedom from indwelling catheters
  5. Patient agreement with the management modality
  6. Avoidance of medication after proper management.

Non-surgical interventions

Clean intermittent, single-use, sterile catheterisation (CIC) is the gold standard for the management of patients with NLUDT. According to Newman et al, CIC is widely available, is minimally invasive, and perceived as an easy and painless procedure. Another benefit is that it has a limited impact on the patient’s daily activities, thus improving QoL.6,18,19

The authors of the best practice recommendations for bladder management in spinal cord-afflicted (SCA) patients in South Africa, emphasis that CIC is the gold standard for all three phases in the management of these patients. The three phases are:18

Phase 1: Early/acute management

Phase 2: Rehabilitation (preferably in a specialised centre)

Phase 3: Post discharge/rehabilitation.

Saadat et al explain that there are two main options for those electing for CIC – either the traditional reuse of catheters with a form of cleaning between uses, or single-use catheterisation. Furthermore, catheters are available with hydrophilic or polyvinyl chloride (standard) coatings.2

Newman et al demonstrated that the reuse of catheters may pose a potential safety concern due to colonisation by microorganisms. In addition, they showed that single-use catheters were the first choice among patients opting for CIC.19

This was a prospective, multi-centre, clinical trial studied involving patients (n=39) who opted for reusable catheters but agreed to prospectively evaluate single-use hydrophilic-coated (HC) catheters for four  weeks. At the time of the study, these patients had been using reusable catheters for a mean of 10 years, six times a day. Catheters were used for a mean of 21 days.19

The primary outcome was the impact of reusable versus single-use catheters on health-related QoL (HRQoL). A validated Intermittent Self-Catheterization Questionnaire (ISC-Q) was used to obtain HRQoL. Reused catheters were collected and studied with regard to microbial and debris contamination.19

A total of 36 patients completed the prospective test period and the mean ISC-Q score increased from 58 to 67.2 when patients switched to the single-use HC catheters. At the end of the study, 83% preferred to continue using single-use HC catheters. All collected reused catheters (100%) were contaminated by debris and 74% were contaminated by microorganisms, some with biofilm.19

Numerous other studies have shown that a longer duration of catheter reuse resulted in an increased prevalence in the presence of bacteria in the urine culture without any urinary tract symptoms (asymptomatic bacteriuria), and an increase in the incidence of UTIs in patients who reused catheters compared to single-users.2

A 2014 review showed that single-use hydrophilic catheters can reduce the risk of UTI by about 20%–30%, while the estimated risk of UTI in those who reuse catheters was about 70%–80%.2

In another study, Rognoni and Tarricone showed that the frequency of UTI was lower in patients who use hydrophilic catheters and the estimated risk reduction was found to be 16%.20

According to Defoor et al, hydrophilic catheters have lower friction than uncoated catheters resulting in less damage to the urethra. They compared the incidence of UTIs in paediatric patients using hydrophilic versus uncoated catheters and which one was preferred by patients.21

Two UTIs were reported in patients in the hydrophilic group compared to 17 in the uncoated catheter group. Patients with UTIs in the hydrophilic group went from 16% in the previous year to 5% during the study. The patients that completed the study with hydrophilic coated catheters were overall satisfied and many requested to continue using this catheter.21

Saadat et al point out that if reusable urinary catheters are to be used for CIC, sanitation becomes particularly important. Several methods have been proposed including: cleaning with antibacterial soap and water, alcohol sterilization, using aseptic solutions, such as chlorhexidine 1.5% and cetrimide 15%, microwave sterilisation or simply rinsing with water and combinations of these methods.2

Chan et al investigated several sanitation methods. They found that antibacterial wash alone failed to sanitize 67% of catheters on day one, 22% on day three and 44% on day seven. For combined antibacterial wash and microwave heating the positive rate was 0% on day one, 22% on day three and 56% on day seven. Overall 44% of catheters washed with antibacterial soap yielded E. coli vs 26% with combined antibacterial soap-microwave treatment. The latter is a more effective but not an absolute way to sanitise catheters for intermittent use. Longer storage time increased the risk of E. coli growth on the catheters.24

Christison et al conducted a comprehensive review of single- versus multiple-use catheters and concluded that ‘until evidence can confidently demonstrate that multiple-use is as safe as single-use of catheters, healthcare providers should advocate a single use of catheters in individuals with SCI, especially considering that catheter cleaning is a major issue because there is no standardised and universally accepted cleaning method that would be the prerequisite for multiple-use of catheters’.25

Benefits of hydrophilic-coated catheters for CIC

Cardenas et al showed that the use of a hydrophilic coated catheter for CIC is associated with a delay in the onset of the first antibiotic-treated symptomatic UTI, and a 21% reduction in the incidence of symptomatic UTI in patients with acute SCI during acute inpatient rehabilitation. Using a hydrophilic-coated catheter minimises UTI-related complications, treatment costs and rehabilitation delays, and reduces the emergence of antibiotic-resistant organisms.22

A meta-analysis regarding intermittent catheter usage by Li et al reviewed five randomised controlled trials involving 462 patients with SCI or SCA. They found a significantly lower incidence of reported UTIs in the hydrophilic-treated  single-use group when compared with the non-hydrophilic-treated (uncoated disposable and multiple use) group.23

Haematuria was also significantly less common in the hydrophilic catheter group than in the non-hydrophilic catheter group. Their meta-analysis found that UTIs and haematuria are less frequently associated with the use of hydrophilic-coated catheters for CIC in patients with SCI.23

One of the main drawbacks of single-use catheters is cost. The costs associated with complications caused by reusable catheters should be taken into consideration when have to choose between these two options, state Saadat et al. Furthermore, numerous studies have shown the positive impact of single-use catheters on patients’ QoL.2

Other non-surgical therapies include for example pelvic floor muscle training for appropriately selected patients with NLUTD, antimuscarinics or beta-3 adrenergic receptor agonists or a combination of both to improve bladder storage parameters,  alpha-blockers to improve voiding parameters in NLUTD patients who spontaneously void and onabotulinumtoxinA for patients who are refractory to oral medications to improve bladder storage parameters, decrease episodes of incontinence, and improve QoL measures.6

Surgical interventions

Surgical interventions include:6

  • Sphincterotomy to facilitate emptying in appropriately selected male patients
  • Urethral bulking agents for patients with stress urinary incontinence
  • Slings for selected patients
  • Artificial urinary sphincter for patients with stress urinary incontinence and acceptable bladder storage parameters
  • Bladder neck closure and concomitant bladder drainage methods to select patients with NLUTD and refractory stress urinary incontinence
  • Posterior tibial nerve stimulation to select spontaneous voiding NLUTD patients with urgency, frequency, and/or urgency incontinence, sacral neuromodulation to select NLUTD patients with urgency, frequency, and/or urgency incontinence. The latter should not be offered to patients with SCI or SB
  • Augmentation cystoplasty to select NLUTD patients who are refractory to, or intolerant of, less invasive therapies for DO and/or poor bladder compliance or continent cathererisable channels, with or without augmentation to facilitate catheterisation
  • Ileovesicostomy for selected patients
  • Urinary diversion for patients in whom other options have failed, or are inappropriate, to improve long-term QoL.

Conclusion

According to Saadat et al, the main arguments in choosing between single- and multiple-use catheters are risk of UTIs, uncertain cleaning methods, social issues, and finally the cost and QoL.2 Theron et al, concur, stating that consideration of the patient’s QoL and needs, their therapeutic goals and economic status must become the measure of care.18

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